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View Full Version : Year long discussion of "Another nosegear failure" -09/19/2010


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TS Flightlines
03-06-2011, 09:18 AM
But what is the tube diameter of the nose gear?
Tom

Jim Wright
03-06-2011, 07:20 PM
Maybe this is the answer



http://www.youtube.com/watch?v=wWbEmOqrb4A

Jim Wright
03-07-2011, 11:25 AM
I was wondering how my nose gear pant got those scratches, now I know.
Perhaps Vans could resolve this nose gear problem with something like this:

Copy Paste

http://www.youtube.com/watch?v=wWbEmOqrb4A

Looks like it needs a shimmy dampner

RobinHou
03-07-2011, 04:12 PM
This nose gear in the YouTube video look much stronger than the Vans gear without fore aft movement. Does any one know who they are?

tracker
03-07-2011, 05:11 PM
http://www.vansairforce.com/community/showthread.php?t=64850

tracker
03-07-2011, 05:14 PM
http://www.vansairforce.com/community/showthread.php?t=68751

I am following, and hoping a better solution is engineered and tested by the time I will be at this stage in the build.

bignose
03-29-2011, 02:25 PM
Here is the way everyone should land an A to stay out of trouble...

http://www.airliners.net/photo/Tipsy-T-66-Nipper/1882796/ :D

LifeofReiley
03-29-2011, 02:46 PM
Here is the way everyone should land an A to stay out of trouble...

http://www.airliners.net/photo/Tipsy-T-66-Nipper/1882796/ :D

Yepper... That is the way it's done. :)

daveball
09-10-2012, 02:23 PM
l just installed two mods from this company. This mod is supposed to keep the gear leg from folding under the aircraft. l couldn't get it on my 9 fast enough,although it only takes a couple of hours.Just check out Al's video at Antisplat.com. and see what you think. The second mod is the LIP-Skid,and this gives more surface area should the fork tube contact the ground. The are a great company,to work with. l initially got the wrong lip skid, and Al sent the right one no-charge. l have been flying out of a grass strip,since 2005,with the original fork set-up.

ianxbrown
09-19-2012, 08:22 AM
This does appear to be a serious problem, and not clearly always pilot error, but I'm prepared to admit that, if anything, my speed was a bit high, and maybe I didn't hold far enough back on the stick AFTER landing. I flipped over destroying everything except the wings and the instrument panel. I'll rebuild but with a better nosegear. I like what I've seen of the AntiSplat solutions, especially the new bearing. I had noticed that the conical bearings were very difficult to get freely turning and at the same time just the right tightness.

panhandler1956
09-19-2012, 08:26 AM
This does appear to be a serious problem, and not clearly always pilot error, but I'm prepared to admit that, if anything, my speed was a bit high, and maybe I didn't hold far enough back on the stick AFTER landing. I flipped over destroying everything except the wings and the instrument panel. I'll rebuild but with a better nosegear. I like what I've seen of the AntiSplat solutions, especially the new bearing. I had noticed that the conical bearings were very difficult to get freely turning and at the same time just the right tightness.

Sorry to hear that! I can't image how tramatic that would be. Glad everyone was ok.

flyboy1963
09-19-2012, 09:12 AM
Ian, not sure if you'll see this....but when you feel like talking about it, can you elaborate on what happened? Just for the eductional component of course. I am nervous fast taxi-ing across asphalt seams, but it would be good to know that an actual flip requires 40 knots and a big gopher hole or whatever.
If it truly takes only 5 knots and a banana peel, then I am inclined to ground my bird until I have all the mods installed!

Vlad
09-19-2012, 09:44 AM
Ian you have the courage to post it man. Appreciate it. I am with Perry please share more if you can. Sometimes I land on very aggressive surfaces it's never too late to learn.

Rupester
09-19-2012, 10:56 AM
My first flight was Sunday and the nose gear "issue" is my biggest fear. I too would like to understand the conditions at the time of your incident, but only when you're ready to talk about it. Again, so very very sorry ....

Ron Lee
09-19-2012, 12:58 PM
Just saying that you flipped without details...especially the surface...is not helpful.

I avoid grass...period. I have taken steps to minimize the chance of this happening and with about 1600 hours in a 6A, I cannot agree that this is a "but for the grace of God" situation.

gasman
09-19-2012, 02:52 PM
Just saying that you flipped without details...especially the surface...is not helpful.

He did say he was going a bit too fast, and not holding full aft stick.

Ron Lee
09-19-2012, 03:16 PM
He did say he was going a bit too fast, and not holding full aft stick.

Maybe a factor, but I doubt it was the root cause. The surface is the most likely causal factor in my opinion.

RetiredRacer
09-19-2012, 05:49 PM
Maybe a factor, but I doubt it was the root cause. The surface is the most likely causal factor in my opinion.

Sure surface can be a contributing factor but I believe it is only one of the many factors that can cause the collapse of the front nose gear. I will say this, I believe "AntiSplat" is onto it. Their gear leg device helps to make the front leg more robust and will help it withstand the abuse it can receive (except perhaps from Gopher holes and anything else that will allow the fork nut to dig in but their skid plate may help here). As long as the front wheel is spinning I believe the surface can be as rough as it likes, as long as that nut does not dig in. And the key word here is "Spinning". If the wheel is spinning when it touches down it will deflect that front leg less as it "spins up" to aircraft speed. Holding the front wheel off as long as possible will allow more chance of the wheel doing about the same speed as the aircraft when it touches down. A wheel pant fitted and a free spinning front wheel axle assembly will have the front wheel spinning when it touches down. If the front wheel drops into rough surface rut on touch down or on roll out, as long as it is spinning it will pull itself out of that rut.

Here is a post from another thread where I was asked my opinion of the AntiSplat leg device.

[I fitted the "antisplat" recently before the wife started training in our 9a. I know some people do not believe in the product but my wife in her training has given the front a real workout with a couple of wheel barrow jobs .

And I had to do an off field maneuver once to dodge some "Roo's" that were hiding in the late afternoon shadows. It was late roll-out when I saw them and I went through some big bumps in avoiding the Roo's. I hit my head on the canopy and was expecting the front leg to go "splat". But the device did it's job and you can see where it has been working on the powder coating.

For nothing else, it was worth the cost just for some piece of mind coming into land at some unfamiliar bush strip. For me, it allows me to concentrate on the landing at hand, instead of trying to see what the condition of the surface is.]

Most of my flying is into bush strips as that is where I believe most of the fun is.

Bob Dennis
RV9a
Australia

PerfTech
09-19-2012, 05:59 PM
...I had the pleasure of talking to Ian at length about this terrible mishap and it looks like the textbook gear rolling up like a snail, nose pitching down to the ground with the pitching momentum carrying the aircraft onto it's back. The field wasn't that rough and he saw no gopher hole or large depression that started the chain of events, only the typical trench 40 or 50' long where the gear leg after bending skidded along. The actual flip over usually occurs as the speed is coming down from rubbing on the ground. If you have the standard Vans front wheel bearings and outside spacers then you are on the ragged edge any time you encounter an irregular landing surface. The more irregular or bumpy the surface, the higher the potential for disaster. When this original bearing set up tries to roll over a bump or out of a depression with any foreword speed the bearings try to lock-up, and do so. This is exactly the same as landing with a front wheel brake fully applied. The rolling action is transferred into the gear leg from the locked wheel.This rolls the gear leg around the tire, setting into motion the failure event. Once it starts it gets bigger and bigger until the gear leg fails. This can actually occur on a paved surface if it is allowed to progress unchecked. See this video; https://vimeo.com/46060731 . This phenomenon is solely attributable to the standard bearings and is impossible to create after the bearing and spacer modification is performed. With the "Lip Skid" "Nose Job" and "Ball Bearing Upgrade" This type of accidents can virtually be eliminated. It is possible to bend the gear of course by hitting a curb or a giant hole but the entire face of the accident will be changed due to the position where the bending takes place. Most likely preventing the flip over. Thanks all, Allan...:eek::eek::eek::eek:

PCHunt
09-20-2012, 01:06 AM
The link took me to a sign-in page for Vimeo, but no video.

ctbecker
09-20-2012, 09:35 AM
Allan, is the Ball Bearing mod mentioned above and the 'nose wheel bearing mod' on your web site the same?

PerfTech
09-20-2012, 09:48 AM
Allan, is the Ball Bearing mod mentioned above and the 'nose wheel bearing mod' on your web site the same?

...Yes that is the one. Thanks, Allan...:D

PerfTech
09-20-2012, 09:58 AM
The link took me to a sign-in page for Vimeo, but no video.

..Try this; https://vimeo.com/46060731 I also fixed the link in the original post! Thanks, Allan....:D

diamond
09-20-2012, 10:44 AM
Just saying that you flipped without details...especially the surface...is not helpful.

wow .

ianxbrown
09-20-2012, 04:30 PM
So here is some more info on this landing. I'll do the best I can to be honest with myself.
This was a grass strip almost 3,000 in length. There was a modest 7kt crosswind. I'd say it felt fairly windless as we crawled out of the inverted aircraft. There were no serious bumps to be seen but I'd have to report there was a lot of bouncing along the runway on landing. If I look at possible sources of pilot error I'd have to say I don't remember holding hard back on the stick after landing, but I normally to do that. I had the right approach speed (60-65 kts is my usual approach). In the last few moments before landing I was watching the trees either side of me and making sure I stayed straight so I didn't see my speed on touchdown. On the runout we seemed to cover a lot of ground so one possibility is that I dropped the nose to make the runway, and picked up some speed but I don't conciously recall doing that at all. It felt very normal as we touched down, with no particular concerns when the wheels made contact, neither in landing distance or attitude.

In the last three seconds I was concerned that we would run out of runway. I had never landed here before, and the end seemed awfully close compared to my home airport which is 5,000' of tarmac. I began to apply brakes which is when the trouble started. The aircraft started bouncing at the nose, and then lurched up (as though we'd hit a non-existent bump). As it came down the nosewheel seemed to bury in. Very quickly after that the propeller made contact with the ground which flipped us over.

The nose gear fairing had come off at the start of a groove about 40yds long. The other end of that groove was where we flipped. The lower part of the nose gear was wrapped around the wheel. The upper part was bent but seemed to have fared better than the engine mount which has one tube bent and a fracture across the top centre section.

The wings were OK. I'm buying an already built empennage. The propeller is in good enough shape that it's in for repair. I'm in the process of removing the engine to have it torn down and inspected. The fuselage has some small distortion at the firewall and a kink at the baggage compartment bulkead. It looks like the safest would be a rebuild of the fuselage.

The canopy is toast but the roll bar survived intact. One last thought. Those discussions about something to break the canopy open miss the point. When you flip over the canopy breaks open so what you really need is not something to break it open but something that will break off the sharp broken pieces. When you're upside down everything is a little harder to find too! Snug five point seatbelts really work. Really tight is better than somewhat tight.

gasman
09-20-2012, 05:02 PM
All good information........ Thank You!

jongurley
09-20-2012, 05:23 PM
Thanks for the info Ian, , one question for the population, has a RV'A model with the antisplat nosejob flipped over yet, that anyone knows of????

AlexPeterson
09-20-2012, 05:41 PM
Thanks for the info Ian, , one question for the population, has a RV'A model with the antisplat nosejob flipped over yet, that anyone knows of????

Ian, glad you are physically ok, so sorry to hear about the plane.

Regarding the question above, it is probably confounding data - most, if not all, with the anti splat feature probably have decent wheel bearings as well. I've written ad nauseum on the wheel bearing problem...

My question for about 4 or 5 years has been "have any flipped with a rigid type of axle/bearing setup?". Extremely hard to get this information.

I will note that the number of incidents has dropped sharply since the discussion about wheel bearing/axle design. Hopefully, the anti-splat will be icing on that cake!

Great comment about the canopy breakers. Maybe some sort of handle with a slot in it for busting loose remaining plexi? Something vaguely like a crescent wrench set at about a quarter inch.

rustyscrew
09-21-2012, 07:14 AM
I did the same as you describe with my nose gear and new fork. Also I added a oak cove moulding on the aft side of the strut secured with duct tape which will be replaced w/glass
now that it's a proven fix. Landed and taxied on several grass strips and parking areas with no problem. Walt RV-6A

Ron Lee
09-21-2012, 07:34 AM
I will note that the number of incidents has dropped sharply since the discussion about wheel bearing/axle design. Hopefully, the anti-splat will be icing on that cake!

Do you have factual statistics showing this? How does "discussion" result in a drop in flipovers?

Either people avoid the primary causal surface (non-paved in my OPINION) or they make a physical change that reduces the chance of this happening.

That would also require that a huge percentage of people make the changes (physical and/or operational).

I did change to the new fork, added a carbon fiber skid plate to the nose wheel pant but more importantly..I avoid non-paved surfaces.

Ironflight
09-21-2012, 08:12 AM
I also know of several flip-overs in the past year that haven't been reported here (I have seen them on the FAA daily reports, and sometimes from direct accounts from witnesses of incidents that were quickly wheeled into hangars and not reported).... so the forums are simply not a reliable data source for anything but anecdotal discussions.

diamond
09-21-2012, 08:24 AM
I'm curious how many RV-10 flip-overs do we know of ?

prkaye
09-21-2012, 08:46 AM
I installed an upgraded matco axle to my nosegear a while back. The new axle goes right through the wheel and replaces those mushroom thingies. Is the aerosplat bearing upgrade equivalent to this or does it go farther?

PerfTech
09-21-2012, 09:20 AM
I installed an upgraded matco axle to my nosegear a while back. The new axle goes right through the wheel and replaces those mushroom thingies. Is the aerosplat bearing upgrade equivalent to this or does it go farther?

....The Anti-Splat-Aero ball bearing upgrade uses three spacers that serve as stack-up parts, allowing you to tighten the axle up completely. There is no need to worry about preload on the bearings and they are double sealed, never needing service or maintenance of any kind. When we perform this modification, we precision balance the wheel separately. We then mount, true (if necessary) and balance the tire as most are off a considerable amount. These sealed bearings are permanently installed in the wheel and don't fall out on the ground when removing or changing the tire....Thanks, Allan:D

rocketbob
09-21-2012, 09:26 AM
I also know of several flip-overs in the past year that haven't been reported here (I have seen them on the FAA daily reports, and sometimes from direct accounts from witnesses of incidents that were quickly wheeled into hangars and not reported).... so the forums are simply not a reliable data source for anything but anecdotal discussions.

Since I started this thread two years ago there have been two more flip-over accidents within 20 miles from my home airport. One of them was a first x/c after the builder spent 15+ years building the airplane. Both on grass.

Folks thats seven flip over accidents I know of personally. Absolutely absurd that this has not been addressed by Van's. Fortunately the anti-splat mod does the trick.

If you don't have the anti-splat mod, you're crazy!!

pierre smith
09-21-2012, 09:30 AM
I'm curious how many RV-10 flip-overs do we know of ?

Mark, the -10's nosegear is hinged at the motor mount and in the past, has simply folded UP, in the one forced landing that happened after a fire broke out. There are several rubber doughnuts that provide the spring.

Best,

apkp777
09-21-2012, 09:44 AM
F.W.I.W. - I know of one RV-7A, that had the nose wheel fold under (did not flip) on a paved runway. He was an adamant "technique, technique, technique" guys. Now he's installed the anti-splat...Seems he has changed his tune. By the way, he had lot's of RV time and a skilled pilot.

Anyone who thinks this is not a design flaw is foolish. (IMO)

Pmerems
09-21-2012, 09:50 AM
"Fortunately the anti-splat mod does the trick. If you don't have the anti-splat mod, you're crazy!!"

I must be crazy or I missed something? Where is the proof? Real world testing? Statistics? Show me the proof and I'm in. Allan has a very nice video on his site, but that isn't the proof it will prevent this from happening.

I transitioned trained with Mike Seager up in Oregon on a grass strip. Average condition for a grass strip. "A" models fly out of there all the time. No "A" model flip overs to my knowledge on this grass strip.

Every morning I look at the latest NTSB accident reports. What I find interesting is that a good percentage of accidents are nose gear collapses on many GA airplanes. An interesting statistic. Is it poor flying skills? Bad hardware? I don't know but maybe there is something in these statistics that is telling us something.

I agree with Allan that with the existing nose wheel bearing/fork design you can pinch the bearing and cause additional drag on the wheel. However a simple machined spacer inserted between the two factory spacers solves that problem.

868RM
09-21-2012, 11:20 AM
About 3 yrs. ago I purchased a rv 8a kit in progress only to learn later about the "problem". I researched the options at that time & there was no anti splat. We then did a very complete analysis of strength of std. gear leg. Not much room for error & I make errors! I also fly 99.9% off grass fields. We then designed a stronger gear leg (about 30% stronger),modified the rv 10 fork to fit on new leg,put larger tires on mains and nose (used grove wheels & duel piston brakes),fitted grove nose wheel with ball brg.'s & spacer between brg.'s & added a fiberglass damper to back of the leg. The new leg is designed for the longer rv 10 fork & about 2 1/2 in. shorter to compensate for tire dia. This total change adds about 4 lbs. I have 150 plus grass landings with some not so pretty. Anyone that does not think there are any issues and does not do the brg. update and antisplat has NOT done any design calculations.Yes the stock is OK , but you are a much better pilot than me and have your front axle bolt at some perfect torque. Thanks Ron I always wear a helmet when I ride my motorbikes too.

N427EF
09-21-2012, 11:43 AM
I am confused, this is not unusual but 868RM,
what are you talking about?
An RV8A or an RV10 or what?

N941WR
09-21-2012, 11:55 AM
F.W.I.W. - I know of one RV-7A, that had the nose wheel fold under (did not flip) on a paved runway. He was an adamant "technique, technique, technique" guys. Now he's installed the anti-splat...Seems he has changed his tune. By the way, he had lot's of RV time and a skilled pilot.

Anyone who thinks this is not a design flaw is foolish. (IMO)

Like Tony, I know of a local -6A and a -9A that were both damaged (bent nose gear, prop strike, etc.) but did not go over. Those two will never show up on the stat's.

Does the Nose Job work? I don't know but if I had an "A", I would replace the front axle with the Matco unit and then think about the Nose Job.

diamond
09-21-2012, 12:01 PM
Don't want to open a big can o worms, but with the advent of the new 14 model with 10-like nosegear, I wonder if there will now be any reasonable way to incorporate this nosegear style into the build of a 7, 9, or other?

jclark
09-21-2012, 12:31 PM
"Fortunately the anti-splat mod does the trick. If you don't have the anti-splat mod, you're crazy!!"

I must be crazy or I missed something? Where is the proof? Real world testing? Statistics? Show me the proof and I'm in. Allan has a very nice video on his site, but that isn't the proof it will prevent this from happening.

I transitioned trained with Mike Seager up in Oregon on a grass strip. Average condition for a grass strip. "A" models fly out of there all the time. No "A" model flip overs to my knowledge on this grass strip.

Every morning I look at the latest NTSB accident reports. What I find interesting is that a good percentage of accidents are nose gear collapses on many GA airplanes. An interesting statistic. Is it poor flying skills? Bad hardware? I don't know but maybe there is something in these statistics that is telling us something.

I agree with Allan that with the existing nose wheel bearing/fork design you can pinch the bearing and cause additional drag on the wheel. However a simple machined spacer inserted between the two factory spacers solves that problem.

The Anti-Splat seems to be a great add-on for the "A" models.
AS well as the other add-ons they provide. Great to see innovation!!

I fly a 6 and I am perpetually building a 6A. Have flown a lot of "A" models.

The Anti-Splat does not though, defy laws of physics.
(And I would bet that its designer would tell you the same. :-) )

It is possible to flip your 6/7/9 A with one if the conditions are correct even though you may be an "ACE pilot".

So, get all the extra safety margin you need or feel the desire for but please do not let you guard down because it has been installed. I have friends (plural) who did and ended up bending stuff. Away from the fervor of a forum, they, like some here have, admitted to things they could have done otherwise.

And **ALL** are FANTASTIC pilots.

More later ....

James

868RM
09-21-2012, 01:16 PM
Ernst, Line one rv 8a . James , I agree the anti-splat provides support mostly in one axis. This nose wheel thing is more like motorcycle high speed wobble than grocery cart shimmy. Ron

Finley Atherton
09-21-2012, 04:50 PM
So here is some more info on this landing. I'll do the best I can to be honest with myself.
This was a grass strip almost 3,000 in length. There was a modest 7kt crosswind. I'd say it felt fairly windless as we crawled out of the inverted aircraft. There were no serious bumps to be seen but I'd have to report there was a lot of bouncing along the runway on landing. If I look at possible sources of pilot error I'd have to say I don't remember holding hard back on the stick after landing, but I normally to do that. I had the right approach speed (60-65 kts is my usual approach). In the last few moments before landing I was watching the trees either side of me and making sure I stayed straight so I didn't see my speed on touchdown. On the runout we seemed to cover a lot of ground so one possibility is that I dropped the nose to make the runway, and picked up some speed but I don't conciously recall doing that at all. It felt very normal as we touched down, with no particular concerns when the wheels made contact, neither in landing distance or attitude.

In the last three seconds I was concerned that we would run out of runway. I had never landed here before, and the end seemed awfully close compared to my home airport which is 5,000' of tarmac. I began to apply brakes which is when the trouble started. The aircraft started bouncing at the nose, and then lurched up (as though we'd hit a non-existent bump). As it came down the nosewheel seemed to bury in. Very quickly after that the propeller made contact with the ground which flipped us over.

From his description I don't think the pilot did much that was wrong in this latest example. Maybe a bit fast on touchdown but the incident happened near the end of the landing roll when presumably the elevator had insufficient power to keep the nose off the ground anyway. Also I suspect the pilot had considerable back stick and this contributed to the nose lurching up. This has happened to me a few times - nearing the end of the landing, full back stick, hit the "right" bump and the nose rapidly and unexpectedly jumps up. The natural reaction is to ease the stick forward which can exacerbate the situation by making the nose come down harder. IMHO about the only thing you can do in this situation is to come off the brakes and continue to hold back stick.

I am approaching 500 hrs on my 9A with most of my landings on short grass strips. Some of these strips have been very rough and undulating. I have the antisplat brace installed. I believe that the strut mostly flexes fwd. and up over bumps and this increases the distance between the ground and the wheel pant/nut/bottom of the fork, so what might have happened in this latest example?

In the antisplat video Allan shows that a significant bump moves the drag vector fwd, this combined with tight wheel bearings (speculation) could have started the wheel tuck under. Hopefully the brace would help prevent this type of situation developing further.

I think it is more likely that the nose cone fairing contacted the ground when the nose came down heavily. Any contact with the fairing would instantly increase the drag forces further compounding the situation.
In my opinion if it gets to the point where the bottom of the fork/nut is digging in then the drag forces would be so great that even the antisplat brace may not save the day.

Most people consider that it is critical that the bottom of the strut/big nut never be allowed to touch the ground and that a skid plate be installed in case this happens. To me it is critical that not even the bottom of the nose cone fairing be allowed to touch the ground as the drag produced is the start of the flip over sequence. IMHO if the bottom of the nose cone fairing never touches the ground then there is very little chance of a flip over.

Tyre pressure should be kept high to prevent the tyre compressing and reducing the ground clearance. I use 35 to 40 psi - makes for a more unpleasant "jiggly" ride on the nose but I think it is safer.

The newer style nose fork and shorter strut gave 1" extra ground clearance but I think this is pretty much wasted from a safety point of view unless the bottom of the nose cone fairing is reshaped to move it higher. I did this (http://www.vansairforce.com/community/showthread.php?t=20219) about 5 years ago and there is no evidence that the nose cone fairing has ever contacted the ground even on some very rough strips.

Maybe Antisplat Aero could produce a reshaped nose cone with more clearance???

Fin
9A

Ron Lee
09-21-2012, 05:10 PM
Pending making any mods that may help, you may reduce your chance of this happening to near zero by staying on paved surfaces.

STAY OFF OF GRASS/DIRT SURFACES!

This is being decried as a design flaw yet is easily handled with operational restrictions.

I saw the aftermath of one 6A flipover. It reportedly started by wheelbarrowing badly or some such nose first landing.

By the marks on the asphalt, you could see most of the developing issues. The plane did not flip until it went off the paved surface onto dirt/grass. My opinion is that it likely would not have flipped if it had stayed on pavement another ten - twenty yards.

gasman
09-21-2012, 05:23 PM
With the strut in front of the fork and ahead of the axle, when weight is applied to an excess, the faring tucks under.... and if it contacts the tire, it stops it from spinning causing the tire to trip on the faring (nose cone) and trying to pull it under. Kind of like a lady tripping (stepping) on a long dress.

The bearing / axle situation can cause enough drag that the nose cone hits the ground and drags on the tire enough to have the nut dig in and then over you go.

Allow extra clearance between the cone and the tire. And then make a brace in the cone to the front of the fork so it can't be forced back and hit the tire. Maybe make the bottom of the cone very thin so it will fail first and not trap the tire.

tkatc
09-21-2012, 05:50 PM
In the absence of a bullet-proof solution, the anti-splat solutions seem like our best bet. It has been in service for awhile now.... Any reports of tip overs/fold unders while using this product?

I have not seen nor heard details of failures of the anti-splat but I did hear mumblings of such an incident. I don't want to spread rumors but if we have useful data it should be presented here.

Like I said, I think anti-splat is our best solution to date but if there has been failures I would like to be an informed consumer.

Insight?

L.Adamson
09-21-2012, 06:09 PM
Pending making any mods that may help, you may reduce your chance of this happening to near zero by staying on paved surfaces.

STAY OFF OF GRASS/DIRT SURFACES!



Yep----------because my surface was paved..........I didn't flip. Just curled the nose gear under, and destroyed my Hartzell constant speed prop. In fact, the bounce that got it, was slow motion with no momentum.

I too, may have landed a bit fast, and didn't flare properly. This event followed my best landing ever. I had started using full flaps more often, as most previous landings were done with half flaps. I also added a bit of power to smooth out the descent, since my wife was on board. Much of the time, I'd do the steep power off approach, with a flare at the exact moment before airspeed & plane falls through the floor. An RV6(A) with a Hartzell drops like a rock.

As I touched the runway, I bounced about two feet high. My wife and I remarked that this wasn't the best landing, since the one before was so smooth. I didn't think a lot about it, let alone power up. This went into a second bounce, a bit higher than the first. I thought it would just stop at the point. I wasn't thinking PIO until after. At this point, the tail seemed to rise at a very low airspeed, with the nose pointing down. Now......I was certain that applying power would end with a cartwheel off the runway.

At no time, was my wife or I, distressed of the situation. The bounces just seemed too small to be of consequence. When we again hit, nose down, the airplane just stopped with no forward momentum. The engine was still idling, but with the tail up, I knew what the prop would look like. I had installed a wood shimmy damper on the nose gear, about three weeks before. It was found broken, on the runway, at one of the bounce locations.

I'm certain that the anti-splat bar would have saved my prop & required engine tear-down. It became available shortly after my adventure. If I was to do it all over again, I'd certainly have added power at the first bounce. It just seemed so benign.

L.Adamson

rvbuilder2002
09-21-2012, 06:37 PM
From his description I don't think the pilot did much that was wrong in this latest example. Maybe a bit fast on touchdown but the incident happened near the end of the landing roll when presumably the elevator had insufficient power to keep the nose off the ground anyway. Also I suspect the pilot had considerable back stick and this contributed to the nose lurching up. This has happened to me a few times - nearing the end of the landing, full back stick, hit the "right" bump and the nose rapidly and unexpectedly jumps up. The natural reaction is to ease the stick forward which can exacerbate the situation by making the nose come down harder. IMHO about the only thing you can do in this situation is to come off the brakes and continue to hold back stick.



Actually, in the statement made by the pilot he suggests that he may not have had the stick full back during the landing roll out, and he mentioned that the runway was nearly 3000 ft long.

I will likely ruffle some feathers (whats new), but may I suggest couple of things.

First - Does everyone remember being trained in soft field landings when they learned to fly? It has been a long time since I took my primary training, but the main points I remember are Make the softest touch down possible, at the slowest speed possible, and hold the nose gear off as long as possible
It seems as though pilots now adays have gotten the idea that soft field means a plowed field behind a farmers barn, so they ignore all they were originally taught. A soft field is actually any non paved surface. Yes, sometimes a grass runway is softer than other times, but my point is... any time you line up short final on a non paved runway, you should be thinking soft field... soft field.... soft field...

Second - 3000 ft is a long runway for an RV-9(A). Any pilot with the level of proficiency that any of us should have if we have any business flying one should be able to easily get down and stopped in 1000-1200 ft (tall trees on approach end would add a few 100 to this). The pilot said he became worried about the end of the runway coming up and began braking a bit harder. That means that in this landing situation, the rollout went nearly double what it should have had too. my guess (that is all any of us do right?) is that it was far from a totally normal landing. To me that means that what happened during the final portions of the landing roll out is anyone's guess.

I say this to by no means cause more pain than this latest accident already has, because I feel very bad for the pilot/owner (BTW, I have already done this type of repair to a fuselage, I recommend you repair it vs replace it...PM me if you would like some advice).

Going a bit off topic now...

I readily admit that the nose gear on RV's is not the stoutest ever put on an airplane. Considering how many factory built (for heavy duty abuse) airplanes get the nose gear ripped out of them (and often times flipped also), it really shouldn't surprise anyone that RV's (with a lighter duty nose gear) have their share also (the same pilots that fly factory built airplanes are the same pilots that fly RV's).
It is unfortunate that the nose gear design that was chosen, by design, is capable of storing energy which can make a flip over more possible.
Everything is a trade off. Designing for minimal weight is one of the primary factors that make an RV's performance so desirable by all of us. If RV's were designed for all levels of abuse, like factory built airplanes are, they would likely fly like the factory airplanes and no one would care about them.
Case in point... the RV-14 was designed a bit more on the heavy duty side, and many have praised the new landing gear design. Those same people have complained about the poor speed performance and heavy weight compared to an RV-7... You get my point????

In closing.... I own an RV-6A (which was flipped by its previous owner - accident report HERE (http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20050615X00776&key=1)) and at my home airport I make all takeoffs from a paved runway and all landings on a grass runway (unless it is soggy from rain). The airplane has an all original nose gear (no mods). I am meticulous about maintaining proper tire pressures.
When I turn final I think to my self soft field.... soft field.... soft field....

The reason I included the link to the accident report is to show that a lot of the flip accidents are clearly the fault of the pilot and it may well have happened regardless of what they were flying. In this instance, I know of details that the pilot admitted to me, but not the accident investigator. I have a feeling, that because of the circumstances (we all have some level of pride), that this occurs a lot.
My main reason for making this comment is in the hope that people will have an open mind and read between the lines a bit before they pin the blame of every flip over accident on the nose gear.

I believe this is far from reality, and I will keep flying my dangerous, unmodified airplane using the proper care, in the way I was originally trained to do, with no fear.

This thread has never been short of questions people would like answers too... One I have always wondered.... is if a poll has ever been done, or if anyone knows of any data, of how many of the pilots involved in tri gear RV landing accidents received training from one of the transition training instructors? I wonder if Mike Seager has any idea?

Ron Lee
09-21-2012, 07:04 PM
RVbuilder, clearly there are RV pilots who operate safely out of non-paved surfaces. The question then is what is different between those who do operate with no problems and those who flip?

You may have diagnosed this incident perfectly. You may have hit upon a generic problem reference soft field technique.

Does Mike Seager operate an A model extensively out of a grass strip? If so, what is different between his situation and those who flip on grass/dirt?

N941WR
09-21-2012, 07:33 PM
...STAY OFF OF GRASS/DIRT SURFACES!...
Ummm, the the two A's I mentioned earlier were both on pavement. I'm not sure this is the answer.

...I too, may have landed a bit fast, and didn't flare properly...

Interesting point Larry. I wonder if the accident sequence starts with "fast" approaches.

Today I was helping a friend who is transitioning to his recently purchased -9A. The prior RV pilot he flew with was telling him to approach at 80 MPH / 70 Kts rather than the 70 MPH / 60 KTS dual or 65 MPH / 55 KTS Solo that I found works very well in the 9?s.

rvbuilder2002
09-21-2012, 07:47 PM
Does Mike Seager operate an A model extensively out of a grass strip? If so, what is different between his situation and those who flip on grass/dirt?

Mike's base of operations is K05S (Vernonia Oregon). It is a grass runway. I believe he does most training operations from other airports and then when the students skills have been polished to the point Mike desires, they do landings at Vernonia.

I don't know the answer to the second question. Mike hangs out here on VAF some, maybe he is willing to comment.


I am thinking I didn't make my intended point very clear in my long post. The main point I wanted to make is that the situation has evolved to the point where if this type of accident happens, people seem to automatically assume it is totally the airplanes fault. My opinion is that a large % of the accidents were caused by mistakes that would have damaged most any airplane.

L.Adamson
09-21-2012, 08:46 PM
Interesting point Larry. I wonder if the accident sequence starts with "fast" approaches.

Today I was helping a friend who is transitioning to his recently purchased -9A. The prior RV pilot he flew with was telling him to approach at 80 MPH / 70 Kts rather than the 70 MPH / 60 KTS dual or 65 MPH / 55 KTS Solo that I found works very well in the 9?s.

At least it was a "skip" bounce, and not a "plop" bounce, as in a stall. If I knew exactly what I did, then there wouldn't have been a problem, I suppose. There just must have been a moment of less attention. Because of full flaps, the nose may have also been pitched more downward.

My 6A speeds were the same as a Piper Archer. 90/80/70 knts. A friend fly's his 9A the same, except in mph, which is about 10 mph slower. I'd usually round out, looking to be close to the runway at 65 knts. From there, the speed diminishes very quickly, if power is at idle.

L.Adamson

N941WR
09-21-2012, 08:50 PM
... A friend fly's his 9A the same, except in mph, which is about 10 mph slower. I'd usually round out, looking to be close to the runway at 65 knts. From there, the speed diminishes very quickly, if power is at idle.

L.Adamson
Still way too fast in a -9(A). Seriously, I do all my approaches with power off and 60 Kts with two up or 55 Kts solo and never drop it on. In fact, I can and do roll it on and used those same speeds with my friend's -9A. He was stunned at how smooth we were landing. BTW, both of those RV's have FP props. A CS prop might act differently due to the breaking effect and weight on the nose.

But this is a discussion for a different thread. maybe one we can hound each other about CS vs. FP props or ...

L.Adamson
09-21-2012, 09:00 PM
Still way too fast in a -9(A). Seriously, I do all my approaches with power off and 60 Kts with two up or 55 Kts solo and never drop it on. In fact, I can and do roll it on and used those same speeds with my friend's -9A. He was stunned at how smooth we were landing. BTW, both of those RV's have FP props. A CS prop might act differently due to the breaking effect and weight on the nose.

But this is a discussion for a different thread. maybe one we can hound each other about CS vs. FP props or ...

His is also a Hartzell C/S. And just like my 6A, it doesn't "float" either. His 9A's speed also diminishes very quickly. We've both "plopped" it in, when experimenting.

edit: and as I remember, his 9A is at least 75-100 lbs. lighter.

Ron Lee
09-21-2012, 09:05 PM
Like Tony, I know of a local -6A and a -9A that were both damaged (bent nose gear, prop strike, etc.) but did not go over. Those two will never show up on the stat's.

Ummm, the the two A's I mentioned earlier were both on pavement. I'm not sure this is the answer.

Yes and the one incident that I saw (after the fact) was due to pilot error landing on the nose gear. How about the two cases you mentioned?

A faster approach speed is NOT the issue in and of itself.

L.Adamson
09-21-2012, 09:13 PM
But this is a discussion for a different thread. maybe one we can hound each other about CS vs. FP props or ...

Should my plane ever be rebuilt............we can argue as to whether I can land it, as a "6" or not. Or will I just groundloop it? :D

Finley Atherton
09-21-2012, 10:20 PM
Still way too fast in a -9(A). Seriously, I do all my approaches with power off and 60 Kts with two up or 55 Kts solo and never drop it on. In fact, I can and do roll it on and used those same speeds with my friend's -9A. He was stunned at how smooth we were landing. BTW, both of those RV's have FP props. A CS prop might act differently due to the breaking effect and weight on the nose.

I use the exact same speeds with a CS prop. Any faster and my 9A can float excessively.

I agree with RVbuilder about landing technique (Post #302) but my understanding is that many of these incidents occur at slower speeds nearer the end of the landing when the nose wheel has dropped to the ground even with full back stick held. At this point it does not matter how good the earlier approach and touchdown was as the only option left is full back stick. In this phase of the landing all you can do is hold back stick and trust that you do not hit a bump big enough to contact the lower nose cone/bottom of the fork/big nut.

To take an extreme example it is even possible to have the strut fold back while parking (http://www.vansairforce.com/community/showthread.php?p=21677#post21677) if the lower nose cone fairing contacts the ground (note that this happened some time ago and with the older style fork/strut which had 1" less ground clearance that the current version).

This is why it is my strong belief that you must do everything possible to avoid nose cone contact including higher tyre pressure and maximising ground clearance under the lower nose cone fairing.

Fin
9A

jjconstant
09-21-2012, 10:56 PM
I feel compelled to point out that there is actually a rather surprising variation in IAS from plane to plane, depending on airspeed calibration, or lack thereof. Maybe those people giving airspeeds that they use for approaches could include the IAS of their stalls so that someone with an indicated airspeed that reads faster than actual doesn't come in with too little energy. I think typical approach speed is 1.3Vso FOR YOUR airplane's indicated stall speed. I also think the mention of differences between CS and fixed was a helpful reminder as well as the differences between airframes (9 vs 6,7,8).

I fly a 7A, WW (light) CS prop. I can't remember my static weight on the nose wheel at gross off hand but it would probably be helpful to be included in these discussions too. In my airspeed calibration the gross weight stall occurrs at 57kts indicated. I use 1.3Vso=75kts on approach (actually should be 74 but I'm not that good yet). I'll keep it there until I need to round out. I also have AOA and 75kts lights up the first amber LED at a normal glide slope with a bit of power. This feels rock steady. If I come in any slower things can easily get very wobbly and I instinctively add power. I just don't like it when my RV starts wallowing like the Cessna 150 I trained in:rolleyes: Yeah, I could probably come in a hair slower, but why? I still can easily make the first turnoff at 1500ft when I want, but I am perfectly comfortable not using the brakes at all and letting it roll to the next one at 2000ft. There's another 3000 to play with. I have 210hrs and I'm still on the set of brakes and tires that came with the kit. I am always quick to add power in the flare if there's even a sniff of anything not right. The amount of power added is directly proportional to the size of the question mark hovering over my head during flare:D

Just blindly using someone else's numbers could be very painful. Especially if it's a different model or the same one with very different equipment, calibrations and W&B.

rocketbob
09-22-2012, 06:24 AM
"Fortunately the anti-splat mod does the trick. If you don't have the anti-splat mod, you're crazy!!"

I must be crazy or I missed something? Where is the proof? Real world testing? Statistics? Show me the proof and I'm in. Allan has a very nice video on his site, but that isn't the proof it will prevent this from happening.

I transitioned trained with Mike Seager up in Oregon on a grass strip. Average condition for a grass strip. "A" models fly out of there all the time. No "A" model flip overs to my knowledge on this grass strip.

Every morning I look at the latest NTSB accident reports. What I find interesting is that a good percentage of accidents are nose gear collapses on many GA airplanes. An interesting statistic. Is it poor flying skills? Bad hardware? I don't know but maybe there is something in these statistics that is telling us something.

I agree with Allan that with the existing nose wheel bearing/fork design you can pinch the bearing and cause additional drag on the wheel. However a simple machined spacer inserted between the two factory spacers solves that problem.

So no reports of flip-overs with Allan's mods isn't good enough for you? I suggest if the practicality of his simple and inexpensive mods doesn't work for you, take your chances.

Like I said I know of SEVEN, repeat SEVEN RV nose gear failures near me and if RV's were somehow comparatively within the fleet percentages of nosegear failures of other airplanes then there would be piles of wrecked C150's 172's, Cherokees, etc around here.

Ron Lee
09-22-2012, 07:16 AM
Like I said I know of SEVEN, repeat SEVEN RV nose gear failures near me....

Bob, that is interesting yet of no value in objectively looking at this issue WITHOUT facts surrounding each event.

I know of one event and it was clearly pilot error based upon the eyewitness reports.

My suggestion remains: Stay off of grass/dirt runways and we can add to that "Do not land on the nosegear."

I also know of one RV-6A landing on a paved runway where the nose wheel fairing was torn off. Factors: The runway had large cracks in it. They landed with a non-trivial tailwind. So paved runways in poor condition should also be avoided.

Oh my...Three operational restrictions that should make this a non-issue. I can live with those.

Ironflight
09-22-2012, 08:41 AM
Like I said I know of SEVEN, repeat SEVEN RV nose gear failures near me and if RV's were somehow comparatively within the fleet percentages of nosegear failures of other airplanes then there would be piles of wrecked C150's 172's, Cherokees, etc around here.

Actually Bob, if you read the daily FAA accident reports, you'd find that there are WAY more reports of wrecked landing gear on Cessnas, Pipers, etc in a month than RV's. Of coure, the Certified fleet is larger, and the only accidents listed are those that are reported - many aren't.

Ron Lee
09-22-2012, 09:01 AM
There is useful info on at least one of the SEVEN flips that Bob knows about locally. From Post #11:

He used to keep his airplane in my hangar but was concerned about the nosegear not being up to the rough spots in the runway, so he moved it to a nearby airport. Yesterday he elected to not give rides to friends until the wind shifted in favor for 18 which is smoother. This was his third landing of the day here.

Had the nosewheel fork mod according to Van's service bulletin.

Landed and rolled out over a spot on the runway with a bit of a hump. Following the hump is a low spot where grass does not grow well. The airplane took a bounce over the hump and the nosewheel came down in the bare spot. It was clear to see where the front wheelpant broke and the nut started digging in.......

So the runway had conditions that are not suitable for an A model. The pilot knew about it but made multiple landings/take-offs anyway.

Then Bob knows of a pilot who has flipped TWICE. Come on folks. You want to use that as justification that the nose gear is a horrible design that is just waiting to nail you?

Judgment folks....judgment.

Stay off of poor paved runways and unimproved runways.

There is a grass strip west of here that a Cub pilot with tundra tires claims is like a putting green. It sounds like a nice area but without firsthand knowledge of the conditions, I will not land there. I probably would not even if I knew that it were perfect.

I am looking at the wheel bearing mod. Maybe I will do it...maybe not.

Av8torTom
09-22-2012, 09:41 AM
I'm in the nose job modification can't hurt camp. I am not convinced either way about its effectiveness, but I am convinced that it won't hurt anything either.

For those of you who are waiting for poof of it's effectiveness, forget it - you're going to wait a LONG time because you're trying to prove a negative. Not impossible, but you'll need a ton of data points.

We may be able to prove it DOESN'T work if we look at the data 10 years from now and can show there is no difference in the number of flip over events between those A models with and those without the modification. Again though, a lot of data will be needed.

So unless someone can convince me that there's an inherent risk to doing the modification, I plan on putting one on my 9A along with the wheel bearing change.

868RM
09-22-2012, 09:49 AM
Ron, I could not accept 2 of your 3 operating restrictions. We cannot make new nose gear parts to fix all pilot errors. However that is what I love about experimental aircraft , we can cover the minor ones. In my case Ron's restrictions are just unacceptable so I made the changes I felt were needed to still be safe on grass with a nose wheel. I feel the brg. spacer with std. wheel is must on any surface. The spacer "stiffens" the fork to keep the bearings from skewing and binding. Next it is much more difficult to skew and bind a ball bearing, hence brg. change. The anti-splat strut is such a simple add on I don't understand the reluctance to put one on. If lots of grass strips is your normal (I fit in this group) the 5.00x5 nose wheel and g380-150-5 main tires roll over bumps with a lot less effort. The nose gear is more likely to flex up instead of back.This requires a new fork. A complete new nose gear can be made too. They are not that expensive and are made by the same shop that made the nose leg that you have now. None of these options are very difficult and WILL help prevent flip overs. Physics works with or without statistics. Ron

Ron Lee
09-22-2012, 10:10 AM
Ron, you need not heed my operational restrictions. You have made the mods that you feel are needed. There are folks who successfully operate out of unimproved strips.

But my view...without hard data...is that the majority of the flips are on unimproved surfaces. It may also be by pilots with limited experience on those surfaces.

So the OBVIOUS solution is stay off of unimproved surfaces if you are not 100% certain that you can successfully use it. The initial post was because a pilot who had left an airport with an unimproved strip made multiple landings/take-offs. Until the flip occurred. It should never have happened.

My flying is not substantially impacted by avoiding unimproved surfaces.

Make the mods or not. But these incidents can be reduced to near zero (opinion) if RV-xA pilots stay off of unimproved surfaces (qualified folks exempted).

868RM
09-22-2012, 10:52 AM
Ron, Very well stated. I hope that "A" pilots do their own research and determine that there are a few simple things that will help. Ron

rvbuilder2002
09-22-2012, 11:17 AM
I agree with RVbuilder about landing technique (Post #302) but my understanding is that many of these incidents occur at slower speeds nearer the end of the landing when the nose wheel has dropped to the ground even with full back stick held.

I don't pretend to know all the answers, but I can imagine a possible cause for this....

A large # of the flip-over accidents that I have first hand info. about were situations were the pilot was getting short on runway remaining. Some of these were situations where the pilot was still in the air and forced the airplane on the ground (pretty much guaranteed to ruin your day). Many of the others were good landings (they resisted forcing the airplane on the ground and waited to touch down in a full nose up flair), but because of extra speed and/or miss judgment of a proper touch down point they ended up rolling a bit long on the runway and the flip happened near the end of the roll-out.
Think for a minute about the dynamics of this situation...
Airplane is still rolling moderately fast so the pilot is braking hard. Because of the vertical position of the C.G. relative to the main and nose wheels, this automatically shifts more weight than normal, onto the nose gear. If the pilot is holding full back stick (as he should be), this will help counter the pitching moment produced by the de-acceleration. But what if the situation is getting a bit tight and the pilot keeps the hard braking going right until the end. So there is a strong pitching moment throughout the entire roll-out, but as the speed is decreasing, the elevator authority is decreasing. This means that the weight load on the nose gear may be increasing during the entire roll-out.
An example of this we have all experienced is an emergency stop in a car. The front end dives towards the ground and we are pushed fwd against the belts. If it is a true panic stop in a vehicle with ABS, we will stay tight against the belts until the instant that the vehicle actually stops.
The exact same thing happens in the airplane. The pitching may actually be worse because of how tall the airplane sits up on the gear.
We have something the car doesn't have.... pitch control. This helps reduce the pitching moment... until its effectiveness is reduced because of low airspeed. Add into the situation a bad pump just before the airplane is about to stop (now very low elevator effectiveness, but highest amount of weight on the nose gear), which pitches the nose up and it slams back down with the original increased load caused by the hard stop + the acceleration added from the nose dropping, and we have a bad situation.
So you might say that not all of the accidents happen near the end of a runway. I agree.
What if, because it is a shorter grass runway (a lot of them are) a pilot decides to practice his short field landing skills (or maybe a bunch of his buddy's are watching) so he brakes hard even though he didn't really need to. (Refer to explanation above of what can happen if you brake hard to a complete stop). He is actually trying to see how short he can land (or impress his buddys), so he is going to brake hard to a full stop right? He is not going to think, there, I got it slowed down to 30 kts pretty quick, and then stop braking.
Now he may have done everything right (right on the proper airspeed, and touched down at the very beginning of the runway), so that he will be stopped at about the mid point of a 2000 ft runway (actually pretty good performance for someone that doesn't do it all the time), but he didn't need too, and he may pay a hard price for it.

I can imagine scenarios (but still guesses, just like everyone else) that could explain many of the flip-over accidents. The explanation above I believe covers a lot of them, particularly if you also add in improper maint. (low nose tire pressure), excessive weight on nose gear, etc., to the mix. One thing I am sure of... we don't always hear all of the pertinent details of these accidents. I don't mean to imply that it is always intentional (though I think it sometimes is), but if we did know all the facts, I think most of us would have a very different opinion about what caused the accident.

tjo
09-22-2012, 12:32 PM
Keep in mind that I am not an RV pilot yet. I am building a 9 and I am in the process of convincing my wife that this is the right choice over a 9A. I started in a Cub, she didn't.

That said, I have seen quite a few RV's land and have been surprised at how many A models I have seen touch down on the nose gear at almost the same time as the mains. I am assuming that the pilots are thinking that they are high on the mains, but they aren't. Incidentally I have seen the same behavior with certified airplanes as well.

I have also found it interesting that I did my primary training on airstrips that were mostly 3,000 feet or less, and a good third of my landings were on short grass strips. I can tell you that people who "grew up" on 5,000 foot paved strips will think they are runnng out of runway, when in reality there is lots of room left. I can also tell you that landing on 1,000 feet of grass with even just tall grass at the end looks awfully short and intimidating and could cause someone to unnecessarily use the brakes, but if done properly, you stop well short of the end of he runway, at least in a Cub.

I have no idea if this is a cause, but it may be a contributor. I am not a high time pilot, but I try to be as observant as possible and I try to push myself to continually learn.

Tim

Ron Lee
09-22-2012, 01:52 PM
Tim, I have recently seen USAFA pilots wheelbarrow/porpoise in expensive Cirrus aircraft at my airport. I do not know if students were at the controls or rated pilots, still, poor technique.

Finley Atherton
09-22-2012, 05:06 PM
I agree with rvbuilder's analysis of how heavy braking towards the end of the landing roll puts a greater load on the nose wheel.
Most of my landings are on my short grass strip and I try to brake heavily as soon as the mains are on the ground with increasing back stick to hold the nose up and then easing off the brakes as the nose comes down so hopefully there will be little need for braking towards the end on the landing roll.

However there has been many occasions where I have had to use at least moderate braking after the nose has come down including on some very rough grass strips. I believe that the strut will take a lot of punishment and will naturally want to flex fwd and up out of danger even under heavy braking on a rough surface provided there is no excessive drag that could force the strut to move back and down instead. That excessive drag could be caused by tight or binding bearings or the lower nose cone contacting the ground. Hence my obsession that everything be done to help prevent the nose cone grounding including high tyre pressure and rasing the lower surface of the nose cone fairing to give more clearance.

Greater clearance does allow the nose wheel to hit a higher bump without grounding but the impact point will be more fwd and higher up on the tire as shown in the Antisplat video and maybe this is when the antisplat brace could be a good backup???

Fin
9A

PerfTech
09-22-2012, 08:11 PM
...It seems that most of the discussion on this thread has been hashed over many times here on this forum. I am quite sure most people are aware of the dynamics at work when braking heavily and the need to avoid as many holes and depressions in the ground as possible. The items from ASA offer some added safety when needed and we have demonstrated this in the video and with a multitude of other tests not in our video. Many factors contribute to this issue, poor technique, surface, wheel drag, lack of experience, mechanical failures, a forced landing and many more. The bottom line is the products offer some added safety, and if available at a reasonable price, one should take advantage of the opportunity at hand. To make a statement like its all technique, or I don't make mistakes, so you don't need it is bordering on irresponsible. With that line of reasoning one could suggest removing the roll bar, seat belts and shoulder harnesses. After all, they just add weight and in a perfect world they definitely aren't needed. I have had several off field forced landings in my forty plus years as a pilot and I can say with 100% certainty that when it gets real quiet up front or the smoke is coming out so goes a lot of technique. That is when the if only I Coulda, if only I Woulda, I Shoulda, begins and that is sad. Also it seems possible Vans made a blunder in putting that more expensive, much larger, stronger, more complex and somewhat better designed nose gear on their new RV-14. Why not keep the original design, beefed up if needed? If it wasn't broke, why fix it? My Three Cents, Allan

tjo
09-22-2012, 08:24 PM
Allen, I think you have a good product and I am impressed with the professional development that you have put into it as well as the transparency with which you have provided data. It is to be applauded. If I do build an A, I very likely will put your stuff on it.

That said, the guys at Vans are also very experienced not only as pilots, but with their machines as well, and they choose to fly without them. I don't consider them irresponsible, or I wouldn't be buying stuff from them.

There have been many times during my career that I have dealt with experts with differing opinions. I have also BEEN an expert with a differing opinion. It will happen as long as we can't prove something for sure.

Tim

PerfTech
09-22-2012, 09:19 PM
Allen, I think you have a good product and I am impressed with the professional development that you have put into it as well as the transparency with which you have provided data. It is to be applauded. If I do build an A, I very likely will put your stuff on it.

That said, the guys at Vans are also very experienced not only as pilots, but with their machines as well, and they choose to fly without them. I don't consider them irresponsible, or I wouldn't be buying stuff from them.

There have been many times during my career that I have dealt with experts with differing opinions. I have also BEEN an expert with a differing opinion. It will happen as long as we can't prove something for sure.

Tim

...Thank you for pointing out that I may have worded my previous post in such a way that it's meaning could be misconstrued. I don't consider them irresponsible at all and didn't mean to come across that way. I have the utmost respect for all of them and their company as well. I believe collectively they have done more to further general aviation than anybody. I was simply trying to say many people out there don't posses the skills or have the same experience and this add-on may help save a few of them a lot of grief. I have never flipped an aircraft (knock on grass) in over 14K landings but in looking back, some of those would have definitely bent the nose gear were I in my RV-9A. This being said I was a little nervous about this issue and decided to address it. Over the years many wonderful automobiles have been designed and produced. Then came seat belts and the safety improved. Then all could be bettered with airbags, I look at this the same and hope I don't have occasion to test them. I think they (Vans) have a wonderful product and have tried to address most every issue that came about. I also see they have addressed this issue on the new RV-14A. That doesn't suggest or imply they dropped the ball on the other A models. It just shows they are on top of and improving their products. Again, apologies if I offended anyone as I didn't intend it. Thanks, Allan...:o

rvbuilder2002
09-22-2012, 10:20 PM
...It seems that most of the discussion on this thread has been hashed over many times here on this forum. I am quite sure most people are aware of the dynamics at work when braking heavily and the need to avoid as many holes and depressions in the ground as possible.


...Thank you for pointing out that I may have worded my previous post in such a way that it's meaning could be misconstrued.

I don't think anyone misconstrued your first post... I think it is pretty clear what you meant to say :o

Just to be clear... the post I made explaining my opinion on how a flip over accident could possibly happen at slow speed near the end of a landing roll out was in response to someone asking the question. So it may all seem clear to some people, but obviously not to everyone.

To make a statement like its all technique, or I don't make mistakes, so you don't need it is bordering on irresponsible.
I agree, so I hope this wasn't addressing me, because I never said any of those things.
In the same vein, I think it is irresponsible to imply even the hint that if someone doesn't choose to buy your products, that they are foolish and irresponsible (I am not say you have Allen, but other people surely have).

- - - - - - - - - - - - - - - -

My only motivation for even getting involved in this thread was to get people to look at it with eyes wide open, and maybe consider that many of the accidents are the blame of the pilot and that the outcome may have been exactly the same regardless of what airplane they were flying. If nothing else, I am hopefully encouraging people to do a serious self evaluation of their own personal flying skills. There comes a point when no bolt on fix will save someone from some of the situations people get themselves into. I still firmly believe that is the scenario for a lot of the flip-over accidents.

There is nothing at all wrong with people choosing to add Alan's product to their airplane. My biggest fear though, is that a lot of people are doings so, and now flying with their guard down. They might be thinking that they no longer have to worry, when what they should really be worried about is their less than stellar performance as a pilot. Sorry, I know that can sting a bit, but the best thing we all can do is put our selves in a position were our friends feel empowered to tell us things we need to hear. Even better, is to seek out a good RV pilot and ask them to fly with us ans really critically critique what they see. I know we all do flight reviews every other year, but a lot of those really don't happen in the context that I am describing.
Something good for all of us to consider....

nineninefour
09-22-2012, 10:43 PM
I started my professional life as a safety engineer, doing system safety work on the space shuttle main engine testing program. I am currently a structural engineer (following a masters degrees and some years experience).

In the safety business, our rule was that although we could use human element programs (training, procedures) to prevent mishaps, we were to engineer out things when we could. This issue sounds like one of these. While excellent pilot technique might be a fair control, if we can actually determine the necessary design and construction feature changes, we should strive for those. The other part is that in the event of an unexpectedly rough field, or in an emergency landing situation, we should probably expect the nose gear to remain useable.

The thing that could cause FAA intervention is lack of recognition and responsiveness among amateur builders, when problems are not fixed. We do not want that, so we should not simply blame the pilot and bury our heads in the sand.

ColoRv
09-23-2012, 12:54 AM
...Thank you for pointing out that I may have worded my previous post in such a way that it's meaning could be misconstrued. I don't consider them irresponsible at all and didn't mean to come across that way. I have the utmost respect for all of them and their company as well. I believe collectively they have done more to further general aviation than anybody. I was simply trying to say many people out there don't posses the skills or have the same experience and this add-on may help save a few of them a lot of grief. I have never flipped an aircraft (knock on grass) in over 14K landings but in looking back, some of those would have definitely bent the nose gear were I in my RV-9A. This being said I was a little nervous about this issue and decided to address it. Over the years many wonderful automobiles have been designed and produced. Then came seat belts and the safety improved. Then all could be bettered with airbags, I look at this the same and hope I don't have occasion to test them. I think they (Vans) have a wonderful product and have tried to address most every issue that came about. I also see they have addressed this issue on the new RV-14A. That doesn't suggest or imply they dropped the ball on the other A models. It just shows they are on top of and improving their products. Again, apologies if I offended anyone as I didn't intend it. Thanks, Allan...:o

You say you're not suggesting Van's dropped the ball on the A models, and yet it seems that you suggest exactly that in nearly every post. There appears to be quite a bit of scare tactics in your sales approach and insinuating that anyone who isn't writing you a check is reckless.

The bottom line is the products offer some added safety, and if available at a reasonable price, one should take advantage of the opportunity at hand. To make a statement like its all technique, or I don't make mistakes, so you don't need it is bordering on irresponsible.

It's irresponsible to trust Van's engineering over yours? What are your credentials for saying such a thing? A good product doesn't need these tactics to sell. Van has proven himself and his company many times over.

If you have the standard Vans front wheel bearings and outside spacers then you are on the ragged edge any time you encounter an irregular landing surface.

Snakeoil. Your previous post was misconstrued? Many of your posts seem to say something along these lines. It's a free country and you have the right to slander whomever you please unless they decide to stop you. But slandering Van to make a buck is just a bit off I think. Perhaps your products do add a slight measure of safety, or perhaps they don't....nothing has been proven. It's all stories of unreported blah blah blah and promises of cure all doodads. I've seen my share of accidents, and was jump master in a cessna where the PIC ripped the gear and wings off at the end of the runway...and one thing I'm fairly certain of is the percentage of pilots that admit they porked the pooch after they've clearly and unmistakably done so...is pretty low. Some of the stories of flips are questionable at best, some are quite certainly pilot error that couldn't have been prevented with carrier gear on the front...and maybe some are due to the gear being too weak...for the load the builder/pilot put on them. Bigger engines, constant speed, desire for more baggage capability moving CG further and further forward....I think there is possibly enough blame to go around. I'm very confident of one thing though....if Van thought there was a real issue...he would have said so. Sure, he changed the gear on the bigger, heavier airplanes with six cylinders hanging off the front..and you're trying to turn that into an implied design fault on the smaller, lighter, 4 cylinder planes? Seriously?

Captain Avgas
09-23-2012, 04:48 AM
My only motivation for even getting involved in this thread was to get people to look at it with eyes wide open, and maybe consider that many of the accidents are the blame of the pilot and that the outcome may have been exactly the same regardless of what airplane they were flying. If nothing else, I am hopefully encouraging people to do a serious self evaluation of their own personal flying skills.

Scott, I appreciate your comments, despite the fact that I have been a long term critic of the RV sprung steel nose gear dating back to 2005 when the issue of RV nose failures first began to gain real steam on VansAirforce.

I was taught during my initial training to keep the nosewheel off the ground on landing, and I thought that I did so in a reasonable manner. That was until I did RV transition training with Mike Seager in 2006. Then I promptly understood that my technique was totally insufficient, at least for RVs. He completely changed my perspective...and my technique.

The problem is that most RV pilots graduate from learning to fly on Cessnas and Pipers which obviously have much more forgiving nosegear designs. Typically they bore down the runway at take-off with the nosewheel firmly planted on the ground and pull back on the stick to rotate. On landing they plop the nosewheel down within seconds of the mains touching. You only need to go to any major GA airport to see that this is the norm for most private pilots.

The danger for many RV pilots is that they just don't realise how inadequate their technique really is for RVs. I flew as a passenger with an RV9A pilot recently and I asked him before we left if he made it a practice of keeping the nosewheel off the ground whenever he had elevator authority to do so. He said "yes, always", and then he promptly took-off flat and landed flat. He knew what he was supposed to do in theory....but in practice he just didn't do it.

So my recommendation for any RV pilot who wants to spend some money to improve safety is to start by spending it on some quality transition training with a reputable RV instructor. That could be a very beneficial and illuminating exercise. :)

I still believe that the RV sprung steel nose gear is fragile, but I draw considerable comfort from the fact that Mike Seager, who reportedly has +12,000 flying hours in RVs (most of them instructing low time pilots), doesn't appear to have collapsed an RV nose gear yet. This is despite the fact that he routinely takes students in and out of Vernonia which is a pretty ordinary turf strip surrounded by high trees. I think that probably says volumes about the advantages of good technique.

woodmanrog
09-23-2012, 07:19 AM
I have avoided this forum for a long time but after reading some of these comments, I thought I would enter some of my real world experience. There is always room for improvement on any product be it car, airplane or whatever. That being said: I resisted putting any stiffener on my nosegear airplanes (2 RV6's) because Van's says they are not necessary. I have repeatedly told prospective customers that a nosegear stiffener wasn't necessary to purchase. Well, I have changed my mind. After viewing my friend RV6airplanepilot's videos, I was convinced that I had to at least give it a try and see if there was any difference on my own plane. I installed one of the stiffeners that I personally make, albeit with some minor modifications, and am now convinced that there is really a marked improvement as to vibration and flexation. I am going to purchase the Lipskid device from Allen because it seems to make practical sense and is a relatively inexpensive and simple mod. So my final assessment is that there is improvement in stiffeneing up the standard nosegear no matter which route you want to persue, Perftec or homemade. You will feel a difference, gauranteed.

David-aviator
09-23-2012, 09:18 AM
Well, I have changed my mind. After viewing my friend RV6airplanepilot's videos, I was convinced that I had to at least give it a try and see if there was any difference on my own plane.

No question, your device will stiffen the NG strut. But if that video is the same one I viewed a while back, it is not a totally valid reason to conclude the stiffener is necessary. The video I saw obviously was the result of "holding" the NG on the surface way beyond take off speed. My technique with the 7A was to start the take off roll with some back pressure just like when taxiing and keep the NG unloaded. That technique works both on take off and landing and did so for 5 years of grass ops before we black topped our runway and with a very heavy Subby engine up front.

And this is from a perspective of having experience a flip with that same airplane when the Subby quit one day and the landing was on soft river bottom sand not far from the Missouri River. I do not believe the stiffener would have mattered. The NG bent back when it dug in that was it even aft coming to an almost complete stop.

Keep the weight off the NG as much as possible during take off and landing and barring very bad surface, you will be OK. Also, keep in mind the NG is not designed to be landed on any more than it is on a jet airliner. It is for slow speed and taxi only.

badmrb
09-23-2012, 12:46 PM
If we are still talking about the anti splat brace, its not a stiffner. The point is to not affect the nose gear or its movement under normal conditions. It only comes in contact when the gear is rolling back under because of a severe enough stress to cause gear failure. When it works, things ARE gonna get bent, but higher up at the attach point.

The wheel bearing mod helps stop the situation where the stock bearing is locking/ unlocking and causes the gear to start that forward/back motion.

If we arent talking about the antisplat device then i guess its a whole different discussion of what happens when the nose gear is made rigid and what that does.

L.Adamson
09-23-2012, 01:04 PM
If we are still talking about the anti splat brace, its not a stiffner. The point is to not affect the nose gear or its movement under normal conditions. It only comes in contact when the gear is rolling back under because of a severe enough stress to cause gear failure. When it works, things ARE gonna get bent, but higher up at the attach point.

The wheel bearing mod helps stop the situation where the stock bearing is locking/ unlocking and causes the gear to start that forward/back motion.

If we arent talking about the antisplat device then i guess its a whole different discussion of what happens when the nose gear is made rigid and what that does.

I do believe we're now talking about wooden type stiffeners, as well as the anti-splat. Note: In the old 6A day's, it was common to wrap a wooden stiffener with fiberglass for the nose gear leg. The fiberglass was the actual finished portion of the leg. No pre-made fairings back then.

az_gila
09-23-2012, 01:05 PM
.....

The wheel bearing mod helps stop the situation where the stock bearing is locking/ unlocking and causes the gear to start that forward/back motion.

.....

Interestingly the RVbuilder2002 long response does not mention the front wheel motion.

http://www.vansairforce.com/community/showpost.php?p=701356&postcount=321

It's quite visible to onlookers but not even felt by the pilot. I can't believe that an oscillation like this doesn't have some resonance point....

PerfTech
09-23-2012, 09:22 PM
[QUOTE=
I agree, so I hope this wasn't addressing me, because I never said any of those things.
In the same vein, I think it is irresponsible to imply even the hint that if someone doesn't choose to buy your products, that they are foolish and irresponsible (I am not say you have Allen, but other people surely have).

- - - - - - - - - - - - - - - -

My only motivation for even getting involved in this thread was to get people to look at it with eyes wide open, and maybe consider that many of the accidents are the blame of the pilot and that the outcome may have been exactly the same regardless of what airplane they were flying. If nothing else, I am hopefully encouraging people to do a serious self evaluation of their own personal flying skills. There comes a point when no bolt on fix will save someone from some of the situations people get themselves into. I still firmly believe that is the scenario for a lot of the flip-over accidents.

There is nothing at all wrong with people choosing to add Alan's product to their airplane. My biggest fear though, is that a lot of people are doings so, and now flying with their guard down. They might be thinking that they no longer have to worry, when what they should really be worried about is their less than stellar performance as a pilot. Sorry, I know that can sting a bit, but the best thing we all can do is put our selves in a position were our friends feel empowered to tell us things we need to hear. Even better, is to seek out a good RV pilot and ask them to fly with us ans really critically critique what they see. I know we all do flight reviews every other year, but a lot of those really don't happen in the context that I am describing.
Something good for all of us to consider....[/QUOTE]

...Scott, It seems I owe you an apology and need to clear up a few things. I wasn't addressing you in that post at all, but rather the whole thread as many of these things have been said before. I think your post was great and agree with you on every statement. I have said most all of them myself. I am perhaps a little too passionate about this product and sometimes jump to it's defense to soon becoming frustrated when people don't understand what I was trying to convey. Again I apologize and want you to know this frustration wasn't aimed at you. Thanks, Allan

RetiredRacer
09-23-2012, 10:59 PM
I agree with rvbuilder's analysis of how heavy braking towards the end of the landing roll puts a greater load on the nose wheel.
Most of my landings are on my short grass strip and I try to brake heavily as soon as the mains are on the ground with increasing back stick to hold the nose up and then easing off the brakes as the nose comes down so hopefully there will be little need for braking towards the end on the landing roll.

However there has been many occasions where I have had to use at least moderate braking after the nose has come down including on some very rough grass strips. I believe that the strut will take a lot of punishment and will naturally want to flex fwd and up out of danger even under heavy braking on a rough surface provided there is no excessive drag that could force the strut to move back and down instead. That excessive drag could be caused by tight or binding bearings or the lower nose cone contacting the ground. Hence my obsession that everything be done to help prevent the nose cone grounding including high tyre pressure and rasing the lower surface of the nose cone fairing to give more clearance.

Greater clearance does allow the nose wheel to hit a higher bump without grounding but the impact point will be more fwd and higher up on the tire as shown in the Antisplat video and maybe this is when the antisplat brace could be a good backup???

Fin
9A

....brake while holding the nose up. I thought this would slam the front wheel down. I don't know about yours Fin but with a fair amount of fuel on board and with no passenger or luggage I have trouble holding the front off. But when we are traveling with luggage etc, if we have a distance to travel to clear the runway I'll keep the idle up a little and taxi with the front held up. But if you check the trim tab there is very little difference between loaded and empty.

Finley Atherton
09-24-2012, 02:00 AM
....brake while holding the nose up. I thought this would slam the front wheel down.

Yes, can be done in my 9A at least - don't know about other RV models with smaller elevators and I am just a lowly private pilot and have no special authority/experience to suggest others do the same!

This technique works best for me on a short field landing where there is no extended flare as I want to get on the ground quickly. The extra speed at touch down means there is enough power in the elevator to keep the nose up with brakes applied for a short while. Its a sort of a balancing act between the brakes and increasing back stick. Raising the flaps immediately after touch down can also help keep the nose up slightly longer. Obviously I let the brakes off just before the nose wants to drop to prevent it slamming down hard.

I find the technique does not work as well on a long runway because I think I must automatically extend the flare and the slower touch down speed means the nose wants to drop sooner.

Let me know if you ever plan to fly into Armidale.

Fin
9A

nineninefour
09-24-2012, 01:06 PM
Has anyone here instrumented a nose gear (i.e., strain gauges along the forward and aft gear surfaces) to looking at loading, load rates, deflections, etc.? We could fairly easily do this, accumulate some data, and come to some conclusions about bending forces with various mods and under various operating conditions.
Modeling is good, but I suspect we don't know enough yet about the loads and forces involved at various phases of landing and on various surfaces to construct an accurate model.

RetiredRacer
09-24-2012, 04:45 PM
[Quote] I believe that the strut will take a lot of punishment and will naturally want to flex fwd and up out of danger even under heavy braking on a rough surface provided there is no excessive drag that could force the strut to move back and down instead. That excessive drag could be caused by tight or binding bearings or the lower nose cone contacting the ground. Hence my obsession that everything be done to help prevent the nose cone grounding including high tyre pressure and rasing the lower surface of the nose cone fairing to give more clearance.

Greater clearance does allow the nose wheel to hit a higher bump without grounding but the impact point will be more fwd and higher up on the tire as shown in the Antisplat video and maybe this is when the antisplat brace could be a good backup??? [End Quote]

I agree with your thoughts here Fin but I hadn't thought of the nose cone drag before and as someone else mentioned, that the nose cone could be pushed back into the tyre compounding the issue.

Thanks for the invite, your only a couple of hrs. I'll email you.

PerfTech
09-26-2012, 09:36 AM
[Quote] I believe that the strut will take a lot of punishment and will naturally want to flex fwd and up out of danger even under heavy braking on a rough surface provided there is no excessive drag that could force the strut to move back and down instead. That excessive drag could be caused by tight or binding bearings or the lower nose cone contacting the ground. Hence my obsession that everything be done to help prevent the nose cone grounding including high tyre pressure and rasing the lower surface of the nose cone fairing to give more clearance.

Greater clearance does allow the nose wheel to hit a higher bump without grounding but the impact point will be more fwd and higher up on the tire as shown in the Antisplat video and maybe this is when the antisplat brace could be a good backup??? [End Quote]

I agree with your thoughts here Fin but I hadn't thought of the nose cone drag before and as someone else mentioned, that the nose cone could be pushed back into the tyre compounding the issue.

Thanks for the invite, your only a couple of hrs. I'll email you.

...I wanted to chime in here and let you guys know that the "Lip Skid" product does help stop the wheel pant from being pushes back into the tire. They fit very close to the nose of the wheel pant and will carry a tremendous load. This location only allows the wheel pant limited movement when stressed or is hit from the front or bottom. Please see video link below (view the seventh video). Thanks Allan...:D
http://antisplataero.com/Videos.html or see this You-Tube clip;
http://www.youtube.com/watch?v=De2Q3je7k3w

http://i550.photobucket.com/albums/ii419/allannimmo/Image006.jpg

rocketbob
09-26-2012, 11:30 AM
Then Bob knows of a pilot who has flipped TWICE. Come on folks. You want to use that as justification that the nose gear is a horrible design that is just waiting to nail you?


Absoultely. The nosegear should be structurally strong enough to withstand poor technique, within reason. I'll bet there has been millions of landings on our strip as it is busy with a flight school and a lot of those same Cessnas can tolerate poor piloting.

This thread and none of the conversation would be occurring if the gear were strong enough in the first place.

MrNomad
01-03-2013, 07:53 AM
Bob:

Once again, allow me to thank you for all of the assistance and guidance you provided during the rebuild of the O-360 we installed in the RV6A. It has 80 hours and continues to purr along thanks to the ideas and suggestions we got from you.

Barry

Ron Lee
01-03-2013, 01:01 PM
This thread and none of the conversation would be occurring if the gear were strong enough in the first place.

Or people understood its limitations and avoided inappropriate landing surfaces.

One pilot with two flip-overs?

sglynn
05-19-2014, 10:14 PM
So after reading this very long thread, and being in the middle of building my RV-7A nose gear I want to implement the best modifications to date.
Therefore, are these 4 plus 1 modifications the best things to do to the nose gear:
1) Nose Job from Antisplat
2) Tip Skid from Antisplat
3) Bearing modification from Antisplat
4) Matco axle mod
5) Practice super pilot technique. Land on the mains, keep weight off nose gear by keeping stick back, no hard breaking, watch for crummy runways, beware of grass runways.

Do these all go together? Is Matco axle compatible with Bearing mod from Antisplat?

thanks

MauiLvrs
05-19-2014, 11:02 PM
Do these all go together? Is Matco axle compatible with Bearing mod from Antisplat?

Without 5 ... 1-4 may not mater.
With 5 ... 1-4 likely doesn't matter.

Read what Bob said.

Has anyone here instrumented a nose gear (i.e., strain gauges along the forward and aft gear surfaces) to looking at loading, load rates, deflections, etc.?
That sounds like actual engineering ... Think that Van's has done that...


The problem is that most RV pilots graduate from learning to fly on Cessnas and Pipers which obviously have much more forgiving nosegear designs.
...
So my recommendation for any RV pilot who wants to spend some money to improve safety is to start by spending it on some quality transition training with a reputable RV instructor. That could be a very beneficial and illuminating exercise.
What Bob says...

One could put a 152 nose gear on an RV and take away 60 HP to make up for the weight.

paul mosher
05-20-2014, 12:13 AM
The 152 gear may be stronger but Cessna bolts them to the firewall. Not unusual for them to come off when wheel barreled on landing. I bought a 182-A project that had the nose gear ripped off.

zilik
05-20-2014, 08:06 AM
Therefore, are these 4 plus 1 modifications the best things to do to the nose gear:
1) Nose Job from Antisplat
2) Tip Skid from Antisplat
3) Bearing modification from Antisplat
4) Matco axle mod
5) Practice super pilot technique. Land on the mains, keep weight off nose gear by keeping stick back, no hard breaking, watch for crummy runways, beware of grass runways.

Do these all go together? Is Matco axle compatible with Bearing mod from Antisplat?

thanks

My $0.02 worth of advice. I assume you have the latest and greatest gear leg and fork from Vans.

All the Antisplat stuff can't hurt except in the weight department. Keeping the tire inflated to 50psi and treating the nose gear with respect will go a long way too. But you have to acknowledge that no matter how many mods, etc, nothing will save the gear if the hole is big enough.

pa38112
05-20-2014, 09:42 AM
The anti-splat wheel/bearing modification and the Matco axel are two different approaches to the same issue - it is one or the other. Pick one.

Dmadd
05-20-2014, 09:46 AM
I'm kinda late to this discussion, but I'm wondering if anyone in the "A" community has suggested retracting flaps as soon as your on the ground. It will give your elevator much more authority and you'll be able to fly the nose wheel to a much slower speed...
If I missed it somewhere in the nine pages before this post, I apologize...:-)

Dennis

flyboy1963
05-20-2014, 10:18 AM
Dennis, hard to stay current on all 36 pages......
some have suggested we try to identify the 'smokin' gun' by collecting data, but it's not easy.
I just wanted to respond that 'many' of the nose collapses, or flips, apparently occur at much lower than landing speeds, so the focus on technique, while admirable, will not 'fix' the problem.
Aircraft TAXIING have flipped, at perhaps 10 mph, just enough energy to cause the tuck 'n roll .....it appears!
Experienced pilots with great technique have been bitten while taxiing across an uneven pavement seam. How do you avoid that happening?
I slow to a crawl when transitioning from one colour of pavement to another, but let's face it, a 1" high chunk of anything acts as a pretty good wheel chock with a 12" diameter tire up front.
3" deep gopher holes or ruts? expect trouble.

rightrudder
05-20-2014, 10:58 AM
A good scan of the surface while taxiing is probably the best defense?use the trike gear's forward visibility to your advantage. Treat a suspicious pavement seam as you would a big speed bump in a lowered car. And keep the 5-points cinched snugly, just in case you miss something. :eek:

RetiredRacer
05-21-2014, 04:33 PM
..... would be the first line of defense!!! Keep the weight off the front wheel as much as possible and that includes Dmadd's suggestion to raise the flaps.

Our 9a has rarely seen sealed runways. Some backyard strips we land on are so rough if you don't have your belts tight, you are going to hit you head on the canopy!! But the front wheel is off the ground for as long as the elevators can hold it off (take off and landing). And then keep the stick hard back at all times to reduce weight on the front wheel while taxing (except taxing with strong wind from bedind :D ).

We have the "nose job" fitted, the "Berringer" (spelling??) front wheel and axle mod and the wheel pant raised as much as possible. I believe it is important to have no friction and the spinning mass as low as possible so the front wheel can "spin-up" with least drag as possible and this helps reduce deflection on the front leg as it touches down. I would NEVER fly without the front wheel pant on!!!

Hope this helps.