dumb question--
But what is the tube diameter of the nose gear?
Tom
But what is the tube diameter of the nose gear?
Tom
Van's Air Force
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Year long discussion of "Another nosegear failure" -09/19/2010
- Thread starter rocketbob
- Start date
Jim Wright
Well Known Member
Jim Wright
Well Known Member
Nose Gear
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
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
tracker
I'm New Here
Check out this thread, reference youtube video -
http://www.vansairforce.com/community/showthread.php?t=64850
http://www.vansairforce.com/community/showthread.php?t=64850
tracker
I'm New Here
You might want to follow this thread as well.
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.
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.
Definite Solution
Here is the way everyone should land an A to stay out of trouble...
http://www.airliners.net/photo/Tipsy-T-66-Nipper/1882796/
Here is the way everyone should land an A to stay out of trouble...
http://www.airliners.net/photo/Tipsy-T-66-Nipper/1882796/
LifeofReiley
Well Known Member
Here is the way everyone should land an A to stay out of trouble...
http://www.airliners.net/photo/Tipsy-T-66-Nipper/1882796/
Yepper... That is the way it's done.
Anti-splat Mod for A Models
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.
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.
I just flipped my 9A
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.
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
Well Known Member
Sorry to hear that! I can't image how tramatic that would be. Glad everyone was ok.
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flyboy1963
Well Known Member
shouldn't we be collecting data?
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!
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!
Ron Lee
Well Known Member
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.
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.
He did say he was going a bit too fast, and not holding full aft stick.
Ron Lee
Well Known Member
Maybe a factor, but I doubt it was the root cause. The surface is the most likely causal factor in my opinion.
RetiredRacer
Well Known Member
Sorry, I do not entirly aree with that.
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
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
Well Known Member
Unfortunate Accident!
...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...
...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...
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PerfTech
Well Known Member
PerfTech
Well Known Member
..Try this; https://vimeo.com/46060731 I also fixed the link in the original post! Thanks, Allan....
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wow .
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.
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.
AlexPeterson
Well Known Member
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
I'm New Here
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
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
Well Known Member
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.
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.
PerfTech
Well Known Member
....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
rocketbob
Well Known Member
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
Well Known Member
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,
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apkp777
Well Known Member
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)
Anyone who thinks this is not a design flaw is foolish. (IMO)
Does it?
"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.
"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.
nose wheel
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.
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.
N941WR
Legacy Member
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.
Let's be careful out there .... even with Anti-Splat
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
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
Finley Atherton
Well Known Member
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 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
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Ron Lee
Well Known Member
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.
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.
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.
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
Well Known Member
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?
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
Well Known Member
personal failure.....comments
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
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
sorry...long post
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) 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?
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) 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?
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