[s_tones]

I fly a 1976 Archer.
Have been (again) considering the RV7A build.
For a number of reasons, I greatly prefer the trike over tail wheel.
I have just reviewed the NTSB reports linked through Dan C's site.
Looking through all the 6A,7A,and 9A reports I can't help but notice that if you take out the nose wheel collapse events there's not much left!
In other words nose wheel collapse is a substantial source of accidents (generally resulting in overturned airplanes with minor injuries) for these "A series" aircraft.
I find this very disconcerting and can't help but wonder if there isn't something on the horizon in the way of improvement in this situation at Van's.

I consider myself a fairly adept pilot and am always working to make my landings the best they can be. Still, like everyone, I have off days occaisionally. It's unsettling, to say the least, that a poor landing that would be well tolerated by, say, an Archer, could result in the destruction of the aircraft or worse.

I have flown in these planes and I love them. I think the build would be a total gas. But this one thing is really hanging me up.

S_tones

 

[Bob Axsom]

It requires care but not much really

I flew Archer N8304L for 22 years and it is a wonderful airplane. The RV "A" models are less tolerance of poor landing technique because there is no oleo strut on the nose, or main gear either for that matter. You are also going to be limited on payload, etc. but that is another story. Castering nose gear does not have to accommodate a heavy, draggy, round strut that extends in flight when unloaded and a sissors to maintain stearing control etc. Not only must you land an RV reasonably clean with the nose in the air but if you lose a brake you have a significant ground handling problem. Even the new Cessna appears to be headed in this direction for performance reasons.

I think you are doing the right thing to consider this decision very carefully and except for the RV-12 I would not expect to see any performance degrading modifications.

Bob Axsom

 

[s_tones]

Sooo...

Thanks Bob. I have to say I really love the Archer and have about 400 hours in 'em so far. But, I'm sure you'll agree that the RV puts the beast to shame in most respects (cargo carrying excepted)

Soooo....
How bad is BAD (landing)?
I can't imagine that RV flyers are necessarily just the worlds best pilots.
(No offense!)
But we're all human. Can you land that sucker flat and a bit hard once in a while?
Do you guys just grit your teeth with each landing or what?

S_tones

 

[pierre smith]

Saves

Hi guys,
There's nothing wrong with the design of the tri-gears. What I see as most of the problem amounts to one of two things and also a combination of the two.

1) Not landing the airplane in a nose-high, stalled or nearly stalled condition.

2) An inability to salvage a botched flare and bounce with the airplane nosing over into a dive and little or no correction as the nosewheel comes down first.

Technique, or lack thereof is the culprit. These airplanes are pussycats to land if it's done correctly (the way you were taught, or should have been).

A sure way to preserve the nosegear is to hold the stick back upon main gear touchdown and DO NOT suddenly let the stick forward and let the nose slam down. It seems to be a habit for some guys and it is really easy to overcome. I tell most of the transition guys who come here that they are going to have to ratchet their flying technique up a couple of notches and show more finesse than in the spam cans they're graduating from.
Regards,

 

[chaskuss]

I fly a 1976 Archer.
snipped
I find this very disconcerting and can't help but wonder if there isn't something on the horizon in the way of improvement in this situation at Van's.
snipped
S_tones

Vans has made an upgrade. The U shaped fork which connects the gear leg to the tire's axle was recently redesigned to allow more clearance between the front of the fork and the ground. This was discussed within the past 2 months. One lister even posted photos showing how the early and late style nose forks compared.
Charlie Kuss

 

[ProCoach]

The best insurance you can have to protect the nose gear is a tailwheel endorsement. Every plane should be landed as if it were a taildragger. (right, Pierre?) Once you learn how and why, your A series plane will likely provide better short field performance than the TDs because you can land at a greater AOA. This maximizes landing performance and nosewheel protection.

Like almost everything else in aviation, the machine (nosewheel) is better engineered than it's pilot (training/technique).

 

[CraigH@KRPH]

The best insurance you can have to protect the nose gear is a tailwheel endorsement. Every plane should be landed as if it were a taildragger. (right, Pierre?) Once you learn how and why, your A series plane will likely provide better short field performance than the TDs because you can land at a greater AOA.

VERY good point! My tri-gear technique improved dramatically after several hundred hours of tailwheel flying.

 

[Bob Axsom]

But we're all human. Can you land that sucker flat and a bit hard once in a while?
S_tones

Short answer - No you can't. If you do not land the plane properly you will eventually hurt it.

Bob Axsom

 

[svanarts]

From what I've read the nosegear collapses seem to come from nose gear oscillations after a particularly bad bounce, or hitting a chuck hole or some such. The nose gear starts to oscillate fore to aft until the fork digs in and curls up the nose gear. I've read that a wood or fiberglass rod bonded to the nosegear can effectively dampen these oscillations and thus reduce the likelihood of a nosegear collapse. The redesign of the fork so that it doesn't dig in as easly is probably going to help the most.

 

[s_tones]

thanks for all comments

I appreciate all your responses to my query.
I hope that I am able to embark on this project at some point in the not so distant future. I really cannot imagine a more fascinating or rewarding journey than building and customizing one's own aircraft.
I guess I will have to come to terms with this one issue....that is that an RV may not forgive pilot shortcomings that my Archer would suffer gladly.

S_tones

 

[Kyle Boatright]

One unusual thing about Van's nosegear is that many of 'em have a fore/aft oscillation even after a good landing on a paved runway. I'd say the oscillation is an inch or so under normal conditions on a normal runway at certain speeds. Not all -A's exhibit this behavior.

I don't remember seeing this kind of thing with Grummans (which have a simlar gear, IIRC), nor have I ever seen this behavior with any other type aircraft.

Is there any anecdotal evidence that there are runway conditions (texture, bumps, etc.) which could amplify this behavior enough that it would be a problem?

 

[David-aviator]

The redesign of the fork so that it doesn't dig in as easly is probably going to help the most.

It will help, but what will help most is a full aft stick at touch down, holding it, and staying off of soft terrain.

I flipped one on an engine out landing and know for sure river bottom sand will eat your lunch. Full aft stick means nothing below 20 knots. The airplane seemed all but stopped when it went over. One guy with tail wheel experience said it too might have gone over.

The Archer, with its big fat nose tire, might not have.

dd

 

[Bob Axsom]

Good thinking

I appreciate all your responses to my query.
I hope that I am able to embark on this project at some point in the not so distant future. I really cannot imagine a more fascinating or rewarding journey than building and customizing one's own aircraft.
I guess I will have to come to terms with this one issue....that is that an RV may not forgive pilot shortcomings that my Archer would suffer gladly.

S_tones

That is a sober and very good conclusion. Not only will you enjoy the process and the product but what it will do for you goes way beyond the obvious. Enjoy the adventure.

Bob Axsom

 

[pierre smith]

....that is that an RV may not forgive pilot shortcomings that my Archer would suffer gladly.

S_tones

The RV will give you so much more enjoyment that you won't even notice it's shortcomings, if any. Your Archer may gladly "suffer" pilot shortcomings but it has a lot more shortcomings than an RV, IMHO

 

[jonbakerok]

Come on.. it's not that bad

Short answer - No you can't. If you do not land the plane properly you will eventually hurt it.

Bob Axsom

I agree, if you habitually abuse it, you will eventually break it. But everyone has a bad landing once in a while.

I'll admit to having pancaked my 6A a few times, especially during the first few hours when I was getting used to the high sink rate. The plane's sturdy enough to survive your learning how to fly it properly.

In fact, I had one REALLY bad landing once where I hit so hard that the nose slammed down and catapulted me up into a bounce that had me headed back down nose-first into the pavement. I firewalled the throttle and it just levitated out of it. If I'd pulled a dumb stunt like that in my old Cherokee, the same thing would have happened but there would have been no recovery. I wound up with a scuff on the nose pant but no other damage.

It's a flimsy design, but it's not made of glass. You just need to treat it that way.

 

[cruzer]

Again, the truth of the matter is, the landing gear on old blue has had its share of problems. The first nose gear it was equipped with failed early in the aircrafts test flying program. It has had several other nose gears installed along the way, not all due to failure but testing different designs of gears. Vans N666RV may have over 4000 hrs on the tach but the airframe has had the entire emp. changed out, motor mount replaced, main gears reworked and numerous other repairs. To use it as a base example of having held up well over the years is subject to interpretation. PD

 

[amed]

e-mailed Van's

A couple of months ago I sent an e-mail to Van's about this very subject. I received a cursory "blow off" reply.
I've since deleted the e-mail, but the reply basically said that, One can suffer nose gear failures in any airplane, even a Cessna. Furthermore, RVs have fewer incidents than all other "certified" aircraft combined. (Duh, there about ten trillion other aircraft out there compared to a relative handful of RVs!) He also mentioned that Van's Aircraft produces a safe aircraft and that if Van's Aircraft discovered an unsafe condition, they would take the necessary steps to correct it... bla bla bla!
Needless to say, taking the time to e-mail Van's on this subject was a waste of time, and gave me virtually no comfort in my decision to purchase an "A" model RV.
Do I still plan to purchase an RV-9A? You bet I do! Am I still concerned? I perfer to say that I will have a healthy respect for the RV nosegear. After reading a zillion posts on this website, I've noticed that some people tend to behave like the "Drive By Media" and pile on a subject or concern. (Yes, I'm guilty as well)
I think it's probably not as big a deal as some of us make it out to be... That's my 2 cents...

 

[L.Adamson]

Do I still plan to purchase an RV-9A? You bet I do! Am I still concerned? I perfer to say that I will have a healthy respect for the RV nosegear. After reading a zillion posts on this website, I've noticed that some people tend to behave like the "Drive By Media" and pile on a subject or concern. (Yes, I'm guilty as well)
I think it's probably not as big a deal as some of us make it out to be... That's my 2 cents...

I've been watching RV "A"s landing in Ut. for over 12 years now, and have yet to see a collapsing nose gear from any RV owner that I personally know. And there is lots of them around here.

Although, I'm well aware, that a few nose jobs have had problems, it's certainly not something I've been worrying about! FWIW, Van's did come out with a new upgraded and heavier duty nose gear leg for the 6A, since I bought the kit in '96. I have the replacement.

BTW- A 9A with C/S prop and 160HP (even 150hp) is perfect for those Utah mountains!

L.Adamson

 

[444TX]

Attending a small grass strip fly-in this weekend an RV6 owner
and I were watching numerous RV trike and Cessna takeoffs and
landings. I mentioned the poor techniques used by ALL the pilots.
At first he disagreed ,but when actually paying attention was
suprised. He knew several and considered them to be competant
pilots.

Not one pilot had up elevator on the takeoff roll. Several were
actually using down elevator holding the nose on the ground.

Every pilot pulled the nose up at rotation. The nose wheels did
not leave the ground before rotation.

Every plane landed in or the nose was dropped into a three point
attitude. The nose wheels were not held off the ground.

I am sure that not all nose gear failures are caused by pilot technique,
but from what I have witnessed many likely are. Like earlier posted,
a tail dragger rating would be a great asset. If you can land/takeoff
a tricycle consistently correctly in all conditions then getting a
taildragger rating should not be too difficult. The techniques
used to fly a taildragger are same ones used in the trike.

I prefer tailwheel planes and feel comfortable in all conditions thru
the limits of the plane. I personally would never feel the same in RV
nose wheel planes off pavement. Talking to many RV trike owners
they too are worried off pavement or will never fly into nonpaved
strips.

Are there problems with the trike gear? No terrible problems, but
limitations that one must consider. There are limits with both types.
Landing in a sandy river bottom will likely flip or badly damage either.

George Meketa
RV8 740 hours, PA-12 25 hours (just purchased 3 weeds ago),

 

[Bob Axsom]

Not one pilot had up elevator on the takeoff roll. Several were
actually using down elevator holding the nose on the ground.

Every pilot pulled the nose up at rotation. The nose wheels did
not leave the ground before rotation.

Every plane landed in or the nose was dropped into a three point
attitude. The nose wheels were not held off the ground.

George Meketa
RV8 740 hours, PA-12 25 hours (just purchased 3 weeds ago),

It is incredible to me that an RV-XA pilot would operate as described here but that may explain why there are some operational failures. My elevator is up and pitch trim is for up elevator before the throttle is opened for takeoff and that nose comes off - RIGHT NOW! As I roll down the runway I can feel the lift assuming the load and I adjust back pressure to retain a possitive nose up but not excessive attitude. As the plane lifts off I crank out the nose up trim to maintain the desired indicated airspeed for the climb. On landing I roll it in on the mains every time and that doesn't mean get it to a unconsiously excessive angle of attack above the runway and let it sink in on the mains either. I even hold up elevator in the taxi until I get off the runway. It does take a few landings to adjust to the visual picture and the handling characteristics but the plane will handle that just fine as you "A" pilots have said. I land on grass if I have to or I know the surface is good but I do not go out looking for it.

Bob Axsom

 

[clarkefarm]

Another casualty

I fly an RV-9A off a farm strip which has a bit of seal and plenty of not so smooth pasture. I lent my plane to an Ag pilot and his loader to get home for the night when the fertilizer spreading job went a bit longer than expected.

On his return all was OK until he was about 10 yards from the concrete hangar apron when he cut the corner a bit and ran the nosewheel into a slight depression.

To my horror it grabbed and appeared to buckle sideways a bit before flicking forward and grabbing again. The front of the wheel pant was badly damaged and the internal brackets clamped by the wheel bolt were fractured. A prop strike must have been very close.

The depression was quite gentle being about 4' across and 3" deep in the centre. The gouge mark in the hard soil was about 6" long - pretty much on the lip and the level ground beyond the hole. There was a second smaller gouge about 8' from the first.

I was watching all this from the apron and although I have read the posts, could not believe my eyes.

The taxi speed was not excessive and although I did not see the elevator position at the time of the damage, had noted that the pilot was careful to hold full up elevator while taxiing the day before. In any event there was very little power or speed so elevator position was probably not a big issue.

On reflection I think that the accident was due to depression being just the right shape to dip the aircraft's nose and then catch the nose gear on the lip as it sought to rebound. I had previously been worried by more acute irregularities in the soil surface but am impressed by the ability of the gear leg to skitter over bumps and small holes while holding the fuselage level.

I will probably replace the gear leg and fork with the newer short leg and modified fork to gain an extra inch of clearance for the nut. What I would also like to do is to substantially strengthen the front of the wheel pant so that it would act as a skid and hopefully prevent the castor nut from grabbing.

Anybody have any other remedies ?

Regards to all.

Rupert Clarke

 

[ProCoach]

Anybody have any other remedies ?

Put the little wheel in back... where it belongs.
(just a joke) Sorry you're going through this!

 

[burgundyja]

how many ground loops are there compared to nose wheel colapse?

 

[ProCoach]

Collapses are on the design. Ground loops are on the pilot. ... here we go again...

 

[clarkefarm]

I take your point about the small wheel belonging to the back but always thought that I would get away with the nose wheel at airfields.

I am sorry that I can't post a picture of the "hole" because it would really worry a lot of people with nose wheels.

BTW a friend with a 9A also destroyed his front wheel pant at another airfield and couldn't even find the spot where it happened. He is well known for being super careful and taxiing slowly. Maybe slow speed does not allow the front gear leg to vibrate and release from undulations/bumps well ?

 

[terrykohler]

Take a close look at the clearances between wheel fairing and ground, and wheel fairing and tire on any "A" model. It doesn't take a very deep pothole to take the load entirely off of the wheel and transfer it to the fairing, which ain't gonna roll. At that point, the geometry of the front gear looks a little like a vaulting pole being planted in a pit. Either the gear leg remains intact and allows the plane to rotate on its back (unlikely), or the gear leg collapses and drops the nose to the ground followed by a ponential nose-over.
Likewise if the wheel to fairing clearance is nil and the tire loses pressure to the point of interference when the wheel expands during ground contact. Similar result to above, where you go from low rolling resistance to pole vaulter.
Use good soft field technique (at all times). Make sure you have a minimum of "finger" clearance between tire and fairing. Make sure tire pressure is correct. Avoid rough or unknown fields. I think this sums up many of the past posts.
Terry

 

[fodrv7]

Auto Loading.

As I said on another post, the nose gear leg on an RV-XA (stole that term from Bob, but it's a good generic term.) doesn't just deflect backwards but as much DOWNWARDs. Look at the angle of the fork.
So as it deflects it will load up more and more.

There is a pattern here of large deflections occuring at VERY SLOW speeds (as witness by people watching aircraft taxi) and I assume that is because at very low speeds up elevator is ineffective and the nose gear cannot be unloaded.

If you need to cross a known rough section you might be better off pulling the stick hard back and giving it enough power to cross the rough with the nosewheel clear of the ground.

Pete.

 

[vlittle]

I posted this on the site about a year ago. Since then, my skidplate design has been field testied in an actual pothole, resulting in abrasions to the nose cone bottom, but no failure. Even though the graphic says polyester resin, I used epoxy.

Design details at http://www3.telus.net/aviation/flying/RV-9A/Tips.html

Vern Little

 

[Captain Avgas]

I will probably replace the gear leg and fork with the newer short leg and modified fork to gain an extra inch of clearance for the nut. What I would also like to do is to substantially strengthen the front of the wheel pant so that it would act as a skid and hopefully prevent the castor nut from grabbing.

Anybody have any other remedies ?

Rupert Clarke

Rupert, because you have posted the pix of the indentation that caused your nose gear damage on another forum I have taken the liberty of posting them here.

It is important for nose gear RV builders to understand that at taxi speeds, even minor ground undulations can be most dangerous.

And in your case it was undoubtedly a very minor undulation. Of course this is not the first time a builder has reported serious nose gear damage resulting from a slow taxi situation. Those who are in denial about the extreme fragility of the Vans nosewheel design always point to landing and take-off technique. But quite a few nose gear failures have now been reported at slow taxi speeds.....surely this points to design limitations rather than pilot error. There are many who believe that, poor pilot technique aside, the Vans nose gear design is an over simplification of a complex structural requirement.

In answer to your question re a remedy. My suggestion would be to instal the new raked forks and then modify the nose wheel fairing to follow the upward rake of the forks. This will increase the ground clearance in the crucial frontal area of the fairing. In my opinion it would be better to increase ground clearance rather than keep the same clearance and beef up the fairing.

I would suggest that if some-one wanted to sell a modified nose gear pant that increased frontal ground clearance to take advantage of the new raked fork design they would be on a winner.

 

[Walt]

That's precisely what I did to the NLG...

I opted to install the new fork on my old style leg (had to cut an inch of the thread off) and then cut the bottom of both the front and aft fairings up about an inch. I glassed them back in flat on the bottom to provide maximun clearance and you can hardly notice the difference just by looking at it but it gave me at least another inch of ground clearance compared to the original. I also have plenty of room between the tire and fairing on all 3 tires. To prevent any tire issues up front I intall a new 8 ply tire and tube every year and run 35 psi in it. I also run goodyear FCIII on the mains and love them compared to the originals (wish they made one for the nose)!

 

[fodrv7]

Goodyear

I also run goodyear FCIII on the mains and love them compared to the originals (wish they made one for the nose)!

Walt,
What sort of improvement do your see on the Goodyears and would it be applicable to a taildragger.

Pete.

 

[gmcjetpilot]

Carbon fiber

Anybody have any other remedies ?

Wrap the gear leg with carbon fiber, at least 1/2 way up from the skinny end? The gear leg should deflects less. To be more effective you need to physically build up the gear leg outer dimension. May be the fairing can be integral and structural, verses just having the fairing as a lose sleeve the gear leg sits in.

We do that with the main gear don't we, gear leg stiffener? Yep In fact stiffeners on the mains may help the nose as well, by not bouncing around and interacting with the nose gear. The more stable the gear platform the better.

Think of it this way. The gear leg deflects. If the leg was bigger, stiffer, say infinitely stiff, than the wheel and fork would not deflect and dig in. The down side weight, cost and ride harshness. Also possibly more load may be transferred to the support structure in a hard landing.

 

[Captain Avgas]

I opted to install the new fork on my old style leg (had to cut an inch of the thread off) and then cut the bottom of both the front and aft fairings up about an inch. I glassed them back in flat on the bottom to provide maximun clearance and you can hardly notice the difference just by looking at it but it gave me at least another inch of ground clearance compared to the original. I also have plenty of room between the tire and fairing on all 3 tires. To prevent any tire issues up front I intall a new 8 ply tire and tube every year and run 35 psi in it. I also run goodyear FCIII on the mains and love them compared to the originals (wish they made one for the nose)!

Hi Walt, would it be possible to post a couple of pix of your modified wheel pant. I would be really interested to see what they look like.....as I'm sure others would. I understand what you've done but I'd just like to see the aesthetics.

Also, have you noticed any speed change with the modified wheel pant.

 

[Walt]

I'll try to get a couple of pics today and post them, I was going to check the air today anyway in all the tires as part of my pre S/F insp. As for the question on the main FCIII's I find that I can do my impression of a carrier landing now with no tendancy for the plane to bounce, a much firmer feel and landing. They also grab the pavement tenaciously and slow you down much better. A remarkable difference in landing performance IMO. This im my 3rd set of tires and they are holding up much better than any of the others (2nd set was a Michelin) so I can easily justify the higher cost. The landing performance is so much better I'd use them again even if they didn't last as long.

 

[Ron Lee]

Tires don't make the landing....

Superior piloting skills do. After my three squeaker landings today it must be the later. However, I will check to see which brand main tires I am using.

 

[Walt]

I'll try to get a couple of pics today and post them, I was going to check the air today anyway in all the tires as part of my pre S/F insp. .

Some pics of the modified NLG fairing...

 

[Captain Avgas]

Some pics of the modified NLG fairing...

It's a really intelligent mod Walt...and the fairing still looks good (maybe better).

Have you paid any noticeable price in terms of speed.

Incidentally I can't for the life of me work out why Vans increased the ground clearance of the nose nut...but didn't take advantage of it by increasing the ground clearance of the kit supplied fairing accordingly.

 

[clarkefarm]

New front wheel pant ?

Thanks Bob for posting the images.

When I ordered the new "shorter" front gear leg and modified fork Vans mentioned that they now have a new front wheel pant with inbuilt brackets. Apparently it is split down the middle, front to back, and is slicker. I ordered one so hopefully it will finish "higher".

If not, I really like Walt's modification.

Stiffening the lower section of the leg would certainly be worthwhile as I have a strong recollection of the bottom of the leg bowing backwards and allowing the rear of the fork/wheel to lift relative to the castor nut.

Rupert

 

[Captain Avgas]

Thanks Bob for posting the images.

When I ordered the new "shorter" front gear leg and modified fork Vans mentioned that they now have a new front wheel pant with inbuilt brackets. Apparently it is split down the middle, front to back, and is slicker. I ordered one so hopefully it will finish "higher".

If not, I really like Walt's modification.

Stiffening the lower section of the leg would certainly be worthwhile as I have a strong recollection of the bottom of the leg bowing backwards and allowing the rear of the fork/wheel to lift relative to the castor nut.

Rupert

Rupert, when you receive the new wheel pant would you please come back to this thread and report if it has in fact been redesigned to improve ground clearance.

I'm not so sure about stiffening up the gear leg. Without a non linear finite element analysis it would really be "experimental". My guess is that it would simply transfer additional loads back to the gear mount which might have other structural implications

The answer probably lies in a complete revamp of the design by Vans. Perhaps in future they will do the 2 place nosegear similar to the RV10 which I hear has a stiffer gear leg and a dampening system at the top (although I've never seen one).