RV tipple over update from UK

[petehowell]

I think it was RV-9er Vern Little that made this mod. He should chime in soon.

[zilik]

Was this landing or takeoff

[mannanj]

Friends of mine in Lockhart, TX. built what they call their "jock strap", a rounded steel plate covering the big nut holding the nosewheel fork on. Hopefully it will skid along the ground keeping the nut from digging in and prevent a tip over.

[Baja_Traveler]

Originally Posted by petehowell

I think it was RV-9er Vern Little that made this mod. He should chime in soon.

A quick search found the Thread

[osxuser]

Look at the Grumman AA1/5 setup. There isn't any regular problem with them flipping over, yet they have a similar setup. It's all about execution of the design. Van's is simply a SPRING with no real dampning at all. This means it will flex up to a point, then bend. TO make it worse, it doesn't have enough ground clearance in the front pivot, due both to a poor design, and a too small tire.

Cessnas, Pipers and grummans all use 5.00x5 nosewheel tires, that helps out in these situations where you hit say, a small pothole. In an early -a model, that would be enough to flip you. In the current, it still gets your attention and a little deeper one can still cause problems.

Grumman's nosewheel leg has a dampner built into the fire wall and a couple of other details that escape me at the moment, but help contribute to stability.

Quick and dirty solution to the -a models? A 5.00x5 nosewheel fork.... with a new wheel fairing of course. Anyone interested in that kind of mod?

[the_other_dougreeves]

Originally Posted by Finley Atherton

Would anyone who has changed from the old to the new style nose fork care to offer an opinion as to whether this has increased the safety factor on rough surfaces? Are there any known cases where the new style fork (with it?s one inch extra clearance) has contacted/dug into the ground ?

Fin 9A

I'll second that. The fact that so many nosewheel airplanes have accidents like this is troubling. I am interested in a A model because of the simplicity of landing it and lower insurance - there's a reason why nosewheel airplanes are in the majority. However, this isn't exactly making the case for the A model. The good news seems to be that all of these accidents are survivable, but ....

Originally Posted by osxuser

Quick and dirty solution to the -a models? A 5.00x5 nosewheel fork.... with a new wheel fairing of course. Anyone interested in that kind of mod?

Yep. A larger nosewheel would help, but I suspect that the longer-term solution is a different design to the nosegear.

There is a lot of discussion about these accidents being caused by improper technique. Whether or not that is the case, I want an airplane that is somewhat forgiving. RVs are about performance, but if I spend all that time working on an airplane, I want it to be robust. The nosegear certainly seems to be a weak point.

[jcoloccia]

The problem, as I see it, isn't that things break if you don't have good technique....it's that the plane flips and puts the occupants at risk. There's really no reason that the gear can't be designed with a couple of shear pins towards the top of the gear. Instead of tucking under and flipping the aircraft, the gear would simply collapse. Would that be better? I dunno...it'd be different and could possibly be a whole lot for the plane and the occupants. Could also make things worse.

Just throwing it out there...

[Bob Brown]

The Cessna 182 has a reputation for nosewheel damage too. In fact, after owning a few of these great heavy haulers and looking at many more over the years...I'm not convinced that MOST 182's have collapsed their nosegears over the years. I'll grant you most of these have not been while taxiing, but poor landing technique but nonetheless the failure rate of Cessna's HEAVY nosewheel arrangement indicates that shy of a major weight gain in the front end, it might be a difficult task to design much performance improvement (without a huge weight gain) for the -A models.
As others have said, technique plays a huge role in all of this...as does luck (we have the whole planet to land on and roll into a gopher hole or something similar). Sitting on the ramp watching "A-model" RV's land all day I am struck by the fact that about 75% of them put all three wheels on the runway at the same time...exactly what Mike Seager (and Van himself) preaches against. I think most (not all) of the nosewheel failures are rooted in excessive descent rates, too much speed on rollout and failure to keep the stick in the full aft position while taxiing.

[koda2]

As the builder of '96 (older) -6A, the photographs of the 7A tipping over are distressing. I could not find the video but here is what I see from the 4 photos.
The a/c is a later RV-7A which should have the upgraded nose gear leg and looks like it has the later nose fork.
A number of factors show that it was traveling at a very low groundspeed, i.e. multiple reference points in the photos, the way the props are bent, the proximity of the initial prop strike in the sod and final resting point, the fact that at the second photo both occupants have already braced themselves for impact, and that the impact vectors are almost completely vertical, being absorbed mostly by the dome of the canopy, which appears to have broken, and the roll bar, which did not fail, and which forced the longerons and fuselage skin to crumple. Furthermore, there is no apparent subsequent disturbed ground and the rudder position has not changed, which it should have, after impacting if the plane had slid. Also the primary point of failure appears to be the nose gear leg at a point just above the fork since it is bent a full 90 degrees aft, but the rest is not visible. So, my best guess is, the aircraft was taxiing at a relatively slow speed, was arrested by the sudden stoppage of the nose gear, and flipped over.
If this kind of thing is still happening since the new gear leg has been deployed, Vans needs to do a systematic review of the RV incidents involving nose gear failures, and, unlike some of the alternative engine vendors, who supposedly have not been admitting their problems, publicly disclose what the findings are. If not Vans, the FAA.
BTW, I have already bought the new beefier nose gear leg (U-603-2) which was $175 plus $40 freight. Now it looks like I will have to check out the new fork too.
Oh, yeah, and not land on grass when (if) my plane is built.
Dave A.
RV-6A

[Steve A]

In the first photo, isn't the nose wheel fairing the white object under the right wing. I view this accident as landing with too much forward pitch and slamming the front wheel into the ground, causing the nose wheel fairing to fly off. That is what is shown on the first photo, I think.

Steve Anderson
RV 7A Finishing