N916K

N916K

Well Known Member
Has anyone converted an "A" to a taildragger? I know it's possible but I would like to talk to someone that has actually done it. Please no nose vs tail dragger comments, I'm not trying to stir anything up, there's a place for that discussion.

Thanks
Cam

PS
I know what parts are needed so I don't need a parts list, thanks.
 
Van did it

What model? Finished plane or one being built?

Sure it can be done. Will it be cheap and easy? No.

You will have to buy some very expensive steel parts from Van. As far as installing the parts, it is dependant on if the plane is under construction or finished. The engine mount switch is a no brainier, but the tail wheel support on the TD will be a little challenge (pain in) to install on a finished RV-A. I am sure it can be done, even if you have to drill out lots of rivets.

The RV-8 I am sure has a whole different set of issues.

"A" to TD:
Remove: engine mount, nose gear, main gear and main gear fittings
Replace: New engine mount with new main gear legs
Add: tail wheel assembly: support fitting, stinger, fork, wheel and steering chain

Of course you will have to re-route brake lines. G
 
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Also, don't forget that you'll need to plug the holes in the forward bottom skin for the gear leg's on the -A models (7 and 9).

Also, do you have steps? Are you going to leave to steps or remove them? There's another plug job if you don't want them there.

Oh yeah...you would also want to patch the slit in the cowling for the nose gear leg.

I would think you would have to at the very least remove the aft deck and the second-to-last bulkhead (forget the number). Remember the two vertical bars that the h-stab attaches to? Well, those things gets tapered for the -A models but not for the taildraggers, so you would want to drill those out...which would mean it would be just as easy to remove that entire bulkhead.

I think it could be done. The biggest expense (I believe) for the conversion would be the new engine mount.
 
The plane would be my 9A. It's a slow build so I know what went into building it and what parts are different, I'm just looking for someone that has done this conversion. Info like, is it worth removing the rear bulkheads or just try to modify them in place, leave the "A" gear weldments in place or remove, things like that.
 
Cam,

Let me know if you need some pictures of the tail section.

Not having built a -9A I think the conversion will be straight forward. You may have to remove a bunch of rivets in the back to get the TW weldment in place and cut the 714 (I think that's the number) skin to allow the weldment to poke through.

Radomier and I had this discussion the other day and I think you could leave the "A" gear weldments in place and just cover them with a fairing. If you want to remove those weldments there are two aluminum replacements that you will need. These tie the spar carry through to the side of the fuselage and bolt on, just like your wedlments. The engine mount is only money, not a big deal. As someone mentioned the brake lines will need to be routed through the firewall and there is a stiffener that will need to be fabricated and riveted in place. Other than that I don?t see much difference.

What made you see the light and want to switch to a TD?
 
PS. I have heard of one -9A that was converted to a -9 after the nose wheel collapsed but I don't know who or where. Check with Van's, this might just be an RV legend.
 
N941WR said:
What made you see the light and want to switch to a TD?
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I would really like to keep it a nosedragger. The ground handling is wonderfull and I can stuff the plane in anywhere I want, wind really isn't an issue. It's the design of the nosewheel that I have the biggest problem with. I only called Van's twice with questions during the construction of my slowbuild, the second call was "Is the nose wheel gear suppose to move side to side like this, and why isn't there a spacer between the wheel bearings?" Didn't really get much of an answer from them.

I lifted the nose off the ground the other day to remove my nose wheel fairing after 170 hours of use because all four aluminum brackets had cracked. Of course you can't really tighten the aft two brackets because there is no spacer between the wheel bearings. So while the wheel was off the ground I checked the breakout force. That was right on the money, but the nose gear had quite a bit of slop in it at the engine mount. I haven't been able to tear into it much more but it seem like the bolt on top of the nose gear is wollowing out. That was my concern when I called Van's, looks like it did pretty much what I thought it would. Now maybe I built something wrong in the first place but I don't think so. I do fly off of grass strips quite a bit. Some aren't very smooth. I always do soft field take and landings no matter what the surface is like, grass or pavement.

Don't take this as a dig on A's. I really like the plane with a nose wheel, but I'm thinking that my flying style may not fit the design of the A as well as I had thought. I still believe my Grandfather's (flew in three wars) quote about taildraggers is true "They fixed that problem".
 
Nose gear leg wobble

So while the wheel was off the ground I checked the breakout force. That was right on the money, but the nose gear had quite a bit of slop in it at the engine mount. I haven't been able to tear into it much more but it seem like the bolt on top of the nose gear is wollowing out.
Click to expand...
When I built my -6A, I too noticed a slight bit of play at the upper bolt. I had the same concern about wollowing, so I replaced this bolt with a close tolerance AN bolt. It was a real pain to get it in, but in 3 1/2 years and 350 hours, it never loosened up a bit. This could be an option for you, if it's really the only reason you're considering changing her to a TD.
Good Luck!
Bill Waters
 
rvpilot said:
I replaced this bolt with a close tolerance AN bolt. It was a real pain to get it in, but in 3 1/2 years and 350 hours, it never loosened up a bit.
Click to expand...

Bill

Using a slightly larger bolt is something I've considered. I think I'm going to pull the gear leg today and see what's going on with it.

Cam
 
The answer is

Cam:

The answer sounds like you need to just fix the nose gear strut play and fix the fairing brackets with better, stronger ones or leave the nose fairing off. Going to a TD seems like more work than necessary.

As far items like, spacers and fairing bracket cracks, it sound like there is room for improvement. GO to steel or thicker aluminum fairing brackets. The spacer thing and ability to tighten brackets I don?t understand, but all brackets need to be tight and the tire should not rub on the side of the fork or fairing at all. The fairing should be solidly supported. I built two TD's so I am not familure with the nose fairing.

As far as your flying style, it sounds like a 9A is perfect for you. Changing to a TD seems extreme if you are doing it because of the problems some other pilots have had with the nose gear and the few "flight test" phase problems you are having. It took me at least 200 hours to shake out all the little weak points on my RV-4.

I would by all means make getting the nose gear leg play to ZERO a priority. Also I would do everything you can to make sure the tire does not rub on anything (wheel pant fairing, fork). I would keep the nose wheel fairing off until you can figure a way to repair and/or improve the mounting of the fairing. If you re-install install new stock brackets, do so if you can figure a way to tighten the aft brackets. No doubt you know the gap between tire and faring should be generous. The loads on the fairing in theory should be low. Why 4 cracked brackets? [Shimmy loads, tire rubbing, ground impacts, preload brackets (fit), loose barckets (safety wire, Loc tight), deburr/break all sharp edges (stress risers)]

G
 
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gmcjetpilot said:
The spacer thing and ability to tighten brackets I don?t understand, but all brackets need to be tight and the tire should not rub on the side of the fork or fairing at all.
Click to expand...

The current nose wheel bearing design is:

axle bolt-fairing bracket-fork-spacer-bearing-nothing-bearing-spacer-fork-fairing bracket-nut

They have you use the axle bolt torque to set the preload on the bearings. Typically in this type of an instalation you would have a spacer between the bearings so you can just torque down the axle and not have it tighten down on the bearing. When everything is first installed it may seem like enough clamping force on the fairing brackets to hold them in place, but once the bearings break-in just a little the clamping force on the brackets quickly goes away. Now the brackets are free to move slightly, and the spacers begin to spin relative to the fork. This wears away the spacer and the fork, further reducing the clamping force on the brackets. You could keep retorquing the axle bolt, but the problem will never go away.

As far as the the gear leg play, I'm not real interested in finding out what happens if the bolt breaks. I'm pulling the engine tomorrow and plan on putting a tapered bolt in the gear leg. That should take care of any slop in the gear leg. I know just reaming it out to 3/8 then using a close tolerance bolt would be easier, but I'm in there and might as well use a bit of overkill.

I'll see how all that works then decide if I want to keep the wheel up front.

The new plane I'm working on only comes in a tailwheel so I'll have a TD one way or another. :D


Cam
 
Well the fun thing about an experimental is you can fix problems with you own design. So make up a spacer :) Install a bushing or close-tolerance bolt, and tighten it all up.
 
Try posting on the RV-7 Yahoo Group. There is a guy there that converted his -7A to a -7 and then back again. Can't remember his name at the moment.
 
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