P

prkaye

Well Known Member
The main axle bolt for the nosewheel is an AN6-60. I'd like to put something a little longer in and raise the head out with washers so my tow bar has more to bite on and won't slip off the bolt head so easily.
Neither spruce nor vans has AN6 bolts any longer than -60.
Does anybody know a source?
 
Don't the plans suggest attaching the tow bar to the hex screws that hold the bracket in place? I've been using that and never had any issues with tow bar slipping off.. (and I have to pull the plane with the lawn mower to get it into the hangar)...
 
No longer axle bolt needed, don't use the axle bolt.

I use the Wag-Aero Tow Bar:
RV-A Series Aircraft Deluxe Towbar M-340-026 $49.95
http://store.wagaero.com/advanced_se...ption=1&page=2

and I installed these:

RVa Tow Pin Kit
P/N 04-pkRVa
each $ 15.00

Scroll to the bottom of this page:
http://www.bogert-av.com/whats_new.php

This combo works great!!!!

2009-10-03%20003sm.jpg
 
Last edited:
I plan to use the axle bolt (i've already drilled the holes in my wheel pants). Another local builder has reported (and I've experienced this a bit with the limited movements I've done with my towbar in the shop) that it's easier to steer with the towbar on the axle bolt. He wishes he'd put his holes in the wheel pants over the axle bolt instead.
I'll order the bolt through GAHC... thanks!
 
prkaye said:
Another local builder has reported (and I've experienced this a bit with the limited movements I've done with my towbar in the shop) that it's easier to steer with the towbar on the axle bolt.
Click to expand...

Been moving Tri-gear RV's around with tow bars for many years...I have found just the opposite to be true.
 
...I have found just the opposite to be true
Click to expand...

I think it can be geometrically proven that it should be easier to steer with a towbar on the axle bolt. The axle is further from the pivot-point on the gear leg than is the allen bolt, so the lateral force required to deflect the wheel (for steering) from the axle will be smaller (torque = force x arm).

The other consideration for me is that it wouldn't work as well for me to locate the holes over the axle bolt, as these would lie right on the seam between the two wheelpant halves.
 
Last edited:
Reversed thinking !

prkaye said:
I think it can be geometrically proven that it should be easier to steer with a towbar on the axle bolt. The axle is further from the pivot-point on the gear leg than is the allen bolt, so the lateral force required to deflect the wheel (for steering) from the axle will be smaller (torque = force x arm).quote]

That is not correct! You will be placing the tow bar further back, thus shortening the tow bar arm (the distance from the pivot point of the wheel fork, to the handle bar of your tow bar will be shorter), so you will need more force to turn it!

Regards, Tonny.
Click to expand...
 
Do yourself a favor and use the hex bolts for the tow bar. I used the axel bolts at first also and it was definitely harder to turn/move the plane. Also, the tow bar slipped off the bolts a couple times when I was trying to turn the plane and damaged the wheel fairing. I suppose the slipping issue could be helped with the longer bolt, but it's still not the ideal situation.

Also, make sure you have the new style fairing mounts that don't require you to remove hex bolt AND the axel to remove the fairing. The newer style only requires you to remove the front hex bolt which is MUCH easier. I re-configured my nose gear after 6 months of fighting the old setup and am very glad that I did.

Greg
RV-7A
 
You will be placing the tow bar further back, thus shortening the tow bar arm (the distance from the pivot point of the wheel fork, to the handle bar of your tow bar will be shorter),
Click to expand...

Ah yes... good point....
 
Also, make sure you have the new style fairing mounts that don't require you to remove hex bolt AND the axel to remove the fairing
Click to expand...

Huh? I've had my fairing (wheel pant and gear leg fairing) on and off several times during fitting without removing either the allen bolts or the axle...

in light of all your comments I may glass over the holes I've drilled in my wheel pants and do them over the allen bolts instead. I just need to determine if I can make it work given that these are located right at the seam between the two wheel pant halves.
 
Last edited:
prkaye said:
Huh? I've had my fairing (wheel pant and gear leg fairing) on and off several times during fitting without removing either the hex bolt or the axle...
Click to expand...

My original nose fairing mounts (purchased from Vans ~2005) consisted of 4 individual U-shaped Al mounts similar to the ones used on the outside of the main gear where the fairing is bolted to the axel nut. Two of these mounts were used on either side of the fairing and held by passing the axel bolt through the mount. The other two u-brackets were forward on the fairing and held by the hex bolts. This setup required me to remove the axel and the two hex bolts to pull the fairing off.

The new brackets that I purchased from Vans (~Aug '08) were one piece on each side of the fairing. The rear of the bracket has a slot that fits over the axel and the front of the bracket has a hole that is secured by the hex bolt on the forward side of the nose gear fork.

Sorry I don't have pictures that I can post.

Greg
RV-7A
 
By "Hex bolt" do you mean "allen screw"? Or is there an even newere design than the 2008 model you mention?
Mine is has the allen screws towards teh front, but these do not need to be removed to take the fairing off. THe fiberglass fairing slips over the brackets and attaches to them with screws into nutplates on the brackets.
 
prkaye said:
By "Hex bolt" do you mean "allen screw"? Or is there an even newere design than the 2008 model you mention?
Mine is has the allen screws towards teh front, but these do not need to be removed to take the fairing off. THe fiberglass fairing slips over the brackets and attaches to them with screws into nutplates on the brackets.
Click to expand...

Yes, Hex Bolt=Allen screw in my post. Sorry if I confused you. Also, I riveted my brackets to the fiberglass fairing and drilled a hole in the fiberglass over the allen screw. This hole doubles as an access for the tow bar and removal of the allen bolt. Once the allen bolt is removed the fairing (bracket and all) slides right off.

It seems that you have used screws to attach to the brackets instead of riveting them permanently to the fiberglass. This certainly works, but riveting them and using the allen screw as an attach point eliminates extra visible fasteners on the outside of the fairing. Just my preference...

Greg
RV-7A
 
ah ok, now i see what you mean. The plans showed nutplates on the brackets, so that's what I did. Granted, it is a bit of a stretch to get that aft wheel pant over the bracket, but now that I've learned how to do it, it's no problem.

My final decision now is to use an AN6-66 bolt through the axle, with a self-locking castle nut and cotter pin. I'll build up the difference (almost an inch!) with lots of washers, making a really good thicknes for the towbar to bite on.

When I looked at where the holes over the allen screws would end-up relative to teh seam between my wheel-pant-halves, I just really ddin't like it. Plus, I've already laid up about 10 layers of reinforcement around my holes over the axle bolt.
I've ordered the AN6-66 bolt from GAHco.
 
Stik to the plans!

PRKEYE, you'r making a mistake and adding lots of weight, in the process! What is the problem with having the holes, for the tow bar, where the seam of the pant is? Me no understand.

Regards, Tonny.
 
you'r making a mistake and adding lots of weight,
Click to expand...

"Lots of weight"?? You think? Actually, keeping the CofG forward is going to be challenge for me because of my super light Catto prop, so a few ounces extra steel in a bolt will help... lots of extra weight to shift my CofG forward :rolleyes:

I don't think it's a "mistake"...lots of planes use the axle bolt for a towbar. I know one RV-7A builder who says he always uses the axle bolt instead of the allen key when the wheel pants are off. I really don't think this is a case where one choice or the other is a "mistake"... I think it's personal preference. I see no structural reason why the longer axle bolt should pose any problem.
 
Last edited:
Just to give you one more point of reference...a friend of mine bought a -6A that is hangared just down the row from me. He complained to me that his tow bar was too difficult to use. I checked out his plane and sure enough...the builder was using the axle nut for the tow bar. He corrected it and is now totally happy.

Trust me...you want every bit of leverage possible...especially when pushing the airplane backward. I would stick with the plans on this one. I'm still not sure what problem you're trying to solve by using the axle.
 
Hmm... the problem i'm trying to resolve is the position of that hole over the allen screws. It would be right over the flange where the two wheel pant halves joing together. The aft edge of the hole will be extremly close to the aft edge of the forward wheelpant. This will leave a very small flimsy bit of material between the aft edge of the hole and the aft edge of the forward wheel pant. Similarly, the forward edge of teh hole will be near the forward edge of the aft wheel pant. Basically the hole is not going to be nicely centered with adequate edge distance from either wheel pant half.
 
Last edited:
prkaye said:
Hmm... the problem i'm trying to resolve is the position of that hole over the allen screws. It would be right over the flange where the two wheel pant halves joing together. The aft edge of the hole will be extremly close to the aft edge of the forward wheelpant. This will leave a very small flimsy bit of material between the aft edge of the hole and the aft edge of the forward wheel pant. Similarly, the forward edge of teh hole will be near the forward edge of the aft wheel pant. Basically the hole is not going to be nicely centered with adequate edge distance from either wheel pant half.
Click to expand...

When the nose fairing is properly installed, the fwd edge of the hole is approx. 1/2 " aft of the split line. Because the aft half also has a 5/8 wide flange around the fwd perimeter, this gives a distance of 1 1/8" from the edge of the hole to the edge of the part. Multiple hundreds of flying RV's have proven this to be more than adequate.
 
Having just damaged my fairing because the towbar slipped off the axle, I'm definitely going to look at the bogart kit. I can glass over the holes in the fairing for the axle and enlarge the ones over the allen screws while I repair the fairing.

Regarding the longer bolt, if you still end up going that way, don't just add a bunch of washers. Do it right and make spacers. Remember, no more than 3 washers. In this instance, not only can a stack of washers 'work' rotationally and eventually wear, they also do not provide any lateral support where you will be towing your entire plane on. It may just be me, but I think taking care of that nosewheel axle is somewhat important...
 
When the nose fairing is properly installed, the fwd edge of the hole is approx. 1/2 " aft of the split line
Click to expand...

Well then I guess mine is not properly installed. On close examination I determined the holes actually straddle the split line. That's where things just seemed to naturally sit when I installed the wheelpant. One hole is actually about 1/4" forward of the other, so the pant is obviously not quite straight relative to the fork... I visually aligned my wheelpant when i installed it, but I guess something wasn't quite straight (maybe my nosewheel was turned ever so slightly). Not a big deal I think, since the nosewheel assembly pivots anyway and will naturally find the straightest configuration in flight... the offset will be so minor that I can't see it causing any problem for landings (the nosewheel being slightly off centerline).

Or is it worth getting a new nosewheel pant and getting it perfectly straight relative to the fork? It would be a pain trying to match drill this to the bracket now with the nutplates already installed in the bracket....

Your collective arguments have convinced me to abandon my axle bolt idea. Since the holes straddle the split, there is no edge distance issue, so I drilled those holes and am going to glass over the axle-bolt holes I had previously drilled. Unfortunately i wasted 50 bucks on an extra long axle bolt, but that's par for the course I guess.
 
prkaye, when I installed the new style pant bracket, I riveted it to the pant and reinforced it with epoxy and glass cloth. You could do the same and fill in any holes with glass cloth and filler, thus saving the expense of a new pant. Any extra, unused, drilled holes in the bracket will fill in with resin and actually assist in the bond. Ultimately, the pant should be removeable by just removing the front half and undoing the two hexhead bolts. The rear of the pant bracket is held in place by the axle bolt utilizing the spacer washers and just slips off the axle without loosening. I like this setup versus the old pant bracket as you can remove the pant without jacking the nose wheel up and disturbing the axle preload.

Roberta
 
Thansk Roberta, you're absolutely right. That's the beauty of fiberglass... almost anything can be repaired. I've started the fiberglass repair and modification you suggest, and now my brackets will sit exactly where they are shown in the plans. I wish I had thought to remove the brackets from the wheel before drilling the wheelpant the first time... much easier!
At most, I may have to buy a new forward wheelpant section, but that is inexpensive.
 
Last edited:
You must log in or register to reply here.