SonexBuilders.net

I remember having read that, instead of using only one AN4 bolt to fasten the tail wheel titanium rod to the tail wheel mount, it is preferable to use 2 AN3 bolts.

If I use this mod from the plans, I have a couple of questions:
- what distance between the 2 holes should I use?
- should the holes for the 2 AN3 bolts be made with a 90 degrees lag?

Moreover, since the lower aft fuselage skin has a hole to reach the cotter pin and the nut which bolts to the single AN4 bolt, how difficult would it become to reach the 2 cotter pins and AN3 nuts?
Should I enlarge that small hole in the skin?

Thanks
Carlos
XENOS-B

Hi Carlos, I have never heard of any problems with the single bolt. Where it is located, the bolt is only loaded in shear and with only one bolt you know exactly where the load is going. If you replace it with two bolts you have no way of knowing how the load is being distributed. Depending on hole clearance and bolt fit, it could be that one of the smaller bolts will be taking most of the load. A more useful change might be to glue the tail spring into the fitting using epoxy. The fittings used to be made with pretty big clearance on the titanium rod so filling the gap would be useful. Loctite would be good but I think the clearance is too large for Loctite to work.

Peter

Thank you Pete

For your opinion.

I tend to agree with you, but would like to hear opinions from those who defend the 2 bolts solution.

Gluing the rod inside the mount tube seems to preclude the possibility of replacing the spring in the (low probability, I know) event of having to replace it.

Regards
Carlos

Carlos,

I don't think there is a real-world problem with using a single AN4 bolt to hold the tail spring to the mounting bracket or the tail wheel assembly to the spring. I can't think of any reports of this AN4 bolt breaking, and my feeling would be that if a user did experience a bolt failure then there is likely something else that contributed to the situation (a bur on the hole edge, oversized or out-of-round hole, etc).

There may be some benefit using two bolts to hold the main gear socket to the lower gear leg (these can wallow the thin-wall tubing of the socket), but even that is not a common problem. If the socket does loosen up around the bolt securing it to the gear leg you can repair it by welding a doubler on top of the existing hole and re-drilling to match the gear leg. You could even weld on a doubler before initial fitting as a proactive measure if you were concerned about operating off very rough terrain.

In all these cases there is no clear trend suggesting that modifications are mandatory to the main gear, tailwheel or bolts. Lots of users are flying with the stock setup and it has been working well for the majority of them.

Jeff

Carlos,

I used a taper pin for each end of the tailwheel rod. On my One Design, the bolt would loosen even with the nut tight and I replaced that with a taper pin. That solved the problem. I also had the same problem on the trim tab torque tube and the taper pin fixed that problem. So for my Xenos project, I went straight to the taper pin install instead of trying to retrofit later when the problem occurs.

I did not epoxy the rod in the socket. I used 0.005" SS shim material with a hole cut in it. It fits the full length of the socket. Tight fit so far.

I did use bolts per plans for the main gear rods. I'll probably regret that decision later. I have bought the taper pins for it just in case.

Rick Caldwell
Xenos 0057

Carlos...........you use a single AN4 bolt only on the FORWARD end of the tail spring.........just like in the plans.

But you use two AN3 bolts on the aft end to bolt the tail fork to the spring......(just like Van's has done for years).
The tail fork tends to "work" and wiggle a bit over time with only one bolt. The two AN3 bolts won't let that happen.

To repeat. ......install the single AN4 bolt in the fwd end inside the fuse......just like the plans spec. I use a fiber lock nut (no cotter pin) on ALL those bolts (again.......Van's method).

Gordon........Hummel 2400.....Onex 0024

I bonded mine in. If I need to remove it, I'll take the torch to it to weaken the bond and then pull it out.

Thank you guys

for all your answers.

They will help me make decisions.

Cheers
Carlos
XENOS-B

racaldwell wrote:Carlos,

I used a taper pin for each end of the tailwheel rod.
.........

I did use bolts per plans for the main gear rods. I'll probably regret that decision later. I have bought the taper pins for it just in case.

Rick Caldwell
Xenos 0057

Rick

Would it be too much to ask you which are the sizes of the taper pins you used?

For the tail wheel rod, can it be AN386-3-12A?

And what about the taper pins you bought for the main gears?

Thanks in advance
Carlos

Correction

For the tail wheel rod, can it be AN386-2-10A? (not drilled, to use with elastic stop nut)