Gear Leg Attach - All Metal Lock Nuts?

[RudiGreyling]

Hi guys,

I must be going crazy, yesterday I had too many nuts today I don't have enough???

I can't find the ALL METAL LOCK NUTS called out in the drawing to attach the Landing Gear to the Engine Mount? Searched the net and can't find the answer either... I only got some ordinary Nyloc Nuts in my brown bag of landing gear goodies.

What gives?

 

[pierre smith]

Dunno

Hi Rudy,
I don't know where they might be.........in a bag or box someplace Temporarily use nylon locknuts. They call for all-metal usually on all firewall forward nuts because of the heat softening the plastic in the other locknuts. Meantime either order or scrounge up some at a local airplane maintenance facility (Jan Smuts?)

Regards,

 

[vbpiper]

Nuts!

Rudi,
I can't help you with your question, but have you by any chance read the thread "How did you guys do this"? If not, might be worth a quick read before bolting on the engine mount.
By the way, love the videos!
Ward

 

[RudiGreyling]

Piere: Ditto, I also used the Nylocks tempory.
vbpiper: I did a lot of reading before bolting on the engine mount, but might have missed that thread, anycase the mount is on, engine to go on soon.

Anycase will send out a mail to Vans asking them about it, just thought the answer is available in the RV community rather than hold someone up with an important RV questions.

 

[GAHco]

Shear Application

From the looks of your picture the only reason the nut would need to be allmetal is the fact that it is within the engine compartment (forward of the firewall).

Without temperature to consider, the Nylocs would have worked as well as the Allmetal locknuts. The bolts are in a shear application and both the MS20365-524A (AN365-524A) and the MS21045-5 are rated at the same minimum tensile strength (125 ksi).

The Nylocks are however rated at a lower temp (250 deg F) and the Allmetal nuts are rated to the higher temp (450 deg F).

To find out even more about locknuts go to

http://www.gen-aircraft-hardware.com/template.asp?pagename=nutlock

Don't forget to download the Locknuts from our reference book, or better yet order our reference book and get all the info on our hardware!

These two pages that you will download have more than 60 pages of Govt and other industry prints boiled down to what you will see. The info that matters to the user, not the manufacturer.

Have fun!

 

[RudiGreyling]

Hi Guys, Thanks for the feedback, Vans got back to me pretty quickly with an email:

"...there is a mismatch between the kit and dwgs. You can use the normal AN365 type nuts in the kit. They don't get hot enough to require the all metal type."

Regards
Rudi

 

[RV7AV8R]

I noticed during my annual my nylocks had loosened and allowed a slight play in the gear legs. The play went away when retightened but I'm switching to all metal nuts on the gear leg!
John Adams

 

[terrykohler]

John:
I don't believe that fact that you used nylok nuts has anything to do with the loosening. The prevailing torque (torque required to overcome the lock) should be the same for both the all metal as well as the nylok. Each of these fasteners has advantages/disadvantages, some of which have already been mentioned. Because of the design of this joint, I would make an annual torque check part of my condition inspection. Tom Brink is correct in that the bolt is in shear. By torquing the joint, you're trying to add a little clamp load at the top of the gear tower. This is to eliminate movement in the joint and thus movement of the gear leg.
Terry
RV9A
N323TP

 

[RV7AV8R]

I agree torqueing this bolt is now part of my annual and should be for A models as well. In the taildragger, the nylock is in a hot area and could loose its holding power so I am switching to all steel lock nut for this reason.
John Adams
Seattle

 

[RV7AV8R]

As an additional important data point. Today I replaced the nylocks with all metal lock nuts. When I was taking the nylocks off I noticed they turned easy. I tried and was easily able to unscrew them with my fingers after the initial tension was off the nuts! I have 200 hrs on these nylocks and they clearly where not holding anymore. My rv7 is a Taildragger so the gear leg bolt is in the heat and the nylocks are not taking the heat well. An A model would have the same issue with the nose wheel if it uses a nylock.
Unless you off load all the weight on your gear you may never notice this problem.
John Adams

 

[dan]

Rudy, I think the original plans called for nylok nuts there. The finish kit probably still comes with the nyloks. Just a guess, could be wrong. Looks like maybe they updated the DWG but not the hardware. You might have to source those nuts yourself.