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8 landing gear bolt torque

DMFenster

Well Known Member
Sanity check - The two PITA bolts have torque specs called out. I get that. Question is - The remaining bolts get torques to the spec consistent with their size - correct?
 
Let me put this another way.... :)

In the 8 there are 2 bolts inside the gear towers - I get those.
There are other bolts which hold the gear on that the torque specs are not specifically called out. Are these torqued to the specs consistent with the bolt diameter?

Thanks all,

Dave
 
Correct

Yes, the 2 PITAs are 240in/lbs, and the others follow std diameter spec torque.
Enjoy!
 
Gear nuts with epoxied wrench-ends?

Can anyone speak from experience about how they torqued these bolts if they modified the nuts with epoxied-on wrench ends?
For those scratching their heads, a little explanation?.I read and followed a post that showed how some guys cut off the end of a wrench, glue it to the nut, and install inside the gear tower. This, purportedly allows you to easily re-torque these PITA nuts from the bolt-head side, instead of spelunking into the crowded gear towers, where the nut with the glued-on wrench end, which still has a small "lug", remains jammed in place. Of course this will invalidate the specified torque value.

My question: how do you recalculate a proper torque value? TLAR? A certain percentage above what's specified? Should you lube these close tolerance bolts so they turn easier?
I'm almost ready to turn my fuselage upright to install gear, and have been wondering about this technique.
Thanks, guys.
 
I do it with a wrench I made like this:



and a second person on the torque wrench underneath, not ideal torquing the bolt but it is what it is :eek:
 
I use the NAS1804-6 nuts with the bolts in from the top on Grove gear. I was able to use the Fairings Etc fairing but the nuts did require a mod to the fairing essentially protruded 1/4-1/2 inch. Modified the fairing with a ridge that is the size of 1/2 a hotdog bun.
 
Can anyone speak from experience about how they torqued these bolts if they modified the nuts with epoxied-on wrench ends?
For those scratching their heads, a little explanation?.I read and followed a post that showed how some guys cut off the end of a wrench, glue it to the nut, and install inside the gear tower. This, purportedly allows you to easily re-torque these PITA nuts from the bolt-head side, instead of spelunking into the crowded gear towers, where the nut with the glued-on wrench end, which still has a small "lug", remains jammed in place. Of course this will invalidate the specified torque value.

My question: how do you recalculate a proper torque value? TLAR? A certain percentage above what's specified? Should you lube these close tolerance bolts so they turn easier?
I'm almost ready to turn my fuselage upright to install gear, and have been wondering about this technique.
Thanks, guys.

What I did was measure the torque required to turn the bolt before it got tight. This presumably is a measure of the friction torque that is required to turn the bolt. I added that torque to the torque specification. Assuming the added friction under the head of the bolt to turn it when it is tight is about the same as the friction to turn a nut, this should be about right. The wild card is if the bolt turning friction changes when the bolt is tight, because of parts alignment. So, if anything, my technique is still a bit on the low side, but not off by as much as just using the torque spec without correction.
 
How I did it

Bought 2 1/4" drive 9/16" sockets. Then ground them down every-which-way-but Sunday. Made them shorter and narrower. The I mangled my hand into the gear tower and got the sockets on each nut. Then I fed a long extension with a universal down onto each socket through one of the lightening holes. Put a 1/4" drive on each extension and my buddy torqued down from the outside while I held both drives. It would be a pain for the initial torque to try to switch the socket back and forth because they are torqued in 5 in-lb increments. Worked out fine.
 
Flash light, mirror, Two wobble heads and two extensions, and a 7/16 twelve point socket... With two people I can retorque the gear tower bolts in < 2 minutes.
 
Flash light, mirror, Two wobble heads and two extensions, and a 7/16 twelve point socket... With two people I can retorque the gear tower bolts in < 2 minutes.

Mmmm?Mine are 9/16th. This might be why it's easier for you. (?)

Upon further review?I popped the nuts out of the sawed-off wrench ends, and installed per plans. I did have to unscrew a small bolt in the aft, left section of the gear tower in order to get a socket on the big nut located there.

Now?I need to find a monster torque-wrench so I can 'set' the PITA nuts. I want to do those first, because if the gap is too small on the outer bracket, I have to remove EVERYTHING. For this reason, I will tighten, but not torque, all the other nuts, initially.

BTW, the HUGE, single bolt on the inside bracket calls for 450-500 in-lbs, according to my book. Can anyone confirm this big number, please? :eek:
 
Re-torque Tecnique?

I am at my condition inspection. In retorquing the prop, you loosen everyone and then step-wise re-torque to spec (fixed pitch composite). With gear bolts do you loosen first? Seems like that would call for new lock nuts. Am I correct that it is proper to put on the torque wrench and check that is tight enough without loosing to make sure it's not too tight?

Thanks.
 
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