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Old 06-28-2017, 12:47 PM   #51
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Simon,

Rod ends should have a witness hole and you must engage the threads to cover that hole. Use a small piece of safety wire to check for minimum engagement.

I'm curious about the wing chord and the aileron chord dimensions. If it's not too much bother I'd love to have those dimensions. Thanks.....


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Old 06-28-2017, 01:04 PM   #52
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Bill, thanks for the hint. Unfortunately there are no such holes. Since I'm going to lock the rod end with the nut and use some locking varnish I thought this should be enough. Plus: Even if the rod end might become loose, it won't move since the other side is still locked. If the next side should unlock, too - the travel will still be the same, as long as there are enought threads left on both sides. This is why I'd like to have as much threads covered, as possible...

No problem at all, I'll throw the rule at my wing and give you the numbers.


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Old 06-28-2017, 01:23 PM   #53
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Ah, I see now, the rod ends are male threads. Any witness hole would have to be in the pushrod itself. How deep are the threads in the pushrod? No need to go any deeper than that on assembly.
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Old 06-28-2017, 02:34 PM   #54
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For now only 5 full threads are in the pushrod. I would feel more comfortable with 8, but this way the pushrod seems to be too short. Guess I'll have to take a closer look as soon as the wings are test mounted to the fuselage including stick.
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Old 06-28-2017, 04:46 PM   #55
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How many threads are in a standard nut of that size? That would be my minimum engagement.
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Old 06-28-2017, 05:10 PM   #56
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Yep, standard practice is one thread showing minimum. I see no need for more, just dead weight.
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Old 06-28-2017, 08:14 PM   #57
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Simon
The minimum thread engagement is 1.5 times the major thread diameter.
I guess you have 3/8" thread diameter,so the minimum engagement should be 9/16"
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Old 06-28-2017, 09:11 PM   #58
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Lots of ways to look at this. An AN665 fork has threads about 1.75xD but AN315 & AN365 nuts have much less than 1.0xD. If you look at a REPB female rod end the witness hole is at a consistent 5/16" no matter what size the thread is!

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Using 1.5xD is very safe but I wouldn't feel bad about having less engagement. Unlike an AN665 these parts see relatively small loads.
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Old 06-29-2017, 07:09 AM   #59
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Thank you guys for your participation. Most of it are exactely the thought I had, too.

I'd also like to follow the rule of thumb with 1.5 times the 1.5 times the major thread diameter, but unfortunately the pushrod seems to be too short to apply this rule.

I'm in contact with Jay Womack, he'll remove his fabric in ~1 month and might take some pictures for me. We'll see whats wrong with my pushrod system. Maybe it's just me that did a fault on assembling.

Yesterday evening I applied the sealer to the leading edges, today I'll so some reinforcement work with super slim fiber glas on all the areas where pushrods go through the plywood.

I measured the wing and aileron: wing incl. aileron has a chord of 46.8" the aileron itself has 10.5", so roughtly 22.5% of the wing are aileron.
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Old 06-29-2017, 02:11 PM   #60
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How deep are the threads in the pushrod? Those are not standard AN parts welded to the ends so they could be anything in terms of thread depth.

I assume a typo there, did you mean 36.8" and 10.5"?

Thanks Simon!
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Old 06-29-2017, 04:54 PM   #61
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About the 1.5 times rule of thumb,yes i think,is may be to much and sometime impossible to apply.I found that on AURORA web site.
For my push rods,i will use REP3M6A (that i bought to Kris) with a thread of 1.313" long,or REP3M6-2N with a thread of 3/4" long.For the first ones,i can use the 1.5 times rule with the bolt in,for the second ones,no

http://www.rbcbearings.com/aero-pdfs...RE_MS21151.pdf
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Old 06-30-2017, 09:45 AM   #62
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The threads go really deep into the pushrods, I would guess about 1". The inserts are open at the end, so no problem with screwing it in too far.

I have the GMM-3M-670 AURORA bearings, ACS #05-01639 with only .75" thread lenght. Theoretically this should be enought.

I'll finish the wings first, then assemble the airframe the first time to be sure about the aileron deflections with the stick, and the decide on what to do. Your info is really valuable, thank you guys!

...and then I'll start the fuselage salvaging.


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