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Aluminum socket head cap screws for landing gear?

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Aluminum socket head cap screws for landing gear?

Old 09-06-2015, 02:04 PM
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ltc
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Default Aluminum socket head cap screws for landing gear?

Has anyone tried using M4 aluminum socket head cap screws to install landing gear in a plane?
The thought was that in case of a landing (grass, pothole, maybe even a pancake landing, etc) where excessive stress was applied to the landing gear block in the fuse, the bolts would shear, protecting the fuselage from possibly ripping out the gear blocks.
Under normal operation/landing, the forces should not cause the bolts to shear/break (I was going to ask a mechanical engineer at work to check my numbers and perhaps run a simulation or calculation)

Or it's just a stupid idea and I should just use Secraft washers and a steel M4 bolt as usual.
Old 09-06-2015, 06:25 PM
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Anthony-RCU
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Hi Lucky,
Interesting theory but were will the landing gear go when the bolts shear? Usually, up and back putting the wheel pants through the bottom of the wing or tearing the sides of the fuse. Landings are mandatory and take offs are optional.
Old 09-06-2015, 11:56 PM
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Malcolm H
 
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Yes, the bolts will shear, the gear will rotate through the fuz openings doing lots of damage and then rotate up and pierce the wings damaging them too. Better add a little carbon re-inforcement to the gear block mounting imho.

Malcolm
Old 09-07-2015, 05:37 AM
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I have used them for weight savings, Quite a few grams especially if you have 3 per leg. I have never had them sheer even with rough landings. I have no issue using them.
Stuart
Old 09-10-2015, 12:38 PM
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Jason Arnold
 
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I agree with what everyone else says about shearing and damaging fuse sides and wings.
Titanium screws are a better option in this area. Saves lots of weight without compromising strength.

Cheers,
Jason.
Old 09-15-2015, 12:03 PM
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apereira
 
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I use 3mm bolts with 3mm conical anodized washer from Kyosho for Buggies, works good,I guess they could shear in a rough landing, on the other side, if you shear the bolts, most likely there will be damage to the fuselage if it impact the ground hard enough to shear the bolts.

4mm bolts in F3A is pretty much overkill nowadays, no matter if they are aluminum.

Just my opinion of course.

Regards
Old 09-20-2015, 03:01 PM
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Originally Posted by Jason Arnold View Post
I agree with what everyone else says about shearing and damaging fuse sides and wings.
Titanium screws are a better option in this area. Saves lots of weight without compromising strength.

Cheers,
Jason.
Ti is nice and shaving a few grams of bolt weight is good, but why not shave several ounces from the whole undercarriage set-up?

A different design approach was required and I have it. The design has been refined making it easier and simpler to install in any fuse. Uses no conventional mounting wood and practically no hardware to mount. A single 4-40 or 2-56 screw is all that needed to hold each leg in place.

I've discussed the technique is a couple of my threads
Old 09-23-2015, 01:40 PM
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I have used alum bolts on several planes for weight savings. Haven't sheared or deformed any yet, and most of my flying is from grass fields that most people would call "rough".

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