Author Topic: Carbon Fiber Landing Gear Legs (Read 1858 times)

Chuck Matheny · « **on:** September 21, 2020, 10:34:28 AM »

I'm building a profile stunt plane that I expect will weigh 24 ozs or less. OS .15 Powered on 50 foot lines. Flown off grass with what I expect will be pretty gentle landing speeds.
I would like to make a couple LG legs out of C/F cloth. The LG will project from the underside of the wing. The LG legs will need about 4 inches of unsupported length, so I guess I need the "lay up" to be 1/16" thick to be strong enough.

My question is...would medium CA work..? Saturating 1 layer at a time and sanding before applying the next layer..?

Is polyester resin an option...?

Mike Alimov · « **Reply #1 on:** September 21, 2020, 01:00:48 PM »

Unless your goal is to immerse yourself in the world of composite technology, why not buy one of these (or similar) and cut the landing gear out with a Dremel cut- off wheel? I think 1.5 mm thickness should be about right.

https://www.ebay.com/itm/200-300-0-5-3mm-Black-Carbon-Fiber-Plate-Panel-Sheet-Board-3K-Twill-Matte-Weave/303603231445?_trkparms=aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20190917065201%26meid%3Dfdeeb3f2f7a446d099bac01a820179b5%26pid%3D100935%26rk%3D2%26rkt%3D12%26mehot%3Dco%26sd%3D223910571082%26itm%3D303603231445%26pmt%3D1%26noa%3D0%26pg%3D2332490%26algv%3DSimplAMLv5PairwiseWebWithDarwoV3BBEV2b%26brand%3DUnbranded&_trksid=p2332490.c100935.m2460

And no, saturating one layer at a time with CA is not a good idea. All layers need to be wetted out with laminating epoxy, pressed for 24 hrs, and then thermally post- cured.

Chuck Matheny · « **Reply #2 on:** September 21, 2020, 02:10:43 PM »

Thanks for giving me a look at those CF sheets.
I've been holding on to a yard of CF cloth so long I forgot why I bought it. I'd like to make use of it if I can.
If I remember correctly, didn't Burt Rutan use CA to laminate his wing spar in the Voyager..?

Mike Alimov · « **Reply #3 on:** September 21, 2020, 04:48:48 PM »

I haven't followed everything Burt did, but my friend built two Rutan kits: Quickie and Long Ez. No mention of CA; it's all epoxy, fiberglass and foam. Thermal post-cure by baking in the sun.

Why not try the CA method and share with everyone how that worked? I will be sharing my composite results as soon as I have something that works to my satisfaction.

John Leidle · « **Reply #4 on:** September 21, 2020, 07:38:13 PM »

I bet ya dollars to donuts you try CA & it will set up long before it saturates the Graphite. Sparky has a video someplace showing how he does it.
John L.

Chuck Matheny · « **Reply #5 on:** September 21, 2020, 09:36:43 PM »

Quote from: Mike Alimov on September 21, 2020, 04:48:48 PM

I haven't followed everything Burt did, but my friend built two Rutan kits: Quickie and Long Ez. No mention of CA; it's all epoxy, fiberglass and foam. Thermal post-cure by baking in the sun.

Why not try the CA method and share with everyone how that worked? I will be sharing my composite results as soon as I have something that works to my satisfaction.

What I recall are the "Satellite City" CA ads that showed Rutan using 55 gallon drums of that stuff for that build.

Chuck Matheny · « **Reply #6 on:** September 21, 2020, 10:29:29 PM »

Quote from: John Leidle on September 21, 2020, 07:38:13 PM

I bet ya dollars to donuts you try CA & it will set up long before it saturates the Graphite. Sparky has a video someplace showing how he does it.
John L.

The medium CA works real well on 6 oz FG cloth. Thin CA won't work, it "kicks" too fast and thick CA wont "wet out" the FG very efficiently. Dan taught me the CA /FG technique for "Down and Dirty" quick jobs. I have done this several times for engine cowls. The CA / FG composite is very sandable.
Today I used West Systems epoxy to make 3 layer plys of this CF cloth I've got. I blotted up the excess resin with paper towels and placed this "lay up" between sheets of plastic. I used fairly heavy weight for squeeze out more resin and to hold this mess flat. As it turns out 3 layers of this CF cloth measure .035" thick. I am surprised to see how much this fairly course cloth flattens out after it's been subjected to this process.

John Leidle · « **Reply #7 on:** September 22, 2020, 09:43:01 AM »

Chuck,
I can see me smoothing the CA into the roving strands & walking upstairs & driving around looking for a hobby shop that sells debonder with a set of landing gear stuck to my hand. I use CA in a small laminate for fiberglass cloth or carbon mat. Also when it gets spread out the CA fumes are overwhelming to me. I use epoxy myself.
Good luck , John L.

Chuck Matheny · « **Reply #8 on:** September 22, 2020, 03:02:57 PM »

Quote from: John Leidle on September 22, 2020, 09:43:01 AM

Chuck,
Also when it gets spread out the CA fumes are overwhelming to me. I use epoxy myself.
Good luck , John L.u ha

funny you should mention this because advise you get from professional body men / painters is that once you reach the stage you aren't bothered by the fumes....you might think about retirement.
My .035" thick lay up is pretty much cured and I am surprised to see how "springy" it is.
I really am tempted to use what I have here on this 20 oz plane.
What's funny about MODEL BUILDERS is this...is there more "peer pressure" against erring on the side of being TOO HEAVY,,?...or on the side of being TOO LIGHT...?

Curare · « **Reply #9 on:** September 23, 2020, 01:49:33 AM »

Quote from: Chuck Matheny on September 22, 2020, 03:02:57 PM

funny you should mention this because advise you get from professional body men / painters is that once you reach the stage you aren't bothered by the fumes....you might think about retirement.
My .035" thick lay up is pretty much cured and I am surprised to see how "springy" it is.
I really am tempted to use what I have here on this 20 oz plane.
What's funny about MODEL BUILDERS is this...is there more "peer pressure" against erring on the side of being TOO HEAVY,,?...or on the side of being TOO LIGHT...?

If it breaks, it's too light, if it doesn't break it's too heavy.

John Leidle · « **Reply #10 on:** September 23, 2020, 08:22:10 AM »

Chuck,
Many moons ago I was working late at night in the Summer heat, I dumped over a bottle of this CA with the cover off , spilled maybe an ounce on the work bench. Being this was thin CA it spread out fast when I tried to wipe it up the fumes hit me in the face burning my eyes. They were real sore for a couple days . So I don't spread out much of the stuff any more.
John L.

Chuck Matheny · « **Reply #11 on:** September 23, 2020, 10:11:51 AM »

Quote from: John Leidle on September 23, 2020, 08:22:10 AM

Chuck,
Many moons ago I was working late at night in the Summer heat, I dumped over a bottle of this CA with the cover off , spilled maybe an ounce on the work bench. Being this was thin CA it spread out fast when I tried to wipe it up the fumes hit me in the face burning my eyes. They were real sore for a couple days . So I don't spread out much of the stuff any more.
John L.

..but weren't you also in tears for a couple days because you had just wasted $5.95...? I don't know how we managed before CA...

John Leidle · « **Reply #12 on:** September 23, 2020, 12:23:41 PM »

Absolutely.

Author Topic: Carbon Fiber Landing Gear Legs (Read 1858 times)

Chuck Matheny

Carbon Fiber Landing Gear Legs

Mike Alimov

Re: Carbon Fiber Landing Gear Legs

Chuck Matheny

Re: Carbon Fiber Landing Gear Legs

Mike Alimov

Re: Carbon Fiber Landing Gear Legs

John Leidle

Re: Carbon Fiber Landing Gear Legs

Chuck Matheny

Re: Carbon Fiber Landing Gear Legs

Chuck Matheny

Re: Carbon Fiber Landing Gear Legs

John Leidle

Re: Carbon Fiber Landing Gear Legs

Chuck Matheny

Re: Carbon Fiber Landing Gear Legs

Curare

Re: Carbon Fiber Landing Gear Legs

John Leidle

Re: Carbon Fiber Landing Gear Legs

Chuck Matheny

Re: Carbon Fiber Landing Gear Legs

John Leidle

Re: Carbon Fiber Landing Gear Legs