1/3 Scale J3 Cub Build
09-01-2009, 08:59 PM
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RE: 1/3 Scale J3 Cub Build
Hi Anthony...there is nothing I need specifically......if you have anything already scanned it just would be neat to have access to........thanks!...........Mike
09-04-2009, 11:37 PM
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RE: 1/3 Scale J3 Cub Build
Now I am begining to do the cabin trust and base for the landing gear. I'm going to try steel brake line and see how strong it is..... the price is right.
09-05-2009, 12:30 AM
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RE: 1/3 Scale J3 Cub Build
You know the plan says that the welding done is high temp. around 1200 degree silver solder. I know this stuff is expensive..... how strong? Well I would tend to think brazing or tig welding would be much better. I have both so I think I try tig welding it. It is very thin wall tube so we will see how good I am .I know to tig large stuff no problem I've never tried this small of tubing. I've seem my friend tig weld a beer can so I know it can be done with some practice. Does anybody know how Robarts make their gear?
09-05-2009, 08:07 AM
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RE: 1/3 Scale J3 Cub Build
Don,
I have the Robart gear on my 25% Cub, they are tig welded using thick wall steel tubing. IF you have a local hydralics supply house you can pick some up there. I purchased some from Cincinnati Hydraulics to build my 25% Waco tail wheel strut. I think they charged me about $3 a foot. Thin walled brake line will not be strong enough to weld up the landing gear legs in my opinion. you may get away with in in the fuse cage.
Here is a pic of the Robart installed on my Cub.
Anthony
I have the Robart gear on my 25% Cub, they are tig welded using thick wall steel tubing. IF you have a local hydralics supply house you can pick some up there. I purchased some from Cincinnati Hydraulics to build my 25% Waco tail wheel strut. I think they charged me about $3 a foot. Thin walled brake line will not be strong enough to weld up the landing gear legs in my opinion. you may get away with in in the fuse cage.
Here is a pic of the Robart installed on my Cub.
Anthony
09-05-2009, 09:34 AM
#83
RE: 1/3 Scale J3 Cub Build
The Robart is at least 1/16" wall, very thick for the small dia. I would try to measure it for you but I filled the exposed ends on my gear and there is now no way to measure the wall thickness. I know Khodges has a set of these gear sitting on his bench, you may want to send him a PM and see if he can measure them for you.
09-06-2009, 08:06 AM
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RE: 1/3 Scale J3 Cub Build
I cut the brake line to length for the gear on mine last week. The wall thickness seems like it will be ok to me. Each end of the tubing has steel strap welded to it which would help the strength on the ends. The longest section on the gear is about 10 inches or so. The tubing I have isn't the type which comes in a roll. It was in 6' lengths and pretty stiff when cut to short pieces.
09-06-2009, 11:47 AM
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RE: 1/3 Scale J3 Cub Build
Don........do the front landing gear fittings look to you like they are made to slip over the 3/8 truss before it's welded up? The plans make it look that way to me. Thanks..........Mike
09-06-2009, 10:37 PM
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RE: 1/3 Scale J3 Cub Build
Hi Mike
The small bracket in figure A welds to the bottom corners on the landing gear trust. I believe that the brake line tubing will bend on a hard landing. I took it back to the store and ordered some 4130 steel tubing .035 wall thickness. I am going to tig weld mine. The high temp silver solder just cost alot and I already have a Miller Tig welder.
The small bracket in figure A welds to the bottom corners on the landing gear trust. I believe that the brake line tubing will bend on a hard landing. I took it back to the store and ordered some 4130 steel tubing .035 wall thickness. I am going to tig weld mine. The high temp silver solder just cost alot and I already have a Miller Tig welder.
09-09-2009, 11:39 PM
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RE: 1/3 Scale J3 Cub Build
Mike
Aircraft Spruce has the 4130 steel tubing in all the wall thicknesses. I think .035 for the 5/16" dia and .035 for the 3/8" dia should be strong enough. You can always get a little thicker if you want.
Aircraft Spruce has the 4130 steel tubing in all the wall thicknesses. I think .035 for the 5/16" dia and .035 for the 3/8" dia should be strong enough. You can always get a little thicker if you want.
09-10-2009, 07:41 AM
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RE: 1/3 Scale J3 Cub Build
Hi Don.......... the freight to Norcal from Aircraft Spruce about killed me on two separate orders already. I bet you willcall your stuff from Corona? I got the silver solder from a welding supply here for 17 bucks a stick..........geez!!!.......Anyway, I have the lower truss done and some of the larger tubes with the straps over the brass tubing finished. Is the inner telescoping section from brass? If you could get some clear pictures of your truss front gear mounting brackets when you start them, it would really help. ........Mike
09-11-2009, 12:57 AM
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RE: 1/3 Scale J3 Cub Build
Oh, I got the solid rod at Osh hardware , they have a rack of tubes in brass, alum, stainless steel and reg steel. really better than the LHS! I use a piece of Stainless Steel For the sliding rod.
09-12-2009, 10:22 PM
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RE: 1/3 Scale J3 Cub Build
I am waiting for my tubing to arrive so I decided to build the other half of the stablizer. I added a few little extra blocks for the 6 hinges instead of 4 and use robarts instead of making the ones on the plan.
09-14-2009, 10:33 AM
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RE: 1/3 Scale J3 Cub Build
Frank
I click on NEW POST on the lower left of the last post, NOT FAST REPLAY at the bottom, when you do that a window opens , you click browse , go to your folder and double click on the picture you want, you do this over and over the little window has about a dozen lines for pictures. Then you wait for it to load and say OK , click OK then you are back at your post and you click OK their. You are done now and it posts.
What tube did you use for that cub cage?
I click on NEW POST on the lower left of the last post, NOT FAST REPLAY at the bottom, when you do that a window opens , you click browse , go to your folder and double click on the picture you want, you do this over and over the little window has about a dozen lines for pictures. Then you wait for it to load and say OK , click OK then you are back at your post and you click OK their. You are done now and it posts.
What tube did you use for that cub cage?
09-14-2009, 02:31 PM
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RE: 1/3 Scale J3 Cub Build
Hi Frank............the Cub looks good. If you get a chance, could you send or post pics where the metal work ties in to the woodwork at the lower windshield and the rear section It looks weird to me on the plan. If you could post the front section of the landing gear brackets, that would help too..............thanks..........Mike