Last Frontier

Hello all, new to the forums and this is my first post--
I'm building a .20 scale Great Planes J-3 Cub, and I'm converting to a super cub on floats (building and forming the new cowl from scratch-as none are available anywhere... but that's for another post).

I'm using the GP .20 scale float kit and they will be finished in fiberglass. I really like the looks of the sea commander float kits, but I'm not willing to pay the $ at this point to get them. My local hobby store is extremely well stocked and they carry some streamlined aluminum tubing in the right size for my application for a much more reasonable price. My question is, how should I tackle connecting the tubing at the joints, and how do I mount to the floats and fuse? Suggestions and advice are welcome. Even better would be some detailed pictures of how some of you have done this. The sea commander website doesn't have close up shots of how the tubes are mounted to the fuse, although they do have some nice pics of the brackets at the float end.

(The attached image is one found on the sea commander website of Balsa USA 1/3 scale Super Cub on Sea Commander 1/3 scale EDO 2000 series floats by Murray Marley-- it is used to help illustrate my question)

michpittsman

My Feedback: (11)

I would build the struts using 1/8 music wire, bend all the pieces to the right length and slide the streamlined aluminum tubing over the wire, using silicone glue to hold it in place. The aluminum tubing will not be strong enough to carry all the load you need to carry...JIM

cf-drg

My Feedback: (1)

LF I have used the K&S streamline tube for floats, and it is to thin walled... Any slightly hard landing and the prop is into the floats( bent struts A-Plenty )...What I do now is take solid alum, grind and file it into a streamline shape... Haven't had a problem yet.. The other option is to find a thicker walled tubing,, SeaCommander has the thick stuff, you might be able to just get it, from them..As for the GP floats they are a good wood kit, but don't forget to add spreaders to them..

leedsflyer

SeaCommander uses aluminum square stock inserted into the tubing. It is bolted in place with through bolts. Another method that I have seen is inserting aluminum flatstock into the tubing and sandwiching it between wood to fill the interior of the tubing. This sandwiched assembly is pinned in place or can be through bolted like the aluminum stock.

alasdair

I always use flat alloy bar, eighth by half an inch, from a hardware store, or piano wire. Of the two I come to prefer piano wire.
I used K&S streamline tube for a tailplane strut once on a flying boat. I flattened it, bent and drilled it for a fixing bolt, but it fatigued and cracked after a while. Too thin walled for structural loads as the others said. Can be used to pretty-up the load bearing member inside.
Alasdair

Last Frontier

Thanks for all the good advice guys. I decided to go with using 5/32" wire inside the tubing. This method seems to work great for the struts and the spreader bars. A little 30 min epoxy helps make a nice bond between the wire and tubing. I imbedded the spreader bars inside the floats themselves and it turned out to be a very rigid and sturdy system. My next step is to create the struts and mount them to the floats. I will post some pictures when it's all done!

jetranger-RCU

My Feedback: (1)

tubes - go to the auto parts store and buy the strips made to go on the door edges of your car. They are stream line like the al tube slip on and cut to size and cheap some come in colors

Last Frontier

Okay, step one is almost complete. The floats are finished with fiberglass and painted. You can see from the picture how the tubes are imbedded in the floats themselves. The 5/32" wire is inside the tubing and bonded with epoxy. The wire is secured inside the floats through a solid hardwood block and collar as an anchor. All of it is then bonded to former and outside sheeting with epoxy.