My buddy has a sig airplane, dont know what one, but he made it go from a single engine to a twin engine. He just built up nacelles onto the wing. Anybody do this before? Anyone have any good tips on doing this? I'm thinking of building another airplane before the flying season is here, and was thinking of doing a twin, but the conversion.

Thanks

Well the first thing that comes to my mind is how in the heck is this gonna balance.
Granted the 2 engines would be smaller than the one but still - the total weight of both would necessitate that the nacelles would have to place the engines farther back than the single engine design was in order to have the CG come out in a spot where you could move components around to achieve the proper balance point. Lots of luck and I'm sure it can be done.

I think if the nacelles were put in the proper places, balancing wouldnt be much of an issue.

Large scale. This has been covered several times in the Twin and Multi Engine forum. I have done it three times myself. Only thing I would caution is that you do not compromise the spar system. It will be tempting when you try to fit a gas tank. On all of mine I added to the center section of the wing. A twin is inherently heavier, so I add some wing area. two fo my conversions were of a 60 sized airplane to a pair of 46's.
Chuck

LS88:

It's doable, the CG question isn't too difficult to solve, and as was suggested, don't cut the spars. There's an article on doing this in an old issue of Model Aviation (Dec 2008??), as well as a good discussion over in the Twins section:

http://www.rcuniverse.com/forum/m_9424157/tm.htm

Perhaps build a twin eingine kit to udnerstand the dynamics without having to think it out first. You could even use the wing and modify just the fuse of your current kit?

Ok thanks guys. What are some good twin engine kits out there?I haven't been able to find any.

Thanks