Uncle Sam Review     

by Bill Kuhl http://www.scienceguy.org

Most model airplane enthusiasts have the urge at some time to build or own a model biplane. No doubt nostalgia has something to do with it but then the idea of building yet another wing and attaching it to the airplane can put a damper on the enthusiasm. The “Uncle Sam” rubber powered free flight airplane is not much more work to build than similar single wing airplanes. Uncle Sam has no dihedral at all yet flies in a stable manner because of tip plates that span between the wings and there is one in the center also.
Bill Hannan, a famous model airplane author designed both Uncle Sam and also “The Stringless Wonder”, a rubber powered free flight model plane that looked like a kite. Both planes fly very well even if their appearance is somewhat unusual. The kit has been produced by Sig Manufacturing for many years; I had built another one several years ago and was impressed how well it flew. On the first plane and the current plane I used tissue for covering instead of the heavier plan material included in the kit.

Construction is very straightforward in that pretty much everything is a rectangle. Framework is 1/16” square balsa that is smaller than used on some beginner airplanes. The balsa was not a real light density which makes it somewhat easier to handle. There is not much glue contact area with 1/16” square sticks so it is important to get solid glue joints. I use Duco brand glue which can be found in hardware stores and “double-glue” each joint. The process for double-gluing is to put glue on the joints and let it soak in for a couple of minutes; then use a second application of glue and then stick the parts together. This should make for glue joints that are considerably stronger.

To save a little more weight I cut a taper in the fuselage about 4 inches from the rear to the end. I always try to save weight in the tail-end of model planes because it takes so much weight in the nose to counter-balance a plane that is tail heavy. The wing of the Uncle Sam uses a piece of tape around the sides of a balsa bracket and around the bottom of the fuselage. For a small plane this appears to hold and allows adjustment.

So far I have only done some test flights on hand winds but the plane appeared to be in trim and climbed out on minimum power. I will try to get some flight pictures to add to this article soon.

Links:

About Bill Hannan
Sig Product Description Uncle Sam