Great Lakes Bipe CG?
 

Would like to know where to balance the 47" great lakes bipe. I understand that this plane is difficult to fly! Would still like to try to fly the plane if I can balance it. Thanks if you can help.

RE: Great Lakes Bipe CG?
 

Balance point.

AA biplane requires the top and bottom wing be included in a total chord measurement. With the swept top wing, of the Great lakes for an example, I would measure from a point half way out board from the wing root. Set up the craft in a level condition, that is with the tail up until all is as level as possible. Then using any 90° instrument, measure the distance projected to the table, from the leading edge of the top wing to the trailing edge of the lower wing. This distance is the total chord.

If you want a very stable craft, then balance the craft back from the leading edge 25% of the chord. The aerodynamic center of pressure is normally some where behind this center of gravity point. This is why we have to trim in up elevator (produces a downward force on the empenage) to maintain level unaccelerated flight.

On landing a craft in this configuration, you will need to carry more than normal speed in order to maintain elevator authority unless you have a lot of elevator surface area.

If you want a more agile rapid responding craft, move the CG back to no more than 35% aft of the leading edge of the total chord.

Hopefully this information will be helpful.

Best regards,
THC

RE: Great Lakes Bipe CG?
 

I had that plane. I think it ballances directly over the leading edge of bottom wing. Hard plane to land. After I put it back together for the second time I decided to have fun with it. High speed touch and goes! One time I touched down at full throttle and it didnt go any more.

that plane is so cute you simply wont accept that it flies like crap. Take my advice, find a kid on your street and give it to him to hang in his bed room.

RE: Great Lakes Bipe CG?
 

Gentlemen,

If any of you have these Model Tech Great Lakes Biplanes that are intact, and not damaged, I will be glad to take them off your hands and will pay the shipping. Send several pics, all sides, that means 4 views taken close enough for examination. I am particularly interested in units that have not been finished or covered.

If I might ask a question, what power plants did you people mount on the craft.

Best regards,
THC