I'm thinking about bashing a 4*120 into a biplane. I have a complete wing kit and a set of plans. It will be easy to trace the wing parts and cut them out on a scroll saw. I can scrath the fuse off my old plans. I want to widen the fuse, because the stock 4*120 fuse is very narrow. Hard to get my fat hands inside. Thats a simple mater of increasing the width of the fuse formers.

I will mount the top wing slightly forward of the bottom wing. Both wings will be shortened from 81" to around 72" so that I can get them in my truck.

I am pretty sure that I'll need to change the length of the fuselage. I think it should be extended out a bit to help with stability. I don't want an overly pitchy plane. In stock form, the fuselage is about 65" long. I was planning to lengthen it out to about 71". Again, thats strictly based on my limitations for transport. I'd like it longer, but it still needs to fit in the truck.

There used to be some pictures floating around that showed basic ratios.
I.E. Wingspan:fuselage length --- Cord:wingspan --- Horizontal surface area:wing area

Does anyone know where I can find these ratios? Needs to be bipe specific.

Any other help on the design would be great.

You don't need to change the fuselage length at all. But I would plan on making the tail surfaces larger to make up for the increase in wing area. The tail surface areas should be increased by about 20% each.

If you make it much wider without making it taller it'll look odd if you do it too much. A small amount would be OK though.

And don't forget that the upper wing struts will require some hard points and spread out structure added to the fuselage to properly support the upper wing loads.

Sounds like a fun project. Be sure to post up a build thread in the Scratch Build forum since this won't be much of a kit build anymore.

Definitely going to put some structure in the top of the front hatch area to accommodate the inner struts. I'll have to modify the center section of the upper wing too. No big deal.

I kinda figured I'd need to increase the size of the tail surfaces. I have been trying to think of a way to change the rear of the fuse so that I can use removable airfoiled stabs. I won't do it unless I can figure out how to mount a couple low profile servos in the stabs. I've always hated those planes that have removable stabs, but the servos are still in the fuse. You have to disconnect the linkages every time you want to take the stabs off. I think it's doable. I'll just have to find an airfoil. My friend thumbed a 25% Edge 540 recently and I know he still has the tail section. I might dissect the stabs and rudder to trace some of those ribs. But my brain is struggling with how to modify the fuse in the back to accept a wing tube. Gonna need to add some wood.

You mentioned making the fuse taller. I think the turtledeck will need to be raised to accommodate the removable stabs anyway. That might work out just fine. I need to draw it on paper.

I can't build anything stock. [sm=tongue_smile.gif] Just can't seam to sit down and build a kit per the plans. I just love to make small modifications here and there. This particular kit bash would be the most mods that I've ever done to one kit.

The other thought is to have the halves slip on and at the same time the elevator engages a driving element of some sort. That way you don't even need to worry about connecting and disconnecting the servo lead all the time. There's lots of options for such a setup that would just depend on what the fuselage looks like and wnat methods you're comfortable in working with. One of them would be to just go with a full flying stabilator like the glider guys do. And there's lots of full sized aircraft that use this method as well. It's actually a total natural setup for slip on stabilizers. Make the carry through rod the pivot as well and drive the whole stab.

If you go that way or not a good airfoil for the stab is the Selig 8020. It's a good symetrical airfoil that was designed for low drag and to resist stalling when used as a full flying stabilizer airfoil. It's actually a pretty good airfoil for aerobatic wings as well as a result.

Do you have a copy of the plans for the ace 4.120 biplane that I can buy from you. My hubby bought an open kit from a pawn shop and there are no plans or parts list in the box. We have searched everywhere to try to locate some plans for the plane. Thanks.
auntlucy, [email protected]