Biplane Wing Spread Question.

[Butch777]

I understand that the distance between the upper and lower wing should be at least the distance of the wing cord, inc the aileron.

I'm building a EPP parkflyer, with about a 26-28" wingspan, about 6-8ozs.
I'l probably try a symmetrical airfoil at first, then maybe a semi-sym.

I'd like to get the widest wing cord possible, for the most wing area in the 26-28" span. Because of the slower flying speeds, ailerons will be about 1/3 of the span.

Do you think that at the lower speeds, with the large ailerons not needing to deflect so much to turn, I'd still need the wing spread to be at least a cords worth??
Also, if I stagger the wings more, would that help?
And what happens if I stager the wings alot??
Thanks for any help, Butch

[eflightray]

If I remember right, for model aircraft, a smaller gap between the two wing just increases drag slightly. If you want slow flying, it shouldn't make much difference.

If you do a scale model, then the struts and bracing wires, will cause more drag than the reduced gap.

I've often thought a sports biplane with a narrow gap, one wing on the bottom of the fuselage, the other straight on the top, with no struts, and say half a chord stagger could look quite 'mean'. Some of the Curtis seaplane racing biplanes had what looks like a smaller gap.

[eflightray]

Just remembered the old Stagger Bee, the biplane version of the Lazy Bee, (can't get a much lower aspect ratio wing than those).

Hopefully here's a picture - Stagger Bee (http://www.rcgroups.com/forums/attachment.php?attachmentid=187080)

I was thinking something similar but with more of a 'sports open cockpit' body.

[HerkS]

For a park flyer you should be able to build pretty much what you want it to look like.
Gap and stagger are mostly for efficiency in terms of lift and drag. Neither of those is very important for a park flyer. In terms of gap - the larger it is the less the airflow over one wing affects the other in terms of both lift and drag. The upper wing was usually put ahead of the lower wing and sometime has a bit more incidence than the lower wing. That was done so that the upper forward wing would stall first for safety reasons.
There is a lot of info on the internet. Do a search on "biplane aerodynamics" if you really want to explore the subject.

[Butch777]

Thanks Guys,
I'm building a Ultimate style at first, then maybe more of a custom.
I've always been interested in a bipe with a lot of stagger, reasoning it would increase the over all wing cord and maybe maybe add alot of longitudinal stability. Butch

[HerkS]

Keep in mind that if you want this to be an acrobatic model, whatever makes sense when the model is upright, has the opposite effect when inverted.