1. Does a biplane have twice the lift of a comparable single wing plane (assuming th same wing length). For instance, a biplane with a modified clark y airfoil will have a certain wing area and related lift. If you removed one of the wings, would you loose half of the lift.
2. Secondly, if you built a single wing plane with the same type of wing with the same wing area as the biplane, would you have more lift?
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Reply:
Because of this interplane interference if you remove one wing the other will actually recover some lost lift so if you remove 1/2 the area you'll actually only remove about 1/3 the lift.

It's a rule of thumb that a biplane with twice the wing area of a monoplane only has about 1.5 times the EFFECTIVE area. But this IS only a rule of thumb. The actual percentage of relative efficiency depends on that interplane distance and the stagger effects and other stuff. But a biplane will never be as efficient at producing lift as the same area monoplane. And it will always produce more drag than the equivalent area monoplane even if you ignore the extra support structure drag.
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With this reply in mind, does that mean that you should calculate the wing loading for a biplane differently than for a single wing plane? Should you multiply the normal calculation by some factor (1.2 -1.5) to get an "effective" wing loading?

These questions are all related to my winter project - Beechcraft Staggerwing. I'm am building this model from Sid Morgan Plans and can't find anyone who has built and flown this model. The plane is a 64 inch wing span with 1200 square inches for both upper and lower wings (3 degrees positive incidence) 187 sq. in horizontal stab (2 degrees negative), will weigh about 12 - 15 lbs, and powered by an OS 1.2 four stroke (2.5 degrees down thrust). The air foil is a thin modified Clark-Y.

Since I can't find any real world reference for this kit/model, I am trying to "scientifically" determine how she will fly.

3. Most importantly, should I use the decalage stated above which for the full scale airplane? Should the decalage be modified for a model? The Royal kit Staggerwing has all surfaces at zero incidence.

This is a long message but very important to me.
Thanks,
Vic

You would compute the wing area the same as any other airplane but need to say that it is for a biplane or a particular model and the reader kicks in the appropriate feeling that it is more or less effective that a monoplane.

For a model that seems like a lot of decalage (define here as the angular difference between the wing and tail). Remember that the decalage between the wing and tail is what gives the airplane angle of attack stability. Something that is highly desireable in the kind of flying the full size stagger bipe would likely be doing. In the model size it would tend to behave like a trainer with respect to pitch. It would need to have a forward CG and 1g flight could be achieved at a fairly low flight speed, but, at high speeds that angular difference would cause a lot of pitch up.

For a model that might get boring after a while when just cruising around and you get the urge to do an outside loop then a smaller amount of decalage would seem to be in order. Having never seen either the Morgan or Royal kit fly it is difficult to judge. Has the Morgan design actually been built/tested? You might need to ask the designer.

As I found out, there are no known flying Sid Morgan Stagerwings (none that I can find). Sid Morgan is no longer with us and the folks at Vintage RC Planes (current vendors of the plans) have not turned up any flying models. I am sort of the ginny pig. I am trying to make this a successful adventure so that's why all the questions.
Thanks for the info,
Vic

Interesting. You might ask the question on the scale forum. I am sure I remember Byron Originals having a Staggerwing kit (large model) that flew quiet well. Someone there might be able to give you the information from that kit.

I personally like the feel of a pattern airplane and would tend to go toward the 0-0-0 setup just to get the better pattern feel. Now if I were at a scale contest with all knees knocking at the same time having a strongly self stabilizing airplane could be really useful.

With the large decalage you will get an airplane that when trimmed for a medium speed 1g level flight will give a pitch up with increases in speed and pitch down with decreases in speed. It will behave more like a trainer in that respect.

A lot will depend on your flying experience level. If you can confortably fly a average aerobatic airplane either setup will work for you. Although you will be able to detect the differences in rigging it will not be a big deal.

Ben,
Thanks a lot for the information. I have been flying for over ten years and others consider me an experienced pilot. I have several other scale monoplanes that have small decalage. I think I will keep some degree of positive incidence in the main wings and a slight negative incidence in the stab to maintain some self corrective stability. After all, this is not a pattern ship and will be fly only consrvative maneuvers.
Regards,
Vic

I forgot to say that there are lots of theories about which wing should stall first so that you need to adjust the angles to fit. In the big people carrying, so it's important, airplanes it is important to keep us alive and make up for a few human mistakes. Setting the angles to soften/prevent a stall is definitely important.

In the model world where it isn't life and death and the wing loadings are low and power is unlimited (mostly) then the stall characteristics of an airplane are not so critical and neither are the angular settings except for what I said before. It sure keeps life less interesting.