Why two wings?

[nmroberto]

I guess this question is for the aeronautical engineers here.

I know that some of the factors involved in flying are..... lift, drag, and thrust.   

It would seem that having two or three wings would increase the drag, counteracting the lift advantage,  causing the air craft to be a lot slower. 

So why would they put more than one wing on a airplane?  Eindeckers among others only had one wing.

[IanB]

With the technology and aeronautical knowledge of the time lift was the key. Yes, it increased drag, but that wasn't fully understood. Neither was adverse yaw (drag created by the increased lift of the ailerons) - a factor which killed more trainee pilots than enemy action!

Ian

[dtomko]

I believe the structural rigidity of the box structure of two wings was also a factor.  Monoplanes required a lot of bracing and rigging; biplane wings could be lighter with each supporting the other by struts and less rigging.

Drew

[coyotemagic]

Besides, two wings look so much cooler than one.
Cheers,
Bud

[uncletony]

yep. it was really all about the box structure. The theoretical advantages of monoplanes were understood from early on, but the biplane was in practical terms easier to build to the required strength with the technology at hand. Towards the end of the war Fokker and Junkers made great leaps in cantilever designs and all that began to change... but ideas die hard.

[Thumbs up]

The RFC should have had more faith in the brilliant Bristol M1C.Even if it couldnt fire through its prop it would have bothered the Fokker scourge out of the skys.

[ermeio]

In the first days some monoplanes suffered structural failures, leading to the "monoplane ban" that lasted at least until 1916.

[ALBATROS1234]

its like drew and bo said, it was more economical and easier to make a strong biplane, they could handle more stresses in flight than the early monoplanes which as bo said they figured out early on a monoplane made more sense but the engineering was in its infancy so all of those things we know they were just starting to scratch their heads about. remember ww1 broke out 11 years after the wright brothershad the first hop across kitty hawk. the french were really the european flight masters early on with santos dumont,voisin and bleriot. this is what makes our hobby interesting though.

[vincentm]

When you flew an Albatros at this time, you were happy to have two wings in case one of them would go and live it's own life...

[Des]

Just look at the Cessna/Beechcraft Staggerwing, a biplane with absolutely beautiful lines, even though it had two wings it was way ahead of its time, and still looks really good today.

Des.

[nmroberto]

Just look at the Cessna Staggerwing, a biplane with absolutely beautiful lines, even though it had two wings it was way ahead of its time, and still looks really good today.

Des.

You are right, it was beautiful..  Do you know if anyone makes a decent kit of it? 

[Des]

Roden make several kits of the Beechcraft Staggerwing in 1:48 scale, they have the Beechcraft UC-43, the GB-2 and the D17S, I have not built the kit but from what I have heard it is not too bad.

http://rodenkits.com/catalogue/1-48/page-4

Des.

[David 63]

Besides all of the above, you have to consider that the engines of the day didn't have the power output of later (say 1920's to the end of ww2) engines and they were heavier too. two wings provided more lift to overcome the power to weight ratio.
Dave

[vincentm]

I believe the structural rigidity of the box structure of two wings was also a factor.

Sure, that makes sense, and you can even experience it on a kit: on a biplane, when only the lower wings are attached to the fuselage, they are pretty fragile. When the upperwing and masts are installed, the whole structure is much more rigid, and it gets even better when the rigging is on.

Monoplanes required a lot of bracing and rigging; biplane wings could be lighter with each supporting the other by struts and less rigging.

In the end, you have more lift for less drag with a biplane. Of course, things changed when engineers were able to build strong enough cantilever wings. In the thirties, there were still a debate about what was more important: maneuverability of the biplane formula, or speed of the cantilever monoplane architecture. In the end, the I-16 and Bf109 put an end to this debate during the Spanish Civil War.