why were the first airplanes bi-planes?

Answer 1

The first attempts were mono-wing. The first successful plane was bi-plane using the top wing as the control surface. The mono wing became popular as speed became the requirement.

The Bi-wing configuration is being considered again for re-entry type vehicles. An interesting note is the feathered dinosaur 'Microraptor' had four feathered appendages and is considered to have flown or glided in a bi-wing configuration.

An interesting site is, http://en.wikipedia.org/wiki/Biplane. It has many good links as well, and
http://en.wikipedia.org/wiki/Biplane#The_biplane_in_avian_evolution.

Note: To get a full understanding of the Wright brothers inventions including "Wing Warping" as a means of flight control see, http://en.wikipedia.org/wiki/Wright_brothers

They also designed their own engine which used an aluminum block to maintain low weight.

The Catapult was used on the Flyer II in July of 04.

Another article from the Scientific American can be found at, http://www.sciam.com/print_version.cfm?articleID=000E2A9A-2E05-1FA8-AE0583414B7F0000

Answer 2

for a few reasons actually;

1: structure. in order to get a lightweight structure that was strong enough to handle the flight regime, you needed the second wing. this gave you the ability to keep the weight down, and brace everything with wires in tension.

2: weight. the lighter you make something the less power you need to use to propel it.

3: power. the early engines didnt make a lot of power. in fact the wright brothers had to use a catapult on the first rendition of the wright flyer to get it into the air.

4: lift. the early wing designs didnt generate enough lift to overcome gravity, so a second wing was added.

5: drag. the wing design that would have met the above requirements at the time would have created too much drag to allow for performance at the low speeds of the time.

6: stability. at the time bi-planes were more stable than mono-plane were in the early years.

Answer 3

Primarily because they needed a large wing area to compensate for the low engine power, but couldn't build a large mono wing with a light enough structure.

The biplane design allows an open truss design that has good strength to weight as someone mentioned.

It also allowed for less rolling inertia for the same wing area (something that makes the Pitts a really good aerobatic plane).

However, the biplane design is inefficient. The struts and braces create drag, there is more induced drag (since there are four wingtip vortices) and the wings interfere with each other's airflow.

Answer 4

At the time that the first planes were built enginereering was not far enough along to build a wing of adequate strength. Using two wings allowed for a modified truss construction so that the load was shared between them. The first monoplanes had a little tower on top of the fuselage so that wire rigging could be used to brace the wing on the top side.

Answer 5

some were gliders,but
engines were heavy and fabrication material
limited structure.
design and technic were/are quite impressive.
A great thing to study at a vintage museum.
A local crop-duster here in ONTARIO uses a Bi-Plane
powered by a radial engine. The Engineer told me,
water need to be in the tanks for takeoff to help counteract
the torque of the engine and propeller vs the airframe.
Basically, it would flip over without the ballast.

Answer 6

Early power plants didn't have a lot of horsepower so they needed all the extra wing surface to get the needed lift. Also because of building materials available at the time they needed the structural support that the double wing design offers.

Answer 7

Bi and tri. With the weaker but much heavier engines in the early days, more lift was needed. The extra wind surfaces did the job.

Answer 8

They went both ways. It is a personal choice.