Some "theoratical" people came to me and challenged to build an aircraft measuring a maximum of 2 ft by 4 ft and 1 ft high, capable of carrying a 6 lb payload as well. I say this is a waste of time and money and I am out of the challenge but they say it is a small deal and are trying to organize a contest for it.
Why do you think it's a waste of money? It doesn't seem like you know very much about the contest at all. What you are speaking of is the [link=http://www.ae.uiuc.edu/aiaadbf/]AIAA Cessna/ONR Design/Build/Fly Contest[/link]. It is an annual event and teams from universities around the world participate. This year will be its 10th year running.
This year's contest is the
fourth year requiring that all contest aircraft fit inside a 4' x 2' x 1' box. The aircraft can certainly be larger than those dimensions -- it simply must disassemble to fit in the box.
Each year the competition specifies new rules and missions. The mission you are asking about -- carrying two 3 lb payloads at the wingtips, was one of the missions from
last year. [link=http://www.terrabreak.org/hangar/ok-state/images/ok-state.2005_1.photo2.med.jpg]There[/link] [link=http://www.terrabreak.org/hangar/wsu/images/wsu.2005.photo3.med.jpg]were[/link] [link=http://www.terrabreak.org/hangar/ucsd/images/ucsd.2005.photo3.med.jpg]several[/link] [link=http://www.terrabreak.org/hangar/usu/images/usu.2005.photo5.med.jpg]teams[/link] [link=http://www.terrabreak.org/hangar/usc/images/usc.2005.photo5.med.jpg]competing[/link] which had no problems creating an aircraft to these specifications.
I just said its very stupid .... do you agree or not ?
Yes, it is very stupid to make judgements about things you don't know anything about.
Oops, you meant is the
contest stupid. No, it's not. The DBF competition is a valuable experience for all teams involved. It is a great way for engineering students to take a design process from start to finish.
What engine would you use ?
Where do you place the engine and stab ? What do you think is the chord length of the bipe ?
What prop would use ? Can you fit both the wings with landing gear in 1ft High box ?
Previously the contest had fairly strict rules on brushed electric motors from Graupner or Astroflight. Recently they have opened up motor selection to include any commercial brush or brushless electric motor.
Place the engine or engines wherever you determine is the best place for your design. . .at the nose, pusher at the rear, dual engines on the wings, whatever floats your boat!
What prop? Depends on what kind of ground clearance you have, how quickly different props will drain your batteries, if you need something to cut through strong winds, or something low power. . .there is no one answer! These are the kinds of questions that are supposed to be analyzed by the students participating in the competition.
Yes, you can fit the wings and landing gear in a 1 ft high box. You may design for retractable gear, or short gear, or gear that attaches once removed from the box. . .
Regarding the wings, most teams design wings which detach from the fuselage, however last year [link=http://www.terrabreak.org/hangar/ms-state/images/ms-state.2005.photo1.med.jpg]MS State[/link] designed a tri-plane with three 4' wings.
These sorts of questions you're asking are not insurmountable obstacles -- they are simply problems that require intelligent engineering to achieve a workable solution. That's what the contest is all about, and that's what most engineering is all about.