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RUBBER BAND POWERED AIRPLANE HELP REQUIRED.

I AM MAKING A RUBBER BAND POWERED BI PLANE. I HAVE COMPLETED THE WINGS AND AM GOING TO ADD THE TAIL SECTION. THE PROBLEM IS THAT MY MODEL SO FAR IS NOT AERODYNAMIC AND JUST TUMBLES THROUGH THE SKY. IF SOMEONE COULD GIVE ME TIPS ON HOW TO MAKE IT MORE AERODYNAMIC IT WOULD BE OF GREAT HELP. A;SO HOW AM I TO ATTACH THE ENGINE. 
PS THIS IS MY FIRST MODEL AND I AM PLANNING TO MAKE AN INSTRUCTABLE.

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rickharris6 years ago
Your plane needs to be aerodynamically balanced.

Build FULLY then ensure it balances left and right and the point of balance front to back should be about 1/3 of the distance back from the front edge of the wing. this is with ALL the plane assembled prop rubber and all.

This set up should glide Ok when pushed off in a slightly downward direction although it may need a bit of speed depending on it's weight/wing area.

If this works OK then you can put a few turns on the rubber motor and see what happens. You may need to block up the rear edge of the wind under power to keep the nose down.
An airplane needs a few things in place before it will fly.

It's good to try a proven design first so you can see what does work. A great proven design is the Squirrel rubber band plane. Make your own designs after that. Unless of course you are determined to come up with something new and have a lot of time to do this.

Pitch stability is one thing your plane needs. For that you need a wing and a horizontal stabilizer (back wing if you are making a traditional airplane). The wing should have a positive angle of attack compared to the back wing. The balance of the airplane should be somewhere on the wing.

Roll stability is another thing it needs. There are a few things that can work for this. Dihedral which is having he wings sloped up this works in conjunction with a fin at the back of the plane to create yaw roll coupling which results in roll stability.. Back sweep can also contribute to roll stability. Winglets can do this as well (like in the Squirrel design).

You also need yaw stability. A rear fin works for this.

This is all for a traditional tractor type airplane. It's different if it is a canard style or a flying wing style. Flying wings use reflex to get pitch stability and are much more sensitive to adjustment. I don't know as much about canards.
yapoyo6 years ago
This is a simple way to make a paper plane. take a piece of paper and make a regular paper plane. then cut a notch and launch it alike with a slingshot.
First of all, you must clarify how it tumbles. There are several dimensions in which a plane can "tumble". Many of which require entirely different cures.

If you need roll stability, add dihedral deflection where necessary. If you need to prevent yawing motions, add and increase the size of the vertical stabilizer and/or the wingtips.

Generally, model biplanes are easier to make if they use annular wings like my YD142-1 prototype, seen below.
YD142-1.JPG
luftwaffe29 (author)  OrigamiAirEnforcer6 years ago
UM THE PICTURE YOU HAVE POSTED IS OF A PLANE THAT IS STREAMLINED AND LOOKS MORE LIKE A JET.
THE BIPLANE I CREATED IS MORE STUBBY AND LOOKS LIKE A BIPLANE AND IS MADE OF CARD. MAYBE THAT IS THE REASON IT DOES NOT FLY. PERHAPS ILL SEND YOU A PICTURE. UR ANSWER IS REALLY GOOD. THANX FOR BOTHERING.

COMING TO THE TUMBLING MY PLANE SPINS FORWARD AND GLIDES VERY SLIGHTLY JUST BEFORE PLOUGHING INTO THE GROUND.
As rickharris said, you must balance the airplane. One of my planes, the Scout (https://www.instructables.com/id/How-To-Make-The-Scout-Paper-Airplane/), is completely balanced in the every dimension, because each side forward and back, right and left, has weight equal to its opposite. It had been designed from the beginning like this for simplicity. You must also balance lift output, or a point of greater lift will "overpower" its opposite and turn the airplane. This applies for all lifting surfaces.

Aerodynamically, I really never design planes that aren't "clean". I generally have as much of the plane made sleek as possible. When drag is unnecessary or not desired, it should be fixed. That should increase range and potential speed. 

As for stability, if you are describing correctly "spins", then your airplane seems to be stalling very quickly. If your plane is to have or has an engine, then it is likely pulling into a flat spin. To cure for this problem, increase the size of the vertical stabilizer, and perhaps even trim the plane if you need to. 
luftwaffe29 (author)  OrigamiAirEnforcer6 years ago
COULD U SEND ME AN INSTRUCTABLE ON HOW U MADE UR BIPLANE
As of right now, I have not made one. I do plan to in the future though. Right now, I have very similar mono-wing planes which fly faster and further. They can also be seen below:

All of these planes are very comparable to the prototype above, and all have instructables already posted. I have found them very good testbeds for many configuration experiments.
Instructables 32 024.jpgInstructables 34 012.jpgInstructables 30 020.jpgInstructables 38 017.jpg130_3516.JPG
iceng6 years ago
There is no tail by your own words!
Are you an aerodynamics genius or do you have plans ?
Is the band the engine ?
You are vague on lots of points.

A