Square Blimp

[Nader]

I know this is going to be kinda crazy but I'm trying to think outside the box.

Is there a good way to build a square blimp without taking up all the lift capabilities with a frame? I want to build an 8' X 3' X 4' blimp out of mylar, but I'm having difficulty with the shape. I have a 3' high constraint so to maximize the volume would like to make it square. Are there any other considerations of flying a square blimp indoors? Aerodynamics? My initial thought is it probably won't matter since there aren't any weather calamities indoors.

I am trying to carry a 4-5 pound payload with this blimp. With a blimp this size how large of motors do I need?

Appreciate any help you could provide!

- Nader

[Majortomski]

Nader, first you're not crazy or oustide the box, you just want an unususaly shaped blimp. First the good news. I had long heard that as a rule of thumb 27 cuft of helium lifts one pound. On another site, it indicates that only 16 cu ft will lift this pound. So your blimp can theoreticlally lift 6 pounds. Bad news is squares are hard to do. you are asking for a 96 cuft bag. A cylinder 9 feet long and 3.4 feet in diameter would give you the same volume.

I use three speed 400's with direct drive 6x3 wood props on my 13 foot blimps. I suggest geared GWS motors and props would work well.

Tom

[Nader]

Thats great info. Many thanks.

About your motor configuration... Do you use 2 motors on each side of your gondola and another motor for lift? Also do you protect your props in anyway? I need to be very very accurate in manuvering my blimp. Is this the best motor configuration for accuracy?

Thanks for all the help.

[Majortomski]

Sorry for the delay in getting back. I forget to check blimps daily.

IN the blimp in the picture, a motor in the tail runs forward and backward off of a car speed controller to provide yaw steering. The main fans sit pointing between 45 and 60 degrees up and pitch up and down to climb, decend and back up. Combinations of power and pitch angle controll speed or altitude. I tried having the main fans have differential thrust for steering, works well so long as you maintain forward flight. IN a hover with the props pointing straigt up you have no steering, thus the tail fan.

HTH
tom

[Iepurila]

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