Effect of adding wing tip tanks

[tipperary]

I think adding wing tip tanks adds a certain presence to some planes. I am thinking of adding some to my Multiplex Space Scooter carving them from Balsa. I will have to cut off a short piece of the ailerons to fit them.What might be the effect on wing airflow etc., ?

[Sparky Paul]

The roll rate may improve.

[vintage1]

You may go a little faster - wing tip gatse to break up spanwise flow can modify tip vortices...but on a dfoamie of this quality, I hardly think you will measure the difference.

[danstrider]

I wanted to do some mid-span tanks beneath the wing on a trainer once. 1.5lb 15" from the fuselage centerline of a 12lb senior telemaster. I can say from experience that the model seriously did not want to roll. I guesstimate that I tripled the wing inertia. Even with full-span ailerons on high-rate, I had to supplement the ailerons with rudder. I have the equations for rolling inertia somewhere, but defintely try to keep 'em light if you want it to roll like normal. Inertial coupling can be not as much fun.

Dan

[jkettu]

What everybody said above. On a practical note, you might want to attach the tanks in such a way that the attachment fails before anything else breaks.

[HELModels]

I would think that if you were to imagine a CFD simulation program, there would be a huge cloud coming off the tanks. It might also look like ice accumulation on various parts of a moving ship, long jagged trails suggesting motion. I'd be more concerned with stall behavior, with no contribution to stability.

You might want to consider using formers of foam and hollow out the innards and then stack them up for shape.

Do it and have fun.