A Thought on Fuel Consumption and C/G

[Dick Pacini]

Most agree that the fuel consumption alters the C/G and sensitivity of a C/L model.

Has anyone considered building a plane with a tubular fuel tank cross-ways in the wing right on the C/G?  Rather than affect the C/G, it would alter the effective tip weight.

It could be entirely in the outboard wing or pass through the fuselage with part of it in the inboard wing.

I don't know if suction would be an issue.  It might work better in a shorter nose plane.

Just an idea.

[Derek Barry]

I cannot feel any change in trim throughout the flight with IC. I didn't notice that there was no change when I flew electric either.

Derek

[Paul Smith]

The fuel weight is only about 10% of the total weight and it's only a little ahead of the CG.  On real palnes I've flown the acceptable CG range is something on the order of 15% to 35% of MAC, so a small CG shift is well within limits.  Furthermore you have the nose weight for inverted flight and more tail-heaviness for the later more complex stunts, so what littel CG shift there is works for you.

[Ted Fancher]

I cannot feel any change in trim throughout the flight with IC. I didn't notice that there was no change when I flew electric either.

Derek

Derek,

Fly the pattern backwards.

Ted

[RandySmith]

Derek,

Fly the pattern backwards.

Ted

There is a very slight change in the feel doing that, but in real world the change works in your favor when flying the pattern the correct way.

Randy

[Derek Barry]

Derek,

Fly the pattern backwards.

Ted

I will try that, but I have flown late in the pattern maneuvers before the wingover and early maneuvers after the clover to see If I could tell a difference. I can't.

Steve Fitton  told me that he left out his squares and could immediately tell when he did his triangles. I guess I have a muted sense of touch...

Derek

[Howard Rush]

Has anyone considered building a plane with a tubular fuel tank cross-ways in the wing right on the C/G?  Rather than affect the C/G, it would alter the effective tip weight.

Most combat planes with bladder tanks have tanks like that, usually in the right wing.  They go from too much tip weight to too little over the course of the fuel load.  The fuel load is about 20% of the model's weight, so it's a big effect.

[RandySmith]

Most combat planes with bladder tanks have tanks like that, usually in the right wing.  They go from too much tip weight to too little over the course of the fuel load.  The fuel load is about 20% of the model's weight, so it's a big effect.

Advantage pacifier over pen bladder !! ?? 

Randy

[Dave_Trible]

I always used a pacifier.  More pressure and held the fuel in one central spot.  On most airplanes there needed to be a small blister for it.  When I flew Guillotines the wing was thick enough no blister was needed for three ounces fuel.
The pen bladder ran down the wing and sure would change trim some- if the match ever went on for long.
Dave

[RandySmith]

 "Guillotines "



Guillotines.....  YUCK !!     


LOl Randy

[Dave_Trible]

Guillotines=Awesome!!

Dave

Added a pic of a Guillotine I keep around.  I have an old McCoy on it so maybe I can fly it without having to call 911.