Wing Tube Load
01-24-2022, 10:40 PM
#1
Thread Starter
Wing Tube Load
My apologies if this is not the correct forum for this question!
My Comp-Arf Extra is the older style--box wing tube and the wing spars are flat sticks that slide thru. The box is pretty solidly installed. What I would like to do is install the fuel and smoke tanks, AND two RX batteries on top of the box so everything is pretty much right on CG and the change in fuel and smoke level won't change flight characteristics as the fluids are expended. My concern is weight. By my calculations, I'd be looking at almost 6 pounds sitting on that box. If I changed batteries, at best I could get it down to 5 1/4 poiunds. Maybe not really a big deal until I start pulling G's. I figure that when the wings are attached, the combined strength of the spars plus the box, etc might be enough reinforcement, but as this is my first venture into this kind of thing, I figured I'd explore the experience of the experienced. Maybe I could beef it up, but that would be counterproductive, adding weight I'm trying to avoid.
So my basic question is, am I over thinking it, and should just go for it? Or are my concerns well founded and I should explore other options? Is 5 to 6 pounds too much?
My Comp-Arf Extra is the older style--box wing tube and the wing spars are flat sticks that slide thru. The box is pretty solidly installed. What I would like to do is install the fuel and smoke tanks, AND two RX batteries on top of the box so everything is pretty much right on CG and the change in fuel and smoke level won't change flight characteristics as the fluids are expended. My concern is weight. By my calculations, I'd be looking at almost 6 pounds sitting on that box. If I changed batteries, at best I could get it down to 5 1/4 poiunds. Maybe not really a big deal until I start pulling G's. I figure that when the wings are attached, the combined strength of the spars plus the box, etc might be enough reinforcement, but as this is my first venture into this kind of thing, I figured I'd explore the experience of the experienced. Maybe I could beef it up, but that would be counterproductive, adding weight I'm trying to avoid.
So my basic question is, am I over thinking it, and should just go for it? Or are my concerns well founded and I should explore other options? Is 5 to 6 pounds too much?
01-24-2022, 11:08 PM
#2
Thread Starter
Just had a thought. It really doesn't matter where I put what, because if my balance point is at or close to the wing tube, that's where the concentration of weight is going to be. The spars would be taking the brunt of the Gs, the box is just there as a guide. Most likely, if there is a problem, I will see telltale signs of it before catastrophic failure (I hope), and can make changes accordingly.
Thoughts?
Thoughts?
