Improved comfort for aerobatics

When I built my RV-8, I bought the Classic Aero Designs Aviator upholstery, so the original Vans front seat back was left over.
I figured it would be useful for flying with a parachute, just swap out the upholstered seat back for the bare Vans seat back.

My parachute is a Long-Softy, and it is slightly wedge-shaped. That is, it is thicker at the shoulders than at the lower back. I found that the combination of the fairly upright seat back plus the parachute shape gave a very upright seating position, with my face closer to the instrument panel than in normal position with the upholstered seat back.

I found that the very upright seating posture made me feel g's much more. Call me a whimp, but I'm a glider pilot, and I'm used to taking g's in a much more reclined posture.

So, what to do????

Well, I decided to modify the seat back to compensate for the parachute shape. Because of the natural curvature of your back at the shoulders, it is possible to set the backrest back more by putting a bend in it. The upper portion is more vertical, but you don't usually rest on that part of the seat back because of your shoulder shape. My modification consisted of cutting a wedge out of the side rail angles, bending them, then putting reinforcing plates on the sides to restore strength across the cut.

It took a couple of tries to get the bend right so that my back is more reclined, but the top edge of the seat back doesn't have too much contact pressure. I found the best bend angle for me is 20 degrees.

Here is a picture:


The result is a much more comfortable seating posture with the parachute on. My face is not so close to the panel, and I can tolerate more g's.

Hope folks find this useful

Very nice. I've only worn a chute once in my RV-4 for that very reason.

Very helpful!

I have just left the chutes in the hangar for this reason. I think I will give it a try. Oh yea it's time to get the chutes repacked also.

I also like your idea...

...of cutting the slots / holes in the lower seat back, for what I assume, is a better fit of the lap seat belt. How did this work for you? Any real reason that the seat belt did not fit around the entire lower seat back?

noelf said:

...of cutting the slots / holes in the lower seat back, for what I assume, is a better fit of the lap seat belt. How did this work for you? Any real reason that the seat belt did not fit around the entire lower seat back?

Click to expand...

That's stock for the RV-8 - mine is the same way. It does mean that when you want to take the seat back out, you have to mess with the seatbelt attachment bolts....

Paul's right

Yep, thats the stock seatback cut-out on the -8. Actually, I might have enlarged them slightly, I forget.
I have a safety pin - type clip in the seat belt bolt (instead of a cotter pin) on the side that has the buckle, so it is fast(er) to undo the seatbelt.
The other side threads through the seat cushion OK without undoing it.

But undoing the belt and threading it through the seat back and reattaching the seatbelt bolt is the most tedious part of the process.

Parachute bulk distribution

If flying with your parachute isn't as comfortable as you like, ask your rigger to distribute the bulk of the parachute differently inside of the container (pack) the next time you get them repacked. It's very easy for a rigger to do.

That's stock for the RV-8 - mine is the same way. It does mean that when you want to take the seat back out, you have to mess with the seatbelt attachment bolts....

Click to expand...

We have the cutouts, but with a little experimentation the (stock) seat belt buckles can get through the holes, leaving the bolts undisturbed

Andy

1:1 Scale said:

If flying with your parachute isn't as comfortable as you like, ask your rigger to distribute the bulk of the parachute differently inside of the container (pack) the next time you get them repacked. It's very easy for a rigger to do.

Click to expand...

Yes, this is good advise. At some point after this thread started, I figured out how to ask the rigger to pack the chute "diaper down" which puts more of the bulk at the bottom and reverses the wedge angle. This improved comfort in both my glider and in the RV-8.