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  #1  
Old 07-09-2010, 12:33 AM
scsmith scsmith is offline
 
Join Date: Jan 2008
Location: Ashland, OR
Posts: 2,573
Default 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
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Last edited by scsmith : 03-19-2019 at 11:45 AM.
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  #2  
Old 07-09-2010, 07:03 AM
Sid Lambert Sid Lambert is offline
 
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Location: North Atlanta
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Default

Very nice. I've only worn a chute once in my RV-4 for that very reason.
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  #3  
Old 07-09-2010, 11:18 AM
TOAD TOAD is offline
 
Join Date: Oct 2006
Location: Kent
Posts: 114
Default 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.
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  #4  
Old 07-09-2010, 11:21 AM
noelf noelf is offline
 
Join Date: Nov 2007
Location: Cary, N.C.
Posts: 1,216
Default 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?
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  #5  
Old 07-09-2010, 12:03 PM
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Ironflight Ironflight is offline
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Location: Dayton, NV
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Quote:
Originally Posted by noelf View Post
...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?
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....
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  #6  
Old 07-09-2010, 12:24 PM
scsmith scsmith is offline
 
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Location: Ashland, OR
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Default 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.
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Steve Smith
Aeronautical Engineer
RV-8 N825RV
IO-360 A1A
WW 200RV
"The Magic Carpet"
Hobbs 625
LS6-15/18W sailplane SOLD
bought my old LS6-A back!!
VAF donation Jan 2020
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  #7  
Old 07-10-2010, 07:47 AM
1:1 Scale 1:1 Scale is offline
 
Join Date: Aug 2007
Location: S21, Oregon
Posts: 161
Default 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.
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  #8  
Old 07-10-2010, 03:50 PM
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Andy Hill Andy Hill is offline
 
Join Date: Dec 2005
Posts: 976
Default

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

Andy
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  #9  
Old 03-18-2019, 11:16 PM
scsmith scsmith is offline
 
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Location: Ashland, OR
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Quote:
Originally Posted by 1:1 Scale View Post
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.
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.
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Steve Smith
Aeronautical Engineer
RV-8 N825RV
IO-360 A1A
WW 200RV
"The Magic Carpet"
Hobbs 625
LS6-15/18W sailplane SOLD
bought my old LS6-A back!!
VAF donation Jan 2020
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