Good dialog, and useful.
The old straight arm position had a lot to do with unsupported seating.
You could hang onto the wheel to keep your body somewhat in position. I
find the most important support for this patched together body I have is
in the shoulders, so my seats are super ugly expanding foam and ductape.
Once I'm belted in my upper body is in a socket with my arms and shoulders
free.
This winter I'm going to move the pedal box as far away as I can, and lay
the seat down a little. I'll wind up closer to the wheel in the gut, about
the same at the shoulders, and I should be able to increase the side
support a bit. My aim is to get down out of the air a bit and get my back
relaxed a little. I tend to get backaches after long drives.
-----Original Message-----
From: Rocky Entriken [mailto:rocky@tri.net]
Sent: Wednesday, October 22, 2003 12:33 AM
To: Group44TR7@aol.com
Cc: fot@autox.team.net
Subject: Re: Recommended Seat Position
Well, the first reaction I'd have is that aircraft experience does not
apply here. I have a bit of Av background also -- my military time was in
Navy Aviation (no I did not fly, but I was around those who did), and my
baby brother is an F1 air racer.
Our cars don't pull the g-loads a jet pilot encounters. In fact, that jet
pilot's g-loads tend to be vertical as he is tilted almost 90 degrees over
when doing a fast, tight, high-load turn. It's also why they wear G-suits,
to prevent the blood from rushing out of the brain and into their legs and
making them black out. Not a problem we encounter much. Our G-loads are
lateral, and the Kirkey [not Kirby] is designed exactly for that.
Said pilot is also generally flying with an arm position that has his
elbows by his ribcage, a very relaxed position. A race car's steering
wheel tends to be roughly chest-high while the jet pilot's joystick is
down around his navel.
So we tend to sit reaching out to the wheel. My old seat had me reaching
so far my arms were almost straight out. Virtually all leverage of turning
the steering wheel was in the shoulder muscles (I was younger then too!).
Now my upper and lower arms are almost 90 degrees at the elbow, and I have
better leverage turning the wheel using arm muscles.
Look at an in-car at a NASCAR race. They sit so close they often have
their elbow ON the wheel, giving them even more leverage as they turn the
car. These are guys who are in their car 3-4 hours at a time, not a half
hour like we do, so they have really studied how to last that long while
conserving energy.
That seating position is a major aspect of that, and those guys sit
straight up. Open-wheel racers (F1, CART IRL) tend to be more
straight-arm, but their wheel takes a one-inch turn to get around most
corners.
The G-loads our Spitfires generate are closer to Piper Cub than F18. So
that is of negligible concern to us. Comfort and leverage are much more
important.
That said, the real factors determining whether your seat should be
straight up or tilted back has to do with two aspects -- how far your
hands reach to the wheel (you want an arms-bent position) and how far your
legs reach to the pedals (you want pedal to the metal - gas & clutch -- at
full extension but without going tippytoe to do it). For me to maintain
the arm position I now want, to have the seat tilted would mean moving it
forward and that would cause me to sit bowlegged (which I already do
slightly anyway). In my case, it is as if the back of the seat were
located in the same place (old seat vs.
new) but I rotated the upper portion forward. Thus my legs/lower body are
no closer but my arms/upper body are.
When we installed my Kirkey, first thing we did was just put it on the
flor of the car, loose, and I sat in it at various positions until I
decided what was comfortable and best leverage. Then we marked where it
was and drilled the bolt holes.
--Rocky
----- Original Message -----
From: Group44TR7@aol.com
To: rocky@tri.net
Cc: fot@autox.team.net
Sent: Tuesday, October 21, 2003 2:32 PM
Subject: Recommended Seat Position
Rocky
I found your comment about the physical position of the seat
(level on the floor) to be very interesting. It was very recently
recommended to me that I have a new seat inclined slightly backward. The
person giving the recommendation, who has aircraft experience, says that
combat pilots seats are inclined backward because it is a better position
for a person body under the stress of high speed turns.
Does the Kirby, by design, already has some inclination in it
when position on the floor? Or should I be seeking some second opinions
about the positioning of the seat.
CP
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