[Land-speed] cockpit design and layout OT

Ed Weldon 23.weldon at comcast.net
Tue Aug 28 17:54:47 MDT 2007


Greg-- 
There are no "right" dimensions.  Every car situation is different, every
driver is different.  In general give yourself as much space to start as you
can afford.  You can always adjust the seat inward.  Make sure you have the
rule book for whatever the applicable racing organization in front of you.
Much of the layout will depend on safety considerations like protecting
various parts of your bod.  This gets a lot of "ink" in LSR forums.
Remember you have to be able to see and/or reach all the controls and
instruments.  Oh yeah, and the course ahead.

If you're any good at drawing to scale get yourself a positionable human
figure drawing template.  Google search "Alvin TD1735BG Human Figure" for
sources of one example.  Cost is less than $10.00.  Then you can draw the
rough dimensions of the car components like seat, steering wheel and pedals
in side view profile in a scale drawing.  These figure templates range
around 1/8 or 1/10 scale an usually represent the statistical average human
figure dimensions.

OK, you say your driver in not that average size?  Go find a copier (Kinkos)
to scale the pieces up or down.  Cut them out, paste them to pieces of this
cardboard (like cereal boxes) put them together with pins at the joints and
set them down on the drawing.
While at kinkos make some copies of your scale drawings of car components
and glue them to cardboard shapes.  That way you can move them around also
on the drawing of the car frame.

Now, you say you can't draw worth a darn.  Do it full size on the garage
floor or out on the patio.  This is how wooden boats get built using a small
scale drawing or sometimes just a table of offsets.  They call it "lofting"
in that world.
Use whatever cheap materials are available like large corrugated appliance
box panels, old plywood to rough out a seat, etc.  I even used 6" radius
1-3/4 exhaust u-bends and 1-1/2" electrical conduit to mock up a roll cage.
You can rough out a pretty sturdy cockpit and firewall shape from 3/4"
electrical conduit.   Get all possible drivers to test fit this layout.

Here's a tip:  Look for an old out of date belt and shoulder harness setup
to use when your construction gets far enough along to test the fit of the
driver.  That way you can wait until the last month or so before the first
tech inspection to buy a fresh belt set.

What I would not do is try to design it entirely on paper or a computer CAD
system and then just go start cutting metal or building molds.  It takes
years of experience for a designer to be able to layout a driving position
in a vehicle properly in addition to the CAD/drawing skills and exceptional
spatial visualization talents needed to solve the myriad of 3 dimensional
fit problems.  In all probability you don't have it.
Ed Weldon,  Los Gatos, CA

----- Original Message ----- 
From: "Greg Meyers" <advo at comcast.net>
To: <land-speed at autox.team.net>
Sent: Tuesday, August 28, 2007 2:57 PM
Subject: [Land-speed] cockpit design and layout OT


> While we're on the general topic, does anyone have a good source for
general
> guidelines on cockpit design? I mean like measurements from seat to
> firewall, seat back angles, distance from shoulder to steering wheel.....
> I'm designing a vehicle from the ground up which will be used for driving
> twisty roads. It will use the turbocharged flathead six XO motor we raced
on
> the salt last year (land speed content).
> Thanks
> Greg


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