[simpits-tech] Simulating g

[Marv De Beque]

The g seat for the simulator at Dayton uses pneumatics to inflate the back
seat cushion.

Why not keep the straps static (that is, do not tighten or loosen them) and
inflate and deflate the seat cushion to provide a squeezing effect.  This
way you can set the straps before flight to a desired tension.

This would be much safer for the pilot and easier to control electrically
and electronically.

I would be worried of the possibility of strangulation if you attach straps
to a motor.

You can regulate the maximum air pressure with a regulator and a pop-off
valve.  10 to 15 psi max would be all you need.  You might be able to make a
bellows that could be mechanically operated by a motor or hunt around for a
electrically operated air pressure regulator (best choice) that you can
control by voltage.

If you have an eject handle I would strongly urge you to rig it so it
overrides the air pressure (a manual safety valve).

Instruct the student that if he is uncomfortable with the seat or anything
in the sim, yank the handle and it will stop the simulation.

That would be a good safety mechanism for your liability.

Any failure in the system would worst case cause a loud hissing (probably
muted by the cushion) and the seat back would deflate.

You can make a seat cushion from a toy raft used for pools.  You can resize
it by heat sealing it and cutting excess off.  You can make your own hot
wire heat sealer with some scrap parts and some wire hooked to a 12 volt
battery.  You just need to size the wire and control the current through it
to get the right temperature.

Marv
-- 


> From: Justin Messenger <jjmessenger@yahoo.com>
> Reply-To: simpits-tech@simpits.org
> Date: Tue, 8 Oct 2002 11:51:38 -0700 (PDT)
> To: Simpits-tech@simpits.org
> Subject: [simpits-tech] Simulating g
> 
> Here's the deal, I am going to have cadets use my sim
> and know using a g suit is not practical so I want to
> simply cause the shoulder harness to tighten when the
> stick is pulled aft. I need tips to use a motor to
> gradually increase the pull as the stick is pulled
> back past the center position, How do I get a 12V DC
> motor to slowly increase tension? For now it will
> simply be a mechanical interface from the stick to the
> motor. I have a rod running from my stick under the
> seat to the rear of the pit, so I can hook the motor
> to the rod for joystick input, Is there some kind of
> pot I can use to control the motor? What should it be
> rated?  Also, where would be a good motor for this
> use?
> 
> Justin
> 
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