Platform pivot point

Question, I am in the process of making my full size platform and the question I have is where should the pivot point be located? should it be at the center of the platform or should it be where the seat position will be? In my case after I mount the Pit simulator components on the platform the seat will not be centered in the center of the platform. (see attachment) The weight of the components, monitor screens etc. should off set some of what you see.

Thank you Terry W.

throw everything on it, screens, controls, seat, yourself. Sit the frame on the floor on a broom handle and then you sit on it. Get someone to roll you back and forth till you find a balance point, and thats it.
If later you add or remove something, you need to re-do the balance point.
Under NO circumstances use springs to help balance, get it right first time.

I disagree with using springs. My pivot point is not exactly in the middle of the seat (more in the front), if I take a bump the seat will be lifted a little bit which gives me a better feeling. Of course you need strong motors or you use a spring helper (or both). In my real life I am driving a Renault Megane RS and analyzed very well the lifting effect of my car. Of course the rig will never be a 100% copy of your car but IMO in my case really near the mark.

I'm glad this thread was started. I'm at the point where I'm building my frame and the pivot point is a confusing one. Luckily I have a solution which will allow adjustment so it doesn't have to be uber precise first time round on the mock-up build.
The broom handle is a good idea though. That'll be a good way of getting it very close.

I have a seat mover and agree that the wanted pivot point is not ideal, but springs will load the motors up. It took 5 DC motors to get my sim close to my car. I drive a modified Subaru WRX STI. Unfortunately I don't get to the track as often as I would like which is why I built my sim.

Springs for balance , I think, were overdone on my original idea for using a spring to slightly load the wipers motors to stop them backlashing and wearing out too fast.
I think some people thought I used them for balance, I didnt.
everyones style of motion is different.
@Pit , if it helps you get a better feel with motion, then stick to it.
@SeatTime , yes getting a sim near a real car motion can be done as you have found out.
But as said, dont sort bad balance with springs, they will load the motors up and you rick loosing some finer detail in motion.
My sims are not 100% either, and if I move myself around in the seat, I can upset my balance slightly. Not enough to ruin motion though.

Barry, What is your solution?

Quite simple really. I'll try to explain as best I can.

I have a steel plate bolted to the seat frame and up the center of that steel plate I will have a row of around seven or eight 14.5mm holes. My universal joint which I took from a VW steering rack is welded to a base plate (which will be bolted to the frame) and the top bit is a thick steel tube (~4mm wall) with approx. 12.5mm center bore. I took a tap which was M14 x 1.5 and tapped the inside of the steel tube so I can just use an M14 bolt through the plate on the seat base and bolt it tight to the inside of the tube on the UJ.
If I think the balance is slightly off I can move the UJ forward or backwards 1 hole.

It's not dynamic and obviously would need a spanner to adjust but it'll be good enough to get the balance point for an average sized person.
The other option is to cut a slot in the plate so it would be much easier to slide back and forward. I'll update my thread as soon as I make a final decision on it. I'll try and get some pics up this week.

What is the best or preferred DOF (degrees of freedom) for a "Flight Simulator Platform" 10,20 30?
Terry W.

Hi Terry, I think you mean "angle of incidence" rather than Degree of Freedom (DoF). Think of DoF as the max number of directions of travel possible on a given system (roll, pitch, sway, surge, heave, and yaw).

To address your question; that depends on what feels good to you. A seat mover requires very little angle to get a good feel of movement, while a joyrider might take more. My full platform (monitors included) uses about 15degrees from level or 30 degrees on the full range of motion. For me 15 degrees feels like it is going to tip me out of the chair especially with an abrupt stop at the end and reverse.

Hello Historiker, Thank you for that correction. I am trying to keep this platform as low profile as possible. As of now I can get about 10 degrees and that is using a 8 inch distance between the base and the platform. Thanks again
Terry W.