best angle for rear mount motors

Hello all, I am looking at mounting the motors on my sim at the back and connecting to the shoulders of the seat.
I believe 15 deg of angle is about what is needed, however, do I calculate the angle at high lever point, middle lever point, or low lever point.
Example, I will need about an 80mm long lever.
Lever at centre will be 19.7 deg, lever at high or low point will be 15deg. Thats with the lever swinging out.

Alternatively, I can mount the motors so the lever swings inwards, making the centre angle at 15 deg, that would make lower point about 11.7 and upper at 11.7 deg, I think.
Should I be reducing the angle at centre point or leaving it as is?
What would be the better option here.
I am using motors and not actuators.
Cheers, David.

If I understand the design concept of the “SimforceGT”-type right the main reason for pushing the shoulders rather than the butt is the limited strength of the actuators (SNC5) and the length of them → the don’t fit underneath the seat. You (bsft) don't have this limitation, I assume, as your “wiper” design is much more compact than an SNC and the motors are quite strong.

What you gain if you connect your wipers to the shoulders is kind of a higher gear ratio (load reduction) because you have to move the lever more for the same angle movement of the seat (see drawing; note: the angle of both vectors in the drawing is the same, so you would feel the same motion cue!) – at the cost of reduced speed of course. Don't know if this is what you want to achieve.
Back to your question about positioning the motors, I would recommend to mount them as far away from the pivot point as possible as this will better align the rod with the turning vector of the shoulder.

Well, actually I would recommend to position the motors below the seat and push it up. Because from a mechanical point of view the transmission of force is much better at the bottom of the seat than at the shoulder (when the drive mounted on the floor). This will most effectively induce the force (see alignment of lever and vector in drawing).

Thanks for the comments value1, I have had the motors in 3 different spots. Under the back of the seat, motors work HARD because they have to push weight, despite being on a pivot - the seat that is.
So I moved the motors to the front under neath, they still worked hard though.
I also tried them at the front and 200mm out to the side and connected to the top of the steering mount, they worked less hard again.
I had Eaorobbie advise me that leverage is the answer. So I am looking for advice on the best point of angle.
Yes actuator guys put them at the shoulders as actuators are not very strong, but the same applies even to motors.
On my old joyrider, the motor at the back of the seat didnt work that hard and stayed cool as it was connecting to a high point.
So after many mods to my current ride, I am going for motors at the rear .
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Similarly here: at the end it's about the power of your motor. You can optimise the mix of your movement speed, gear/lever ratio, the balance, positioning of the pivot, counterweights, etc. but you will need to move your 80 kg. I would be surprised by benefits from attaching your rods to the shoulder. But please let us know your experiences! :thbup:

Hi BSFT, after several tests with the distances and angles of engines, I came to this configuration, the engines consume less and give you better feeling
If you need some measure, let me know

Thanks for that. It looks about right. I should be ok with measurements. I am leaving my frame as is , being a frex style.
Cheers and thanks, hopefully the big worm gear motors I have do consume a bit less. They suck some juice!