3DOF Racing Simulator

[Hmaia]

Concept layout

I am planning a 3DOF racing simulator operated by three SCN5-150, running X-Sim 3 and connected through a Devantech USN-RS485 interface.
I chose to add yaw because on e of the things i miss most in a fixed seat rig is the loss of rear traction feeling. By the time you see it on the screen it is too late o correct.
I have used the dimensions suggested by a post on the site, and the unit will be constructed using rectangular and square aluminum tubes.
I have a Logitech G25 and pedals, and use Rfactor, Rfactor 2 and GTR2.
I will be incorporating adjustable pedal support and steering wheel support.
I opted for movable pedals and steering wheel, but would consider fixed pedals and steering wheel instead, if the experiences of people who have built and used rigs are in favor of that option. Movable wheel and pedals seemed more natural to me.
This will be my first attempt to build something like this, and I would appreciate he evaluation and suggestion of the members of this incredible site. I have already learned a lot here.
Here are two images of the tentative layout

[sirnoname]

connected through a Devantech USN-RS485 interface

Better use the ones that are explained here for newcommers:
viewtopic.php?p=255#p255
They are faster and give more performance. Use one adapter for one actuator and avoid to decrease the throughput!

Fixed chair to wheel would be reducing the motion effect by 50%.

[Hmaia]

Thank sirnoname, for your input.
I have another layout, separating seat and steering wheel/pedals. I also incorporated adjustment (sliding up and down) to the rotational adjustment.
So, if I understand it right, I should use three Devantech USB RS-485 interface, one for each actuator.
With the setup I have here, and taking in account the actuator maximum speed of 400 mm/sec, I believe i can achieve 36 deg/sec for pitch/roll.
Would that be a good result. I see that CXC Motion Pro II claim 80deg/sec for pitch and roll (equivalent to 1.7 G).
I spent a day on a track driving a SPEC Racer Ford , and most of the turns at PIR where taken above 1G, and at the end of the day my neck hurt like crazy.
I think 1.7G for a long period of time would be very tiring.
I have a good template for a racing aluminum seat for which a one inch thick foam pad and cover is available with a final weight of about 7.5 kg. That should reduce the seat assembly quite a bit. I am 1.8 m tall and 90 kg.
I am trying to read as much as possible, and if this is a good layout, work on a full 3d layout, and refining as I go. I have devised a windshield wiper driven sliding mount for the pedals and will add it.

[motiondave]

I was going to comment on the degree of pitch , but you covered that.
Maybe less angle would be preferred. I found from my 2 dof sims, a move from wipers to bigger motors and the same degree of angle of lean on the frame made the experience a lot better.
Obviously everyone has a preference.
Oh , and just a suggestion , consider a Big motor like myself or floriske uses. That will really give you a jolt on the drift part of the frame.

[Hmaia]

I have done some CAD work for a better feel of this project. I an still not happy with it. The project, as it now stands will take a considerable amount of welding. I don't have a TIG welding machine and they are fairly expensive.
I have been considering the use of aluminum profiles, instead of welded aluminum tubing, and assembling using connectors and bolts. The initial cost of material and connectors may be higher than tubing, but the expense of welding, save a few parts, would be absent. I will soon do a cost study and decide the best approach.
Another consideration is the use of SCN5-100 instead of the SCN5-150. I have seen the SCN5-100 for less than $300 USD, whereas the 150 mm is currently priced at $505 USD.
It seems the 100 mm is the most widely used for professional made and DIY race simulators.
One question for most experienced members of this site, do they require the same positioning as suggested in one of the posts in the forum?
"Important minimum dimensions
30.50" (= ca. 77,5 cm) outer dimension from bottom-side ball-joint to ball-joint.
11.25" (= ca. 28,5 cm) outer dimension from top-side ball-joint to ball-joint
28.50" (= ca. 72,4 cm) from center of pivot to center of rear bar."
I am including here some CAD drawings, and again would appreciate suggestions and critic.

[Hmaia]

Here are some of the drawings


I have included adjustable pedal base (windshield wiper motor, and UHMW strips for bearing surface), fully adjustable steering/monitor mount, up and down and angular, and a keyboard support.

[Hmaia]

Thank you BobBuilt,
I really appreciate the quality of input I have received from this great site.
I am a Mechanical Engineer, but this is my first attempt to design something like this, and learning from other builder's experience helps a lot. I think that not being happy with the first, and sometimes the second design goes with the territory for engineers, and it gets worse when you yourself are the customer.
I will complete the cost analysis regarding aluminum profiles, and work on the switch to SCN5-100 mm.
It appears that my layout could work well, so I will try to keep the same parameters, after adjusting for the shorter stroke of the 100 mm SCN5.

[Hmaia]

Hello BobBuilt,

My first acquisition will be the seat. I will use the scale and plank method to determine the cg. I can seat down, keep my legs and arms in the approximate driving position, and have my ever patient wife read the scales. Once I have determined my cg, locating the the uni joint will be easy. Since these SCN5 can yield only 100N, overloading is a big concern.
Thanks again for the heads up.

[motiondave]

That is the same method I use mate. Will work nicely and yes look after your scn5 in the past we have had quiet a few fail only because of the in balance design people seem to follow. Keep us all informed and yes look after the wife they are the ones that let us spend all the funds on what they see is just a toy, its a passion to us, we all seem to catch that bug. Mine has commented on many occasions, I wish you would handle me as much as ya wheel, or you should have married that wheel instead of me. lol all good.

I will not comment......

[Roadster2]

I will not comment......

So your wife occasionally looks at your posts as well then Dave