Steering upgrades for an open wheeled racer. 1

[Singleseater]

I am presently in the design phase of building a Maserati 250F reproduction incorporating modern advances in auto technology. One of the stumbling blocks seems to be the manual steering system. The original car used a worm and sector steering system common to so many of the day. The pitman arm was aft the firewall and a drag link connected it to a center link bellcrank routed next to the narrow I4 engine. Pitman arm offset from center was not significant. I will be using a wider, larger V8 engine directly forward of the firewall and would like to use a rack and pinion design which precludes the original configuration.

Having said that, using numerous steering shafts and U joints to input steering to the R&P will introduce slop equaling the worm and sector device and will more than likely introduce bind with the angles required. The optimal alternative would seem to be an offset mechanism at the firewall connecting the steering wheel steering shaft at center dash to a lower shaft inputing straight forward to the R&P.

Does anyone have knowledge of a proven method to transfer this input at the firewall without introducing slop due to chain/belt stretch or gear lash/bind? Chain and sprockets with tensioner comes to mind but the tensioner would need to be fixed to preclude tensioner spring introducing oscillation in the system.

Any advice greatly appreciated.

Brian

 

[GregLocock]

I'd be very leery of any such approach. Have you considered using CV joints in the intermediate shaft, rather than Hookes joints?

If you have to do it use a gearbox, with scissor gears to eliminate backlash.

There will be an interesting tradeoff between lash, friction and compliance in any system you design.

What do other people do in this situation?



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Singleseater]

Greg,

Thank you to refering me to FAQ731-376 as I now better understand the purpose of this wonderful forum. I have to go back and perform more research but my limited knowledge of this field of engineering left me somewhat at a loss for a more effective longterm solution.

I had considered intermediate shafting as my primary solution and had looked at the CV joints but had possibly made some incorrect assumptions when comparing freeplay in a CV versus a U joint. I will research this topic further. Do you know of any good technical documents which discuss steering system design? I would be glad to read.

Thank you again.

Brian Barnett