Stream Liner Suspension

[maguromic]

Just curious what some of the stream liners are running for suspension.  Are they straight axle style with shocks or as some I have seen independent suspension?   What are the advantageous running a independent system versus straight axle style with shocks on a liner?   I thought I saw on Sumner's page some where the Speedway Motors liner and it had a indipendent front suspension. 

 I don't want to get into a debate over solid mounted versus suspension, so can we keep this thread on suspension?

[Sumner]

Just curious what some of the stream liners are running for suspension.  Are they straight axle style with shocks or as some I have seen independent suspension?   What are the advantageous running a independent system versus straight axle style with shocks on a liner?   I thought I saw on Sumner's page some where the Speedway Motors liner and it had a indipendent front suspension. 

 I don't want to get into a debate over solid mounted versus suspension, so can we keep this thread on suspension?

Sum

[maguromic]

Thanks Sum, thats the picture I was referring to.
Tony

[Peter Jack]

It looks to me like they severely limit the suspension travel. The gold block at the front appears to have four adjustable suspension stops set rather close to zero travel. In any other form of racing a solid stop would be considered very upsetting for the suspension and would probably cause severe sudden handling issues.

Pete

[SPARKY]

Peter---I know you didn't ask for soild---but the suspension travel needed on a coarse that the faster cars are INTRESTED in running  on is practacatically nothing---figure how far a car travels in a 10th of a second  at 300+ and figure the reaction capability of even the electronic shocks---

[Dr Goggles]

Peter---I know you didn't ask for soild---but the suspension travel needed on a coarse that the faster cars are INTRESTED in running  on is practacatically nothing---figure how far a car travels in a 10th of a second  at 300+ and figure the reaction capability of even the electronic shocks---

Nice one Chapeau Bleu ( yeah that's you Sparky )absolutely...something in my mind keeps me coming back to this....despite  little track experience, limited engineering know-how when it comes to shock absorber technology and no idea what soild means ,during the build of our car I argued a lot with people about the relevance of springs and shock absorbers to what we were doing and I'm thinking more like 200,let alone 300. I kept seeing a wheel failing to follow the ground because the spring rate and the dampening could not form a relationship that would track it at such high speeds....and as I've always said ...............

NO SCIENCE IS BETTER THAN BAD SCIENCE

[Dean Los Angeles]

You could be right that no type of active suspension could react to the active dynamics at 300 mph. But it isn't all about high frequency reaction. Look at the tracks from the Burkland liner. Low frequency dynamics, in this case bouncing, also come in to play. Any suspension beats nothing. Even if this surface was laser flat, long vehicles can still bounce through the reaction to throttle, brake, steering and parachute.

Shock absorbers absorb . . . shock. Damper is a better word. Take the shocks off of your car and drive around. A small bump sets off a reaction that goes on a long time. The shock on the streamliner helps damp out those reactions.

[SPARKY]

Dean, you are correct virtually everything has a natrual frequency---In walking the 1 mile to the 3 several times, I have seen more uneven tire marks on the salt apparently caused by torsional roatation of the chassis----some apparently caused by some pretty well know cars---front and rear not--- 411

[Rex Schimmer]

I agree with Sparky that torsional oscillations can certainly occur in land speed cars. Most landspeed cars have frames that are very strong in bending, i.e. when acting like a bridge, but not much stiffness in torsion. The pics of the tire marks from the Burkland car would certainly seem to show some sort of torsional oscillation. The JCB streamliner did consider torsional stiffness if you look at the large CNC machine cover plate that covered the engine bays.

Rex

[Peter Jack]

I've done some thinking on building a small streamliner and the approach I've considered was to use a beam axle at each end suspended by preloaded elastomer pucks. They could be rubber, urethane etc. This would give very limited travel and be somewat self damping if the right material is chosen. One puck above and one puck below would allow the very limited travel without the jarring stops. Just my thoughts.

Pete

[Dr Goggles]

I've done some thinking on building a small streamliner and the approach I've considered was to use a beam axle at each end suspended by preloaded elastomer pucks. They could be rubber, urethane etc. This would give very limited travel and be somewat self damping if the right material is chosen. One puck above and one puck below would allow the very limited travel without the jarring stops. Just my thoughts.

Pete

...that kind of describes our front end.....but there is some axle flex that is undampened which I'm not completely happy with.

[1212FBGS]

man.... somehow we got on the suspend or not to suspend subject again
kent

[maguromic]

man.... somehow we got on the suspend or not to suspend subject again
kent

Getting back to suspension, does any body know what the front hubs on the Speedway liner from or for what spindle they were fabricated for?  Or was it front wheel drive?

[SPARKY]

I have seen alternating salt divots, on extremely good salt years as well as not so smooth, left by cars that have may have front supensenion that do not have the benefit of suspension and shock absorbing punematic tires profide.  Something is causing the alternating pattern. Either the suspension cannot handle the extremely sharp high frequency inputs and it sets up an ocilation or the chassic is rotational flexing or BOTH.  I have also seen the same alternating pattern left by rear tires leaving chirp marks under power as alternating spinning tires, that are aparently lifting completely off the ground.  This is  due to tire hop allowed by chassis ocilation or something in the suspension not preventing axel ocilation side to side.

[Ron Gibson]

John Mckichan designed and machined the hubs and wheels. The hubs use needle roller bearings with a thrust bearing for end play. With synthetic grease there is no sign of heat, even after a 300+ MPH pass.
As far as the control arm travel mentioned. The stops are set to "0" for transport. Don't remember how much travel for racing.

Ron Gibson, Omaha NE