hydraulic gear change

[Martin R]

Why do F1 transmissions use an hydraulic gear change and not pnuematic?, My reason for asking is that if you get a small leak with a pnuematic system it will not effect the system, wheas an hydraulic system will eventually run out of fluid.

[Wijs]

Tyrrell used to use a pneumatic system for the same reasons as you mentioned.

F1 cars have a hydraulic system to power the gearbox, clutch, diff, steering. Previously they also powered the active suspension, steering and brakes.

The pneumatic systems on the car are now only used to power the air valves in the engine.

Could a hydraulic system provide more power or faster response than a pneumatic system ? Could a pneumatic system be small and light enough to power all these functions ?

[rubinhothebest]

Hi, guys. I'm reading what you are talking about, with all that convinction about pneumatic systems, but, could anyone tell me what does it consist of? I just konw that penumatic sys allowed F1 teams to make their engines work a lot faster, I suppose it is because of something....

[Martin R]

Overall hydraulic systems can produce more power but all the systems that you mention with the exception of steering can have pnuematic control on trucks in the 'real' world (reactive rather than active suspension). The only minus point I can think of is size e.g. the hydraulic pipe would have a smaller diameter for the same use as the pressure in an hydraulic system would be much higher and the valve bodies would need to have smaller ports,(not necessarily a lower weight though as you do not need a return line or fluid reservoir). I had forgotten about the power steering on modern F1 cars, that might be difficult using air (I have never heard of anybody trying it), although electric power steering could be used.
To answer rubinhothebest question you would have a compressor, with a method of controlling max pressure, control valves sending the air to either a turbine (rotational movement) or piston (linear movement) Obviously in an F1 car the valves would have electronic control, in terms of what it does in a current engine, it allows the valve gear to be operated with more flexiblity than with just a camshaft, giving a wider spread of power, thus an easier car to drive. Sorry don't know exactly how it works.

[Martin R]

I stand correcting myself on air valves, read the following:
http://www.bath.ac.uk/~bspahh/rasfaq/node84.html