Thread: Audi LMP1 Discussion
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Old 2 Mar 2012, 16:33 (Ref:3034053)   #2767
gwyllion
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Originally Posted by knighty View Post
Interesting!......heres another feature on ther Williams Hybrid Power website:

http://www.williamshybridpower.com/n...-by-audi-sport
I posted that link yesterday: http://tentenths.com/forum/showthrea...23#post3033523 You probably missed it because of my overflow of posts in this thread

Sorry to correct you, but rotational kinetic energy is quadratic proportional, not linear, to the rotation frequency. See http://en.wikipedia.org/wiki/Flywheel#Physics.

If a flywheel stores 680 kJ at 36000 rpm (600 Hz), it has a moment of inertia of 0.0957 kg m^2. The same flywheel will store 1060 kJ at 45000 rpm (750 Hz).

This calculation is based on the assumption that Audi is using exactly the same flywheel as Porsche, but just spinning it faster. However on the technical drawing the flywheel looks more compact. So the flywheel might have a bit smaller diameter and/or weigh less.

BTW you got the 680 kJ from Race Engine magazine of August 2010. That number dates from the first hybrid 911. The 2011 version was more powerful: 2 x 75 kW instead of 2 x 60 kW electric motors.

Anyway this guess work is nice, but we will probably never know unless Audi tells us.
Last edited by gwyllion; 2 Mar 2012 at 16:51. Reason: I forgot a factor of 2π in my calculations
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