keyplayer said:
Come to think of it, I got a nice nosh off a mademoiselle in the grandstand, so maybe you're right.
Well the French are famed for their cooking I suppose...
Not sure what racing rotaries rev to, but I believe the RX-7 in standard guise redlined around the 8000+ mark (pre variable valve timing piston engines
![Eek! :eek: :eek:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
). Perhaps it revs higher because there aren't valves in such an engine.
The Honda S2000 worries me, redline at 9000rpm. That's just not right!
![Laugh :LOL: :LOL:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
I would love to hear one of those being properly wound up.
Did a quick calculation: according to the internet the S2000 has a stroke of 84mm. Now, at 9000rpm a piston is completing 150 full up-and-down strokes every second. So it is travelling at:
150 * 84 * 2 (cos it is up AND down) = 25,200mm/sec = 25.2 m/sec = 56mph.
But what about the accelerations? Well, I believe the piston would be moving basically in simple harmonic motion (I'm sure that isn't entirely true, but its near enough). Bear in mind it is nearly 1am and I am knackered so I will probably get this totally wrong (this will be embarassing if I get it wrong, SHM is the physicists equivalent of the two-times table
![Laugh :LOL: :LOL:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
)
Maximum acceleration at the ends of the stroke:
a = -(angular frequency)^2 * displacement.
So, our angular frequency is 2*pi*150 radians per second, = 942 rad/sec
a= 942^2 * 0.0042 = 3731 m/s^2
a = 380g... not as impressive as I thought it would be, certainly not at turbine impellor-tip accelerations. What does a piston weigh? Quite a force on the gudgeon pin!