🚀 go-pugleaf

In article <1gp2pdINN680@usenet.INS.CWRU.Edu> bj368@cleveland.Freenet.Edu (Mike E. Romano) writes:
>
>This flywheel discussion is interesting.
>I am not an engineer but note it was mentioned that a proper
>size flywheel can store the energy/power of a v8 engine.
>
>What is the simple equation here for energy (horsepower) stored
>in say a flywheel weighing 200 pounds, spinning at  1000 rpm?
>My last physics course was in high school.

Horsepower is, unsurprisingly, a measure of power not energy. A
viable unit for energy is the horsepower-hour, or the kWh. Using
the SI unit makes many calculations easier, but the magnitude is
sometimes hard to grasp intuitively for people used to English
units. 1 hp-hr = 0.74570 kWh or a horsepower is about 3/4 of a
kilowatt.

To calculate the energy stored in a flywheel, you need to know
it's mass, the distribution of that mass, and the rpm. If we assume
a 100 kg mass M as a point 1 meter R from the rotational center, then
the energy in rotating the mass is  

E=2*pi*R*M*(60*RPM)^2/3600
or in this case
2*pi*1*100*(60*1000)^2/3600=628318530.7J=174.55 kWh=232.73 hp-hr
or the energy equivalent of 0.73 gallons of gasoline.

Gary