Lightend Rotors, Worth The Efort?
10-26-06 | 08:40 AM
#27
There is no such thing as free energy. The 10 mph gained during a shift would have to come at the expense of lower acceleration while in a gear, getting the heavy flywheel spun back up.
The acceleration burst gained during a shift would be an advantage if a racer was using a wide ratio gear box; maybe it would help get you back up in the powerband sooner. I don't think it would be much of an advantage with a close ratio racing transmission.
The acceleration burst gained during a shift would be an advantage if a racer was using a wide ratio gear box; maybe it would help get you back up in the powerband sooner. I don't think it would be much of an advantage with a close ratio racing transmission.
10-26-06 | 04:58 PM
#28
Full Member
Joined: Mar 2005
Posts: 60
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From: London, UK
Interesting comments above.
A F1 car has a combined clutch flywheel assembly of about 3-4lbs with a rotational diameter, until recently of as little as 4".
My 82 RX-7 Grp-1 racer has a 11lb steel flywheel with a 7.5 twin plate clutch 20lbs in all.
A heavy clutch or rotational inertia in no way helps a racer down any straight, in fact is slows down changes, it does require a little skill with a light setup to keep the engine at the correct speed - a little practice maybe.
Indeed changing the prop/drive shaft from steel to composite (GKN) makes a significant difference.
Serious power machines such as drag racers have a different requirement. Their clutches, or clutch packs, are highly sophisticated, albeit using hydraulic valve timing rather that electronics (Rules), mechanisms that allow a significant but controlled slippage...THEY GENERATE HEAT and guess where a lot of it goes...the flywheel facing.... use a 7lb steel faced alloy flywheel and it won't survive the burnout.
Best material for handling the heat is good old Iron and lots of it to prevent wharping.
There is no real time to cool/ventilate the system so it needs to cope with about 700kW for a 10 seconds .. ok only a % goes into the flywheel, unless the clucth timing is wrong, but thats a bit hot
Make all the rotating masses as small a diameter and a ligt as you can unless you have other constraints.......$$$$$ (my biggest), rules, strength, heat capacity, vibration etc
Y
A F1 car has a combined clutch flywheel assembly of about 3-4lbs with a rotational diameter, until recently of as little as 4".
My 82 RX-7 Grp-1 racer has a 11lb steel flywheel with a 7.5 twin plate clutch 20lbs in all.
A heavy clutch or rotational inertia in no way helps a racer down any straight, in fact is slows down changes, it does require a little skill with a light setup to keep the engine at the correct speed - a little practice maybe.
Indeed changing the prop/drive shaft from steel to composite (GKN) makes a significant difference.
Serious power machines such as drag racers have a different requirement. Their clutches, or clutch packs, are highly sophisticated, albeit using hydraulic valve timing rather that electronics (Rules), mechanisms that allow a significant but controlled slippage...THEY GENERATE HEAT and guess where a lot of it goes...the flywheel facing.... use a 7lb steel faced alloy flywheel and it won't survive the burnout.
Best material for handling the heat is good old Iron and lots of it to prevent wharping.
There is no real time to cool/ventilate the system so it needs to cope with about 700kW for a 10 seconds .. ok only a % goes into the flywheel, unless the clucth timing is wrong, but thats a bit hot
Make all the rotating masses as small a diameter and a ligt as you can unless you have other constraints.......$$$$$ (my biggest), rules, strength, heat capacity, vibration etc
Y
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