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Old 12-25-2008, 08:51 PM   #16
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ya the rpm on a cars are alot lot higher than any plane or heli.
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Old 12-26-2008, 07:45 AM   #17
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The load on the rings is from the G's like you said.....but that deosn't mean it can't work.

The speed of the piston and rpm create the G' load, right. But so deos the weight of the ring (momentum).

A 450cc dirt bike can spin its large piston to 10,000 rpm with a much longer stroke. More stroke = higher piston speed= more g force.

I'll bet that a Honda F1 race car turning its 20,000 rpm has a higher piston speed than a .21 going 35,000 rpm. Heavier components as well (more momentum).

It could work but it would wear just as fast as Abc construction so whats the point. It might be hard making tiny ring grooves in a piston as well.

And I'll bet with some work we can get a whole lot more RPM out of a Saito or OS 56 size 4-stroke. Airplane engines aren't exactly desighned for pushing the limits like a race motor.
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Old 12-26-2008, 07:49 AM   #18
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An even better option would be to develop higher torque/lower rpm motors for our uses and gear accordingly. Then we can get far better driveability and engine life out of our stuff. There's a guy in the engines forum that's using a .26 4 stroke in a 1/10th stadium truck with great results.
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Old 12-26-2008, 08:25 AM   #19
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Yeah that'll work to. A little more Rpm say 15-18,000 is doable. There was a truggy somewhere on here that had a .56 OS. He used buggy diffs and more pinion gear it seemed. May need some Mods to fit all that gear.

These engines allready have a ton of torque, just need one desighned from the ground up as a race engine. Probally only need a cam and valve spring change. Not sure how long valves would last before stretching to 0 lash.

First major engine comapany to make a viable 4 stroke for 1/8th scale is going to rake it in. Especially since 1/8th is changing so much recently. (Electrics) And its lame having 12 identical cars on the track. Four strokes should be easier to control wheelspin as well. Despite the torque hit.
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Old 12-26-2008, 03:37 PM   #20
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Blow-by also becomes an issue when the engines get smaller since the crankcase has so little volume to begin with. The rings never seal perfectly and even a little amount of blow-by will affect a small engine.
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