Ttowntoolman

Sorry I did not wanna stop the discussion, just was processing the snowmobile influence and put down what came to mind. Having a drive and driven clutch would enable you to tune our engines into a specific rpm range, exactly what a two stroke is good for. If you could keep the engine turning at the rpm that it makes the most tork while it is propelling the car/truck to it's max speed would be ideal in theory. This was a responce to the 4 speed idea, which aint that bad of an idea. Just seems like to many moving parts to me....

Anthoop

A member of this forum (ziggy12345) tried CVT on a nitro speed car, the CVT was made by a Canadian guy who makes them for snowmobiles, the problem was powerloss. The type of system he used had the sprung loaded pulleys and vee belt (I am not sure if there are other variants), by design the belt will more or less constantly be splipping...only a small amount but that small amount will be more costly on our engines.
I have to ask the question of why would you want/need four gears, if you are adding more gears why not have five/six/seven....? (picture by ziggy)

Ttowntoolman

Yea and any slip at these rpms would just eat belts like nothing. Besides the cost of the drive and driven pullies most likely will cost more than the model we wish to propel.

Foxy

I was going to mention CVTs as well, but guys, the problem here is that we are discussing a future technology to support a future technology, to improve a dying technoology (combustion engines). I'm all for discussion, but even if we hit on the perfect solution (someone manages to come up with at least a working theory on nitro turbo, and then subsequently a transmission that can keep it in the powerband), it's going to take many years to bring it to market. In say, 7 years, brushless technology will have reached insane levels, it already outstrips one of the most mature technologies we know of (combustion engines), and it's still in its infancy.

So yeh, all nice theories, but we are never gonna see this stuff in the hobby, on a shelf. It's too late now.

phmaximus

Imagine a CVT on a brushless setup, I could limit the RPM to keep it nice and low right at the max torque of the motor,

savagecommander

keeping an electric motor in its torque band draws high amps. amps=heat, so operation on a constant basis in that area of its powerband would be a waste. utilize the CVT reduction to provide the torque needed with minimal motor current.

so we're done with turbos now?

Ttowntoolman

so we're done with turbos now?
[/quote]

Just resting our fantasies for now.....

phmaximus

Im not seeing ur point can u explain it clearer?

I allways thought the CVT, transmissions were ment to keep the motor neer its max torque...
a brushless motor is like a petrol motor, more heat is created in its sweet spot, so what? increase the cooling system
rember volts x amps = power.... the hotter it is, the more power its been putting out

Dont know why u would use a CVT for reduction, brushless motors have pleanty of torque, might be use full for a crawler....cant see how?
I can see uses to use it as a overdrive, u could get something extreemly fast

savagecommander

volts x amps=power, but there are a host of other formulas that come into play that you are neglecting. no, a BL motor is nothing like a petrol motor- BL torque is proportional to current, maximum current is at stall. Yes, a hotter motor means more power, but that doesnt directly relate to the motor converting that energy onto mechanical work.

Foxy

Indeed. Heat is in fact loss. At peak torque output an electric motor is least efficient.

Whether or not a CVT (or in fact any kind of rtransmission) would be of benefit to an electric system depends on the electric system. A massively torquey, low rpm system would obviously benefit from a gearbox to give amore usable range of rpm at the driving wheels, however a less torquey high rpm system, may not benefit at all, due to the fact that electric motor torque is almost linear.

savagecommander

For one thing, it would eliminate the huge startup spike, and if you had the right combination of motor/CVT you could keep motor rpm almost constant. that would keep current draw constant, increase runtime and efficiency

flyingaardvark

I know I'm a little late in asking, but wouldnt simply raising the inlet ports above the exhaust ports allow you to boost a motor?

phmaximus

Ahhh not this again... Lol