Stupid idea, electric race saw

[shadco]

Reading thru the Future of Stihl thread got me thinking about this idea, a stupid, expensive one but could be fun.

I have this RC Heli motor just laying around, there are more powerful ones, this one is 7.3 HP continuous rated.





Paired with an electronic speed controller, think of it as an electric motor carb.



Driven using this type of battery 14 Cell 5000MAH battery.



This would not be like the turbine powered saw since the throttle response would be instant.

I have seen this type of setup pull 300AMPS burst from that battery pack which is over 50 volts nominal and 58 volts fully charged.

Would not be practical by any means but would probably be a fun project

Thoughts?

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[merc_man]

I like it. Git er done.

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[Hinerman]

I like it. Git er done.

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^^^^^ This. You may stumble across something and become filthy rich.

 

[cuinrearview]

@Armbru84 has dibs on the prototype.

You're welcome Cole...

 

[beaglebriar]

You could get creative and mount that shít in a clamshell pretty easy.

 

[shadco]

gonna haf to do some mafs to figure out gearing for starters. gotta figur out how to mount a rim to an 8mm shaft.

how many toofs on a normal bar tip? may haf to figur out gear reduction normal gear ratio for a heli is about 10 to 1 to get 2200 RPM of head speed.

My head already hurts.

.

 

[P.M.P.]

I got a old electric Remington and it's looking to kick some cant Azz...

 

[Al Smith]

Truth of the matter you can get real creative with electric motors .DC servo drives,permanent magnet motors etc .Years ago a company called "electro - craft " used two 40 HP DC servo motors to power a couple of municipal buses in I think LA Cal as an experiment that used regenerative generation that did very well using the technology of the time which has improved since .

 

[cuinrearview]

22k sounds about right

 

[shadco]

22k sounds about right

yep 22k at 80% throttle out thru the esc is where I run mine.

It's an out runner so the can spins which will complicate the mounting a little.

.

 

[Nutball]

I doubt 7.3hp continuously, but it at least has a fan. Burst power is more useful in a chainsaw race and 7.3hp is believable for a burst out of that size of motor. It might transient 300A, but over any usefully period of time, it will not work at 300A even as short as a second unless the motor has sensors.

 

[P.M.P.]

 

[shadco]

I doubt 7.3hp continuously, but it at least has a fan. Burst power is more useful in a chainsaw race and 7.3hp is believable for a burst out of that size of motor. It might transient 300A, but over any usefully period of time, it will not work at 300A even as short as a second unless the motor has sensors.

Actually that power train is designed for this type of use and they produce that power during the speed runs, not transient but sustained probably long enough to get thru a test log.

 

[Nutball]

There is a limit to the sustained amps a sensorless motor can handle. The limit is how many amps it takes to saturate the iron core with magnetic flux, then the speed controller can't get proper feedback to know what to tell the motor. Sensored would be the way to go. I'm just afraid that motor would saturate at about 120-200A

 

[Nutball]

I had a few of these made, they saturate at around 180-200A, can run around 6hp or so continuous, and can peak over 13hp. The only problem is it isn't as well designed for chainsaw use.

 

[Nutball]

Nobody here's thinking of building a 40kW electric racing chainsaw are they? Someone just bought out my motors.