So the Tesla is fast off the line, but all of those batteries are heavy AF. A drag strip is not that long however, only like a quarter of a mile at most. So the obvious question is, why are we not running plug-in electic cars down the track? Remove batteries, add an outlet and an extension cord, and you would go even faster! As a bonus, 1/4 mile cords would automatically unplug at the finish line, adding a measure of safety. You could put them on a special reel to wind back in after the race. I guess you could use overhead grids like a bullet train or a bumper car, but the cord idea allows you to kill power anytime in case of an accident. Plus, no need to wait to recharge. NHRA, get on this!
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Well, let's see. If the motors make 750hp total, that is roughly 560 kilowatts.
Picture the size of transmission lines needed to transmit 560kw of electricity across a quarter mile-plus.
So, basically, 1/1 slot cars.
The automatic shutdown with the safety disconnect is genius. Also, you could say the cars are actually powered by a nuclear power plant. I mean, I know my corded tools still kick butt compared to any battery powered cordless.
I think you're on to something here. I look forward to your demonstration run.
Pete. (l33t FS) said:
Well, let's see. If the motors make 750hp total, that is roughly 560 kilowatts.
Picture the size of transmission lines needed to transmit 560kw of electricity across a quarter mile-plus.
Oh and you'll need something to feed 1/4 mile of cord out fast enough so it doesn't unplug itself. I know buy an old funny car to trail behind pulling the cord!!!!
Can you imagine the holy mess that would be created if the car false started and suddenly a 1/4 mile of cable went flying out of the spool in 8 seconds or less?
Pete. (l33t FS) said:
Well, let's see. If the motors make 750hp total, that is roughly 560 kilowatts.
Picture the size of transmission lines needed to transmit 560kw of electricity across a quarter mile-plus.
*pulls up random voltage drop/conductor size calc*
Lets see. 560kw. Nominal voltage for Model 3 is 350, meaning ~1600amps.
Looks like approximately 10 1 gauge wires each way. That would weigh 337lbs per wire, so only 6740lbs of wire.
Although I suppose you could get the positive from one end and ground at the other, meaning one wire would be feeding out, while the other is retracting?
1:1 slot cars would be cool though.
An overhead pantograph setup like a train or something with ground contact would work, but either one will add drag.
nope.. you missed it. Electric motors spool up a big flywheel in the car. When the light turns green the cord disconnects and the inertia of the flywheel is all you have to get down the strip
In reply to mad_machine (Forum Supporter) :
Flywheels are heavy. One to turn a really quick 1/4 mile time would be insanely heavy.
Driven5
UltraDork
12/18/20 3:29 p.m.
In reply to mad_machine (Forum Supporter) :
...Until the first BAF grenades itself on launch.
There is a positive benefit of the trailing wire adding some directional stability. There is a negative to be considered of the wear on the insulation at the car end of the cable from dragging it back. Together they might be made into a betting game for the spectators, IE when will enough insulation be worn off to cause the exciting negative/positive display.
frenchyd said:
Pete. (l33t FS) said:
Well, let's see. If the motors make 750hp total, that is roughly 560 kilowatts.
Picture the size of transmission lines needed to transmit 560kw of electricity across a quarter mile-plus.
Oh and you'll need something to feed 1/4 mile of cord out fast enough so it doesn't unplug itself. I know buy an old funny car to trail behind pulling the cord!!!!
Can you imagine the holy mess that would be created if the car false started and suddenly a 1/4 mile of cable went flying out of the spool in 8 seconds or less?
Nah, just put a big generator on the funny car and run a short cord to the EV that way you don't need to spool it.
frenchyd said:
In reply to mad_machine (Forum Supporter) :
Flywheels are heavy. One to turn a really quick 1/4 mile time would be insanely heavy.
Looks like the above tesla would use about 6.2 MJ to get down the track (560kw * 11 second quarter)
Rough math says a 500lb flywheel 3 feet in diameter spinning at 7000rpm would do it.
yikes, that sounds scary
I've drag raced flywheel powered cars.
ProDarwin said:
Pete. (l33t FS) said:
Well, let's see. If the motors make 750hp total, that is roughly 560 kilowatts.
Picture the size of transmission lines needed to transmit 560kw of electricity across a quarter mile-plus.
*pulls up random voltage drop/conductor size calc*
Lets see. 560kw. Nominal voltage for Model 3 is 350, meaning ~1600amps.
Looks like approximately 10 1 gauge wires each way. That would weigh 337lbs per wire, so only 6740lbs of wire.
Although I suppose you could get the positive from one end and ground at the other, meaning one wire would be feeding out, while the other is retracting?
Perfect! Instead of motoring the tires, use a winch drum on the cable. Traction? Who needs it?
mad_machine (Forum Supporter) said:
nope.. you missed it. Electric motors spool up a big flywheel in the car. When the light turns green the cord disconnects and the inertia of the flywheel is all you have to get down the strip
Reminds me of the Good Old Days when people would bolt a 50 pound flywheel to their 265 Chevy or 221 Ford and launch and shift at 8000rpm, mostly using the inertia of the flywheel to accelerate them down the track.
At least, that's according to the old farts on other sites. Allegedly some people were spinning the 221s past 10,000. If so, those had to be some real mild-acceleration cam lobes to live with available 1960s valvetrain technology.
ProDarwin said:
frenchyd said:
In reply to mad_machine (Forum Supporter) :
Flywheels are heavy. One to turn a really quick 1/4 mile time would be insanely heavy.
Looks like the above tesla would use about 6.2 MJ to get down the track (560kw * 11 second quarter)
Rough math says a 500lb flywheel 3 feet in diameter spinning at 7000rpm would do it.
yikes, that sounds scary
heh. You know how airplane rotary (not radial) engines had a stationary crankshaft and the whole engine rotated?
This is possibly doable...
In reply to Pete. (l33t FS) :
At maybe 800 ? rpm . In a dive. I vaguely remember turning 2500 RPM as the catapult launched me. Maybe 2700 doing Rockets and bombs.
In reply to frenchyd :
You fought in WWI?
Rotary engines were only used for a short time, because of their odd layout, they were unthrottled and power was controlled by cutting spark.
I assume that by holding the crankshaft stationary and rotating the engine, there was very little vibration since the "reciprocating" mass was held stationary. Low vibration is probably really important when your biplane is made out of sticks and fabric...
Frenchyd is onto something. Look up outrunner electric motors. There's your flywheel right there.
