World's Fastest R/C Car, anyone?

[Billfred]

Alright, so my interest in FIRST started with my interest in remote-controlled cars. (I'm working right now on building the longest, but that's another thread.)

I picked up a copy of Radio Control Car Action, and on the back page they issued a challenge. Build the world's fastest R/C car. For the rules (IIRC--I'll make sure later that I'm not missing anything), anything goes, as long as it's under two feet long, have some sort of 3D cockpit (something that it looks like a driver could sit in if it were full-size) uses driven wheels for propulsion (sorry, rocket guys), and has an FM radio with a fail-safe. (I'm pretty sure they'd live with an IFI system, even if it wasn't the best way of doing it.)

It'll be sometime after 6/1/05 out at Irwindale Speedway.

Now, with all of us fielding robots with four-speed eight-motor shift-on-the-fly gearboxes, you just KNOW that a couple of FIRST teams could whip up a mind-blowing car. The electric world record is 111 mph on 24 cells and a two-turn brushless motor.

Anyone mildly interested?

[Astronouth7303]

I don't think many of us have expieriance with fast, just powerful. (Correct me if I'm wrong). But I'll help through IM, if you ask.

[Elgin Clock]

Originally Posted by Billfred

The electric world record is 111 mph on 24 cells and a two-turn brushless motor.

Anyone mildly interested?

Is that speed scale mph?? Like how when new remote controilled cars come out for the holidays they say it has a scaled speed of 60mph.

Or is 111mph, an actual speed. Did a remote controlled car really go 111mph?
Wow.. That's 1.85 miles per minute..

Whoa!!!

[Astronouth7303]

It's like the land speed record. you point it and hope for the best!

[greencactus3]

Originally Posted by Elgin Clock

Is that speed scale mph?? Like how when new remote controilled cars come out for the holidays they say it has a scaled speed of 60mph.

Or is 111mph, an actual speed. Did a remote controlled car really go 111mph?
Wow.. That's 1.85 miles per minute..

Whoa!!!

yes, thats not sclaed speed. its actual speed... a 10:1 rc car scaled at 60mph is pretty slow i think.. not sure this is correct, but around 6mph??
that would be slow.
some rc cars go 70 outta the box..
how hard would it be to control 111mph rc car? i wouldnt even want to try it.
actually, i would, but id probably destroy it...
and rc cars at toys r us and whatever that come out at holidays are definitly NOT fast. get a nitro car... wish i had one...


and i am deeply interestred..

[Tristan Lall]

Try a 600 cc motorcycle engine, converted to run nitromethane! I could see 200+ HP being possible. (But the conversion probably wouldn't be easy....)

[ZACH P.]

Originally Posted by Tristan Lall

Try a 600 cc motorcycle engine, converted to run nitromethane! I could see 200+ HP being possible. (But the conversion probably wouldn't be easy....)

Lol, do you have a source for the nitromethane? 'Cause if you do...

[Tristan Lall]

No, I've never had the chance to get my hands on any. Nor do I know how such a conversion would be done--but I would imagine that a motorcycle drag racer would have something to say about this.

[Bcahn836]

That car would be very unstable. If you hit a pebble at that speed the car is going to roll, flip and cartwheel and never stop.

[Astronouth7303]

Originally Posted by Bcahn836

That car would be very unstable. If you hit a pebble at that speed the car is going to roll, flip and cartwheel and never stop.

Not to mention the nitro going boom.

[Billfred]

Well, that's the advantage of doing it at Irwindale: they keep that sucker clean!

And yes, that's straight-up, just-like-you-drove-it-in-your-car 111 mph.

Personally, I don't think it'd be that hard for FIRST teams to adapt to speed. I mean, we build for torque, since that's what's required to move a hundred-pound mobile goal. Change the gearing up, and while it won't be able to push much, it'll scream like anything.

Although the charges against the Nikko cars and the like would make for an interesting challenge...world's fastest Nikko, anyone?

[team222badbrad]

Yes that speed record is actual speed. This hobby is very expensive first off! Today many rc cars are very complex and yet simple pieces of fun! Some RC cars have 3 speed trannies and very small high powered engines.

I would not attempt to use the Mini Innovation First contoller (EDUBot). First off this would be very heavy! Second their is no need to use one! Third if your car crashed at 50 MPH is would no longer exist.

My RC truck (tmaxx) costs $400 bucks for the truck. Not to mention the batteries and chargers another $40. You also need other support equipment.
The fuel alone cost $23 a gallon. Imagine paying that much for it at the pump! yikes!

If you need anything just let me know.

Here is my truck. It goes 40 MPH out of the box. www.traxxas.com

[Ryan F.]

Drill motor, no gearbox, battery, and a set of wheels. Need I say more?

[sanddrag]

Originally Posted by rforystek

Drill motor, no gearbox, battery, and a set of wheels. Need I say more?

Not enough torque. Need I say more? Actually, I shouldn't jump to such a conclusion. You never said what size wheels you were using. But assiming you wanted to go 112 mph, you would need a wheel approximately 2" in diameter on the 19670 rpm drill shaft. Now, at stall the wheel would only be able to exert approximately 7.9 lbs of force on the ground. As motor speed goes up, torque goes down. So, I reckon moving at 112 mph (near 19670 rpm), you will have very little torque, certainly not enough to counter the air resistence.

Aside from that, I am fully willing to help with this project in any way possible if anyone will be working on it in the southern california area. While I've been fading from the hobby in recent years, I do have many years experience with RC cars and have 9 cars , both nitro and electric and have cutsom built frames before. This sounds like a fun challenge and I'm certainly willing to work with anyone who wishes to enter.

[Matt Reiland]

Originally Posted by Billfred

Now, with all of us fielding robots with four-speed eight-motor shift-on-the-fly gearboxes, you just KNOW that a couple of FIRST teams could whip up a mind-blowing car. The electric world record is 111 mph on 24 cells and a two-turn brushless motor.

Anyone mildly interested?

Hmmmm, My last car, (Kyosho Inferno Kani II) was pretty darn quick (~50mph with the OZ 2.5hp engine) but it was actually an off road car with a high stance and only a single speed. IF you wanted a really fast car, here is what one would have to do.

1.First, ditch the IFI control system, it is too big, too short of a range, and not useful for an RC car. Get a PCM radio that can cut your throttle if it gets out of range so you don't kill the person 3 blocks down the street from you when it goes by in a blur.

2.Create a Custom aluminum chassis based on a comercially available RC road car probably 1/8 scale which already hit over 70mph
http://www2.towerhobbies.com/cgi-bin...?&I=LXGAJ2&P=0

3.Take two .21-.26 race engines (~2.5-3 hp ea) and link them together like the Ofna Titan Twin. http://www2.towerhobbies.com/cgi-bin...?&I=LXFJB9&P=0
I can't see how you could get that much horsepower out of electric for even a fraction of the weight with the motors and batteries. (Take a look)
http://www2.towerhobbies.com/cgi-bin...?&I=LXEPH9&P=0
OVER 3 HP at 39,000 RPM!

4.Take the Automatic 3 speed from the Kyosho Mad Force http://www2.towerhobbies.com/cgi-bin...?&I=LXCGR3&P=0
and send it into a small custom high speed gearbox driving the front or rear wheels, such that the gearing uses the motors on the top end.

5.Tune in the steering servo for extremely dull steering input so that a tiny movement at 100mph doesn't launch it 30ft off course.

6.Add in a well supported body with some downforce so it doesn't take off like a jet.

If you can do all that, my guess is it will be pretty fast!!!!!