World's Fastest R/C Car, anyone?

[Tristan Lall]

Originally Posted by maxlobovsky

needs to be under 2 ft long

I thought someone would bring that up.

If I really wanted to be picky, I'd point out that there was no (stated) restriction on how wide the thing was--so mount it in a transverse arrangement.

Also, if you slightly tilted a standard v-twin or a very compact 4 , you should be able to make it fit within 2'. Problem solved.

And if that's too big, use an 85 HP competition go-kart engine. (Uses 100 octane racing fuel, no less, so it's a little safer....)

[ebmonon36]

I think that the speed record is for cars using the rc car race people sanctioned (im forgetting the acronymn) parts so I think go cart engines are out. The one that set this record if I recall correctly was build by Associated employers and could have gone much faster if it hadn't crashed into the wall at the track they were racing it on. ....it would put my Kyosho Turbo Ultima (circa 1987ish) to shame.
Eric

[sanddrag]

Originally Posted by ebmonon36

it would put my Kyosho Turbo Ultima (circa 1987ish) to shame.
Eric

You ever heard of a Panda Danny Thomson's Stadium Racer? Probably not. It has a little Thunder Tiger .10 engine adapted for the truck. It is the most POS RC car I have ever owned. Its brake is a piece of cork bonded to a brass strip that is bent over by the servo and rubs on the clutch bell. I bought it because it was only $50 brand new in the box and it was old and rare. It has a really cool body though...

Ah, I love RC cars. They are so much fun sometimes.

Just a quick story on the importance of failsafe mechanisms. I was once driving my Traxxas Nitro Stampede with my JR XR3 FM radio. The AA battery holder in the radio had a crack, but once it was put in the radio it all seemed to sandwhich together okay and it still worked fine. Well, this one particular day, I had the engine all tuned up for maximum performance. Just as I was making a full speed run dead center down my street, the craked part of the battery case in the remote breaks even further, the transmitter batteries lose contact with the terminals, the radio loses power, and the servos stay in their WOT and dead ahead positions and the truck takes off screaming dead down the middle of the street at 30+mph. It goes a full block until it comes to the intersection where it crosses the street and runs head on into a curb at full speed. But that is not all. It bounces off and makes a right and goes up the other street. At this point, I can't see it because it is no longer on my street but I can hear it's engine still screaming at WOT. After it goes up a block, it hits a curb again, somehow makes a U turn and starts heading back down the block it went up. Finally the front end is falling apart and it veers to the right back into the curb it hit the first time where it finally flips over. I thought that when flipped over, it would run out of gas and the engine would shut off, but no. From being so shaken up, the fuel is all filled with air bubbles and the engine is runing in an extremely lean condition. As I ran up to it, one tire was stuck against the curb but the other was in the air and it looked like a pizza cutter it was spining so fast. It must have been stretched out to 10" in diameter. The engine was screaming at such a high pitch and rpm I thought it was going to blow. It was the loudest sound I had ever heard in my life. When I was finally able to shut off the engine by putting my thumb over the air filter, there was the greatest silence I had ever heard in my life. Luckily, it somehow managed not to hit any houses, parked cars, mobile cars, animlas, or people.

And that my friends is why it is important to have failsafe mechanisms.

[Scooter]

If it were me, I'd take a .46 size engine off of one of my r/c airplanes and strap that in with a little centrifugal clutch, and gear it down....just a little....these motors have decent torque and a uber high top end rpm of 20k rev/min. If you put that to a big set of wheels, you'll have one heck of a car. I would also do the steering so that it has a very small range of movement, thus increasing the controlability of the car (you could also set in dual rates on your x-mitter).

Whaddya think? Could it work?
-Bill

[Greg Needel]

just FYI here are the offical rules of the challenge

http://www.rccaraction.com/rc/news/car_challenge.asp


and here is the set up for the car that has the current record

http://www.rccaraction.com/rc/articles/need_speed.asp


I aslo found this RC fourm with alot of information in their thread

http://www.radiocontrolzone.com/foru...d.php?t=167401


my brain has been running circles around this project since i heard about it

[sanddrag]

Originally Posted by Scooter

If it were me, I'd take a .46 size engine off of one of my r/c airplanes

I think Thunder Tiger already makes a truck with a .70 helicopter engine. It goes fast, but not 112+ fast. Perhaps that's because it is a monster truck and geared for torque.

But an airplane engine is an interesting idea. They rev almost as high as the car engines but come in much larger displacements. It may be difficult adapting a clutch though.

[team222badbrad]

It may be difficult adapting a clutch though.

I would not bother even using a clutch! I would just make the thing direct drive. You would just have to implement some kind of remote kill switch (micro servo?)

If I were to build anything I would definitaly built a car with an engine not a motor!

Batteries are too heavy

[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!!!!!

[sanddrag]

Matt you make it sound so easy. It will be quite difficult to make all those components work together but it can indeed be done. As for the horsepower of that engine, I've read sever articles claiming that the way manufacturers come up with that rating is different between each company and it is not a uniform system of measurement/testing. Your 6 step plan would make a pretty fast car. How fast? I don't know. One thing is that nitro engines can not run at WOT for too long or they'll break the con rod or sieze or blow a gasket or whatnot, not to mention possibly overheat. But it might be possible for just getting to top speed and back down really quick. It would depend on the gearing. Also, the speed and power you can get on them depends largely on several factors such as air temperature and humidity, fuel composition, etc. You would need some really good tires and a body and components because of the forces involved with such high speeds.

Even with all the challenges, I would like to try this.

What does everyone think of a dragster style car with just a really fast electric motor with a pinion, an axle with a spur and wheels, a _______ load of batteries?

Or would a pan car type car be better or would a sedan?

Is larger better or no?

So many questions.

[mechanicalbrain]

the fastest rc i believe was a corvette (the car not a model) running on remote control!

[Jeff K.]

I was reading this older issue of Extreme RC Cars and in the "Racers' Rides" Section, which was the cars of the subscribers. One guy had built a 1/8 on-road car that started as an Inferno 7.5 using a mill, lathe, and CNC machines. It has a Hacker C50 Maxx motor and 12 cells powering it. It also has a custom 3-speed gearbox and has been radared at 92 mph.

Maybe instead of nitro, howabout dual brushless?

[sanddrag]

Originally Posted by Stonefan5271138

Maybe instead of nitro, howabout dual brushless?

Great idea, but may I suggest tripple brushless?

[Jeff K.]

Originally Posted by sanddrag

Great idea, but may I suggest tripple brushless?

LOL OOH Shweeeet

Geared way up at like, almost 2:1...but it would have little to no torque and would take a long track to reach top speed...Or am I wrong? I don't know much about brushless, but I have a 10 turn motor on my Team Associated TC4 with a gear ratio of about 5:1...I may be wrong but it takes just 15 feet to reach top speed.

I'm thinking about maybe going brushless soon, does anyone have like, any reasons why I maybe shouldn't?

[sanddrag]

Originally Posted by Stonefan5271138

I'm thinking about maybe going brushless soon, does anyone have like, any reasons why I maybe shouldn't?

Cost! They aren't cheap. But they sure are smooth and reliable.

[Kyle Love]

Don't they have racing ones that go around 120-150?