World's Fastest R/C Car, anyone?

[Max Lobovsky]

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....)

needs to be under 2 ft long

[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

[Maxzillian]

Oooooo, it's about darn time they decided to hold an official competition. I've personally been on the r/c scene for the last 5-6 years and have seen some pretty darn crazy creations. The following being two of my toys I've hand built... although the latter has been in the works for 4 years and still isn't done and the former has a little touch up work that needs to be finished such as strengthening the rear suspension and making battery mounts to hang the packs off the side of the chassis to keep the center of gravity down.
http://www.mtsquad.com/phpbb2/viewtopic.php?t=116
http://www.mtsquad.com/phpbb2/viewtopic.php?t=59

Anywho, I can't see a drill motor propelling one of those cars past 111. The brushless motor used in the record holding car would hit RPMs past 60,000 and still have power to spare. Hence why the latest craze on the r/c scene has been brushless motors. Compared to brushed motors they're over twice as powerful, more efficient, and more reliable. However, being a nitro guy myself I always ignore the new electric gadgets. Without a doubt, if you were to build a speed car, you'd need a on-road racing engine. Considering that the newest ones touch 3-4hp and still managed over 35k, I think they'd have enough power. The problem is taking that power and harnessing it in the most efficient of ways. So, and I almost hate saying this, the best drivetrain would be a belted drivetrain. With kevlar belts, it'd just barely be reliable enough to handle that much power. However, I personally think that a 2 wheel r/c vehicle would be the way to go. If you think about it, it's the most aerodynamic, stable (at high speeds), and efficient chassis design to use considering how little rolling resistane there would be. The only problem would be keeping the bike upright during the run while keeping it in a straight line. Perhaps a gyro to control a set of balance weights and some wires hanging off the side to act as training wheels? Either way, that's my two cents on the subject.

[Salik Syed]

forget piston engines
grab yourself a micro turbo prop engine...and connect it to the drive shaft.... search for wren micro turbines and you'll find it.

[RogerR]

they said that turbine power is allowed, and that made me wonder...what if you used a solid fuel rocket motor to spin a turbine? the only issue that i wonder about is rule #6

6. The vehicle must remain operable after its speed runs. Sacrificial motors or power systems that are inoperable after a run are not permitted.

would a spent rocket motor be considered a "sacrificial motor"?

the whole question is hypothetical, since i wouldn't know how to go about making this...i'm obviously out of my element.

[sanddrag]

Originally Posted by Maxzillian

Oooooo, it's about darn time they decided to hold an official competition. I've personally been on the r/c scene for the last 5-6 years and have seen some pretty darn crazy creations. The following being two of my toys I've hand built... although the latter has been in the works for 4 years and still isn't done and the former has a little touch up work that needs to be finished such as strengthening the rear suspension and making battery mounts to hang the packs off the side of the chassis to keep the center of gravity down.
http://www.mtsquad.com/phpbb2/viewtopic.php?t=116
http://www.mtsquad.com/phpbb2/viewtopic.php?t=59

That 6x6 is really awesome. Here's my coolest ride. http://team696.org/images/Mvc-018s.jpg I custom made the tube chassis. I did it when I was really young and I don't have it together anymore. The frame cracked in a few places over the years (I raced it you know) and I wanted to put it back into its original form. I also made a tube rockcrawler style chassis for my Clodbuster that is all together but I never got around to doing electronics and paint.

[Bcahn836]

Our school actually has a R/C car club, one of our teacher mentors is really into these cars. They race in the school parking lot and go off road with the T-Max then go back inside fix them and do it again. All of the members bring their own cars and just have fun. And most of them are on the robotics team which is cool.

[Maxzillian]

Sanddrag: Thanks. I love the sand rail. Personally I've wanted to build one for some time now but I never did get around to collecting the right parts for such a project. Now I can't tell from the picture so I'll guess. Is yours based off a rc10?

I wish our school had a r/c car club, but there really isn't enough inthusiasts in our school let alone the entire community to support such a thing. I personally know 3 people who have r/c cars, but none of them do it very often.

[sanddrag]

Originally Posted by Maxzillian

Sanddrag: Thanks. I love the sand rail. Personally I've wanted to build one for some time now but I never did get around to collecting the right parts for such a project. Now I can't tell from the picture so I'll guess. Is yours based off a rc10?

I'm glad you like it. I was going to put an interior of sort but I could not find properly scaled seats and didn't have the expertise to make them. It was based on Losi XXT.

As for this world's fastest challenge, I took a look around the Tower Hobbies website and here's what I came up with. The HPI Proceed looks like a very suitable platform for such a high speed car. I found that the Trinity Novarossi and Sirio racing engines have a claimed maximum RPM of an astonishing 44,000 and around 3 hp. With one of those engines and the optional gear set, the Proceed would have a theoretical top speed of around 134 mph. Now, in realityit would probably be considerably lower, more near the record of 111 mph. If there is some way to get another engine into a Proceed or make it use a 3 speed (like from the Kyosho Mad Force), it is possible to make a potentially wining car. Or maybe there's even a way to get two two speeds in series for four but I have a feeling for such a large space three would be sufficient. One disadvantage of the Proceed is that the engine is mounted transverselly, making it difficult to run a twin setup. Maybe something more like an 1/8 scal off road buggy chassis where the engine is inline and it would be easier to add a second one. Ofna has a car called the Ultra GTP that is like this but made for on road. I think Ofna even has a monster truck with two engines called the Twin Titan. Perhaps the engines could be swapped out and it modified for on-road racing?

The only bad thing about this contest is that RC cars cost so dang much and I haven't even heard of any sort of monetary prize. (Of corse having an RC car that goes over 100 mph would be a prize in itself)