1/5th Scale Bad Idea

[Oldway]

I think this class would be a bad idea it would raise the cost considerably. I know I would show up with a Honda CR125 engine with a 5 speed in mine. And if they kept it to 49cc and no transmission I would show up with some European Scooter motor with 60 horsepower.
My 2 cents.

[Sigurd Ruschkow]

I would love to see that car!

If you want to limit the cost of a car, size is not that important. You can spend 10 000 USD on a 1:10 scale car doing wind tunnel tests and buying special materials and special batteries and motors and buying over the best people over to my team.

I could easily spend 100 000 USD on designing 1:10
OR
a 1:4th scale rc car. If I had that money...which I do not.

If this is about limiting money, I would take out the company teams instead of limiting the size.


Sigurd


I think this class would be a bad idea it would raise the cost considerably. I know I would show up with a Honda CR125 engine with a 5 speed in mine. And if they kept it to 49cc and no transmission I would show up with some European Scooter motor with 60 horsepower.
My 2 cents.

[Chris LaPanse]

And what drive train could handle that? Also, how would it fit under a decently aerodynamic body? Even if 1/5 was allowed, electric would still take it.

[patcook]

I can sorta understand each side, as I was wondering what it would take to put yamaha's go kart specific 85 cc shifter caft engine into a 5th scale with a solid axle, and some aluminum rims to handle the rpms. As for power, a standard shifter cart will roast it's tires off the line with this same motor. I've also thought of a 50cc pocketbike motor, which can put out about 20 horse, if it is properly tuned, and it has a single speed clutch on it.

I can also see how an electric car could go faster because once you get the engine, gas tank, and all the electrinics on it, it would be hard to fit within a 1/5 scale chasis. an electric would be more viable due to the lower height and all that.

Maybe there could just be 2 classes. a normal class for all rc original equitment, and an all out custom competition where anything within the basic rules would go. a lighter chasis would be more efficient as long as it can get the power to the ground at startup. all it takes is a programable esc with a soft start programed in.

[Oldway]

What I'am really trying to say is that you can really do some damage with a big heavy model like the 1/5 and 1/4 scales. If you ever seen the carnage a 59oz 1/10 scale car can do at 80+mph you would think twice about putting something that big and powerful in the hands of someone who my or maynot be able or even qualified to control it at high speeds. I have seen nothing in the rules about driver qualifications, not everyone is as talented as Cliff Lett.
Just something to consider.

[MegaMe]

i think thats a very good point oldway... safety has to come first in an event like this...

i could be wrong but with say a gocart engine would you have big problems with the clutch burning out? ... if you have a multi speed gearbox it should be fine but with a single speed you have massively tall gearing - but still have to keep engine rpm's up enough so it dosent stall... seems like a clutch burning situation to me...

if you did have an go cart or mini-motorbike engine how hard would it be to put a multi speed tranny on it as well?

[patcook]

Yeah, I'd agree, safety is a big issue. One thing that will help out though is that it is at a real race track, so if everyone stays off the track when the car is running, it will only be able to hit a wall, and break apart, instead of having to wory about people and all that kind of thing. I'm sure many of the safety issues will be taken care of before the event even starts, in all the rules.

As for gokart parts, I know for sure that the standard caring clutch will handle more power than most motors can even put out. most of these clutches have to get a
250 lbs plus wieght going, and not a car weighing a lot less. I've seen even cheepy clutches that get put under a lot of stress (2 15 year olds on minibikes) last an entire year before the bushings gave out. all you really have to wory about is bearings, because the clutch is much bigger than a standard RC clutch.

It is also the same with shifter cart engines, which are sourced from dirtbikes, and just have a modified primary drive ratio so they can handle the much smaller tires.

Theoreticly all you would have to do is get a slipper in the middle of the drivetrain if you were really worried. All I would worry about is over heating the clutch, but if you geared it right so that top gear was geared the equivalent of even 1.25:1 you could get a speed of 142. that sounds stinkin fast to me. Of course if you really wanted to go crazy all you would have to do would be make it so that top gear was a 1:1 ratio to the wheels, and it would go about 180.

I can understand all the problems, and I would go, but money, and all that would be a problem for me since I am in college, and won't be able to get a job till this winter when I go home and start living at home again and working and going to school there, but if I had about $5000 to $7500 I would most definetly be there if not only to watch.

[cool head]

as i mentioned in another post. i think the event should have a buy out feature. if you car wins, it can or must be sold to the first bidder. something like $1500 should be a good figure. that way it will keep the competition from being a rich mans competition. i would hate to see some jackass with a bank roll thats never even driven an rc car win the competition cuz he hired a design crew to build him a world record car.

[cretin]

speaking of go kart style engines, how about a junior dragster alcohol engine? absolutely wicked power for a few grand.

[cretin]

not even bonneville records stand very long anymore. if some bob rieger kind of guy comes in and wins it, somebody else will outdo him next year.

[patcook]

Yeah, it's kind of amazing the ideas that people can come up with. I don't think the buy out idea would go far simply because there will be all sorts of teams competeing. No one would come if they just spent several grand, and then had to turn around and seel their car if they one. It's kinda like punishing them for doing all the work and everything to win. it's kind of a rip off.

One thing though is that you would have to get custom tires if you get to high of a horsepower. as an example, just look at the motoGP bike that race today. Most of them put out like 250 horses, but most of them are slow just because4 the tires can't handle it. sonthing lighter with a good power to wieght ratio will be better off any way. For an example, just look at the "ricers" (yeah, i ride rice) and their low wieghts, as compared to the big v-8 cars, and with the same power a smaller car ca just go faster. I know 1/5 sca;e could rock, but I don't see the point of putting a 50 horse motor in, and trying to gear it, when you can put like 15 or so horses into it, and go just as fast because it wieghs less, and it more compact anyways.

That's just my opinion. maybe there could be a class for simply hobby grade (designed with RC in mind from the beginning, not cheepy stuff) and then a class for cars that fit within all the rules, but used parts originaly designed for other things like gokarts and such. Of course, my car (if Icould even do it) would be something that fit the rules, but used a gokart shifter motor that was geared to top out at about 180, but i won't be there so I'm not going to whine about it for the next year when I'm not going to be there.

[patcook]

As for most people that say that they have a 50cc motor that puts out like 50 horses or something, I don't believe it. The most you can get is about 30 or so simply because to get a decent weight you the motor can't handle it. It would blow sky high before it even got half way around the track.

[patcook]

i'm not saying that 1/5 scale cars are a horible thing. Maybe there could be 2 classes like there are at monster truck races. Kinda like a small block and big block class. I still think that there should be a motor size limit though. Otherwise someone would come out with a sport bike engine in a 1/5 scale like dimension, and it really would blow up. I think that it should still be rc clas engines, and then other engines up to something like 100cc. It would keep it safe, but there would also be a lot of potential. Maybe this couls be a 2 day event on friday and saturday, and then use sunday as a backup day.

[promodvette]

speaking of go kart style engines, how about a junior dragster alcohol engine? absolutely wicked power for a few grand.

theres the ticket right there!! The newer higher end dragster motors are about 6 grand and make about 50 hp. Those things propel a 350lbs dragster 0-85 in 7.50 sec. Imagine what it would do to a 1/5 scale car that wouldnt weight 100lbs....

[Floppy]

I don't know why you guys even consider these things... you need to think about the ideas you have, they are not very acheivable goals.

..." Imagine what it would do to a 1/5 scale car that wouldnt weight 100lbs...." - The engine probably weighs half that, and the fact that it itself is probably 16 inches long, when the max is 24 inches. Why don't you go write a fiction novel on the idea?

wind resistance quadruples when size doubles, and im sure the engine your talking about is atleast 8 inches high. Arodynamic? i think not

There is no way you can make something, that has wheels, a 10x10x12 engine (just for example), controller, fuel tank, transmission of any sort, and pack it all into something 24 inches long. Good luck, if it even works ill be amazed! Once your done that, you can go design an aerodynamic body for it - an even harder task that i doubt you can do.

[patcook]

I understand what you're saying, but a 5 horse briggs engine will get a gokart up to about 60 stock. That's with a 250 or so pound weight in it, and the engine is highly inefficient. i've seen a 85cc kart motor with all the electronics and stuff it needs weigh just as much as a 5 horse briggs, and it puts out about 25 horses. My little brothers little 4stroke twin puts out less power than that, and it tops out at 85 or so, with a weight of about 400 pounds. I don't think drag will be as much of a problem as some people think with that size car. with that much power adn such i'd be more worried about traction. Even karts have that problem, and they definetly have a lot more weight to help them out.

[racerrandy]

I say if you want to build it and can make it according to the rules bring it on!
Less Talk, More Rock!!!!!!!!!!!!!

[Speedtester]

Isnt everyone here discussing 1/5 scale? Since when the heck is 1/5 Scale 24". You need to read through all posts before you try and bash the people here. Get a clue.


Tony.


I don't know why you guys even consider these things... you need to think about the ideas you have, they are not very acheivable goals.

..." Imagine what it would do to a 1/5 scale car that wouldnt weight 100lbs...." - The engine probably weighs half that, and the fact that it itself is probably 16 inches long, when the max is 24 inches. Why don't you go write a fiction novel on the idea?

wind resistance quadruples when size doubles, and im sure the engine your talking about is atleast 8 inches high. Arodynamic? i think not

There is no way you can make something, that has wheels, a 10x10x12 engine (just for example), controller, fuel tank, transmission of any sort, and pack it all into something 24 inches long. Good luck, if it even works ill be amazed! Once your done that, you can go design an aerodynamic body for it - an even harder task that i doubt you can do.

[racerrandy]

There is really no point in even talking about scale. A 1/5 scale motorcycle is probably under 24", so is a 1/5 go cart. Who cares about what scale it is, if you have an idea that can fit in the rules, build it. Thats the cool thing about this contest, you can strap a motor on a lollipop if thats what you want to do.

[DualBL]

are the rules being changed to 1/5 yet?
i know steve said they were revising the length, but has it been changed yet? what's the new maximum length?
thanks
-Nick