moustrap car woes! - RC-Monster Forums

t-maxxracer32 · **moustrap car woes! -** 09.15.2007, 08:33 PM

hey guys i need (well my freind needs to) build a mousetrap car! he came to me since i kne a little about rc cars... and it didnt help much. i got the basic design of it but i just dont knwo how to make ti move! we have 3 more mousetraps so if this design isnt gonna work then let me know!

maybe i can get another set of popsicle sticks on the other side and put another allen wrench in and make it both rear wheel drive. idk!

thanks for any help!

_paralyzed_ · 09.15.2007, 10:49 PM

strip a micro t and use its parts, are you serious about this, if so, can i ask why? mice on speed? perhaps a way to terrorize kittens? a really really bad drunk?

mach1stang · 09.15.2007, 10:53 PM

why not put a sail on it so when the trap goes off it would be like a fan?

_paralyzed_ · 09.15.2007, 10:54 PM

oh, the spring powers the car, d'oh! use a hollow tube the width of the trap and leave enough axle between the wheel and trap to wrap the string, instead of the allen wrench, ooh, ooh, run dual tires on each side, but only put a wheel on the outside, wrap the string around the wheeless tire, higher gearing!

What's_nitro? · 09.15.2007, 10:56 PM

You should just use all 3 mouse traps to throw a Hot Wheels car down the track. Technically, it would be powered by the mouse traps.

jhautz · 09.15.2007, 11:13 PM

wrap a string around the axle and tie the end to the spring loaded bar. When the trap is triggered it will pull on the string and unwind it from the axle and make the alxe turn which will make the car go.

Does that make sense?

What's_nitro? · 09.15.2007, 11:49 PM

I assume the contest is for maximum distance? Just make sure the string doesn't rewind after it unspools.

Patrick · 02:09 AM

Is this for school? I had to do one in year 8. Mine won at my school, so I got to go to a completion against about 15 others schools. It was good, because I got to go during school time. I think I came about 5-7th out of about 15-20 or so, I think.
It was a 15 metre race, we had to use the mouse trap we were given, and it had to be less than 500mm long I think.
Mine was long (close to 500mm) with some cardboard wheels (they were bought round, mum had them for putting cakes on) that were about 200mm in diametre. The top few cars had CD's as wheels.
You've got the right idea of using a long lever attached to the spring, but you want the axle to be behind the end of the pop stick when you have it fully pulled back, otherwise there will be some slack in the string when you let it go.
I had a thin aluminum tube for the axles, with a small hole drilled in the centre of the rear one. I put a small bent nail in the hole for the string to attach to, just make sure the nail comes out of the hole when it gets to the end others wise it will lock the axles up. Make sure to wind the string up tight and in a way that it won't get tangled.
Use bearings on the wheels. Have the rear wheels connected. Put the string in between the rear wheels, not on the side, so the string doesn't interfere with the wheels. Keep it as light as possible.
The main things you need to change is to make it longer and use bigger wheels, I recommend CD's, especially for the rears, fronts don't matter as much, as long as they roll well and are light.
Depending on the length of the race you might need to tune the length of the pop stick to get the best mix of acceleration and top end.
Oh, and make sure it's not going to tip over in the race like a couple of the others did

I knew that what I learned from mouse trap racing would come in handy one day.

t-maxxracer32 · 09.16.2007, 02:21 AM

Quote:

Originally Posted by jhautz

wrap a string around the axle and tie the end to the spring loaded bar. When the trap is triggered it will pull on the string and unwind it from the axle and make the alxe turn which will make the car go.

Does that make sense?

makes perfect sence but pics would help! hahaha! thats the basic design but i just couldnt figure it out...

t-maxxracer32 · 09.16.2007, 02:22 AM

o ya yes patrick is it for school! it only has to go 10 feet but any more than that is extra credit

BP-Revo · 09.16.2007, 02:24 AM

My brother had to make one, its quite simple really.

Take a long pole and attach it to the flip part of the trap, and then attach a string on the end of the pole. Wrap the string around the axle of a set of a wheels.

As the trap flips, it will pull the string, spinning the axle and ultimately the tire making the car move.

The long rod just helps you get more movement since the mouse trap will only pull the string a couple inches without an extension.

t-maxxracer32 · 09.16.2007, 02:24 AM

Quote:

Originally Posted by Patrick

Is this for school? I had to do one in year 8. Mine won at my school, so I got to go to a completion against about 15 others schools. It was good, because I got to go during school time. I think I came about 5-7th out of about 15-20 or so, I think.
It was a 15 metre race, we had to use the mouse trap we were given, and it had to be less than 500mm long I think.
Mine was long (close to 500mm) with some cardboard wheels (they were bought round, mum had them for putting cakes on) that were about 200mm in diametre. The top few cars had CD's as wheels.
You've got the right idea of using a long lever attached to the spring, but you want the axle to be behind the end of the pop stick when you have it fully pulled back, otherwise there will be some slack in the string when you let it go.
I had a thin aluminum tube for the axles, with a small hole drilled in the centre of the rear one. I put a small bent nail in the hole for the string to attach to, just make sure the nail comes out of the hole when it gets to the end others wise it will lock the axles up. Make sure to wind the string up tight and in a way that it won't get tangled.
Use bearings on the wheels. Have the rear wheels connected. Put the string in between the rear wheels, not on the side, so the string doesn't interfere with the wheels. Keep it as light as possible.
The main things you need to change is to make it longer and use bigger wheels, I recommend CD's, especially for the rears, fronts don't matter as much, as long as they roll well and are light.
Depending on the length of the race you might need to tune the length of the pop stick to get the best mix of acceleration and top end.
Oh, and make sure it's not going to tip over in the race like a couple of the others did

I knew that what I learned from mouse trap racing would come in handy one day.

lmao! WOW that is ALOT of info! i will read it carefully tomorow when i start on the design! thanks a bumnch patrick!

09.16.2007, 03:33 AM

I remember building one of these in high school. I agree with what Patrick said, he could have been describing the car I built. One thing I would add is a multi ratio axle. You can wrap most of the string around your normal axle, then wrap the end thats going to unwind first around a larger section of the axle. The mouse trap arm has better leverage on the axle the closer it gets to being perpendicular to the string. You can take advantage of this increased leverage by using a longer lever extension and getting more distance, but if it doesnt have enough torque to get moving when the arm is almost parallel to the string, you wont win.
Another thing is tracking. This sounds stupid, but if its not going straight you probably wont do too well. And since you probably wont get all the angles/ measurements perfect when you build it, its a good idea to design in some adjustability. Sort of like a steering trim.

Patrick · 07:14 AM

Quote:

Originally Posted by t-maxxracer32

o ya yes patrick is it for school! it only has to go 10 feet but any more than that is extra credit

10ft! That's easy. We had to do 15m (49.2ft) with speed, so going just for distance and not speed you could easily get 60ft+ I think (as long as the surface it's on is nice and smooth, and it goes straight).

If I was going to do one again I think I would go down to my LHS or hardware store and get some 5 or 6mm diametre aluminum tube to use as the frame, axles and lever. It will be strong, light, look good and you should be able to get some that will fit standard size rc bearings.
I'd use CD's for the rear wheels and possibly the fronts (make sure you put them on the axle as straight as you can). Bigger wheels will accelerate slower, but you'll get more distance/top speed out of the same number of axle turns. Once your spring has finished powering the car the big wheels will have more momentum than little ones and will keep the car rolling for longer. CD's are a good size though.
Use a long lever like you have, but think of it like the lever is a pinion and the axle that you wrap the string around is your spur. Big pinion/lever and small spur/axle = slow take off, but high top end, and in this case distance (if you have the power to use all the gearing). Small pinion/lever and big spur/axle = Quick take off, but not much top end, and less distance. So like rc you have to find the right combo for how much power you have (spring force in this case) and what you want it to do. I like B15's idea of using a stepped axle for the string. If you get if working right I'll be like an auto 2 speed. Wind the string onto the smaller part first (second gear), then onto the bigger part (first gear).
Make sure it goes straight and smooth. How well it rolls is very important, since it doesn't have much power. I'm pretty sure that the cars that won the comp I was in, the spring finished powering the car at about half way and they rolled the second half (this was 1999 though so I could be a bit off). Mine finished powering the car at about 10m (32ft) and rolled the rest, but their's got to full speed quicker.
I'd have the end of the lever basically in line with the rear axle, but better to be slightly in front than slightly behind. Should help you get the best leverage. And if it is in front slightly then the lever shouldn't hit the axle when fully pulled back.
Now get designing, I don't want less than 50ft

Arct1k · 09.16.2007, 07:40 PM

The answer - Mamba max - 5700 - 3s lipo and a prop blade!

http://www.stampedeproject.com/Aero-Roll.html