My Physics final project (custom puller)

This is something I have been working on this week. This took me two days to build. It's finally moveable. It is my final physics project and is going to be in a competition with different groups in my class and other classes. It still needs some tinkering to the gearing to lower the temps for normal conditions as it will be in a tug-o-war competition with other groups' cars. Also, the front tires lack traction, so I will need to find something with more grip...preferably something with spikes.

                               
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And here's the tires ballooning at full throttle

                               
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Thanks guys!

mike, my plan was to make it look like a tractor! I guess I succeeded!

There is a size limit to how big the RC can be. Mine is already a little oversized in width, length is probably at its max. And ya, I really need to gear it for more torque. I tried to run it and acceleration wasn't too good, but it was FAST! Now the gearing is at 19/83, I used Tamiya gears. I am thinking of changing it to 13/83, I think Tamiya makes a 13T pinion for the Clod. Anybody know if there is lower teeth pinions by Tamiya? The 83T spur is fixed, so it can't be changed.

The wood steering piece in the front is getting weak. I am pretty sure one hard hit and it will snap. I will need to increase the bracing for it.

After I change the gearing, if the front lifts, I will add some lead weights onto it to weight it down. Not sure what else I could do, maybe move the battery forward.

Btw, the qualifying tasks are:
1. 30m in 10s.
2. Climbing slope of 30 deg up pinewood surface.
3. Pulling 5N.
4. Launching a ball to hit a target 7m away. (Still gotta work on this)

Competition:
1. 30m dash
2. Highest slope climb.
3. Tug-o-war between the RC's.
4. Hitting target 6m, 7m, and 8m.

I am estimating there will be about 10-15 groups.i

mike, the rear is a solid axle. I made the whole transmission except for the spur gear. The axle is just a solid rod of aluminum with the ends tapped for the wheels to mount on. I had plans to make the wheelie bar too, but at the moment, the front end does not lift. I guess I will have to see after I change the gearing. For the front, I am going to try a set of Tamiya rally blocks since I already have a few spare set.

Prince,
1. If I could find where to buy at least 3/4" thick lexan here, I will remake the transmission with bearings. But I am not really sure how I could put bearings in the transmission right now, the plates are only 0.120" thick I think.

2. I always thought Tamiya gears are different pitch, I have a whole bunch of pinions in the workshop that I
will try tonight.

3. 6 cell stick pack.

4. Yup, I am going to do this.

5. The servo is there as a backup. Since I made the rear axle, it does not spin true, it is not perfect. And since the event is going to be on carpet, most likely it will go to one side. The steering is there allow the truck to move in a straight line. I remember last semester, some cars went straight on concrete. But on carpet, their paths were slanted to one side. And without steering, some ran into the wall and did not qualify (0%).

It is still hard to get grasshopper wheels here. I want to use something readily available. But I will try the rally blocks first.

Just changed to Tamiya rally blocks for the front. Steering is a lot better now. Also changed the pinion to 17T from 19T. Increase the acceleration a little, but I would like more. The pinions are definitely not Kimbrough 48P, I got a few of those and they don't mesh. Maybe something with standard and metric...not too familiar with that, but I will check the LHs next week to see what they have.

python, ya it's pretty much for drag racing. Drag racing, pulling, climbing

Prince, the gear ratio in your rustler is different compared to mine because mine is a direct drive system. Meaning the only gears it have is the pinion and spur(with is directly on the axle itself). The rustler transmission has internal gears that changes the gear ratio, it is not simply the ratio of the pinion to spur itself, but have to factor in the idler, diff gears too. I don't really remember how to calculate that...but it took a while to do.

Skyline, thanks man! When I finished building this one, I had the urge to build another one because I thought of a totally different design that might work better than this one. If I have a long weekend, I think   I will make it.

Ok just destroyed the spur gear today. I will have to think of another way to fix the gear onto the axle...

Thanks. I already thought of a way to keep the gear on the axle. But this piece is going to take a while to make. Another project for next weekend.

lol the competition is on May 9th. Still a few weeks to go. I am going to be fixing it up on Thursday. Have a few plans in my head, we will see if they really work

Another update!

Qualifying is on the coming Wednesday. This is where most of the marks are given. Competition is on the coming Friday. The event is going to be broadcast live on the internet. I will post the link here in a few days if anybody is interested.

As for my car, I actually decided to make a whole new chassis because the first one was a little on the heavy side. My main goal on the new chassis is to be lightweight. I started last night and this is how far I got after a day. It's pretty much finished. This time the axle spin a lot smoother and the gear mesh is pretty close to perfect. Very happy with that. The final process will be to cut away any part of the chassis that is not needed. I am also going to be using 2/3A's for the speed and climb event to cut down on weight. For the tug-o-war, I am going to be using a 3000mah 7 cell pack to increase the weight and power. V2 is a lot more sturdier than V1, but I will be adding a little more bracing before the qualifying.

I still have to remake the catapult. I have searched on the net and have decided on a Trebuchet. Some ancient roman weapon. I will be making that on Tuesday. Hope it works lol

Here's a pic of it I just took. The chassis is made of 5mm polycarbonate, pretty strong stuff

                               
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Just noticed that I accidentally made the wheelbase perfect for 1/10 MAXX bodies

V3 is finally done after about 14 hours of work...why V3? Because V2 was destroyed by one of my group members while full throttling into a curb

Anyways, here is the link to tomorrow's competition.
http://msl.stream.yorku.ca/media ... -145d-4a72024622s4.

Oh yes...and V3...

                               
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Time for the competition is 8:30AM to 1:30PM. I think we are in GMT.
Comp is in an hour!!!

The inner plates are acrylic, the outer reinforcements are lexan. The car was very strong today, quite a few hits, but plates were fine. We won 1st in speed, 3rd in climbing. But the climbing killed my axle. I had used JBWeld 2 times for this project and at both times it failed. This time the axles were freespinning due to it's failure So basically, we had no power for tug-o-war...my favourite event! And we didn't get to participate!!!

No more JBWeld Products for me