Project Viper

Originally Posted by What's_nitro?

Nice find. That is exactly what I was thinking of. But daaaaamm- $26?

Its pretty darn good for a "custom" size gear. I've bought 4 gears from this place and they are all high quality. I never thought the delrin gear would hold up to the 6.5hp I have in my car, but its doing well after 7-8 high speed passes.

Originally Posted by What's_nitro?

Nice find. That is exactly what I was thinking of. But daaaaamm- $26?

Plus, checkout how much a 51t steel gear ring from OFNA costs!!! $26!!!:


http://www3.towerhobbies.com/cgi-bin...?&I=LXBM52&P=7

[What's_nitro?]

How's this?

Differential Ratio: 3.142857142857143
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 40
Pinion Tooth Count: 30
Total Voltage: 22.2
Motor KV: 2200
Tire Diameter (inches): 4
Tire Ballooning (inches): 0.1
Motor Current Draw: 100
Motor coil Ω: 0.006
Spur/Pinion Ratio: 1.33 : 1
Total Ratio: 4.19048 : 1
Tire Circumference (inches): 13.19 inches (335.15 mm)
Total Motor Speed: 47520 RPM
Vehicle Speed: 141.69 mph (227.61 km/h)
Estimated Adjusted Speed: 112 mph (180 km/h) - 21% loss
Effective KV Value: 2140.54
KT constant: 0.61 oz-in/A
Motor Torque: 0.32 ft-lbs
Final Torque: 1.34 ft-lbs
Final Power: 2220 watts (3 HP)

I think that should work

[What's_nitro?]

Eeek! My kit came with that one, but I bought the plastic 51T from Mike.

Another problem now is; where can I get a steel 30T M1 pinion? Sdp-si only has them in 303 SS which is really soft, isn't it? I'd be comfortable if it said it was 304, that stuff is mean (it killed my rotary tool).

Originally Posted by What's_nitro?

Eeek! My kit came with that one, but I bought the plastic 51T from Mike.

Another problem now is; where can I get a steel 30T M1 pinion? Sdp-si only has them in 303 SS which is really soft, isn't it? I'd be comfortable if it said it was 304, that stuff is mean (it killed my rotary tool).

They have 32-36 tooth mod 1 in carbon steel with 8mm bore and 6mm face.

[bl-is-future]

wow what a car. It took me a while to read this whole thread, looks good though.

[What's_nitro?]

So I got the gears- those acetal w/brass hub and set screw ones. A 30T (pinion) and a 40T (spur). They fit great, and it's REALLY fast- as far as I can tell on my street. Only problem is I can barely start from a standstill. It cogs horribly with the tall gearing. You (B4maz) said you weren't seeing any cogging with your setup, which is also what I would expect with your gearing choices :P.

Do you think it could be the controller? The Sentilon may not perform well under high starting loads, agan being an air controller it wouldn't have to. Would more capacitors on the ESC help this at all or is it most likely a firmware issue? Should I discontinue running it until I get a MMM??? I know they start very smooth and the slow speed control is excellent.

Originally Posted by What's_nitro?

So I got the gears- those acetal w/brass hub and set screw ones. A 30T (pinion) and a 40T (spur). They fit great, and it's REALLY fast- as far as I can tell on my street. Only problem is I can barely start from a standstill. It cogs horribly with the tall gearing. You (B4maz) said you weren't seeing any cogging with your setup, which is also what I would expect with your gearing choices :P.

Do you think it could be the controller? The Sentilon may not perform well under high starting loads, agan being an air controller it wouldn't have to. Would more capacitors on the ESC help this at all or is it most likely a firmware issue? Should I discontinue running it until I get a MMM??? I know they start very smooth and the slow speed control is excellent.

I wish I knew more about the Sentilon controller. I didn't think cogging would be that bad that you couldn't even get the car moving. It sounds like a controller issue because I know people that run the same motor/batteries but use a Castle controller and don't get cogging that bad. I'm sure the MMM will be much better. I don't think capacitors will help much with cogging. I would definitely upgrade the firmware to the newest version. They might have fixed the problem with firmware.

[TDC57]

What a cool project, you should race Lic when he gets his 4 Tec running..

[What's_nitro?]

B4maz: I don't think the Sentilons have upgradable firmware..... I want to buy a new ESC anyways because I hate the mechanical brakes. I put the second disc back on and they still fade to nothing after a few stops. There's just too much heat present. I'm thinking HV110 over the MMM, should I ever want to go FASTER.

TDC57: When, and IF. So long as the course has no turns, I think it's in the bag.

Have you tried to use high timing on the speed controller? That might help with the cogging.

[What's_nitro?]

No, I will try that. It was so excessive that I doubt it would be readily driveable after just a timing change.

[What's_nitro?]

Well I still don't have a controller, but I have braces!





Just made them last night. It's some 1/4" aluminum tube with the ends flattened/drilled/sanded. Those are my (hopefully) uber traction tires. They are Proline 1/8 buggy MOABs.

[What's_nitro?]

Wow. It's been a while. Oh wait- we're in a recession and I have no liquid assets! That's why!

Anyhow, I ordered up some 12"x24"x0.08" (2mm) 7075-T6 aluminum plate a couple weeks ago. The other day I got around to cutting it up. Here's what it looks like now:



I also ordered a 12"x48"x0.025" piece of polycarbonate to make the sides and the internal support structures. It came today, so hopefully next week I will have time to cut it up a bit. I'm going for the "speed wedge" look, with a twist- I'm going to design a venturi into the top so that it will create a vacuum inside the body and (hopefully) help stick the car to the road.