howardcano

iTrader: (37)

Do you know the number of turns on the stator, or the KV rating?

30m run line sounds like a very small track. What are typical lap times?

Running the same motor as you are using on 2s LiPo, but on 1s, will halve the free-running RPM, since RPM is proportional to voltage.

Cancun Tom

The motor is a 3000kv, 13T Basic Sport system with a 35A ESC sold by "HobbyWing". When I use the 1cell pack I have to turn off the voltage protection in the ESC to get throttle.

Yes the track is small. You can view it on youTube at this link:
https://www.youtube.com/watch?v=7cVVsj_7GjM although we were running touring cars on that day. I was turning 5.5 sec laps using the exact same motor/esc that I plan to run in my pan car.
Thanks so much for your reply.

howardcano

iTrader: (37)

Okay, (3000 RPM/V) * (4.2V) = 12600 RPM no load.

If we were to gear so the motor runs, on average, at its horsepower peak (which is half of the free-running RPM) we would be shooting for:

12600 RPM / 2 = 6300 RPM or

(6300 revs / minute) * ( 1 minute / 60 seconds) = 105 revs / second


Average speed on the track is 30 meters / 5.5 seconds = 5.45 m / sec

so we want a rollout of

(5.45 m / sec) * (sec / 105 rev) = 0.0519 m / rev

or, in mm, 51.9 mm / rev


Tire diameter = 2.43 inches or

(2.43 inches) * (25.4 mm / inch) = 61.7 mm

and the circumference is

3.14 X 61.7 mm = 193.7 mm


The gear ratio to achieve the desired rollout is

193.7 mm / 51.9 mm = 3.73


To be safe, I'd start out at about 4.5 and adjust from there depending on motor temperature.

A rear-drive pan car on caps with a 13T motor on that size track might be limited by wheel spin! You may find your lap times are better, and the car is easier to drive, by setting your throttle EPA to less than 100% (to limit torque). Then use a little more gear if necessary to get top end back.

espresso1967

iTrader: (18)

I'd like to show up on Sunday and check out what kits are being run for WGT and type of esc's, motors and batteries being used.

What time would be good to show up without being in someone's way while asking questions or just looking?

Cancun Tom

Howard,

Thanks so much for your help on this. I really appreciate the time you took to provide a great technical explanation that taught me how to make this calculation myself in the future.
Cancun Tom

howardcano

iTrader: (37)

I'm glad to help.

How would you guys feel about having another racer in your group? Maybe sometime in January?

Cancun Tom

Howard,
Yes that would be great. We race outside all year long. January is cooler so it's much more comfortable. I can provide you with either a pan car and or a touring car, batteries, charger, tires, etc. I'll be the team owner and you can be the team driver. I'll send you my contact info via PM later today.

avs

iTrader: (2)

any friday eve or saturday afternoon is calm and Sean would have time to show whats new. ( i don't know who else is running a genx)

last sunday was a regular club race day and would have been a good time to drop by. series race sundays are pretty busy, there is a good turnout with maybe 15 heats to get thru. (track opens at 8, racing starts at 10, generally over by 5 and the track closes at 6)

Cancun Tom

Could someone give me a step by step description on how to set the camber on my CRC GenX 10 LE ?

Thanks in advance.

vafactor

iTrader: (6)

camber settings are super easy on the CRC front end. It's a simple matter of turning the upper arms' pillow ball in (clockwise) to increase camber or to back the pillow ball out (counterclockwise) to decrease camber. Some wheels have holes or spoke spacings that will allow you to stick a long allen wrench in thru the wheel to make the camber adjustment while the wheels are on the car. But some other wheels don't have openings that line up with the allen in the pillow ball, so with those style wheels it can be necessary to remove the front wheel in order to access the allen recess in the end of the pillow ball. Most guys run their camber at around 1/2 to 1 degree (top of the front tire leaning slightly in towards the car's centerline). If you don't have a gage, one is not really necessary. The wear on the front tires will tell you what the car wants. Basically, the goal should be to adjust the camber settings so that the front tires wear flat accross and they don't cone, which should be a good setting. If the inner edge of the front tire tends to wear faster than the outer edge, then that wheel is leaned in too much (has too much camber). And if the outer edge becomes a smaller diameter than the inner edge.......then you need to add more camber. It's really very simple.

Cancun Tom

VFFACTOR,

Thanks worked perfectly. Didn't see the access to the pillow ball.

Codfather

iTrader: (14)

Does anyone have a good foam bumper recommendation? The bumper I'm running doesnt extend out the sides far enough for my liking. Looking back at SG1's pictures the bumper seems to extend just shy of the outer wheels. Just carve my own custom bumper?

Still Bill

iTrader: (16)

A Hudy 5/64" ball-ended Allen wrench will get into that pillow ball at odd angles. Saves you from having to remove and reinstall the front wheels for those camber adjustments. Quick!

Bill

Still Bill

iTrader: (16)

Are we talking a 1S or 2S setup? Makes a difference in how much weight is involved.

How is your existing foam bumper currently connected to the graphite bumper? Besides the body posts, what screws are in place (if any)? And how far does the foam extend in front of the graphite bumper?

Bill

BullFrog

iTrader: (4)

I use a Kydex bumper only got rid of the foam with no problems.