Slow down

LowClassCC · #16 10-27-2009, 07:29 PM

i have a 4 year old son that i am slowly teaching to drive rc cars. the car i choose for him was a vintage rc10L due to the fact that the cars are very simply constructed and easy to fix. the car us running foam tires of an unknown hardness. the body is a truck that offers pretty much zero down force. and its driven on a standard unprepared blacktop parking lot.

so you can most likely imagine how uncontrollable the car was using a basic 27 turn stock motor. no less with a 4 year old at the controls.

i tried a 5 cell nicd. i tried gearing down. but that did not help all that much. gearing down may have actually hurt since the biggest problem was spinning out during takeoff. and teaching throttle control to a 4 year old is not likely going to happen.

well gearing down did slow down the top speed but the torque still caused that car to spin as i had stated. i dropped in a vintage speed controller. one that has the 2 dials that you can adjust with a screwdriver. i adjusted that down and that really helped. but that alone did not give the throttle a very smooth feel but it did help. my next step was to drop a 65 turn crawler motor in it. i readjusted the speed controller to give it a little more but still not full power. the car is now running a 6 cell 1800 nicd stick pack and runs great. the speed has been drastically reduced to make it drivable yet it still maintains full throttle control. and lets not forget the fact that it would take someone with real skill to spin the car out now.

65t crawler motor
vintage adjustable speed controller
geared down
6 cell battery

these changes have made it possible for my son to have an rc car that he can drive and do more with that don't involve donuts. it really brightened his thoughts of rc since he can now drive the car.

and i almost forgot. the car now gets around 35-45 mins with the 1800mah 7.2v 6 cell nicd pack. just think how long a 5000mah lipo pack would last lol

trackman · #17 10-27-2009, 08:41 PM

Thanks LC/CC for your idea,
What would you say your top speed is?

I was considering a 35Turn by hpi racing,,,
http://www3.towerhobbies.com/cgi-bin...?&I=LXWYE2&P=7

That motor is a direct replace for this 4X4 buggy by HPI
http://www3.towerhobbies.com/cgi-bin...?&I=LXVZB2&P=V

Some rc reviews state that buggy does about 13 mph stock, but that is with a stock 65T spur and a 24T pinion.

If I have a 90spur and 15 pinion I may need to get a turtle shell for it

I have to agree I think a good quality stock motor escessively geared down will be to much wheel spin Unless I went with the Streak ESC with spin liminator, That ESC also has 4-10 cell capable .

Maybe if I went with the Streak esc I could run some 5 cell packs ,35T motor , Mod gearing and when some Jack ass comes along talking about how slow those cars are I could put a little wager on it and sneak TWO 5 cell packs in there and blow'em away

trackman · #18 10-27-2009, 10:07 PM

My Stock esc has a 20 turn limit 6/7 cell, The Duratrax streak has a 12 turn limit 4 /10 cell limit.

Now My question is , If I were to go with a 35, 45 or 55 turn motor on an ESC as stated above will there be any limitation restrictions for the ESCs in the opposite direction as if running a lower turn motor specs limit?

Stock 27 turn is usually the norm, but are way higher turns such as 35, 45, 55 and 65 compatable with the ESC's such as the Streak with a 12 turn limit?

LowClassCC · #19 10-27-2009, 10:31 PM

12 ad 20 considered modified motors. they are faster and run hotter than say a 27 turn stock. a 35 turn in turn is a slower motor than your 27 turn.

basically it the esc has a limit of 20 turns don't put a 12 turn motor on it because it can not handle it. if the esc has a limit of 12 turn motors don't run a 10 turn with it.

as far as running colder and slower motors like a 27 turn, 35 turn, 55 turn or 65 turn you are good to go with what you have.

as far as how fast my rc10l is i'm not sure. its still more than twice as fast as the walmart toy rc cars the other kids in the neighborhood have. but slow enough to get laughed off an rc track trying to run against the stock guys. yet to the kiddo's around here it's lightening fast! lol

TOM MAR · #20 10-28-2009, 12:30 AM

Do you know if you can use a receiver pack with your speed control ?

trackman · #21 10-28-2009, 07:44 AM

Quote:

Originally Posted by TOM MAR

Do you know if you can use a receiver pack with your speed control ?

One did'nt come with the system. I'm guessing probably not due to the primary battery connects to the speed control then the speed control sends a certain amount of voltage to the receiver to operate the steering servo and I would guess the reciever to recieve the radio signal.

But the receiver does have a battery pack connection point, Which I think most 2 channel receivers have.

Why; What's the idea behind that thought?

martian 710 · #22 10-28-2009, 10:24 AM

The Sprint speed control is rated for 5-7 cells. So a 5 cell should work for sure. When my daughter first started racing I had a cheap Duratrax speed control in he car that was rated for 6-7 cells and it worked fine on 4 cells. I don't think I did anything to bypass the BEC.

trackman · #23 10-28-2009, 12:56 PM

Quote:

Originally Posted by martian 710

The Sprint speed control is rated for 5-7 cells. So a 5 cell should work for sure. When my daughter first started racing I had a cheap Duratrax speed control in he car that was rated for 6-7 cells and it worked fine on 4 cells. I don't think I did anything to bypass the BEC.

Wow, thanks for that info on the ESC of 5 to 7 cells...
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXAMN7

The manual for the Evader St always said requires 6/7 cell so I went from there,
But then again it has a 20 turn limit and I have ran 17 turns with 7 cells constatntly for many packs and it keeps on running....
I think they may have giving this ESC a big ol' safety net far as the specs.

TOM MAR · #24 10-28-2009, 01:57 PM

Quote:

Originally Posted by trackman

One did'nt come with the system. I'm guessing probably not due to the primary battery connects to the speed control then the speed control sends a certain amount of voltage to the receiver to operate the steering servo and I would guess the reciever to recieve the radio signal.

But the receiver does have a battery pack connection point, Which I think most 2 channel receivers have.

Why; What's the idea behind that thought?

With some sc's you could plug a 4 or 5 cell receiver pack directly into the receiver, allowing you to run very low voltage to run the motor. ( we did this in 4 cell oval) I was wondering if "a receiver pack pluged in to the receiver & a 2 or 3 cell pack hooked to the sc" would work & do what you were asking ?
I Have not tried this,Just wondering if anyone knows if this would work with this system.

If you try this make sure you DO NOT connect more than a 4 cell pack to the receiver until you have the specs on how much voltage your receiver & servo is rated at.

DJ1978 · #25 11-03-2009, 03:54 PM

Simple way is to tape a foam stop to the handle so the throttle can not be pulled as far.
That way you can just set the vehicles up properly and limit the throttle travel.
Less cells would work.. but then you dedicate all packs you change to the lower voltage.
If you just limit trigger travel, you can use the same vehicles for inexperienced drivers and take the stops off for more experienced groups.