View Full Version : Brushless Super RS4 report
I finally got my Super rs4 together and all I can say is WOW! I'm running a Warrior 9918 and Lehner 2400XL all powered by Polyquest Lipos and man this thing is fast! Too fast to drive on the street. I have the nitro 2-speed setup and when this thing shifts into 2nd it accelerates HARD! I need to find a large, smooth open space to really see how fast this thing is, not that I have any way to get an actual measurement.
Also, I want to point out that the Warrior controller works awesome. Some people have knocked this controller in this forum so I was expecting it to not be that great. It runs very smooth, no cogging at all, and when I was finished driving it was barely warm. Maybe its just on lower voltages where it has trouble, but with 14.8 volts, 6200 mah and a UBEC it runs flawlessly.
tcolesen
04-17-2005, 11:56 AM
Sounds cool! The warrior does cog with its own BEC being used on less than 6cells. You are definately best off using a UBEC. You should take a couple of pics or a video!
flnsx
04-17-2005, 09:26 PM
What Ubec are you using?
Did you disable the 9918's BEC or just keep it going per the directions?
tcolesen,
I'll post pics as soon as I figure out how, maybe a vid too.
flnsx,
Koolflight systems Ultimate bec for cars and yes I disabled the 9918's internal bec. The UBEC is a very compact, lightweight unit.
WheelNut
04-18-2005, 12:09 PM
What exactally does the UBEC do? How is it different from a regular receiver pack?
tcolesen
04-18-2005, 09:02 PM
The UBEC plugs into the main battery and regulates the main battery's power down to 6v, and that electricity is then used for the receiver. The UBEC is a very lightweight alternative to a receiver pack.
Took the car out to a brand new large black top at a school in our area and this thing is way faster than I thought it would be. I need to find some more traction somehow as it will just spin its tires in first gear and then shift into second before its gone 25 ft. If I ease on the throttle it takes off much better of course. Might have to try some of the foam tires that are out for this car. I also have no brakes. I think this is caused somehow by the 2-speed but I'm not sure why.
tcolesen
04-18-2005, 11:46 PM
Most 2-speeds have an internal clutch and one-way bearing that makes it so that when the clutch on the 2nd gear spur gear gets up to the proper RPM, it engages, and then the one-way bearing on the first gear spur gear allows first gear to spin freely with 2nd gear pulling the car. You can only use mechanical brakes with this setup. This is why electrics tend to not use 2-speed auto-shifting transmissions.
OK, that makes sense, thanks. I guess for straight high speed runs that will be ok but if I ever want to go to a track I'll need to swap in the single speed.
If your radio has three channels and channel mixing you can set up a standard servo for brakes only and the brushless ESC to be your power source. Sort of like how a nitro car is normally but you're doing it with the third channel.
Kucheg
04-19-2005, 02:30 AM
Well you could set up a mechanical brake, then use a Y harness to run the ESC and the servo off the same channel...
tcolesen
04-19-2005, 08:56 AM
If you use the mechanical brake, you would want the 9918 running forward only (its programmable).
Ok, I ran the Super RS4 again today with the same amount of voltage, 14.8, but less mah, 3100 versus 6200 since one of my packs died. The car seems to hook up much better with less weight and after about 10 mins of high speed passes up and down my street the pack temp was at 98 deg F. I was actually expecting them to be hotter but then again the car is pretty light so it may not be pulling much amps.
One question I have is what kind of temps are you guys seeing with your lipos and how hot is too hot for a lipo battery?
tcolesen
05-01-2005, 12:00 PM
98 degrees is definately fine. I think the limit for Lipos is 160 (or somewhere around there), and I personally won't let mine get above 140.
Great! I guess I'll push them a little longer and see how it goes. Thanks!
ducati777
05-02-2005, 02:46 PM
How did your pack die?
I think a small rock got between my chassis and one of my packs. I noticed the voltage going down on one of my cells and upon closer inspection I found a small dent in the cell. Just a guess though, it may have been just a bad cell.