Changing Pinions Doesn't seem to Change Headspeed... - RC Groups
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Jan 08, 2003, 01:49 PM
Registered User

Changing Pinions Doesn't seem to Change Headspeed...

What does this mean? I have one heli under construction and I'm trying to get it into aerobatic specs. Details: VoyE, hacker B40-8L, schulze 12.46e (soft timing, lower speed DIP settings), 3000mAh 10 cell, CF blades +PEK.

I'm testing at 0 pitch, pinions 15 through 19 teeth, and a glowbee tach (I have a dental mirror attached to it so i can measure headspeed while it's laying on the ground). Throttle to max (I can tell it's max because I always start with throttle slider max, and the ESC powers up with a beep-beep indicating max throttle setting). I tried to make sure that the tach wasn't also hitting the flybar in addition to the blades.

The problem: at a 15 tooth pinion, I get a headspeed of about 1600. When I switch to a 19 tooth, I get a headspeed of about 1650. What does this mean?!?

The only way I've been able to get a significantly higher headspeed is when I switch the schulze to "higher speed" DIP settings. With a 15 tooth pinion, at 40% of the throttle setting, the headspeed overspeeds, greater than 2400RPM (it shook the fins off the tail!).

I looked at the ESC specs and it's quite similar to the old schulze 45ho, and right now, the only things I haven't tried are the ESC hard timing (not sure what that will do) or get a smaller pinion for the esc high speed setting (something I've never heard from other VE owners).

Thanks in advance.
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Jan 08, 2003, 09:10 PM
Registered User
This should be kinda obvious, but...

I have a Honda CRX Si. The engine is a 1.6L and is rated for 106 hp. It can do about 110 mph on a level stretch. If I change the gearing, does this mean I can hit 220 mph?

The answer is obviously no, because at same point the engine power will equal the power lost by rolling friction and overcoming air resistance no matter what the gearing is, so even if I increase the gear ratio it won't go any faster.

Your heli situation is probably similar.

Jan 08, 2003, 10:57 PM
Registered User
I was thinking about that too, but I'm able get the headspeed way over 2400 if I set the schulze to "higher speed" via DIP switch. Zero pitch as well.

Strange. Anycase, 1600 is more than enough to get hte bird up in the air. I just won't try any areobatics with it for awhile.
Jan 09, 2003, 03:27 AM
Registered User
You should try medium timing.

Medium timing will give more current to the motor. You should be careful about overheating the motor, though.

Jan 12, 2003, 08:08 PM
Registered User

issue closed - probably a bad 18.46K ESC

somethings going on with the esc. I'm going to send it in.

Voyager1 Voyager2
Kontronic 40-6-12: 1650 (15t) 1900 (15t) <- good esc
Future 18.61: 1400 (15t) --- <- good esc
Future 18.46K 1200 (17t) 1600 (19t) <- looks like bad esc

Note that the 18.61 and 18.46k have the exact same DIP settings and very similar specs. I even increased the pinion size with absolutely NO headspeed improvement, as if the esc is maxed out on power. The 18.46k seems to be bad.