6 - 12 inches off of ground only

actually, I think the math says the 9/96 is actually a hair slower.

10/100 = 10:1 (ten pinion turns to 1 main)
9/96 = 10.666667:1 (little more than 10 turns to get one main revolution)

So in the end, the 9/96 will take more RPM/V to get the rotor up to the same headspeed.

Elton

IT FLYS!!!!! I switched back to 9/96, and the heli flys now. That is amazing that the 9/100 made such a big difference. Wow. I feel like Jessica Simpson with my lack of gear ratio knowledge. MY HELI FLYS... HOORAY!!!

Yeah, with the 9/100, you're talking a ratio of 11.1111:1 for that combo (the pinion must turn eleven times before the main turns ONCE)

As I said earlier, now that you have 9/96, you're at a hair over 10 and a half pinion turns to get one main rev.

if it 'just barely flys' or doesn't seem to have quite as much ZIP, and the battery and motor aren't TOO warm after the flight (given you're not draining them all the way until you can barely stay hovering in GE) try moving up to the 10/100 combo.

That will give you a ratio of 10:1 (10 turns to get one main revolution, if you are still following from my previous example)

The motor will now be under more load though, thus drawing more amps, but you'll have more power during flight, which means better ascent and slightly higher head speeds.

If you find it climbs to much though, then go back to the 9/96 combo.

From what I understand, the 310 is a pretty strong motor for it's class, so it should be able to handle the load demand without going nuts on efficiency (drawing too many amps and shortening flight times and heating up your battery a bit more)

If you're aching for real climb power, then go all the way to 10/96

10/96 = 9.6:1 ( less than ten pinion turns to turn one rev on main)

This puts ALOT more load on the motor, so flight times should be shorter, but as I said, the 310 might be able to handle it. You'll know right away if it can't, the same effect will happen and the heli won't get out of GE.

(but I think it will, and will have loads of climb out power too boot)

Rotor Up!

Elton

[rdn1153]

I'd say you still have a set-up problem that you are trying to mask by changing your gear ratio. A 310 using a 9/96 ratio should have no problems flying at all, especially if you are using a 9C pack which should be pretty hot for it.

I get 20 mins flying time with a 310, 9/96 gearing, stock blades on 2C 1020 Kokams.

You meant 8 cell, right? (based on his sig? or did I miss something?)

Also, This got me thinking, and I went back to the initial post, and saw the direct drive tail, and the pro tail motor.

Hogster, Reflex and I have just started discussing this in his (hogsters) thread about the tail motor having a built in advancement for timing as the brushes wear; now, running it backwards becomes a horribly inefficient draw once you reverse polarity, and to add to that, it's running at higher draw rates because of the direct drive.

Could it be possible that the increased tail motor draw while flying and thus, simultaneous to main motor draw, limit his overall motor draw current such that the motor can't do it's job?

Especially if the connectors are standard BEC connectors...

Just a thought... any opinions on it?

Elton

[MajorMattMason]

I think you guys are right, there's still something else that was wrong. Four teeth on the main gear shouldn't make such a big difference. He was getting in the air fine before.

I wanted to say slipping pinion or the dd tail was sucking too much juice or something. [img]/ubbthreads/images/graemlins/confused.gif[/img]

I'm going to try the 10/100 setup like you guys reccommended.

Does anybody have a say about the lightend main gear versus the flywheel main gear? I'm talking about the two different main gears on the helihobby website.

[rdn1153]

[ QUOTE ]
You meant 8 cell, right? (based on his sig? or did I miss something?)

[/ QUOTE ]

I read the wrong closing, it's your's that has the 9x750 NiMh.

I ordered the 8 tooth and 10 tooth chromed pinions so that I can play with the gear ratios.

10 teeth is definatly better for the 100 tooth main gear?
How about if I did 11 teeth? Would 11 teeth blow out my 310 motor?

Here ya go.

I threw this spreadsheet together really fast; it outlines the different ratios for each pinion/main combo.

Then I sorted the list, based on lowest gearing (highest ratio number) to highest gearing (lowest ratio)

eg, 8/110 yields the lowest gearing, meaning many MANY turns of the motor to generate one rev on the main.

Assuming a constant target rotorhead speed, The closer to the top of the table, the more spins and less torque required to get the rotor up to speed. (there comes a point though that you can't feed enough volts into the motor to spin it fast enough without burning the motor out)

The nearer to the bottom, the more torque required but less revs. (there comes a point where the motor can't put enough torque out though, and you don't hit the target RPM)

Table: (also attached for those that can't see the link)