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e-JR Voyager E > pinion teeth with hacker 12S
 
 
luc
Heliman
Location: France

Hi
still trying to eliminate the tail wobble.
I have 1480 rpm now with the hacker 12S and 15T on 3 li-po. Only 14A draw.
Should I go to 16 or 17 T ?? What would be the additional amp draw in each case? (2A per tooth)?
01-18-2004 Over year old.
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Ralphw
Key Veteran
Location: Spring, TX

I would certainly try the larger pinions. A 16t should run at 1801 rpm (no load) and a 17t should provide 1913 (again no load on the motor). You said you're only getting 1480 on the 15t pinion, which seems a bit low. The "no load" rpm should be around 1688 for the 12S with a 15t pinion, so a 200+ rpm drop seems a little excessive. What throttle curve do you run and are you getting a good charge on the battery (what battery voltage fresh off the charger?). You might also check belt tension as I found this to contribute greatly to added mechanical drag (it really showed up with the Astro motor, before I replaced it). Hope that helps.

Ralph W.
"Life's Short, Fly Fast"
01-18-2004 Over year old.
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tailspin
Heliman
Location: Kent Washington

A 16 tooth should get rid of the wobble without overloading the motor. The 12S was meant for a Corona, but should work on the VE. It's not going to give you any super performance though. My VE works great with the Astro 020 using a 15 tooth pinion with a 3 point throttle curve of 0-90-90. My pitch settings are -2 at bottom stick, +6 at mid stick, and +12 at high stick. You might just try decreasing your pitch a little and increasing your throttle curve?

What kind of throttle and pitch settings are you using?
01-18-2004 Over year old.
 
 
luc
Heliman
Location: France

my throttle curve (T9CAP) is 0-100-100-100-100.
and pitch 3-3-5.5-6.5-10
Interesting the belt tension issue: do you mean it is too tight?
Also I don't see how you come to these rpm.
3 li-po gives 10V, no more, which would mean 1580 rpm (I get 1480 under load).
So I guess I should go straight to 17T, to get around 1600 rpm...
On the other end, my VE is very light thx to lipo, at 47.5 oz (1350g)
01-19-2004 Over year old.
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Ralphw
Key Veteran
Location: Spring, TX

3 LiPO's should be giving you more than 10v. LiPO's are 3.7v per cell, so a 3s pack is 3.7 x 3 which equals 11.1v. Right off the charger they will carry a "surface charge" that will put them a good bit higher than that.

Regarding the belt tension, yes I meant too tight. I had a tendency to run mine to tight in the beginning and when it was suggested that I loosen it a bit, it made a noticeable improvement (mostly a heat issue for me, but there was an RPM increase as well).

Last but not least, I would recommend a pitch curve with a little less pitch at the bottom. My "Normal" curve works out to -2/-1/ 0/ 6/12. I don't typically fly in "Normal" ( I just use it to spool up) and my Idle Up curve is symmetrical with -12 on the bottom and +12 on top, 0 at mid stick.

Good Luck.

Ralph W.
"Life's Short, Fly Fast"
01-19-2004 Over year old.
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luc
Heliman
Location: France

Thx for the info on the belt, I will decrease the tightness.
For the li-po, sorry to tell you that you don't know the subject (nominal voltage is not the same than under load, nominal voltage for nicads are 1.2V and 10 nicads don't deliver 12V under load)... 3 li-po, under load give no more than 10V, which is a bit less than 10 nicads and that's the reason for the little rpm I get by comparaison with 10 nicads. Of course, on the other side, I am lighter, which helps for lifting the heli, but maybe not that much for its stability..
01-19-2004 Over year old.
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Ralphw
Key Veteran
Location: Spring, TX

Just for clarification, please note my earlier post which stated "No Load" I am aware that there is a difference between No Load and Loaded values. Also, for what it's worth my C40 comes out VERY close to the calculated values but I've taken the time to minimize all mechanical factors relating to load on the motor...belt tension, ball bearings where possible, good lubriction, gear lash etc, etc. Just my two cents and I'll leave it to you now. Good Luck.

Ralph W.
"Life's Short, Fly Fast"
01-19-2004 Over year old.
HOMEPAGE  
 
 
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e-JR Voyager E > pinion teeth with hacker 12S
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