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Old Oct 04, 2005, 10:50 AM
wac
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Joined Jun 2005
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does a bigger pinion draw more amps ?

So i burned out my hacker E3 49kv 12a-20a (demaginatized) and im woundering since im using a 10 tooth pinion on my Hummingbird 3d pro with a electron 12A - 18a peek esc(from century) could that be the reason why im drawing to many amps.. and if i went down to a 8 tooth pinion would that draw less amps ?
take care all and God speed
wac
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Old Oct 04, 2005, 11:34 AM
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Vince Herman's Avatar
United States, OH, Strongsville
Joined Nov 2000
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Yes, all else staying the same, a bigger pinion will draw more curent than a smaller pinion.
Motor temp should be something that you monitor. If the motor is getting that hot (too hot to touch for a few seconds after a flight) then it is an indication that something is wrong. You are wasting power heating up the batteries and the motor (and also taking things outside of the survivable temp range).
A watt meter is helpful for quantifying current draw.
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Old Oct 04, 2005, 12:01 PM
Rufus T. Firefly
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Massachusetts, USA
Joined May 2004
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What will a smaller pinion do to the headspeed? I have a similar problem with my himax 4100 and my fp hummer. I'm currently using a 10 tooth pinion with like 90's, and my motor gets extremely hot after about 8-9 minutes. If I switch to an 8 tooth pinion, will I get more headspeed or less?
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Old Oct 04, 2005, 12:23 PM
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Old Oct 04, 2005, 12:59 PM
wac
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I confused about something... using my hacker e3 49kv w/10tooth p i would set my max throttle to about 85% to controal head speed (2600 + or - ). But i used an 8 tooth pinion i would have to increase my max throttle to 90-100% to get the same head speed..

Is this correct ?
let me know
wac
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Old Oct 04, 2005, 01:25 PM
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Basingstoke Hampshire UK
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The problem with running 85% is that the ESC is doing a lot of switching. You need the corect pinion for the motor.If the motor is hotter then coffee cup temp then something is wrong. Go to a lower pinion. You will be able to open the throttle up a bit more and the ESC will swich less. You motor will thank you for it.
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Old Oct 04, 2005, 01:26 PM
Rufus T. Firefly
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Massachusetts, USA
Joined May 2004
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So, a smaller pinion = less headspeed, correct? So, in order to get the same headpeed I was getting, and have a cooler running motor,I would have to switch to a smaller pinion, and a bigger motor? The 2015-4100 kv himax is plenty powerful for my setup, but if I switch to an 8 or 9 tooth pinion, I may not have the neccessary headspeed to leave the ground? This IS confusing. Can someone please tell me exactly what motor and pinion size I should use to stay reasonably cool using fp like 90 blades?
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Old Oct 04, 2005, 01:36 PM
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Quote:
Originally Posted by Lightnin' Bug
So, a smaller pinion = less headspeed, correct? So, in order to get the same headpeed I was getting, and have a cooler running motor,I would have to switch to a smaller pinion, and a bigger motor? The 2015-4100 kv himax is plenty powerful for my setup, but if I switch to an 8 or 9 tooth pinion, I may not have the neccessary headspeed to leave the ground? This IS confusing. Can someone please tell me exactly what motor and pinion size I should use to stay reasonably cool using fp like 90 blades?
Your motor should be good enough. What blades are you using? What you need to do is gear it so that you are getting your desired headspead with about 95% throttle. That way your ESC is not working so hard. The blades make a difference. The SAB carbons for instance create more lift at the expense of power. On the other hand the woodies create less lift and are easer to drive. Its all a ballance.
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Old Oct 04, 2005, 02:10 PM
Rufus T. Firefly
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Massachusetts, USA
Joined May 2004
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I'm using like 90 fixed pitch wooden blades on a hummingbird v2. My heli is very heavy for a hummingbird, as I have the g 10 frame, Apogee 3 cell 1570 mh, brushless motors for main and tail. Don't know what kind of rpm's I'm getting, using the 10 tooth pinion, but I can guarantee it's pretty high for a fixed pitch copter. I would like to get a slightly more powerful motor, and go with a smaller pinion size, but I'm afraid the phoenix 10 esc won't be able to handle it. Any suggestions?
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Old Oct 04, 2005, 02:42 PM
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United States, PA, Lake Wynonah
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Lightnin, thats one heavy heli. Try dropping the pinion to a 9 tooth and see how hot things get. If it's still too hot go to an 8 and see.
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Old Oct 04, 2005, 03:25 PM
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Orlando, FL
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For my FP hummingbird im using an 8 tooth pinion, a Feiago main motor, and Like90 blades. It's working well......good head speed and motor does not get that hot.
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Old Oct 04, 2005, 05:03 PM
Rufus T. Firefly
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Massachusetts, USA
Joined May 2004
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Thanks guys, I'll be dropping a pinion size and see if that helps. The reason I have such a big battery on this bird is because I was using a 2 cell TP 1320 mh but it didn't have enough power to keep up. I could probably get twenty minutes of flight time with the apogee 3 cell, but I have to stop and let the motor cool down. It does the job ok, but the himax 4100 does get red hot, probably because of the weight. It seems like there's always a trade off. I've been reading the thread about the kyosho m-24 blades, and I think I'll give them a try also. By the way, Skeppley, I really enjoyed reading your thread about the x-400 I'm thinking of getting one. Torn between that and t-rex. Thanks again, Dave
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Old Oct 04, 2005, 09:06 PM
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Quote:
Originally Posted by Pure Platinum03
For my FP hummingbird im using an 8 tooth pinion, a Feiago main motor, and Like90 blades. It's working well......good head speed and motor does not get that hot.
I have the same setup on my FP Aerohawk, with 3S LiPo. Dropping to an 8-tooth pinion really helped reduce the motor temp. No problems leaving the ground however it's climb rate was slightly reduced from that of the 9T pinion. I'll also note that the maximum headspeed (holding the heli) measured nearly the same with both pinions. I never compared AMP draw...would have been interesting.
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Old Oct 05, 2005, 10:28 AM
wac
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Joined Jun 2005
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I was woundering,, if im not in an idel up mode,, and i crank the throttle and collective up,, is that a situation that would cause the motor to draw more amps??
and i was using a 10 tooth pinion with my hacker e3 49kv.. is that far to big of a pinion and if so would an 8 tooth be better ?

take care
wac
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