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Old Mar 26, 2012, 03:02 PM
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Mike_Then's Avatar
United States, NC, Garner
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Question
Motor temperatues in scale fuselages

A question about motor temperatures for electric setups inside scale fuselages. I flew my AS-550 a few weekends ago and noticed the motor came down pretty hot. So hot that I could barely touch it. The ESC heatsink was quite warm but I wouldn't go so far as to call it hot. The battery was barely warm. The day was in the high 70's so it's not like it was really hot outside.

I don't think this is a stress issue but more of a lack of cooling issue. I thought about mounting some small computer fans on the inside of the fuse to get some air over the motor and ESC. I could run them off the regulator since the battery is 6s... or I could possibly find some 24V computer fans... hmmm...

Anyway, what are your electric motor temps for scale birds and what did you do to solve any issues? Thank you!
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Old Mar 28, 2012, 08:30 PM
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I don't think the computer fans blow enough air to make a difference. I have a couple I was thinking of puting in my Coast Guard heli. I am thinking about one of those ducted fan motors with a seperate battery pack.
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Old Mar 29, 2012, 10:58 AM
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adding more weight causes the electronics to pull more Amps which turn into heat
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Old Mar 29, 2012, 11:38 AM
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I have seen some installations that did use the small computer fans and a cooling vent to draw in cooler air, and they claimed it worked well.

I may try it on my next electric scale subject.
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Old Mar 29, 2012, 11:41 AM
kin
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One other factor is the thottle curve when you are hovering orflying ?? it is direct effect how many Amper in your usually flying . if you are use normal thottle curve in hovering. i think is 60 % power it mean the amper is get in high ! but if you let (set) the thottle curve in full or 90% in all the flying time . it mean you are setting in a (high volt-low amper status ) , the power set (esc and motor and battery) also in a comfortable situation . you can get the cool setting . I also use 90% power curve when i flying any different flight condition , just control the pitch ! the head speed is control by the gear ratio only .! so how to set the head speed is very important ! i fly my 800 size models and 8s lipo , i only use a Kontronik 65 A esc is more than enough and a little bit warm only (35-40 degree in summer time ) !
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Old Mar 29, 2012, 03:54 PM
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Mike_Then's Avatar
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Thanks for the replies everyone. I'm flying the stock Align motor/ESC that came with the 600e kit. 6s 5000 mAh 45C battery. I dropped the pinion one tooth - I believe it's a 13T pinion - which is the lowest I could go with the 6mm shaft on that motor. My throttle curve is a straight 80% throttle in idle up. Anything less and I get vibrations.

I never put an amp meter on it but I guess I need to. I've got a pretty shallow pitch curve and very low throws so I'm certainly not banging on the collective for scale flight.

I found a 24V 80mm computer fan that could run right off the battery pack. It's fairly lightweight and the heli has power to spare so the weight gain should be negligible. I could experiment with the position of the fan to see if there's any gain in cooling or not. I've got nothing to lose at this point, other than not being able to fly it as the weather gets hotter. I wish I could find a smaller 24V fan so I could run several of them. The smallest I found so far is 80mm.

**edit** Found a 60mm Sunon 24V fan for $7.38 from Allied Electronics. Google is a wonderful thing. Will have to keep digging to see what else I can find.
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Old Mar 30, 2012, 12:01 AM
kin
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I think no put the fan in your fuselage , it is a extra weight and power lost ! the good idea is change the stock motor , Align stock motor we never use it . it is a rice cooker , so if you use a fan to make the motor cool . it mean you take a extra power to let other power run away .(heat is a power ) it is not good idea ! change a motor , we have using this motor have very good power and high efficiency . but i am not hard sell here , just let you know you have choice !
http://www.smartmodel.com.hk/product...9&image=image1
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Old Mar 31, 2012, 04:25 AM
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I am still thinking of a small edf motor for my Hughes 500. They are only a few bucks. A brushed one could work straight off main power. It would be reversed in the hole in the back of the fuselage. Hmmm..
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Old Apr 02, 2012, 09:25 AM
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Quote:
Originally Posted by Greybird View Post
I am still thinking of a small edf motor for my Hughes 500. They are only a few bucks. A brushed one could work straight off main power. It would be reversed in the hole in the back of the fuselage. Hmmm..
Are you thinking of attaching a fan to the motor for cooling, or am I misunderstanding? I'm still kicking around the fan idea, as the flying season is upon us and I don't want my AS-550 grounded. I'm thinking of whether the trouble of mounting fans (cheaper) is better than simply buying a new motor (easier, but more expensive).
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Old Apr 03, 2012, 07:32 AM
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I did a little brainstorming this morning and was thinking of the simplest way to do this. I'm thinking of removing the top windows to allow for more cooling air to enter the fuselage, both from the rotor wash and forward flight. I would then mount 1-2 of these fans I'm thinking of on the bottom of the fuse (inside, of course) to help pull the air out of the fuse. I'll have to measure and see what will fit. I'm thinking of two of these fans.

**edit** Ooooh here are a few more fans. This one has a slightly higher airflow (for slightly more amps) and this one is 40mm which may better fit the fuselage. Hmmm, a couple of those on the bottom of the fuse and tied into the main battery just might do the trick.
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Last edited by Mike_Then; Apr 03, 2012 at 07:43 AM. Reason: Found more fans
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Old Apr 03, 2012, 05:32 PM
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The key to motor survival in a fuse is to ensure that air in the fuse gets changed regularly. A small fan can work wonders actually. On my Approach Cobra I have a small fan pulling air in from a hole behind the dummy gun. The air has to leave from around the swash plate or through the dummy engine. In either case, it can't just sit around the motor getting recirculated and getting hotter and hotter.
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Old Apr 03, 2012, 08:35 PM
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Quote:
Originally Posted by teamdavey View Post
The key to motor survival in a fuse is to ensure that air in the fuse gets changed regularly. A small fan can work wonders actually. On my Approach Cobra I have a small fan pulling air in from a hole behind the dummy gun. The air has to leave from around the swash plate or through the dummy engine. In either case, it can't just sit around the motor getting recirculated and getting hotter and hotter.
That's what I'm hoping these fans will do. I was going to pop off one of the top windows to let in some cooling air but I think I can mount a 40mm fan in the air intake opening at the top of the fuse. I'll then mount two 60mm fans in the opening at the bottom of the fuse. These three fans together should draw less than an amp, which won't be noticable as far as flight times are concerned.
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Old Apr 04, 2012, 07:15 AM
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I ordered three fans last night from Allied Electronics. I got one 40mm fan and two 60mm fans. The fans were a little on the expensive side (the 40mm fan was $2 more than the 60mm fans) but reasonable enough. While I was checking out, I noticed there was a $5 "handling" fee. Clicking on More Information revealed that orders below $25 are subject to a $5 handling fee. My order came to $24.63 so I was $0.34 short. *sigh* I didn't have the energy to try to find a $1 item on their site so I proceeded. When I checked my account this morning, I found out that shipping was a little over $8. So a grand total of over $13 to ship $24 worth of fans that probably weighed a few ounces. I don't believe I'll be ordering from them in the future.
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Old Apr 06, 2012, 07:22 PM
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My fans came today. I think they are going to do the trick nicely. Here are a few pics of work done today. I have to remove the mechanics from the fuse to mount the exhaust fans. It shouldn't be that complicated to remove it and will make the fan installation a lot eaiser. The fans weigh 3.5 oz. total, something the heli shouldn't notice. I believe they draw about 0.1-something amps, which is nice as that won't afftect flight times at all.
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Old Apr 07, 2012, 03:09 PM
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I got the remaining fans mounted and tested everything. They only draw 0.1 amps. Now I just have to put the mechanics back in the fuse. Hopefully I can test it tomorrow, where the temp will be in the mid 70's. If the motor comes down cooler than last time, my efforts were worth it. If not... guess there's a new motor in my future.
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