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Old Sep 13, 2013, 12:41 AM
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rrcdoug's Avatar
Canada, BC, Kelowna
Joined Aug 2010
215 Posts
Good news TB!
That's some mysterious magic smoke that came out of your motor! The one that quit on me did so in the air so I saw no smoke. I really am impressed with the capabilities of these cheap outrunner motors. Drive calculator suggests that the 14X8 prop is not as efficient as the 13X8 prop. I just put the 13x6.5 back on the nose after trying a 16X6. The 16x6 used more power for only slightly better performance as predicted by Drive Calculator. I get almost as good a climb with that little 13" prop plus I can span a 3 cell - 4 cell range on the battery.
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Old Sep 14, 2013, 12:49 PM
Registered User
Tampere, Finland
Joined Oct 2009
157 Posts
Here is my reasonably priced set-up:
-motor Robbe 35-42-05
-controller ENERG PRO B-65A SBEC 5A ESC
-propeller Aeronaut 12x6,5
-battery 3s 1300 mah Lipo, 30C Robbe.

Takes a 3.8m E-Xplorer to 240 - 260m in 30 sec. Battery took 422 mah, motor time+ 12 min flight. Plane weighs about 2050 grams ready to fly (72,2 oz). Wing is a ST F3J wing, fuselage v-tailed electric with the servos almost underneath the tail. No noseweight needed, I calculated/tested how much the motor + controller + battery should weight and chose everything according to that.
Tommy
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Old Sep 14, 2013, 04:05 PM
Balsa addiction since age 3
ScottSails's Avatar
Upstate NY
Joined May 2005
1,262 Posts
I have used the same EMP motors as the OP in my 2.5-3M ALES planes (and old gliders) for the last 4 years and swear by them. I have gone through the 790kV, 900kV, 1100kV motors and have pretty much settled on the 1100kv at about 50A peak, 3 Cell (limited to 30 seconds). I do caution that I really don't believe these motors can handle much more than this safely. 50A 4C is asking for trouble (I have done it).

The 3 Cell configuration gets me pretty well to 200M within 28 secs no problem. I am using 10x6 (36A) on my 2.5M planes (47oz) and 11x6 (48A) on my 60oz 3M. I try to stick around 50-65mph static pitch speed (so I can move out). These are all Aeronaut folders with 35-45mm spinners.

For those using the Turnigy Nanotech, I have tried 6 different 1300mAH 45-90C and they could not sustain rated current (or even close, they peter out at 31A). For what it is worth, Sky Lipo 1300mAH can easily pull 40A sustained as well as the 1300mAH from Value Hobby (the non-nanotech ones) - both about a 1 volt drop under 36A load.

Best wishes,
Scott
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Old Sep 25, 2013, 08:43 PM
Addicted to lazy-flying models
azdiane's Avatar
United States, AZ, Chino Valley
Joined Apr 2013
122 Posts
yuk yuk

It's obvious that our model aircraft electric motors and ESCs have a lot in common with the avionics in full-size airplanes. They work because of smoke.

Well, if you don't believe it, once the smoke comes out of them they don't work any more.
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Old Sep 26, 2013, 11:10 PM
Kipp G
Dixon, Ca.
Joined Mar 2004
166 Posts
Try this motor

Hey guys, me and my friend Mike have competed all season with the Turnigy 42-48 prop mount on 5s 2200's. We run a HK woven fiber 14x9. It puts out 1340 watts at about 72 amps. It's in the e-Sharon 3.7 from Soaring USA. Total weight is 104 oz. It will outrange anything at the ALES contest. Everything in it is HK bought. Crazy power without a gear box. Motor is about $30. Food for thought.
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Old Sep 27, 2013, 06:58 AM
Registered User
Joined Oct 2008
140 Posts
Just a quick update on how things have gone with my el cheapo set-up based on the OP's set-up now that I have flown the plane a lot more.

I'm absolutely delighted with its performance! I have stuck with the 13x8 prop as it gets the plane to around 200metres in about 20-22 seconds. After 2 launches to 200metres it has taken about 380-450 mah from the 1000mah 4 cell Nanotech battery. Its obviously pulling far less amps in flight than it did on the static testing. After launching to 200 metres I brought the plane down to feel how hot the motor was and it was barely warm to the touch! The plane btw weighs 1980g AU flying weight.

So this set-up gets a big thumbs up from me. The fact that it cost me very few dollars to get it in the air again is great. That I'm flying and enjoying a plane once again that I designed over 27 years ago.......priceless!

TB
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Old Sep 27, 2013, 12:00 PM
agnotology
kcaldwel's Avatar
Joined Jan 2007
3,654 Posts
TB,

Thanks for the update, and I'm glad it is working well for you.

I originally chose the prop using eCalc, but I may have to try a 13x8 or 14x8. You are getting good climb rates.

I have expensive MVVS, OS, Plettenburg, and other motors, but I just don't see the advantage of spending hundreds of dollars if I don't have to. Certainly for 30 second ALES climbs, these motors are more than adequate if you have space for them.

The weather has started to turn to fall here, but I'm up to about 450 flights on the motor, and 225 cycles each on my $12 Nanotech batteries, still going strong.

Kevin
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Old Oct 13, 2013, 02:16 PM
Registered User
Joined Oct 2006
38 Posts
Thank you Tommy

Quote:
Originally Posted by Tommy Wee View Post
Here is my reasonably priced set-up:
-motor Robbe 35-42-05
-controller ENERG PRO B-65A SBEC 5A ESC
-propeller Aeronaut 12x6,5
-battery 3s 1300 mah Lipo, 30C Robbe.
Thank you for the tip

I copied motor and propeller for my old style (nr 278) carbon supra 1840 gr empty. Cheap esc (don't use the bec because of HV servo's) etc. All ready for < 100 euro incl 2 battery packs.

Willing to be surprised

John
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Old Oct 14, 2013, 07:36 AM
Registered User
Tampere, Finland
Joined Oct 2009
157 Posts
Quote:
Originally Posted by dutchsoarer View Post
Thank you for the tip

Willing to be surprised

John
You are welcome.
I hope it works for you, it did for me

I tried also 12x8. It did go up slightly better, but the Amps went higher and it seemed that the battery surrendered under the load. 12x6,5 is a good compromise. If your Supra's flying weight ends up at around the same weight, it should do well. No rocket, but it wasn't meant to be. F5J is a tactical sport, if you start too high it will be severely penalised...

Tommy
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