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Author Topic: Motor Size Elec. Super Clown  (Read 1222 times)

Offline Mike Evans

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Motor Size Elec. Super Clown
« on: May 18, 2007, 07:01:36 AM »
This winter I put together a Electric Super clown by Brodak. I did just the plane only. At the time and still can't find the specs for the motor they suggest. I don't like buying blind, I also have extra electric motors lying around since I fly Radio Control also. I haven't had a chance to fly this plane yet because of the high winds we've been having. Does anybody that put the Electric Super Clown with the recommended motor have the specs for the motor, amps, watts, KV rating, physical size, etc. However, I did install an A20-20L Motor in it. Which just barely fit in the cavity in the fuselage. I'm sure it's big enough but I'm still curious and would like to know the specs. of the suggested motor. Thanks, Mike Evans, Northwood, Ia
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Alan Hahn

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Re: Motor Size Elec. Super Clown
« Reply #1 on: May 18, 2007, 07:55:48 AM »
I am going to be heretical here, but if you don't already have the stock setup, I think the Super Clown would do better with a kV motor in the 1100-1200 range. This would allow it to turn a 10-6 to 10-7 prop in the 9krpm range and be able to use a 2100mAHr 3s battery for a full pattern (and lose a nanogram during the flight!). I have been looking at Scorpion Motors, and they have several  (2808 I think) which look like they would be a good fit. I am in a little hurry right now, but will try to say a little more this evening.
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Offline Mike Evans

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Re: Motor Size Elec. Super Clown
« Reply #2 on: May 18, 2007, 03:00:25 PM »
That was my thinking also when I started this project. The motor I installed has a KV rating of 1050KV per volt and is capable of swinging up to a 12 x 6 prop. I've got a bunch of batteries in the 3S 1800 - 2250 mah range. If I remember right I heard the stock setup is 4s, 4000 mah for the battery. but I am not really sure
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Offline Mike Palko

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Re: Motor Size Elec. Super Clown
« Reply #3 on: May 18, 2007, 05:15:39 PM »
AXI makes two suitable replacements for the Clown. The 2814/12 (1390Kv) and a 2814/16 (1035 Kv). There are other brands that cost much less, but I don't remember them all off the top of my head. 

I am using a 2814/12 with a stock APC-E 9x4.5 on a 4000mah 3 lipo. I don't think it's what you are looking for because it is still turning 12K+, but I can't see going to a lower Kv motor with a 6 pitch (personal opinion). The Clown will go through anything at any time with this setup. It out flies every IC powered Clown I have seen. It seems the lower RPM/high pitch setups loose more speed in the corner. (By corner I mean very hard turns as in sport flying. Picture an FAI wing with a 3.5"-4" pitch at 28-30K, they loose almost no speed in the corner)

The 2814/16 is more of what your looking for. It should turn around a 6 pitch at a much more reasonable rpm and give you a smooth flying airplane. I am not sure if you will get away with 1800-2250mah packs. They will only give you 1440-1800mah of usable capacity. You might be able to get closer if you shorten your flight times, shorten your lines, cut back on dia. or a combination of the bunch.

The stock Clown setup is a 3S 4000mah lipo.

Mike 

 
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Alan Hahn

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Re: Motor Size Elec. Super Clown
« Reply #4 on: May 18, 2007, 07:48:32 PM »
Here is the Scorpion motor I was thinking about (I was wrong in the designation). I won't disagree with Mike, because the differences between higher pitch, low rpm and low pitch high rpm are there. The main problem with the low pitch is that it is so darn inefficient---you have to carry around a bigger battery--although smaller than the stock 4000 maHr battery for the typical pattern.
I also include here my data from a recent flight (today!) on the Super Clown using an APC 10-7E (thin electric) and the stock motor. I am using a Castle Creation 35 A ESC since I need to throttle down the power. I am guestimating I am running at roughly 2/3 throttle--it is a little hard to figure exactly since I am running in governor mode. Anyway I am running ~8500 rpm with this prop. Statically it is drawing >30 Amps (I released before 8500 rpm was reached. When you compare it to the Scopion motor, note that it is drawing 26.8 A from a ~3 cell lipo. For me, I am effectively wasting the third cell due to the throttle down. What I am saying (or trying to) is that the Scorpion setup with a 3 cell Lipo will actually draw less current than I am currently drawing. In my case the 2100 maHr battery is marginal--I am sucking too much out of it. With the Scorpion I think a 2100 maHr battery is probably fine. Also realize that a  3 cell 2100 maHr battery weighs ~6oz or so, compared to the stock 4000 maHr 11oz weight. The 2100 maHr battery is in the $60-70 range.
I think the stock setup could fly comfortably with a 3200 maHr battery, but those are pretty pricey compared to the good deal Brodak offers for the 4000 maHr battery (~$90)

oops, I put the wrong Scorpion motor in. I meant to put in the 3008-28 motor (kV=1253) not the 3008-32). If you were a real "motor" man, you would buy the kit and wind your own motor! Anyhow here is the 3008-28.
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Alan Hahn

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Re: Motor Size Elec. Super Clown
« Reply #5 on: May 18, 2007, 08:20:06 PM »
Note that I included the Scorpion brushless motor primarily because they actually give rpm and current draw (static) for the same prop I am actually using now, so I know how it would work.
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