After opening my mouth about 1/2a Engines and changing to electric, here is a version of my first flight after work today.

I tried to keep faithful to what we traditionally call 1/2A----it was easier since I was planning to use this plane in Jim Renkar's 1/2A Contest where the only requirement was that the prop not being bigger than 6" in diameter, so that means no big prop turning slow rpms.

I chose the particular airframe because I already had it and used it in last year's contest, using a BlackWidow engine on the bulkhead mount. When I removed the BlackWidow, I weighed it and the plane--the Black Widow weighed 2.1oz (without fuel) and the plane, without engine weighed 3.9oz. Together the total weight was 6oz. I flew it on 42 foot 008 lines.

So I tried to find a power combo that was in the ballpark of a fueled up BlackWidow--probably in the 2.6 oz range. I think I came pretty close---the final all up weight of plane+ power system, including charged battery, was 6.9oz, about a 1/2oz or so heavier than the glow version.

I had to modify the front end of the Baby Clown to allow a place to put the battery, and to put the prop nominally where it was with the Black Widow. From the photo you can see I spliced in a 1.5" extension, with a small cheek cowl (to give me somewhere to bolt the motor mount to).

So here is the setup for electric costs
1) Gobrushless GBx1 Brushless Outrunner motor--this was a kit that I wound with 11 turns of 22 gauge wire to give a "kV" of 2250. Total weight including the motor mount was 36.5g (1.3oz)--$26.50 +$4.60 S&H
2) Thunderpower ProLite 2s730mAHr battery 32.3g (1.14oz). ($30 S&H free!)
3) Castle Creations ThunderBird 9Amp Electronic Speed Control (ESC) $26 +$4.60 S&H
4) JMP-2 timer control $30+$4.60S&H

Miscellaneous connectors ~$6

I don't include my charger since I already have it ($60), but one can buy chargers in the $30 range.

So today I flew it for the first time. Used an APC 6-5.5 Electric Propeller, setup for ~2 minutes of flying time. This time is consistent with the time to fly the beginner pattern (the contest requires only the beginner pattern for all skill levels). I wasn't too sure what to expect. The motor was able to turn this prop at 11.7 krpm statically on the ground. This sounds low compared to a Blackwidow ~15-16k rpm, although typically there I am using a 6-3 or 5-3 prop. I used 35 foot 0.008 lines.

I was pleasantly surprised to see the plane take off from the grass field and really fly well. As a matter of fact, it felt pretty fast (maybe too fast) in the air. Was easily able to do the whole beginner pattern--ok ok, not a great pattern! (first flight of the year). Finished with plenty of time left on the timer. I'll post the amount of charge left in the battery as soon as it finishes charging [added later---use 240/730 mAHr total capacity]. Only have a single battery at this stage, because I wasn't willing to shell out more until I saw how this would work.

Also will mention it was 33^oF outside, but the wind was light. However most of the snow was gone!

Here is a link into the Electric Forum which gives more of the gritty details on how I got to this stage.
http://stunthanger.com/smf/index.php?topic=8350.0
And here is a picture after the first flight. As you can see, I am using Larry R.'s RSM handle.

Alan,

Sorry I missed the 1st flight.  I may miss work again today....nasty bug.
Hopefully, I'll have my camera along when you fly this again.  I'll take some stills and video.

Your stooge,
Fred

Jeffrey,
I think I would be ok at somewhere between 4-5 minutes, but it would take a few more flights to find the right throttle setting and/or prop. With a Lipo battery, you don't really want to suck out more than ~80% of its capacity---which would be (let me get my calculator)  580mAHr. This is roughly 2.4 x what I used, so perhaps almost 5 minutes can be had.

But like I said, 4 minutes of a 1/2 a is a lot of spinning. 1/2a is the "fast lane" of stunt. I don't know if I could walk a straight line after a 4 minutes flight. That's way more than you would need for a full pattern, unless I would slow this plane down.

I did bring some 42 foot lines, but today the wind is gusting to 20+mph. Maybe it will calm down by 5PM.

what about lil jumping bean with a foam core wing?  I think that would work better.  then you could store the battery and gear inside the wing. 

I posted a short video of Alan's electric Baby Clown.  The flight was yesterday at noon.  After the flight, Alan realized he had mounted the wrong prop.



Fred 'The Stooge'

Alan,
May I suggest that you get in touch with Russ Gifford concerning your electric Clown.  Ya know, He loves electric! 

Alan,
I got the email.   

I love it!

Hey Alan,
Why don't you try another prop?  A 6 inch 6 bladed prop.  That ought to make 'em squirm at Renkar's contest.   

BTW, I like the pilot!

Not trying to jack the thread I have a question on blades and power usage. Would trimming the blades 1/4 " reduce usage and increase rpm or ?   still trying to understand the dynamics electric flight.