I've had several people, Ed Bridant among them, tell me about converting the Li'l Hacker to electric.  So I started researching and found what I think is the right stuff.  WAG calculations gave me 140 watts in, ~110 at the prop.  That led to the first big decision.  There is no way to get that kind of power out of a large battery.  Even 1000 mah is on the heavy side for real performance.  I also wanted to fit it into the wing with the flat side forward in case of a crash, limiting the battery to about 1in. wide.  But E-Flite came to the rescue with a 3 cell, 30C, 800mah battery that weighs about 58 grams complete.  I dug up a Turnigy 2820/1650 motor, rated at 16 amps.  At that power draw I figured a bit over 3 min.

Test runs in the winter here confirmed it pretty nicely.  It turns a 7/5E prop around 15,000 rpm.  At three minutes the motor is barely warm.  At 3min. 20 sec. the Castle 25 shuts it off.

I can hardly wait for the weather to break to try it out in the air.  The total power package weighs a bit less than 90 grams, just about 3 oz.  That compares pretty favorably with a TD or Norvel at 1.5 oz. with another 1-2 oz. of fuel.  That big prop sure does move a ton of air.  It blew pieces of foam and other stuff off the bench and all over the place.

What do you reckon it would take to make an electric F2D practice plane?

Have a look at this on Claudia Kehnen's site; http://www.fesselflug.eu/html/f2d_-_elektro_combat.html

There are some videos to look at as well. My German is not too delicious, so I clicked on the  translation button and the word "combat" came out as "fox-hunt!" Maybe it meant Fox 36X??

keith R

"Has anybody pursued the idea of stopping the prop in the horizontal position by some electrical trick?"

That is what one of the electric speed guys was working on a while back.  Maybe someone knows who that was
and the results.

I've been fooling around with this for a while in between making my governor system work, and I've tried the MVVS 2,5/1480 motor that is an IN/OUT runner. This is a high quality really tough design with the drum inside the casing, and you won't bend the shaft easily. I tested it with a 3-cell pack but it does not have enough rpm. I'm thinking that I need to try it with 2 x 2 cell packs because the 4-cell small packs are hard to get. The motor's weight is higher than normal at 109 grams but that's because of the extra casing etc. The connections at the back are also nice. My first test was using a standard Russian type wing, and the CG was too far back, even with the heavy motor, so I need to design a new wing especially for the electric stuff.

I used my governor timer, not because I really wanted the constant rpm, but because my system shuts down when the prop rpm goes lower than a pre-set amount, or in the case of hitting the deck. You connect the extra wire from my timer to any one of the motor wires, so the rpm is monitored all the time. I even use this on my 1/2A trainers because most beginners hit the deck all the time and you don't want to burn out esc's and motors all the time. I just need to find a little extra time to build a new wing, and then I'll try this again.

Thanks, folks.  Is there a US supplier for the MVVS 2,5/1480? 

If you can't find a source locally, then Alberto Parra is most likely your closest source http://www.clubtamaran.com/electricos2.htm

Keith R

Wow.  Thanks.  That looks really cool.  It's probably made specifically for Phil's plane from the looks of the name.