Boomeran 40 trainer - RC Groups
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Jun 23, 2007, 09:36 AM
Registered User

Boomeran 40 trainer

Hi Im currently converting a boomerang to electric.
the following is my selected setup. Im worried the motor isnt up tp the job..for weight of plane.
let me know what you guys think..

motor 3520-t7 600w 600Kv max current 46A
14x7 prop
6s2p 4350mah lipo (2 x 11.1v 4350mah lipos)
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Feb 09, 2010, 06:46 AM
Astrowall's Avatar
Not sure on your setup there... as I am no expert, but I am converting my Boomerang 40 now also... Plan on putting in a Turnigy 42-50A 700Kv motor, 12x8 prop, 60A ESC, 4s 4000mAh battery. Conversion seems to be running very smoothly, and just finished an access hatch to get into the battery etc... I have also added some air scoops to direct the air into the cabin. Progress pic below. I have just finished painting and reapplying the black window, to make it look the same as the original.

Click on image for enlargement.
Feb 12, 2010, 09:32 PM
Look out for trees.
Plane looks very similar to my TH .40 trainer (same plane different label?); though it may be completely different.

But here's my progress so far: TH Trainer Thread
Most difficult part for me was making something to mount the battery onto (oh and removing the gas tank... i realllllllllly glued it in there apparently).
Mar 05, 2010, 03:53 PM
Astrowall's Avatar
Got the electrics for my conversion now. Turnigy SK 42-50 650Kv, 60A ESC, 12x8 Prop and 4S1P 3000mAh Battery. This setup was tested in a classic 40 trainer, very similar to the boomerang, maybe slightly lighter. It flew with lots of power in reserve and long flight times >10min so I think I am happy enough with that to put it into the Boomerang.

Here is the Boomerang with hatch finished but needs motor installed.

Click on image to enlarge.
Mar 06, 2010, 12:44 AM
Astrowall's Avatar
and here it is with motor and other electrics installed...

Click image to enlarge
Mar 06, 2010, 12:57 AM
Astrowall's Avatar
Here is the exit hole I did, to allow the air to flow through. The hole was cut out then a piece of Flywire was put over the top and epoxied into place, then painted afterwards.

Click image to enlarge.
Mar 06, 2010, 10:44 PM
Astrowall's Avatar
Okay here is the complete write up with images linked in...


I thought I would let you all on some information in regards to converting a 0.40 sized trainer to electric. Sure the smell of Methanol is good, but wouldn't you all like to go home not smelling like it, not cleaning it off the plane etc...

I had an O.S. 46AX engine in my Boomerang Trainer and thought, why not convert the plane to electric. It's cleaner, I can just plug a battery in and go. Don't have to waste time playing with the tuning etc... I wanted flight times similar to that of the fuel so I had to do a bit of research. Flight times with the below config will give me between 10 and 15 minutes depending on how I fly.

Motor: Turnigy SK 42-50 650Kv
ESC: Turnigy Plush 60A
Battery: 4S1P 3000mAh 20C Lipo
Prop: 12x8
Performance: 8800RPM @ about 35A.

More than enough for the Boomerang.


SO I set out and modified the top of the Boomerang to allow a hatch to be installed.

Added some airscoops to the sides and in the hatch also.

Made a new hatch out of some spare balsa wood and plywood. and Fibreglass the inside of this for strength.

Painted the hatch up and applied the original window decal to it..

Made a new firewall. this ended up being about 40mm further forward.

Added an exit hole for the air to pass through the plane, the mesh is just flywire from a window. Epoxied on.

and added the electrics to it.
Mar 14, 2010, 03:14 AM
Registered User
What was your cost on your conversion. I just got a 40 size trainer cheap and been thinking of doing an electric conversion.
Mar 14, 2010, 08:23 AM
Astrowall's Avatar
All parts were from HobbyCity.

Turnigy SK 42-50 650Kv Motor US$25.95

4S1P 3000mAh Lipo. US$32.28
You can use any 4S battery with similar specs.

Turnigy 60A ESC. US$32.85

12 x 8 Propeller. US$1.89

Total cost for 1 of each came to US$92.97
Apr 28, 2010, 08:31 PM
Big Goof
Hi Astrowall,

have you flown yours yet, or still in the process of converting? I've been thinking of converting the Sig Kadet that's been hanging up in the garage and this setup looks great.
Apr 29, 2010, 03:28 AM
Astrowall's Avatar
Yeah I flew it and it flew great, had about a 15minute flight before bringing it in. Motor was cool, ESC was cool everything was cool... Worked great..
May 01, 2010, 11:35 PM
Big Goof
Sounds good. Looks like that motor is currently on back-order, but I'm gonna buy the same system you describe and get my old Kadet back in the air
May 02, 2010, 01:18 AM
Astrowall's Avatar
Yeah has been in the negatives for some time, I want to get some more, but will wait until they get more stock in, same with the ESC.
May 02, 2010, 11:54 AM
Airliner Builder
WAGliderGuy's Avatar
Wow nice conversion!

I am converting a 1989 Aerostar .40 kit my grandpa built. I got all the same supplies expect the motor is a little less powerfull, only 770kv (its a KDA from HK) and I got a 4S 30-45C 5000 mah battery. Do you think it will get off the ground? I am calculating about 600 watts of power and the RTF weight should be around 4-5 lbs.

May 02, 2010, 04:18 PM
Astrowall's Avatar
Hi WAGliderguy, It should fly no worries there I think, SHoul fly like a trainer should. Not sure of the weight of the motor but having the larger pack should help in the balance. I know I added a small amount of lead in the nose to help balance it out. I could remove this by going up a few notches with battery capacity.

Look forward to your results.

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