Would the power system out of a Brodak Super Clown (BH1850 motor and BH1846 11.1V battery) be enough power to fly a Ruffy (Wing Span: 50" Length: 34 1/4" Area: 545 sq. in) or a Stuka Stunter (Wing Span 47-1/4" Area 479 Sq. In.)?  The clown is Wing Span: 38 in. Plane Length: 24 in. Wing Area: 355 sq. in. so it is a good bit smaller but I've dialed the power/throttle back a bit to slow the plane down a bit. Brodak advertising says the BH1850 is equivalent to a .19 to .35 engine.

Charles, for something of that size you should consider motor power in the 475 - 575 watt range. I have no idea of the specifications on the Brodak motor so I can not comment on the power of it. You should check this out and decide if it will provide sufficient power to drive the larger model.

As far as using a 3Sor 4S battery you have to know what the kv rating is for the motor you will be using. If your motor has a kv rating in the 900 range you will require a 4S battery in order to have enough "head room" above your rpm setting. As long as your motor has a kv rating in the 1150 range a 3S battery is fine. Since the RSM 35-40 power system's motor has a kv of 1150 we specify a 3300 MaH 3S battery. This will leave you with 25-30% in the battery after your 5-1/2 minute flight so battery life will be good and long.

Hope this is of help.

Charles, for something of that size you should consider motor power in the 475 - 575 watt range. I have no idea of the specifications on the Brodak motor so I can not comment on the power of it. You should check this out and decide if it will provide sufficient power to drive the larger model.

As far as using a 3Sor 4S battery you have to know what the kv rating is for the motor you will be using. If your motor has a kv rating in the 900 range you will require a 4S battery in order to have enough "head room" above your rpm setting. As long as your motor has a kv rating in the 1150 range a 3S battery is fine. Since the RSM 35-40 power system's motor has a kv of 1150 we specify a 3300 MaH 3S battery. This will leave you with 25-30% in the battery after your 5-1/2 minute flight so battery life will be good and long.

Hope this is of help.

Thanks! This is a great help. The motor from the Super clown has a KV of 1500 and a max current of 35A. On the Clown it was turning a 9-4.5 prop. My other option at this time is a motor with a KV of 920 and a max current of 31A. It is a "rear mount" so would be easier to install.  I have no idea where to start for a prop for it. And I would need to buy 4s battery packs. $$$. There is no cheap way to get into this, or slowly upgrade: A larger motor requires appropriate batteries, ESC, charger, etc., etc. 

Hi Charles
My first electric stunter used the Super Clown motor and pack you mentioned in an Oriental - which is slightly larger than the Ruffy.  Since then I developed systems using 4 cells for applications in that size range.  The principal advantages for the 4 cell systems were the batteries were quite a bit shorter and a little lighter.  When I designed the electric conversion for the Brodak Stuka I also specified a slightly smaller (lighter) motor

What prop were you using on the Super Clown motor and  pack (3S I assume)? Can you give me some more details of that installation, the four cell system you used for the Oriental, and the system you designed for the Brodak Stuka?
Thanks!

Charles:
The Super Clown motor will handle an APC 10x5 nicely.  Don Still flew his Stukas with  Fox 25 on a 9x4 prop, but most folks I've seen use 10" prop. 

I designed a conversion kit (BH-1949) for the Brodak Stuka to convert it to electric.  The other day I installed a Super Clown battery in it - it fits.  The conversion suggests the Brodak Arrowind 2810 motor and a 4Sx2250 pack.  That combo is 1 ounce lighter than the Super Clown Motor & 3Sx3300 pack.  However if you got to the 3S system you MIGHT be able to downsize the battery to a 3Sx2800 with a tidy weight save and better pack size.  That depends on the airplane being light and optimizing flight time & RPM.

There is also a Universal "A" Electric conversion (#BH-1943) designed for fuselages that measure 2" wide inside dimension.  That should work for the Ruffy.  If it were me I would also build a sub-spare into the Ruffy wing so I could notch out the leading edge about 1" so I could have room to move the battery aft.

Hi Charles,
    I have what I call my CHAS(Cheap A$$ Setup)in an ARF Nobler and it works reliably over and over.I use a Turnigy 3542 1000Kv motor,Hobby King 40amp ESC,Hubin FM-0c timer and 2700mah Turnigy Nano-Tech batteries.The prop I have went to is an APC 10X5EP.This system has gobs of power to spare so it should work fine in either of those ships.If you want to get started in E-power and not spend a bunch of money this might be for you.Trax

Thanks for posting, good info