I'm looking to find a good cheap combo for a Blackhawk Models Super Stunt Master electric conversion. Nominal 40" span with 450 squares (no flaps), short coupled tail, and an expected flying weight in the mid-30s. I would say it's going to end up about the same size as the Super Clown.

Now, I have the BH-1833 electric package that I got for my Super Clown ARF, but the odd mounting of the motor kind of throws me (3 bolts instead of 4). I would prefer something that is standard.

These are the motors I'm looking at:
https://innov8tivedesigns.com/tempest-2814-1050kv-brushless-motor.html
https://innov8tivedesigns.com/cobra-c-2820-10-brushless-motor-kv-1170.html
https://innov8tivedesigns.com/badass-2814-1300kv-brushless-motor.html


According to the performance charts, they all look to be able to spin a 9x6-E prop around 11k on a 3S battery. I don't have any issue bumping it up to a 4S battery, as long as I can get it to fit in nose.

I'm hoping that it'll generally be an electric replacement for the classic Fox .35, just without the vibration issues on a profile. The profile mount I'm strongly considering is the Brodak BH-1938 electric conversion kit for warbird series, mostly because I have it on hand. I'm open to suggestions for a better mount, even if it means I just need to 3D print a custom mount. The main thing (to me) is that I have a good motor and enough battery to get through something akin to the pattern (~5-1/2 to 6 min flight).

Steve

Hi Steve
First off the Stuntmaster should be an excellent conversion.  It is bigger than the typical profile in its class and as I recall has a nice looking airfoil - should work well.  You are going to have a bit of a challenge due to the short nose and battery interfering with the wing - you will probably need to notch the leading edge.  Because of the short nose balancing could also be an issue so while smaller motor might work from a power standpoint it might not balance.

I work with Brodak, and thus my recommendations lean toward the Brodak products but other "brand X" parts can usually be substituted.

First off, I think one of the Brodak conversion kits could be adapted to the Stuntmaster, and it could save you some work.  The conversion (#BH-2018) for the Flite Streak  is designed to put the thrust washer of the motor about 5.25" forward of the wing leading edge and pockets the battery 1.5" into the leading edge of the wing.  Check that against the Stuntmaster plans and see how it compares.  I also attached the assembly manual so you can see what its all about.  The conversion can be built to use either front mounted or rear mounted motors so it "checks the box" for accommodating standard motor installations.  It is designed to install the battery from the inboard side of the fuselage so a Velcro strap and centrifugal force retain the battery.

Recommended power system, from Brodak which has all the connectors installed and is ready to "plug & play":

PROP:  APC 9x6EP turning roughly 10k.  Lots of folks fly this size airplanes on 10" props but my experience is that 9" props fly better on flapless airplanes in the 350-500 square in range.  6" pitch reduces battery usage versus a 4.5" pitch.
MOTOR: Brodak 2814 (aka 3536) 900 kv, (#BH-1840) This motor is designed for rear mounting.
ESC: Brodak 40A (#BH-1860)
BATTERY:  Vant 4Sx1800 (#BH-1890).  This a short (89mm) light (6.2 oz) pack with the capacity to fly a full stunt pattern in Stuntmaster sized airplanes
TIMER: Hubin FM-0c (#BH-1869)  This timer lets you set engine speed and flight duration (From 1:45-6:00), used i the BH-1833 package you mentioned.

You mentioned other motors - indeed there are LOTS to choose from, I suggest something roughly the same size (2814) and:
* For 4S the motor kv should be in the 900-1000 range.  Battery capacity between 1800-2200, with "C" rating of 25C to 35C
* For 3S the motor kV should be in the 1300-1500 range.   Battery capacity between 2400-3000, with "C" rating of 25C to 35C  You may have trouble finding the higher capacity 3S packs that are also 105mm long so they may not fit.  The battery box described above is 120mm long.

* ESC with at least 30A capacity, simple non-governing aircraft ESC's can be used because the Hubin Timer has a "throttle up" function built into it that adds throttle over the duration of the flight to compensate for the battery voltage dropping off.

* Timer: I am not aware of a better choice available for this kind of airplane


Hope this gets you started, I'm sure you are going to gt a lot of other advice..!

Here's a 4S 2800 Li-on pack I made up for my Top Flite Combat streak. (pretty short nose!)
197 grams.(Same as a 4S 2200 lipo Thunder Power pack EXCEPT its 2800mah.)

The introduction of the Li-ion packs should give us shapes that fit the smaller shorter nosed profiles.  Only issue will be finding sourced willing to build them.  Not everybody is a DYI when it comes to batteries!

Ken