[4stripes]

Recently I experimented running a Changesun 10 blade fan on the stock Habu BL15 3200kv motor in the stock Eflight shroud (from the Habu).

The resulting sound improvement was huge. The shroud had to be modified with a dremel to allow the adapter to sit farther down the motor shaft by reaming out the hole. Next I dremeled out the shroud cooling holes toward the sides to get maximum flow to/from the motor cooling holes. Lastly a pair of Hobbyking cooling fins were glued to the back end of the motor with JB weld.

The collet style adapter was secured with locktite after sanding the motor shaft. This makes it very secure, to the point where you will find it impossible to remove! The cooling fins were added after mounting and balancing the motor by cutting the shroud motor support stands then dremeling a notch into the flat portion which rests against the motor can. Once the tab is weakened with the dremel, the piece can be broke way with needlenose pliers. I roughened up the motor surface and cooling fins to give the best grip for the JB weld. The cooling fins reach more than 1/2 way round the motor can so 1/8" was trimmed from the ends of each set of fins. This way both can be put on the motor surrounding it 360 degrees.

Dynamic balancing started with repositioning the fan on the adapter until the smoothest running position was found (without the spinner). Once the fan was secured in the best position, the spinner was installed and repositioned untill the best running position was found as well. Lastly a small piece of Duct tape was applied to the spinner a various positions to find where additional weight was needed. Only one small drop of CA was added inside the spinner to make it run dynamically balanced. In fact I had to scrape a little of the CA out as it was too much weight>

Sounds great and the Gens Ace 4S 25C 5500mah battery produced burst draw of 73A settling to 67-68A about halfway through the battery charge. The settled current is approx. 1000watts at 14.7V. The motor does get warm, but stabilizes around 135F. My testing was done with a combination of WOT and 1/2 throttle alternating back and forth like a typical flight. If it was run WOT continuously for the whole battery, the motor might not take it but that isn't how most flights are made.

If you plan to upgrade your Habu with one of these 10 blade fans, be sure to upgrade the ESC to a minimum of 85A AND mount it in the duct where it can get adequate cooling. There is a 12 blade vedsion of these Changesun fans but the amp draw is about 7-8% higher than the 10 blade which might push the motor past its capability.

[ogopogo]

sounds like a lot of additional amps required just to change the sound Eric. Bigger battery, bigger ESC, cooling fins ..

cheers
john

[4stripes]

Although it draws more power, I'm pretty sure it will produce more thrust even with some efficiency loss.
The main reason for the change was to improve the sound, which it most definitely does.
Can't wait to see it preform in the plane. This fan was built for a friend so it will happen when he has time to install it.
Cheers

[ogopogo]

just remember we like video . It's a great trainer in stock configuration but certainly seems lethargic after a while. Anxious to see your results. I am putting an 8S Schubeler 4-blade in a BAE Hawk and I know the sound will be less than desirable but don't know if I can spare the amps for sound improvement.

cheers
john

[4stripes]

Will post a video for sure John! I've been running only "quiet" fans for the past 2 years. The extra draw isn't that much. My flight times were roughly the same when I was running 6 blade Wemo midi clone fans but in most cases the motor has to be switched for something with lower KV. This Habo switch is pretty cheap as you only need the fan and a better ESC. The stock motor/shroud/battery is fine.
Keep us posted on the Hawk! I have the FlyFly composite version to work on this coming winter. It is heavy enough I think it needs 8S as well.
Cheers Eric

[4stripes]

Fan/motor combo is now mounted in the Habu with an 85A ESC mounted flush inside one of the ducts. The stabilized draw is 68A/900watts. Didn't measure the original but I suspect this is probably 8-10A higher with slightly higher thrust.
Will post a video as soon as it is flown.
Cheers

[ogopogo]

fly it today Eric and you can probably get 200 mph downwind . just like a fall day. Oh that's right, it is fall - crap.

[4stripes]

I did this for a friend, so perhaps he will fly it this weekend...

[pritz]

I have flowen the Habu with 4 Strips balanced fan 2 times now. Both flites were on very windy days--so not much fun! However, all fellow pilots were amazed at how quiet the Habu was and seemed slightly faster. One Turbine pilot said " I like that COOL jet-like sound! The general concensus was " infinitly better sound". Our weather has been crappy lately; but I live 5 minutes from our field so I can nip-up whenever there is a weather break. Hopefully we can get a Vid with the new sound before the white stuff arrives. Thanks Eric for balancing and insalling the new fan and relocating the ESC in the duct. Cheers Ted

[Max]

Good stuff, Ted. Thanks for the detailed explanation of the modifications, Eric