A weirdo for a weirdo?

This spinner story began when I wanted to push the electric motor of my new Turbo Beaver from Extreme Flight to its limits. According to the manufacturer, a 6S battery should be enough to make the model—with a 2-meter wingspan—powerful enough for any purpose, including aerobatics, 3D (!), and F-tow. And if you watch the flight videos on YouTube, you’d believe it, too. It’s worth noting that this extremely lightweight wooden model, ready to fly—including a 6S 5000 mAh LiPo—weighs just 4.1 kg and has absolutely fantastic flight characteristics. For the powerplant, I chose an affordable option: Potenza 60 470 K/V, Skywalker 80 A Opto ESC, and 16x7 APC-E propellers with a 65 mm spinner. At full throttle, it drew 70 amps, and the static thrust was 4.6 kg.

Already during the first flight on a truly extremely hot afternoon, after revving up vigorously and hovering for extended periods at times, the engine began to make clattering noises and completely stopped working after about 7 minutes. A quick touch test revealed that it had become extremely hot and had apparently met its heat-induced demise inside the long turbo nozzle.

Next came the second attempt with a new Potenza engine. As a precaution, I ran it without a spinner. Now I could rev it up and tow it to my heart’s content!

But a Turbo-Beaver without a spinner really does look like s... and I couldn’t resist the temptation to try flying the model with a spinner again, just for the sake of it. It could have been that,

that the first engine was a Monday morning production model and the new Potenza is significantly more powerful. But I shouldn't have done that, because the same thing happened again: After driving it hard for a while, this engine also started smoking.

Now I knew for sure that heat was actually building up in the narrow, long turbo nose. The air intake, mounted relatively far back on the hood,

The intake opening, combined with a relatively large ventilation outlet, apparently didn’t provide any cooling effect. So I sent an email to the folks at Extreme Flight and explained the whole situation to them. They said that no problems had been observed with the motor they recommended, a Torque 4016/500 KV. But since that motor wasn’t available here, I decided to go with a different, higher-quality motor—one that was about twice as expensive. The Scorpion SII-4025 440 KV, controlled by a Castle Edge 100A ESC, now powered a 17×8 APC-E propeller and delivered a remarkable 5.2 kg of thrust at 80 amps. As a precaution, I operated this powerplant only without a spinner. It got quite warm during towing, but not hot. Still, the sight of this beautiful model without a spinner was a constant eyesore...

But then I discovered the Turbo Spinners at the store and bought several different sizes. These spinners are precision-manufactured—

It featured aluminum base plates and perfectly round plastic spinner caps with angled slits that draw in air and direct it through the air-permeable base plates exactly where it needs to go in a brushless outrunner motor—namely, straight into the front of the motor. Now came the moment of truth: I put the Turbo spinner through its paces with a heat-up and a towed flight. The motor barely got warmer than lukewarm. In the meantime, I’ve also equipped my Ryan ST-A (2 m wingspan, 6S, Leopard Brushless LC5065-8T) and various other models with these Turbo spinners and have never had any overheating issues again, even on hot days.

These spinners are available from HEBU in Entlebuch or can be reliably ordered online at www.hebu-shop.ch and delivered by mail within 2 to 3 days.

Low cost, minimal effort, maximum impact...