Black Magic maiden update:

The Black Magic did NOT get its maiden flight this weekend. I did learn a few things though. I learned that the YS 160 is an expensive, angry, scary, feisty, incredibly powerful, thoroughbred of an engine that will bite the hand that feeds it and anything else that gets in its way (no one was hurt by the prop by the way). It is very sensitive to needle adjustments and will violently self destruct if it doesn’t like where it is set. I am confident that it is a great motor that will eventually power my plane through many successful flights, but it is a little bit different than running the pressured tank YS 120 FZs and 140 Ls that I am used to. Too lean and it heats up like Mt. Vesuvius, too rich and it kicks back like a mule, taking in my case, the spinner, the cowl, and the throttle servo with it.

This is how it happened:
I started it rich and it idled great, I started to advance the throttle thinking I would run it rich (the engine had been run before, just not by me). It got to about half power and really started pulling like gang busters. Then all of a sudden with a huge metallic KLANK the spinner, prop nut, washer, prop, and any sense of security I had went their separate ways. It was the kind of noise and sudden stop that makes you realize you have no idea what you’ve gotten yourself into. I collected all of the pieces and put it back together. The Tru Turn spinner looked like someone had run it over with a Buick and was no longer useable. Not being the type to quit I put it all back together to try again. Second try with the needle a little leaner was going fairly wall, I got to about ¾ power and it was really pulling. I advanced the throttle a little more and it started to show signs of pre-detonation so I backed off and leaned it out another click. It was making incredible horsepower so I figured I was close enough to try to open the throttle to full. I slowly advanced to full and boy was it moving some air. I started entertaining the idea of flying if and backed off the throttle to see how it idled. The engine idled great so I advanced to full again and without warning BANG if went from over 7,000 RPMs to zero. Uh Oh!!! I turned it over by hand and could feel some grinding. As it turns out, the prop nut was loose enough for the prop to turn against compression but it didn’t come off. I tightened everything back up and it all felt smooth again. A little head scratching and another two clicks lean and it was time to go again. Unfortunately that last kick seemed to have taken the cowl with it as it was hanging down with the mounting blocks completely gone. I took what was left of the cowl off and got ready to take another stab at it. Restarted the motor and it is idling like a champ. Advanced the throttle and it roared to life like an Allison Aircraft engine. Throttle response was instantaneous and power was amazing. One more run up and it will be time to taxi out. Ran it up and after about 5 seconds at full throttle it just wound down and went silent. It was so weird that I actually looked at the transmitter to see if I had backed off the throttle. Unfortunately the stick was still at full. What I did hear in the deafening silence was the unmistakable sound of a servo motor continuously turning as will happen when the gear train is shot. At that point I decided to pack it up, take it home, and mount the engine on a test stand. This week will be dedicated to making the minor repairs needed and getting the motor dialed in.

And that is how the first foray of my Black Magic ended.


I would like to thank Bob Kane, and Tim Jesky for putting on a great contest. The Black Magic and I will return!!