Expert: Colin Woehrle - 4/3/2007

Question
I was writing to find out a little more about small turbine engines. I am flying enthusiast, but have never actually piloted a plane. Once I am finished with graduate school (for my MS in criminal justice), I hope to not only have the time, but also the money to take lessons and get my license. I am interested in small turbine engines because it has always been my dream to build my own aircraft. My interest in small turbine engines was sparked by Yves Rossy (aka. jet-man) and his "jet-pack" (nothing more than 4 turbine engines and wings, pretty simple). However I am interested in a much safer, and much larger craft. How much thrust is generated by the engines? Also how do the engines work? Mr. Rossy had to jump from a plane before he could turn on the engines, why? Thanks for any help you have to offer.

Answer
Hi Mike,

Yves Rossy stirred up quite an audience with his jet pack, didn't he? Well from what I understand he used two model airplane jet engines that produce around 45 pounds of thrust each. There are a couple of reasons I believe Mr. Rossy jumped from an airplane. One is that he had limited fuel and limited power. If he took off from the ground, which would be very difficult and extremely painful to the face without wheels and tires, he wouldn't have had enough fuel to reach a comfortable soaring altitude and his short flight wouldn't have lasted as long as it did. Another reason could be because of his weight. He probably weighs in between 150-200lbs, somewhere around twice his total available thrust. He would most likely run out of runway before gaining enough speed to fly. So it would just be much easier to already be at altitude and attempt this feat. Also if something went wrong, and he needed to bail out, he would have sufficient time to deploy his parachute and land safely.  

These model turbine engines work like most other turbines. The four basics of operation are, in order, intake of air, compression of air, introduction and ignition of fuel, and the exhaust out the back. Sounds a lot like the stages on a reciprocating engine, huh?

Thanks for the question and good luck with graduate school!

Sincerely,

Colin Woehrle