http://blog.aopa.org/helicopter/?p=841 AOPA's Helicopter Blog Tue, 21 May 2013 12:38:25 +0000 hourly 1 http://wordpress.org/?v=3.5.1 http://blog.aopa.org/helicopter/?p=841#comment-2448 NeilC. Tue, 02 Apr 2013 17:32:00 +0000 http://blog.aopa.org/helicopter/?p=841#comment-2448 Tim, you are mostly correct in your writings. Be aware that there is a ‘warm-cycle” exhaust from turbofans that have reduced temperatures and new compounds for those problematic rotating gas bearing seals. They never tried any more than 2 bladed rotorhead. The Keller pressure-jet is a rotorhead design that the late Merrill Keller has a patent on that has not been tried. He was passionate about his design and felt like it was the future of helicopter aviation. I hope that one day his dream will be realized as a major advancement in helicopter safety.

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