Hello to all you seekers of*knowledge*and*speed!
I feel compelled to share with you my propeller experience, and the resulting education.
I purchased a nicely built, stock, 118HP Lancair 235 recently. The one reservation I had with it was the IVO propeller the builder chose. The aircraft sat unflown for many years, and more recent experiences had revealed that the IVO prop is unsuitable for Lycoming 4-cylinders; harmonics caused several prop failures.
I nonetheless operated the setup for 15 hours, finding it to deliver 148 knots TAS at 4500' dalt and 2800 revs. During that time I observed the prop manufacturer's SB mandated inspection schedule. The prop soon failed by cracking it's hub adapter, thankfully without a catastrophic in-flight separation.
Meanwhile, I had been researching props prior to the failure and found Paul Lipps' designs quite intriguing. His reasoning resonated with me, so I ordered one. I found it odd that his design, built by Craig Catto, was priced on par with Catto's own designs. That is, until I met Paul in person. It seems to me that Paul's motives are simply in designing things as well as they can be. His own plane drips with his aerodynamics passion (except in its finish - sorry Paul). This is also illustrated in his recent post:
"I'm not interested in selling propellers; this is something I do to support those who are interested in more performance. With me it is a hobby just as the electronics I design. I'm not trying to make a bundle from it. It's just that this airplane stuff piques my curiosity..."
Since Catto's production schedule was slipping, Paul loaned me his old modified two-blade. Granted, the IVO wasn't much to compare to, but the loaner netted me 15 knots. Same plane, same weight, same DA, same revs, same GPS method.
What we have among us is a crusader for logic and knowledge, that understands physics better than most of us combined! I have no doubt whatsoever that, someday in the not-to-distant future, Paul's work will be the standard by which others' are judged.
There will be bucket-loads of money made on this evolutionary propeller design work, although Paul may not be the guy claiming the credit. It'll probably take much harder-nosed marketing-executive types to change the minds of the typically inert GA afficionado's. Too bad Gulfstream's VP's are all caught up in the jets, I've met some real salesmen in that group.
I'm not saying more than can be witnessed in this thread from the remarks of the supporters as well as the doubters. Count me among the former.
Doubters will call me biased because I already liked the guy, a lot. Even though I was trained at ERAU, Paul was the first person to say to me that "air has no temperature or pressure, only a mass of gaseous particles with kinetic energy yielding an average speed of about .8 Mach". Maybe I'm just a geek, but that statement makes mucho sense to me. You coulda knocked me over with a feather. Not that I would have ever come to it on my own, which may be why many of you find his results so hard to swallow. As you can imagine, I liked him even more after getting 10% quicker.
So as they say, the proof is in the pudding. Is there a "better prop" than the one that makes the most dynamic thrust? Not the way I see it. But what about static thrust? I like that for my swamp-cooler.
Tailwinds Gents,
K.Gregory, ATP -GIV, GV, CFII-SMEL
2nd custodian, '98 Leckenby LNC2 - KHND
(Please pardon that I didn't have the sense to get an RV)
