Czech Mate

[Leo]

Re: Czech Mate

Hello Deepsky! I have #8 in the que (you said it would be near impossible for me, my son agrees, so, a challenge). Cobra ii is almost finished, then #8 then Vicki's purple mustang.

[RichH]

Re: Czech Mate

Let me expand on my reply. When a propeller that is too large is fitted to an airplane the blades are shortened with a straight cut because it is simple and costs less not for efficiency. Attached is a photo of a CNC profiled blade on Precious Metal which gave a 56 MPH increase in speed.

I don't buy that. PM went just as fast in 1988 with stock blades. They were basing the "56MPH" speed increase vs the previous year... when they were limping along with an engine where the cam tower broke and was lifting off. I don't disagree that there was a difference. I highly disagree there was that degree of difference with the profiled blades alone...

[Plane Nuts]

Re: Czech Mate

I don't buy that. PM went just as fast in 1988 with stock blades. They were basing the "56MPH" speed increase vs the previous year... when they were limping along with an engine where the cam tower broke and was lifting off. I don't disagree that there was a difference. I highly disagree there was that degree of difference with the profiled blades alone...

My statement is what Thom Richards told me at NCAR that year. I was not aware of the mechanical issue the previous year.

[RAD2LTR]

Re: Czech Mate

I don't buy that. PM went just as fast in 1988 with stock blades. They were basing the "56MPH" speed increase vs the previous year... when they were limping along with an engine where the cam tower broke and was lifting off. I don't disagree that there was a difference. I highly disagree there was that degree of difference with the profiled blades alone...

Yes, the Whittingtons went 465 with a 10/10ths race Griffon back '88. The 56mph gain was found when they were running a tired Miss Budweiser former race engine that was thrashed together using what parts they had handy. It was hardly a fresh engine with top end parts in it. Compared to a full race prepped engine, it was closer to a stock Griffon than a race prepped one. They were way down on power compared to what the Whittingtons were running in '88, yet they went the same speed.

The prop blade redesign for PM was proposed well before Thom bought it. I believe it was Steve Fossett that started looking at ways to make PM faster for a transcontinental record attempt, and it was his research into things that paved the way for PM to become what it became. This info comes from a former team member who worked for Fossett at the time.

Will

[wingman]

Re: Czech Mate

Not only a full race Griffon, but Don was reportedly running REALLY high rpms -- far beyond anything Thom or anybody else has attempted since. That 1988 speed just cannot be compared to Thom's speed -- Thom landed the airplane on its wheels...

Neal