OK, OK, rub it in, but before you guys get carried away, consider the
following:
The prop limitation was always my only reservation about using the higher
ratio. I must emphasize that in order for this to work, the prop must
not only be long but has to have a good profile as far down toward the root as
possible with the MUCH higher pitch. I worked with Clark at Perf. Props
and emphasized this. It required a thicker than standard hub to get
close to what was needed.
If you don't do these things, all you get is significantly higher
rpm, less performance, higher fuel burn and higher wear. Look at
the numbers from previous users of the 2.85 drive.
Did I mention the three spinners, various spinner bulkheads, prop bolts
that were now too short and other various things that went
wrong during the effort to make this work right?
Tracy
As always the difference is in the attention to details
that affect the operation. Sound like you have the right combination of
prop and gearbox ratio to overcome those limitations. I wonder if
a 3 bladed prop might not be the answer for those prop length
challenged.
You mentioned seeing 7050 rpm - if at 1000 MSL
and 75F OAT if you were running WOT and rich, that appears to give you right
at 200HP out of your engine. I don't suppose you noticed your fuel burn
rate? I would think it would be around 18 GPH. My calculations indicate
around 18.5 gph.
Ed Anderson