Hi Greg, Ed Anderson gave you numbers that closely parallel what I have seen. I tend to cruise at higher altitudes which partly accounts for my slightly lower fuel burn. I'm just now starting on my Renesis evaluation. First I wanted to compare it to the earlier rotary (89 vintage) so I installed the RD-1C 2.85 : 1 drive and larger prop (intended for the Renesis). Things are different enough that it will take at least 20 hours to evaluate. I'll be posting detailed reports on the website. On the second flight test of this configuration I had planned to do a maximum performance takeoff to see how it compared. I was fully aware that the P-factor would be opposite (prop turns right instead of left) but I was unprepared for the magnitude of it. With full right rudder the plane was still veering left. Things happened too quickly for me to be exactly sure of what happened next but I think when the tail wheel lifted off, the plane turned sharply to the left and I was certain that I was going to crash into the fence that borders the runway. No one was more surprised than I when the RV-4 lifted off and cleared the fence (barely!). There were lots more interesting differences (most of them good) but it will take several pages and more time than I have right now to explain them. My first recommendation when using the -C drive and a big prop is Feed in power gradually on takeoff until rudder is fully effective. A bit of right offset in the engine mount might also be in order (mine has none). Tracy ----- Original Message ----- From: Greg Fuess Sent: Sunday, March 21, 2004 1:22 AM To: Rotary motors in aircraft Subject: [FlyRotary] Fuel Consumption Questions Hi Fellow Rotor heads,
I am getting very close to starting construction of an RV-7 (much closer
than last year when I said this! - should start in 8~10 weeks) and very
interested in the potential for the Renesis engine in this application
(can't wait for Tracy to get his installed so we can read the performance
reports). I do have one question that is difficult for me to get my arms
around. What kind of fuel burn are you guys experiencing that are flying
your 13Bs? Turbocharged 13Bs? -at various power settings and altitudes? Is
there a data reference site anywhere that could provide this information?
Ed Anderson's Rotary Power vs. 2-3-2 Cooling BTU calculation spreadsheet
indicated 12.4 to 14.9 gph at 5k to 6k rpm (all for 1,500' alt). This seems
not to compare well to the lyconosaurus published consumption rates for a
180 hp engine, though I have read elsewhere on the internet that the rotary
consumption should be similar. Am I misreading or misusing Ed's
spreadsheet, or should I get used to the higher consumption rate? Are the
Lycoming consumption rates bogus?
I am something of a lurker here, but as I get closer to the "date", I am
getting more and more detail conscientious. Appreciate any and all
thoughts.
Best Regards,
Greg Fuess
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