Mike Stirewalt wrote: >....as a pilot I do wonder why anyone would ever fly around (except for >the occasions mentioned above) using partial throttle.
Peter's got it right regarding efficiency. On long cross country flights, I'm usually going to OSH or SNF, and I plan for 40 mpg @160 mph TAS. Part of the equation is the number of fuel stops. When you're flying at 10,000-12,000 feet (if the winds are favorable), it takes a long time to climb back to that kind of altitude, not to mention the time killed on the ground when I could be getting where I want to go. Minimizing fuel burn minimizes my fuel stops, with the bonus of having to buy less 100LL when I do land. Fewer stops also minimizes what is often the most dangerous phase of a flight, the climbout at full power. I've got three broken cranks to prove that one. The vast majority of the time, I am turning a sedate 3050 rpm behind the Corvair, even though 3600 is what I can get with the 54x58...4000 rpm with the 54x54 (Sensenich numbers). I'll confess to flying at something in the neighborhood of 55% power most of the time I'm flying, even at high altitude, despite my undeserved reputation of being a hotdog and beating my Corvairs to death. I've played with throttle settings a lot while flying, and with the fuel totalizer I can keep a pretty good eye on it, so I have a pretty good feel for where the economy is and where it isn't...WOT. Maybe I'm just a cheapskate, but I hate to blow fuel through the tailpipe knowing that the plane is just not going to go proportionally faster with more power out front....it's that drag thing. This is off the subject, but let me throw this out there. When I get near my destination I plan for a 800 ft/min descent rate, rather than the more customary 500 ft/min. That's because I've done glide testing that proves my plane with no power descends at about 680 ft/min. If the engine craps out a few miles out from the airport, you're not going to get there, and you don't have enough altitude to get anywhere else either. I come in high and slip like crazy if I need to, but I'm not going to get caught short of the runway wishing I'd been thinking a little further ahead... Mark Langford ML at N56ML.com website at http://www.N56ML.com --------------------------------------------------------
