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Al Gietzen wrote:
No, we sure didn't. In fact, I like going faster than my wallet can keep up.
Yeah; me tooJ
In doing some searching for LDmax for the Lancair ES, I read the statement that best economy would be the same as best glide. That makes sense to me. Probably close enough for our purposes. What say you?
I found my data. I think it may be just a bit more complicated. Best glide will likely give you the lowest fuel burn rate (gph); but since you’re going fewer miles in an hour; it’s not the best mpg. My best glide speed is about 90 kts; but my best mpg is about 130kts - quite flat from about 140 – 120 kts. The burn rate was continuing to go down at 110 kts; which was as far as I took data.
So minimum trip cost is at max MPG; if you consider your time as free. But my plane seems to have a ‘sweet’ spot at 5500-5700 rpm, and at 10,500 I can go about 170 KTAS at a tad over 10 gph, so that’s what I do. I could slow to 130 Kts and burn a tad under 7.0 gph; but would I be happyJ?
Al
And just one more factor to keep everyone confused or the conversation going, whichever way you want to take it. The M in that MPG is the is the miles of air your crossing...not the miles of ground. With a tailwind, you'll want to pull the throttle back a little more and let Mother Nature do some of the work of getting you to the destination. If you've got a headwind, you're constantly being pushed backwards. Every extra second in the air requires more energy to get back the headway that was lost, so it makes sense to add some power and force your way through it quickly.
How much to add or back off? Don't ask me. There some computer programmers at the major airlines making really good bank trying to figure that one out 8*)
(It also might make sense to fly at a higher altitude with more of a headwind, because the thinner air offers less drag. The solution to that one is also left as an exercise for the reader 8*)
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