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From my excruciating review of TCM manuals,
interlaced into T337D performance charts... 75% ROP will give around 150knots IAS @ 13.3gph (ea) x2 = 26.5 gph 65% LOP will give around 140knots IAS @ 10.3gph (ea) x2 = 20.6 gph In the turbo, (non-pressurized) TAS increases linearly @10 knots/5k ft Until you hit 25k (critical altitude), when engine poer starts to dropoff I've never taken it that high, that's a looooong way down if you want to stop! So for example, at 10k ft TAS 75%= 150+10x2=170k @ ROP = 26.5.3gph = 6.4 kn/gal TAS 65%= 140+10x2=160k @ LOP = 20.6gph = 7.7 kn/gal = 20% more range/gal = 6% reduction in TAS speed. ===== Applied to my theoretical 1400 kn trip (each way) from Wash DC to Denver and back... 2800 miles total... 75% = 2800/170k = 16.5 hrs @ 26.5 = 440 gals 65% = 2800i/160k = 17.5 hrs @10.3 gph (ea) =360 gals For ~80 gals extra (roundtrip ~$500?) ...I can cut the round trip time by just ~1 hours...? Questions become, 1) Am I willing to pay $500 to get an hour of my time back? ...nah, I'll just enjoy the cruise for another hour 2) If the airplane costs $200/hour (??), one less hour reduces the extra fuel cost by $200.... CONCLUDE => It does seem to suggest LOP at 65% and enjoy the extra hour of flight time... Thoughts?
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David Wartofsky Potomac Airfield 10300 Glen Way Fort Washington, MD 20744 Last edited by n86121 : 03-08-24 at 11:31 AM. Reason: errors |