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A very wise and experienced Beechcraft Owner & Beech Lister, aka
Old
Bob, has suggested
that flight at best L/D airspeed (or Best Glide in your POH) times a factor of
between 1.1 and 1.2 will yield nearly the optimum in fuel mileage efficiency.
I have found Old Bob's guidance to be true in my
B55. Here are some examples of power settings that I have used for maximum
range/economy NM/gal in my B55:
Usually 8,000' to 12.000'
17" to 19" MP
2100 RPM
7.5 to 8.5 gallons/hour per
engine
Usually in the range of 128 - 138 KIAS
Calculated TAS is usually 150
- 162 KTAS
Here is a calculation from
Dr. Dave Rogers to
help you calculate (L/D)max for your particular weight:
"For the operational weight and the speed for L/Dmax varies
as the square root of the weight ratio, i.e.,
V2(L/D)max = V1(L/D)max*sqrt(W2/W1)"
NEWS FLASH: Recent 700nm Trip
at 9.3 gph/side, 2100 RPM, 19" MP (Full Throttle), 12,000' and OAT 11C I
achieved 172 KTAS! 
NEWS FLASH: Recent 700nm Trip
at 10.3 gph/side, 2250 RPM, 19" MP (Full Throttle), 12,000' and OAT of -10C I
achieved 182 KTAS!
NEWS FLASH: Recent
800nm Trip
at 9.5 gph/side, 2350 RPM, 142KIAS, 30.29" Altimeter, 17" MP (Full Throttle), 15,000' and OAT of -12C I
achieved 178 KTAS!
NEWS FLASH: Recent
800nm Trip
at 10.9 gph/side, 2300 RPM, 159KIAS, 30.17" Altimeter, 21" MP (Full Throttle), 10,000' and OAT of
4C I
achieved 186 KTAS!
Gee Mike, why do you fly so high? Aren't you
burning up a lot more gas to get up there? Thought you'd never ask. Intuitively
it always seemed to make sense for me to fly high to get a higher TAS at a lower
fuel burn, excepting of course when facing mega headwinds up high. Well, here is
a chart created by Beech Lister and fellow Baron driver, Derek D, that shows you
actually SAVE fuel on trips of over 250nm.
You can see why I like the 10,000' to 12,000'
range for my trips of over 500nm. Thanks for the effort on the chart Derek!
Now, while you're in your climb, be sure to
Lean to a Target EGT in the range of 1250F to 1300F!
Here is a LOP Climb scenario that B58 Baron
driver Larry O. uses. It looks like it could be worth 3 gallons
Here is a climb chart and narrative created by
Ward A. for the NA-A36.
The conditions are climb at full power at 120KIAS Cruise at 75% LOP, or full
throttle LOP. Descend at 165KIAS, -500 FPM at what-ever power it take
(constantly adjusting). Above 12k ft, we descent at WOT, and 500fpm at whatever
speed we can get (less than 165KIAS).
As you can see, we're not doing anything unnatural to save fuel. All this is
in comparison to a flight at Sea Level. Note that up to 7k or so, the climb is
free. Above 7k, we save fuel, because we are flying at a slower IAS (read more
efficient) than we are at sea level.
Ward
PS - In a TN - you get more or less free climb to all altitudes. I don't
hesitate to climb to 17.5k, even on a short 200nm flight.
Check out the
EGT Leaning Presentation
from the good folks at
Advanced Pilot Seminars.
This can also help you determine what fuel flow is best to use at high
altitude or high DA situations.
See
Pics of Actual in-flight Power Settings at 10,000'/8.2 gph per side/12C Yielding 162KTAS
HERE
(Click thru 4 pics)
Here are pics of my Exhaust stacks after a 5 hour LOP flight from KATW to KDTO
Read Mike Busch's
#59 Article on Leaning
For grins, here is the actual 75% Power Chart for the B55 from
the 1965 Operating Handbook 28gph!
Give me a break!!! NFW for this CSOB. In the end, it's your
engine and wallet <grins>.
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Long Range Power Settings (Get 15-25% Better Fuel Mileage)