I think its time to post my performance tips for Musketeers again. #1: Reduce the load. Don’t tanker fuel. (really now, who NEEDS 60 gal of
fuel for their mission?) Fly with fuel to the tabs for most flights and
save the weight of a passenger. Less weight means faster acceleration,
slower stall speed and lower T/O and landing distances.
#2: Load the CG to a more aft position. Work the W&B problems for your
aircraft. Note that 2 pilots in the front seats, especially at 200+ pounds
each puts you at or in front of the forward CG limit! Carefully compute
the load needed in the baggage compartment to shift the CG aft to within 1″
of the aft limit. The speed gains can be quite impressive. Does YOUR 150
HP Musketeer cruise at 125 mph? After confirming that your plane really
DOES go a lot faster properly ballasted, consider changing the starter to
the light weight type, such as the Sky-Tec 149LS, and also on models that
don’t yet have a ballast weight in the tail, consider finding the 22# lead
weight out of a salvage yard A23-19 and having it installed on the most
rear bulkhead to help you load the CG aft. These are never damaged in the
crash and have no resale value, so they will be CHEAP. Note that it is
possible to load some models too far aft with a lot of weight in the back
seat and baggage area if you have the light starter and ballast weight
installed, so one MUST have accurate W&B info and USE it.
#3″ Fly the mission profile that lets your plane use some “free” airspeed
from the lower density of the atmosphere at altitude. True Air Speed rises
at about 2% for each 1000′ of DENSITY ALTITUDE. Take off and leave the
throttle firewalled and climb directly (ATC permitting) to cruise altitude
at Vy or perhaps Vy+10 to see over the nose better. Let the lower density
of the air control your manifold pressure, rather than using the throttle
to induce “pumping losses” in the engine. This means cruising at a Density
Altitude of ~ 7500′ -8000′. Lean as needed, never below 3500′ except at
part throttle. If you have an EGT gauge, only lean in climb enough to
start the temps to rise, not to peak. You want the cooling of the richer
mixture, and best power is richer than peak by 125-150 degrees. On
descent, just roll the trim wheel for a 500 fpm descent and retard throttle
as needed to stay below the tach redline. This will give you the best time
UP to altitude and help gain back some of the time lost in climb on
descent. Musketeers will do 140 mph on the way down at 500 fpm and cruise
power. And with 500 fpm descent from 7500′, you’ll need 13 minutes to
pattern altitude and be running a much higher GS. 13 minutes at 140 mph is
30 miles out that you have to push over!
Other than the cost of the light starter, these are essentially FREE
performance tips. Read the Lycoming Engine Operator’s Handbook ($19 direct
from Lycoming) for your engine and learn that your instructor didn’t
explain engine operations very well. 2400 rpm is NOT “cruise power”,
except at some very low altitude.
Musketeers are not THAT much slower than 172s and Warriors.
Bob Steward, A&P IA
Birmingham, AL