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Just excellent data!
So your 42 lbs mass is being
accellerated at 80% available (rpm) power, your prop producing 220 lb. f.
initial thrust, for 5.24 ft/sec/sec accelleration ... without rpm increase to 62
mph.
Let's see, how can this be
looked at for prop efficiency (n)? ... the ave. torque for 99HP
@ 2230 rpm would be about 240 lb.ft., and with equal blade spanwise
loading, about an approximate load center radius of 1.25 ft. or less, or
about 190 lbs. of torqueing force (drag)there, assuming the drag is coming
from the same radii as the thrust-lift... and the prop produces thrust of
220 lb. f (like, lift)... actually much more but some is swirled into
anti-torque...
How to think of this as
efficiency? Is there a formula for that?
Anyway, this info is reassuring
and I shall proceed, and
will publish the results when I finally get flying....
Tested my 1990 wing tanks for
leaks last week, and one seemed to; so took off the drain valves and the
gascaps, and found old O-rings on the valve and one on the bolt throuogh
the cap, and cleaned all up and replaced the O-rings, and (VERY tankfully) that
fixed it. I'll try the silicon grease on the cap's lever base, as it had a
lot of friction.
Many thanks, Paul.
----- Original Message -----
Sent: Sunday, September 30, 2007 10:21
PM
Subject: [LML] Static Thrust
PSL 30.06",
PSFC 29.72", MAP 28.25 Avg", OAT 15C,
2230 RPM, Thrust 220 LB, HP=125
X2230/2800X28.25"/28.4"*=99HP.
ELIPPSE three-blade prop. 220 lb/(1350 lb/32.17) = 5.24
ft/sec^2 initial acceleration= 17.3 sec to 62 mph without rpm increase and 784
ft.
* 28.4" is the typical MAP at SL conditions, a 1.5" drop
across the carburetor.
There I was,sight-seeing around my home, wondering why
my wing fuel caps were so hard to close when I fueled it up, when I looked out
at my right wing. There was the cap sticking up 1/4"! Looking to the left,
same thing. I slowed down and returned to SMX. 'Turns out the cam
lever had so much friction it really wasn't seating and pulling the
cone up into the rubber donut. I applied silicon grease at the base of the cam
lever and between the donut and cone. 'Locking just fine
now!
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