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1. 08:16 AM - (no subject) (LesDrag@AOL.COM)
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--> TeamGrumman-List message posted by: LesDrag@aol.com
Hi All,
IMHO, Andy has it right.
On the "Lycoming 360 propeller" page of my website, _www.lessdrag.com_
(http://www.lessdrag.com/) , I have the data taken on four different CS propellers
in an RV-6A with a Lycoming O-360 180 hp engine. When you look at the
airspeed with RPM for all four CS propellers, there is NO speed increase in cruise
at full throttle above 2500 RPM. In fact, there is usually a speed decrease
at 2700 RPM. On all 4 propellers.
What is significant is the reduction in fuel flow at 2300 RPM and full
throttle with little loss in cruise speed. In fact, the 3 blade MT Propeller
exhibited a basically flat airspeed at 12,500' with full throttle from 2700 RPM
to 2300 RPM. Only the fuel flow changed.
BTW, Someone previously mentioned the "old" airfoil used on the MT Propeller
for the Tiger. This -17 blade actually consists of a smooth transition
through five airfoils from blade root to blade tip.
It's nice that Hartzell is using this "old" technology with their new
"blended airfoil" propeller. :-)
Regards,
Jim Ayers
Less Drag Products, Inc. - An MT Propeller distributor
(805) 795-5377
PS The other problem mentioned. Cost. I can help to reduce the expense.
In a message dated 03/26/2005 7:53:44 PM Pacific Standard Time,
loanshark@msn.com writes:
Increasing the RPM restriction would defeat the purpose of the prop. The
power translates to more pitch giving you 2700 RPM speed, or may be 2 knots
faster at 2500 RPMS. Increasing the MT prop to 2700 gives you a flatter
pitch, no extra speed, more engine ware, less efficiency, among other things
I will leave to the experts. Short field take offs? You are getting 2500
static VS. the traditional Tiger 2150. My experience is about a 30%
reduction in feet over an obstacles. (Please lets not start this up, but I
am a definite believer in 1/3 flaps short fields.) The MT POH I believe also
reflects this, but is in meters and I haven't the time or desire to convert
the testing. VY? about the same. Quiet? like riding in a car, with no or
little vibration thus making most everything in the aircraft live longer.
Would I do it again? ONLY Probably because I go in and out of a short strip
regularly, but if were less expensive, it would be worth it for many more
reasons.
Andy Jensen
tigers 1975 models to 2002: 1600 hrs (200 on mt prop)
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