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1. 11:05 AM - Blended foil prop (Craymondw@aol.com)
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| Subject: | Blended foil prop |
I had a brief window in our terrible weather yesterday to see what my
performance would be using my new Hartzell "blended foil" prop on my 200 hp
Gl2S FT. I noted the performance at altitudes of 2,000 and 3,000 feet with the
power set at 24.5 inches, 2375 RPM, 50 degrees rich of peak, with an
outside temperature of 50 degrees. My indicated airspeed using my old Hartzell
averaged around 163 mph at those settings at those altitudes. Using my new
blended foil design, I noted indicated airspeed of 185 mph. In the past my
best performance using my previous prop was in the 8,000 to 9,000 feet
altitude range that averaged a 205 mph ground speed. So when this Global
Warming freezing air moves out giving me an opportunity to travel I will report
any differences in cruise speed at those altitudes.
With a previous experimental I owned I noticed that in cruise settings I
had down elevator trim that I felt was causing drag. So when I constructed
our Glasair I changed the angle of attack on my horizontal stabilizer to
around 1/8 positive. I felt having any elevator up trim would be less drag.
And in cruise I did note that my GL2S did require a little up trim
because I could see that the counter balances surfaces would protrude below the
horizontal stab by about 3/8's of an inches. But I noted with the added
thrust using my knew blended foil and higher speed that the elevator required
m
ore down trim causing the tail feathers to become stream lined...yeah!!.
My GL2S driver wife was sitting in the co pilot seat and was very excited
about the increased performance. I did note it takes more to slow the plane
down in the landing pattern using this new prop. Setting my old Hartzell
into high RPM would act like a speed brake, but with this new blended foil
in high RPM our plane now wants to keep on trucking. Another feature is how
much more quiet the prop is. I even removed my head set and noted the cabin
way quieter.
I had around 600 hours on my old prop and found prop shops willing to
pay between $2500 and $3000 as is. Instead I decided to have a reasonably
priced tear down inspection, cleaning and repaint and placed the prop for
sale in Trader Plane for $5,500 and started receiving inquiries and sold it
for the full price in a two issue ad. One woman asked if I would consider
selling just the blades!! $6,000 for a set of good blades would have been
better for me but I turned down the offer.
Harry Delong at the Glasair Company is the blended foil expert and went
to bat for me when YRC freight company screwed up the shipping costs that
have yet to be resolved. To avoid this I suggest having any props shipped to
a business address.
Charles
Raymond
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