Author: "brywd" <brywd@...> Time: Mon Oct 21, 2002 8:10 pm PDT Link
Good evening everybody,
Just sitting here thinking about propeller choices for my airplane and
thought I'd put some thoughts/questions out to the rest of you. Today
I spent some time with Ken S. on the phone and pretty much decided on
the MT like the one on the demonstrator. Quiet, smooth and good looks
to boot, but at quite a price. After finishing the conversation with
Ken I called a dealer that will receive the prop and discussed
overhaul prices for the three blade MT vs. the two blade Hartzell and
they are almost identical. I was told that the MT is prone to more
leaks that the Hartzell which now has me second guessing my decision.
They also stated that if I keep the airplane outside the MT will not
hold up as well, especially after it has a ding or two in it that will
let moisture at the wood inside. The prop shop strongly endorsed the
Hartzell. Now with that to digest I got home from work tonight and
the new RVator was in the mail. Yes, you guessed it, there is an
article on props this issue. I turns out Van's and Hartzell did some
testing on Dilbert the RV-8 with the fadec.The prop now has a wider
operating limitation than without the fadec system. Then they took it
off and installed one lightspeed electronic ignition on the right side
and re-ran the tests. Just this caused another prop restriction. Now
the placard for no continous power between 2000 and 2250 RPM was
added to with nothing over 2600 except on takeoff. I guess what I'm
getting at is just picking an engine and prop to use can be fatal if
we screw up. I've thought of having high compression pistons put into
the engine to kick up power slightly, or flow porting, and electronic
ignition, etc., but it looks like the smart thing is a stock engine
with a known and tested prop combination. What do you all think?
Anyway, all input on the MT vs. Hartzell would be greatly appreciated.
Regards,
Bryan Wood
Author: "Sam Benjamin" <sambenjamin@...> Time: Mon Oct 21, 2002 9:42 pm PDT Link
I'm happy with my 160 horse fixed pitch (80") propeller. Constant speed props add weight to the aircraft and do not appreciably improve performance. Smooth air crusing in the yellow arc doesn't lend itself to comfortable flying in turbulance.
Sam.
----- Original Message -----
From: brywd
To: RV-9A@yahoogroups.com
Sent: Monday, October 21, 2002 11:10 PM
Subject: [RV-9A] Propeller choices
Good evening everybody,
Just sitting here thinking about propeller choices for my airplane and
thought I'd put some thoughts/questions out to the rest of you. Today
I spent some time with Ken S. on the phone and pretty much decided on
the MT like the one on the demonstrator. Quiet, smooth and good looks
to boot, but at quite a price. After finishing the conversation with
Ken I called a dealer that will receive the prop and discussed
overhaul prices for the three blade MT vs. the two blade Hartzell and
they are almost identical. I was told that the MT is prone to more
leaks that the Hartzell which now has me second guessing my decision.
They also stated that if I keep the airplane outside the MT will not
hold up as well, especially after it has a ding or two in it that will
let moisture at the wood inside. The prop shop strongly endorsed the
Hartzell. Now with that to digest I got home from work tonight and
the new RVator was in the mail. Yes, you guessed it, there is an
article on props this issue. I turns out Van's and Hartzell did some
testing on Dilbert the RV-8 with the fadec.The prop now has a wider
operating limitation than without the fadec system. Then they took it
off and installed one lightspeed electronic ignition on the right side
and re-ran the tests. Just this caused another prop restriction. Now
the placard for no continous power between 2000 and 2250 RPM was
added to with nothing over 2600 except on takeoff. I guess what I'm
getting at is just picking an engine and prop to use can be fatal if
we screw up. I've thought of having high compression pistons put into
the engine to kick up power slightly, or flow porting, and electronic
ignition, etc., but it looks like the smart thing is a stock engine
with a known and tested prop combination. What do you all think?
Anyway, all input on the MT vs. Hartzell would be greatly appreciated.
Regards,
Bryan Wood
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Author: "sam_mourning" <sam.mourning@...> Time: Tue Oct 22, 2002 8:12 am PDT Link
Hi Bryan.
I too, thought that article in the RVAtor was pretty interesting
since I've also been thinking about props.
I've been building my 9A since April of this year and researched it
for almost a year before that.
It looks to me like the prop/engine combination question is one of
those areas where there's more to it than meets the eye. For me,
Yes, I'm building an "experimental" aircraft but that doesn't
necessarily
mean I "have to" experiment in areas where I don't have the
engineering skills to make a fully informed decision.
For my money (and life) a well known, proven combination will be the
smartest way to go.
Sam Mourning
--- In RV-9A@y..., "brywd" <brywd@p...> wrote:
> Good evening everybody,
>
> Just sitting here thinking about propeller choices for my airplane
<SNIP>
electronic
> ignition, etc., but it looks like the smart thing is a stock engine
> with a known and tested prop combination. What do you all think?
> Anyway, all input on the MT vs. Hartzell would be greatly
appreciated.
>
> Regards,
> Bryan Wood
Author: "rv9builder" <mschrimmer@...> Time: Tue Oct 22, 2002 9:02 pm PDT Link
--- In RV-9A@y..., "Sam Benjamin" <sambenjamin@c...> wrote:
> I'm happy with my 160 horse fixed pitch (80") propeller.
Constant speed props add weight to the aircraft and do not
appreciably improve performance. Smooth air crusing in the
yellow arc doesn't lend itself to comfortable flying in turbulance.
> Sam.
Sam,
I'm considering a Sensenich prop and hope you can answer a
few questions . . .
Why did you decide to go with an 80" prop instead of the 79"
recommended by Van's for the RV-9A? What kind of climb
performance are you getting on takeoff? Is it hard to slow down
from cruise speed to flap speed?
Thanks,
Mark Schrimmer
Author: "Sam Benjamin" <sambenjamin@...> Time: Wed Oct 23, 2002 3:02 am PDT Link
Mark,
I went with the 80" pitch becouse I didn't think I needed the capability of taking from a field shorter than 500ft, but I do like to cruise fast. The sensenich prop is restricted to less than 2600 Rpm. With the 80" pitch I can run full throttle without exceeding 2600 rpm. I am truing out at about 180 MPH. My initial climb is over 1000 FPM. Any plane that flys fast is going to be hard to slow down. After a short time in the plane you will learn to plan ahead and you will have no trouble getting it slowed down.
Sam
I'm considering a Sensenich prop and hope you can answer a
few questions . . .
Why did you decide to go with an 80" prop instead of the 79"
recommended by Van's for the RV-9A? What kind of climb
performance are you getting on takeoff? Is it hard to slow down
from cruise speed to flap speed?
Thanks,
Mark Schrimmer
Yahoo! Groups Sponsor
ADVERTISEMENT
To unsubscribe from this group, send an email to:
RV-9A-unsubscribe@egroups.com
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