Today's Message Index:
----------------------
1. 02:41 AM - Re: Electrical Question (FLYaDIVE@aol.com)
2. 05:34 AM - Electric Constant Speed Prop (James Grieco)
3. 06:08 AM - Re: Electric Constant Speed Prop (flyv35b)
4. 06:57 AM - Re: Electric Constant Speed Prop (Gil Alexander)
5. 08:28 AM - Re: Electrical Question (Aucountry@aol.com)
6. 08:30 AM - Re: Electric Constant Speed Prop (Aucountry@aol.com)
7. 08:31 AM - Re: Electric Constant Speed Prop (Aucountry@aol.com)
8. 10:43 AM - Re: Electric Constant Speed Prop (Ron Levy)
9. 10:29 PM - Re: Electric Constant Speed Prop (Aucountry@aol.com)
Message 1
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| Subject: | Re: Electrical Question |
--> TeamGrumman-List message posted by: FLYaDIVE@aol.com
In a message dated 9/29/03 9:11:17 AM Eastern Daylight Time,
steven.jackson14@adelphia.net writes:
> Whoops! My bad. I guess I couldn't think that far out of the box. That
> sounds like a smart idea...
>
> Steve
>
>
> Gary wrote:
>
> I would NEVER, EVER use an avionics master. The switch you see is the
> switch to select electrical bus power or battery power for the
> Ultra-Vision=20lights
> used in the eyebrow.
>
> Gary
=================
Oooooooooooooo Shame on you Gary!
Why wasn't the switch labeled? Whoops, Look who is talking ... Look at the
Pot calling the Kettle black. I just remembered I have two unlabeled switches.
BROTHER! It's time to get out the Brother Label Maker ... Just can't find
the correct label material for the job. Black background and White letters.
Barry
"Chop'd Liver"
Message 2
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| Subject: | Electric Constant Speed Prop |
TeamGrumman <teamgrumman-list@matronics.com>
--> TeamGrumman-List message posted by: James Grieco <jamesgrieco@yahoo.com>
I emailed a request to MT props about performance specs on the
constant speed prop. I am afraid they shot themselves in the
foot on this one.
my email:
> Where on your web site can one find the before and after
performance specs.
> I would presume that there should be an update to the Pilot
Operating
> Handbook for take-off performance, climb rate, etc.
> Thanks in advance
their response:
Hello,
the performance data is not yet available online.
For every STC exists of course an update to the POH.
Our chief engineer Mr. Josef Eberl can give you more
detailed information about the performance differences.
However, the main purpose of the Grumman Tiger STC was
noise reduction rather than enhancing the performance
a lot. Versus the fixed pitch propeller, which is just
designed for one flight condition (climb or cruise) or
a compromise, the electric constant speed propeller
offers maximum performance in all flight conditions
(take-off, climb and cruise). The diameter of the
constant speed propeller is in this case much smaller
than the original fixed pitch propeller (70.8" vs 76")
and the max. continous RPM has been reduced to 2500, so
that there is finally no big performance increase although
a third blade has been added. The advantages of the small
prop diameter is the noise reduction: 5.7 dB(A) measured
in accordance with ICAO chapter X and a lot more ground
clearance. The vibration dampening material of our blade
design and the much lower inertia provides a much smoother
run. Any exact performance figures will be supplied by
Mr. Josef Eberl (Josef.Eberl@mt-propeller.com), who is
presently on a business trip, but will be back in the
office next week.
Best Regards
Michael Muehlbauer
mailto:support@mt-propeller.com
__________________________________
Message 3
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| Subject: | Re: Electric Constant Speed Prop |
--> TeamGrumman-List message posted by: "flyv35b" <flyv35b@juno.com>
I think so too. With that kind of diameter and rpm reduction I would be
surprised if the cruise performance was worse than with the 76 in.
Sensenich. The actual performance comparison data would be quite
interesting.
Cliff A&P/IA
----- Original Message -----
From: "James Grieco" <jamesgrieco@yahoo.com>
<teamgrumman-list@matronics.com>
Subject: TeamGrumman-List: Electric Constant Speed Prop
> --> TeamGrumman-List message posted by: James Grieco
<jamesgrieco@yahoo.com>
>
> I emailed a request to MT props about performance specs on the
> constant speed prop. I am afraid they shot themselves in the
> foot on this one.
>
>
> my email:
> > Where on your web site can one find the before and after
> performance specs.
> > I would presume that there should be an update to the Pilot
> Operating
> > Handbook for take-off performance, climb rate, etc.
>
> > Thanks in advance
>
> their response:
>
> Hello,
>
> the performance data is not yet available online.
> For every STC exists of course an update to the POH.
> Our chief engineer Mr. Josef Eberl can give you more
> detailed information about the performance differences.
>
> However, the main purpose of the Grumman Tiger STC was
> noise reduction rather than enhancing the performance
> a lot. Versus the fixed pitch propeller, which is just
> designed for one flight condition (climb or cruise) or
> a compromise, the electric constant speed propeller
> offers maximum performance in all flight conditions
> (take-off, climb and cruise). The diameter of the
> constant speed propeller is in this case much smaller
> than the original fixed pitch propeller (70.8" vs 76")
> and the max. continous RPM has been reduced to 2500, so
> that there is finally no big performance increase although
> a third blade has been added. The advantages of the small
> prop diameter is the noise reduction: 5.7 dB(A) measured
> in accordance with ICAO chapter X and a lot more ground
> clearance. The vibration dampening material of our blade
> design and the much lower inertia provides a much smoother
> run. Any exact performance figures will be supplied by
> Mr. Josef Eberl (Josef.Eberl@mt-propeller.com), who is
> presently on a business trip, but will be back in the
> office next week.
>
> Best Regards
> Michael Muehlbauer
> mailto:support@mt-propeller.com
>
>
> __________________________________
>
>
Message 4
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| Subject: | Re: Electric Constant Speed Prop |
--> TeamGrumman-List message posted by: Gil Alexander <gilalex@earthlink.net>
My Tiger certainly doesn't get 2500 rpm in climb, so wouldn't the extra HP
at more RPMs give a better climb rate, even if you are limited to 2500 rpm?
gil in Tucson
At 05:34 AM 9/30/2003 -0700, you wrote:
>--> TeamGrumman-List message posted by: James Grieco <jamesgrieco@yahoo.com>
>
>I emailed a request to MT props about performance specs on the
>constant speed prop. I am afraid they shot themselves in the
>foot on this one.
>
>
>my email:
> > Where on your web site can one find the before and after
>performance specs.
> > I would presume that there should be an update to the Pilot
>Operating
> > Handbook for take-off performance, climb rate, etc.
>
> > Thanks in advance
>
>their response:
>
>Hello,
>
>the performance data is not yet available online.
>For every STC exists of course an update to the POH.
>Our chief engineer Mr. Josef Eberl can give you more
>detailed information about the performance differences.
>
>However, the main purpose of the Grumman Tiger STC was
>noise reduction rather than enhancing the performance
>a lot. Versus the fixed pitch propeller, which is just
>designed for one flight condition (climb or cruise) or
>a compromise, the electric constant speed propeller
>offers maximum performance in all flight conditions
>(take-off, climb and cruise). The diameter of the
>constant speed propeller is in this case much smaller
>than the original fixed pitch propeller (70.8" vs 76")
>and the max. continous RPM has been reduced to 2500, so
>that there is finally no big performance increase although
>a third blade has been added. The advantages of the small
>prop diameter is the noise reduction: 5.7 dB(A) measured
>in accordance with ICAO chapter X and a lot more ground
>clearance. The vibration dampening material of our blade
>design and the much lower inertia provides a much smoother
>run. Any exact performance figures will be supplied by
>Mr. Josef Eberl (Josef.Eberl@mt-propeller.com), who is
>presently on a business trip, but will be back in the
>office next week.
>
>Best Regards
>Michael Muehlbauer
>mailto:support@mt-propeller.com
>
>
>__________________________________
>
>
77 Tiger, N28478, at 57AZ
Message 5
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| Subject: | Re: Electrical Question |
--> TeamGrumman-List message posted by: Aucountry@aol.com
In a message dated 09/30/03 02:42:08 AM, FLYaDIVE@aol.com writes:
> Why wasn't the switch labeled?=A0 Whoops, Look who is talking ... Look at=20the
> Pot calling the Kettle black.=A0 I just remembered I have two unlabeled
> switches.
> BROTHER!=A0 It's time to get out the Brother Label Maker ... Just can't find
> the correct label material for the job.=A0 Black background and White letters.
>
The picture was taken right after the panel was finished. And, it was
labeled. The Ultra Vision comes with labels. The other switches weren't=20labeled
though.
Message 6
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| Subject: | Re: Electric Constant Speed Prop |
--> TeamGrumman-List message posted by: Aucountry@aol.com
In a message dated 09/30/03 05:34:40 AM, jamesgrieco@yahoo.com writes:
> and the max. continous RPM has been reduced to 2500, so
>
Say what? I can't think of anyone who would willingly give up the
horsepower difference between 2500 and 2700 rpm just so the plane is quieter.
What
the hell are they thinking?
Message 7
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| Subject: | Re: Electric Constant Speed Prop |
--> TeamGrumman-List message posted by: Aucountry@aol.com
In a message dated 09/30/03 06:58:22 AM, gilalex@earthlink.net writes:
> My Tiger certainly doesn't get 2500 rpm in climb, so wouldn't the extra HP
> at more RPMs give a better climb rate, even if you are limited to 2500 rpm?
>
>=A0 gil in Tucson
>
no
Message 8
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| Subject: | Re: Electric Constant Speed Prop |
--> TeamGrumman-List message posted by: Ron Levy <rblevy@mindspring.com>
--> TeamGrumman-List message posted by: Gil Alexander <gilalex@earthlink.net>
>My Tiger certainly doesn't get 2500 rpm in climb, so wouldn't the extra HP
>at more RPMs give a better climb rate, even if you are limited to 2500 rpm?
The 2500 RPM limit is for CONTINUOUS operation, not takeoff and climb.
In fact, you'll have MORE power for takeoff, as you'll be turning a full 2700 RPM
instead of the 2300-2400 you're currently seeing, thus obtaining the engine's
full 180 HP at sea level compared to 155 HP or so you're currently extracting
in that situation. 25 extra HP means about 340 fpm more climb rate. Same
for climb, where few if any Tigers turn over 2500 RPM at normal climb speeds,
even if you pull back to 2500 for cruise climb with the MT prop.
For cruise, you aren't turning more than 2500 RPM at 75% with a stock prop until
you get high enough that you can go full throttle with the MT prop at 2500 RPM
without exceeding the MP limit for that RPM (26 inches or so, I think -- don't
have the engine operator's manual handy). However, above 10,000 or so, where
you run into the RPM red line with a fixed pitch prop, the MT prop allows
full throttle operation at 2500 RPM, getting more power out of the engine.
Thus, with the MT prop, I'd expect better takeoff and climb performance, similar
cruise speeds below 10,000 or so, and better cruise speed above 10,000.
And I think David Fletcher is still looking for a guinea pig for the MT prop.
I think he was offering free installation to the first customer to buy the prop
from him.
Ron
Message 9
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| Subject: | Re: Electric Constant Speed Prop |
--> TeamGrumman-List message posted by: Aucountry@aol.com
In a message dated 09/30/03 06:58:22 AM, gilalex@earthlink.net writes:
> My Tiger certainly doesn't get 2500 rpm in climb, so wouldn't the extra HP
> at more RPMs give a better climb rate, even if you are limited to 2500 rpm?
>
>=A0 gil in Tucson
>
My initial response was "no"
I'm a victim of speed reading errors and too much going on to look at the
entire email carefully.
When I read the technical description from MT Propellers, I completely missed
the line
" the electric constant speed propeller offers maximum performance in all
flight conditions
(take-off, climb and cruise)."
And, when I read Gil's question, I understood it that he was asking if his
engine with an MT Prop at 2500 rpm would be producing more horsepower at 2500
than his engine during takeoff at 2500 rpm.
My subsequent response had to do with giving up 200 rpm in cruise.
Personally, I never (or shall I say, rarely,) fly at less than full throttle and
2700
rpm when possible. My Cheetah would turn 2700 at 10,000 feet. So, when
someone says that I would be limited to 2500 rpm, I start thinking I have to be
going slower. I have to admit, I've never flown a plane with a constant speed
prop. I have no idea what to expect with a CS prop.
The questions then become: What is the prop pitch on the MT Prop when set at
2500 rpm for cruise?
and
How does that pitch compare to a Sensenich at, say, a 63 inch pitch?
If the MT prop gives a better climb rate and is slower in cruise, there would
have to be a big increase fuel economy before it makes sense to cough up
$13,000 (that's the number I remember).
If the MT prop makes a pitch that makes up for the 200 rpm loss (assuming the
engine is strong enough to turn 2500 at course pitch) and there is no loss in
cruise speed, then, ... it might make sense.
Gary
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