Today's Message Index:
----------------------
1. 07:07 AM - Re: GSC GTA In-Flight on my Series 3 (Jeremy Casey)
2. 08:31 AM - GSC GTA In-Flight on my Series 3 (Fox5flyer)
3. 09:48 AM - Re: GSC GTA In-Flight on my Series 3 (Andrew Matthaey)
4. 10:07 AM - Re: GSC GTA In-Flight on my Series 3 (Aerobatics@aol.com)
Message 1
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| Subject: | GSC GTA In-Flight on my Series 3 |
--> Kitfox-List message posted by: "Jeremy Casey" <n79rt@kilocharlie.us>
Deke, I usually (almost always, actually) cruise my 582 at 5200 - I get
low
fuel burn and decent airspeed (63ish). I even flew all the 11 hrs to
Virginia at 5200! But let's say I were to cruies at 6300 tomorrow - and
I
get 80 mph...IF were to have an in-flight prop, and I set the throttle
at
6300, then dialed in the pitch to bring it down to 5200 or so, would I
see
that SAME 80 mph? Because all I'm doing is slowing down the
motor...nothing
more, correct?!
Andrew
<snip>
Andrew,
I want to throw in my $.02 worth...disclaimer...been about 3 years since
I flew 2 stroke...and then was a 503, not 582...but principles are the
same...also was not an "in-flight" adjustable prop, just ground
adjustable.
Increasing prop pitch (or said a different way, engine loading) in large
increments would cause EGT's to go crazy, as stated already I believe,
using the prop pitch to pull down the RPM is just reducing the amount of
air but not the amount of fuel (richer). Going the other way could
cause major problems, and should be carefully thought through.
Similar but separate comment. Friend that has a Murphy Renegade tried
the inflight adjustable IVO and got a little better takeoff/climb and a
couple mph better cruise (draggy biplane isn't going to fast no matter
how much horsepower...) Later was loaned a 2 blade Warp Drive to try
and set to a fixed pitch, it out performed the adjustable IVO in all
respects...different airframe, so your results may be different, but the
IVO's are just not go fast props.
Jeremy Casey
jeremy@kilocharlie.us
Message 2
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| Subject: | GSC GTA In-Flight on my Series 3 |
--> Kitfox-List message posted by: "Fox5flyer" <morid@northland.lib.mi.us>
The physics of all this gets a little (way) over my head so take what I say
as "my opinion" only.
I would think that by running the engine with high power setting then
bringing the prop speed down by adding pitch is the same as going into a
higher gear in your car. No different and that's what the goal is. Where
the problem lies is running the rpms too low (5200) with high power setting
on the throttle (lots of air) withn lower rpms than the engine was designed
to operate, is essentially like having the car in 5th gear then going up
hill without shifting down. This, IMO, would be lugging the engine.
A manifold pressure instrument is invaluable when using an electric variable
pitch prop in that you can tell when your manifold pressure is too high in
proportion to engine speed. However, 2 strokers operate a little
differently and I'm not sure how one would be used with them or where one
could tap in a port. Also, jetting is an important consideration as 2
strokers are very sensitive to ambient temps, so this part is in the mix
also. Like I said earlier, plug readings are probably the best source of
how your engine is doing.
I might be all wet on this topic and I wish I could help out more on this
subject. I'm sure others have a better handle on it and can explain to your
satisfaction.
Deke
S5 Outback
Mikado MI
>
> Deke, I usually (almost always, actually) cruise my 582 at 5200 - I get
> low
> fuel burn and decent airspeed (63ish). I even flew all the 11 hrs to
> Virginia at 5200! But let's say I were to cruies at 6300 tomorrow - and
> I
> get 80 mph...IF were to have an in-flight prop, and I set the throttle
> at
> 6300, then dialed in the pitch to bring it down to 5200 or so, would I
> see
> that SAME 80 mph? Because all I'm doing is slowing down the
> motor...nothing
> more, correct?!
>
> Andrew
>
> <snip>
>
> Andrew,
>
> I want to throw in my $.02 worth...disclaimer...been about 3 years since
> I flew 2 stroke...and then was a 503, not 582...but principles are the
> same...also was not an "in-flight" adjustable prop, just ground
> adjustable.
>
> Increasing prop pitch (or said a different way, engine loading) in large
> increments would cause EGT's to go crazy, as stated already I believe,
> using the prop pitch to pull down the RPM is just reducing the amount of
> air but not the amount of fuel (richer). Going the other way could
> cause major problems, and should be carefully thought through.
>
> Similar but separate comment. Friend that has a Murphy Renegade tried
> the inflight adjustable IVO and got a little better takeoff/climb and a
> couple mph better cruise (draggy biplane isn't going to fast no matter
> how much horsepower...) Later was loaned a 2 blade Warp Drive to try
> and set to a fixed pitch, it out performed the adjustable IVO in all
> respects...different airframe, so your results may be different, but the
> IVO's are just not go fast props.
>
> Jeremy Casey
> jeremy@kilocharlie.us
>
>
Message 3
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| Subject: | GSC GTA In-Flight on my Series 3 |
--> Kitfox-List message posted by: "Andrew Matthaey" <spaghettiohead@hotmail.com>
Huh...my EGT's aren't very high as it is - 1100ish...
But thank you everybody for all the input! I may be better off putting my
money elsewhere after all :)
Andrew
>From: "Fox5flyer" <morid@northland.lib.mi.us>
>Reply-To: kitfox-list@matronics.com
>To: <kitfox-list@matronics.com>
>Subject: Kitfox-List: GSC GTA In-Flight on my Series 3
>Date: Thu, 29 Sep 2005 11:30:27 -0400
>
>--> Kitfox-List message posted by: "Fox5flyer" <morid@northland.lib.mi.us>
>
>
>The physics of all this gets a little (way) over my head so take what I say
>as "my opinion" only.
>I would think that by running the engine with high power setting then
>bringing the prop speed down by adding pitch is the same as going into a
>higher gear in your car. No different and that's what the goal is. Where
>the problem lies is running the rpms too low (5200) with high power setting
>on the throttle (lots of air) withn lower rpms than the engine was designed
>to operate, is essentially like having the car in 5th gear then going up
>hill without shifting down. This, IMO, would be lugging the engine.
>A manifold pressure instrument is invaluable when using an electric
>variable
>pitch prop in that you can tell when your manifold pressure is too high in
>proportion to engine speed. However, 2 strokers operate a little
>differently and I'm not sure how one would be used with them or where one
>could tap in a port. Also, jetting is an important consideration as 2
>strokers are very sensitive to ambient temps, so this part is in the mix
>also. Like I said earlier, plug readings are probably the best source of
>how your engine is doing.
>I might be all wet on this topic and I wish I could help out more on this
>subject. I'm sure others have a better handle on it and can explain to
>your
>satisfaction.
>Deke
>S5 Outback
>Mikado MI
>
>
> >
> > Deke, I usually (almost always, actually) cruise my 582 at 5200 - I get
> > low
> > fuel burn and decent airspeed (63ish). I even flew all the 11 hrs to
> > Virginia at 5200! But let's say I were to cruies at 6300 tomorrow - and
> > I
> > get 80 mph...IF were to have an in-flight prop, and I set the throttle
> > at
> > 6300, then dialed in the pitch to bring it down to 5200 or so, would I
> > see
> > that SAME 80 mph? Because all I'm doing is slowing down the
> > motor...nothing
> > more, correct?!
> >
> > Andrew
> >
> > <snip>
> >
> > Andrew,
> >
> > I want to throw in my $.02 worth...disclaimer...been about 3 years since
> > I flew 2 stroke...and then was a 503, not 582...but principles are the
> > same...also was not an "in-flight" adjustable prop, just ground
> > adjustable.
> >
> > Increasing prop pitch (or said a different way, engine loading) in large
> > increments would cause EGT's to go crazy, as stated already I believe,
> > using the prop pitch to pull down the RPM is just reducing the amount of
> > air but not the amount of fuel (richer). Going the other way could
> > cause major problems, and should be carefully thought through.
> >
> > Similar but separate comment. Friend that has a Murphy Renegade tried
> > the inflight adjustable IVO and got a little better takeoff/climb and a
> > couple mph better cruise (draggy biplane isn't going to fast no matter
> > how much horsepower...) Later was loaned a 2 blade Warp Drive to try
> > and set to a fixed pitch, it out performed the adjustable IVO in all
> > respects...different airframe, so your results may be different, but the
> > IVO's are just not go fast props.
> >
> > Jeremy Casey
> > jeremy@kilocharlie.us
> >
> >
>
>
http://toolbar.msn.click-url.com/go/onm00200415ave/direct/01/
Message 4
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| Subject: | Re: GSC GTA In-Flight on my Series 3 |
--> Kitfox-List message posted by: Aerobatics@aol.com
OK well........... there has been so much debate on this........ My
understanding is....
A two stroke, typicly does not like to be lugged down at all. In fact its
stressful internally.
Two strokes re designed to run in a fairly narrow rpm range, 4 stroke a
wider range......
Our Rotax also are tuned to the pipe/muffler.
Still, I would say, a in flight adjustable prop is an advantage, but I would
use it to fine tune and not use much range.
Example I would set it up so at full power climb on a 582 it would run at
6,600 to 6,700 RPM 50 mph
Then in the same climb I would add a bit pitch that would yield maybe 6,000
(too low to climb normally) then go to level flight and cruise at 5,600 to
5,800. I assume, that would require throttling back quite a bit.
Point is, I think for a two stroke we can benifit, a bit on climb, a bit on
cruise, but still need to run at the designed RPM with out over burdening.
In fact, I do have an IVO and like it , may get a inflight....
Hey, has anyone spoken to IVO on this?
Please, this is just my opinion.....
Dave KF2 582 IVO
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