Today's Message Index:
----------------------
1. 02:11 AM - RPM vs MP (M Ferguson)
2. 04:44 AM - pennzoil shelf life (Airgriff2@aol.com)
3. 06:06 AM - Re: RPM vs MPRPM vs MP (Thom Riddle)
4. 02:32 PM - Re: RPM vs MP (Duncan McFadyean)
5. 03:29 PM - Priming the oil system (Peter Rees)
6. 04:09 PM - Re: Priming the oil system (Gilles Thesee)
Message 1
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--> RotaxEngines-List message posted by: M Ferguson <malann@bigfoot.com.au>
Hi Dave,
I have about 180 hrs on an Esqual. My 912uls has always been sweetest at
around 5200 revs so it stays there around 90% of the time. If I want to go
fast its full throttle(135-140 kts) If I want to dawdle I come back to
22"map giving about 108 kts. Interestingly at 135kts at 6000-7000' it
will only drop about 1-2 kts if I leave the throttle wide open and drop
back to 4800 revs, but engine becomes less smooth. I had my prop balanced
in flight at 5200 and it did not change the feel but it changed the sound
enough that when we flew home we took some time to accept that things were
hunky dory.
Bear in mind that at 23"map you are not producing a lot of power, but
because speed goes up about 1.6% approx/1000' this helps to compensate the
reduction in map at 6000'. I would just pick a revs that the engine feels
sweetest and go for it. Control the speed with manifold pressure.
Malcolm
--
Message 2
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| Subject: | pennzoil shelf life |
Here is the response from Pennzoil Co. on "shelf life".Bob,=A0Thank you for
your interest in Pennzoil products. The shelf life on all of our 2-cycle and
4-cycle engine oils is 4 years.=A0If you have any other questions or comments,
please feel free to contact our Technical Service Group at 1-800-458-4998.=A0Regards,
=A0Technical Service Department
> -----Original Message-----
> From: postmaster@pennzoil.com [mailto:postmaster@pennzoil.com]
> Sent: Friday, February 24, 2006 6:01 AM
> To: Prd Mkt-PZLWebmaster, SLUBE
> Subject: Pennzoil Contact Form - General Information Request
>
>
> 02/24/2006 6:00:32 AM
Bob Griffin
airgriff2@aol.com
Comments:
is there any "shelf life" on your 2 or 4 stroke oils? Thank you Bob
Message 3
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| Subject: | Re: RPM vs MPRPM vs MP |
Dave,
Here is how I do it in my Titan Tornado which has a 912UL (80hp) engine
and the GSC in-flight adjustable prop.
Take-off and initial climb to minimum turn-back altitude (about 400
AGL).
I set the pitch so that at full throttle and Vy speed, the tach is
reading 5,500 rpm (max. continuous cruise speed). I could set a little
finer pitch to get 5,800 rpm but always stay out of the yellow band.
Don't ask me what that pitch is but because I don't know, but have it
marked on the vernier prop control. This is an advantage of the vernier
over the electric operated props.
Cruise Climb
I dial in two turns more of prop pitch (about 2 degrees more) which
gives me 5,200 rpm at full throttle at a speed of about midway between
Vy and normal cruise speed. I know this because GSC says that one full
turn of the control is about degree change in pitch. The manifold
pressure in this regime is of no concern to me.
En-route Cruise
I dial in enough pitch to lower the rpm to what is comfortable to me
(noise etc) that will allow full throttle operation. For me this is
about 4,500-4,800 rpm depending upon how fast I want to go. Above 5,000
rpm it gets pretty noisy. The manifold pressure is what ever full
throttle allows at the density altitude I'm flying at.
Slow Cruise
This is the only configuration I use less than full throttle. I use the
same prop pitch here as I use for en-route cruise and just throttle
back to whatever speed I want to fly.
Pattern Work
I use the Cruise Climb pitch setting while in the pattern until I'm on
final approach then go to take-off pitch so it will be ready for
go-around if required. Throttle is whatever is required to hold the
speed needed on whichever leg I'm on.
Note the following:
- The primary purpose of an in-flight adjustable prop is to allow the
pilot to control what rpm the engine runs at under all flight regimes.
- The engine is generally most efficient near full throttle operation.
- From best climb to best cruise on my Titan is about 4 degrees
difference in prop pitch (4 turns on the GSC vernier control).
- At full throttle, manifold pressure goes down with increased density
altitude no matter what type of prop you have.
- Power and thrust produced is a function manifold pressure, so as you
climb, power produced decreases.
- To maintain power produced as you climb higher takes about 67 rpm
increase per 1,000' increase in density altitude.
- TAS (not IAS) goes up about 1% per 1,000' increase in density
altitude at a constant power setting (not constant rpm).
- IAS goes down relative to TAS about 2% per 1,000' increase in density
altitude.
I hope this helps. Let me know if you have more questions.
Thom in Buffalo
Message 4
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--> RotaxEngines-List message posted by: "Duncan McFadyean" <ami@mcfadyean.freeserve.co.uk>
Where the engine sounds sweetest has a lot to do with how the carbs are set
up; i.e. the point at which they are nicely in balance. Bear in mind that
the asymmetry of the carb. arms resulting from (non-precision) manufacturing
tolerance means that it is impossible to achieve balance across the useable
rev-range.
There has been alot of debate about lower engine speeds resulting in higher
rates of wear; but nothing on this issue from Rotax themselves. Meanwhile,
some training ultralights in the US are claiming 3000+hours engine life.
It remains that (in the case of the ULS) the engine is most efficient at
4800 rpm (the max torque speed) and falls off the cam at about 3800 rpm.
There seems to be a common 'roughness' between about 4100 and 4400 rpm;
which is coincident with a slight dip and rise in the torque and bsfc curves
respectively, suggesting that the engine is not 'happy' in this band.
DuncanMcF.
----- Original Message -----
From: "M Ferguson" <malann@bigfoot.com.au>
Sent: Saturday, February 25, 2006 10:09 AM
Subject: RotaxEngines-List: RPM vs MP
> --> RotaxEngines-List message posted by: M Ferguson
> <malann@bigfoot.com.au>
>
> Hi Dave,
> I have about 180 hrs on an Esqual. My 912uls has always been sweetest at
> around 5200 revs so it stays there around 90% of the time. If I want to go
> fast its full throttle(135-140 kts) If I want to dawdle I come back to
> 22"map giving about 108 kts. Interestingly at 135kts at 6000-7000' it
> will only drop about 1-2 kts if I leave the throttle wide open and drop
> back to 4800 revs, but engine becomes less smooth. I had my prop balanced
> in flight at 5200 and it did not change the feel but it changed the sound
> enough that when we flew home we took some time to accept that things were
> hunky dory.
> Bear in mind that at 23"map you are not producing a lot of power, but
> because speed goes up about 1.6% approx/1000' this helps to compensate the
> reduction in map at 6000'. I would just pick a revs that the engine feels
> sweetest and go for it. Control the speed with manifold pressure.
> Malcolm
>
>
> --
>
>
> http://www.matronics.com/Navigator?RotaxEngines-List
>
>
>
Message 5
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| Subject: | Priming the oil system |
We have left the oil system of G-MFHI totally open (due to gearbox removal) for
a couple of weeks but are now ready to start the engine again.
Can anyone please tell me where I can find information on priming the oil system?
as I'm keen to avoid any airlocks.
Thanks
Peter
Message 6
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| Subject: | Re: Priming the oil system |
Peter Rees a crit :
>
> We have left the oil system of G-MFHI totally open (due to gearbox
> removal) for a couple of weeks but are now ready to start the engine
> again.
>
> Can anyone please tell me where I can find information on priming the
> oil system? as I'm keen to avoid any airlocks.
>
Peter,
You do not tell the engine model (I'm afraid G-MFHI is not known outside
your country;-), but let's say it is a 912 or something.
What about this document :
http://www.rotax-aircraft-engines.com/pdf/dokus/d01875.pdf
You may wish to subscribe at
http://www.rotax-aircraft-engines.com/aircraft/aircraft.nsf/index?Openpage
for document retrieval and free e-mail update service, like most Rotax
flyers do.
Regards,
Gilles Thesee
Grenoble, France
http://contrails.free.fr
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