Ok... now I see what you are getting at.
The trick, if there is one, is to descend at idle not reduced throttle.
When at idle the Rotax engine goes into a very rich mixture. On the way
down I normally do engine warms every thirty seconds or so. The engine warm
I use on the 582 is about ten seconds of full throttle with the nose up to
keep the prop under load. Also when descending I keep an eye on my EGTs...
then again I'm always checking my EGTs.
You will get into a problem if you pull the throttle back to say 3000 or
4000 rpm to descend. Basically it's an all or nothing situation. At idle
my engine only churns about 2500 in the descent with the throttle pulled
back to the idle stop. EGTs will drop maybe 50Deg from cruise. Engine warm
ups are always done if I notice a large drop in water temp. I never snap
the throttle open always let the engine pick up evenly with a direct
application of throttle.
So far the only hiccup I've had was last year when a perforated diaphragm in
the fuel pump made things quite interesting. On that occasion I had to land
with just about full power on to keep the engine from stalling... Gas was
leaking doun th impulse line like a fire hose... lots of fun! Gas
everywhere including some very hot exhausts.
Noel
-----Original Message-----
From: owner-kitfox-list-server@matronics.com
[mailto:owner-kitfox-list-server@matronics.com] On Behalf Of Paul Franz -
Merlin GT
Sent: Friday, November 28, 2008 4:12 PM
To: kitfox-list@matronics.com
Subject: RE: RE: 582 on floats with CAP
<paul@eucleides.com>
On Fri, November 28, 2008 11:02 am, Noel Loveys wrote:
> I'm not sure what you mean about a descent power problem...
Without a CAP, 582 users on this list have frequently stated that you have
to use a
step descent technique or you risk seizing from high engine rpm but low fuel
flow.
Your setup beats this problem! Long power off descents are the 2-stroke
engine killer
with a fixed pitch prop. Your writeup on procedure an example of what can be
learned
on this list. I was very pleased to learn this from you.
> pull the power
> and the cows will get larger! With two stroke engines pull the power to
> idle so the engine won't run lean. When I trained in the spam can I would
> only cut the power to 1800rpm until final when the heat went on, full rich
> and then pulled the throttle. A go around was heat off and full throttle.
>
>
> I haven't had a low power decent problem. I reset the pitch of the prop
> for climb rpm before descending so that power is ready to pull if needed.
>
>
> Usually, when I descend I pull the power almost completely. I had my idle
> set to around 1000 rpm. This was recommended to me so when the throttle
is
> completely closed the plane won't float on landing. I tend to plan
every
> landing as a short field (pond). That means no power on final or flare.
That is best practice technique in my view and matches my flight training
which came
from a high time military instructor.
There is one exception that the AK guys will tell you, and that is very cold
weather
operations, they don't like to run power to idle especially without cowl
flaps since
adding power for a go around is asking for cracked heads.
> Thinning out the prop before descending will allow the 582 to come up to
> climb power much faster once the throttle is opened and will of course
allow
> the engine to develop full rpm if a climb is needed.
The fixed pitch people can't do that, of course. Your setup and procedure
sounds
perfect to me.
--
Paul A. Franz
Registration/Aircraft - N14UW/Merlin GT
Engine/Prop - Rotax 914/NSI CAP
Bellevue WA
425.241.1618 Cell
