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Charlie,
I'm not even sure at what ground idle speed was when I flew the test. I
realized one day that I was using a lot of brake to keep the airplane down to a
brisk taxi on asphalt. Turns out my cable restraining nut had backed off and the
plane was idling at 900 rpm. My landings sure got better again when I set it
back to 750 rpm.
Bernie
----- Original Message -----
Sent: Tuesday, April 06, 2004 9:12
PM
Subject: [FlyRotary] Re: idle speeds
(prop stopped flight)
Hi Bernie,
What was your idle speed (plane stationary on
the ground) on the Lyc?
Would the results have been the same if you had
set the idle speed to
850-900 rpm & then flown the same test idling
& stopped prop?
WALTER KERR wrote:
> Hi
Charlie,
>
> I had a cruise prop (80 inch pitch) sensenich
metal prop on the 6A.
> When I was doing engine off glide testing, some
thought I would do
> better with engine stopped rather than turning.
Really had to slow way
> down to get prop to stop. Could not measure
the difference in glide
> engine stopped or windmilling. Really had to
go fast, over a hundred
> to get it going again!
>
>
Bernie Kerr, painting the 9A waiting to get rotary back from Bruce T
>
at SnF
>
> ----- Original Message
-----
> From: Charlie & Tupper England
<mailto:cengland@netdoor.com>
>
To: Rotary motors in aircraft <mailto:flyrotary@lancaironline.net>
>
Sent: Sunday, April 04, 2004 11:06 PM
> Subject:
[FlyRotary] Re: idle speeds
>
> I agree
with Jim about this. I've had similar problems with a
Lyc
> powered RV-4. Anything over about
800 prop rpm caused a lot of
>
float.
> I'd be interested to see the
calculations on whether a really highly
>
pitched cruise prop is producing thrust at 800-850 rpm & 60-70mph.
I
> think that it's at least safe to say that
the airflow isn't
> driving
the
> prop disc & producing drag like a
climb or c/s prop.
>
> I wonder what
engine-stopped glide angle would look like
compared
> to
the
> angle we get used to while being pulled
along by the engine on final.
> This could be a
significant safety issue if there's an engine
failure
> when we have become acclimated to
unknowingly carrying power
> (thrust)
on
>
final.
>
>
Charlie
>
>
>
> Jim Sower
wrote:
>
> > <... I need to get the
idle speed way down ...>
> > You sure
do. I've regaled you several times about my EZ with
an
> O-235
> >
idling at 800-900 rpm that could NEVER be slowed down enough
to
> land -
> >
floated 1000' or more down every damned runway I encountered.
> Landed
> >
fine when I set the idle down to 500-600 rpm. Ran rough as
a
> cob at
> >
that speed on the ground (which is why it had been set so
high),
> but I
>
> could advance it to 800 for ground ops, and go to the idle stop
on
> > final. With all your power, I
would emphatically recommend that
>
you
> > back the idle down till it will just
barely idle on the ground.
>
You
> > can always taxi above the idle stop,
but you can never land
> below it.
> > I would also strongly recommend a
shutdown switch (injectors?
>
pumps?)
> > near the throttle quadrant for
convenient shutdown on final. A
> >
guarded switch (guarded ON) would satisfy safety
considerations,
>
and
> > be convenient enough that you could
shut down nearly as easily as
> > pulling the
mixture.
> >
>
> That way, you have all the bases covered ... Jim
S.
> >
>
>
> > John Slade
wrote:
> >
>
>> Last week we had some discussion on idle speeds, and I think
the
> >>
consensus
> >> was to keep it around 2000
or a little under. Just for information
>
>> for other
> >> canard pusher
people, I think 2000 is going to be a real
>
problem for
> >> me.
At
> >> the current 1850 setting with the
big 3 66/84 prop I have on she's
> >>
pushing
> >> hard against the brakes. I
think I could taxi the length of the
> >>
runway at
> >> idle and be doing 30/40 kts
at the end. On a short (3400)
> runway
the
> >>
only
> >> way to stop might be kill the
engine once on the ground, or
> even
on
> >>
short
> >> final. So I need to get the
idle speed way down.
> >> John Slade (more
power than I know what to do with)
>
>>
> >> >>
Homepage: http://www.flyrotary.com/
>
>> >> Archive: http://lancaironline.net/lists/flyrotary/List.html
>
>>
> >
--
> > Jim Sower ... Destiny's
Plaything
> > Crossville, TN; Chapter
5
> > Long-EZ N83RT, Velocity
N4095T
> >
>
>
>
>
>
> >>
Homepage: http://www.flyrotary.com/
>
>> Archive: http://lancaironline.net/lists/flyrotary/List.html
>
>>
Homepage: http://www.flyrotary.com/
>>
Archive: http://lancaironline.net/lists/flyrotary/List.html
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