Return-Path: Received: from [65.54.169.103] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.2b1) with ESMTP id 3146505 for flyrotary@lancaironline.net; Mon, 05 Apr 2004 07:58:06 -0400 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Mon, 5 Apr 2004 04:58:05 -0700 Received: from 199.183.216.218 by bay3-dav73.adinternal.hotmail.com with DAV; Mon, 05 Apr 2004 11:58:05 +0000 X-Originating-IP: [199.183.216.218] X-Originating-Email: [kerrjb@msn.com] X-Sender: kerrjb@msn.com From: "WALTER KERR" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: idle speeds (prop stopped flight) Date: Mon, 5 Apr 2004 07:57:46 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0083_01C41AE3.B2378D60" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 8.5 X-MimeOLE: Produced By MSN MimeOLE V8.50.0017.1202 Seal-Send-Time: Mon, 5 Apr 2004 07:57:52 -0400 Message-ID: X-OriginalArrivalTime: 05 Apr 2004 11:58:05.0933 (UTC) FILETIME=[4167E1D0:01C41B05] This is a multi-part message in MIME format. ------=_NextPart_000_0083_01C41AE3.B2378D60 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable 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 -----=20 From: Charlie & Tupper England=20 To: Rotary motors in aircraft=20 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=20 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=20 pitched cruise prop is producing thrust at 800-850 rpm & 60-70mph. I=20 think that it's at least safe to say that the airflow isn't driving = the=20 prop disc & producing drag like a climb or c/s prop. I wonder what engine-stopped glide angle would look like compared to = the=20 angle we get used to while being pulled along by the engine on final.=20 This could be a significant safety issue if there's an engine failure=20 when we have become acclimated to unknowingly carrying power (thrust) = on=20 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=20 > idling at 800-900 rpm that could NEVER be slowed down enough to land = -=20 > floated 1000' or more down every damned runway I encountered. = Landed=20 > 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=20 > could advance it to 800 for ground ops, and go to the idle stop on=20 > 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. =20 > I would also strongly recommend a shutdown switch (injectors? = pumps?)=20 > near the throttle quadrant for convenient shutdown on final. A=20 > guarded switch (guarded ON) would satisfy safety considerations, and = > be convenient enough that you could shut down nearly as easily as=20 > pulling the mixture. > > That way, you have all the bases covered ... Jim S. > =20 > > John Slade wrote: > >> Last week we had some discussion on idle speeds, and I think the=20 >> consensus >> was to keep it around 2000 or a little under. Just for information=20 >> for other >> canard pusher people, I think 2000 is going to be a real problem = for=20 >> me. At >> the current 1850 setting with the big 3 66/84 prop I have on she's=20 >> pushing >> hard against the brakes. I think I could taxi the length of the=20 >> runway at >> idle and be doing 30/40 kts at the end. On a short (3400) runway = the=20 >> 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 >> > --=20 > Jim Sower ... Destiny's Plaything > Crossville, TN; Chapter 5 > Long-EZ N83RT, Velocity N4095T > =20 > >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_0083_01C41AE3.B2378D60 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Charlie,
 
I had a cruise prop (80 inch pitch) sensenich metal prop on the 6A. = When I=20 was doing engine off glide testing, some thought I would do better with = engine=20 stopped rather than turning. Really had to slow way down to get prop to = stop.=20 Could not measure the difference in glide engine stopped or windmilling. = Really=20 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=20 SnF
----- Original Message -----
From: Charlie & Tupper England =
To: Rotary motors in = aircraft
Sent: Sunday, April 04, 2004 = 11:06=20 PM
Subject: [FlyRotary] Re: idle=20 speeds

I agree with Jim about this. I've had similar problems = with a=20 Lyc
powered  RV-4. Anything over about 800 prop rpm caused a = lot of=20 float.
I'd be interested to see the calculations on whether a = really=20 highly
pitched cruise prop is producing thrust at 800-850 rpm = & =20 60-70mph. I
think that it's at least safe to say that the airflow = isn't=20 driving the
prop disc & producing drag like a climb or c/s=20 prop.

I wonder what engine-stopped glide angle would look like = compared=20 to the
angle we get used to while being pulled along by the engine = on=20 final.
This could be a significant safety issue if there's an = engine=20 failure
when we have become acclimated to unknowingly carrying = power=20 (thrust) on
final.

Charlie



Jim Sower=20 wrote:

> <... I need to get the idle speed way down=20 ...>
> You sure do.  I've regaled you several times = about my EZ=20 with an O-235
> idling at 800-900 rpm that could NEVER be = slowed down=20 enough to land -
> floated 1000' or more down every damned = runway I=20 encountered.  Landed
> fine when I set the idle down to = 500-600=20 rpm.  Ran rough as a cob at
> that speed on the ground = (which is=20 why it had been set so high), but I
> could advance it to 800 = for=20 ground ops, and go to the idle stop on
> final.  With all = your=20 power, I would emphatically recommend that you
> back the idle = down=20 till it will just barely idle on the ground.  You
> can = always=20 taxi above the idle stop, but you can never land below it.  =
> I=20 would also strongly recommend a shutdown switch (injectors?  = pumps?)=20
> near the throttle quadrant for convenient shutdown on = final.  A=20
> guarded switch (guarded ON) would satisfy safety = considerations, and=20
> be convenient enough that you could shut down nearly as = easily as=20
> pulling the mixture.
>
> That way, you have all = the bases=20 covered ... Jim S.
> 
>
> John Slade=20 wrote:
>
>> Last week we had some discussion on idle = speeds,=20 and I think the
>> consensus
>> was to keep it = around 2000=20 or a little under. Just for information
>> for = other
>>=20 canard pusher people, I think 2000 is going to be a real problem for=20
>> me. At
>> the current 1850 setting with the big = 3 66/84=20 prop I have on she's
>> pushing
>> hard against the = brakes.=20 I think I could taxi the length of the
>> runway = at
>> idle=20 and be doing 30/40 kts at the end. On a short (3400) runway the =
>>=20 only
>> way to stop might be kill the engine once on the = ground, or=20 even on
>> short
>> final. So I need to get the = idle speed=20 way down.
>> John Slade (more power than I know what to do=20 with)
>>
>> >>  Homepage:  http://www.flyrotary.com/
>&= gt;=20 >>  Archive:   http://lancai= ronline.net/lists/flyrotary/List.html
>>
>=20 --
> Jim Sower ... Destiny's Plaything
> Crossville, TN; = Chapter=20 5
> Long-EZ N83RT, Velocity N4095T
> =20
>



>>  Homepage:  http://www.flyrotary.com/
>&= gt; =20 Archive:   http://lancai= ronline.net/lists/flyrotary/List.html
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