X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 19 Jun 2011 11:30:41 -0400 Message-ID: X-Original-Return-Path: Received: from [198.64.152.110] (HELO sdc.com) by logan.com (CommuniGate Pro SMTP 5.4.0) with ESMTP id 5024959 for lml@lancaironline.net; Sun, 19 Jun 2011 00:25:48 -0400 Received-SPF: pass receiver=logan.com; client-ip=198.64.152.110; envelope-from=ronald@sdc.com Received: from [192.168.1.38] [24.127.195.226] by sdc.com with ESMTP (SMTPD-11.5) id 5f2c00001b9d1f5a; Sun, 19 Jun 2011 00:15:59 -0400 User-Agent: Microsoft-MacOutlook/14.2.0.101115 X-Original-Date: Sun, 19 Jun 2011 00:25:09 -0400 Subject: Re: [LML] Re: And how about a full feathering prop? From: RONALD STEVENS X-Original-To: Lancair Mailing List X-Original-Message-ID: Thread-Topic: [LML] Re: And how about a full feathering prop? In-Reply-To: Mime-version: 1.0 Content-type: multipart/alternative; boundary="B_3391287912_956444" > This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. --B_3391287912_956444 Content-type: text/plain; charset="ISO-8859-1" Content-transfer-encoding: quoted-printable Hi Robert Thanks for the explanation, and sure as hell I am going to try to see the glide ratio as it has been debated many times by NON lancair owners I know. Now for your explanation, I am thinking you are doing your test with a running engine, but that is not when we are needing a full feather prop, right? We need it when the mill dies on us, so no oil pressure so therefore no way to feather in any kind of form, right? (now I have been told by a Aerostar owner that they then just crank the engine to get some low oil pressure and this way they feather, I am not sur= e if this would work as I do not have this experience at all) But I do know that when the engine quiets, we try to restart it first by switching the fuel selector, crank until we figured out that it won't start and then=8A=8Awell then it would be handy to have the full feather prop, right? (or do I see this wrong and if so please tell me, I am here to learn :) A glide ratio of 18:1 is fantastic, this is actually the same as the Evolution, and if I am not mistaken, with the same glide speed :) From: Robert R Pastusek Reply-To: Lancair Mailing List Date: Sat, 18 Jun 2011 20:32:00 -0400 To: Subject: [LML] Re: And how about a full feathering prop? Ronald wrote: =20 For what I have gathered so far the lancair 4p has a glide ratio similar like a piano LOL In other words if the engine quits then open the door, throw out your keys because there is where you land LOL =20 Well, this might not be true, or is it? =20 So how about the full feathering prop ? Does anyone have experience with th= e before and after installation? How much they cost and data? =20 And I needed to respond to this=8A =20 My IV-P has a glide ratio (at 120 KIAS) of between 5:1 and 20:1, depending on configuration. The difference is truly amazing/impressive/sobering=8A depending on your situation and mind set. With the gear and flaps down and the RPM at max (prop all the way in), the glide ratio approximates that of = a brick=8Anot really, but you=B9re coming down so fast relative to forward progress that it=B9s difficult to plan and execute a planned touchdown (at least for me). With the gear and flaps up, AND THE PROP CONTROL ALL THE WAY OUT, my glide ratio at gross weight is approximately 18:1, increasing to a bit better than 20:1 at 800# under gross. At this glide ratio, the performance and =B3sight picture=B2 approximates that of some gliders. It=B9s eas= y to plan and execute an approach and landing to a pre-planned spot=8Aideally a runway. I have practiced this many times from various altitudes/distances from the airport to a full stop on the runway, using the gear to increase m= y descent rate, and then the flaps and/or the prop control to adjust the touchdown point. Using the prop control is ideal because the drag effect/descent rate increase almost immediately reversible by pushing it back in. Not so with the flaps. One feature of my Chelton EFIS is a wind-adjusted glide range predictor. I have tested this many times starting at altitudes up to 17,500=B9 and (set at 18:1) gives me a very accurate and immediate sight picture of airfields within glide range. If it=B9s within the green circle, I can turn toward an airfield and execute a safe landing there. My MT 4-blade is not full feathering, but allows the engine to run a= t approximately 700 RPM when at idle and the RPM set to min. I believe this i= s pretty close to 0 thrust, as the engine idles at approximately 600 RPM on the ground.=20 =20 So, in summary, the throw out the keys and follow them down scenario can be executed if you really want to go down, but a planned glide at 120 KIAS (very close to best glide for my airplane) in clean configuration yields approximately the performance of a 2-place sail plane=8Band you have the ability to transition easily between these limits as needed. Try it; you=B9ll be impressed. =20 Bob =20 PS: I considered and rejected a full feathering prop for what I have. Wouldn=B9t trade for any amount of money=8A --B_3391287912_956444 Content-type: text/html; charset="ISO-8859-1" Content-transfer-encoding: quoted-printable
Hi Robert

Thanks for the explanation, and sure as hell I am going to try to see= the glide ratio as it has been debated many times by NON lancair owners I k= now.

Now for your explanation, I am thinking you ar= e doing your test with a running engine, but that is not when we are needing= a full feather prop, right? We need it when the mill dies on us, so no oil = pressure so therefore no way to feather in any kind of form, right? 

(now I have been told by a Aerostar owner that they t= hen just crank the engine to get some low oil pressure and this way they fea= ther, I am not sure if this would work as I do not have this experience at a= ll)

But I do know that when the engine quiets, we t= ry to restart it first by switching the fuel selector, crank until we figure= d out that it won't start and then……well then it would be handy = to have the full feather prop, right? (or do I see this wrong and if so plea= se tell me, I am here to learn :)

A glide ratio of = 18:1 is fantastic, this is actually the same as the Evolution, and if I am n= ot mistaken, with the same glide speed :)

From: Robert R Pastusek <rpastusek@htii.com>
Reply= -To: Lancair Mailing List <lml@lancaironline.net>
Date: Sat, 18 Jun 2011 20:32:00 -0400
To: <lml@lancaironline.net>= ;
Subject: [LML] Re: And how about= a full feathering prop?

Ronald wrote:

 

For what I have gathered so far the lancair 4p= has a glide ratio similar like a piano LOL In other words if the engine qui= ts then open the door, throw out your keys because there is where you land L= OL

 

Well, this might not be = true, or is it? 

<= span style=3D"font-size: 13.5pt; color: black; font-family: Calibri, sans-seri= f; "> 

So ho= w about the full feathering prop ? Does anyone have experience with the befo= re and after installation?  How much they cost and data?

 

And I needed to respond to thi= s…

 = ;

My IV-P has a glide ra= tio (at 120 KIAS) of between 5:1 and 20:1, depending on configuration. The d= ifference is truly amazing/impressive/sobering… depending on your situ= ation and mind set. With the gear and flaps down and the RPM at max (prop al= l the way in), the glide ratio approximates that of a brick…not really= , but you’re coming down so fast relative to forward progress that it&= #8217;s difficult to plan and execute a planned touchdown (at least for me).= With the gear and flaps up, AND THE PROP CONTROL ALL THE WAY OUT, my glide = ratio at gross weight is approximately 18:1, increasing to a bit better than= 20:1 at 800# under gross. At this glide ratio, the performance and “s= ight picture” approximates that of some gliders. It’s easy to pl= an and execute an approach and landing to a pre-planned spot…ideally a= runway. I have practiced this many times from various altitudes/distances f= rom the airport to a full stop on the runway, using the gear to increase my = descent rate, and then the flaps and/or the prop control to adjust the touch= down point. Using the prop control is ideal because the drag effect/descent = rate increase almost immediately reversible by pushing it back in. Not so wi= th the flaps.  One feature of my = Chelton EFIS is a wind-adjusted glide range predictor. I have tested this ma= ny times starting at altitudes up to 17,500’ and  (set at 18:1) gives me a very accurate and immediate = sight picture of airfields within glide range. If it’s within the gree= n circle, I can turn toward an airfield and execute a safe landing there. My= MT 4-blade is not full feathering, but allows the engine to run at approxim= ately 700 RPM when at idle and the RPM set to min. I believe this is pretty = close to 0 thrust, as the engine idles at approximately 600 RPM on the groun= d.

 

So, in summary, the throw o= ut the keys and follow them down scenario can be executed if you really want= to go down, but a planned glide at 120 KIAS (very close to best glide for m= y airplane) in clean configuration yields approximately the performance of a= 2-place sail plane—and you have the ability to transition easily betw= een these limits as needed. Try it; you’ll be  impressed.

 

= Bob

 

PS: I considered and reject= ed a full feathering prop for what I have. Wouldn’t  trade for any amount of money…

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