X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 20 Jun 2011 08:00:14 -0400 Message-ID: X-Original-Return-Path: Received: from qmta15.emeryville.ca.mail.comcast.net ([76.96.27.228] verified) by logan.com (CommuniGate Pro SMTP 5.4.0) with ESMTP id 5025584 for lml@lancaironline.net; Sun, 19 Jun 2011 22:08:29 -0400 Received-SPF: pass receiver=logan.com; client-ip=76.96.27.228; envelope-from=j.hafen@comcast.net Received: from omta17.emeryville.ca.mail.comcast.net ([76.96.30.73]) by qmta15.emeryville.ca.mail.comcast.net with comcast id y27C1g0051afHeLAF27sqT; Mon, 20 Jun 2011 02:07:52 +0000 Received: from [10.0.1.5] ([24.17.111.171]) by omta17.emeryville.ca.mail.comcast.net with comcast id y2Ai1g00i3hvfg88d2AjF0; Mon, 20 Jun 2011 02:10:43 +0000 From: John Hafen Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: multipart/alternative; boundary=Apple-Mail-45--484009487 Subject: Re: [LML] Re: And how about a full feathering prop? X-Original-Date: Sun, 19 Jun 2011 19:07:52 -0700 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: X-Mailer: Apple Mail (2.1084) --Apple-Mail-45--484009487 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 Bob: Did you reject the fully feathering prop idea so you could manipulate = the prop to adjust drag on the way down, versus just go full feather for = a longer glide? John Hafen On Jun 18, 2011, at 5:32 PM, Robert R Pastusek wrote: 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 =20 So how about the full feathering prop ? Does anyone have experience with = the before and after installation? How much they cost and data? =20 And I needed to respond to this=85 =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=85 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=85not really, but you=92re = coming down so fast relative to forward progress that it=92s 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 =93sight = picture=94 approximates that of some gliders. It=92s easy to plan and = execute an approach and landing to a pre-planned spot=85ideally 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 my 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=92 and (set at 18:1) = gives me a very accurate and immediate sight picture of airfields within = glide range. If it=92s 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 at approximately 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 ground. =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=97and you = have the ability to transition easily between these limits as needed. = Try it; you=92ll be impressed. =20 Bob =20 PS: I considered and rejected a full feathering prop for what I have. = Wouldn=92t trade for any amount of money=85 --Apple-Mail-45--484009487 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=windows-1252 Bob:

Did you reject the fully = feathering prop idea so you could manipulate the prop to adjust drag on = the way down, versus just go full feather for a longer = glide?

John = Hafen


On Jun 18, 2011, at 5:32 = PM, Robert R Pastusek wrote:

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 quits then = open the door, throw out your keys because there is where you land = LOL
Well, this might not be true, or is = it? 
 
So how about the full feathering prop ? Does = anyone have experience with the before and after installation?  How = much they cost and data?
And I needed to respond to = this=85
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=85 = 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=85not really, but you=92re coming down so fast relative = to forward progress that it=92s 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 =93sight picture=94 approximates that = of some gliders. It=92s easy to plan and execute an approach and landing = to a pre-planned spot=85ideally 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 my 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=92 and  (set at = 18:1) gives me a very accurate and immediate sight picture of airfields = within glide range. If it=92s 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 at approximately 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 = ground.
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=97and you have the = ability to transition easily between these limits as needed. Try it; = you=92ll be  impressed.<= /span>
PS: I = considered and rejected a full feathering prop for what I have. = Wouldn=92t  trade for any amount = of = money=85

<= /body>= --Apple-Mail-45--484009487--