X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 13 Sep 2009 23:42:50 -0400 Message-ID: X-Original-Return-Path: Received: from smtp-auth-04.mx.pitdc1.expedient.net ([206.210.66.137] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTPS id 3849813 for lml@lancaironline.net; Sun, 13 Sep 2009 22:01:16 -0400 Received-SPF: none receiver=logan.com; client-ip=206.210.66.137; envelope-from=rpastusek@htii.com Received: from HTBOB001 (static-72-66-86-7.washdc.fios.verizon.net [72.66.86.7]) by smtp-auth-04.mx.pitdc1.expedient.net (Postfix) with ESMTPA id 7439AE451D for ; Sun, 13 Sep 2009 22:00:41 -0400 (EDT) From: "Robert Pastusek" X-Original-To: "'Lancair Mailing List'" References: In-Reply-To: Subject: RE: [LML] Re: Glide Ratio for the Lancair IVP X-Original-Date: Sun, 13 Sep 2009 22:00:37 -0400 X-Original-Message-ID: <0a4d01ca34df$27a4bee0$76ee3ca0$@com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0A4E_01CA34BD.A0931EE0" X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: Aco0zDm6c3xVNg2BTbyKDOW+KOcqRgAEU+Lw Content-Language: en-us This is a multi-part message in MIME format. ------=_NextPart_000_0A4E_01CA34BD.A0931EE0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Sorry, this should have read, .I was able to make a 180 and get to an AIRPORT behind me. I expect most of you figured this out by now.J Bob John Hafen wrote: What do you recommend as the "Glide Ratio" in the Chelton System User Programmed Settings? John, I'm using 20:1 and it seems just about right. In a couple of tests (from 10,000 and 17,000') I was able to make a 180 and get to an airplane behind me with a bit of altitude to spare at the end. I think I could do a bit better from higher up. I considered going to 22:1, but decided against it because I was testing in a "known" situation/plan for this test and didn't allow for reaction/analysis time (WTFO.to use and old Navy expression). I'd also strongly suggest you set a value and test it yourself (carefully!), as the largest factor is the windmilling prop. My MT 4-blade will almost feather, maintaining about 700 RPM with the throttle at full idle, and giving me approx 600 FPM down at 120 KTS IAS. Even a small amount of additional RPM increased the descent rate dramatically; likewise, stopping the prop (if you can), will yield an even better glide ratio. This later observation is from an actual engine failure in flight many years ago; I have not tried this with my Lancair. I had a camshaft drive gear failure in Cherokee 235 at 13,500 near Winslow, AZ. I lifted the nose to try to stop the prop, and the very bad sounds coming from the engine compartment-I could hear the engine eating itself. Had to slow to very near stall to do this, but once I went back to best glide speed, was able to dead-stick into Winslow easily. Based on my earlier practice, I'd have bet there was no way to make the airport. After cleaning my pants and fixing the airplane, I actually tested this. Stopping the prop on that airplane added at least 50% to the glide range. I'm not sure this last part can be related to Lancair operation at all-and I don't intend to test/practice this maneuver in mine, but if I ever need to do it for real, I'll likely try to stop the prop to pick up the extra range. Hope this helps. Bob P ------=_NextPart_000_0A4E_01CA34BD.A0931EE0 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Glide Ratio for the Lancair IVP

Sorry, this should have read, …I was able to make a = 180 and get to an AIRPORT behind me… I expect most of you figured this out by = now…J <= /span>

 

Bob

 <= /o:p>

 

John Hafen wrote:

What do you recommend as the “Glide Ratio” in the Chelton = System User Programmed Settings?

John,

I’m using 20:1 and it seems just about right. In a = couple of tests (from 10,000 and 17,000’) I was able to make a 180 and get = to an airplane behind me with a bit of altitude to spare at the end. I think I could do = a bit better from higher up. I considered going to 22:1, but decided against = it because I was testing in a “known” situation/plan for this = test and didn’t allow for reaction/analysis time (WTFO…to use and old Navy = expression).

 

I’d also strongly suggest you set a value and test = it yourself (carefully!), as the largest factor is the windmilling prop. My MT = 4-blade will almost feather, maintaining about 700 RPM with the throttle at full = idle, and giving me approx 600 FPM down at 120 KTS IAS. Even a small amount of = additional RPM increased the descent rate dramatically; likewise, stopping the prop = (if you can), will yield an even better glide ratio.

 

This later observation is from an actual engine failure = in flight many years ago; I have not tried this with my Lancair. I had a = camshaft drive gear failure in  Cherokee 235 at 13,500 near Winslow, AZ. I = lifted the nose to try to stop the prop, and the very bad sounds coming from = the engine compartment—I could hear the engine eating itself. Had to = slow to very near stall to do this, but once I went back to best glide speed, was = able to dead-stick into Winslow easily. Based on my earlier practice, I’d = have bet there was no way to make the airport. After cleaning my pants and fixing = the airplane, I actually tested this. Stopping the prop on that airplane = added at least 50% to the glide range.

 

I’m not sure this last part can be related to = Lancair operation at all—and I don’t intend to test/practice this maneuver in = mine, but if I ever need to do it for real, I’ll likely try to stop the prop to pick = up the extra range.

 

Hope this helps.


Bob P

------=_NextPart_000_0A4E_01CA34BD.A0931EE0--