Return-Path: Sender: (Marvin Kaye) To: lml@lancaironline.net Date: Fri, 06 Aug 2004 20:00:25 -0400 Message-ID: X-Original-Return-Path: Received: from [208.57.0.48] (HELO mgci.com) by logan.com (CommuniGate Pro SMTP 4.2) with SMTP id 355342 for lml@lancaironline.net; Fri, 06 Aug 2004 19:35:57 -0400 Received-SPF: none receiver=logan.com; client-ip=208.57.0.48; envelope-from=woodruff@swefco.com Received: (qmail 2960 invoked by uid 0); 6 Aug 2004 23:35:33 -0000 Received: from unknown (HELO ?192.168.0.2?) (66.18.129.84) by mgci.com with SMTP; 6 Aug 2004 23:35:33 -0000 User-Agent: Microsoft-Entourage/10.1.4.030702.0 X-Original-Date: Fri, 06 Aug 2004 16:35:26 -0700 Subject: Re: [LML] Re: Shannon Knoepflein's Legacy Accident From: Hal Woodruff X-Original-To: Lancair Mailing List X-Original-Message-ID: In-Reply-To: Mime-version: 1.0 Content-type: multipart/alternative; boundary="B_3174654926_21249768" > 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_3174654926_21249768 Content-type: text/plain; charset="ISO-8859-1" Content-transfer-encoding: quoted-printable I=B9m really curious as to what the real best L/D speed is for the Lancair IV=B9s and Legacies. I was told in my training at the factory that the best glide speed is approximately 120 knots (for the IV), knowing full well that this speed is dependent on the weight of the aircraft. I also remember someone telling me that best glide speed in any airplane is the same as the best rate of climb speed, Vx. In the IV=B9s that speed is approx. 135 kts. That=B9s a big difference. I also know from my sailplane racing days that yo= u never want to be slower than the best glide speed when trying to maximize distance. The penalty for being too slow is much greater than the penalty for being too fast. So has anyone actually done some testing to determine the appropriateness of the 120 knot figure? I=B9m beginning to suspect that its really the speed at which you get the minimum sink rate. Isn=B9t 120 knots the reported figure for best angle of climb? Here=B9s another data point =AD the CAF=C9 test of the Legacy tested its best L/D as 135 kts =8B hmmm. The AOA indicator (that some have wisely installed =AD I haven=B9t) has a small =8Cx=B9 on the second bar from the yellow bars that=B9s reported to be the best L/D. How is that number calculated? Does the setup procedure determine th= e best glide point for that aircraft=B9s glide polar? And can someone with thi= s equipment perform a flight at the AOA angle of the =B3x=B2 and report back to u= s the indicated airspeed and approximated aircraft weight at the time of this reading?=20 The best solution would be to do some engine off glides at various speeds t= o track the sink rates at those speeds. Has anyone done this? Given the same situation as faced Shannon, I certainly would like to maximize my distance by flying the best speed for the conditions (wind, weight) and give myself the best chance at making it to a suitable landing spot. I think that we all need to armed with this knowledge to give us the confidence that we can make it to that next airport, or, not make it and choose a field or road instead. Hal Woodruff IV-P --B_3174654926_21249768 Content-type: text/html; charset="ISO-8859-1" Content-transfer-encoding: quoted-printable Re: [LML] Re: Shannon Knoepflein's Legacy Accident I’m really curious= as to what the real best L/D speed is for the Lancair IV’s and Legaci= es.  I was told in my training at the factory that the best glide speed= is approximately 120 knots (for the IV), knowing full well that this speed = is dependent on the weight of the aircraft.  I also remember someone te= lling me that best glide speed in any airplane is the same as the best rate = of climb speed, Vx.  In the IV’s that speed is approx. 135 kts. &= nbsp;That’s a big difference.  I also know from my sailplane raci= ng days that you never want to be slower than the best glide speed when tryi= ng to maximize distance.  The penalty for being too slow is much greate= r than the penalty for being too fast.  So has anyone actually done som= e testing to determine the appropriateness of the 120 knot figure?  I&#= 8217;m beginning to suspect that its really the speed at which you get the m= inimum sink rate.  Isn’t 120 knots the reported figure for best a= ngle of climb?  Here’s another data point – the CAFÉ= test of the Legacy tested its best L/D as 135 kts — hmmm.

The AOA indicator (that some have wisely installed – I haven’t)= has a small ‘x’ on the second bar from the yellow bars thatR= 17;s reported to be the best L/D.  How is that number calculated?  = ;Does the setup procedure determine the best glide point for that aircraft&#= 8217;s glide polar?  And can someone with this equipment perform a flig= ht at the AOA angle of the “x” and report back to us the indicat= ed airspeed and approximated aircraft weight at the time of this reading?
The best solution would be to do some engine off glides at various speeds t= o track the sink rates at those speeds.  Has anyone done this?

Given the same situation as faced Shannon, I certainly would like to maximi= ze my distance by flying the best speed for the conditions (wind, weight) an= d give myself the best chance at making it to a suitable landing spot.  = ;I think that we all need to armed with this knowledge to give us the confid= ence that we can make it to that next airport, or, not make it and choose a = field or road instead.

Hal Woodruff
IV-P --B_3174654926_21249768--