X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 02 Jan 2014 11:09:33 -0500 Message-ID: X-Original-Return-Path: Received: from p3plsmtpa06-02.prod.phx3.secureserver.net ([173.201.192.103] verified) by logan.com (CommuniGate Pro SMTP 6.0.8) with ESMTP id 6665705 for lml@lancaironline.net; Thu, 02 Jan 2014 10:31:21 -0500 Received-SPF: none receiver=logan.com; client-ip=173.201.192.103; envelope-from=jayph@fastairplane.net Received: from shuriken ([69.92.48.82]) by p3plsmtpa06-02.prod.phx3.secureserver.net with id 93Wl1n0091mPo4M013WlUl; Thu, 02 Jan 2014 08:30:46 -0700 From: "Jay Phillips" X-Original-To: "'Lancair Mailing List'" References: In-Reply-To: Subject: RE: [LML] Legacy Takeoff Performance at High Elevation Airports? X-Original-Date: Thu, 2 Jan 2014 08:30:47 -0700 X-Original-Message-ID: <02a501cf07cf$9c8c7870$d5a56950$@fastairplane.net> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_02A6_01CF0794.F02E63C0" X-Mailer: Microsoft Outlook 14.0 Thread-Index: AQJF0U6P7eds4M73bLid0RrUG0EWF5mD+l2Q Content-Language: en-us This is a multipart message in MIME format. ------=_NextPart_000_02A6_01CF0794.F02E63C0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Valin, I have a Legacy with a normally aspirated IO-550N based at KPRC, Prescott, AZ, field elevation of 5,100'. The main runway is 7,600' long, but I doubt I use more than half of it. The shortest runway is 4,400' and it is plenty long enough. I can't tell you what the takeoff roll is - don't really pay attention to that. Initial climb rates vary between 1,500 fpm and 2,500 fpm depending on temperature. I also have a turbocharged IV-P. It's performance is noticeably better than the normally aspirated Legacy, but the Legacy has plenty of power to get the job done. Jay Phillips From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Valin & Allyson Thorn Sent: Thursday, January 02, 2014 8:19 AM To: lml@lancaironline.net Subject: [LML] Legacy Takeoff Performance at High Elevation Airports? Hey LML gang, With an eye toward practicing instrument approaches, I downloaded the RealAir Lancair Legacy airplane model for Flight Simulator X. I'll send a separate LML post asking about its accuracy to focus that particular discussion. I was impressed, though, with its apparent flight performance fidelity in general. With our Legacy still under construction, it was interesting to fly the simulated Legacy out of our new airport base in Colorado at the Rocky Mountain Metro Airport (KBJC) near Boulder (former Jeffco) with a field elevation of about 5673 ft MSL. Fortunately the longest runway is about 9000 ft long. Even with that, if the Legacy sim model is fairly accurate, it has me concerned about takeoff performance especially during summers with density altitudes as high as around 9000 ft. With a naturally aspirated engine we'll be looking at only about 24" of manifold pressure at full throttle and the thinner air for the prop and wings... So my question is, what kind of takeoff performance are Legacy pilots seeing at high elevation airports - take off rollout, climb rates, etc.? This has us thinking about at least turbo-normalizing our IO-550 engine. For those with turbo-chargers, what kind of improvement in performance are you seeing at high elevation airports? Also, how are pilots adjusting their takeoff technique at high elevations. In comparing the sim Legacy at sea level and in Colorado, and being on the back side of the power curve below about 120 kts, it helps to delay take off rotation speed at high elevation in the sim. Real world.? Thanks, Valin Thorn Legacy Project Boulder, Colorado ------=_NextPart_000_02A6_01CF0794.F02E63C0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Valin,

 

I have a Legacy with a = normally aspirated IO-550N based at KPRC, Prescott, AZ, field elevation = of 5,100’. The main runway is 7,600’ long, but I doubt I use = more than half of it. The shortest runway is 4,400’ and it is = plenty long enough. I can’t tell you what the takeoff roll is = – don’t really pay attention to that. Initial climb rates = vary between 1,500 fpm  and 2,500 fpm depending on temperature. I = also have a turbocharged IV-P. It’s performance is noticeably = better than the normally aspirated Legacy, but the Legacy has plenty of = power to get the job done.

 

Jay = Phillips

 

From:= = Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of = Valin & Allyson Thorn
Sent: Thursday, January 02, 2014 = 8:19 AM
To: lml@lancaironline.net
Subject: [LML] = Legacy Takeoff Performance at High Elevation = Airports?

 

Hey LML = gang,

 

With an eye toward practicing = instrument approaches, I downloaded the RealAir Lancair Legacy airplane = model for Flight Simulator X.  I’ll send a separate LML post = asking about its accuracy to focus that particular discussion.  I = was impressed, though, with its apparent flight performance fidelity in = general.

 

With our Legacy still under = construction, it was interesting to fly the simulated Legacy out of our = new airport base in Colorado at the Rocky Mountain Metro Airport (KBJC) = near Boulder (former Jeffco) with a field elevation of about 5673 ft = MSL.  Fortunately the longest runway is about 9000 ft long.  = Even with that, if the Legacy sim model is fairly accurate, it has me = concerned about takeoff performance especially during summers with = density altitudes as high as around 9000 ft.  With a naturally = aspirated engine we’ll be looking at only about 24“ of = manifold pressure at full throttle and the thinner air for the prop and = wings...

 

So my question is, what kind of = takeoff performance are Legacy pilots seeing at high elevation airports = – take off rollout, climb rates, etc.?  This has us thinking = about at least turbo-normalizing our IO-550 engine…  For = those with turbo-chargers, what kind of improvement in performance are = you seeing at high elevation airports?

 

Also, how are pilots adjusting their = takeoff technique at high elevations.  In comparing the sim Legacy = at sea level and in Colorado, and being on the back side of the power = curve below about 120 kts, it helps to delay take off rotation speed at = high elevation in the sim.  Real world…?  =

 

Thanks,

 

Valin Thorn

Legacy = Project

Boulder, = Colorado

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