X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 29 Dec 2011 14:04:42 -0500 Message-ID: X-Original-Return-Path: Received: from hrndva-omtalb.mail.rr.com ([71.74.56.123] verified) by logan.com (CommuniGate Pro SMTP 5.4.3) with ESMTP id 5330298 for lml@lancaironline.net; Thu, 29 Dec 2011 10:24:27 -0500 Received-SPF: none receiver=logan.com; client-ip=71.74.56.123; envelope-from=Wolfgang@MiCom.net X-Original-Return-Path: X-Authority-Analysis: v=2.0 cv=Pb19d1dd c=1 sm=0 a=MHZY6FYWMEQOp7S43i2QIw==:17 a=ttCsPuSJ-FAA:10 a=Ia-xEzejAAAA:8 a=Tabk1mwkIBOSLw9g7SwA:9 a=pWU0A4YR33P5pFFcelQA:7 a=wPNLvfGTeEIA:10 a=EzXvWhQp4_cA:10 a=5ZGAaHfJsDH6dKm5:21 a=oGGjN0ze_3P631rJ:21 a=69EAbJreAAAA:8 a=PUFxO3vXzEroAzmfNdoA:9 a=aE8_juHmXgyu-JXGc5cA:7 a=EfJqPEOeqlMA:10 a=ufMm2Fw84v8SaQSh:21 a=_zezmOBXmRy9KSjn:21 a=MHZY6FYWMEQOp7S43i2QIw==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.218.201.50 Received: from [74.218.201.50] ([74.218.201.50:1188] helo=lobo) by hrndva-oedge04.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTP id 53/AC-10702-7068CFE4; Thu, 29 Dec 2011 15:23:51 +0000 X-Original-Message-ID: <006201ccc63d$db5a61a0$6401a8c0@lobo> From: "Wolfgang" X-Original-To: Subject: Fw: Performance specs X-Original-Date: Thu, 29 Dec 2011 10:23:45 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_005F_01CCC613.F24B2130" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_005F_01CCC613.F24B2130 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable The calculations get a bit involved when trying to calculate = performance, not just one metric, for altitude. Holding the brakes on take off only lets you have full power for the = entire take off roll and not be rolling initially without full power. I = don't see where that shortens the take off roll that much. Depends on = how slow you are on throttle up. Brakes for the first part of throtle up = will be helpfull when necessary. For the shortest take off roll, you have to lift off at a lower than = usual air speed. Rotating at Vx can do that. However, the slower you = fly, the "mushier" it flys. You do ot get "responsive" handling untill = you get past Vy, the most efficient angle of attack. If you loose power = at or below those speeds, you have little margin for recovery. Now the hard part. you will have to calculate the increased take off = roll to get to the increased air speed for lift off at the reduced = density with reduced power coming fron the engine. A simple way would be = to calculate your sea level acceleration to take off using empherical = data and do a linear reduction on acceleration proportional to the = density altitude difference along with the base line take off air speed = divided by the square root of the density difference to get the = increased take off air speed needed. Once you have the increased time to = get to the increased speed, you can calculate the increased ground roll. = Wolfgang ----- Original Message -----=20 From: Jim Scales=20 To: lml@lancaironline.net=20 Sent: Saturday, December 24, 2011 1:04 PM Subject: Performance specs -------------------------------------------------------------------------= ----- Guys, I am trying to tweak my Super ES performance information and would = like your input on a couple of things. I want to put together some charts/tables that let me calculate my = plane's performance relative to density altitude. The purpose of this = information gathering exercise is to put together a chart that can use = realistic numbers to help me calculate performance at higher elevations = and density altitudes. I want to do some flying out west and feel my = tools are lacking where performance calculations for my plane are = concerned. I have been able to gather quite a bit of info over the years of = flying my ES concerning climb rate, cruise, percentage of HP, as they = are affected by density altitude. These seem pretty clear. My gray area is take-off distance. I have never actually done my own = tests in this area other than paying attention at my home airport about = where down the runway I start flying. If any of you have actual numbers = for your ES I would like to see them if you don't mind. Consensus of information that I found on the internet and in Lancair = publications seems to be about a 700 ft ground roll on a standard day at = sea level for 3400 pound gw. This number appears unrealistic to me.=20 The standard procedure that I have seen in a couple of places seems to = require lifting the nose wheel around 55 and climbing at 85. Doesn't = mention holding brakes till full power. Can't seem to find information = that indicates when this method causes the plane to break ground. (Might = be the 700 feet that is mentioned). This strikes me as an aggressive = method (might not be, just seems so to me given my experience in my = plane). I am not a test pilot and have no intention of flying at what = might be the edge of the envelope. I prefer a bit of a conservative = number, whatever it might be. I have tried this method on a few occasions and I find it somewhat = uncomfortable because the plane tends to settle in a tail low attitude = after becoming airborne and seems quite lazy even while still in ground = effect. I prefer crisp performance and firm response to control inputs. = The 55/85 process doesn't seem to fit these preferences. My method involves 10 degrees of flaps, deliberate, but not speedy, = application of power, slight back pressure on stick beginning about 65, = holding that pressure until plane flies off. Usually flying occurs at = about 85-90 with no "sag" feeling and very positive control response. = Climb out is at 100 till 400 feet then 125-130 to altitude. =20 On an approximately standard day this results in wheels off the runway = at about 900 feet at about 3200 pounds. At gross of 3400 the number is = about 1100. Again I have done no actual measurements, just judging by = the thousand foot marks on the runway. I discovered the Koch Chart and found it to be really useful but it is = all based on a fairly accurate standard day gross weight ground roll. So is it possible to put together a chart that can help me figure = ground roll and climb rate for various gross weight situations? Is one = already available that I just don't know about? The Koch Chart only = requires ground roll and climb rate for performance calculations = relative to density altitude. Being a flatlander I have not ever been that concerned about this = subject. Always had plenty of runway and lots of horsepower. I don't = want to be that "loose" in my calculations when I encounter high density = altitude situations. I prefer to know what to expect as far as airplane = performance is concerned. I am probably not able to adequately explain what it is that I am = searching for. I believe my primary need is a realistic standard day = gross weigh ground roll number that can be safely used to calculate = density altitude take off performance. Hopefully some of you can gather = from what I have written what else you think I need. I appreciate any input you might have on this subject. I have not = seen this subject on LML so maybe I am not the only one who could use = this information. Just trying to be safe. Thanks, Jim Scales (almost 1200 hours and very happy) ------=_NextPart_000_005F_01CCC613.F24B2130 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
The calculations get a bit involved when trying = to=20 calculate performance, not just one metric, for altitude.
 
Holding the brakes on take off only lets you = have full=20 power for the entire take off roll and not be rolling initially without = full=20 power. I don't see where that shortens the take off roll that much. = Depends on=20 how slow you are on throttle up. Brakes for the first part of throtle up = will be=20 helpfull when necessary.
 
For the shortest take off roll, you have to lift = off at a=20 lower than usual air speed. Rotating at Vx can do that. However, the = slower you=20 fly, the "mushier" it flys. You do ot get "responsive" handling untill = you get=20 past Vy, the most efficient angle of attack. If you loose power at = or below=20 those speeds, you have little margin for recovery.
 
Now the hard part. you will have to calculate = the=20 increased take off roll to get to the increased air speed for lift off = at the=20 reduced density with reduced power coming fron the engine. A simple way = would be=20 to calculate your sea level acceleration to take off using empherical = data and=20 do a linear reduction on acceleration proportional to the density = altitude=20 difference along with the base line take off air speed divided by the = square=20 root of the density difference to get the increased take off air speed = needed.=20 Once you have the increased time to get to the increased speed, you = can=20 calculate the increased ground roll. 
 
Wolfgang
 
 
----- Original Message -----
From:=20 Jim=20 Scales
Sent: Saturday, December 24, = 2011 1:04=20 PM
Subject: Performance = specs





Guys,

I am trying to tweak my Super ES performance information and = would like=20 your input on a couple of things.

I want to put together some charts/tables that let me calculate = my=20 plane's performance relative to density altitude. The purpose of = this=20 information gathering exercise is to put together a chart that can use = realistic numbers to help me calculate performance at higher = elevations and=20 density altitudes.  I want to do some flying out west and feel my = tools=20 are lacking where performance calculations for my plane are = concerned.

I have been able to gather quite a bit of info over the years of = flying=20 my ES concerning climb rate, cruise, percentage of HP, as they are = affected by=20 density altitude.  These seem pretty clear.

My gray area is take-off distance.  I have never actually = done my=20 own tests in this area other than paying attention at my home airport = about=20 where down the runway I start flying. If any of you have actual = numbers for=20 your ES I would like to see them if you don't mind.

Consensus of information that I found on the internet and in = Lancair=20 publications seems to be about a 700 ft ground roll on a standard day = at sea=20 level for 3400 pound gw.  This number appears unrealistic to=20 me. 

The standard procedure that I have seen in a couple of places = seems to=20 require lifting the nose wheel around 55 and climbing at 85. =  Doesn't=20 mention holding brakes till full power.  Can't seem to find = information=20 that indicates when this method causes the plane to break ground. = (Might be=20 the 700 feet that is mentioned). This strikes me as an aggressive = method=20 (might not be, just seems so to me given my experience in my plane). =  I=20 am not a test pilot and have no intention of flying at what might be = the edge=20 of the envelope.  I prefer a bit of a conservative number, = whatever it=20 might be.

I have tried this method on a few occasions and I find it = somewhat=20 uncomfortable because the plane tends to settle in a tail low attitude = after=20 becoming airborne and seems quite lazy even while still in ground = effect.=20  I prefer crisp performance and firm response to control inputs. = The=20 55/85 process doesn't seem to fit these preferences.

My method involves 10 degrees of flaps, deliberate, but not = speedy,=20 application of power, slight back pressure on stick beginning about = 65,=20 holding that pressure until plane flies off.  Usually flying = occurs at=20 about 85-90 with no "sag" feeling and very positive control response. = Climb=20 out is at 100 till 400 feet then 125-130 to altitude.  

On an approximately standard day this results in wheels off the = runway at=20 about 900 feet at about 3200 pounds.  At gross of 3400 the number = is=20 about 1100.  Again I have done no actual measurements, just = judging by=20 the thousand foot marks on the runway.

I discovered the Koch Chart and found it to be really useful but = it is=20 all based on a fairly accurate standard day gross weight ground = roll.

So is it possible to put together a chart that can help me figure = ground=20 roll and climb rate for various gross weight situations?  Is one = already=20 available that I just don't know about?  The Koch Chart only = requires=20 ground roll and climb rate for performance calculations relative to = density=20 altitude.

Being a flatlander I have not ever been that concerned about this = subject.  Always had plenty of runway and lots of horsepower. =  I=20 don't want to be that "loose" in my calculations when I encounter high = density=20 altitude situations.  I prefer to know what to expect as far as = airplane=20 performance is concerned.

I am probably not able to adequately explain what it is that I am = searching for.  I believe my primary need is a realistic standard = day=20 gross weigh ground roll number that can be safely used to calculate = density=20 altitude take off performance.  Hopefully some of you can gather = from=20 what I have written what else you think I need.

I appreciate any input you might have on this subject.  I = have not=20 seen this subject on LML so maybe I am not the only one who could use = this=20 information.

Just trying to be safe.

Thanks,

Jim Scales  (almost 1200 hours and very happy)



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