X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 28 Jan 2013 09:50:03 -0500 Message-ID: X-Original-Return-Path: Received: from nm4-vm0.bullet.mail.ne1.yahoo.com ([98.138.90.253] verified) by logan.com (CommuniGate Pro SMTP 6.0.1) with ESMTPS id 6032867 for lml@lancaironline.net; Mon, 28 Jan 2013 09:44:52 -0500 Received-SPF: none receiver=logan.com; client-ip=98.138.90.253; envelope-from=chris_zavatson@yahoo.com Received: from [98.138.226.176] by nm4.bullet.mail.ne1.yahoo.com with NNFMP; 28 Jan 2013 14:44:16 -0000 Received: from [98.138.89.160] by tm11.bullet.mail.ne1.yahoo.com with NNFMP; 28 Jan 2013 14:44:16 -0000 Received: from [127.0.0.1] by omp1016.mail.ne1.yahoo.com with NNFMP; 28 Jan 2013 14:44:16 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 744043.21367.bm@omp1016.mail.ne1.yahoo.com Received: (qmail 76516 invoked by uid 60001); 28 Jan 2013 14:44:16 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:X-Rocket-MIMEInfo:X-Mailer:References:Message-ID:Date:From:Reply-To:Subject:To:MIME-Version:Content-Type; b=ZIAqVvfkwiANwucUzrl+SPrtwcUdh+u39Uo73dqujwLWlLZkhzJ6/vXArzSMvZfzsl6GskE3sLd3U38nAvFNl6xG0DxlmmYhhvOhqpHjMfmxwfg4zLoUPEigtSbQSaum6+LnVWZBzPCB0kHWofJXw6+oRfp6kxvxAL/fxi2iuFI= ; X-YMail-OSG: m9pxsnwVM1lGxvZGaMyjynjdDb.1KpHYbrkayZgVxHaeaZX SVX9MKJEOOpXs1HBP_6cz7vFcuXfH2845Tfu2DXmwYWLB_g1jELQDQh_mexW 3EHk__ygH0XKW9UiGEo8nSUZyuMYbS6NUEvtop5CP0Of6_Fqui9u3oL5raN9 zBB5ozzi58On0aBMcNZwmGAq5250njN8grF2aO39BF8L7N8CH5Nb0xbq5TEc QKKtVsq9HaGqZ1wZxbQbNkHUFAhRniJ4quj5yh5JlhnSWtFBN9qBPh4QX6QG F44.C7aoEymXZ3geNuT.Ca2_A9J0YorF2ooMJWAkblFadFoWjT4sZAKOeaep XJ6LFRIpSfHNQ.5qdf_NItUhjvGhfPmnoWVayBYitmKegU0Yn0IcPQX3ZQG8 S23UZ5xTmrwwv0N3d1hdeZHd.NTNF6nAvrIpuZPDVCuzYVfeLPW.BGNNuG7K rG0DznOge6hG_ns60.KTgYVtII34AX7w3phcbgmC4_GC_GMYoFyQyrS90zex zKVG9bpDGxqkrphfB9zxfrRr2Kfz80afKnqfAsGH6KpkMtBda6rNmg4F4axt EzEc- Received: from [76.246.36.168] by web121605.mail.ne1.yahoo.com via HTTP; Mon, 28 Jan 2013 06:44:16 PST X-Rocket-MIMEInfo: 001.001,RnJlZCwKVmVyeSBuaWNlIHdyaXRlIHVwLgpGYW5hdGljPyBZZXMKV2hhdCB0aW1pbmchCkZvciB1bnJlbGF0ZWQgcmVzZWFyY2gsIE45MUNawqBoYXBwZW5zIHRvIGJlwqBsb2FkZWQgdXAgd2l0aCBjYWxpYnJhdGVkIGluc3RydW1lbnRhdGlvbiBhbmQgZGF0YSBhY3F1aXNpdGlvbiBlcXVpcG1lbnQuwqAgVGhlwqBwdXJwb3NlwqB3YXPCoHRvIGdlbmVyYXRlwqBjb21wbGV0ZSBkcmFnIHBvbGFyc8KgZm9yIGRpZmZlcmVudCBjb25maWd1cmF0aW9ucyBhbG9uZyB3aXRowqBzb21lIFMmQyBwYXJhbWV0ZXJzLgoBMAEBAQE- X-Mailer: YahooMailWebService/0.8.131.499 References: X-Original-Message-ID: <1359384256.71622.YahooMailNeo@web121605.mail.ne1.yahoo.com> X-Original-Date: Mon, 28 Jan 2013 06:44:16 -0800 (PST) From: Chris Zavatson Reply-To: Chris Zavatson Subject: Re: [LML] How Slick Is Your Airplane? (PDF attached) X-Original-To: Lancair Mailing List MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="2053635335-1045084408-1359384256=:71622" --2053635335-1045084408-1359384256=:71622 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Fred,=0AVery nice write up.=0AFanatic? Yes=0AWhat timing!=0AFor unrelated r= esearch, N91CZ=A0happens to be=A0loaded up with calibrated instrumentation = and data acquisition equipment.=A0 The=A0purpose=A0was=A0to generate=A0comp= lete drag polars=A0for different configurations along with=A0some S&C param= eters.=0A=A0=A0=0ASome of the=A0points you made can't be emphasized enough = when it comes to collecting this sort of data.=0A=A0=0A-Settling times to r= each steady state speed (high speed end of the envelope)=A0is longer than w= hat one=A0might think.=A0 It is very difficult -if not=A0impossible-=A0to d= iscern a 1 knot change in speed over the period of a minute - well perhaps = with a digital readout in tenths of a knot.=A0 I found two minutes to be to= o short.=A0 The data showed three minutes to be=A0an acceptable=A0minimum.= =A0 Three minutes is also=A0suggested in some test flight texts.=A0 At low = speed (<100 KIAS), where induced drag is high, speed converges much more qu= ickly - not applicable however for these full power flat plate drag runs.= =0A=A0=0A-Atmospheric disturbances will scatter your data.=A0 If the autopi= lot is holding altitude=A0yet the airspeed is fluctuating, the atmosphere i= s not steady or has some vertical=A0component to its movement.=A0It takes s= ome patience to find the right conditions.=0A=A0=0A-The sensitivity to erro= r is indeed very large.=A0=A0Aircraft Instruments will have some=A0amount o= f error. Acceptable for use in aircraft operation perhaps, not so much in = drag measurements.=A0 MP is the worst I have seen in terms of percentage er= ror.=A0 Next come altimeter and the ASI.=A0 =0A=A0=0A-Altitude must be held= precisely.=A0 Descents or climbs of even 10's of fpm will throw the result= s off.=0A=A0=0A-Unless all your data is recorded automatically, take anothe= r set of eyes with you.=0A=A0=0ANow everyone have some fun collecting data!= =0A=A0=0AChris Zavatson=0AN91CZ=0A360std=0Ahttp://www.n91cz.net/=0A=A0=0A= =A0 =0A=A0=0A=0A=A0 =0A=0A________________________________=0A From: Frederi= ck Moreno =0ATo: lml@lancaironline.net =0ASent= : Friday, January 25, 2013 5:23 AM=0ASubject: [LML] How Slick Is Your Airpl= ane? (PDF attached)=0A =0A =0A=0A=0AMake some careful test flights and fol= low the instructions in the attached paper, and you can make a reasonably g= ood estimate. =0A=0A=0AFred Moreno =0A-- For archives and unsub http:= //mail.lancaironline.net:81/lists/lml/List.html --2053635335-1045084408-1359384256=:71622 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
Fred,
Very nice write up.
Fanatic?=0A Yes
What timing!
For unrelated research, N91= CZ happens to be loaded up with calibrated instrumentation and da= ta acquisition equipment. = The purpose was to generate complete drag polars = for different configurations along with some S&C parameters.
 &n= bsp;
Some of the points= you made can't be emphasized enough when it comes to collecting this sort = of data.
 
-Settling times to reach steady state speed (h= igh speed end of the envelope) is longer than what one might thin= k.  It is very difficult -if not impossible- to discern a 1 = knot change in speed over the period of a minute - well perhaps with a digi= tal readout in tenths of a knot.  I found two minutes to be too short.=   The data showed three minutes to be an acceptable minimum.=   Three minutes is also suggested in some test flight texts. = ; At low speed (<100 KIAS), where induced drag is high, speed converges = much more quickly - not applicable however for these full power flat=0A pla= te drag runs.
 
-Atmospher= ic disturbances=0A will scatter your data.  If the autopilot is holding altitude yet the airspee= d is fluctuating, the atmosphere is not steady or has some vertical co= mponent to its movement. It takes some patience to find the right cond= itions.
 
-The sens= itivity to error is indeed very large.  Aircraft Instruments will have some&n= bsp;amount of error. Acceptable for use in aircraft operation perhaps, not= so much in drag measurements.  MP is the worst I have seen in terms o= f percentage error.  Next come altimeter and the ASI. 
 
-Altitud= e must be held precisely.  Descents or climbs of even 10's of fpm will= throw the results off.
&= nbsp;
-Unless all your data is recorded automatically= , take another set of eyes with you.=
 
Now everyone have some fun collecting data!
 
Chris Zavatson
N91CZ
360std<= /span>
 
 
 

&n= bsp;
=
From: Frederick Moreno=0A <frederickm= oreno@bigpond.com>
To:<= /b> lml@lancaironline.net
Sent:<= /span> Friday, January 25, 2013 5:23 AM
Subject: [LML] How Slick Is Your Airplane? (PDF attac= hed)
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=0A =0A =0A=0A=0A=0A=0A=0A
=0A=0A=0A=0A=0A=0A=0A
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Make some careful test flights and follow the instruc= tions in the attached paper, and you can make a reasonably good estimate. <= /div>
=0A
=0A
=0A
=0A
&n= bsp;
=0A
Fred Moreno
=0A=0A=0A=0A
=
-- For= archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html
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