X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 17 Sep 2013 16:40:54 -0400 Message-ID: X-Original-Return-Path: Received: from mail9.tpgi.com.au ([203.12.160.104] verified) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTPS id 6479310 for lml@lancaironline.net; Tue, 17 Sep 2013 16:25:31 -0400 Received-SPF: pass receiver=logan.com; client-ip=203.12.160.104; envelope-from=domcrain@tpg.com.au X-TPG-Antivirus: Passed X-TPG-Abuse: host=60-241-193-89.static.tpgi.com.au; ip=60.241.193.89; date=Wed, 18 Sep 2013 06:24:52 +1000 Received: from [192.168.0.3] (60-241-193-89.static.tpgi.com.au [60.241.193.89]) by mail9.tpgi.com.au (envelope-from domcrain@tpg.com.au) (8.14.3/8.14.3) with ESMTP id r8HKOLt0005533 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO) for ; Wed, 18 Sep 2013 06:24:52 +1000 From: "Dominic V. Crain" Content-Type: multipart/alternative; boundary="Apple-Mail=_DC762F71-542F-4B27-A304-4403A7CE816E" X-Original-Message-Id: Mime-Version: 1.0 (Mac OS X Mail 6.5 \(1508\)) Subject: Re: [LML] Re: Lancair 320/360 performance and stability X-Original-Date: Wed, 18 Sep 2013 06:24:21 +1000 References: X-Original-To: "Lancair Mailing List" In-Reply-To: X-Mailer: Apple Mail (2.1508) --Apple-Mail=_DC762F71-542F-4B27-A304-4403A7CE816E Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Hi Scott and Chris, Ignoring the other variables, what effect on speed performance do you = think the small tailed 320 has, given the same power supply. Cheers Dom Dominic V. Crain domcrain@tpg.com.au Phone 03-94161881 Mobile 0412-359320 On 18/09/2013, at 5:35 AM, Sky2high@aol.com wrote: > Chris, > =20 > You're talking to GrayHAWK, not Al Batross. I.E. (from Wikipedia):=20 > High aspect ratio wings abound in nature. Most birds that fly long = distances have wings of high aspect ratio, and with tapered or = elliptical wingtips. This is particularly noticeable on soaring birds = such as albatrosses and eagles. By contrast, hawks ... have wings of low = aspect ratio ... for maneuverability. >=20 > Everything is aviation is a compromise. > =20 > I hope a small tailed 360 steps up. > =20 > Scott > =20 > =20 > In a message dated 9/17/2013 2:18:50 P.M. Central Daylight Time, = chris_zavatson@yahoo.com writes: > Scott, > Thanks. Examining the 360 (MkII) performance and characteristics in = greater detail as been very interesting. > =20 > The small tail has a very low aspect ratio and may indeed be subject = to higher drag if the stabilizer incidence requires significant elevator = input to trim. The MkII tail adds about 2 sqft, but more significantly = has a much greater aspect ratio. My stab was well aligned for the sweep = of flap settings as the elevator deflection was about 0.5 degrees TE = down. In fact, all of the points were inside of 0.1 degrees of elevator = movement.=20 > The concept of aft CG being more efficient is by reducing trim drag. = It is used quite successfully in aircraft that adjust the entire = stabilizer for trim. A fixed stab angle that is too far from neutral in = the aft CG or in the 'super-reflexed' cruise condition could negate any = benefit. In my case the plot of flap setting vs. airspeed showed that I = had not yet reached a peak. Extrapolating the curve gives me another 2 = kts at 12 degrees reflex. Extrapolating is a bit dangerous with any = polynomial curve, but on the other hand this one has an exceptionally = well behaved 2nd order trend. -7 degrees certainly provides a large = portion of the benefit. > It would be very interesting to run through the same series of tests = with a small tail at the same static margins for a side by side = comparison. > Chris =20 > =20 > Chris Zavatson > N91CZ > 360std > http://www.n91cz.net/ >=20 > =20 > From: "Sky2high@aol.com" > To: lml@lancaironline.net=20 > Sent: Sunday, September 15, 2013 12:26 PM > Subject: [LML] Re: Lancair 320/360 performance and stability >=20 > Chris, > =20 > Great research. > =20 > In my small tailed 320, increased flap reflex experimentation did not = result in increased top end speed. The nose up pitch was increased, = requiring increased nose down trim - probably resulting in greater = empennage drag negating any reduction in drag from the greater reflex. = Of course, we would have to discuss the angle of incidence of the small = tail and its relationship to the elevator correcting for nose down = pitching ( my incidence was at -.9 degrees). > =20 > By moving weights forward and aft in the same flight, forward CG was = better for maximizing speed - unlike some aircraft that see max speed = when the CG is at the neutral point, probably a consequence of more = standard wing/tail design that saw drag from wing/horizontal +/- lift = factors more balanced and minimized. > =20 > For me, the biggest gain in speed came from adding $140 worth of gap = seals to both sides of all control surface and the flaps (remember = Greenameyer made his flaps part of the wing in his very fast Reno Legacy = - he didn't need no stink'n flaps). I believe that I lost no speed when = I removed the upper seals from the flaps last year. The seals were = curved Mylar seals often obtainable for gliders. The gain was from 6 to = 8 KIAS, depending. Controls were more responsive and the wee rudder was = effective about 5 KIAS sooner. > =20 > I didn't follow up on a cockpit controlled diffuser for managing = cooing drag as I saw about 7" H2O upper to lower cowl at about 135 KIAS = (climb speed), but 13" at 200 KIAS and such pressure was not necessary = as the engine ran cool there. > =20 > I found the small tail had enough control - I only wanted my little = engine to pull everything along as quickly as possible. > =20 > Scott Krueger > =20 > In a message dated 9/13/2013 7:32:54 A.M. Central Daylight Time, = chris_zavatson@yahoo.com writes: > N91CZ has been a flying laboratory for most of this year. Below are = links to three reports that may be of interest to the Lancair community, = in particular 320/360 flyers. > =20 > The first takes a look at the effect flap position has on total = aircraft drag using the NLF(1)-0215. The numbers are quite impressive = in terms of drag coefficients. In the end, it looks like we could = benefit from a little more reflex beyond -7 degrees. > http://n91cz.com/Performance/Cruise_Flap_Report.pdf > =20 > The second report looks at the neutral point differences and static = margins of the small and large tail 320/360 models. A large portion of = the document is a tutorial of sorts on longitudinal stability. It deals = only with static stability, but is a good lead-in to the third report. > http://n91cz.com/Stability/Lancair360_Static_Stability.pdf > =20 > The third report looks at the stability of the 360 MKII in much = greater detail. It include dynamic stability in both cruise and landing = configurations, as well as, stick force gradients and elevator = effectiveness all the way down to stall speed. > = http://n91cz.com/Stability/Lancair360_Stability_and_Control_Evaluation.pdf= > =20 > =20 > Chris Zavatson > N91CZ > 360std > http://www.n91cz.net/ >=20 >=20 > -- > For archives and unsub = http://mail.lancaironline.net:81/lists/lml/List.html >=20 >=20 --Apple-Mail=_DC762F71-542F-4B27-A304-4403A7CE816E Content-Transfer-Encoding: 7bit Content-Type: text/html; charset=us-ascii Hi Scott and Chris,

Ignoring the other variables, what effect on speed performance do you think the small tailed 320 has, given the same power supply.

Cheers

Dom

Dominic V. Crain
Phone 03-94161881
Mobile 0412-359320

On 18/09/2013, at 5:35 AM, Sky2high@aol.com wrote:

Chris,
 
You're talking to GrayHAWK, not Al Batross.  I.E. (from Wikipedia): 

High aspect ratio wings abound in nature. Most birds that fly long distances have wings of high aspect ratio, and with tapered or elliptical wingtips. This is particularly noticeable on soaring birds such as albatrosses and eagles. By contrast, hawks ... have wings of low aspect ratio ... for maneuverability.

Everything is aviation is a compromise.
 
I hope a small tailed 360 steps up.
 
Scott
 
 
In a message dated 9/17/2013 2:18:50 P.M. Central Daylight Time, chris_zavatson@yahoo.com writes:
Scott,
Thanks.  Examining the 360 (MkII) performance and characteristics in greater detail as been very interesting.
 
The small tail has a very low aspect ratio and may indeed be subject to higher drag if the stabilizer incidence requires significant elevator input to trim.  The MkII tail adds about 2 sqft, but more significantly has a much greater aspect ratio.  My stab was well aligned for the sweep of flap settings as the elevator deflection was about 0.5 degrees TE down.  In fact, all of the points were inside of 0.1 degrees of elevator movement. 
The concept of aft CG being more efficient is by reducing trim drag.  It is used quite successfully in aircraft that adjust the entire stabilizer for trim.  A fixed stab angle that is too far from neutral in the aft CG or in the 'super-reflexed' cruise condition could negate any benefit.  In my case the plot of flap setting vs. airspeed showed that I had not yet reached a peak.  Extrapolating the curve gives me another 2 kts at 12 degrees reflex.  Extrapolating is a bit dangerous with any polynomial curve, but on the other hand this one has an exceptionally well behaved 2nd order trend.   -7 degrees certainly provides a large portion of the benefit.
It would be very interesting to run through the same series of tests with a small tail at the same static margins for a side by side comparison.
Chris   
 
Chris Zavatson
N91CZ
360std

 
From: "Sky2high@aol.com" <Sky2high@aol.com>
To: lml@lancaironline.net
Sent: Sunday, September 15, 2013 12:26 PM
Subject: [LML] Re: Lancair 320/360 performance and stability

Chris,
 
Great research.
 
In my small tailed 320, increased flap reflex experimentation did not result in increased top end speed.  The nose up pitch was increased, requiring increased nose down trim - probably resulting in greater empennage drag negating any reduction in drag from the greater reflex.  Of course, we would have to discuss the angle of incidence of the small tail and its relationship to the elevator correcting for nose down pitching ( my incidence was at -.9 degrees).
 
By moving weights forward and aft in the same flight, forward CG was better for maximizing speed - unlike some aircraft that see max speed when the CG is at the neutral point, probably a consequence of more standard wing/tail design that saw drag from wing/horizontal +/- lift factors more balanced and minimized.
 
For me, the biggest gain in speed came from adding $140 worth of gap seals to both sides of all control surface and the flaps (remember Greenameyer made his flaps part of the wing in his very fast Reno Legacy - he didn't need no stink'n flaps).  I believe that I lost no speed when I removed the upper seals from the flaps last year. The seals were curved Mylar seals often obtainable for gliders.  The gain was from 6 to 8 KIAS, depending.  Controls were more responsive and the wee rudder was effective about 5 KIAS sooner.
 
I didn't follow up on a cockpit controlled diffuser for managing cooing drag as I saw about 7" H2O upper to lower cowl at about 135 KIAS (climb speed), but 13" at 200 KIAS and such pressure was not necessary as the engine ran cool there.
 
I found the small tail had enough control - I only wanted my little engine to pull everything along as quickly as possible.
 
Scott Krueger
 
In a message dated 9/13/2013 7:32:54 A.M. Central Daylight Time, chris_zavatson@yahoo.com writes:
N91CZ has been a flying laboratory for most of this year.  Below are links to three reports that may be of interest to the Lancair community, in particular 320/360 flyers.
 
The first takes a look at the effect flap position has on total aircraft drag using the NLF(1)-0215.  The numbers are quite impressive in terms of drag coefficients.  In the end, it looks like we could benefit from a little more reflex beyond -7 degrees.
 
The second report looks at the neutral point differences and static margins of the small and large tail 320/360 models.  A large portion of the document is a tutorial of sorts on longitudinal stability.  It deals only with static stability, but is a good lead-in to the third report.
 
The third report looks at the stability of the 360 MKII in much greater detail.  It include dynamic stability in both cruise and landing configurations, as well as, stick force gradients and elevator effectiveness all the way down to stall speed.
 
 
Chris Zavatson
N91CZ
360std


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