X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 14 Jan 2008 12:46:58 -0500 Message-ID: X-Original-Return-Path: Received: from [64.12.143.100] (HELO imo-m12.mail.aol.com) by logan.com (CommuniGate Pro SMTP 5.2c4) with ESMTP id 2643432 for lml@lancaironline.net; Sun, 13 Jan 2008 13:05:11 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.143.100; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-m12.mx.aol.com (mail_out_v38_r9.3.) id q.be9.256b2769 (30738); Sun, 13 Jan 2008 13:04:27 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Sun, 13 Jan 2008 13:04:27 EST Subject: Re: [LML] Re: MKII tail vs original tail?? X-Original-To: lml@lancaironline.net X-Original-CC: domcrain@tpg.com.au MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1200247467" X-Mailer: Unknown sub 34 X-Spam-Flag: NO -------------------------------1200247467 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en Dom, =20 My hackles are in shackles. =20 I am not a test pilot (Hmmmmm, not trained anyway), but I stayed in a =20 Holiday Inn once. While the OZ analysis is true, there are ways to amelior= ate the=20 unfriendly small tail characteristics. Here are some thoughts gained over=20 850 hours behind the stick of a 320 and generally within a 100 feet of a=20 purposely hand held altitude in reasonably smooth air. =20 =20 1. Neutral to negative longitudinal stability confirmed. Recognize it,=20 understand it, deal with it (one way is with a larger tail, there are other= s). 2. Every Lancair 200/300 series is uniquely customized and details of =20 handling may differ while general characteristics could and should be under= stood. 3. Instrument approaches in smooth air are a moderate challenge and whilst =20 in turbulent air, they are more interesting. (I believe that is a quote fro= m=20 the Marquis de Sade shortly after he went flying in his 360.) =20 OK, here is a limited description of my components, customization and their= =20 consequences. a. Slow built 320, 1200 # empty weight and empty CG a hair forward of specs= . b. Properly installed bob-weight with the elevator bell crank arm reduced t= o=20 3" (stick throw reduced by 25%, forces increased from none to some). 60=20 degree banked (2G) full circle steep turns to the left with cruise trim unt= ouched=20 require far more than 7 lbs of pull to hold altitude (no opposite rudder)=20 and the need for the pull is quite delayed after first entering the turn. =20 Right turns require less force and and the need to apply the full holding f= orce=20 is delayed further than those steep turns to the left. Holding the altitud= e=20 within 50 feet throughout the 360 turn is a real challenge. 720 degree tur= ns=20 are easier because by then you've got it - until you hit your self induced=20 burble. Drat. c. I have the Reichel geared trim wheel with stronger springs to compensate= =20 for the shorter arm. In cruise, spring controlled trim characteristics add= =20 to the sensitivity in pitch because of the broad dead band of little spring= =20 force exerted at the trimmed position, thus the non-holding spring is relax= ed=20 and, if the plane is "balanced," even the hold spring is not pushing very=20 hard. In slow flight with flaps at some extension, the holding spring is u= nder=20 greater tension and the sensitivity is somewhat reduced. I cannot compare=20= my=20 flight characteristics to Lancairs equipped with tabbed-elevator trim =20 systems. d. My horizontal tail surfaces are thinner than the plans call for. Don't=20 ask. I don't know if there is a flight effect from that, but it is differe= nt=20 than the design. I also have gap seals with unknown effect on elevator/pit= ch=20 controlability. e. More forward CG results in a more stabilized pitch control. The rear=20 quarter of the CG range results in much less stability than the front half.= Be=20 aware of this when loading the plane. Lancair moved the CG forward 1.5=20 inches without a detrimental effect (3" longer engine mount to compensate f= or=20 added weight from the larger tail that moved the CG aftward). So, keep the= CG=20 more forward for better flights. =20 Observed behavior and/or techniques to compensate: i. Some have experienced an extreme nose bobbing when slipping at slow air =20 speeds. Try as I might, I could only induce gentle sinusoidal bobbing,=20 different from left or right (I don't remember which was more). Since I fl= y=20 differently than others (Don't we all?), I have little use for slip attitud= es until=20 just above the runway. If not on an instrument approach, slow down early,=20 fly a higher pattern, fly a steeper final descent angle, carefully control=20= the=20 speed (AOA has helped). ii. With respect to slow flight when nearing the airfield - in my airplane,= =20 throttle back and slow to 160 KIAS early, tick the flaps out of reflex =20 (resulting in rapid loss of airspeed and lowering the nose) and re-trim. A=20= =20 stabilized slow speed approach(110 to 120 KIAS) at low power with flaps at =20= the=20 takeoff position and everything trimmed is the most stabilized, comfortable= and=20 with the least workload. Final at 85-90 Kts. iii. The lack of longitudinal stability is a bummer during an approach: =20 Change of speed <=3D> change of attitude <=3D> change of descent rate. Not= e the=20 double pointed arrows. Instrument approach workload is increased when tryi= ng to=20 manage these. Turbulence does not assist the pilot.=20 iv. Gap seals have provided a benefit such that the rudder came alive at a=20 lower airspeed (maybe 5 to 10 Kts). I cannot say I noticed a difference wi= th=20 respect to the elevator. Gap seals are high maintenance items unless they=20 are built-in during construction. v. I cannot get my Lancair to enter a turn by applying strong rudder inputs=20= =20 (Hmmmm, maybe I only tested this at cruise speeds). In other words, I do n= ot=20 feel much, if any, roll tendencies from applying the rudder in level flight= =20 at cruise speeds. I don't remember if I had to compensate for roll in the=20 bobbing tests. The feel is different from left to right rudder. =20 The conclusion for me: Yes, in certain flight regimes where stability is=20 desirable, it would be nice to have that stability available by design. =20 Understanding your steed's characteristics can be useful if you remember to= take=20 those into account when flying. There are many experimental and aerobatic=20 planes extant that are twitchy - deal with them for they are not as forgivi= ng as=20 those designed to be fool-proof. =20 Possible conclusions for others: Man, this ain't no spam can. Experiences= =20 will vary. Learn it. Love it. Stay on your toes. Use O2 as needed. Pay=20 attention to Mother Nature. Occasionally look out the window. Don't do no= th'n=20 stoopid! =20 Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) Pilot not TSO'd, Certificated score only > 70%. =20 PS: Is it possible the CG range was originally computed from the =20 un-reflexed wing characteristics? That is, computed from the "normal" wing= shape and=20 thus set too far aft? =20 =20 =20 In a message dated 1/13/2008 7:31:02 A.M. Central Standard Time, =20 domcrain@tpg.com.au writes: =20 The recent comments regarding the Small v. Big tail draw my attention to th= e=20 fact that on a recent visit to the wide brown land up over, LML lister=20 Angier was privileged to see two examples of large tail Lancair's. One belo= nging=20 to me (didn=E2=80=99t build it), and the other being the example quoted in=20= the=20 attached letter to Rob Wolf=E2=80=99s post =E2=80=9CA look at Lancair 360 H= andling Qualities=E2=80=9D. Now=20 owned by another lister here.=20 The only Lancair=E2=80=99s I have handled in the air were all large tail ve= rsions,=20 with one exception, that being N5ZQ in the States. Bill will undoubtedly=20 recall that I was =E2=80=93 let=E2=80=99s say =E2=80=9Cropey=E2=80=9D =E2= =80=93 to say the least. While I am prepared to=20 accept that is my lack of skill, and I reflect long and hard on this after=20 each flight I have made over forty odd years, I do come to the conclusion t= hat=20 there is a distinct improvement in stability and handling of the Lancair=20 with the large tail.=20 Over the past few months =E2=80=93almost a year actually, there has been a=20= slow but=20 steady approach to the improvement of training of, and understanding by,=20 Lancair pilots here up over, brought on by the historical global accident r= ate,=20 and highlighted by two fatals within six days in Australia, 20 months ago.=20 A Lancair Pilot Group has been established, and having been asked to be=20 involved, I have sought advice from various sources regarding their views o= n the=20 matter of Lancair training and opinions on handling.=20 In this process I have had email discussions with the test pilot who=20 undertook some of the test flying on the Lancair which resulted in the=20 recommendation to enlarge the tail.=20 I quote from the email I received from one him on 20 September 2007:=20 =E2=80=9C=E2=80=A6=E2=80=A6.When the first example (a 320 I think?) was eva= luated, it was found to=20 have 2 major design problems/defects. First the aft CG condition was=20 unrealistic (in excess of 30% MAC), and the horizontal stabiliser was too s= mall. =20 Combined these resulted in neutral or negative stick free longitudinal =20 stability. Also manoeuvre stability (stick force per G) was at best measur= ed in=20 ounces per G. Standard comment from then owners was"I like it like that be= cause=20 it has fighter like feel." These pilots had obviously never flown a=20 fighter, at least not one built since about 1920, which all have positive l= ong stab,=20 and minimum stick forces of about 7 lb/G. =20 CASA insisted (under the good/bad old 101.28 rule) that stability be=20 improved. I think the aft CG limit was moved forward (not sure how much) a= nd bigger=20 tails were required. The bigger tails (2 local REG 35 solutions by Graham=20 Swannel and Dave Simons) produced adequate solutions, but the practicalitie= s=20 of keeping CG forward remained. The Lancair 235/230/360 models also have=20 negative lateral sideslip stability; with a low wing and no dihedral the=20 predominant rolling force in a sideslip is due to the rudder. This charact= eristic=20 is rarely seen, and is disturbing when deliberately sideslipping during cro= ss=20 wind approaches. For IFR approval, CASA insisted this be fixed and a=20 rudder/aileron interconnect was developed (I think by Dave Simons) which pr= oduced=20 apparent lateral sideslip stability and hence predictable handling qualitie= s in=20 sideslip.=20 The kit manufacturer was not amused by these criticisms of his creation and= =20 refused to have anything to do with them. However, shortly after CASA came= =20 the heavy, Aviation Consumer magazine in the US conducted some flight tests= on=20 the Lancair, and another fast plastic of similar size and shape, and=20 concluded their findings with some not very flattering remarks along the li= nes of=20 ......... how dare you foist on the unsuspecting public expensive machines=20 with such bad design features........ - I was very pleased to hear this as=20= it=20 vindicated the position taken by CASA and other professional Test Pilots wh= o=20 had flown the machines. =20 Very quickly the manufacturer of kit X came out with a bigger tail (about=20 50% bigger!), and some advice on how to fix the CG problem. Lancair eventu= ally=20 did the same=E2=80=A6=E2=80=A6=E2=80=9D=20 CASA is the current name for the old CAA here up over. Under a Labour=20 Government, the name changes every few weeks to create jobs. Although the q= uote=20 uses the current term CASA, at the time of testing the authority was called= CAA.=20 Hopefully this will help, if not cause the usual broad-ranging hackles=20 raising.=20 Cheers,=20 Dom Crain=20 VH-CZJ=20 Melbourne=20 Not Florida **************Start the year off right. Easy ways to stay in shape. =20 http://body.aol.com/fitness/winter-exercise?NCID=3Daolcmp00300000002489 -------------------------------1200247467 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en
Dom,
 
My hackles are in shackles.
 
I am not a test pilot (Hmmmmm, not trained anyway), but I stayed in a=20 Holiday Inn once.  While the OZ analysis is true, there are ways to=20 ameliorate the unfriendly small tail characteristics.  Here are some=20 thoughts gained over 850 hours behind the stick of a 320 and generally withi= n a=20 100 feet of a purposely hand held altitude in reasonably smooth air.&nb= sp;=20
 
1. Neutral to negative longitudinal stability confirmed. =20 Recognize it, understand it, deal with it (one way is with a larger tail, th= ere=20 are others).
2. Every Lancair 200/300 series is uniquely customized and details of=20 handling may differ while general characteristics could and should be=20 understood.
3. Instrument approaches in smooth air are a moderate challenge and whi= lst=20 in turbulent air, they are more interesting. (I believe that is a=20 quote from the Marquis de Sade shortly after he went flying in his 360.)
 
OK, here is a limited description of my components, customiza= tion=20 and their consequences.
a. Slow built 320, 1200 # empty weight and empty CG a hair forward= of=20 specs.
b. Properly installed bob-weight with the elevator bell crank= arm=20 reduced to 3" (stick throw reduced by 25%, forces increased from none to som= e).=20 60 degree banked (2G) full circle steep turns to the left with cruise t= rim=20 untouched require far more than 7 lbs of pull to hold altitude (no opposite=20 rudder) and the need for the pull is quite delayed after first entering= the=20 turn.  Right turns require less force and and the need to=20 apply the full holding force is delayed further than those steep=20 turns to the left.  Holding the altitude within 50 feet throughout= the=20 360 turn is a real challenge.  720 degree turns are easier because= by=20 then you've got it - until you hit your self induced burble. =20 Drat.
c. I have the Reichel geared trim wheel with stronger springs to=20 compensate for the shorter arm.  In cruise, spring controlled trim= =20 characteristics add to the sensitivity in pitch because of the broad=20= dead=20 band of little spring force exerted at the trimmed position, thus the=20 non-holding spring is relaxed and, if the plane is "balanced," even the= =20 hold spring is not pushing very hard.  In slow flight with flaps at som= e=20 extension, the holding spring is under greater tension and the sensitivity i= s=20 somewhat reduced.  I cannot compare my flight=20 characteristics to Lancairs equipped with tabbed-elevator tri= m=20 systems.
d. My horizontal tail surfaces are thinner than the plans cal= l=20 for.  Don't ask.  I don't know if there is a flight effect from th= at,=20 but it is different than the design.  I also have gap seals with unknow= n=20 effect on elevator/pitch controlability.
e. More forward CG results in a more stabilized pitch control.  Th= e=20 rear quarter of the CG range results in much less stability t= han=20 the front half.  Be aware of this when loading the plane.  Lancair= =20 moved the CG forward 1.5 inches without a detrimental effect (3" longer engi= ne=20 mount to compensate for added weight from the larger tail that=20 moved the CG aftward).  So, keep the CG more forward for better=20 flights.
 
Observed behavior and/or techniques to compensate:
i. Some have experienced an extreme nose bobbing when slipping at slow=20= air=20 speeds.  Try as I might, I could only induce gentle sinusoidal=20 bobbing, different from left or right (I don't remember which was=20 more).  Since I fly differently than others (Don't we all?), I have lit= tle=20 use for slip attitudes until just above the runway.  If not on an=20 instrument approach, slow down early, fly a higher pattern, fly a steep= er=20 final descent angle, carefully control the speed (AOA has helped).
ii. With respect to slow flight when nearing the airfield - in my=20 airplane, throttle back and slow to 160 KIAS early, tick the flaps out of re= flex=20 (resulting in rapid loss of airspeed and lowering the nose) and re-trim.&nbs= p; A=20 stabilized slow speed approach(110 to 120 KIAS) at low power with flaps= at=20 the takeoff position and everything trimmed is the most=20 stabilized, comfortable and with the least workload.  Final a= t=20 85-90 Kts.
iii. The lack of longitudinal stability is a bummer during an=20 approach:  Change of speed <=3D> change of attitude <=3D> c= hange of=20 descent rate.  Note the double pointed arrows.  Instrument approac= h=20 workload is increased when trying to manage these.  Turbulence doe= s=20 not assist the pilot. 
iv. Gap seals have provided a benefit such=20 that the rudder came alive at a lower airspeed (maybe 5 to 10=20 Kts).  I cannot say I noticed a difference with respect to the=20 elevator.  Gap seals are high maintenance items unless they are=20 built-in during construction.
v. I cannot get my Lancair to enter a turn by applying strong rudder in= puts=20 (Hmmmm, maybe I only tested this at cruise speeds).  In other words, I=20= do=20 not feel much, if any, roll tendencies from applying the rudder in leve= l=20 flight at cruise speeds.  I don't remember if I had to compensate=20 for roll in the bobbing tests.  The feel is different from left to= =20 right rudder.
 
The conclusion for me:  Yes, in certain flight regimes where stabi= lity=20 is desirable, it would be nice to have that stability available by design.&n= bsp;=20 Understanding your steed's characteristics can be useful if you=20 remember to take those into account when flying.  There are many=20 experimental and aerobatic planes extant that are twitchy - deal with t= hem=20 for they are not as forgiving as those designed to be fool-proof.
 
Possible conclusions for others:  Man, this ain't no spam can.&nbs= p;=20 Experiences will vary.  Learn it. Love it.  Stay on your toes.=20 Use O2 as needed. Pay attention to Mother Nature.  Occasional= ly=20 look out the window.  Don't do noth'n stoopid!
 
Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL (KARR)

Pil= ot=20 not TSO'd, Certificated score only > 70%.
 
PS:  Is it possible the CG range was originally computed from= the=20 un-reflexed wing characteristics?  That is, computed from the "nor= mal"=20 wing shape and thus set too far aft?
 
 
In a message dated 1/13/2008 7:31:02 A.M. Central Standard Time,=20 domcrain@tpg.com.au writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>

= The recent comments re= garding=20 the Small v. Big tail draw my attention to the fact that on a recent visit= to=20 the wide brown land up over, LML lister Angier was privileged to see two=20 examples of large tail Lancair's. One belonging to me (didn=E2=80=99t build it), a= nd the other=20 being the example quoted in the attached letter to Rob Wolf=E2=80=99s post= =E2=80=9CA look at=20 Lancair 360 Handling Qualities=E2=80=9D. Now owned by anoth= er lister=20 here.

= The only Lancair=E2=80=99s I have ha= ndled in the air=20 were all large tail versions, with one exception, that being N5ZQ in the=20 States. Bill will undoubtedly recall that I was =E2=80=93 let=E2=80=99s sa= y =E2=80=9Cropey=E2=80=9D =E2=80=93 to say=20 the least. While I am prepared to accept that is my lack of skill, and I=20 reflect long and hard on this after each flight I have made over forty odd= =20 years, I do come to the conclusion that there is a distinct improvement in= =20 stability and handling of the Lancair with the large tail.

= Over the past few mont= hs=20 =E2=80=93almost a year actually, there has been a slow but steady approach= to the=20 improvement of training of, and understanding by, Lancair pilots here up over= , brought=20 on by the historical global accident rate, and highlighted by two fatals=20 within six days in Australia, 20 months ago.

= A Lancair Pilot Group has bee= n=20 established, and having been asked to be involved, I have sought advice fr= om=20 various sources regarding their views on the matter of Lancair training and opinio= ns on=20 handling.

= In this process I have= had=20 email discussions with the test pilot who undertook some of the test flyin= g on=20 the Lancair which resulted in the recommendation to enlarge the= =20 tail.

= I quote from the email= I=20 received from one him on 20 September 2007:

=E2=80= =9C=E2=80=A6=E2=80=A6.When the=20 first example (a 320 I think?) was evaluated, it was found to have 2 major= =20 design problems/defects.  First the aft CG condition was unrealistic=20= (in=20 excess of 30% MAC), and the horizontal stabiliser was too small. =20 Combined these resulted in neutral or negative stick free longitudinal=20 stability.  Also manoeuvre stability (stick force per G) was at best=20 measured in ounces per G.  Standard comment from then owners was"I li= ke=20 it like that because it has fighter like feel."  These pilots had=20 obviously never flown a fighter, at least not one built since about 1920,=20 which all have positive long stab, and minimum stick forces of about 7=20 lb/G. 

CASA ins= isted=20 (under the good/bad old 101.28 rule) that stability be improved.  I t= hink=20 the aft CG limit was moved forward (not sure how much) and bigger tails we= re=20 required.  The bigger tails (2 local REG 35 solutions by Graham Swann= el=20 and Dave Simons) produced adequate solutions, but the practicalities of=20 keeping CG forward remained.  The Lancair 235/230= /360=20 models also have negative lateral sideslip stability; with a low wing= and=20 no dihedral the predominant rolling force in a sideslip is due to the=20 rudder.  This characteristic is rarely seen, and is disturbing when=20 deliberately sideslipping during cross wind approaches.  For IFR= =20 approval, CASA insisted this be fixed and a rudder/aileron interconnect wa= s=20 developed (I think by Dave Simons) which produced apparent lateral sidesli= p=20 stability and hence predictable handling qualities in=20 sideslip.

The kit=20 manufacturer was not amused by these criticisms of his creation and refuse= d to=20 have anything to do with them.  However, shortly after CASA came the=20 heavy, Aviation Consumer magazine in the US conducted some flight tests on= the=20 Lancair, and an= other=20 fast plastic of similar size and shape, and concluded their findings with=20= some=20 not very flattering remarks along the lines of ......... how dare you fois= t on=20 the unsuspecting public expensive machines with such bad design=20 features........ - I was very pleased to hear this as it vindicated the=20 position taken by CASA and other professional Test Pilots who had flown th= e=20 machines. 

Very qui= ckly=20 the manufacturer of kit X came out with a bigger tail (about 50% bigger!),= and=20 some advice on how to fix the CG problem.  Lancair eventua= lly=20 did the same=E2=80=A6=E2=80=A6=E2=80=9D

= CASA is the current na= me for=20 the old CAA here up over. Under a Labour Government, the name changes ever= y=20 few weeks to create jobs. Although the quote uses the current term CASA, a= t=20 the time of testing the authority was called CAA.

= Hopefully this will he= lp, if=20 not cause the usual broad-ranging hackles raising.

= Cheers,<= /P>

= Dom Crain

= VH-CZJ

= Melbourne

= Not Florida

<= /DIV>


Start the year off right.=20= Easy ways to stay in shape in the new y= ear.
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