X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 16 Oct 2009 15:57:07 -0400 Message-ID: X-Original-Return-Path: Received: from imr-ma03.mx.aol.com ([64.12.206.41] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3886748 for lml@lancaironline.net; Thu, 15 Oct 2009 10:51:58 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.206.41; envelope-from=Sky2high@aol.com Received: from imo-da03.mx.aol.com (imo-da03.mx.aol.com [205.188.169.201]) by imr-ma03.mx.aol.com (8.14.1/8.14.1) with ESMTP id n9FEou8g011410 for ; Thu, 15 Oct 2009 10:50:56 -0400 Received: from Sky2high@aol.com by imo-da03.mx.aol.com (mail_out_v42.5.) id q.ca7.50410be2 (29679) for ; Thu, 15 Oct 2009 10:50:53 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Thu, 15 Oct 2009 10:50:53 EDT Subject: Re: [LML] Re: FAA RESCINDS INFO LETTER X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1255618253" X-Mailer: AOL 9.1 sub 5006 X-Spam-Flag:NO X-AOL-SENDER: Sky2high@aol.com -------------------------------1255618253 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en Capt Tuna, =20 Yes, yes, yes. =20 BTW, the 300 series Lancairs have 70 sq ft of wing area and at 1600 lbs= =20 (well within the max gross wt), the wing loading is about 23 lbs/sqft. = In=20 other words, IV's shouldn't follow 320/360's and the 3xx's shouldn't foll= ow=20 RV's on close in patterns. =20 However, the accidents occurring close to an airport and low to the groun= d=20 have often occurred without other traffic being present. They also occur= =20 during both takeoff and landing phases (uh, also during low passes over = =20 somebody's house and off airport forced landings, etc). Your 3 points are= well=20 stated. I like the continuous U-turn from downwind to final, much like= =20 that used out of a low approach because the turn can be adjusted through= out=20 the maneuver - this eliminates ugly tightening in the middle of the =20 standard 90 degree segment from base to final. =20 Another technique for landing is to use a slightly higher pattern altitud= e=20 and a steeper final approach to provide more options using available=20 kinetic energy for uh, last minute adjustments. One must choose the righ= t time=20 to stop the descent and the energy dissipates quickly, but over the runwa= y.=20 =20 =20 In a Lancair, when something goes wrong, it goes wrong very fast. =20 Grayhawk Got gray by not always operating at the edge of the envelope. =20 =20 In a message dated 10/15/2009 7:59:22 A.M. Central Daylight Time, =20 frederickmoreno@bigpond.com writes: =20 Our hangar group which includes retired airline pilots, an Applied Physic= s=20 PhD and a couple of engineering guys has kicked this issue of pattern=20 stalls around over the last few weeks. From that discussion I posit a th= eory=20 for why Lancair guys are getting killed in the pattern. Conclusion: it= =20 takes more than a bad stall characteristic to get you killed. (You alre= ady=20 knew that.)=20 Fact: our resident RV-6 owner/pilot reports that the early RV=E2=80=99s= (before=20 RV-7) had a wing design that resulted in a sudden stall with big wing dro= p. =20 Sound familiar? The RV-7 which replaced the RV-6 has a completely=20 different wing profile to address this issue. However, RV-6s are not fal= ling out =20 of the sky and killing people in the pattern. =20 Fact: RV-6 wing loading is 1600 pounds on 110 square feet or 14.5 pounds= =20 per square foot. A Lancair IV (short wing) loading is more like 3200 pou= nds=20 on 98 square feet or about 33 pounds per square foot. When you fly an RV= 6=20 in the pattern at normal pattern speeds (75-80 knots, flaps out) and pull= =20 back on the stick turning final, it flies up. When you fly a Lancair IV= =20 around the corner at 120 knots and pull up, it slows down =E2=80=93 fairl= y rapidly =E2=80=93=20 because of the big change in angle of attack arising from high wing=20 loading (lots of momentum acting against a small wing panel). =20 Fact: Flying at 120 knots in the pattern, the Lancair IV will have a turn= =20 radius that is 2.25 times larger (1.5 squared) greater than the RV flyin= g=20 at 80 knots (same angle of bank). =20 Now let=E2=80=99s combine all these facts and propose an accident scenari= o. The=20 Lancair pilot enters downwind well behind slower traffic that is flying= a=20 pattern in close to the runway. Mistake one: he is too close to the runw= ay. =20 It is a busy day, lots of chatter, and he slows to his customary 120=20 knots, gear and flaps out. =20 He then turns base, but his turn radius is 2.25 times larger than the RV= =20 he was following for the same angle of bank. As he rolls out on base, he= =20 can see that he will overshoot the runway centreline. Still lots of radi= o=20 chatter and he is watching the RV touchdown and roll out on the runway to= =20 make sure he has room. =20 Having crossed the runway centreline and while watching the RV and listen= =20 to the chatter, he banks a little more steeply than normal on his turn= to=20 final and pulls back, but he has not seen his airspeed indicator for mayb= e=20 15 seconds. A bit low to begin with, airspeed starts to decay rapidly.= He=20 gets most of the way around the turn, the airspeed continues to decay= at=20 an accelerating rate, he gives the stick a little more of a tug to tighte= n=20 the turn since he is now well past the centreline, and the airplane stall= s=20 out of a 30-45 degree bank at 500 feet. End of pilot and airplane. =20 Accidents arise from a series of events. The events here were: =20 1) Downwind leg in too close following the =E2=80=9Cnormal=E2=80=9D= traffic. =20 Solution: fly a very wide downwind regardless of where the slow guys are= flying. =20 2) Decay of airspeed not noted after first turn or during second turn= .=20 Solution: Eagle eye on the air speed indicator all the time,=20 particularly when making the turn downwind to base and then base to final= . Limit to=20 15 degree bank. =20 3) Pulled back on the stick after passing the runway centreline to=20 tighten the turn while at too low a speed. Solution: Never pull back on= the=20 stick or roll in more bank angle to tighten the turn when in the pattern.= =20 Stick with the 15 degree bank limit in the pattern. =20 I still find myself flying my downwind too close to the runway when=20 following traffic. It is force of a very old habit that must be broken.= But =20 when I fly a big pattern and make a large U-turn from downwind to final= with=20 no more than 15 degree bank, the margins at 120 knots remain large and= it=20 all works out much more nicely with sped control being much easier. =20 The RV 6 stall can be nasty, but it is not the nasty stall that kills=20 Lancair IV pilots. My theory: pattern in too close, air speed not watche= d,=20 turn to final pulled too tight because of the pattern air speed was allow= ed to=20 decay and pattern being too tight to begin with. Stall spin crash burn.= =20 =20 The yellow alarm lights should go on when you are in close to the runway,= =20 or when the cross wind blows you toward the runway on downwind. Be=20 careful. =20 Your comments welcome. =20 Captain Tuna, Chicken of the Skies=20 -------------------------------1255618253 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en
Capt Tuna,
 
Yes, yes, yes.
 
BTW, the 300 series Lancairs have 70 sq ft of wing area and at= 1600=20 lbs (well within the max gross wt), the wing loading is about 23 lbs/sqft.=  =20 In other words, IV's shouldn't follow 320/360's and the 3xx's shouldn= 't=20 follow RV's on close in patterns.
 
However, the accidents occurring close to an airport and low to= the=20 ground have often occurred without other traffic being present. They also= occur=20 during both takeoff and landing phases (uh, also during low passes over=20 somebody's house and off airport forced landings, etc).  Your 3 point= s are=20 well stated.  I like the continuous U-turn from downwind to final, mu= ch=20 like that used out of a low approach because the turn can be adjusted thro= ugh=20 out the maneuver - this eliminates ugly tightening in the middle of t= he=20 standard 90 degree segment from base to final.
 
Another technique for landing is to use a slightly higher patter= n=20 altitude and a steeper final approach to provide more options using= =20 available kinetic energy for uh, last minute adjustments.  One= must=20 choose the right time to stop the descent and the energy dissipates quickl= y, but=20 over the runway.  
 
In a Lancair, when something goes wrong, it goes wrong very fast.
 
Grayhawk
Got gray by not always operating at the edge of the envelope.
 
In a message dated 10/15/2009 7:59:22 A.M. Central Daylight Time,=20 frederickmoreno@bigpond.com writes:

Our hangar= group=20 which includes retired airline pilots, an Applied Physics PhD and a coup= le of=20 engineering guys has kicked this issue of pattern stalls around over the= last=20 few weeks.  From that discussion I posit a theory for why Lancair= guys=20 are getting killed in the pattern.  Conclusion: it takes more than= a bad=20 stall characteristic to get you killed.   (You already knew=20 that.)

 = Fact: our= resident=20 RV-6 owner/pilot reports that the early RV=E2=80=99s (before RV-7) had= a wing design=20 that resulted in a sudden stall with big wing drop.  Sound=20 familiar?  The RV-7 which replaced the RV-6 has a completely differ= ent=20 wing profile to address this issue.  However, RV-6s are not falling= out=20 of the sky and killing people in the pattern.

 = Fact: RV-6= wing=20 loading is 1600 pounds on 110 square feet or 14.5 pounds per square=20 foot.  A Lancair IV (short wing) loading is more like 3200 pounds= on 98=20 square feet or about 33 pounds per square foot.  When you fly an RV= 6 in=20 the pattern at normal pattern speeds (75-80 knots, flaps out) and pull= back on=20 the stick turning final, it flies up.  When you fly a Lancair IV ar= ound=20 the corner at 120 knots and pull up, it slows down =E2=80=93 fairly rapi= dly =E2=80=93 because=20 of the big change in angle of attack arising from high wing loading (lot= s of=20 momentum acting against a small wing panel).

 = Fact: Flyin= g at 120=20 knots in the pattern, the Lancair IV will have a turn radius that is 2.2= 5=20 times larger  (1.5 squared) greater than the RV flying at 80 knots= (same=20 angle of bank). 

 = Now let=E2= =80=99s combine=20 all these facts and propose an accident scenario.  The Lancair pilo= t=20 enters downwind well behind slower traffic that is flying a pattern in= close=20 to the runway.  Mistake one: he is too close to the runway. = It is a=20 busy day, lots of chatter, and he slows to his customary 120 knots, gear= and=20 flaps out.

 = He then tur= ns base,=20 but his turn radius is 2.25 times larger than the RV he was following fo= r the=20 same angle of bank.  As he rolls out on base, he can see that he wi= ll=20 overshoot the runway centreline.  Still lots of radio chatter and= he is=20 watching the RV touchdown and roll out on the runway to make sure he has= room.=20

 = Having cros= sed the=20 runway centreline and while watching the RV and listen to the chatter,= he=20 banks a little more steeply than  normal on his turn to final and= pulls=20 back, but he has not seen his airspeed indicator for maybe 15 seconds.&n= bsp; A=20 bit low to begin with, airspeed starts to decay rapidly.  He gets= most of=20 the way  around the turn,  the airspeed continues to decay at= an=20 accelerating rate, he gives the stick a little more of a tug to tighten= the=20 turn since he is now well past the centreline, and the airplane stalls= out of=20 a 30-45 degree bank at 500 feet.   End of pilot and airplane.= =20

 = Accidents= arise=20 from a series of events.  The events here were: <= /P>

1)   =20 Downwind le= g in too=20 close following the =E2=80=9Cnormal=E2=80=9D traffic.  Solution: fl= y a very wide downwind=20 regardless of where the slow guys are flying.

2)   =20 Decay of ai= rspeed=20 not noted after first turn or during second turn.   Solution:= Eagle=20 eye on the air speed indicator all the time, particularly when making th= e turn=20 downwind to base and then base to final.  Limit to 15 degree bank.= =20

3)   =20 Pulled back= on the=20 stick after passing the runway centreline to tighten the turn while at= too low=20 a speed.  Solution: Never pull back on the stick or roll in more ba= nk=20 angle to tighten the turn when in the pattern.  Stick with the 15= degree=20 bank limit in the pattern. 

 = I still fin= d myself=20 flying my downwind too close to the runway when following traffic. = It is=20 force of a very old habit that must be broken.  But  when I fl= y a=20 big pattern and make a large U-turn from downwind to final with no more= than=20 15  degree bank, the margins at 120 knots remain large and it all= works=20 out much more nicely with sped control being much easier.=20

 = The RV 6 st= all can=20 be nasty, but it is not the nasty stall that kills Lancair IV pilots.&nb= sp; My=20 theory: pattern in too close, air speed not watched, turn to final pulle= d too=20 tight because of the pattern air speed was allowed to decay and pattern= being=20 too tight to begin with.  Stall spin crash burn. =20

 = The yellow= alarm=20 lights should go on when you are in close to the runway, or when the cro= ss=20 wind blows you toward the runway on downwind.  Be careful.=20

 = Your commen= ts=20 welcome.

 = Captain Tun= a,=20 Chicken of the Skies

 =

 =

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