Return-Path: Sender: "Marvin Kaye" To: lml@lancaironline.net Date: Thu, 31 Mar 2005 20:15:53 -0500 Message-ID: X-Original-Return-Path: <5zq@cox.net> Received: from lakermmtao10.cox.net ([68.230.240.29] verified) by logan.com (CommuniGate Pro SMTP 4.3c3) with ESMTP id 850873 for lml@lancaironline.net; Thu, 31 Mar 2005 19:57:47 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.240.29; envelope-from=5zq@cox.net Received: from OFFICE ([68.110.249.147]) by lakermmtao10.cox.net (InterMail vM.6.01.04.00 201-2131-118-20041027) with SMTP id <20050401005656.FZMA29924.lakermmtao10.cox.net@OFFICE> for ; Thu, 31 Mar 2005 19:56:56 -0500 X-Original-Message-ID: <00fd01c53655$86c73750$6401a8c0@OFFICE> From: "Bill&Sue" <5zq@cox.net> X-Original-To: "Lancair Mailing List" References: Subject: Re: [LML] The Iceman cometh (down gently) X-Original-Date: Thu, 31 Mar 2005 19:55:40 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00FA_01C5362B.9DA00210" 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_00FA_01C5362B.9DA00210 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hello Scott, 1. Do you think that the freezing rain contained super-cooled = large droplets? I understand this to be the worst and almost impossible = to create in flight tests. I'm convinced that it was freezing rain. Just how large the droplets, = I can't say. Probably fairly large due to the splash pattern and the = extreme rapidity of accumulation. =20 2.. Do you think that Lancair=E2=80=99s being equipped with excess = power (more than minimally required in STC=E2=80=99d aircraft) = contributed to the successful outcome Well, I'm glad that I didn't have any LESS power, but the fact is; no = matter how much power, the airplane was going to reach the surface in = short order. I just abreviated the approach as much as possible to have = the runway under the plane when it got to the surface.=20 =20 3.. Could you report on the tail plane icing? I read the story of = the prolonged climb with the ice locking control surfaces on the IV = =E2=80=93 Ice buildup on the under surfaces, too? I have been concerned = about the tail because of the sharp leading edges and the potential for = building ice first. The horned pattern ("horns" above and below the LE with a forward = facing concave shape between them) was the same on the h stab as the = wing. I was aware of the possibility of freezing the controls and kept = moving them rapidly every 30 seconds or so. At no time did any of the = controls freeze. My elevator counter weight is "faired" behind the h = stab pretty well and, as far as I could tell accumulated no ice. One = feature of the LNC2 that probably helped is the fact that there is not = very much tail down force required to maintain level flight. This is one = of the things that makes our planes so sensitive in pitch. In an icing = situation, it probably helped prevent a tail plane stall. BTW I have the = small tail. =20 4. What did the plane feel like with the initial partial = extension of the flaps =E2=80=93 pitch=20 and controllability?=20 Controllability was good, although I didn't do a whole lot of = unnecessary maneuvering. I did bring the flaps out of reflex in order to = try to reduce AOA. I think that I got them to "0" before I accumulated = the worst of the ice. The airplane felt about like it would without ice = but with about 12" manifold pressure. Now for the poser. This only pertains to Lancair 235/320/360s and = their special wings with reflexed flaps=E2=80=A6=E2=80=A6=E2=80=A6.=20 =20 We know that these wings have certain characteristics with the flap at = zero degrees. The reflex position (-7 degrees) is utilized to reduce = lift and drag with a change in the center of lift causing a nose up = pitch (AOA change too). This is inherent in the design.=20 =20 So, when slowed down by carrying ice would it be better to return the = flaps to the zero degree position in order to lower the nose, reduce the = angle of attack and increase the lift? =20 Yes, I think that this is the best thing to do. One thing to remember, = every icing encounter is different. I'm sure that how the ice shapes = itself on the LE makes a large difference in handling and performance. = The forward facing concave shape that I encountered is unusual, I've = never seen anything like that before. Tail plane stall is a definite = possibility in most airplanes with a lot of ice. That was one of the = things I was most worried about and one of the reasons why I didn't = reduce airspeed below 120 kts until at the runway. Bill Harrelson 5zq@cox.net N5ZQ 320 950+ hrs N6ZQ IV 1% ------=_NextPart_000_00FA_01C5362B.9DA00210 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable =EF=BB=BF
Hello Scott,
 

    = 1.=20 Do = you think=20 that the freezing rain contained super-cooled large droplets?  I understand this to be the = worst and=20 almost impossible to create in flight tests.

I'm convinced=20 that it was freezing rain. Just how large the droplets, I can't say. = Probably=20 fairly large due to the splash pattern and the extreme rapidity of=20 accumulation.

 

  1. Do you think that = Lancair=E2=80=99s=20 being equipped with excess power (more than minimally required in = STC=E2=80=99d=20 aircraft) contributed to the successful outcome
Well, I'm glad=20 that I didn't have any LESS power, but the fact is; no matter how much = power,=20 the airplane was going to reach the surface in short order. I just = abreviated=20 the approach as much as possible to have the runway under the=20 plane when it got to the surface. 
 

 

  1. Could you report on = the tail=20 plane icing?  I read = the story=20 of the prolonged climb with the ice locking control surfaces on the = IV =E2=80=93 Ice=20 buildup on the under surfaces, too? =20 I have been concerned about the tail because of the sharp = leading=20 edges and the potential for building ice = first.

The=20 horned pattern ("horns" above and below the LE with a forward facing = concave=20 shape between them) was the same on the h stab as the wing. I was = aware=20 of the possibility of freezing the controls and kept moving them = rapidly every=20 30 seconds or so. At no time did any of the controls freeze. My = elevator=20 counter weight is "faired" behind the h stab pretty well = and, as far=20 as I could tell accumulated no ice. One feature of the LNC2 that = probably=20 helped is the fact that there is not very much tail down force = required to=20 maintain level flight. This is one of the things that makes our planes = so=20 sensitive in pitch. In an icing situation, it probably helped = prevent a=20 tail plane stall. BTW I have the small=20 tail.   

 

    =20 4.  What did the plane feel like with the initial partial = extension of=20 the flaps =E2=80=93 pitch
         =20 and controllability?

 Controllability was good, although I didn't do a whole = lot of=20 unnecessary maneuvering. I did bring the flaps out of reflex in order = to try=20 to reduce AOA. I think that I got them to "0" before I accumulated the = worst=20 of the ice. The airplane felt about like it would without ice but = with=20 about 12" manifold pressure.

 

 

Now for the poser.  This only pertains to = Lancair=20 235/320/360s and their special wings with reflexed = flaps=E2=80=A6=E2=80=A6=E2=80=A6.=20

 

We know that these wings = have=20 certain characteristics with the flap at zero degrees.  The reflex position (-7 = degrees) is=20 utilized to reduce lift and drag with a change in the center of lift = causing a=20 nose up pitch (AOA change too). =20 This is inherent in the design.

 

So, when slowed down by = carrying=20 ice would it be better to return the flaps to the zero degree position = in=20 order to lower the nose, reduce the angle of attack and increase the=20 lift? 

 

Yes, I think that = this is the=20 best thing to do. One thing to remember, every icing encounter is = different. I'm sure that how the ice shapes itself on the LE makes a = large=20 difference in handling and performance. The forward facing concave = shape that=20 I encountered is unusual, I've never seen anything like = that before. Tail=20 plane stall is a definite possibility in most airplanes with a lot of = ice.=20 That was one of the things I was most worried about and one of the=20 reasons why I didn't reduce airspeed below 120 kts until at the=20 runway.

 

 

Bill=20 Harrelson

5zq@cox.net

N5ZQ  320  = 950+=20 hrs

N6ZQ   = IV  =20 1%

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