X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 2 [X] Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 28 Feb 2007 00:23:56 -0500 Message-ID: X-Original-Return-Path: Received: from imo-m16.mx.aol.com ([64.12.138.206] verified) by logan.com (CommuniGate Pro SMTP 5.1.7) with ESMTP id 1872928 for lml@lancaironline.net; Tue, 27 Feb 2007 23:25:40 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.138.206; envelope-from=PTACKABURY@aol.com Received: from PTACKABURY@aol.com by imo-m16.mx.aol.com (mail_out_v38_r7.6.) id q.bbd.11966e50 (29678) for ; Tue, 27 Feb 2007 23:24:45 -0500 (EST) From: PTACKABURY@aol.com X-Original-Message-ID: X-Original-Date: Tue, 27 Feb 2007 23:24:45 EST Subject: Re: [LML] stall strip survey (IVP) X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1172636685" X-Mailer: 9.0 Security Edition for Windows sub 5354 X-Spam-Flag: NO -------------------------------1172636685 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit I too am just finishing my 40 hours of phase 1 on Lancair IV N94PT (no pressure, TSIO-550). I started with 10 inch long stall strips (triangles of plastic about 3/8 inch on a side taped to the leading edge) mounted 15 inches outboard of the wing/fuse joint. They were mounted at the leading edge stagnation point (as best as Charlie Kohler could eyeball it), eg at the tangent point of a vertical line with the plane level. I took some stall data in this config and then removed the strips and repeated. With the strips I had about 5 KIAS of warning and never actually experienced a developed stall as I initiated recovery at the buffet. Without the strips I experienced an abrupt right bank of about 45 to 60 degrees. Forward stick, a little aileron against the bank and the recovery was positive and immediate with a few hundred feet of altitude loss. There was no aerodynamic warning prior to the stall, at least none that was useful. Power was idle, ball centered, CG forward for all stall tests. I did both 1 G and accelerated stalls, clean and configured, light (~2600#) and moderate (~2850#) weight. The speeds varied some but the characteristics were consistent. First indication of buffet, 1 G: without strips, light: Vs: 73 KIAS, Vso: 68 KIAS without strips, moderate: Vs: 77 KIAS, Vso: 72 KIAS with strips, light: Vs: 78 KIAS, Vso: 70 KIAS I have set my Chelton warning (Vs) at 80 KIAS so it doesn't always come on at touch down but does provide a reasonable comfort zone prior to stall. I have not decided whether I am going to reinstall the strips prior to paint. regards, paul

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I too am just finishing my 40 hours of phase 1 on Lancair IV N94PT= (no=20 pressure, TSIO-550). I started with 10 inch long stall strips (triangl= es=20 of plastic about 3/8 inch on a side taped to the leading edge) mounted=20= 15=20 inches outboard of the wing/fuse joint. They were mounted at the leadi= ng=20 edge stagnation point (as best as Charlie Kohler could eyeball it), eg at th= e=20 tangent point of a vertical line with the plane level. I took some sta= ll=20 data in this config and then removed the strips and repeated. With the= =20 strips I had about 5 KIAS of warning and never actually experienced a develo= ped=20 stall as I initiated recovery at the buffet. Without the strips I=20 experienced an abrupt right bank of about 45 to 60 degrees. Forward st= ick,=20 a little aileron against the bank and the recovery was positive=20 and immediate with a few hundred feet of altitude loss. There was= no=20 aerodynamic warning prior to the stall, at least none that was useful. = =20 Power was idle, ball centered, CG forward for all stall tests. I = did=20 both 1 G and accelerated stalls, clean and configured, light (~2600#) and=20 moderate (~2850#) weight. The speeds varied some but the characteristi= cs=20 were consistent.

First indication of buffet, 1 G:

without strips, light:

Vs: 73 KIAS, Vso: 68 KIAS

without strips, moderate:

Vs: 77 KIAS, Vso: 72 KIAS

with strips, light:

Vs: 78 KIAS, Vso: 70 KIAS

I have set my Chelton warning (Vs) at 80 KIAS so it doesn't always come= on=20 at touch down but does provide a reasonable comfort zone prior to=20 stall. I have not decided whether I am going to reinstall the strips p= rior=20 to paint.

regards, paul

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