X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 22 Jun 2008 21:51:17 -0400 Message-ID: X-Original-Return-Path: Received: from europa.lunarpages.com ([209.200.229.75] verified) by logan.com (CommuniGate Pro SMTP 5.2.3) with ESMTPS id 2979366 for lml@lancaironline.net; Sun, 22 Jun 2008 11:42:01 -0400 Received-SPF: none receiver=logan.com; client-ip=209.200.229.75; envelope-from=aflyer@lazy8.net Received: from ip-206-123-213-175.static.fasttrackcomm.net ([206.123.213.175] helo=blueroom) by europa.lunarpages.com with esmtp (Exim 4.68) (envelope-from ) id 1KARgU-0008Sb-EP for lml@lancaironline.net; Sun, 22 Jun 2008 08:40:54 -0700 From: "John Huft" X-Original-To: "'Lancair Mailing List'" References: In-Reply-To: Subject: RE: [LML] IAS Error/ Trouble shooting tips? X-Original-Date: Sun, 22 Jun 2008 09:38:53 -0600 X-Original-Message-ID: <064f01c8d47e$1e85eb80$5b91c280$@net> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0650_01C8D44B.D3EB7B80" X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: AcjUdbmWR4XrcPWsRvGSFMCRzmxJCQAB39jg Content-Language: en-us X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - europa.lunarpages.com X-AntiAbuse: Original Domain - lancaironline.net X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - lazy8.net This is a multipart message in MIME format. ------=_NextPart_000_0650_01C8D44B.D3EB7B80 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Larry, the RV guys have been through this a few times. One of the tool suppliers sold a "flush" static port kit. It looked real nice, but lead to errors like your friend's. You didn't mention if your altimeters were also disagreeing. It seems the pressure in the boundary layer is not the same as free stream pressure. But, if the port sticks out a little, it works. One popular fix is to just take the head of a pop rivet (with the hole in the center) and glue it over the flush port. Another is to replace the port with one that sits 1/8" or so proud of the surface. STEC sells one like that, and also a little spoiler that goes upstream of the port. This is all airframe specific of course, so YMMV. I know that no self respecting Lancair guy would just use an entire pop-rivet like Van's suggests in their plans (neither would I). John Huft RV spy From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Larry Henney Sent: Sunday, June 22, 2008 8:38 AM To: lml@lancaironline.net Subject: [LML] IAS Error/ Trouble shooting tips? Gents, I flew formation with a 320 today that had an IAS 20 kts above mine in welded wing. The weird part was that the a/c had an IFR pitot/static transponder cert less than a month ago. Additionally, the internal static port was found to be loose and the shop reattached it and certified the installation. Meanwhile the airspeed indicator was sent out for check out and was yellow tagged with no problem found. What is wrong with my buddies airspeed system? Inquiring minds need to know. TIA for helping us mitigate trouble shooting. Larry Henney N360LH IAS within a couple kts of a dozen other planes. ------=_NextPart_000_0650_01C8D44B.D3EB7B80 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Larry, the RV guys have been through this a few times. = One of the tool suppliers sold a “flush” static port kit. It looked = real nice, but lead to errors like your friend’s. You didn’t = mention if your altimeters were also disagreeing.

It seems the pressure in the boundary layer is not the = same as free stream pressure. But, if the port sticks out a little, it = works.

One popular fix is to just take the head of a pop rivet = (with the hole in the center) and glue it over the flush port. Another is to = replace the port with one that sits 1/8” or so proud of the surface. STEC = sells one like that, and also a little spoiler that goes upstream of the = port.

This is all airframe specific of course, so YMMV. I know = that no self respecting Lancair guy would just use an entire pop-rivet like = Van’s suggests in their plans (neither would I).

John Huft

RV spy

From:= Lancair = Mailing List [mailto:lml@lancaironline.net] On Behalf Of Larry Henney
Sent: Sunday, June 22, 2008 8:38 AM
To: lml@lancaironline.net
Subject: [LML] IAS Error/ Trouble shooting = tips?

Gents,=

I flew formation with a 320 today that had an IAS 20 kts above mine in = welded wing. The weird part was that the a/c had an IFR pitot/static = transponder cert less than a month ago. Additionally, the internal static port = was found to be loose and the shop reattached it and certified the installation. Meanwhile the airspeed indicator was sent out for = check out and was yellow tagged with no problem found.

What is wrong with my buddies airspeed system? Inquiring minds need to = know.

TIA for helping us mitigate trouble shooting.

Larry Henney

N360LH=

IAS within a couple kts of a dozen other planes.

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