X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 22 Jan 2010 10:35:15 -0500 Message-ID: X-Original-Return-Path: Received: from mail-ew0-f212.google.com ([209.85.219.212] verified) by logan.com (CommuniGate Pro SMTP 5.3.1) with ESMTP id 4091293 for lml@lancaironline.net; Thu, 21 Jan 2010 20:25:18 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.219.212; envelope-from=jeffreyb.peterson@gmail.com Received: by ewy4 with SMTP id 4so774999ewy.7 for ; Thu, 21 Jan 2010 17:24:43 -0800 (PST) DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:reply-to:date:message-id:subject:from:to:content-type; b=gZ9F4ULqbmFd5I/i6cZyrUjgUcKU6FWnaFKni+A1RLDEVUmMHglsGfWmwPxMQKosYc LdJyek9nWH/BbEz4HNxXC+3jC0J7HY5CKakzUMHmib91T0va9mkf4/M5hNaOR6G6+ukT xBKuhHFuUIMaislViyua46zh/lsa26++HMmj8= MIME-Version: 1.0 Received: by 10.216.87.66 with SMTP id x44mr866868wee.96.1264123481680; Thu, 21 Jan 2010 17:24:41 -0800 (PST) Reply-To: jbp@cmu.edu X-Original-Date: Thu, 21 Jan 2010 20:24:41 -0500 X-Original-Message-ID: <7b85bf8e1001211724h14dbe167qaf1c6363da77404b@mail.gmail.com> Subject: Re: Do-it-yourself AOA Project From: Jeff Peterson X-Original-To: Lancair mail list Content-Type: multipart/alternative; boundary=0016e6d99c2c13ef3d047db6afd6 --0016e6d99c2c13ef3d047db6afd6 Content-Type: text/plain; charset=ISO-8859-1 LML: I have been tinkering with an AOA circuit. I posted the schematic here: http://w1.lancair.net/pix/Angle-of-Attack-Circuit The circuit has a few improvements over previous ones. It uses bar graph mode with an all-green LED display. As you raise the angle the green (good) bars disappear. A glance tells you how much reserve (green) you have. When the last green goes out the vy bright red lights come on and the horn sounds. This is the stall warning, (actually per-stall). My thought is to use an angle-adjustable probe like that used by alpha systems, and set the angle with the plane configured for landing...flaps down. Then, on climb out, with less flaps, the stall warning triggers a bit early, I think. That seems OK to me. On landing one is intentionally bleeding off speed and and a precise lift reserve indication is what you want. On climbout, in our overpowered lanciars, one would rarely want to be anywhere close to stall. So, for me, the KIS principle wins the day and I think an offset based on flaps in not needed. -- Jeff Peterson Dept of Physics, CMU --0016e6d99c2c13ef3d047db6afd6 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable LML:

I have been tinkering with an AOA circuit. I posted the schemat= ic here:

http://w1.lancair.net/pix/Angle-of-Attack-Circuit

The circuit= has a few improvements over previous ones.
It uses bar graph mode with an all-green LED display.
As you raise the a= ngle the green (good) bars disappear.
A glance tells you how much reserv= e (green) you have.

When the last green goes out the vy bright red l= ights=A0 come on and the horn sounds.
This is the stall warning, (actually per-stall).

My thought is to us= e an angle-adjustable probe like that used by alpha systems, and set the an= gle
with the plane configured for landing...flaps down.

Then, on = climb out, with less flaps, the stall warning triggers a bit early, I think= . That seems OK to me.
On landing one is intentionally bleeding off speed and and a precise lift r= eserve indication is what you want.
On climbout, in our overpowered lanc= iars, one would rarely want to be anywhere close to stall.

So, for m= e, the KIS principle wins=A0 the day and I think an offset based on flaps i= n not needed.

--
Jeff Peterson
Dept of Physics, CMU
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