Return-Path: Sender: "Marvin Kaye" To: lml@lancaironline.net Date: Sat, 25 Sep 2004 01:27:14 -0400 Message-ID: X-Original-Return-Path: Received: from hagus.bright.net ([209.143.0.74] verified) by logan.com (CommuniGate Pro SMTP 4.2.3) with ESMTP id 431482 for lml@lancaironline.net; Fri, 24 Sep 2004 20:45:03 -0400 Received-SPF: none receiver=logan.com; client-ip=209.143.0.74; envelope-from=airmale@bright.net Received: from bright.net (paul-bryn-breeze-122.wireless.bright.net [216.201.20.123] (may be forged)) by hagus.bright.net (8.12.10/8.12.10) with ESMTP id i8P0iD5N025389; Fri, 24 Sep 2004 20:44:31 -0400 (EDT) X-Original-Message-ID: <4154BF60.4010606@bright.net> X-Original-Date: Fri, 24 Sep 2004 20:44:16 -0400 From: J H Webb User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 (ax) X-Accept-Language: en-us, en MIME-Version: 1.0 X-Original-To: "Bill Kennedy" , Lancair Mailing List Subject: 320/360 stalls. Content-Type: multipart/alternative; boundary="------------010608050007040905070302" This is a multi-part message in MIME format. --------------010608050007040905070302 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Posted for "Bill Kennedy" : > I'm jealous -- my 320 is not so nearly well behaved. I usually get an abrupt >drop of the left wing, but recover easily. Wonder what I could tweak to make >it act more docile? Being a former Engineering test pilot for a major manufacturer and having done thousands (no exaggeration) of stalls to improve and to determine stall characteristics. It will take a little time, but the stalls can be improved without any loss of top speed. There two ways to improve a stall like that one is to revise the angle of incidence of the wing. This is a little hard on a 320/360. The other way to improve the stall is to experiment with flow strips (stall strips). First you determine your stall speed. The goal is to improve the stall without significantly changing the stall speed. Usually the stall handing qualities can be significantly improved by flow strips. So we will try to improve the stall handing while noting the change in stall speed. I would start with 3 or 4 inch long strips,1/4" right angle aluminum works nicely as you can tape this on to your wing leading edge slightly below the stagnation point just inboard of the wing attach gap to the stub wing. Then fly and check on the handling qualities and note the stall speed. If it rolls to the right and there is no or little change in the stall speed move the left strip up about 1/8" and refly noting the stall speed. The idea in this change is to increase the stall speed of the left wing to more closely match the right wing. If after this procedure we get a good handling stall but if the stall speed is up over 5 mph we need to move the flow strips down on both wings about 1/16 to 1/8" This will reduce the speed that the stall initiates. There are a multitude of variables but having designed several flow strip installations to improve handling, this is good view of the basics. You need to write down each test configuration as later you might find that a previous configuration is better. Be sure to carefully mark the location of the strips as a little change can be very significant. If you have questions don't hesitate to call or write. Jack Webb L 360, L IV ATP, CFI Airplanes & Instruments, Multi, & Sea Many Type Ratings Experienced Experimental Test Pilot both multi and single engine Former Chief Engineering Test Pilot for a Major Manufacturer AeroSpace Engineer BSAE Ohio 419 399 5500 --------------010608050007040905070302 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit Posted for "Bill Kennedy" <bill_kennedy_3@hotmail.com>:

> I'm jealous -- my 320 is not so nearly well behaved. I usually get an abrupt
>drop of the left wing, but recover easily. Wonder what I could tweak to make
>it act more docile?

Being a former Engineering test pilot for a major manufacturer and having done thousands (no exaggeration) of stalls to improve and to determine stall characteristics.  It will take a little time, but the stalls can be improved without any loss of top speed.  There two ways to improve a stall like that one is to revise the angle of incidence of the wing.  This is a little hard on a 320/360.  The other way to improve the stall is to experiment with flow strips (stall strips).  First you determine your stall speed.  The goal is to improve the stall without significantly changing the stall speed. Usually the  stall handing qualities can be significantly improved by flow strips.  So we will try to improve the stall handing while noting the change in stall speed. 
    I would start with 3 or 4 inch long strips,1/4" right angle aluminum  works nicely as you can tape this on to your wing leading edge slightly below the stagnation point just inboard of the wing attach gap to the stub wing.  Then fly and check on the handling qualities and note the stall speed. If it rolls to the right and there is no or little change in the stall speed move the left strip up about 1/8" and refly noting the stall speed. The idea in this change is to increase the stall speed of the left wing to more closely match the right wing. 
    If after this procedure we get a good handling stall but if the stall speed is up over 5 mph we need to move the flow strips down on both wings about 1/16 to 1/8"  This will reduce the speed that the stall initiates.  There are a multitude of variables but having designed several flow strip installations to improve handling, this is good view of the basics.
    You need to write down each test configuration as later you might find that a previous configuration is better.  Be sure to carefully mark the location of the strips as a little change can be very significant. If you have questions don't hesitate to call or write.

Jack Webb
L 360, L IV
ATP, CFI Airplanes & Instruments, Multi, & Sea
Many Type Ratings
Experienced Experimental Test Pilot both multi and single engine
Former Chief Engineering Test Pilot for a Major Manufacturer
AeroSpace Engineer BSAE
Ohio
419 399 5500


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