X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 13 Jan 2010 13:13:13 -0500 Message-ID: X-Original-Return-Path: Received: from mta21.charter.net ([216.33.127.81] verified) by logan.com (CommuniGate Pro SMTP 5.3.1) with ESMTP id 4081269 for lml@lancaironline.net; Wed, 13 Jan 2010 12:28:06 -0500 Received-SPF: pass receiver=logan.com; client-ip=216.33.127.81; envelope-from=troneill@charter.net Received: from imp11 ([10.20.200.11]) by mta21.charter.net (InterMail vM.7.09.02.04 201-2219-117-106-20090629) with ESMTP id <20100113172730.UIQK21519.mta21.charter.net@imp11> for ; Wed, 13 Jan 2010 12:27:30 -0500 Received: from [192.168.1.100] ([75.132.241.174]) by imp11 with smtp.charter.net id V5TV1d00J3mUFT7055TV7B; Wed, 13 Jan 2010 12:27:30 -0500 X-Authority-Analysis: v=1.0 c=1 a=fLuM78UsAAAA:8 a=pGLkceISAAAA:8 a=g-bgjoMuAAAA:20 a=Ia-xEzejAAAA:8 a=HcG2t6x9msBy3NCYmt0A:9 a=T-S6VjuQxvTa6cc9BoYA:7 a=GROMONuNrwVOWVv-9ATSY1uPT5EA:4 a=6e4CQMaF2vYA:10 a=3jk_M6PjnjYA:10 a=MSl-tDqOz04A:10 a=dAFBrttHbWkRmE84PZUA:9 a=4d2vzchFkvhchFjIRuEA:7 a=UupFRH0gQAIgzoIeAWZ0Nclgm7wA:4 From: Terrence O'Neill Mime-Version: 1.0 (Apple Message framework v1077) Content-Type: multipart/alternative; boundary=Apple-Mail-13--518875653 Subject: Re: [LML] Re: angle of attack X-Original-Date: Wed, 13 Jan 2010 11:27:29 -0600 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: X-Mailer: Apple Mail (2.1077) --Apple-Mail-13--518875653 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Here's the DIY AOA I call the Bacon Saver, named by my late friend and = ex-P-39 pilot Marty Haedtler, an early EAA Director when Najeeb Halaby = was head of the FAA. in the early 1960s. I put on my Model W, on the = Jake and Magnum, on the Dragonfly, the Mitchell B-10/O'2, and now on our = Lancair 235/320. Anyone can make one, or I'll make one for you for $200. plus shipping. It uses a stainless shielded ball bearing with 1/8" bore, a = counterbalanced vane, and mounts 20% of the local wing chord ahead of = the leading edge, outside the propblast, and close enough to be in the = pilot's left field of vision. It is simple and self-contained, mechanical, no electrics. It's just a wind vane that tells you what the AOA of the wing is, no = matter what. I calibrate it by doing some stalls while watching where it is poijnting = at the break, and then mark the angle with automotive pinstriping = tape... mark a second mark AOA for best rate of climb, or whatever angle = you want. The actual angle in degrees is irrelevant. It was reassuring when I took off once and the pitot line pulled off. = Just flew the AOA. Also makes steep turns on final no-sweat. I can fly a few degrees below = stall AOA in any attitude, any airspeed, temp or turbulence. IMHO the AOA with lights are only accurate usually to about 3 or 4 = degrees and don't tell you how far above -- above -- stall you are, = where as the little Bacon Saver tells you exactly to what angle to pitch = the wing down to recover from a stall, for minimum altitude loss. Mine's mounted into a tube I bonded to the rib at the end of the wing = stub, removable with a taped-on 3/32 flush rivet through the tube. Any questions or suggestions are welcome. Make one yourslef, and get an = AOA on your plane, and take the sweat out of slow flight or high AOA = flight. Terrence L235/320 N211AL On Jan 12, 2010, at 6:44 PM, marv@lancair.net wrote: > Posted for Jeff Peterson : >=20 > If you are interested in homebuilt angle of attack systems > you might want to read this thread on rec.aviation.homebuilt > =20 > = http://groups.google.com/group/rec.aviation.homebuilt/browse_thread/thread= /bc8acb7472d0698e/dfc062e386e86a01?hl=3Den&lnk=3Dgst&q=3Dangle#dfc062e386e= 86a01 > =20 > I was surprise how many people are interested in the subject. > =20 > before building your own it pays to look at the > variety of commercially available system out there. > Two that use differential pressure systems are > =20 > Advanced Flight Systems and > Alpha Systems. > =20 > and several efis units now include some kind of AOA. > =20 > I have not flown with any of these but have collected a few opinions: > The audio beep output of the Alpha is very effective...gives = continuous > feedback during any high AOA operation, but with eyes outside. > The Alpha LED display looks cheap and clumsy (my opinion). > The AFS unit is cumbersome to set up in the cockpit and requires = probes > built in to the wing. > The AFS Pro display looks quite nice but is also pretty large. > =20 > =20 > =20 > I did breadboard my own design which has heartbeat audio feedback, > and a smaller display that either of either these units. I plan to = use the > Dynon heated Pitot/AOA probe. > My own work is not well enough along for me to > post schematics. I will post, if I get it working well. > =20 > Cheers, > =20 > --=20 > Jeff Peterson > LNC2 N273CK >=20 > -- >=20 > For archives and unsub = http://mail.lancaironline.net:81/lists/lml/List.html --Apple-Mail-13--518875653 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii
It is simple and self-contained, mechanical, no = electrics.
It's just a wind vane that tells you what the AOA = of the wing is, no matter what.
I calibrate it by doing some = stalls while watching where it is poijnting at the break, and then mark = the angle with automotive pinstriping tape... mark a second mark AOA for = best rate of climb, or whatever angle you want.
The actual = angle in degrees is irrelevant.
It was reassuring when I took = off once and the pitot line pulled off.  Just flew the = AOA.
Also makes steep turns on final no-sweat.  I can fly = a few degrees below stall AOA in any attitude, any airspeed, temp or = turbulence.
IMHO the AOA with lights are only accurate usually = to about 3 or 4 degrees and don't tell you how far above -- above -- = stall you are, where as the little Bacon Saver tells you exactly to what = angle to pitch the wing down to recover from a stall, for minimum = altitude loss.
Mine's mounted into a tube I bonded to the rib = at the end of the wing stub, removable with a taped-on 3/32 flush rivet = through the tube.
Any questions or suggestions are welcome. =  Make one yourslef, and get an AOA on your plane, and take the = sweat out of slow flight  or high AOA = flight.
Terrence
L235/320 = N211AL


On Jan 12, = 2010, at 6:44 PM, marv@lancair.net= wrote:

Posted for Jeff Peterson <jeffreyb.peterson@gmail.com>:

 If you are interested in homebuilt angle of attack = systems
 you might want to read this thread on rec.aviation.homebuilt
 
 http://groups.google.com/group/rec.aviation.homebui= lt/browse_thread/thread/bc8acb7472d0698e/dfc062e386e86a01?hl=3Den&lnk=3D= gst&q=3Dangle#dfc062e386e86a01
 
 I was surprise how many people are interested in the = subject.
 
 before building your own it pays to look at = the
 variety of commercially available system out there.
 Two that use = differential pressure systems are
 
 Advanced Flight = Systems and
 Alpha Systems.
 
 and several efis units = now include some kind of AOA.
 
 I have not flown with = any of these but have collected a few opinions:
 The audio beep output = of the Alpha is very effective...gives continuous
 feedback = during any high AOA operation, but with eyes outside.
 The Alpha LED = display looks cheap and clumsy (my opinion).
 The AFS unit is = cumbersome to set up in the cockpit and requires probes
 built in to the = wing.
 The AFS Pro display looks quite nice but is also pretty large.
 
 
 
 I did breadboard my own = design which has heartbeat audio feedback,
 and a smaller = display that either of either these units. I plan to use the
 Dynon heated = Pitot/AOA probe.
 My own work is not well enough along for me to
 post schematics. I will post, if I get it working = well.
 
 Cheers,
 
 --
 Jeff Peterson
 LNC2 N273CK

--

For archives and unsub http://mail.=
lancaironline.net:81/lists/lml/List.html

= --Apple-Mail-13--518875653--