X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [67.8.179.94] (account marv@lancaironline.net) by logan.com (CommuniGate Pro WebUser 5.0.9) with HTTP id 1091884 for lml@lancaironline.net; Thu, 04 May 2006 12:20:10 -0400 From: "Marvin Kaye" Subject: Re: [LML] Re: AOA To: lml X-Mailer: CommuniGate Pro WebUser v5.0.9 Date: Thu, 04 May 2006 12:20:10 -0400 Message-ID: In-Reply-To: References: X-Priority: 3 MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format="flowed" Content-Transfer-Encoding: 8bit Posted for "N320GG" : Scott, Earl I took a look at the web site recommended by Scott and read most of the 125 pages of instructions. I like the fact that there is no probe. But of course have even more questions. 1) is the sport model "good enough?" 2) How difficult is it to install in a finished airplane? ( my wing tips are not removable, I would be installing through a hole, like a ship in a bottle.) 3) Would you share pictures of where you installed the ports? So little money, so many wants: ( not necessarily ranked) AOA Gami injectors Light Speed ignition Garmin 396, with XM weather Hard wood floor (Oh wait, that is what she wants!) Gary Melton N320GG [Gary, as you may already know, I worked with Jim Frantz (developer of the AOA Sport and Pro) for several years prior to the sale of that business to Advanced and have a pretty good knowledge of the system. Jim installed the ports for the Pro model (same wing installation for both models) through the access hole for his wingtip lights on his 360. There are no electrics out in the wings, just a pair of polyurethane hoses, each about 1/8" in diameter. If you included a string in the wiring bundle running inside your wiring conduit out to the wingtip (always leave a string for future installations) you can easily pull the hoses through that same conduit, along with a replacement string. While it is easier to work out in the end of the wing through a removable wingtip, it is possible to do the installation through a 1.5-2" access hole, although you will be working with hemostats and other tools similar to those used by arthroscopic surgeons . The ports actually need to be inboard of the actual end of the wingtip by 6-8", to keep them out of the disturbed airflow typically present right at the tip. If that is truly an issue for you it is possible to install the ports inside the access chamber for the airleron belcrank that is just outboard of the flaps... frequently this is a preferable location due to its greater accessibility. If you can't run the hoses within your conduit it is acceptable to run them out that access chamber through a small hole in the aft spar into the area that leads back inside the fuselage just forward of the flaps. Lots of people have done this. The actual recommended location for the ports is in the outboard section of the wing (in front of the ailerons) aft of the leading edge anywhere from 15% to 40% of the chord. While the wingtip location is more easily accessed during construction, installation in that access chamber is perfectly acceptable. The Sport and the Pro both operate using the same algorithms and their performance is pretty much identical... both include the aural stall warning that kicks in about 5 degrees of AOA prior to the actual stall. The Pro includes the aural gear warning as standard, the Sport has it as an option. The visual warnings are similar, although the Pro displays 22 steps between zero degrees AOA and the actual stall AOA, the Sport does the job with 8 steps. Both instruments show specific patterns during cruise, at best L/D, at best approach AOA, at stall-5 degrees AOA (stall warning), and at the stall. The biggest advantage to these AOA devices is that they respond to changes in AOA instantaneously, whereas the ASI lags considerably. This is why a departure following an abrupt pullup after a hi-speed pass can be avoided with an AOA, but not with an ASI. The ASI actually gets laggier the closer the wing is to the stall, whereas the AOA actually improves its definition because of its use of differential wing pressures divided by the dynamic pressure. Most Lancair pilots I've flown with who transitioned into the AOA after having flown for awhile without it have noticed that they actually fly slower approaches simply because they have a handle on AOA and they know where 30% or 40% above the stall is precisely, rather than by guesswork or calculation. The AOA is self correcting for angle of bank, changes in gross weight, temp and humidity, and its port installation locations keep them free of ice and dirt. There are no moving parts and nothing sticking into the airstream to increase drag or get bent, damaged, or frozen. (Just a few things I thought I'd toss on while I was going on and on .) If you have any other questions feel free to ask, I'm pretty sure I can answer them. ]