Today's Message Index:
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1. 09:16 AM - Re: AOA (mppalmer@aol.com)
2. 09:44 AM - Re: Re: AOA (John Grosse)
3. 11:45 AM - Gl2SFT (Craymondw@aol.com)
4. 01:01 PM - Re: AOA (Alpha Systems AOA)
5. 01:24 PM - Re: Re: AOA (Bruce)
Message 1
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I would like to have an AOA indicator in our plane. I agree it is truly
a direct indicator of stall. But as I wrote in an earlier post, I was a
beta tester for the Rite Angle AOA and we couldn't get that work
properly on the Glasair.
The Rite Angle uses a conventional mechanical vane to detect AOA. Not
as glamorous as differential pressure and stuff, but dirt simple. If
you can't get a vane to work, it's not likely a fancy pressure port
will work either. (You don't have static port problems with a vane.)
As I had written earlier, I mounted the vane on a streamlined tube
about 6 inches below the wing, off an inspection cover. As I approached
stall, the AOA would increase ... and then hold. (Or sometimes
decrease!) Elbie and I thought the probe would have to be located much
further away from the Glasair wing to be clear of bow wave. Or much
more forward.
I recall Lyle Powell writing in the GlasairNews about some trick way to
determine AOL with holes drilled in the leading edge of the wing
feeding an airspeed indicator. I met some folks at OSH after that who
tried it but never could get that to work right either.
Anyway, you can understand my reluctance to part with a lot of money
for an AOA if it won't work in our situation. But I'm willing to be a
beta tester of sorts for the Glasair if Alphasystems is willing to work
with me on it.
Mike Palmer <><
============
I was reading a post about some Glasair owners having trouble
determining an airspeed at which their planes stall. I don't have an
answer as to why this is occurring but I would like to suggest the use
of and angle of attack indicator. Air speed is a result of angle of
attack. Alpha Systems AOA has an angle of attack system that takes
differential air pressure through a probe mounted in an existing
inspection port under the wing, converts that differential air pressure
to an electronic signal through an interface module which is then in
turn displayed on a color indicator(bar graph or chevron style) mounted
on top or under the glare shield or in the instrument panel. The use of
angle of attack is extremely useful since airspeed is often inconsistent
especially at low indicated airspeeds and requires a pilot to calculate
airspeeds mentally as conditions such as density altitude, gross weight,
etc., change. This system calibrates to Optimum Alpha Angle or OAA
which is roughy 1.25-1.3 Vso which is a slow flight airspeed in which a
plane is not climbing nor sinking and has full control surface
authority. Utilizing this system will create a wider safety envelope
for all pilots.
Message 2
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Quite a few Glasair pilots have installed the Advanced Flight Systems
AOA with good success.
http://www.advanced-flight-systems.com/Products/AOA/aoa.html
John Grosse
Message 3
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In 1957 a college acquaintance asked me if I was interested in kicking in
$10.00 for AV gas on a flight home from Angola, Indiana to White Plains New
York in his souped up Piper Tri Pacer. Soon after reaching altitude and
heading the pilot reported that he was up all night studying for his
engineering finals and said he couldn't keep his eyes open and asked if I would
fly
the plane while he napped. He added that I follow the highway that ran east
and pointed at the altimeter and said "keep the needle pointing at this
number." Prior to that my only flying experience was a ride in a J3 Cub. The
pilot was soon fast asleep and I was gingerly feeling out the controls
trying to teach myself to fly as smoothly as I could. I spent the following
two years flying VFR round trips with this teen in some of the worse weather
conditions I have ever flown in. On one such return trip we were over Oil
City Pennsylvania one mid night in a blinding snow blizzard with me working
the navigation finder when he had an admitted case of vertigo and got the
plane in a spin. It wasn't until we spun out of the base of the cloud he
applied the proper controls. Believe it or not I wasn't alarmed and thought if
it happened again he got us out the last time! Beginning in the late
1970's I became interested in aerobatics and took well over 100 hours in
lessons from Jim Parker, Daniel Heligon, Dave Sayles and Top Gun Alex Alexander.
Over the years I have flown close to two hundred different makes and models
of aircraft ranging from home built's, war birds to jets and have come to
the conclusion that the simpler and lighter the plane the safer. My angle
of attack indicator is my left hand and during flying off my first twenty
five hours I took my plane up to altitude and started feeling out the plane
performing mild aerobatics and stalling the plane in various attitudes. This
was when I noticed my Glasair has a sudden nose down pitch using the
rudder. During the construction phase I placed leading edge strips on the
wings. I learned my plane buffets and rumbles as it goes into a stall and
continues buffeting and doesn't drop a wing. Just for kicks I set the plane up
in
a buffeting full stall with an instructor, the late David Darnel and kept
it there while dropping a few hundred feet to demonstrate to David how well
the plane performs in a stall.
The deciding factor in building a Glasair was how over built the structure
is, the composite air frame is virtually maintenance free and to have the
same performance and looks in a factory built I would have to have spent
hundreds of thousands of dollars more. Where can you buy a factory built with
the performance of Glasair One's and Two's in the $70,000 range?! Since
1991 my biggest pleasure has been over hearing novices say; "That isn't a
factory built? "
Chuck Raymond
Message 4
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I'm sorry to hear of your poor experience with the Rite Angle AOA but I'm not surprised. That system still uses old technology, a vane with a potentiometer and inferior internal board components. The Alpha Systems AOA has no moving parts and uses the highest quality internal components and is subject to rigorous testing before delivery to the customer. "If you can't get a vane to work, it's not likely a fancy pressure port will work either. (You don't have static port problems with a vane.)" Quite the contrary, there is nothing fancy about Alpha Systems differential air pressure probe. As a matter of fact it's very simple and that's the beauty of it. The probe utilizes an existing inspection port and extends below the wing approximately 3" which is no further than a pitot tube. The Alpha Systems AOA is a stand alone system that does not share the pitot/static system which provides redundancy in the event of pitot/static damage or blockage and failure. Not to mention the Alpha Systems AOA is not subject to postion error because of the utilization of differential air pressure. Alpha Systems AOA is installed in several Glasairs with great satisfaction and no known problems to my knowledge. Another thing I want to be sure is clear in this discussion of AOA is we are not targeting stall. We can't set the AOA for stall because it is constantly moving number based on a number of factors. We are displaying a range of Alpha from level flight to Optimum Alpha Angle which is roughly 1.25-1.3 Vso. Here are a couple of links to see the Alpha Systems AOA in action. www.ballyshannon.com and www.alphasystemsaoa.com
--------
Chris Crosby-CFI, CFII, CSIP
Sales/Technical Support
Alpha Systems AOA
763-506-9990 or 877-571-3770 ext.-205
chrisc@depotstar.com
www.alphasystemsaoa.com
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=375436#375436
Message 5
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Can't target stall? That's what an AOA does. A wing always stalls at the
same AOA. While the IAS will vary some according to weight, the AOA will
always be the same.
Bruce
WWW.Glasair.org
-----Original Message-----
From: owner-glasair-list-server@matronics.com
[mailto:owner-glasair-list-server@matronics.com] On Behalf Of Alpha
Systems AOA
Sent: Tuesday, June 12, 2012 4:00 PM
Subject: Glasair-List: Re: AOA
<chrisc@depotstar.com>
I'm sorry to hear of your poor experience with the Rite Angle AOA but
I'm not surprised. That system still uses old technology, a vane with a
potentiometer and inferior internal board components. The Alpha Systems
AOA has no moving parts and uses the highest quality internal components
and is subject to rigorous testing before delivery to the customer.
"If you can't get a vane to work, it's not likely a fancy pressure port
will work either. (You don't have static port problems with a vane.)"
Quite the contrary, there is nothing fancy about Alpha Systems
differential air pressure probe. As a matter of fact it's very simple
and that's the beauty of it. The probe utilizes an existing inspection
port and extends below the wing approximately 3" which is no further
than a pitot tube. The Alpha Systems AOA is a stand alone system that
does not share the pitot/static system which provides redundancy in the
event of pitot/static damage or blockage and failure. Not to mention!
the Alpha Systems AOA is not subject to postion error because of the
utilization of differential air pressure. Alpha Systems AOA is
installed in several Glasairs with great satisfaction and no known
problems to my knowledge. Another thing I want to be sure is clear in
this discussion of AOA is we are not targeting stall. We can't set the
AOA for stall because it is constantly moving number based on a number
of factors. We are displaying a range of Alpha from level flight to
Optimum Alpha Angle which is roughly 1.25-1.3 Vso. Here are a couple
of links to see the Alpha Systems AOA in action. www.ballyshannon.com
and www.alphasystemsaoa.com
--------
Chris Crosby-CFI, CFII, CSIP
Sales/Technical Support
Alpha Systems AOA
763-506-9990 or 877-571-3770 ext.-205
chrisc@depotstar.com
www.alphasystemsaoa.com
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=375436#375436
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