 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
mppalmer(at)aol.com
Guest
|
 Posted: Tue Jun 12, 2012 8:16 am Post subject: AOA |
 |
|
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.
| | - The Matronics Glasair-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Glasair-List |
|
|
|
| Back to top |
|
 |
grosseair(at)comcast.net
Guest
|
|
| Back to top |
|
|
Alpha Systems AOA
Joined: 11 Jun 2012
Posts: 3
Location: Ramsey, MN
|
| Posted: Tue Jun 12, 2012 12:00 pm Post subject: Re: AOA |
|
|
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
| | - The Matronics Glasair-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Glasair-List |
|
_________________
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 |
|
| Back to top |
|
|
BGray(at)glasair.org
Guest
|
| Posted: Tue Jun 12, 2012 12:24 pm Post subject: AOA |
|
|
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
--
| | - The Matronics Glasair-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Glasair-List |
|
|
|
| Back to top |
|
|
grosseair(at)comcast.net
Guest
|
| Posted: Fri Jun 15, 2012 11:38 am Post subject: AOA |
|
|
Since you're not getting much of a response here, you might try your
question on the www.glasair.org list. That's the list to which most
Glasair owners and builders subscribe.
John Grosse
| | - The Matronics Glasair-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Glasair-List |
|
|
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
