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Re: LRI

Subject: Re: LRI
From: Gerry Holland <gnh@ddsc.demon.co.uk>
Date: Sat, 14 Nov 1998 17:44:49
Erich

Its all about stall condition .awareness

The Website is at:

http://www.liftreserve.com/


Another site offering an Angle of AttacK device is at:

http://www.angle-of-attack.com

An overview is as follows in answer to my questions re device.

Look at the Website as an AOA indicator is shown......

"The retail cost of the AOA Professional is $1,450.  As a comparison the
A/C Spruce simple stall warner switch and buzzer sells for $1,200.  Our
AOA includes a four color digital display, voice warning system, landing
gear warner and RS-232 port.   


As you may have seen at www.angle-of-attack.com, the red chevrons
indicate AOA's near the critical AOA  (verbal warning  "angle angle
push"), the donut is only on if the flaps are in the landing
configuration, the donut is used for the target AOA for the optimum
approach AOA,  the "X" on the green bar is the best glide AOA or the
maximum endurance AOA.  The digits at the bottom are units of AOA which
are approximately in tenths of a degree.  When the display reads 000 you
are at zero degrees from zero lift which is where your aircraft will
accelerate the fastest for any given power setting.  AOA is it
aerodynamically and is used to fly Vx, Vy, L/Dmax, maximum endurance,
etc!!  You know exactly where you are relativeto a stall during short
field appproaches regardless of weight, density altitute, bank angle or
turbulance.  As you know IAS stalling speeds vary depending upon wing
loading, bank angle, fuel load, CG, etc while allapproaches should be
shot at the same AOA regardless.  AOA's fidelity increases at high AOA's
and low airspeeds while the IAS's fidelity actually decreases. 

The AOA Professional installation requires pressure port in the top and
bottom of the wing towards the wing tip and also uses dynamic pressures
---From your pitot static system.  Our patent pending AOA takes advantage
of the aerodynamic fact  that; dividing the wing pressures by the
dynamic pressure results in a coefficient of pressure  known to vary
uniquely with AOA. There are no protrusions or moving parts to increase
reliability.  Thenext cheapest full range true digital AOA is $22,000
and it does not include a voice or digital colored display.

Future projects include the AOA Sport due for release in March 99 and
will feature a simpler but smaller LED ladder display, no gear warner or
RS-232 port but retains the voice warning system.  Price will be about
the same as the LRI you were looking at. 

The other question you should ask is, "With the airspeed held constant,
does the AOA increase with an increase in bank angle?"  Both the AOA
Professional and Sport are true AOA's guaranteed.

Snail mail could be on the way tomorrow if you forward your address.  I
could demo the AOA Professional and Sport if our schedules meet in
December.  I'm in Excelsior just west of the twin cities.

Jim@angle-of-attack.com
(612) 474-4154

Gerry Holland
Intranet Solutions Inc.
gnh@ddsc.demon.co.uk
gerry.holland@intranetsol.com
Mobile  +44 (0) 374 755889
Office  +44 (0) 1761 435706
Fax     +44 (0) 1761 432472


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