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AOA indicator poll.
I have developed last year a solid-state AOA indicator, based on a
differential pressure measurement (total pressure/pressure at angle)
Undoubtedly, this is a primary flight instrument to me:
-It shows where you are aerodynamically speaking, independently of
all the variable parameters: Load, flaps position, airbrakes...etc, and
does not need a calculation or interpretation to check if you are
flying right or not... And if the display is well done you will have a
clear indication of the ongoing tendency towards a safe or dangerous
-It give me an accurate indication to adapt the flaps position to stay
at the best glide angle through the whole speed range.
-It is a good indication of the optimal attitude during winch launch
and can prevent a high speed stall at high load factor.
Some pictures of my development are available he
On the video the blinking effect is induced by the camera, the leds
simply fade in or out gradually, only the red one blinks at stall angle
or if the AOA rate of increase will induce a stall within 2 seconds...
you can see that the instrument works as good as its free
The present system includes:
-A 5 leds indicator, red-amber-green-white-blue. The corresponding
AOA for each led is programmed in flight with a push-button.
-An audio input and output: Instead of adding a warning while flying
at higher AOA than the maximum Cz (minimum sink rate), the
instrument hashes the audio output of the vario gradually, cutting
the sound at stall. This is an excellent indication that something is
wrong without adding noise... You can continue to watch outside
while climbing at the best speed, and avoid to enter a spin in the
middle of others.
-A serial i/o for software upgrade and continuous transmission of the
data to another instrument.
-An optional light sensor to adapt the luminosity to the ambient light
level... But the indirect illumination and a better reflector (in
development) has proved that it is probably unnecessary.
The only hardware modification is the installation of an angled
pressure port at a suitable place: angle is not critical, but flow must
be as undisturbed as possible. On the DG I've put mine under the
nose, about 170 mm from the tip, where I had access to the outer
hull from the inside. I drilled a 2 mm hole and glued a small
pressure chamber inside to plug a 4 mm hose. That's all.
Power drain is lower than 20 mA @ 12V, less on ground as no led is
switched on... So no switch, but an internal polyfuse to avoid any
dangerous current drain... So it is simply added to the (fused)
Now as the system proves to be functional and efficient it's time to
do something with it.
Many options are possible:
1) I can order and sell PCB's only, with a BOM and the software...
This is obviously the cheapest way... But components are mostly
SMD... So you need an oven or a lot of patience and skill... Up to
you to make a box adapted to your needs. Price should be about $10
2) I can sell a complete kit with all the components, PCB, software,
connectors and box... Components are not expensive except the 2
pressure sensors ($35 each)... So I should be able to make this for
3) If you prefer a complete instrument, ready to plug-in (except the
pressure port installation) the price should be in the 300-400$
All this depends obviously on quantity... So if I have 1'000 orders it
might be significantly cheaper.
At first I need to know how many people might be interested... And
what is the best option for you.
At least we can fly again in Switzerland and France... So it might
take some time for me to build a website for this product...
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