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Re: REFLECTOR: AOA perspective
> What about you Velocity fliers (if any of you have read this far)? =
> Would you like to have one of these on your airplane? I'd like your =
> feedback, because I'm giving serious thought to making this =
Yup, read that far.
Well, yes, I would like an AOA meter in my bird. I don't know if it's
usefulness will be warranted. I'm doing it "because I can", and this
airplane is really experimental in many ways.
Yes, I have an AOA meter installed. I went to the NASA DFRC server
and latched on to their RT-FADS papers. RT-FADS stands for
Real Time - Flush Air Data System. They tested theirs on an F-18
at speeds in excess of mach one. They use the system on their heavy
high speed bombers and the Space Shuttle.
I installed mine on the nose of the airplane. I have seven ports
arranged vertically. One in what I figure to be the leading edge
(and thus the stagnation point) of the nose, and then three more above
and three more below it. I am going to use those cool, really
sensitive micromachined strain gauge sensors that you can get on
an IC. They cost about $10 each. I'll connect these to an
analog multiplexer, which then feeds into a cheap ($100) embedded
microcontroller from Z-World. It will talk on my RS-485 multi drop
network that is connected to the main computer.
Calibrating this puppy will be the tricky part. I figure I will require
a traditional van AOA type meter to collect reference data. I'll
wash all the data through a neural network simulator and generate
a mathematical model that will live on the Zworld controller.
You can't just plug in a single model and expect to get accurate AOA.
The pressure distribution is not constant over a range of speeds. In
other words, you have to do a multi variable regression analysis
to get it to work. However, I've seen the math. It's not for the
faint at heart. A neural network will do the same thing, and better
yet, it is deterministic, and will do interpolation naturally.
Yes, I like this sort of thing. Not sure if it's going to be useful,
but ain't it cool?
Brian Michalk <http://www.awpi.com/michalk>
Life is what you make of it ... never wish you had done something.
Aviator, experimental aircraft builder, motorcyclist, SCUBA diver
musician, home-brewer, entrepenuer and SINGLE!