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It is an interesting product with some clever ideas, but a very poor implementation. It is unlikely that it will keep working reliably for long in the real-world/real-aircraft environment.
The system does not take into account flap deployment. Anyone here use flaps?
The "normal" position of the probe is with the Hall sensor at the zero point of the magnet. Anyone concerned about the fact that the system could report "normal" output if the probe or the magnet falls off?
Even the most rudimentary analysis of the Hall sensor's output as its temperature varies from -20C to +50C would reveal a potential for some worrisome inaccuracies. You could stall several LEDs before you expect to, or you could be several LEDs away from a stall when the system says you should be stalling. Would you be more or less likely to actually stall in these situations?
The design does not take into account the fact that each LED that is on will cause the main IC's temperature to rise by about 15C. A little slow flight practice with a 6 LEDs on and the IC is well past its 100C limit, generating a burning smell and possibly smoke. Same would happen after an engine out as you glide down at best glide speed. Can you think of a worse time to find smoke in the cockpit?
This is just a partial list of issues, but I think it gets the picture across. The only thing worse than not having something is having something that is not reliable.
Regards,
Hamid
Gary Fitzgerald wrote:
He has an article on this project in the Dec. 2008 edition of Sport
Aviation. Interesting use of a Hall Effect sensor.
Gary Fitzgerald
LNC2 extra-slow build ~70%
engine: TBD
St. Charles, MO
----- Original Message ----- From: "billhogarty" <billhogarty@hughes.net>
To: <lml@lancaironline.net>
Sent: Sunday, January 03, 2010 3:08 PM
Subject: [LML] Do-it-yourself AOA Project
For those folks that liked the do-it-yourself Automatic Engine Dryer
Project article written by David Barker in the October issue of the EAA
Sport Aviation magazine, there is another do-it-yourself project on the
web for a $ 50 Angle of Attack indicator that mounts on the pitot tube.
Check out "barkeraircraft.com".
Happy New Year, Bill Hogarty
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