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stall warning

L

LIMA HOTEL

Active Member
Does anyone know the source (generator) of the stall warning tone we hear in our headphones? I believe it is the Dynon EFIS. If the Dynon fails do we not have at least a stall warning? If this is true and those of us that are E-LSA and have no steam gage airspeed backup ( I know there is a group of "gages" on a page of the Garmin GPS, but that is ground speed), how about having a stall warning light tied in to the stall switch also or a different, independent, tone generator? Or does the tone come from some wizardry in the integrated fuse/switch panel that is relatively fail safe?
Larry
 
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Stall Warning

I plan to install a Lift Reserve Indicator (LRI) after my airworthiness inspection. I have used one for the past 12 years or so in my now-sold RV6A and really depended on it...no electricity needed or moving parts except the indicator needle...since I don't plan to be removing and reinstalling the wings over and over the two pressure tubes from the LRI's probe should not be a problem. The feature that I liked was that the LRI indicates how FAR AWAY from stall you are, and of course, when you are about to lose it. Makes no difference what your attitude is, how CG is, or what your weight is...simple and pretty fool-proof.
 
OK, I answered my own question. With just the master switch on (avionics switch off), the stall warn tone sounds.

The LRI looks like a really good idea and it is a lot better than Dynon's AOA because it will work if the EFIS fails. Unfortunately it won't fit in the most desirable spot in the ELSA panel (in front of the pilot). I suppose even way over to the right is better than not having it. My panel will have the optional second Dynon (because I want to dedicate the engine instruments on it) and the LRI would have to go WAY over to the right if it would fit there. See the picture of the complete optional panel on Van's website under the RV12 heading and the specifications page.
 
LRI Location

If possible I will put the LRI on top of, not in, the panel. That way you can see it within your peripheral vision without taking your head away from the outside...particularly important, to me anyway, when making tight turns in the pattern...I can keep my head out of the cockpit at important times. Worked just fine for me.
 
I have seen and flown a retangular LRI that has LEDS for indicators. Like JohnF said you can pick it up in your periferal site and don't have to take your eyes off the runway. Very useful for short field landings, accurate.

I can't find the supplier of the LED LRIs, anyone know if they are still around? Very cool product.

They look something like this. http://www.aircraftspruce.com/catalog/inpages/alphaSystems.php
 
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Here is where to buy the best ones I have seen. The company is great to deal with and I have been totally satisfied with their product. I have several friends that bought from them as well that are equally pleased. Great company, the owner himself will talk to you and he has a cool booth at the big shows to demonstrate all the various products.

http://www.alphasystemsaoa.com/

(877) 571-3770
 
John,
You won't put the LRI you are talking about above the panel in a 12 because the top of the panel is on the outside of the plane!
Larry
 
LIMA HOTEL said:
Does anyone know the source (generator) of the stall warning tone we hear in our headphones? I believe it is the Dynon EFIS. If the Dynon fails do we not have at least a stall warning? If this is true and those of us that are E-LSA and have no steam gage airspeed backup ( I know there is a group of "gages" on a page of the Garmin GPS, but that is ground speed), how about having a stall warning light tied in to the stall switch also or a different, independent, tone generator? Or does the tone come from some wizardry in the integrated fuse/switch panel that is relatively fail safe?
Larry
Click to expand...

To answer the original question...the stall warning tone is generated on the switch panel.

As long as their is aircraft power you should still hear the tone. Even without the Dynon or the intercom powered on.
 
Before I installed any LRI stuff I would finish the plane and fly it as designed. By the time you get done with all the stalls required on the test card, you will be convinced that a stall in the 30's knot range is most unlikely in everyday flying. Plus when it does stall (takes forever) it falls foward and recovers as soon as you let go. It was obviously designed with all these concerns in mind

Fly the card before you spend anymore money (or weight) on more stall info.
 
AOA versus air speed

A stall can occur at various air speeds that are much higher than normal, depending on several factors like bank angle and weight. For each flap setting, a stall only occurs at one angle of attack. Many pilots have spun in while approaching to land because they did not realize that their plane would stall at a higher speed. An air-speed indicator is good for calculating winds aloft. AOA is good for preventing stalls and for establishing the best rate of climb or descent. Comments are welcome from Navy pilots.
Joe
 
Navy pilots fly carrier landings, in the dark, in thunderstorms, have ejection seats and wear parachutes. Most 12 pilots won't be. Cirrus tried to build the "can't crash it" airplane and look where they got with that. Just saying I wouldn't start adding "more" stuff until I at least flew off the test cards.
 
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