Stick shaker

[raytoews]

I have had my stick shaker installed in my Grumman for about a yr now and have gotten very used to it. Recently I did a photo mission for a friend and we spent an hour with the canopy back at 1k ft and just above the stall speed. I felt very comfortable "flying the shaker". I have it set about 5 knots above stall and while busy looking at our targets my attention was never diverted away from outside.
If I had an AOA I would have had to keep my eye on it the whole time.
I understand the industry is trying to sell another must have accessory but as for me and my airplane, we are going to look out the window and when we get a little slow I will feel the buzz just before the wings start to shake and things go wrong.
The little vibrator motors are all over ebay for less than 10 bucks, clamp it to your column, hook it to your stall horn.
Don't fall.

Ray Toews
Fort Vermilion AB

[rv7charlie]

Go for the AOA. Hook your stick shaker to that. Then, no worries whether you're light or heavy.

[wyoranch]

Go for the AOA. Hook your stick shaker to that. Then, no worries whether you're light or heavy.
+1

[rwanttaja]

Sounds like a good entry for the contest:

http://www.eaa.org/en/airventure/eaa-airventure-news-and-multimedia/eaa-airventure-news/2015-eaa-airventure-oshkosh/07-22-2015-eaa-founders-prize-to-accelerate-safety-innovation

(Pssst Hal: The http://www.foundersinnovationprize.org link in the above press release doesn't work....)

Ron Wanttaja

[Ron Blum]

Ray: Great post and good use of low cost technology that works well! Ironically, your post shows the strong need for education on AOA. Your stall horn is AOA-based. In technical terms, the certificated (probably Safe Flight) vane/flipper switch makes electrical contact when the stagnation point goes below/behind it. This makes the horn go off (... and in your case, the stick vibrate). Good use of technology :o) and thanks for sharing!

[raytoews]

I would love to claim it but I read about it on the VAF. I like the Safe Flight vane, adjust it for 5 k above stall speed. Aircraft Spruce has them for $165. I'm installing one in my new Zenair wings. Different weights change the stall speed but it still goes off at the same angle.
AOA that I have researched don't seem to work with flaps and if they do they use a calibrating computer to provide a bias. More stuff to go wrong. The ones with the vane on the side would work, but a prop on the nose makes that difficult. Has to be mounted under or in front of the wing. Works fine on jets.
Back in my 417 SQN days that was one of the pre takeoff checks, move one vane, the pilot felt the shake, go around the other side and it kicked.
The AOA's with the air pressure sensing would be fussy to adjust. My MGL EFIS has a diagram to drill two holes in the leading edge, unobtrusive but not easily adjustable. Also the air pressure ones would need some type of electronics to send 12 volts?? to a gauge.
This is one of those things that should be installed in every spam can out there, most of them have the little paddle switch already, (except some Cessna's which used the air horn). Easy to hook up, I just wired mine to the stall horn, 1/2 hour job, cost me $8. My Cheetah is OM so I just made an entry in the log book. No gov't oversite.
The way it should be.
Ray

[Ron Blum]

Ray: Agree with all you say. No AOA will work with flaps as you mentioned, though. Ironically, the stall AOA does change with flaps (so a flap input is required) ... the stall AOA is LOWER with flaps. So one could get around this issue if they set a single input AOA system up by using the flaps DOWN data. It would be conservative for flaps UP.

[cluttonfred]

This would be a great project for a little Arduino microcontroller using tiny haptic (vibrating) motors like these installed directly in the stick grip(s) or yoke(s) along with a visual indicator (bright flashing LED?) at the top of the instrument panel.

5078 5079

http://www.adafruit.com/products/1201

For a flapless plane you could use a homemade vane- or paddle-type AOA with a single contact switch at the critical angle. For a flapped plane you would need a more sophisticated AOA sensor with a potentiometer to provide variable AOA indications, and some way of determining flap position, perhaps another potentiometer connected to the flap handle, crank or indicator if there are multiple flap positions or just a couple of contact switches if you only have two or three possible positions.

The Arduino microcontroller needed for such a simple application would only run about $10, so the whole project would only cost about $25-50 including the option of a small battery backup. It could even be used in a plane without electrics with a 9v battery or little rechargeable battery pack.

[raytoews]

Thatis very cool.

Slip it under your rubber grip so it buzzz's right into your hand.
That will be the next one I do.
No need for electronics, a wing stalls at 15 degrees, weight just changes the speed at which it stalls.
When the buzzzer goes off you are at fifteen degrees, it startles you,,,, you push and don't die.
KISS works.
This is one of those simple things the govt should approve NOW with no restrictions.
Is there anyone from Transport Canada, the FAA or ICAO out there? Get off your fat borocratic ass and do something productive,,,,,today!
They want to keep us safe from ourselves,, do something to reduce the loss of control accidents, this will do it.


But I digress,,,,

Ray

[Ron Blum]

Is there anyone from Transport Canada, the FAA or ICAO out there?



Yes. FAA, TC, EASA and ASTM. We're working on it ... just need to get it through the government lawyers.

[cluttonfred]

Thatis very cool.

Slip it under your rubber grip so it buzzz's right into your hand.
That will be the next one I do.
No need for electronics, a wing stalls at 15 degrees, weight just changes the speed at which it stalls.
When the buzzzer goes off you are at fifteen degrees, it startles you,,,, you push and don't die.
KISS works.


Feelings about bureaucrats aside, I agree that you don't need any fancy electronics for a flapless plane, just wire the shaker and light to the contact switch on the vane or paddle AOA sensor, power it with a 9V battery, maybe add a "push to test" button to check the battery during your preflight, but how would you adjust for flaps up/down when a plane does have flaps?

[2ndsegment]

Have you looked at the MCAS on the 737 MAX or the rudder pedal shaker on the F-4J? The tailhook flyers of the Navy fly AOA regularly for carrier landing where they can look out of the cockpit and see that the little vane is still there and moving correctly.

[Ron Blum]

Have you looked at the MCAS on the 737 MAX or the rudder pedal shaker on the F-4J? The tailhook flyers of the Navy fly AOA regularly for carrier landing where they can look out of the cockpit and see that the little vane is still there and moving correctly.

One can actually see the vane from the cockpit?

So are you saying that the stall warning is shaking rudder pedals?

Thanks, Ron

[2ndsegment]

Just to be more public- Stalls Stalls are primarily a factor of angle of attack. The F-4 will provide several stall warning cues that are discussed in the following paragraphs. The aircraft comes equipped with a rudder pedal shaker that activates at a fixed threshold and warns the pilot before approaching stall angle of attack. Tthe angle of attack at which the pedal shaker is activated is dependent on aircraft type as listed below. class "wikitable" pedal shaker activation - aircraft angle of attack - early f-4b aircraft 22.3 - late f-4b and f-4n aircraft 21.3

Pedal shaker activation – Angle of Attack



Early F-4B aircraft

22.3 units



Late F-4B and F-4N aircraft

21.3 units

[2ndsegment]

Just to be more public- Stalls

Stalls are primarily a factor of angle of attack. The F-4 will provide several stall warning cues that are discussed in the following paragraphs. The aircraft comes equipped with a rudder pedal shaker that activates at a fixed threshold and warns the pilot before approaching stall angle of attack. Tthe angle of attack at which the pedal shaker is activated is dependent on aircraft type as listed below. class "wikitable" pedal shaker activation - aircraft angle of attack - early f-4b aircraft 22.3 - late f-4b and f-4n aircraft 21.3

Pedal shaker activation – Angle of Attack



Early F-4B aircraft

22.3 units



Late F-4B and F-4N aircraft

21.3 units




and from PRUNE

For instance, in the Harrier, if more than a 10°angle of sideslip exists, the aircraft can enter into an uncommanded roll,which can be unrecoverable. To prevent this hazard, the Harrier uses aweathervane-type probe extending into the airflow in front of the cockpitwhich measures angle of sideslip. The weathervane-type probe aligns withthe relative wind, allowing the aircraft to determine angle of sideslip bymeasuring the difference between the rotational position of theweathervane-type probe and the normal alignment of the body of theaircraft with the airflow. In the Harrier, if the angle of sideslipbecomes excessive, a warning is provided to the pilot by a pedal shakerwhich shakes the rudder pedals. The pilot can also visually monitor theangle of sideslip by observing the amount of angular offset of theweathervane probe. However, the Harrier's weathervane probe is fixed inplace even when the Harrier is in normal wing borne flight. This increasesthe drag of the Harrier at higher speeds.

[2ndsegment]

an F-18 use of AOA in a video
https://www.bing.com/videos/search?q=video+of+aoa+vane+in+carrier+landing&&view=detail&mid=9609637DD6BF338737E29609637DD6BF338737E2&rvsmid=2D05E681405BB4DAADC92D05E681405BB4DAADC9&FORM=VDQVAP

[2ndsegment]

then on a carrier instead of an airfield.

https://www.bing.com/videos/search?q=video+of+aoa+vane+in+carrier+landing&docid=608049076768344902&mid=2D05E681405BB4DAADC92D05E681405BB4DAADC9&view=detail&FORM=VIRE

[2ndsegment]

A sketch and a picture the AOA vane is about where the pilot is looking. I am stll looking for a picture of it as seen from the cockpit I saw a long time ago. In the first video above the little brown focus grabber went down to about where it is on the FA-18 at one time in the video.
8366 8367