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  #1  
Old 05-18-2020, 09:27 PM
Vac Vac is offline
 
Join Date: Jul 2009
Location: Niceville, Florida
Posts: 491
Default Wind Shear Video

We were flying some AOA software tests last week and had a camera installed to record the standby airspeed indicator along with the normal forward view. My home base is a tree canyon close to the Gulf Coast 5 miles east of Eglin AFB in the Florida Panhandle. Winds were light on the surface (80’ MSL), variable around 090 degrees or so at takeoff, but I encountered over 30kts at pattern altitude. As I climbed through about 3500’ MSL, winds dropped off to light and variable. This abrupt shift in velocity in such a small altitude band meant the chance for wind shear would be high during RTB, and sure enough, it was: https://youtu.be/0RiB6_8bx3c

The important thing to note is how rapidly the bottom dropped out in the transition and flare. Stable is a relative term under these conditions in a light plane. I was flying a slight fast approach (high rate beeps of the tone) and transitioning to ONSPEED during transition to landing. The AOA tone provided good SA throughout, but it was sporty. If 15 kts of rapid shift is “severe” wind shear, this event was close. If shear results in a rapid loss of airspeed, it’s called “performance decreasing” and if it causes a rapid increase in airspeed, it’s called “performance increasing.” The recent Van’s EAA webinaire addressed this and I’d recommend it to anyone that hasn’t watched it. If you’d like more info on our AOA work, visit our site at http://www.flyonspeed.org

Fly safe,

Vac
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Last edited by Vac : 05-19-2020 at 12:46 AM. Reason: Used less words
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  #2  
Old 05-18-2020, 10:03 PM
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Gash Gash is offline
 
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Good video. Thanks for sharing this Vac.
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  #3  
Old 05-19-2020, 12:00 PM
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rv8ch rv8ch is online now
 
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Default tailwind?

Always enjoy your videos! Looks like you had a tailwind if I'm looking at this right:

https://youtu.be/0RiB6_8bx3c?t=97
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  #4  
Old 05-19-2020, 12:04 PM
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Pilot135pd Pilot135pd is offline
 
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Location: Vaca Moo Airport - TA37 in East TEXAS
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Quote:
Originally Posted by rv8ch View Post
Always enjoy your videos! Looks like you had a tailwind if I'm looking at this right:

https://youtu.be/0RiB6_8bx3c?t=97
That caught my eye too and I looked at the windsock many times in slow motion but my laptop doesn't do slow motion good enough to be sure.
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  #5  
Old 05-19-2020, 12:07 PM
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Pilot135pd Pilot135pd is offline
 
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Location: Vaca Moo Airport - TA37 in East TEXAS
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Default

Quote:
Originally Posted by Vac View Post
We were flying some AOA software tests last week and had a camera installed to record the standby airspeed indicator along with the normal forward view. My home base is a tree canyon close to the Gulf Coast 5 miles east of Eglin AFB in the Florida Panhandle. Winds were light on the surface (80? MSL), variable around 090 degrees or so at takeoff, but I encountered over 30kts at pattern altitude. As I climbed through about 3500? MSL, winds dropped off to light and variable. This abrupt shift in velocity in such a small altitude band meant the chance for wind shear would be high during RTB, and sure enough, it was: https://youtu.be/0RiB6_8bx3c

The important thing to note is how rapidly the bottom dropped out in the transition and flare. Stable is a relative term under these conditions in a light plane. I was flying a slight fast approach (high rate beeps of the tone) and transitioning to ONSPEED during transition to landing. The AOA tone provided good SA throughout, but it was sporty. If 15 kts of rapid shift is ?severe? wind shear, this event was close. If shear results in a rapid loss of airspeed, it?s called ?performance decreasing? and if it causes a rapid increase in airspeed, it?s called ?performance increasing.? The recent Van?s EAA webinaire addressed this and I?d recommend it to anyone that hasn?t watched it. If you?d like more info on our AOA work, visit our site at http://www.flyonspeed.org

Fly safe,

Vac
Yet another reason to use the AOA tones....instead of looking at airspeed when landing.
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Sadly sold my RV-8 however still trying to enjoy life by living on my airport with FREE campsites for pilots to enjoy www.facebook.com/VacaMooAirport/ & flying my OnSpeed equipped C-177 while waiting for the RV15 !

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  #6  
Old 05-19-2020, 12:14 PM
Vac Vac is offline
 
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Location: Niceville, Florida
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Mickey,

Was 090 variable, light at the tree line, near as I can tell. You can see the transition from the crab to the right during final as I descend out of the heavy air. Could have shifted slightly southeast at the surface, no doubt. Interesting ride through the different layers. Eglin reported 050 at 9 a few minutes prior. Daily sea breeze was starting to fill in and winds were beginning to clock southeast out on the water just to the south of both airports.

Cheers,

Vac
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  #7  
Old 05-19-2020, 12:45 PM
Bavafa Bavafa is offline
 
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Looks like I am completely missing it in the video.

I was once in a wind sheer on short final and the experience was completely different than seen in this video OR that at least I can identify it.
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  #8  
Old 05-19-2020, 01:12 PM
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Pilot135pd Pilot135pd is offline
 
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Quote:
Originally Posted by Bavafa View Post
Looks like I am completely missing it in the video.

I was once in a wind sheer on short final and the experience was completely different than seen in this video OR that at least I can identify it.
Did you see the airspeed instantly drop? Hard to do that in a plane without wind shear or an arresting hook, unless you hit something head on !
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Exempt by 3 out of the 10 ways but I still donated.
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  #9  
Old 05-19-2020, 01:49 PM
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N941WR N941WR is offline
 
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I had a similar situation in my -9 a number of years ago during a BFR.

On speed, slight breeze over the trees, as soon as we dropped below the trees I lost all lift. My AoA went from plenty of lift to screaming in my ear.

Full throttle and I left it with a level pitch attitude. I dropped about 30 feet vertically, contacted the ground on the mains, no prop strike and the tailwheel didn't touch. (Thank goodness I don't fly a tricycle gear, or the results would have been much different.) I then bounced back up almost vertical 20 feet, according the witnesses. I had just enough time to firewall the throttle and the power came up just as we touched. I had never seen that before!

I flexed the right gear enough to crack the gear leg fairing.

I didn't call it "wind shear" but I'm sure that is what it is because I went from a headwind to no wind and the bottom just dropped out; plenty of lift to no lift in the blink of an eye. I thought for sure we were dead. The CFI in the right seat was really impressed we were able to fly away. During the debrief, we discussed this at length and he really didn't have anything to say other than being impressed by my quick reflexes as I yelled "STALL" as I shoved the throttle home before he realized what was going on. I honestly think I reacted to the feeling in the stick before I reacted to the tone in my ear.
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Last edited by N941WR : 05-19-2020 at 02:29 PM.
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  #10  
Old 05-19-2020, 02:07 PM
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FORANE FORANE is offline
 
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That's the quality of the 9 we had. It was a handful in gusty windshear type conditions. I had a similar experience with ours. We were halfway out of control; I was moving the stick what seemed like stop to stop trying to maintain proper attitude. We touched down hard; I was concerned the nosegear wouldn't hold. The 9 was a good airplane for us but I didn't like flying it in rough air.
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