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Bob_Church

Air Speed

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I'm sorry if this came up earlier and I missed it. If so let me know and I'll delete this and read that.

Has anyone come up with a device for measuring airspeed while under canopy? I've been kicking around ideas but haven't come up with anything I'd want to jump with. In 2014 Ed Vickery came to our reunion and among other things showed us slides of the gear he used when he was developing the Paracommander and getting ready to land a square before anyone else had but I was hoping for something a bit less suicidal looking.

I was wondering about a cup type anemometer but how far would you have to get it from your body to get an accurate reading.

What I'm really hoping is that someone says "they came out with a device that works a year ago, where have you been?"

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Bob_Church


What I'm really hoping is that someone says "they came out with a device that works a year ago, where have you been?"



What you said lol...

I built some parachute flight data recorders for the Forest Service Smoke jumpers several years ago now. It had a pitot tube that measured indicated air speed. It was calibrated in a wind tunnel.

Depending on what you are looking at doing, you may want to look at model rocket / airplane airspeed measurement systems.

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Dutchboy and df8m1, thanks for the input. I didn't know about the new developments with ultralights and model rockets, I'll check it out.
My one plan was to leave my slider uncollapsed and measure the noise coming off of it but calibration would drive me insane.

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Dutchboy

There are some pretty compact systems being used on ultralight. You might have a look at those.



I wonder about something mounted on a strap that could be clipped onto the risers after opening. Maybe something funnel shaped that compresses the air as it leads it to a small propeller with airspeed determined by the electricity it generates as it spins. It would need to be oriented correctly which brings up a few possible problems but also a few solutions so I think that could be overcome. Then have a wire from it going to a video camera so that the air speed is overlaid on the screen letting you review what you did to cause certain speeds and how quickly the results changed, that sort of thing.
I think it could be done. The big question though "can it be done by me" is another thing. Fortunately I still have a lot of friends on campus. Frenchy, in the chemistry department can fabricate anything. He built my smoke brackets for me and is alway making something for faculty and students.

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Some of the base jumpers that are really serious about their wing suit flying have been jumping interments on pilons on their bellies. I think Yuori might have been behind it. You might try reaching him on basejumper.com. As I recall he was able to get actual glide and true airspeed data out of it.

The problem with useing a GPS system is that it's earth frame. It doesn't give you true air speed or decent rate. For a canopy pilot where the speeds are high enough those errors from wind or thermals fade but if you're looking at doing canopy design and trying to verify design models it's a problem. Some people have been using a towed instrument. You lower it on a tail behind you like a towed sonar array on a sub. It's heavy enough that it rides below the wake from your body and gives you good data. The instrument it self is on a pivot and alines with the free stream to give true air speed and decent glide angle in straight flight. I think it uses a free spinning propeller like an anemometer rather then a Pito tube. I think the technology came out of the paragliding industry they are obsessive about their performance. Tried to track one down and had no luck finding it. I think it's some thing used in their development and testing internal to those companies.

Lee
Lee
[email protected]
www.velocitysportswear.com

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I remember this has been discussed before http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=4280100;search_string=Airspeed;#4280100
I think your best bet are sensors for paragliders/hanggliders: they've been using them for decades.
I've also seen paraglider pilots with the sensor on a 'vane' (like Lee described) , so it's always oriented correctly into the airstream. It was a commercial product at the time, maybe from Flytec or Bräuniger?

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WingBug was just introduced at Sun ‘N Fun. It is a portable pitot tube that can be quickly attached to ultralight airplanes via a GoPro like mount. WingBug can be linked to a (cockpit mounted) computer tablet via Bluetooth. WingBug also records key data for download after you land.
You would need specialized software to determine glide ratio (airspeed over rate of descent).

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riggerrob

WingBug was just introduced at Sun ‘N Fun. It is a portable pitot tube that can be quickly attached to ultralight airplanes via a GoPro like mount. WingBug can be linked to a (cockpit mounted) computer tablet via Bluetooth. WingBug also records key data for download after you land.
You would need specialized software to determine glide ratio (airspeed over rate of descent).



Thanks, that sounds promising. And I'm sure that as word gets out people will be adapting them for under canopy.

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I bought this thumb size anemometer around 25 years ago. Battery not replaceable but still going. As simple as possibke but was 15 or 20 bucks. Works for cheap imprecise but comparable measurement of canopy speed.

Looks like company has went up scale.:P

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

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I guess it depends on what you want it for, straight and level, swooping, etc. How accurate does it need to be and does it need to record or can you look at it in real time? But this is a simple cheap option that will ballpark numbers for you. I use one for paragliding to get surface winds, I guess hand gliders use it in flight. Seems pretty accurate in my experience, small, light, durable.

http://www.hallwindmeter.com/gliders.php

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