Hello All,

I am new member to the forum though I've been reading it for a few months now. I've read a lot of anecdotal reports of peoples preferences about kites and see that there are many general rules governing the characteristics of a kite. I was wondering if anyone has tried systematically testing kites at different wind speeds for things like window size, force, turning radius, chance of collapse or overflight?

It seems that this would be very valuable information but could be tricky to obtain because of many possible variables like pilot skill, air pressure, wind velocity and variability (gustiness).

Has anyone attempted anything like this?

Welcome!

And ... har har har! We've had this discussion before ... I want a big ol' wind tunnel with a strain gauge attached to the chicken loop and a robot flying the same pattern over and over with different kites, logging the data. It ain't going to happen.

There was one study of regular versus deluxe material Flysurfers though ...

I swear a few years back I saw someone in this huge specialized wind tunnel testing a kite......Flysurfer maybe? Maybe it wasn't a kite? Can't for the life of me think what else it mighta been......pretty sure it was a kite........

Thanks for the replies.
Tis a nifty video.... wonder what their thesis was...

Looks like this wind tunnel test is good for determining kite shape at a static angle of attack and how the wind flows over the kite which might be useful to kite makers. However, I can't see a practical application for kite users. We need a super big spring scale for measure force attached to a chicken loop synchronized to a wind gauge and a video camera capturing the position of the kite in window. Santa please?

Hard to focus on testing when you just want to ride.:roll:

You could spend years testing a given kite, with a given design, in the huge variety of enviromental conditions. Wind velocity, gust velocity (and frequency), air temp, humidity (or in my case lack there of) are all obvious factors.

I think the windtunnel offers an easy way to visually check airflow and for setting a baseline before you use it confirm the airflow, profile and all that sort of stuff.

But is no substitute for actually going out and riding it.

If you wonder what drives the cost of a kite I bet that windtunnel video is probably a good example.

I think it would be a lot more involved than a wind gauge/loadsensor/camera type set up. Wind isn't very consistent. The kite might hit a pocket of air blowing at one speed and 10feet over hit a pock at a different speed then another in another 10 feet. None of which (unless it's a huge windspeed difference) will show up much on a camera. Unless you have a camera on the kite observing skin deformation among other things. But the camera itself could alter the kite's characteristics and your results. Then it's almost a Schrodinger's cat sort of deal.

I'm assuming this is all outside. If inside the cost of that kind of windtunnel time would probably make it all prohibitive.

Then you have to deal with variables like line quality, bridal strength, panel stitch strength. More often than not construction is pretty consistent for general purpose flying but for acurate testing? No so sure.

And I think once you introduce pilot skill to the equation it all goes out the window. That's the biggest variable on your list.

I just want to ride them. Let the engineers design them and tell you what the kite can or can't do and see if you can push it a little further than they though possible. I guess I'm not as interested in the numbers as much as I am about how the kite rides and feels.

greetings,

a lot of what you ask to test is pilot input control variables ...

basic material limitations, surface reactive tolerances and design... data will help those areas. really most data collected is valueless, except to design.


pilot experience! there is NO substitute.

yeah, any one of the variables can change and make the data useless. Even if you got good data, you couldn't much use it in the field because those variables would be changing. Feeling the conditions and the ability to do so is much more valuable and rewarding. Back to back testing builds your mental database.

That's the idea - kite actually set up to fly, wind tunnel to constant 10 knots, fly a set pattern, record the results, repeat at 15 knots etc. Just to get a real-world baseline, rather like power/torque curve manufacturers release for vehicles.

Kite in the wind tunnel without actually flying it won't tell you enough IMHO :D

Y'all should be old enough to remember indoor windsurfer racing ... should be enough space to swing a kite around in there ...

I'm thinking of nice simple test.... combining all the mentioned factors including kite acceleration seems too complicated to me....

How about up wind range... that should be easy enough to test with just a video camera and some marked off pylons. Mix up the tests with different days and different wind speeds and I should hope that we would see different result form different kites.

Percent chance of collapse would also be pretty straight forward. Run to kite at the zenith/ edges of the window and keep track of complete collapse/bow tie/tip flipping/what ever compared to a deceleration. By flying the kite straight at the edges pilot skill could be eliminated.

These would be perhaps inexact, but they would be a starting point to directly comparing kites scientifically.

Power seems to be the most intimidating problem...

here you go, i have easily flown for 100s of hours with out incidence of collaspe/flipping?/bowtie (its been years) .

kite acceleration is an input element for it to happen. the piolt is what smoothes out the wind luff and kite behavior.

if the wind is smooth , it can stay up all night and day with out the pilot! esp. ARCS!

minimal threshold wind for absolute stability/time WITHOUT pilot input would actually provide useful info. and that would have to be across kite types and brands. this would provide confidence for novice flier to start with the right conditions so the rig can fly well without much pilot input. early threshold would keep the power intimidation to the lowest point for newer pilots. this would have application.

thats what most want... use without fear. unfortunately a human element that no number will ever quell.

It looks like they were studying the airfoil.

I didn't fly 100 minutes without incident today. :wee:

I hope the incident wasn't painful to you or your kite.

Ha, no kite's fine and I have all my fingers and toes. Hope to post vid of the day shortly. :wink2:

ouch!

These are videos from a paraglider certification flight.

http://vimeo.com/7535001

http://vimeo.com/7534817

http://vimeo.com/7534631

(Unlike Rip, Alain Zoller was impressed enough with his certification flights for a Sky Country product that he bought one for his personal flying.)