Is there an NPW model that resists backstalling during lulls? I have an NPW21 that works fine in steady winds but most of the time I have to continually ease the brakes and re-apply when the wind builds. I have tried changing bridal lengths and various other things with no improvement.

Ian is the resident NPW21 expert and hopefully he will chime in. I have made a few and flown them. My experience is that they need less brake tension than the NPW5 or 9. My lines looked kind of slack with NPW 21's in lighter winds. Needing to react to the change in brake tension is not uncommon for NPW's as wind changes in my experience. At some point if becomes second nature and you sort of don't know you are doing it. Generally, if the nose starts to collapse - you need more brake, if it starts to fly backwards or backstall put on a little power.

As for a non-backstalling NPW - I can't say anyone model is less prone than any other. I've made and flown NP5's, NPW9's, 21, single keels and some other oddballs and flown the Nasa Star 2. In my experience flying on a bar/duel line makes them more prone to backstalling. I assumed from your comments that you are flying with handles (quad line) though. If not, you might consider it.

Perhaps you made this kite yourself (they are not commercially available.). You might also doublecheck all the bridle lengths, esp. the brake bridles. Also when flying it - look to see if any of the bridles look very slack or too tight as compared to the rest of them.

Another issue could be your flying lines. Lines will stretch, but the power lines will stretch more than the brakes if you use nylon, dacron or polyester lines. Spectra works best for flying lines as it is less stretch resistant. Having said that - I used dacron a lot when I started making NPW's and didn't find it terribly troubling.

I've been using handles but would like to try a bar with a skateboard but because of the backstalling issues I haven't been able to. I'm using a good set of spectra lines.

What size kite is it? Did you make it? If so, what plans did you use?

It might help if you use z-bridles. Z-bridles lock in the brake and power together (allowing the kite to be flown with 2 lines) but then add another brake line which gives you the ability to apply some brake as needed to turn or to bring the kite down.

If you search z-bridles on this forum you will find instruction on how to make them and a lot more discussion. One nice thing is that once you make them flying off of two lines is pretty well set up. This set of plans shows how to make the z-bridles.


http://www.kiteplans.org/planos/nasa4/nasa.htm

You can ride both front side and toe side using handles on a longboard. You just have to twist around a bit more in toeside. I don't know about the back stall issue other than more wind or cleaner wind. What size npw?

Good idea on the z bridle Randy. I forgot about that.

I used Ian's software to make a 2.8 m NPW21. I don't see how the Z bridal would help because it doesn't allow you to release the brakes enough to stop the back stalling?

Do the Nasa Star kites have this problem?

Quote: Originally posted by bengineer

I used Ian's software to make a 2.8 m NPW21. I don't see how the Z bridal would help because it doesn't allow you to release the brakes enough to stop the back stalling? Do the Nasa Star kites have this problem?

What length of lines? What conditions are you flying in? Is there upwind obstacles creating wind shadow?

Sean says he hasn't had any problems with backstall with his Nasa Stars. I have had some backstalls with my NS2, but it was pretty minor and certainly not enough to keep me from using it with my ATB. Ian's plans are the best available, so its not clear to me why that would happen. Ian always recommends z-bridles, but yes - you would lock the brake tension in so it might not solve it. I guess we will have to wait for Ian to chime in to see if he has any ideas. I certainly wouldn't get another kite (unless you just want to) before spending the time to try to solve the one you have. NPW21 ought to work just fine for your purposes, bar or handles. Some might argue the 2.8 is too big to fly without some sort of brake or kite killer. I don't really like using a bar or dual that much so I've not spent much time thinking about it.

Quote: Originally posted by Randy

Sean says he hasn't had any problems with backstall with his Nasa Stars. I have had some backstalls with my NS2, but it was pretty minor and certainly not enough to keep me from using it with my ATB.

I would say that backstalls with NS3s (probably same with NS2s) flown off of the standard bar is a factor of wind conditions (steady versus lulls) piloting issues (keeping it moving in the correct direction at the important times) and SIZE. The really large NS3s (8.5, 10.0, and 12.5m) are more prone to backstalls and outright backwards flying. This is likely a factor of inland winds being light enough to fly these beasts also tends to be quite variable. These bigger STARS are just too much kite to keep in the air in the lulls and backstalls just sort of come with the territory. Still fun, but that sort of flight behavior just sort of seems to go with the (inland) territory.

Yeah, Steve and Randy pretty much sums it up on the stars. Also flying no line or short line can cause some back flying due to not being able to sine kite to keep flying properly. Usually more of a problem in light gust/lull wind.

Maybe the terrain is too hilly in my main flying spot which disturbs the wind. I use 25 meter lines most of the time for static flying. Flying with shorter lines is usually worse.

I'll try keeping the kite moving more to see if that helps.

Thanks for all the input.

Back stalling should be purely down to brake tension, the only other thing that may cause it is the wing tip B5/6 or if you used tension lines in the TE panels they may be a little over tensioned.
What wind speed are you flying in? A 2.8m may be just slipping down the window due to not enough wind? If it appears to backstall can you turn the kite to pick-up speed or does it just keep falling?
If you have tension lines have you increased the tension at all? If so try releasing them a bit, if there is not enough tension all that will happen is you will start to see more TE flutter and less back stalling.
Does your flying spot have obstacles? Like trees / buildings etc there maybe dead spots which you will need kite speed to get through.
For a 2.8m I'd say off the top of my head you would be looking at needing 10mph plus wind for static flying.

I have never flown a npw21 but if it is anything like the npw9 then it will need more or less brake input depending on the wind speed.

Susan (npw goddess)

For what its worth, I got rid of my Nasa 2 because of the backstall issue.
It was not the kites fault but mine. I had a mental block about flying the Nasa with a little brake.

@Susan the 21 is very much like the 9 I just find it is a lot more forgiving. Less nose collapse. That said you do have to be dialled in when flying an Npw it is more of an art and once you crack it it all becomes second nature. It's like the force Luke learn to fly an Npw and you have all the skills to fly anything.

Just wanted to check back in on this. I tried easing the trailing edge tension lines as Ian suggested and It seems to have helped very much. I only had a light wind to test in but the kite was much easier to fly and seemed to have a bigger window.
Thanks