Power Kite Forum - Learning NPW on two lines- dumb?

Learning NPW on two lines- dumb?

mbseto - 13-5-2015 at 08:54 AM

Hey all, got a newbie question...
I made a Teega style NPW, 1.3m, and trying to improve my flying. Right now I'm not surfing, buggying, etc., just standing in a field or on the beach (is this called static?) and trying to get better at just flying.
I have it rigged with two lines, and once in a while if conditions are just right, it flies really well. But most of the time, it is extremely finicky. It takes a lot of focus to keep it in the air, and then if the wind is not right for just a few seconds, the top often folds down. Sometimes it will reinflate, but I always know if the top folds down more than halfway, it's going down. I'm lucky to be in the air more than 30 seconds at a time.
So my question is this: Is the lack of separate brake lines actually making it harder to fly? My initial assumption was that two lines would be simpler, and once I got good at this I would graduate to 4 lines. Now I'm wondering if this was a mistake...
Thanks...

bobalooie57 - 13-5-2015 at 09:19 AM

I've never flown the teega style, but I am pretty familiar with the NPW 5 and 9. I have flown those styles both as 2 line and 4 line, and feel you would definitely benefit by adding brake lines to your set up. You will gain so much fine control, you will hardly believe it. I have read that the teega, even flying 4 line can be quite twitchy, but with brake input you will be able to correct the folding, nose collapse, etc. just by tweaking one brake or the other. Also relaunching, though not too bad with the NPW on 2 lines, is much easier with the brake input available flying 4 line.

Randy - 13-5-2015 at 09:40 AM

Wow - I'm impressed you started with a Teega, which appears to be one of the most difficult NPW's to build and maybe one of the more challenging to fly. I've flown a lot of different style NPW's (but not a Teega) on both 2 and four line. It is a bit surprising, but the NPW's all fly a bit differently. In general they need brake tension to fly well.

The braking is fairly critical in terms of getting a NPW to fly well on two lines. If it flies backwards or upside down, you have too much brake. If the nose collapses a lot, you have too little. What I try to do is get it just past the point where it has too much brake. Just based on your description it sounds as though you may need more brake - so you would move the connection point up the line (closer to the kite) a bit. I usually put a number of knots on the brake lines maybe 1 cm apart and then pick the one that flies the best. You might also double check your brake bridle lengths to make sure they are all correct.

I have found a lot of times if an NPW kite is not flying well on two lines, switching to four will solve the problem quickly. They generally fly best on 4 because you can fine tune the brakes by watching the kite fly and react accordingly.

Have you flown two or 4 line kites before? It may just take more practice if so. Also, the wind and location (turbulence created by objects in the area) may be a problem as well.

There are some videos available on you tube showing how to fly a quad kite. You might look for those. Most conventional quad line kites require some slack in the brake line, so keep in mind the NPW is different - it wants some brake pressure.

Perhaps Ian (bigE123) will weigh in with explanation of how to make a z-bridle which would facilitate flying on 4 lines with conventional braking technique. A bit complicated, but far less than building a Teega in the first place.

bigE123 - 13-5-2015 at 12:44 PM

Firstly welcome mbseto to the Dark side of the NPW builders :D

Firstly a couple of questions:
1: Did you just tie the brake bridle lines to the main collection point?
2: From memory the Teega has tension lines in the wings and centre panel, have you set them to the tension stated in the plans?

Whenever I build an NPW I bridle in four line mode to start with, hold your handles with the top finger under the top power line, this allows you to fly holding some brake line tension. In four line mode you will see the effect brake line tension has, by tipping the handles forward ( the bottom getting closer to you, the kite will back-stall, tipping them the other way (top getting closer to you) the kite will start to show a nose collapse. Four line is a really good way to learn how the NPW flies and how your input changes the kite, plus you can do brake turns which will make the kite virtually turn on it's axis.

Once you are comfortable on four lines, it's great for static flying as you can really hone your skills. Do a search on here for Z-bridle, I did a post on just that. In essence what it does is connect the brake bridles to both the power side and brake line meaning when you release the brakes at the handle the Z-bridle holds the brake bridle tension preventing the nose collapse, it the means you hold the handles with the power line between your top two fingers as the only time you need to use the brakes now is for tighter turns and landing.

With learning how to fly 4 line when you put the Z-bridle on you will be able to determine if it needs a bit more or less brake to get the "sweet spot" it's only a matter of @5mm between a nose collapse and that sweet spot, so just do small changes util you hit it.

The reason I mentioned the tension lines is that if you put too much tension on then that will cause back stalling, too little tension and you will get wing flutter, the tension is something that should really be done in four line mode. You will notice the more centre panel tension the less brake line tension you need but the kite will slow down and ultimately when you go too far back stall and not take-off.

When doing any tuning just do one thing at a time, if the wings flutter just do one side the you can see the difference, once it's right on one side do the other by the same amount, then do the centre. When it's all flying sweet..... Z-bridle it :thumbup:

We're always just a post away, no matter what the question just post it, you won't be humiliated as we're all here to learn and share.

mbseto - 13-5-2015 at 01:10 PM

First, thanks everyone for all the information. Sounds like the consensus is to take the leap for 4-line. To answer some of the questions:
-This is my first multi-line kite.
-I picked the Teega because it seemed like the most "developed" NPW design. After lurking here for awhile, it looks like that's a debatable point.
-I did tie the brake line to the main collection point. I did a massive amount of tuning, both on the regular harness lines and the brake lines- probably tied and retied at least a hundred knots.
-I set the tension lines to the length stated in the plans, but after flying I ended up making some adjustments to get everything even.

I remember seeing some info on the Z-bridle and filed it away for future reference. I remember it looked like a really clever mod. I'll dig in to that again, and work on fabricating some handles.

"Dark side of the NPW builders :D" You're not kidding... I'm dying to build a 3m NPW9 now. I really need to get a handle on this little guy first, though.

Let me see if I can attach a pic of the culprit...

kitemaker4 - 13-5-2015 at 07:41 PM

I made several teegas about 5 years ago. I found them to be very twitchy kite and have stayed away from them since. Fly them as a 4 line kite and you will have lots more control. You need to be able to have brake input on them. You will find that the npw9 flies a lot better.

Susan (npw goddess)

bigE123 - 14-5-2015 at 01:42 AM

Nice first build!

I think one thing you will find is that if a kite is "twitchy" by it's design then a small one will be even worse, I find that most models get more stable the bigger they are, and obviously with a small build you need to make sure that all the measurements are absolutely bang on.
I haven't built a Teega but have used some of the techniques/ideas from that build, the NPW5en / 9b / 21 are all good kites but do really need to start life as a 4-line to get them set-up. With bridles it's all about being consistent, now I only measure the longest bridle in a set, eg if A1 is 200cm I measure and cut that, if A2 is 190cm I use A1 and cut A2 10cm shorter, just a personal thing that I find gives me better consistency. Like most things there are lot's of different methods that each person will swear by, it's just a matter of finding what best suits you.

The one NPW to avoid or do as a tongue-in-cheek build is the 9b-HA it flies like a stunt kite but is abysmal for traction as the window is smaller and tends to reverse fly.

mbseto - 14-5-2015 at 12:08 PM

"Nice first build!"

Thank you! When conditions are right, it is a blast to fly. And Susan, I think read your opinion on Teegas somewhere in the forum, but I had already cut cloth at that point.

Well, I will embark on setting this up as a 4-line. Just one follow-up... Would it be fair to say that using a 2-lines basically sets the kite up for one particular wind speed, whereas 4 lines allows you to fly in a broad range of wind speeds?

bigE123 - 15-5-2015 at 12:26 AM

Quote:

Would it be fair to say that using a 2-lines basically sets the kite up for one particular wind speed, whereas 4 lines allows you to fly in a broad range of wind speeds?

In essence yes, imho especially connecting to the main collection point, the brake angle changes, which is why a Z-bridle works better, even with a the Z-bridle you may at times just need to dab the brakes if you see a slight collapse starting. Like I said before on a smaller kite the margins are much smaller so getting the two line only will take some doing, give four line ago and it will give you a real insight in to how much control is needed from the brakes.

You won't get a huge wind range with a 1m kite it will probably struggle in wind under 10mph, just out of interest what wind speed are you flying it in?

Randy - 15-5-2015 at 05:17 AM

Ian,

I'm a little surprised by your comment. My small (~1m) NPW's fly in very little wind - certainly less than 10 mph. I could agree though it you meant 10kph. They will consistently fly in less wind than commercially made foils. Even my first tarp and tape 1m NPW 5 flew in ~7 mph. It was hardly a masterpiece of construction. I'm not sure what the upper wind ranges are, but i think I've flown a lot of them ~20-30. Sean and I used my 1 m SK for landboarding in a ton of wind.

I've thought about the tolerance issue. Make a 1 cm mistake on a 100 cm measurement - its a 1% error. Make it on a 200 cm measurement - its only 1/2%. I started making small NPW's because I couldn't sew a straight seam of any substantial length (and made most of them not following the actual fabric layouts in the plans, but rather made them to minimize the number of seams.:D) The 1.25 M NPW 21 was one of the few that pretty much went according to Hoyle. My early single keel's also followed JC's plan layouts, though I later discovered that it is easier (and more fabric efficient) to just sew two NPW 5 wings together.

Some things do seem easier as the size gets bigger, such as making darts, or in fact the entire nose.

I thought about making a Teega to complete my NPW airforce, but Susan's comments seemed pretty compelling, and the plans themselves talk about the fine tolerances required, so that scared me off as well.

bigE123 - 15-5-2015 at 06:41 AM

:D you have me there Randy, the smallest NPW I've made is 3m so was trying to guesstimate what a 1m would need to be powered up without issues.

Yep you hit the nail on the head about what I said regarding the tolerances, the bigger you go a few mm to a cm get lost rather than being an issue. Sewing wise the bigger the build it's then a matter of dealing with more material through the machine. With regards to the material layout, if you go single colour you mark two wing halves, then flip the material over and mark the other two, you will then have two wings that match material wise, this is only an issue if there is a slight difference from one side of the material to the other, some has a slightly duller side than the other.

kitemaker4 - 15-5-2015 at 07:17 AM

Quote: Originally posted by mbseto

"Nice first build!"

Well, I will embark on setting this up as a 4-line. Just one follow-up... Would it be fair to say that using a 2-lines basically sets the kite up for one particular wind speed, whereas 4 lines allows you to fly in a broad range of wind speeds?

With the kite set up to fly on two lines the brakes are fixed on the kite in flight. The kite set up as a 4 line kite you can adjust the brake tension with the handles and get more out of the kite in different wind speeds.

Susan (npw goddess)