Author: nickw

Semi-success with the ferry…

Thursday I met up with Averil at the waterfront after she had an appointment in town.  Though the wind was not ideal, we managed to fly the blue parafoil and some mixed results with the ferry and dropping things.

Tauranga Harbour and a pretty sharp southerly wind.

I had carried all the kite gear there from home on my ebike.  edbikes.co.nz  I’m making my EdBike work for its money…

The kite was biasing to the left, to the point that it would lose the air into the openings at the top – and then collapse to the ground!  So I did a bit of line trimming.  By the end of the session, it was pretty stable.

The ferry is something of a hassle to set up and work with in the wind.  But I launched it up probably a dozen times.  “Ideal” would be the ferry goes up, hits the stopper, drops whatever, and returns down the line.  I did get that a few times – but also had real issued with the trigger point on the kite getting caught up into the wire that runs through the polystyrene ball that is the stopper.  I don’t think it really needs that ball – I’m going to replace it with a piece of pool noodle.

The sail on the ferry probably could do with a bit of tail of its own.  It has a tendency to swing about, and even start wrapping around the line.  But I’d say the stopper issue above was more significant – get that fixed and all might be well…

Preparing to launch the ferry.

I had reasonable success with just sending the ferry up, letting it trip, and fall back down the line.  I did that on its own a few times to confirm that it could function well on its own.  Now just to get a better way of carrying the payload, I think.

A ‘less than successful’ attempt, with the ferry catching on the stopper, then bringing the kite down.  Second video has a more positive attempt, with the ferry rising and falling as it should…

My Picavet rig…

Since I had the blue kite line stretched across the living room to take photos of the ferry, I got out my Picavet rig for a picture, too.

It has a long history – initially developed to provide stability for the (early) camera attempts from hot air balloons, I think.  Here’s a good description of it generally:

https://publiclab.org/wiki/picavet-rigging

And here’s my rig.  It has a plastic base, and uses eye screws for the line to run through.  Better would be some smooth action pulleys.  But I gotta say – you don’t try to take photos from a kite expecting serious stability.  For me at least, it just isn’t going to happen.

But there are other people using more sophisticated systems that can do better.  I’m just happy with any photos – or even poor quality movies! – that I can take from my kites.

Sidetracked: I made a kite ferry…

Looking up the kite line. The release mechanism is at the lower left. The two strings attach to the sail – and when they are released (when the ferry gets to the stopper), the sail flaps loosely, allowing the ferry to come back down the line. Maybe too fast, but we’ll see…

I’ve put the silver flowform aside, as my initial sewing was pretty abysmal.  I think I’ve got the tension, etc, right now…

So yesterday and today I used what scraps of materials I could find to make a kite ferry…

I think about dropping things from kites (an admirable pastime!) in three categories.

  • A simple dropper. Elastic/rubber creates the tension – when you jerk on the line, the two pieces separate, allowing the ring to drop away. But then you have to pull it in again if you want to drop something else…

    A simple dropper.  The ‘payload’ is attached to the kite line and raised up into the sky.  It is dropped by some (unspecified) mechanism.  Kenny Noble and I tried to perfect a knot that could tie a plastic parachute to the kite line, and then release it with a series of tugs.  Not always successful, and really at the bottom of the hierarchy in my mind!  I’ve made one device that uses rubber bands as resistance, allowing it (sometimes) to drop the payload when it is pulled – but it is pretty fine tuning to keep it from extending and prematurely dropping.

  • Next would be a kite messenger.  In this case, the device (along with the payload) runs up the kite line on its own.  When it hits a ‘stopper’ on the line, it releases the payload.  But the messenger doesn’t have any way of coming back down the line.
  • The release area. When the front of the ferry hits the stopper, it pushed a fibreglass rod back through the main rod. And the items held by that rod drop away. And one of them holds the lines that hold the wing against the wind . And it can then slide back down the line.

    Then comes the pinnacle, in my opinion – the kite ferry.  This is a device that will climb the kite line, hit a stopper, drop its payload – but then change configuration so it can slide back down the line.  Though I’m dropping various junk, the longer term plan is to use this device to drop fishing hooks – allowing Averil to ‘cast’ her fishing line much further out than she would otherwise be able.

This is the second substantial messenger I have made.  The first was over-built, but did sometimes, periodically, occasionally work.  I’ve not persevered with it over the last year much.

Last thing to do is to work out an effective stopper – maybe a polystyrene ball?  I have had mixed results making the ‘disk’ type stopper.  They have worked, but I’m hoping for something more workable.

And my final design feature relates to my wanting to be able to break the device apart, roll it up and carry it easily.  I think this one might be a winner, eventually.

Silver flowform almost all cut out…

The kite has only 10 pieces in total.

All but the ribs have been cut now. 3 keels, front and back are done.

I’ve now created brown paper patterns for all but the front and back – those are measured directly onto the fabric.

Seam allowance around everything, though sometimes a bit rough.

Both the front and back of the kite have a range of circular air scoops/vents.  So far, I’ve cut them out with an old soldering iron.  But I want to have a go at reinforcing them with stitches.  The sewing machine is capable; am I?

Silver flowform

The blue parafoil is finished – and I’m going to strike while the iron is hot to start making another kite!  Striking with a hot iron, even just a hot soldering iron, is something you need to be careful of when working with rip stop nylon!

Flowform kites have a lot in common with parafoils, but are not nearly so ‘elegant’.  But considerably easier to sew, and since I’ll be sewing this one myself, that is a real factor.

The kite will be just under a metre wide, and a bit over 1.1 metres wide.  The lack of exactitude here is due to the fact that the pattern is done in inches, and I’m converting to metric for the layout.  Gets a bit confusing…

Here’s the article from the old Kitelines magazine that I’m using as my guideline: Flow Form Kite

I recognised the maker’s name – Ed Grauel, assisted by the magazine editor, Margaret Gregor, and figured it must be a pretty reliable pattern.  I can’t see any reference to the magazine in which it first appeared – it appears on the Internet as: http://www.kiteplans.org/planos/flowform5/flowform5.html

The blue parafoil can fly!…

Last night I made my only sewing contribution – I made a drawstring bag to carry the kite in. 

Though the wind was somewhat too mild and somewhat erratic, I can confidently say now that the blue parafoil can fly!

I wasn’t confident to let out a lot of line.  Until I get it tuned exactly, it has something of a tendency to over-correct – and sometimes go around in increasingly fast loops until it either crashes or loses its shape and flutters to the ground.

But flying.  No doubt at all that it will be a heavy puller – when I didn’t have it tied to a bench, it could feel sort of scary even at low altitudes, pulling enough to be more than I’d want to handle in a bigger wind…

I’m going to see about getting a heap of (cheap) sewing machine bobbins, and try to develop a better ‘tuning system’, a way to easily lengthen and shorted specific towing lines.  More to come!

Plans for the blue parafoil…

1982 Edition 3

This .pdf parafoil kite plan is from https://www.kiteplans.org/planos/parafoil4/parafoil4.html,  but I have used Google Translate.  As you can see, it is about 35 years old, but I liked the approach by the author.  It isn’t a plan to tell you how to make it – it just concentrates on quality calculations to create the patterns.

I didn’t use this so much as a ‘plan’ as for the shape of the aerofoil and fins.  I relied on an element of trust when it came to some of the maths…

 

Sewing is finished…

Sophia finished the last of the sewing last night – more than a half kilometer – (more than 1600 feet) of sewing.  Estimation is based on the spool of cotton (well, polyester) that was used.

Preparing to finish off trailing edge.

Then I sat on the couch are got/kept Paris the cat’s attention.  She enjoyed the bridling process immensely.

So I stretched the kite out on its back, and gently pulled the strings, trying not to disrupt the relative flatness, as the 18 fins gently lifted.  I could then, letting the strings run through my fingers, position the soon-to-be towing point above the kite.  I’m aiming for about a 22 degree ‘angle of attack’, the angle the face of the kite will be, based on the pull of the line below it.

Pulling the 18 lines up to set the towing point. May need to do this better, or at least fine tune the lengths when it flies…

That shallow angle of attack, combined with the relative ‘thinness’ of the aerofoil shape that I am using will produce, I hope, a really high performance pulling kite!

The bridling I did last night was pretty rough – I’m not expecting immediate success at stable flying.  It has a lot of fine-tuning to go before I can teach it to fly (heh, heh).

First flight might be later today…

 

Nearly finished!

We had some time off from making the blue parafoil, what with life and other commitments…

But got seriously stuck in yesterday.  We had completed the stitching to attach the 18 ‘fins’ from the face of the kite, as well as the 11 ‘aerofoils’ coming off the back of the face.

Yesterday was a lot of repetition, pinning and sewing the aerofoils to the back square of nylon.  This involves sewing a curved shape to a straight line – not massively difficult, but I reverted to pinning rather than ‘hot tacking’ the nylon with an old soldering iron.

Ready to sew the final vertical seam, with the other 9 ‘pockets’ rolled up and inside the last outside pocket.

So now ready for the last vertical seam.  In order that the rough edges of the seam will be inside the pocket, the entire kite is rolled and folded so that all of the kite is inside the final pocket.  The process is sometimes called a ‘burrito roll’ by kitemakers.

When I did my own sewing in the past on parafoil kites, I would often be a bit sloppy, and end up sewing through layers that I should not have – and then having to go back to unpick it to try again.  With Sophia’s vigilant eyes, I have been more exacting and methodical in the folding back and pinning.

I’ve already got the lines ready to attach to the 18 tow points on the fins, so after this last vertical stitch, the kite will emerge from that last pocket like unrolling a rolled up sock.  Then one last seam across the bottom to close off the trailing edge of the pockets.

First flight maybe today?  Something of a deadline, as Sophia will be leaving tomorrow…