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Slingby Kirby Kite 1:3 Jilles**
Posted: 11 Feb 2021, 02:42
by Jilles
Hi All. slowly the build on my scale 1:3 Kirby Kite has started. In this design the wing to fuselage and wing struts connections are close to scale
Each wing has three pins to the fuselage top with the wing struts keeping the wing at the correct angle. The means there are a lot of metal parts involved . The majority is 0.8mm (0.032") brass sheet. That requires a lot of cutting and drilling. To save time and increase the accuracy by a lot I investigated if I could have them Water Jet cut. Wate rJet cutting has the advantage over laser cutting that there is no heat involved that would deform the parts in the process. I found a local outlet that was prepared to do this relative small job. The cutting fee was AUS$88.00 roughly GBP45.00 in todays rates. I had to supply the material. 3 brass sheets of 10"x4"x.032" were required from K&S. The parts need to be nested with a greater distance between them than with laser cutting so a bit more waste. In my case they could only cut minimal 3mm holes. Most holes are 2.5mm and they were only pierced in the center at 1.2mm diameter. In my view this investment is worth the effort. It saves time and you get more accurate parts as well.
This does not mean you cannot make them by hand as long as you have the time and tools. The parts are left with little bridges in the nesting, see picture BRASS1. A couple of larger parts fell out anyway.
I made a start with preparing the parts for later fitting in the model.
First I drilled the pierced holes to 2.5mm. I used a piece of timber and in my drill press drilled holes to suit the various tubes sizes that need to go through these brass items.
Similar items were stacked together with the matching tube as guide
drilled the first 2.5mm hole and fitted a M2.5mm bolt, then drilled all the other 2.5mm holes
All done in the drill press so they are all plumb. see picture BRASS2.
The bottom bracket in the fuse for the wing strut connection has a doubler and tube ( say Boss) soldered to it.
Again a piece of timber was used to have two brackets lined up and the tubes square and parallel.
I used hard solder (No resin) and flux. With a little gas burner it was all heated up and soldered. see BRASS3
Separated the parts and trimmed the tubes to length. Smooth on one side, 1mm high the other side. parts cleaned of residue flux with water and a steel brush. then drilled the outer 2.5mm holes through the bracket and doubler plate. Piece of cake so to speak, see BRASS4
The little gas burner I got from my local hardware store for $8.00. It can be refilled but that cost probably more than buying a new one
There is more soldering work to do on other brass parts that will be performed in the same way.
Picture kb13 shows the original fuselage bracket to take the wing strutsat the bottom. Left and right are separate items. I decided for structural reasons to make them in one piece but kept the original shape were they are visible.
A model friend of mine Brian Ford invested in a large Laser cutter. and he is prepared to cut all the laser parts for me. This is for Brian a first to cut a large kit so a learning curve for him and I will not pushing him. Next post will be when the laser parts are in house.
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 01 Mar 2021, 04:11
by Jilles
This build is not going fast. There is a short supply of spar and stringer sections and shops will not restock until April or so. I have them now made for me and have them I hope in 2 weeks. NC cut parts are also on the waiting list
In the mean time I worked on items I could proceed on, The Skid assembly is one of them
Made a template with the correct curve . 4 layers of 1.5mm ply strips were glued together on this curved template. The sides then trimmed to the final shape. Not sure if the original had them but I decided to fit metal wear strips to the underside of the skid. Gliders in the 1950 with a timber skid had these strips and with the not so smooth field I normally fly from in mind they would not be an overkill.
It required 6x1mm aluminum strips. I could only get 25x1mm so I made a make shift router with my Dremel and cut them with a cutting wheel
Just a small cut every time. It took around 20 strokes over the strip length to cut through and went through 3 disks per strip in the process.
There are no doubt better tools to do this but I used what I have at hand and it worked. Plenty of time anyway
The strip are test fitted with small nails at the moment but I try to get small screws for final fitting
The receiver bracket for the main rubber block was hand made and fitted in place. it will be painted later. The rubber block is in my case a 3D printed parts from high strength ABS. and painted black, nobody will know it is not rubber. You can 3D print with a rubber type of material but it will not have much strength. It will take all the landing forces so it need to be strong, not to mention the occasional harder than normal landing we all have and side loads in cross wind
When not building in the workshop I am working on a design for a rather large scale glider for a local customer. more on this in the near future.
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 01 Mar 2021, 08:37
by Cliff Evans
The good thing about printing with TPU Rubber filament is that you can adjust the print fill and make the mount as herd or soft as you wish. About 75% infill makes the mount hard enough for an affective rubber mount. I use a filament called "nijaflex" for this type of job.
- TPU Rubber tail skid mount for ASK-13
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 31 Mar 2021, 10:35
by Jilles
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 04 Apr 2021, 11:11
by Dopieman1
Beautiful glider to model!
Its on my todo-list as well.
Follow with great interest!
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 11 Apr 2021, 05:51
by Jilles
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 01 May 2021, 01:19
by Jilles
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 01 May 2021, 03:01
by Jilles
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 01 May 2021, 18:53
by Bovin
Hi Jilles,
I made similar nose cones? with varnished ply on my Slingsby Gull and my present Slingsby King Kite (my building reports are on this site). Hopefully you can find some ideas in them.
If you doubt the glueiing to ABS ( I have only try & error experience with glues) maybe you can use the ABS cone as a mold to make an glass/epoxy cone.
I simply made a balsa nose cone from 20mm balsa planks? glued together cut and sanded in shape.
Vincent.
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 04 May 2021, 01:37
by Jilles
thank you for the suggestion. I stick with the ABS cone, A glassed cone would have the same issue I think..
One of my fellow club members offered me to try a special epoxy to try out
will report on this one at a later date
I still want to have a clear varnished ply surface like the original ones. There seems to have existed a red Kirby Kite with closed canopy, that is no option for me see attached picture
Cheers
Jilles
- a red painted Kirby Kite
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 04 May 2021, 05:49
by Jilles
instrument panle was 3D printed. a simple layout of the time. speed, altitude and a Cosmin Variometer
the panel was test fitted, A frame to support the panel is included in the NC parts set
A cardboard temple was cut to get the plywood planking of the wing pylon. In the end I will make it in two parts. A balsa support for this planking was added at the top, contour to be trimmed later to match the underside of the wing.
The first 5 plywood strips are fitted to the top nose ares . The completes the RH side.
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 05 May 2021, 13:17
by SedB
The Kite looks stunning (especially the dash)!! You make it all look so easy to do; when I imagine myself sanding the nose to shape, I can only think about sanding to deep and have to start all over..
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 07 May 2021, 01:11
by Jilles
The Dash is 3D printed by my Son. It has a back plate printed in black and a front plate printed in a different color and was spray painted green
The instrument faces were found on the internet and printed on Photo paper at the correct scale size. The Cosmin vario is included in the back plate.
I had recessed arrows included and painted them red and green. In general I do not care to much about the cockpit internals. You will not see it when it flies. A pilot is more important
Sanding the 0.4mm ply on the nose has to be done very lightly. But if you look at pictures of the original you will see that little imperfections would be to scale.
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 12 May 2021, 10:46
by Jilles
The last progress report for a while, we travelling to new Zealand for 3 weeks or so unless the travel bubble with NZ is closed before Saturday
The top of the fuse is now fully planked with 0.6mm plywood. The fuse can now be turned over to fit the lower planking.
Some supports will be required to keep things straight and level.
- lh front view
- nose strip planking as per original
- wing pilon
- lh rear view
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 30 Jun 2021, 03:00
by Jilles
Back from New Zealand and we are in lockdown because there are 6 cases in Brisbane.
Started on the Kirby again. the fuselage at the cockpit area has a compound surface. A timber block was made with roughly the fuselage contour
The ply sections are wetted on both sides and clamped to the block overnight. The result is a curved ply section that requires minimal clamping forces and the ply does not pop up where clamping is not possible. The PVA iron on methode is not adviced on these compoud curved ply items
As per original I did add diagonal bracing between the wider former spacings . this prevent popping of the ply under stress.
A bit time consuming but worth the trouble.
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 03 Jul 2021, 06:53
by Jilles
one side fully planked one more side to go
a bit time consuming but for me worth the result.
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 03 Jul 2021, 10:58
by Jolly Roger
What an interesting method to pre-form a compound panel. I can see they would hold their shape over time with the help of those additional crossmembers you've added. Thanks for sharing.
I'm attaching some photos I took of a part-restored Kite that turned up at our local gliding club in 2014. I hope they help.
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 03 Jul 2021, 10:58
by Jolly Roger
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 03 Jul 2021, 10:59
by Jolly Roger
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 03 Jul 2021, 11:01
by Jolly Roger
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 03 Jul 2021, 11:02
by Jolly Roger
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 03 Jul 2021, 11:03
by Jolly Roger
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 03 Jul 2021, 11:04
by Jolly Roger
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 03 Jul 2021, 11:23
by Jilles
Thankyou for sharing the pictures
does somebody know how many Kirby Kites were built by Slingsby
Cheers
Jilles
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 03 Jul 2021, 12:40
by Jolly Roger
25 produced according to
Slingsby Sailplanes by Martin Simons, with production ceasing in 1939 (when they cost £159! each).
There was a Type 23 Kite variant made after the war. Its wing was mounted higher on a streamlined pylon, and it had spoilers as standard plus a mainwheel. I've only found two photos of it, one in the Simons book and one copied from a photo borrowed from vintage sailplane enthusiast Ted Hull. The sole Type 23 went to the USA then disappeared.
I'm feeling like a proper vintage sailplane nerd here.
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 03 Jul 2021, 23:04
by Jolly Roger
... and I've got the BGA numbers for all 25 Kites from the Normal Ellison book if that helps anyone.
That's me - I'm all anoraked out.
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 03 Jul 2021, 23:07
by Jolly Roger
One more thing Jilles: I see your diagonal strip method is also used on the full-size.
Re: Slingby Kirby Kite 1:3 Jilles
Posted: 04 Jul 2021, 05:07
by Jilles
got the diagonal idea from attache picture.
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 02 Aug 2021, 08:01
by Jilles
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 07 Oct 2021, 06:07
by Jilles
Today the first wing was mated with the fuselage. I had a jig made up to set the metal brackets on the wing and fuse at the correct spacing and the three pins to be inline. Today was the first time to check this out. It went together as it should so no problems here.
The other wing is next, then everything needs to be setup properly to determine the wing struts pin centres
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 13 Oct 2021, 01:27
by Jilles
Tail struts are fabricated more or less as I showed on the drawing, A M3 nut was added just for scale reasons. This is used on the full scale to adjust the length to the correct pin centers. The clips shown on the pictures are just temporary. It was what I had available to test fit for now.
Also shown the trim bar on top of the horzontal stab, This is a scale feature. I presume this was adjusted by adding or removing weight bars subject to pilot weight to get the correct trim
In this model case it is built of a aluminium strip and 3 mm plywood to keep it as light as possible to reduce nose weight. It will be painted red.
Pictures of the full scale items included
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 13 Oct 2021, 08:15
by Jilles
Everything setup together for the first time. Lined up wings as they should be and measured the required wing strut pin centers.
Both are 712mm, drawing specified 713 mm so all good I would say.
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 13 Oct 2021, 08:37
by Peter Balcombe
Looks good Jilles.
Not bad for a beginner
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 07 Nov 2021, 02:45
by Jilles
Getting close to the end of the construction fase. The wing struts are shaped and test fitted. The center cover plate between the two wings is completed. As per original it slides through a slot created in the wing root ends and the 3D printed Head cushion is included.
I got myself a 1:3 scale Pilot from Great Planes part GPMQ9105 . For the open cockpit operation this has a suitable head gear. The Pilot required some shoulder surgery to make it fit inside the canopy opening.
Before fitting the fabric the surface will get a wood stain treatment to make the play surface a little darker. then a layer of spray-on clear Varnish
Then the Fabric will be fitted to the open area's. I did order 8m Diacov fabric from Sarik Hobbies and it took only 7 days to arrive at my address in Australia. good service. The Diacov looks great and will suit this type of vintage model very well. I expect a good result. The final surface treatment will be an other spray-on layer of clear varnish
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 07 Nov 2021, 08:45
by Cliff Evans
Looks great Jilles.
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 29 Nov 2021, 09:12
by Jilles
The Kirby kite is ready for covering. The ply surfaces were stained with a woodstain of Western Cedar color. then a light coat of clear varnish was sprayed on.The covering material will be Diacov what I got from Sarik hobby. A first for me but a test bit gave me good results so I am confident that this Diacov will give the required semi tranparent looks.
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 29 Nov 2021, 09:56
by Cliff Evans
Stunning Jilles!
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 30 Nov 2021, 20:43
by BrianF
Looks fantastic Jilles, looking forward to seeing it fly, maybe even tow it.
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 01 Dec 2021, 03:45
by Jilles
The tail bits are now covered with Diacov. it was the first time I used Diacov and I have to say it is a very good fabric type covering material
For those that do not know this fabric the following . It is easy to apply with the an iron. I used the iron to tighten the fabtic as well. I have bad expereinces with a heat gun like burning holes in the film.
With Diacov no need to use heat sensitive glue and/or dope. Thumbs up for the product, the price is very competitive compared to other simmilar options. The transport cost to Australia from the UK is a bit steep but not an issue it you buy 16 meter like I did . An other advantage is that you can order continuous lenght up to 10 meter.
Attache pictures show the result of today.
Also made up a wire harness for the power supply. A 3S-2200 lipo will be used with a voltage regulator to 6V. The power switch is fitted to the instrument panel
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 12 Dec 2021, 02:13
by Jilles
The kirby Kite had its first outing yesterday during our monthly Tow day. It was not ready to fly . I did a test rigging on the field just to see if extra tools were required and took some pictures. need to apply the last layer of Varnish, install the radio gear and ballast to get the C.O.G where it should be.
at the moment I expect the flying weight to be close to 8 kg (17lbs for the old guys)
Transport frames were fabricated for in the back of my little truck, or Ute as they call them here in Australia. I can carry my Ka6E and Ka8 at the same time, that is plenty for a tow day
It should fly at our next Tow event. That could be January but because it is high summer here and holiday time with many people away, we may skip the January event and go for February
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 12 Dec 2021, 08:50
by Dopieman1
Jilles, it has become an absolute beauty!!
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 12 Dec 2021, 09:19
by Cliff Evans
Well, if she fly's as good as she looks!!
Well done, again Jilles.
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 01 Jan 2022, 07:12
by Jilles
The Kirby kite Is now ready to fly. It was balanced and required 1.1kg nose ballast, Overall flying weight is 7.8 kg
Just about right of the size of maybe a bit on the low side. The plan is to maiden the model on the 8th of January subject to a heavy model inspection and weather. At the moment a cycloon is passing the coast of Queensland that may dump lots of rain. The field maybe to wet or the access road flooded.
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 01 Jan 2022, 07:27
by Cliff Evans
Very nice Jilles. She certainly looks the part.
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 04 Jan 2022, 13:22
by SedB
Gorgeous, I love it!!!
Hope she'll fly as good as she looks! I really like the finish of the glider!!
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 09 Jan 2022, 23:48
by Jilles
first proof of maiden flight, no sweat more to come later
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 10 Jan 2022, 11:01
by BrianF
I was there and saw it fly, well I towed it, the Kite looked great in the air. Flew at a nice scale speed.
Should be very happy with that Jilles.
Re: Slingby Kirby Kite 1:3 Jilles**
Posted: 10 Jan 2022, 11:36
by B Sharp
Nice model Jilles, it looks good on the tow as well.
Brian.