Kite construction plan
Next week in Dieppe, some asshole realized how good kite Raaseri-H was, and stole it from my kite bag, when I was flying my ballet demo with Raaseri-M on the main arena.
I flew Raaseri-L in European Cup '94, St. Moriz, both in individual precision and in ballet. I didn't score very well, but it's not the fault of the kite! Raaseri tracks and turns very precicely, even in slow speeds and on the edge of wind window. It's also radical enough to be used in freestyle and ballet.
Raaseri prototype was flown by many rec.kiters indoors on FanÝ '94. Photo of Andrew Beattie flying Raaseri protype in tennis hall on FanÝ (Image size 50 KB) (Photo: Michael Schneider)
Raaseri prototype had Icarex P31 sail and RCF-6 frame, weighting more than 250 g, not a real indoor kite - the kite didn't know that, but flew!
Rouben Ter Minassian from France made one page plan of Tracer in 1992. He gave a new name to it: T'a Soeur, which sounds close to 'tracer'. I continued the joke and named my version to Raaseri, which is a Finnish slang word for 'racer'. When I gave the name in 1993, I didn't guess Raaseri will be my primary competition kite on the following season(s).
I suppose Raaseri has somewhat same main dimensions as Tracer (I have never took any measurements from a Tracer), but differs in:
The dimensions in Raaseri drawing (Image size 8.6 KB) are in meters and from a flat, unassembled kite, when assembled e.g. the wing span is smaller than in drawing.
|Sail||Icarex P31||Icarex P31||Icarex P38|
|Leading Edge Spars||IIIP/Res12||RCF-7||RCF-7|
|Upper Spreader||RCF-6 Strong||RCF-7||RCF-7|
|Lower Spreader||RCF-6 Ultra||RCF-7||RCF-7|
SkyShark IIIp was selected for the leading edge (LE) of Raaseri-L because it's wrapped structure takes bending stress without breaking more often than pultruded RCF-6 Ultra . Actually, I have not broke any of IIIp in ground work. Even better leading edge spar for light winds is a combination of IIIP (nose part) and Response 12 g (wing tip). Tapered Response is more flexible but the thinner end is stronger than IIIP.
However, if you have to cut SkyShark spar, you loose the re-enforced end(s). That's why RCF-6 Ultra was used for spine and lower spreaders.
RCF-6 Strong for the upper spreader in Raaseri-L was not selected for strenght reasons, but to move the center of gravity forwards. Same effect can be achieved by inserting some 4 mm carbon or glassfibre rod inside of RCF-6. Originally I had the upper spreader made of RCF-6 Ultra. When I flew Raaseri-L and walked down to gain field, it had tendency to lift it's nose. That's why I had to add some weight. The balance may vary depending on the construction details, e.g. on the weight of cross and LE connectors. If you are lucky, you may need no rebalancing.
RCF-7 is very nice spar for medium and high wind kites; it's stiff, strong and has attractive price tag. The extra weight - compared to 6 mm sticks - gives more inertia for the kite and e.g. makes Raaseri-M to axel much easier than Raaseri-L. I haven't broke any of RCF-7s in my Raaseris. The leading edge of Raaseri-M and Raaseri-H is made from one piece of 1.65 m long spar; no weakening joint in the middle! If you don't have RCF-7 available, SkyShark VIIp will also do well in Raaseri-M and Raaseri-H. Beman Ultra Light 21 is also a very good choice.
If you are not going to build the whole set of Raaseris, RCF-6 or SkyShark Vp frame will make a good all around kite for 3...8 m/s winds.
Although the drawing gives the lenght of the upper spreader, don't use it! Instead assemble the kite and find the lenght of the spreader by trying a piece of stick. You may need to adjust the lenght to find optimal tune - it's recommended to start with a longish spreader and going towards a shorter one.
Templates for the sail panels can be constructed by hand, based on measurements in either of the two identical sailplan drawings:
Sailplan in postscript format (file size 78 KB) or sailplan in GIF format (file size 14 KB)
Templates can be generated automatically by printing the file template.ps on postscript viewer/printer.
Mike Emery has converted the templates to KiteFlight/PLOT format, which supports dot-matrix and ink jet printers without postscript.
Postscript file prints multiple A4 (or legal) size sheets, which should be glued together to make 1:1 size templates. There's a 25 x 25 mm grid and page coordinates (0/0 being lower left hand corner, 1/0 right to it and 0/1 above it) to help positioning. Before cutting your fabric check that the spine lenght of your template is about 110 cm as in the drawing. Some people have got "maxi" version templates from their printer (!?). Have a look at the beginning of file template.ps, there's a line:
/mag 9.5 def
which defines the scaling of templates. If your first printing results templates e.g. with spine lenght of 131 cm instead of 110 cm, you should change the ps code to:
/mag 110 131 div 9.5 mul def
If you then want to make a 3/4 version of Raaseri, just change the ps code to:
/mag 3 4 div 110 131 div mul 9.5 mul def
Scaling does not affect to the grid size, it will stay 25 x 25 mm. In the end of template.ps file there is a comment line explaining how to select the pages, which are printed. When you adjust the scaling you may need to play with this part of the postscript if you want to avoid printing a few "empty" pages, having just the grid on them.
Templates are of 'final' size of the panels. You have to add your favourite seam allowance and fabric for the spine tunnel to the templates. "#" like symbols indicate the nonsquare grain/bias direction for Icarex P-31.
If you prefer simple solutions, forget the spine tunnel. The purpose of the spine tunnel (Image size 8 KB) is to keep sail centered and prevent the sliding in tight turns.
I sew left and right panel 1's together, making the spine tunnel, too. Then I sew left panels 2, 3 and 4 together, right 2, 3 and 4 together. Then sew the left, middle and right part together. Next the trailing edge, and then leading edges. One thing in the order is important: you have to sew all the panels together before the trailing edge , otherwise you can't get the tensioning line through!
Template dimensions expect you align the LE of the ripstop with the fold on LE re-enforcement tape. Sewing the LE is not an easy task because of the curved shape. I'll make the leading edge re-enforcement from four pieces of dacron tape or Mylar laminated Icarex PL62.
The curved part from upper to lower spreader is made from two pieces of tape like this:
Leading edge from nose to upper spreader and from lower spreader to the wing tip are made of one folded piece of tape.
When sewing the trailing edge, leave room in the fold for tensioning line. I have used a thin 2 m long piano wire, which is folded at the middle, like a sleeving tool, to pull the tensioning line inside of the trailing edge. 150 kg spectra or 75 kg polyester is suitable line material. Leave small loop at the tail and smooth out the trailing edges towards wing tips. Sew the tensioning line to the sail from tail to the standoff connection point. Leave it floating from standoff to wing tip. At the wing tip attach 3-4 cm long loop of 75 kg Dynacore with Prusik knot to the tensioning line. Prusik knot is used to adjust the tensioning. A rule of thumb is: if the trailing edge makes some noise in straight flight, tension more - if the wing tips start to vibrate, tension less. Raaseri can be tuned to fly silent, except in very tight, inside of wing tip loops, some noise might occur.
I have two sail tensioners along the spine. One loop of 3 mm bungee cord from the loop of trailing edge tensioning line at tail to the spine end cap. This is tensioned 'lightly', just to keep the lower part of the sail in shape. Above the cutout (for X-connector) an U shaped piece (Image size 8 KB) of 150 kg polyester line is sewn to the sail about 5 cm lenght. The lower part of the U, below the cutout, should be about 10 cm long and is not sewn to the sail. The upper part of the sail is tensioned by another loop of 3 mm bungee cord pulling the U towards the spine end. This construction avoids stretching the sail around the cutout.
Wing tips are tensioned along the LE by a bungee cord. TE as described in Trailing Edge .
I make the bridle using separate pieces of line for each eight bridle legs. (Image size 3 KB) Tow point end has an overhand knot, the frame end has a separate loop connected with Prusik knot . Sliding Prusik knot allows to adjust each leg independent of the others. When locked, Prusik knot takes the load without sliding. The ends with Prusik knot are connected with a lark's head around the frame and the ends with over hand knot will be tied together with a loop of same (or stronger) bridle line. 75 kg Dynacore for Raaseri-L and -M, 150 kg Dynacore for Raaseri-H. I cut 90 cm (for the haul) and 25 cm (for the loop) long pieces of line.
The shunt leg should be tuned so that in lower part of the wind range it is loose. When the wind increases and lower spreaders bend, the shunt leg should get tight and take part of the load before lower spreaders break. Bridle dimensions in the drawing are measured from an assembled kite and can be used as starting point to tune all three Raaseri versions to your taste. When you have found the tune, you can tidy the bridle lines by cutting the extra ends away.
I have Raaseri-L tuned lower (towards tail) than Raaseri-H (toward nose)!
In Raaseri-L and Raaseri-M 2 mm solid carbon rod is used for standoffs (whiskers). Standoffs are so long that they deflect about 20...30 mm from straight line in the middle. In Raaseri-H 3 mm solid carbon rod is used. The standoffs are just long enough to make the sail tight, i.e. no remarkable bending.
I was looking for a stronger mesh (gauze) than the one used e.g. in Flexifoil front, and by accident invented to recycle sun screens from my car to the vents in kite! Sun screen mesh is pretty tight and does not stretch at 'diagonal' direction. However it is porous enough to reduce the pull of the kite in high winds. Panel 3 is mesh in Raaseri-H.
Connecting mesh and ripstop needs rather wide seam. I have used 20 mm wide flat fell seam with three straight stiches and one 3-sticht zig-zag.
Raaseri is based on Tracer design. I am not a lawyer, and cannot explain what kind of rights Mike Simmons has on Tracer. I acknowledge him as Tracer designer and suggest you make Raaseris only for your private and non commercial purposes.
The copyright of the Raaseri plan (except the photographs) is by Simo Salanne, Smooth Winds. You are granted to distribute it freely, but you are not allowed to sell it or make any changes, without my permission. It means you have to distribute/publish the whole stuff or nothing.