Scale Soaring UK

Got to see the finished uncovered fuselage last night, very nicely built. Looking forward to seeing it covered Jilles.

The L.H. wing is well underway a support for the TE was setup. ribs in place and top spar fitted. Between the main ribs in the D-box is just foam for the 1.5mm balsa planking support. This works form better than half ribs. Foam blocks are cut into shape with a foam cutter with the ribs as guide. Weight is not an issue compared to balsa half ribs
The TE cross section is a sandwich or 1.5mm balsa at the bottom. a chamfer 10 mm at the rear edge. a 10x0.5mm carbon strip at the rear edge, an ex 3mm balsa core and 1.5mm balsa top..Cost a bit of time but compared to the total build time not an issue
In my view it has the following advantages, the TE stay straight, it is stiff and dent proof.
pictures and TE cross section attached

it has been a while but the l.h wing is now complete. After fitting the top balsa planking the wing was removed from the board and building tabs cut of from the bottom. In the NC laser kit are 9 mm balsa supports to supports the wing upside down on the building board. These are shaped to the wing top surface with 1.5mm balsa planking included There are 5 in total and they are numbered to the rib position they need to be located. These supports help to keep the wing straight when fitting the bottom balsa planking. Some weights are placed on top of the wing to keep the wing in place, These supports add a bit to the cost of the NC kit but saves a lot of time in setting up
3D printed tips sections are used. the rear edge is twisted upwards to make thing to scale.
Next is the Rh wing I will not bother you with a story on that one. All the same, just have to make sure I do built a RH wing. I heard a story that some modeler built two LH wings by mistake.
I will continue the thread when the second wing is complete. it will take a while.

Jiles, lovely glider but I do wonder why you foam fill the D box between the ribs ? The rippling between the nose riblets and the ribs is a feature on the full-size. The rippling on my quarter scale Charlesworth K8 0.4mm wing skins looks scale to me. Regards John.

John Vella wrote: ↑20 Jul 2020, 09:17 Jiles, lovely glider but I do wonder why you foam fill the D box between the ribs ? The rippling between the nose riblets and the ribs is a feature on the full-size. The rippling on my quarter scale Charlesworth K8 0.4mm wing skins looks scale to me. Regards John.

Mainly to stop you putting your fingers through!!

On that subject be very careful who you have launching (handling) your glider. Regards John.

Nothing to do with that John! Just putting it together!

Cliff is right on the money. Because the planking is 1.5mm balsa and the distance between ribs to scale (wide) the foam is to prevent damage by pushing fingers through and by transport. The foam is not fitted over the full length. From root to start of aileron and the last three rib bays near the tip. The balsa is not glued to the foam, only to the ribs, the foam is only for support when pressure is applied from outside. You will still see the ribs when painted.
The rippling effect is a feature of the full size but only when they get older. Schleicher made high quality gliders with a nice near perfect finish.
Over the years the rippling effect appears due to handling and varying stresses during flying.

Jilles, now that makes it clear that the foam is just for support and not bonded to the skin, clever idea. I have done many hours in the K8 and have great regard for the glider. Regards John.

Just something to keep you up to date. The last wing is nearly completed than the construction of major parts is done. I made a plug to vacuum the canopy. As mentioned earlier I do built the K8 with the smaller canopy that was later replaced with a full canopy with the K8B. Reason was that most model around have the larger canopy so it is a kind of novelty. Also the smaller will fit my vacuum forming machine. I started the plug with some 5mm craft wood formers as a guide, Filled the spaces in between with pine blocks and started shaping the thing. When happy with the result a layer of 80gr/m2 glass with epoxy resin was added, and after that on other layer of epoxy resin. This was sanded smooth with 240 grid wet sand paper. an other layer of epoxy resin was applied and then final sanded with 240-800-1200 grid sand paper and lots of water. Got it very smooth.
In the coming days I will try to form a canopy or two. I do use 1mm clear PETG, Vivac is the brand name. It is only available in 2.4x1.2m sheets at $50 Australian. Got already lots of interest to buy parts of left overs from me.