Building the wing
The wing is build in two seperate halves first.
This description is based on one wing half, you will need to repeat the steps for the other wing. Take care you build a left and right wing !!
Please notice: the balsa ribs are fragile, take care and apply only small force. If a rib does break, use CA
Collect the wing-ribs from the sheet of 2mm balsa sort them on size
collect the spars, you will need:
Prepare the spars:
You will need a complete flat building area of at least 100x40cm. It is usefull
to have two or more flat and heavy strips of metal or wood. I use 20x20x3 x
1000mm brass and some lipo packs as weight.
Take the main spar, and carefully slide the ribs into the slots. No glue is required yet. take care that the top of the wing is flush with the top of the spar. If this does not align you might need to file the corners of the slots a little more.
Take notice that the root-rib has a recessed area at the leading edge. The recces should point to the center of the wing.
The root and tip rib might need a push-pin to hold them in place
Place the main spar on the building surface and weight down the ribs and spar so the building tabs are all on the building board.
Locate the leading-edge balsa spar, put a small amount of white glue in the slots and carefully place the leading-edge on the front of the ribs. Take care the top of the spar aligns with the top of the rib.
place some more weight on the wing and let dry.
take one of the tappered spars, test fit the spar in the top of the ribs. For a good fit, it helps to sand the edges of the spar a little round. If the spar fits flush with the top of the main-spar, remove it. place a drop of glue on each rib place glue on one of the long edges of the tappered spar (the side that will get in contact with the main-spar) place the spar in it's slot and use some clamps to press the tappered spar against the main-spar and let dry.
time to place the trailing edge. The trailing edge needs to be placed in the small and fragile slots on the rear of the ribs. There are two steps that makes this a bit more easy: 1) sand the the front of the leading-edge (the side where the little holes are) a little tappered or round. 2) test fit the trailing edge first on each individual rib. this will clear possible left over material from the CNC cutting.
slide the trailing edge into these small slots. (yes I know this is not
|Put a small drop of CA into each corner of the main-spar and each rib. Only on the front of the main-spar.|
|time to place the trailing edge. The trailing edge needs to be placed in the small and fragile slots on the rear of the ribs.|
|There are two steps that makes this a bit more easy:|
|1) sand the the front of the leading-edge (the side where the little holes are) a little tappered or round.|
|2) test fit the trailing edge first on each individual rib. this will clear possible left over material from the CNC cutting.|
|Sand the frontside of the trailing edge slightly tappered or round. This will help to slide the trailing edge in the small slots at the rear of the ribs.|
|When the trailing edge is in place, allign the ribs with the holes. Then put a little drop of CA on each rib.|
|take one tappered spar, this will go on top. Testfit the spar in the slots.|
|put some white glue on the rib-area where the spar will be placed|
|put white-glue on one edge of the spar and place the spar in it's slot. Wipe away any access glue.|
|Use some clamps to press the tappered spar against the main-spar. |
Turn over the wing (up-side-down)
repeat the steps for the tappered spar, but now for the bottom.
Locate the balsa aileron spar. Test fit the spar by gently wiggling this one in the wing ribs. If the spar fits in all ribs, remove the spar, put some whit glue on each rib and place back the spar.
|Use a sanding block and sand the leading edge flush with the ribs. Take care not to damage the ribs.|
|Draw a line in the middle of the spar (about 5mm measured from the front of the mainspar), this line will be the rear of the front balsa sheet. From one sheet of balsa cut a part, 81cm long, 70mm on one side, 42 mm on the other side. |
|Use white glue on the spar, the ribs and the leading edge and press the front wing sheeting against the centre line and weight down. Use pins to bend the sheet to match the leading edge. Remove access glue from the main-spar area as this will cause trouble for the rear sheeting.|
|Use a new sheet of 1.5mm balsa together with the remaining balsa from the front wing cover. Create a piece of balsa large enough to cover the rear of the wing. Then use white glue on all the contact area's and place the rear wing sheeting with weights and/or pins and let the wing dry on the building board.|
Work on the bottom of the wing
|Important: there a several things that needs to be done before the bottom sheting can be glued|
Up to the moment that the bottom sheetings is placed the wing can warp. So take care to keep the wing flat.
In the picture I drilled the hole one rib to far to the tip. The hole should be one rib more to the root-rib
Time to glue to nose-sheeting. When this is glued and dry, the wing will get most of it's warp-resistence.
Make sure the support-spar is in place, weight down the rear of the wing. Then glue the nose-sheeting in place using weights and pins
Make sure you keep the support spar in place.
I used two layers of 2mm balsa scrap
Next step, cut out the ailerons
Now draw a 90degrees line to the trailing edge, starting in the corner with the hole. And repeat at the tip, about 1 cm from 3 ply tip-rib. Then draw the same lines but 3 mm to the inside
The line parallel to the aileron spar should now be 6mm
Then use a scroll-saw to cut the ribs
See also a couple of pictures further on.
Glue a wide strip of 3mm balsa to the hinge-line, take care you do not warp or bend the aileron
|Next step: Joining the wings|