Here are the pms sent by shobit sir to me...
sharing this in public interest...
pm no. 1Dear Friend,
Well all you need is to take a wood block of maybe 3 inches width and about 12 inches long. Say .5 in thick. Make three such Blocks. DO NOT use plywood or ply board as it will hurt your hand and fingers with the sharp edges of wood which are there.
Now stick sand paper of 120, 100 and 60 grit to these blocks of wood. Use the sandpaper which comes on cloth strips of about 4 inch width.
Now cut your sheets of thermocol of the required size. Make sure the wing sides have come out exactly same in size.
Now make the max camber line on both top and bottom surfaces. If its a flat bottom one then it is needed only on the upper surface.
Next make place for the Training edge and the Leading edge on the thermocol for the wing. I use a 10 mm sheet balsa for the LE and a 6mm sheet balsa for the TE. generally the sizes are 10 x 10 mm and 6 x 20 mm for the TE.
Sand the TE as required in a wedge form. Fix the LE to the place on the foam.
Now sand the entire wing by keeping the thermocol on a table taking care to leave the place thich enough for you to fix the TE and also make sure that you shape the LE as you sand the wing using a 60 grit sand paper. DO not file to the exact size with this paper as it is very rough and tends to breast the thermocol at times.
Use 100 and 120 grit paper to smoothen the wing surfaces......
After smoothening the wings add the TE to its place.
Now use a knife and cut grooves for the spars. I have used hard wood spars and also used balsa spars. Make the grooves on the top and bottom surfaces and put spars on both top and bottom surfaces.
For making the wing dehideral use a a 6 mm plywood piece or a 6 mm hard wood beeding as the centerpiece. make use it is right through the thickness of the wing thermocol and is at least 6 inches outwards from the centre into each wing.
Now once all this is done. I cover the centre section with a glass fibre cloth and epoxy.... about one foot of the centre section on top and bottom of the wings. This gives great strength to the wing.
Now you can cover the wing with paper OR masking tape and later use vinyl sheet for various colours..... or paint the paper using fevicryl colours....
You can similarly make ur aerofoils and fix them to the wing. Cut out the place for the servo and fix it there.
Best wishes....
Shobhit
pm no. 2Well...... good show.. I do not fix the spar earlier as probably because my wings are bigger i.e. the minimum span I have made in 3.75 feet and have been made of at least one inch thick sheet of foam. ANyway will try fixing the spar earlier if needed the next time. Also I prefer to use fevocol for all my general work and I use the fast setting epoxy only for the dehidral angles or places which need to be fixed in a few minutes.
ok... now for your answers.....
Wing tips.... ok. If you feel that you are going to bang the glider far too often then you may use Balsa wood wing tips. OR else... just cover it with computer paper ad fevicol.... Use a thinned fevicol (use water for thinning) to paste a wet computer paper where you want to give extra strength. While it is wet rub the thinned fevicol all over the paper and let it dry....
You may use computer paper to cover the entire wing for added strength. Fix it the way I have written above and the wing becomes very strong. But make sure that your spars are sufficient to give the strength required to the wing.
I generally use masking tape and then vinyl sheet to cover my wings. But off late have made an aerobatic model where the wing is just covered with paper and nothing else (a 4 feet span symmetrical cambered wing).
Do not for get to paint your model with fevicryl colours.....
Happy building your model.
Shobhit
Thank you so much sir for your guidance...