Winter build project: Wolfgang Matt’s ATLAS

Chris, why the concern over 5 grams? It is not an indoor flyer! There could be no end of factors affecting weight. Density of balsa, amount of glue, humidity content of balsa.... number of 3 inch nails... :lol:

I have just added 65 grams of Lipo to my Curare for receiver/servos and my doubling up of fuselage items, tons of CA medium and I am not concerned, just a pain to adjust the CG again with so little space to move about. (Should've gone IC ) It still comes out less than 2.4 kgs fully loaded.

PhilF51 wrote: Chris, why the concern over 5 grams? It is not an indoor flyer! There could be no end of factors affecting weight. Density of balsa, amount of glue, humidity content of balsa.

You've completely missed the point, Phil! Chris is showing that both models weigh 'exactly' the same.

I'm way behind on my blog, mostly because I just want to get this thing done and in the air, it hurts not having a plane to fly

But I thought I'd put up a few pics here.



I've still got the leading edge of the wing to do, and I'm putting it off because I'm not sure how best to approach doing it, so any tips or advice would be most welcome.

Looking good Chris How did how do you cut the balsa round the retracts
Regards John

For the leading edge Chris I think I would stick a length of balsa , slightly over size to the LE. Then transfer the full root and tip section to each end of the wing either by attaching templates or by drawing. Find the max chord of the root and tip, transfer to the balsa and then draw a connecting line along the full span. This should give you a sanding guide and account for any washout and/or preserve a semi symmetrical wing section ( I assume yours is symmetrical)

Stick masking tape to protect the veneer and plane and sand until all bits of the balsa that aren't leading edge shaped are removed Remove the masking tape for final finishing.

If you have intermediate wing sections you could create some gauges to check the LE shape at various stations along the wing. Otherwise its down to checking with a straight edge and MKI eyeball.

It'll be interesting to read other peoples method of adding a leading edge.

Or you could just attack it with a sanding block until it looks about right

Hi John, the balsa around the retract was cut with a scalpel and then sanded, but the cut out was already established in the foam, so it was just a case of sanding back to the foam. I think it would be a bit more tricky if the balsa was unsupported like in a built up wing.

Thanks Alan, the leading edge is already glued on, so I'll mark out the profile at either end, and center line and just go for it, I guess.

Chris, You surprised me, I thought you'd suggest a belt sander, I didn't know you did subtle and refined

Attack it with your razor plane.

Use the plane to cut the leading edge into a trapezium shape. Then round the trapezium to a rough leading edge. Then 120 grit sanding block. Should take about 10 minutes for each wing.

The razor plane it was... all I can say is I might need a little practice, but I don't think it's disastrous.

I've been holding back the perfect piece of balsa for the ailerons, it had a good stiffness and not too heavy, but above all was dead straight. Then the blasted thing decided to go banana shaped on me when I cut in two, it must have had quite a lot of tension in the wood. Luckily I cut it over size so was able to get it back into shape. Just goes to show how wood can be deceptive.

With the wing joined, I'm now at the position of aligning things, I guess the first job is the wing to the fuselage, so that I can make the belly pan and sort out the securing bolts.



I'm marking the distances on the aluminum, as a wobbly ruler just became a pain in the neck.

So A=A, B=B & C=C well hopefully they will, is there any other measurements I should make? the nose is angled so there's no convenient point to measure off.

My glassing was a bit uneven so the wing seat needed just a little refining (read a lot of sanding)





But it's looking better now, I just hope I've not adjusted the wing incidence or list to one side.