English Electric Canberra - in Depron of course

A modest start on the new B57D nose.

On the B2 the battery hatch was underneath. On the new nose the cockpit canopy will be removable so the battery can be inserted from above.
It was never was a problem but it did seem odd to 'arm' the plane inverted and then turn it over to launch it.

A lot of planking later and we have a more or less complete B57D nose.

It weighs 9.5 g so hopefully when complete and painted (silver) it will end up couple of grams lighter then the Canberra's 17.5.

Much sanding between one very thin white and 2 very thin silver has got as far as this.

Without the canopy it weighs 12.6 g
The base of the canopy hatch is lightly glued down so the planking can be added 'in situ' to make sure it achieves the right profile.

Silver nose and outer wing panels will look rather odd against the grey and black of the rest of the B2 airframe.

Nose now complete and ready to be glued on.


Hatch retained by a peg at the front and a magnet at the rear.
Over all it weighs 15.5 g so it has saved a measly 1.9 g but at least it is not heavier!

Nice work! I'm thinking about hatch retaining methods for my current build, tending to go for some sort of sprung loaded catch, I've not much faith in the peg and magnet method, I've had the battery hatch pop off twice on my caprice now despite a strong magnet and a tongue.

Having got this far I though it was about time I took off an original wing. After all if does not come away cleanly and damages the EDF tube the job would several times more difficult and might even mean building a complete new air frame.
Fortunately it came away pretty cleanly.

There was even sufficient servo lead available to be able to mount the servo but having pulled through all the spare I expect I will have to extend the servo wire on the other side.
There is no through spar so the next tricky job is adjusting the profile of the wing root so it exactly fits the nacelle so it can be glued on.

After much careful fitting the LH wing is fitted and glued in place

It is a bit alarming as it is just butt jointed to the engine nacelle. The concession to structural rigidity is it is to use Foam to Foam glue which dried rock hard rather than POR which always remains a bit rubbery.

In the course of removing the old outer wings I have found some significant internal damage on the wing between the fuselage and the RH engine nacelle which will need quite a big portion of the tissue to be cut away to give access for repairs.
Still I mustn't grumble as it was built over Christmas 2014/15 and 5 years is quite a long life for such a lightweight plane.

No spar? think that butt joint would worry me

I would be interested to know the wing load, not very high I suspect.

paul d
The whole leading edge is a big 'D' box and even in 2 mm Depron is plenty strong and stiff enough.
The engine nacelle is also a hollow box structure with formers and inner and outer skins.
So simply gluing the wing on is not a daft as it sounds as it just transfers the forces along the whole edge of the wing D box directly onto the same area of the engine nacelle skin. The Foam to Foam glue once fully hardened in an edge to edge joint very nearly as strong as the Depron itself.

It sounds odd but to achieve the lightest structure the trick is to not concentrate any forces to strong points but to leave them as distributed as possible. Hence my preference for a 'one piece' plane or if that is impractical to use a one piece 'bolt on' wing. Failing that to make any wing joint as far out as possible to minimise the bending forces it has to contend with.

The Canberra is at last beginning to actually look like a Martin B57D.

Under 250 g?
I suspect pretty marginal and probably down to the weight of the paint.

I'm no stress analyst but surely by butt joining the panel with as you've said rock hard glue is concentrating the forces??
just my thoughts obviously and you've clearly done it before ...

paul d
Your are correct but the 'rock hard' glue joint is spread spread along the entire length of the skin joint both top and bottom so in theory no part of the butt joint is loaded to any more then the 2 mm Depron skin itself has to bear.

The downside of doing it like this is that it relies heavily on all the construction joints being sound. An over load (a crash?) can 'spring' part of a joint which starts to weaken the whole structure. In other words a stressed skin structure can 'hide' damage so it is not easy to repair to an 'as new' standard - as I may find out!

I see your thinking....Oh just call me Paul btw .

As the servos are installed and tested the top side tissue can go on.

The task is to find a way to get the tissue tight, waterproof and coloured for the minimum weight as the all up incl battery but no ailerons is 237 g.
Ailerons, tissue and paint for 13 g? I have my doubts.