English Electric Canberra - in Depron of course

My 'test' exhaust tube with the flared section to bring the 22 mm duct to the 30 mm of the EDF.

This 'after body' cone will be suspended in this part of the duct to keep a constant cross section area as it changes from an annulus as it leaves the EDF to the circular duct.

The test duct with the EDF in place.

The tube of UHU gives some idea of its size.
This 'scrap' duct is being built to test the method of construction and is about a far as it need go.
An exact fully clad and working Canberra duct is next.

now that looks impressive Simon.

love the way you work this stuff.

Having satisfied myself that it can actually be made, the beginning of the 'working' Canberra nacelle.

With all the correct sized formers in place it is also little longer than the test version.
The paper duct and formers weigh 2.4g
Next is the planking.

As it turned out the above duct had a small error, the taper was too short - bit it was late.
So the larger wooden mandrel had to be re-machined to a slightly shallower taper and the front section of the duct rebuilt.

The really fun bit will be suspending the after body in the duct on 3 tiny litho fins and it will have to be done after the planking is complete and the mandrel removed.

Just as an aside formers 3 & 4 (from the left) are quite substantial and coincide to the position of the wing 'D' box so should be able to handle the loads.

It looks a bit like a drone, are you sure you're making bagpipes?

It has taken a while but the nacelle is now fully planked - all 23 of them - and the mandrel removed.

The after body installed in the duct.

The after body looking up the rear of the duct.

The nacelle weighs 10.4g
I was hoping to show the EDF installed but the one I selected doesn't work!
The other does but by then it was getting late.

wow that looks great simon.
how do you do it.

Now I have a problem.
I was about to order a replacement 30mm EDF from HK but I then noticed the current version is slightly different. It has a 9000kV motor instead of the 10200kV on the only 'good' one I have.
This means they are likely to have slightly different levels of thrust.
With such a light plane and the nacelles being quite far out along the wing I dare not risk 'odd' EDFs so I am faced with having to buy a new pair of EDFs which is a bit daft as the only reason I selected the Canberra in the first place was to 'use up' the two that I already had!

I now have to decide whether to buy 2 and continue as planned or stop the Canberra build altogether and just do comparison tests with the one EDF I have to determine how much thrust is lost in the nacelle for the benefit of some future build.

There is one way Q, but maybe you wont do it . Sooooo I will !!!!
I for one, dont want to see this thread end, so , has anyone got one of these EDF s knocking about doing nothing that can be donated to Q to continue this build ???? Over to you folks

Garry

251733732380 One on ebay, any use?

Never though of looking on Ebay. Doh! .
Alan many thanks - one ordered.
Lets hope when it comes (January ) it is actually the one in the picture.
The thrust given is way more than the spec for the HK version - like twice as much and 3 times the current!

The EDF installed in the duct

I wanted to post a video of it running but these little EDFs are not the best balanced in the world and in the Depron nacelle it is loud and its midnight!

First I needed a simple test stand to measure the thrust.

Very simple

On the scales is generates a fraction over 2 oz thrust drawing 7A.
I makes quite a racket too!
Now to start thinking about the rest of the airframe

not really silent flight is it.

well done though sir.

A little bit more drawing to show the likely construction of the wings.

All Depron with tissue covered panels aft of the D box. The tail surfaces will be singe sheet Depron with an inset balsa spar. Like the nacelles the fuselage will be all planked.
With a total of 4 oz thrust I have a bit more weight to play with but with a 14A draw the battery will have to be bigger too. Ideally I would like a 1300mAh 2s to keep close to a 10C (6 minute) flight duration but a 950mAh Nano-tech 25-50c at 1.6 oz looks more likely.