A bigger DH Venom

I am about to do what I said I would not and build another plane.
The 50 mm EDF sitting on my bench annoys me intensely so I have decided to use it is a bigger Venom.
My smaller sub 250g 40 mm EDF Venom flies remarkably well so a bigger one should as well.
One advantage of the Vampire/Venom layout is the duct length is relatively short compared to say a Hawker Hunter.
 
I should be able to print the duct in LW-PLA.
The Venom 50 will have a span of 40" (1016 mm) compared to the 30" of the smaller Venom. It will definitely not be sub 250g as the EDF, ESC and battery alone come in at 200g!
       

The first attempt at printing a 'lofted' LW-PLA duct.
 
Only a test so neither the full length nor quite the right shape but it is now just a case of adjusting parameters rather than working from first principles.
The LW-PLA  duct will be made up of 3 'vase' printed parts glued together & should weigh about 17g..
There will also be L & R 'inlets' probably in PLA for rigidity. 
 

A CAD view of what should be the final design. The angled wing root pieces will be separate
 
3 parts, although really only two, as each "leg" is identical just rotated through 180 degrees.
 

Printed off the three parts of the duct, total 1hr 45 mins, and glued them together. The first part is a good fit over the front of the EDF which has a removable bell mouth.
 
The LW=PLA parts are glued together edge to edge with a heavy weight tissue bandage over the outside of the joint glued on with PVA.

Now the fun begins, creating and adding the fuselage formers so their internal cut outs fully support the duct.    :

Only slow progress but the formers and the root rib that create the fuselage shape around the duct are at last in place.
 
As a method of construction it is a complete nightmare indeed I have not fully worked out the sequence to fully complete the fuselage!

 

One reason I keep opening up aeromodellers is to see the evolution of these 'puzzles' that you create and follow the story about how you work out the next steps....

Rather slow progress but I am still working on the bigger Venom.
 
The cockpit area has been added to the front of the duct and the EDF with its exhaust tube glued on the rear.
A start has been made on the fuselage underside planking.. The top side will have to left substantially clear to install the "Electrics".
Once the underside planking is complete the wing roots out to the booms will be next to strengthen the flat parts of the duct so the EDF can be test run at full power.. 

Still slow going but with Zoe and Robin down in Babbacombe working on the cottage I am the only grandparent available to baby sit or even house sit for my daughter.
Anyway the wing ribs at the tail booms are now in place.
 
There will be several supports added between the outer skin and those flat duct areas to resist collapse.
The wing section at the boom position is scale.
 
 A thin 10% 'laminar flow symmetrical' section undoubtedly used as a way of getting maximum speed with the technology available at the time. Probably did not make the Sea Venom ideal for shipboard use. Indeed later versions had small fixed leading edge slats right at the tip presumably to reduce the possibility of a stall starting at the tip on approach to the carrier.
However the scale wing section does seem to work well on a low powered lightweight EDF where the speed of approach is not a pressing problem.      

It never rains but pours! I am getting near to wanting to print the nose cone for the bigger Venom but today the heated bed packed up, in fact rather worse as it was the bed thermocouple that failed which the printer recognises immediately, lets out a loud waring tone and halts the printer.
Assuming I would have to replace the bed I took the bed off the carriage. On inspection I noticed that one 'leg' of the thermocouple had become unsoldered from its 'track' on the underside of the bed.
Miracles of miracles I manged to solder it back!
 
The re soldered joint is the one by the red arrow.
Now I have just got to put it all back together and reset the bed height from scratch. Takes a while to get it right. 

 

The wing roots, or at least the undersides, are on.
  
It is even beginning to look like a Venom. 
The upper root surface has just the outer edge which allows the wing outer panels, when complete, to be glued on yet still leave access to run the aileron servo wires into the fuselage.
With the wings in place the booms can go on and the elevator servo wire, it goes down the RH boom, to be run into the fuselage. Only then can the wing root top surface be completed.

It will be another of my classic "everything permanently built in" planes. .
 

The first wing panel, not fixed yet just resting, shows that the 'Bigger Venom.' will indeed a bit bigger than the sub 250g one!.
 
A view of its 'no rib or spar' wing construction.
 
Its all just Depron.
.
 

The wings are now on, although still some tidying up to do.
 
The booms are next. A bit tedious as each is in effect a small fuselage and being so far back they need to be light! .

After much thinking about how to actually make the boom I decided to print the required formers.
 
There are in PLA for rigidity using my single sided diagonal braced construction that I use for wing ribs.
The 6 reduce in size towards the tail plane but different in X and Y using the CURA scale feature. The hole in each former is to run the elevator servo wire through.
The booms represent the last tricky part to build, Once they are correctly in place the tail plane itself is comparatively simple. 

Making a bit of progress. The basic boom structures glued in.
 
The tail plane, still under construction, will be glued on next so the elevator servo wire can be fed down the boom. Only then will the boom top and bottom skins be added in the form of several really narrow planks.

Tail plane fixed, elevator servo in and its servo wire run down the RH boom and into the fuselage. All servo tested OK
 
The tops of the boom have been planked in 2mm Depron. Each requiring 6 very long narrow planks. Bottom of booms still to do  There will be 24 in all. Awful slow to do..
And
My daughters dog Bandit who stayed for the night along with grandson Casper. He has now gone home but surprise, surprise, the dog is still here and very relaxed he is too!