60" Handley Page Hampden and Vickers Wellesley Scratchbuilds

[baz49exe]

Hi folks, I've just completed a 60" Hampden build to the point where it has just successfully completed its "bare bones" maiden.
It's the latest in a number of warbirds built from scaled up downloaded 3 views and very cheap 2" thick EPS wall insulation foam. The fuselage forming method used the threaded bar and hardboard formers method which hit me one evening as I was pondering how to make a GWS style fuselage from basic foam..
I am posting this as it is such a cheap way of building a relatively large scale warbird which will fly, even if the subject is an unconventional aircraft such as the pod and boom Hampden. This is what it should look like ( Pic 1)
I think it's a striking looking aircraft but then "Beauty is in the eye of the beholder" as they say!
The aim is not to document in detail as that has been done on previous build threads but to give an over view of this build as this method can be adapted to almost any airframe build.
The 3 views were downloaded and placed into PosteRazor to scale and tile in A4 which is convenient to print out on my home printer. These were just the job as they contained fuselage sections with the section position marked on the plan view :- perfect!.
The centre line was not marked onto the sections but it was easy to draw one onto the plan view and copy the position of the threaded rod onto the sections.
This model was a challenge as the pod with the very narrow boom rear fuselage made the hollowed foam construction only suitable for the front pod and something had to be found for the boom construction.
To make the pod the formers were cut from hardboard and drilled at the centre line point to take the threaded rod. Starting from the nose they are then placed onto the rod and positioned by reference to the drawing, held into place by a nut each side. Foam block is added between the formers to fill the gap and after the nuts are tightened the whole issue is hot wired around the formers to make a section of fuselage. The assembly is broken down, the sections are cut away at the centre to form the fuselage interior and then glued and clamped together using the rod to form the finished hollow fuselage.
I'd had success using 12mm by 4mm spruce strip set on edge into the foam panels as wing spars right up to 64"span in the Wellington where the spruce had proved light and plenty strong enough for the job so it seemed obvious to use the same method for the boom and set a top keel into the pod when it was constructed to form the boom when profiled by adding foam sections to the spruce.(Pic 2)
Foam sections were added to the spruce to form the remainder of the boom and a section of spruce was left exposed to take a balsa tailplane mounting plate ( Pic 3)

[xmech2k]

Great build, Baz! I love to see unique scale models. If I ever get my act together I'd love to build some of my own. Meanwhile, people like you give inspiration.

Any more pics? You said you got to maiden it?

[baz49exe]

Hi xmech2k,
I used to feel like you and I was convinced that I needed balsa wood and a full set of plans to build a model.
Eventually I realised that you don't and that it's actually as easy, or easier to build from 3 views and foam using this method.
The difficult part is starting, honestly, it's far easier after that!

It's been maidened and has flown in raw foam a few times. I'm now adding the finish and I'll add more pics.
There's more build info on this Wellington thread:-
http://www.wattflyer.com/forums/showthread.php?t=60141

[baz49exe]

Next I needed to make the main wing so that it could be used to mark out the fuselage wing seat.
For me the simplest way to build the wing was to first build an accurate main spar out of 12mm by 4mm spruce strip. The correct size and dihedral angles can be taken directly from the enlarged 3 views. In this case there were three components to the spar, the centre and two outboard wing sections. The three spar pieces were joined at the correct angle, at the two outboard joints, by ply plates and left to set over night.
The foam centre panel was cut to size and then the profile formers were pinned to the edges, the wing was hot wired to shape and a groove was cut on the underside to take the spar. The same process is used to make the outer panels which are glued to the spar assembly next.
The fragile trailing edge was cut away and balsa strip was glued in its place and the aileron bays are also removed and a balsa sub spar was glued to the rear of the bay to provide a secure fixing for the balsa ailerons.
For the first time in a larger build I used 6mm depron to cut out the twin fins and the tail plane. The rear of the tail plane had a 6mm spruce strip attached as a mini spar and elevator attachment point and a similar balsa strip was added to the front of the elevator.
The wing seat could now be marked out and cut away to give an ARTF kit of parts. ( pics 1 & 2)
I couldn't resist placing them all together at this point to see how things were coming together.( pics 3 & 4)

[riverrat]

Barry!

Looking good!!!!!!!!!!

You are still keeping up your
innovator image!!

Regards
Jimmy

[baz49exe]

Hi Jimmy, how are you? How's the building and flying going?
I'm not sure about being an innovator ( many thanks!) but I'm having so much fun with this that it must either be illegal, or I need to pay lots more tax on it, or both!!

Cheers, Barry

[xmech2k]

Love it, Barry! I love unique models, and that one sure is. The wing looks like it could be a scary flyer, though. Will you add washout at the wingtips?

[baz49exe]

Next step was to sort out the main wing fixing method. It's not usual as I hated probing with a nylon wing bolt to try and find the blind nut buried deep in the fuselage, so I turned it on its head and placed 3mm steel bolts mounted on ply plates into the fuselage so they pointed downwards and the wing mounting lugs can be simply slid over them.( pics 1,2 & 3)
The lower fuselage cut out was glued to the bottom of the wing and a ply mounting plate was glued into it facing forwards to slide over the bolt. At the rear of the wing a simple hole drilled through the trailing edge is all that's needed. This method locks the wing to the fuselage and prevents the wing seat from opening up under pressure, returning structural integrity to the airframe. ( pics 4,5 & 6)
The engine nacelles were formed in the same way as the fuselage and were cut in half and then the lower halves were fitted to the lower wing profile and glued into place.

[baz49exe]

Hi xmech2k, I was worried about tip stall when I saw the wings as well.
The Wellington has similar, not quite so extreme, taper and that shows no signs of stall so I did the same with this wing and included washout into the wing when I hot wired it as well as carving plenty into the wing tips when I added them.
On the maiden I took the Hampden up high and cut the throttle while facing the model into wind and applying increasing up elevator. No stall at all!! It just mushed and settled. Powered away with no trouble at all. Phew!!

[baz49exe]

The 10mm square spruce motor mount was glued into the front of the lower nacelle so that the motor mount would place the shaft on the centre line when the motor was in place.
Next the top of the nacelle front plate was cut and glued into place. The battery access hole was cut into the front of the plate and the ESC support and battery retainer was formed from old ice cream sticks. ( Just great for the job)
The profile of the upper nacelle was drawn onto the wing and the wing was covered in cling film.Now the remainder of the upper half of the nacelle could be trimmed to the wing profile and spackled to give a good fit when sanded into shape.( pic 1)
When dry it was cut away from the front ring and skewer retaining pegs were added to the front and a magnet to the rear. The motor and ESC were test fitted, the lipo was slid through the cowl ring into the battery bay and the underside of the nacelle top was recessed to allow the ESC / lipo connections to sit on the wing.
The tail plane assembly was now glued to the mounting plate and I could now think about installing the controls.( pics 2 & 3)
The 9g hextronic elevator servo was fitted into a box under the tail plane and the extended wires were set into the foam on the underside of the boom to exit in the radio bay.
(pic 4)
Twin 9g aileron servos were set into the underside of the wings and the extended leads were set into the foam to exit inside the radio bay also the ESC signal wires were channelled beneath the wing from the nacelles to the fuselage. .
The whole model was spackled,sanded and covered with 5 momme silk and water based varnish.
Looks like the cowls come next

[Bill G]

Looks like it's coming along well Barry.
Another good subject to model after this would be the Heyford. Such an odd looking plane, but I keep gaining interest in it since I first saw an excellent build some years ago in Flying Scale. I've been thinking about building one for years. Maybe one of these days.

[baz49exe]

Hi Bill, I've looked at the earlier Handley Page aircraft as well including the Heyford and the Harrow. Of the two the Harrow looks a far easier build without the extra wing and braces of the Heyford, ( I'm lazy) however a slow flying Heyford would look amazing in the air.
Both have the advantage of being fixed wheel aircraft and they'll give me the chance to ROG without the problems of retracts which are not really suitable for our rough strip. I'd rather build an aircraft which didn't have fixed UC as a hand launcher than have it fly around with wheels hanging down.

[baz49exe]

The cowls are simply formed by heat shrinking pop bottles over a plaster mould. The mould is cast around a plastic pipe so that the completed cowl can easily be knocked off the mould by pushing a rod through the pipe.
( pic 1)
This cowl fits an AX-2308N1800/5430 1800kv Brushless Motor and 7 by 6 APC prop perfectly so I have standardized on this set up and scale all my multies so that the cowls match the available set up. ( just being lazy but it makes life so much easier.)
The cowls are simply attached by servo screws to wooden blocks glued to the face of the firewall.
The model was test flown at this stage and to my amazement it flew straight off the board with two clicks of elevator trim being all that was needed. (pic 2)

[baz49exe]

Next part was to model all the glass work on this aircraft and that included a fully glazed nose, cockpit, upper gun position and lower gun position.
As I thought it would be the most difficult I started with the nose and made a complete nose section mould, carved from lightweight interior wall building block.True to form I picked up a broken block for nothing from the local builder's merchants.
As I feared the whole nose was too large to form from one 2 litre pop bottle so I had to cut it into an upper and lower mould and join the glazing on the centre line.(pic 1)
A balsa back plate was cut to hold the nose section to the fuselage front and the two glazed sections were glued into place. Bamboo pegs and magnets will hold the nose into place.(pic 2)

[pattern14]

Good on you Barry for doing this build thread Lots of these little known early bombers were classics just waiting to happen, and the Hampden is no exception. On a more contemporary note, do you have any photo's of your hotwire method of cutting foam wings, templates and such? Do you cut them in sections and then glue them together, or use a large bow and simply make two halves?. Keep up the good work

[baz49exe]

Hi Michael, I thought it might be useful to anyone looking to build a cheap scale model so here it is.
I use a simple bow built like a bow saw of yesterday. The cutting wire is fishing trace 0.04" I think, off hand. Power is supplied by an old 12 volt tractor battery charger but as the ammeter shows 2 amps in use I guess any decent car battery charger would do.
The wing outlines are copied from the drawings onto paper and cut out. Then they are placed onto the flat 2" thick foam sheet and drawn around.I used to hot wire the wing blank at this stage but I now find it quicker and more accurate to simply cut the blank out with a sharp carving knife.
You will always need two blanks, left and right as the wing needs a centre section profile cutting former which needs to be attached to the side of the core at the centre line and you need a similar former at the tip of the wing. If there is an out board wing panel with dihedral you need mid wing formers as well and then you're looking at cutting four panels.
I simply cut the formers from hardboard with the patterns from the drawings stuck onto them. For me, the easiest way to attach the formers to the panel ends is to drill small holes into them and use panel pins pushed through the holes to nail the formers to the foam.
To stop the foam blank from moving while I draw the wire through it I place lead diving weights from my belt onto the blank.
In checking I've found that there are no wing cutting pics on my computer. Then I realised that it's because I've always got my hands full when I'm cutting a wing core.


Hope this helps,
Barry

[baz49exe]

These are the parts which I think will never turn out OK but in the end they somehow do so.
The cockpit and the upper and lower gun position moulds were carved from the lightweight block ( pics 1, 2 and 3 ) and pop bottles were heat shrunk over them to produce the glazing.
The clear plastic parts were trimmed to fit and glued into place on the fuselage and lower wing, having first painted the area enclosed by the glazing matt black.
At this point the underside matt black camouflage scheme was applied using thinned blackboard paint ( which I was trying for the first time) and the top side dark earth half of the scheme was added using thinned Humbrol plastic model enamel. ( pics 4, 5 and 6).
The thinned black board paint went onto the airframe very well, despite my concerns, I'll just have to resist drawing onto it.

[soarrich]

This is a joy to watch. Thanks

[xmech2k]

Looks great! Thanks from me too for sharing! Can't wait to see the finished product. Are you going to put retracts in it?

[warhead_71]

Great build, Baz! (Barry?) This is one of those planes that look so awkward (IMO) that I find them beautiful, like the Stuka, Westland Lysander, Handley Page Heyford, or Curtiss Shrike).... it just has so much "character". I do a similar thing and build many planes at a scale that I can re-use peanut jars for the cowls... so they all end up being about 1/9-1/10 scale with radial engines Keep up the good work!

-Warren

[baz49exe]

Originally Posted by soarrich

This is a joy to watch. Thanks

Hi Soarrich, thanks very much
I'm glad you're enjoying it as I'm having a ball building and flying these bombers, it's just amazing fun

Barry

[baz49exe]

Originally Posted by xmech2k

Looks great! Thanks from me too for sharing! Can't wait to see the finished product. Are you going to put retracts in it?

Thank you too xmech2k
Even though they come in at around the 3lb AUW mark and I could easily install lightweight electric retracts I don't think I will as we have a rough grass landing strip which is very hard on retracts so I prefer to build them as hand launchers and just belly land them.
Do you have a strip suitable for retracts?

[baz49exe]

Originally Posted by warhead_71

Great build, Baz! (Barry?) This is one of those planes that look so awkward (IMO) that I find them beautiful, like the Stuka, Westland Lysander, Handley Page Heyford, or Curtiss Shrike).... it just has so much "character". I do a similar thing and build many planes at a scale that I can re-use peanut jars for the cowls... so they all end up being about 1/9-1/10 scale with radial engines Keep up the good work!

-Warren

Hi Warren and thanks very much.
Like you I love unusual planes that have a certain awkward character about them. Have you seen the version of the Lysander with a turret mounted in the shortened tail? It is really ugly and I believe it was designed as an emergency measure to specifically fly up and down the beaches strafing the ground in the event of an invasion in 1940.

Barry

[xmech2k]

Originally Posted by baz49exe

Thank you too xmech2k
Even though they come in at around the 3lb AUW mark and I could easily install lightweight electric retracts I don't think I will as we have a rough grass landing strip which is very hard on retracts so I prefer to build them as hand launchers and just belly land them.
Do you have a strip suitable for retracts?

Yes. My club has a 150 meter runway. I love it since a good landing is one of my favorite parts of flying. And I hate it, since I feel pressured into putting retracts into every plane I own! I already put retracts in my PZ Corsair, and I'm finishing the install in my Dynam Turbojet. (Cessna Citation)

Well, that's a lot less weight and complication you don't have to deal with anyways. Still doesn't take away from a great build!

[baz49exe]

Originally Posted by xmech2k

Yes. My club has a 150 meter runway. I love it since a good landing is one of my favorite parts of flying. And I hate it, since I feel pressured into putting retracts into every plane I own! I already put retracts in my PZ Corsair, and I'm finishing the install in my Dynam Turbojet. (Cessna Citation)

Well, that's a lot less weight and complication you don't have to deal with anyways. Still doesn't take away from a great build!

Your own 150 metre runway is a luxury most over here can only dream of
You're right about retracts, there are pros and cons and the weight loss makes a big difference to a small model. ( I will keep saying that to console myself)