Armstrong Whitworth FK.3 - 3D Printed - Australian Flying Corps

[Ed Russell]

My modelling resolution for last year was to build more biplanes and multi-engines. I have been moderately successful (Gauntlet, Gladiator, Venturas, Ki-54 as well as single engine stuff) but I am carrying on the resolution into 2022. For a WW2 conventional builder this is a real leap - a 3D printed WW1 biplane.

A little company called Hobartville Hobbies (not in Tasmania as you might think, but an hour WNW of Sydney) is making a range of early aircraft flown by the AFC and RAAF. The first in the range was the DH.6 and the next is the AW FK.3, the Little Ack.

 

What you get is this

 

It consistes of 38 3D printed parts. a decal sheet and instructions. Here are the rather delicate parts

 

They have a similar feel to resin parts - not surprising as that is basically what they are. The striations associated with 3D printing are there but they are certainly not pronounced.

I sanded the larger surfaces quite lightly. I was tempted to spray a coat of Mr Surfacer or similar but I felt that it might obscure the detail. Similarly sanding more heavily will remove the striations but also remove the surface detail. Let's take a light approach and see how it goes.

Painting the interior and joining the fuselage halves are like any resin kit. The locating pins on the halves are very precise and the fit is good.

 

Gel cyanoacrylate cement works well and the minor seam blemishes were filled with ordinary model filler. I used Perfect Plastic Putty which is fine for very small seams but not much else.

The underside had a bit of a reverse curve and this was filled with Tamiya White Putty.

 

Next we can look at the wings.

 

[Brandy]

I will definitely follow this as I have it on my "must buy" list, and will do so very shortly!

 

Ian

[Marklo]

IGood to see more obscure biplane. Edging me towards that FK10 (yes I know is a quadruplane) I keep threatening to build will follow with interest. 

[mark.au]

Following along with interest.  The subject isn’t in my usual area of interest but the kit certainly is; I’m off to check out Hobartville’s website.

[Ed Russell]

The next step is to attache the wings.The instructions show a butt joint but I don't think that will be adequate. Some pins will help with alignment and strength. The wing was previously marked from inside through a hole and then placed in a pillar drill (a Dremel on a stand) to make a hole.

 

 

Similarly the upper wing is in three pieces. This is presumably a limitation of the size of the 3D printer platen. Again, some pins are used to secure the three pieces together. I suspect subsequent events may show the single pin in each joint is insufficient and I would suggest anyone building the kit put two pins per joint.

 

 

To their credit Hobartville Hobbies is interested in continuous improvement and later kits will have at least dimples where the holes for pins can be drilled out. This can be done with precision in the 3D drawing and should really help.

[heloman1]

That looks rather neat and an interesting subject. Good luck tot he company producing these kits.

 

Colin

[Courageous]

Looks very interesting, never seen a 3D printed aircraft. I'll tag along.

 

Stuart

[Ed Russell]

Next thing is to sort out some colours. Clear doped linen is a variable colour - pretty much anything in the cream area will be fine. Not H74 or H81 - too yellow. H71 and H148 look about right. PC.10 is made from lampblack and yellow ochre. One of my friends who worked for Dulux had a go at making this some years ago. Yellow ochre varies a lot but the mix is always a more-or-less brownish green. Probably HN5 and X114 are the only ones I would reject here - too bright. Probably any green colour in the range would do.

 

 

It's also time to paint some of the small parts. The struts are very fine, Fortunately there was a spare one as I broke the pin off one - it's very easy to do as they are so fine.

 

 

To make life easier I will go with one of the kit schemes - something I hardly ever do!

 

 

[Ed Russell]

Looking at the kit colour schemes this one looks nice.

 

 

The most accessible reference for them, the ADF-Serials board hedges its bets with uncertainty on the provenance of all FK.3 pictures

http://www.adf-serials.com.au/FK3.htm

but A8099 will have to do as a subject. Looking at a high resolution copy of this picture and particularly the fuselage roundel, it is apparent that the colour of the fuselage sides is not white as suggested in the kit instructions but something a little darker. Logic suggests Clear Doped Linen so that's what we will go with. Using Humbrol 148 the undersides are given two fine coats.

 

 

The wooden parts appear to be in a colour pretty close to CDL but not exactly the same so X107 is used but any cream would do.

[Ed Russell]

Next we spray some Humbrol 150 on the upper surfaces, having masked off the undersides and the engine cowling which was often painted Battleship Grey whatever that is! I suspect it's not the colour they painted battleships in WW1.

 

 

I'm glad I went with a thin coat as it looks too "green" for my notion (only slightly reinforced by paint experiments) of what PC.10 might have looked like. I think maybe a slightly darker and browner version might be better - Humbrol 86 maybe?

[Ed Russell]

A coat of Humbrol 86 looks a lot better. More brownish, less greenish but still compatible with a yellow ochre / lampblack shade.

 

 

Another glitch in the instructions is the roundel position.  They call for an outboard position but every picture which shows them has them more inboard. The decals also appear to be in the WW2 shades of red and blue rather than the brighter WW1 shades. The blue is acceptable but the red is very brown-looking. I will use them but put a brighter red disc over the centres. The underside roundels have white outer rings - not correct for roundels over CDL. Spares box job.

[bigbadbadge]

This looks like a lovely kit, great work so far Ed.  Humbrol 148 is a good choice, have used the same on my RFC Camel and it looks really pleasing.

Great progress on this.

Chris

[Brandy]

Looking good so far. Absolutely correct about the underwing roundels, or any roundels on a CDL background. Also may not have had the outer rings on the upper wings unless the aircraft you're depicting is shown as later in the war (1917/18).

 

My kit is on it's way, I'm looking forward to inspecting it!

 

Ian

[Marklo]

On 1/21/2022 at 7:34 AM, Ed Russell said:

the engine cowling which was often painted Battleship Grey whatever that is!

Afaik it’s a light blueish grey. I have an AK WWI set that has a bottle of it. Think usaf light ghost grey.  
 

The Humbrol 86 looks pretty good. Again I use the AK set for PC10. Which is darker but a similar hue, I suspect that PC10 should be more brown owing to the fact that the fliegertruppens nickname for the RFC was the sparrows and sparrows are predominantly brown.

Edited January 22, 2022 by Marklo

[Ed Russell]

3 hours ago, Brandy said:

the aircraft you're depicting is shown as later in the war (1917/18).

I think the period we are looking at is mid-1917 so I wold say the white ring is correct.

 

1 hour ago, Marklo said:

I suspect that PC10 should be more brown

Using the actual ingredients for PC.10 you can mix a variety of colours. Actual references from the time are not common but I gather a "brownish green" rather than "brown" is more common. There are also references to the colour being darker and more brownish later in the war. Different source of yellow ochre?

 

10 hours ago, bigbadbadge said:

Humbrol 148 is a good choice

I shall use it for my next WW1 build!

[Marklo]

2 hours ago, Ed Russell said:

Different source of yellow ochre?

Funny you should say that my AK set comes with PC10 early and PC10 late.

 

I’d suspect that given the mix of ochre and lamp black that the actual aircraft would have differed by paint batch and factory. And seeing how any examples we have are either restorations ( blue Matilda’s anyone ?) or subject to 100 years of age in we’ll probably never know the exact shade. So it comes down to my two preferred terms, pleasing colour and plausible colour. 
 

Basically if it looks right it is.

Edited January 22, 2022 by Marklo

[Ed Russell]

Some decals from the spares book.

 

 

In daylight it looks just a bit darker than the pictures.

 

 

Next comes making it a biplane.

 

[bigbadbadge]

Oooooo looking very nice indeed. Looking forward to the struttery and rigging. 

Great work

Chris

[JWM]

Very interesting! Certainly the 3D kits will be with us more and more frequently. Ed, it is great, that you tried with good results!

Regards

J-W

 

[Brandy]

It does look as though some work is needed reducing the rib effects, especially under the wings and tail. I'll reserve final judgement until I receive mine though.

 

Ian

[Ed Russell]

4 hours ago, Brandy said:

some work is needed reducing the rib effects

You are quite correct - they are too prominent. For this "quick-build" to give the manufacturer some feedback I only sanded mine a little. One of my colleagues suggested taping over each rib, applying Mr Surfacer, removing the tapes and then sanding down the wing ribs.

[Ed Russell]

I followed the instructions and attached the four cabane struts first. Then using a simple jig (a balsa wood I-beam) and lightly fitting elastic bands I positioned the upper wing. Then I could tip it forwards and fit the interplane struts.

 

 

 

Unlike some biplanes I have built recently they fitted perfectly. I was a bit dubious about the teeny-weeny strut ends (and managed to break one, but the kit included some spares - a nice touch) but they fitten exactly into the teeny-weeny holes in the wings.

There are some markings on the rear fuselage, indistinct even on a hi-res picture but I think they are the lift points.

 

With the struts in place, rigging is next.

[Ed Russell]

Using stretched alloy wire for rigging, the aim is to create an impression rather than reproduce every piece. Real rigging is quite substantial stuff and using the thinnest material you can find is not necessarily accurate.

 

 

 

Once the rigging is mostly complete the undercarriage can be added. It is essential to get this structure square and level otherwise the aircraft will not sit properly. It was positioned in what appeared to be the correct setup but a small problem arose.

I had previously decided to make the propeller removable for ease of transport and noticed that spinning it hit the undecarriage skid!

 

 

 

 

I was too engrossed in removing and re-setting it to take pictures but it eventually went together okay and the finished result looked like a pretty good representation of a FK.3 aircraft. I will do some pictures in RFI but here's a quick shot of the finished result.

 

 

 

[Ray S]

That came out well! This manufacturer looks like they could produce some beauties!

 

I will have to check them out.

 

Ray

[Ed Russell]

RFI here

https://www.britmodeller.com/forums/index.php?/topic/235105786-armstrong-whitworth-fk3-little-ack-australian-flying-corps-hobartville-hobbies-3d-printed/