CAC Wirraway A20-502 "The Rocket" in 1/72 scale

[Derek_B]

Another Wirraway project I have on the go is the MPM Models 1/72 kit, which I'm planning to build as the legendary A20-502, known affectionately (and ironically) as "The Rocket". This aircraft served with No. 5 Squadron in Queensland and New Guinea, racking up an enormous number of sorties over its long life. To quote the West Australian newspaper, Friday 20th April 1945:

 

ANCIENT WIRRAWAY.
Achievements of the Rocket.
MELBOURNE, April 19.-Now operating with an RAAF Army co-operation squadron in the Solomons is an Australian-designed and built Wirraway which is claimed to be the oldest single-engined aircraft flying in operations in the South-West Pacific area. Known as the Rocket, this Wlrraway, which began its career with an RAAF Army co-operation squadron on March 10, 1942, has completed 953 sorties and flown almost 1100 hours. It has out-lived four engines.
Last month, when the Wirraway celebrated is third birthday, Flying Officer Ted Reynolds, of West Maitland, NSW, flew it on a tactical reconnaissance over Japanese positions at Bougainville Island. The Wirraway has dropped smoke bombs as target markers for Corsair fighter-bombers of the RNZAF. While the New Zealanders' dropped their 1,000lb bombs on Japanese positions it flew low over the target to observe the results. It has pinpointed numerous targets for the AMF. It has flown so low that once a pilot was able to signal base that a wounded Japanese had blood trickling down a leg.
Other important jobs it has carried out include the re-charting of maps of Bougainville Island. On survey work it has flown on steady photo reconnaissance flights. It has acted as mail and supply dropper to front line troops. In artillery reconnaissances it has been shaken by mortar fire whilst flying above the barrage. It has dive-bombed targets inaccesible to high-speed bombers, and fighter-bombers.
Now in its fourth year of Army co-operation work, the Wirraway is under the care of Flt-Lt F. T. Binns, of Sydney, NSW, an engineer officer. "The fact that the Rocket has never had a major misfortune is not the least of its claims to fame." he said. "The nearest it has come to disaster is wing tips damaged in ground loops." Flt-Lt Binns considers the Wirraway the ideal aircraft for Army co-operation work, because of its handling qualities and complete lack of vices. Wirraways are doing particularly fine work in the present campaigns, giving splendid co-operation to the AMF.

 

The aircraft ended its life during a particularly exuberant New-Year's eve party in January 1946, when it was burned on a bonfire together with a CAC Boomerang!

 

Sadly, the aircraft had been approved for preservation in the Australian War Memorial in Canberra due to its longevity and high public profile, but the signal from RAAF headquarters arrived at the squadron after the deed had been done!

 

My plan is to model this aircraft as it appeared in May 1944 when used in some supply dropping tests at Mareeba, Queensland. It was fitted with rectangular supply canisters (different to the later cylindrical "Storepedo" designs used in New Guinea) plus a message pick-up hook. Luckily I have a copy of the factory drawings of the message hook, so I'll be able to replicate that nicely.

 

The aircraft was finished in the standard camouflage scheme of Foliage Green / Earth Brown and Sky undersides. Here's a couple of images of what the aircraft looked like. Below you can see a supply canister being loaded under the port wing:

 

 

Below you can just make out the message pick-up hook under the fuselage centre-line:

 

Loading the experimental stores canisters... lots of wear around the engine cowl...

 

And finally a later image with the aircraft overall Foliage Green and white empennage, taken on Bougainville around April 1945. If you look carefully, you can see 3 aerial wires leading from the top of the antenna mast - one to the top of the rudder (as usual) and one to each wing-tip (not usual!):

 

So what are we starting with in the MPM Models kit? Well, it's pretty basic. Large gates on the moldings, honking ejector pin marks and annoying flash along the parting lines. Minimal cockpit and zero wheel-well detail...

 

 

The propeller is very basic, and the engine is the figment of some tool-maker's imagination!

 

 

The fuselage side panels bulge out (which they should not do) and some of the surface details on the wing panels is fictional, but at least I know what I'm working with.

 

First step after cleaning up the moldings was to add some basic internal detail to the insides of the fuselage side-panels, representing the aluminium extrusions and  pressed formers over which the fabric was attached. These panels were removable on the real aircraft, making maintenance of the hydraulics, the engine control push-rods and elevator/rudder cables very simple.

 

 

More coming...

Edited September 2, 2021 by Derek_B
extra info

[Ish]

I've got one in the stash and I'll be watching this one take shape. Looking good thus far!

[bigbadbadge]

This looks very interesting,  what a machine and what a sad end too.  Great start to your work,  what are you planning for the engine?

Chris

[stevehnz]

I'm keen to watch this too, I've the Special Hobby "First Blood over Rabaul" boxing, at least it comes with a better looking resin engine but I'm guessing the fuselage is based on this one, do they share the same inaccuracies as the 1/48 ones?

Steve.

[Derek_B]

@bigbadbadge Chris, the engine problem is easily solved with my "go-to" P&W Wasp R-1340 "jewellery" from Small Stuff. I have a stash of 5 of their 1/72 resin engines just waiting to test my eyesight!  There are more parts in these engines than in the rest of the model! The engine for this build already has the cylinders attached to the crank-case, need to get some photos soon.

 

@stevehnz Steve, the 1/72 SH kits are not "as bad" as the 1/48 moldings (did you see my analysis here?) but they still have some flaws, particularly being too fat in the fuselage and the wing/fuselage fillets are too large and too curved. I may be crazy, but I'm planning to address that in this build, so keep watching...

[stevehnz]

Hi Derek , thanks. Yes I did, after posting above. I'll watch your progress here with interest. Noting the Jays kit shown, I have messaged John Stone, to see if they are likely to be restocked, I'm thinking a cross kit might be in order or sell the SH one & make up the Jays one. Have you had anything to do with the HPM one at all?

Steve.

[Derek_B]

Is John out of stock? I took 3 off him about a month ago... maybe I cleared him out! You're probably aware the HPM kit is the same moldings as the Jay's kit, just different box and instructions. I helped Chris at HPM with one of his boxings, so you can see my drawings on two of the different versions of the HPM box.

[Derek_B]

As mentioned above, the cockpit detail in the MPM kit is pretty basic. There is some delightful photo-etch, but sadly it is actually a CAC Boomerang instrument panel (cleverly labelled as "Wirraway")! It's a mystery to me why MPM very carefully created this Boomerang photo-etch and then labelled it Wirraway. Did MPM ever release a Boomerang kit?? I wonder if they used the Stewart Wilson book "Wirraway, Boomerang and CA-15 In Australian Service" as a reference. It's a great book, but it does have one glaring mistake - a photo on page 45 showing the instrument panel of a crashed Boomerang captioned as "The front cockpit of a Wirraway, albeit a very bent one". I'll save that Boomerang instrument panel PE for another project. The seats offer a useful starting point (plus the two seat-belts from the PE), and the instrument panels and radios may be redeemable, but the rest of this will have to go!

 

 

So now I'll start working on some detailed "innards". I've made an internal fuselage frame from scratch. Here are the two side-frames, one side is finished (at the top), the other is still in the "jig". This is made from 0.5mm diameter styrene rod...

 

 

Then I made up a jig to hold the two sides at the correct distance apart, so I could cut and glue the cross-members. In the photo below the jig is upside down, with the two side-frames clamped in place, with and the lower fuselage cross-members already in place.

 

 

Then once all the cross-members were glued in place, I un-clamped the side frames and slid the jig out towards the nose of the framework, resulting in the completed frame shown below.

 

 

Then a quick test to see if the framework fits inside the fuselage moldings, looks good. If you look carefully at the photo below you can also see that I've sanded off the excessively large wing-root fillet. Now I need to profile it correctly to match the upper surface of the wing again...

 

 

So now we have an internal fuselage frame, some re-profiled and thinned-down seats mounted on their sliding rails, plus a scratch-built track for the hydraulic gun lift (this is NOT a Scarff-ring as many call it, that is an entirely different contraption)...

 

 

More to come...

Edited September 5, 2021 by Derek_B

[stevehnz]

8 hours ago, Derek_B said:

Is John out of stock? I took 3 off him about a month ago... maybe I cleared him out! You're probably aware the HPM kit is the same moldings as the Jay's kit, just different box and instructions. I helped Chris at HPM with one of his boxings, so you can see my drawings on two of the different versions of the HPM box.

So you were the culprit. He is waiting on more plastic components so no doubt they'll show up before too long. I didn't know what the provenance of the HPM kit was, so handy to know that. Meantime, I'm very much enjoying watching you work magic with this.

Steve.

[bigbadbadge]

Oh wow that tubular framework is phenomenal, really great work.

Chris

[Derek_B]

@stevehnz Steve, I've now added some photos of the 1/72 MPM and Jay's moldings compared with profile drawings here. The SH molding is basically identical to the MPM part.

[stevehnz]

Thanks for putting those up Derek, and to think, I could have been blissfully ignorant. I could probably live with the extra length if the rest was basically accurate, maybe.  

Steve.

[ianwau]

Marvellous modelling Derek!  That 1/72 fuse framing is a work of art!!  Well done!

[Derek_B]

And in case anyone is wondering how A20-502 could have been burned in a New Years eve bonfire in 1946 and yet is also on display at Ballarat Aviation Museum, an explanation may be needed!

 

 

The answer, of course, is that the A20-502 on display at Ballarat is not the real A20-502. It is, in fact, A20-511 which was restored and painted to represent A20-502 by Dick Hourigan and Ron Lee. This was a meticulous restoration, including all the original equipment (excluding the military radios and armament) and is a wonderful tribute to The Rocket!

 

Of interest in this photo I took back in 2013 is a bare Wirraway fuselage frame sitting in front of 511. Note how the frame is silver apart from the roll-over truss, which is painted yellow. The roll-over truss was always painted to match the external colour of the aircraft, so this frame obviously came from an overall Trainer Yellow Wirraway. Note that this is most likely not the original paint, as the frame would have been repainted for protection.

 

Edited September 4, 2021 by Derek_B

[k5054nz]

Not to be pushy Derek but...any progress with this one?

[Derek_B]

39 minutes ago, k5054nz said:

Not to be pushy Derek but...any progress with this one?

 

Still in progress, but this one is on the furthest "back burner". With a 1/72 Mustang, three 1/72 Wirraways, two 1/48 Wirraways, one 1/48 Harvard, one 1/32 Mustang, two 1/32 Harvards and one 1/32 Wirraway all on the go at the moment, I need to prioritise!! Oh, and I still need to finish the manuscript for my Wirraway book!!

[Derek_B]

Yes, this build is still in progress (but very slowly). Together with some other builds I'm working on several Pratt & Whitney R-1340 Wasp engines, and as mentioned previously, this model will benefit from one of the Small Stuff resin engines - these are just marvellous!

 

Below we see said engine, with the crank-case, reduction gear housing and oil sump splashed with XF-23 Light Blue. The detail in these 1/72 resin engines is just insane:

 

 

And again with some XF-69 NATO Black to detail the cylinders and cylinder heads:

 

 

Next I need to tidy up the paint on a couple of those cylinders, then add pushrods, spark plugs and spark leads - yes, the spark plugs are supplied as separate pieces in this engine kit!!

 

In case you're interested in Wirraway engine colours (and who isn't??), check my analysis here (top of page 3):

 

Edited October 23, 2023 by Derek_B

[2996 Victor]

Superb internals and engine work - is there any news on this one, Derek? And how's the book coming along?

 

Cheers, 

Mark