WW2 Australian Prototypes

Melvaine’s Mobile Pill Box

Commonwealth of Australia (1944)
Mobile Pillbox – None Built

The ‘Mobile Pill Box’ was the brainchild of W. W. Melvaine. He lived in Brighton Boulevard, Bondi, Australia. It was one of many inventions submitted to the Army Inventions Directorate of the Australian Army in the Second World War. Many designs were submitted for all manner, shape, and size of weaponry including tanks. Although the inventors of such vehicles often had a preference for huge landships or ‘big-wheel’ designs there were also a number of smaller designs and Melvaine’s Mobile Pill Box’ is perhaps one of the more unusual Australian tank designs of the War.

Melvaine’s mobile machine gun and grenade pillbox of 1944. Photo: Author’s

On 19th January 1944, Melvaine wrote a surprisingly short letter to the Army with this suggestion. It was notable for the total lack of detail and explanation. It did not contain any ideas about why he thought his idea might be good, or better than methods or vehicles currently in use. The entirety of his letter comprised just four handwritten lines:

“Dear Sir, May I suggest the possibility of such a thing as a bulletproof mobile machine gun and grenade pill box for close up attacks on foxholes and dugouts – Yours Faithfully W.W. Melvaine”

The sentence was followed by three crudely drawn sketches of his idea which more resembled the traditional Australian thunderbox (outside toilet) than any kind of useful tank.

Possibly a sketch of the rear of this vehicle appearing to show the design open at the back. Photo: Author’s

The Design

The design was relatively simple, consisting of a small tracked platform with at least two wheels on each side powered by a small motor in the crew space. This small motor was open to the occupant. There was just enough room for a single soldier. This soldier would have to man the single forward facing machine gun from a standing position.

As well as the machine gun the soldier inside would have a box of grenades. From within this armoured-outhouse, he would most likely have had to exit through the open rear to lob a grenade. This would have meant being exposed to enemy fire from the flanks.
The height of the machine would mean it would be visible to the enemy before the soldier could see them and there is no clear indication of how it was to be steered or even how the soldier would be able to see where he was going.

There is no indication provided by Melvaine as to the prospective size of the machine which can only be estimated by the size of the soldier and no idea as to the performance he wanted or expected. Likewise other than saying ‘bulletproof’, there was no thought given to the amount of armour this design should carry.

The Official Review

This idea by Melvaine received perhaps one of the shortest assessments for an invention, and it was as blunt as it was negative, saying:

“Tanks are in use for this purpose. The proposal is crude and retrograde”.

And with that, the idea was dead.


Being disparaging about some of these invention ideas could be considered churlish. This design had, after all, the advantage of simplicity on its side, and perhaps under other circumstances might have found some kind of use. The idea though, that in 1944, this invention might somehow be suited to attacking enemy positions when tanks were available was simply incorrect and betrays a fundamental misunderstanding on the part of the author. The rather short letter, more of a note about it, perhaps indicates that this was more of a whim than any properly considered design. Nonetheless, the idea was recorded and preserved even though the concept was completely disregarded.

Front view of Melvaine’s concept. Photo: Author’s

Illustration of Melvaine’s Mobile Pill Box by Mr. C. Ryan, funded by our Patreon Campaign.


Dimensions 2.5 x 2 x 2 meters
Crew 1
Armament : Single Machine Gun and Hand-Grenades
Armor Bullet Proof


Australian Army Inventions File 154142, 1944

17 replies on “Melvaine’s Mobile Pill Box”

I liked it. It gives an example of the well-meaning (or charlatan) ideas that people bombard there governments with during war time.
Could you imagine being on the committee that would have to wade through all the crackpot ideas, just on the chance there was a good one?

I think the even harder job would have been trying to sell the Army on the few good ones you found. The Australian army had a marked contempt for basically any designs that didn’t come from either the US/UK or from within the Australian Army itself. The best example was the Owen Machine Carbine which the Army spent almost two years trying to block (despite it having been proven superior to both the Thompson and Sten) in spite of the recommendations of their fellow Army officers in Inventions Directorate. The officer in charge of the Owen case basically had to leak the story to the press in order to get the ministers in Canberra to override the Army and place an order for the guns
TE Moderator

I liked it. It gives an example of the well-meaning (or charlatan) ideas that people bombard there governments with during war time.
Could you imagine being on the committee that would have to wade through all the crackpot ideas, just on the chance there was a good one?

“Well it seemed like a good idea at the time”
So forget that this just wouldn’t work from a technical, tactical, common sense etc etc., how much concrete would be needed?
If this was used against, say a Japanese pillbox, how thick would the concrete have to be to stop fire from a machinegun?

Concrete is quite good at stopping regular bullets (ie not armour piercing ammunition), and only an inch or so would have been able to quite adequately protect the operator, against grenades or other explosives is another matter. The biggest issue for concrete as armour is the weight factor, several nations (including the British, Germans and Americans) experimented with concrete as armour and generally came to the same conclusions that the weight required to provide adequate protection was worth less than simply using armoured steel of a significantly lower thickness
TE Moderator

Was this produced before or after the public house closed for the night?
As far as civilian input goes, you can’t ignore it for the one inspired notion, but you have to wade through an awful lot of garbage. During the Kaiser War, the British Master General of the Ordnance had to set up a committee to review the public’s submissions after the Patent Office requested the services of an “expert artillerist” to deal with the mountain of ideas they did not have the expertise to evaluate. After the Zeppelin raids started AA shells were particularly popular and Ian Hogg (The Guns: 1914-1918) said that if you plowed through the Ordnance records of the time one came to the conclusion that every man, woman and child in the British Isles “had a go” at designing an AA projectile. The most favored designs seemed to have favored some form of flick out knives or weights on the ends of chains or, better yet, knives on the end of chains. The only drawback is they all required a direct it (or nearly so) and given the airframe construction of the time, if you could manage that, a common house brick would have sufficed to bring down the target without any need for all the complication.
And instead of concrete, I would have used the Plastic Protective Plating developed by the Royal Navy’s Department of Miscellaneous Weapons Development (Gerald Pawle’s The Secret War & Azriel Lorber’s Misguided Weapons). At DMWD’s offices a sample of PPP was used as a bulletin board, as it would easily take a thumb tack but stop an armor piercing bullet!
Over 10,000 vessels (mainly merchantmen but including costal forces such as MTB’s and MGB’s and landing craft) received the plating and it was produced world-wide , including in the US.
The US tested it as supplemental to armor plate on AFV’s to help resist shaped charge weapons such as the panzerfaust
“The original plan for tank protection with plastic armor was to produce HCR2-filled steel panels, small in size to reduce the area damaged by a single projectile, which could be fastened to an M4 Sherman in an emergency. To protect against the largest Panzerfaust, eight to twelve tons of plastic protection were required for an M4, while an M26 Pershing’s greater base armor meant it required only 7.1 tons of additional protection to equal an M4 with 11.7 tons of plastic protection. This was a 34% increase in weight for an M4, but only a 16% increase for an M26, and the panel for the M26’s turret was only ​10 3⁄4 inches thick compared to ​13 3⁄4 inches for the M4. New panels made of welded steel armour, half an inch thick on the sides and three-quarters of an inch thick on the faces, were designed, but their construction was incomplete at the end of World War II. As a result of increasing tank losses to shaped charge weapons, another type of panel that could enter production in only a few weeks was designed. This new type of panel used ​1 1⁄2-inch mild steel instead of armor steel, and had a two-inch plate of 21ST aluminium alloy backing the face plate for reinforcement. One set of this armor was completed and tested just after the end of World War II and was considered quite satisfactory, although less so than the panels made of armor steel”

Were I part of the committee I would have voted in favor of the idea had the inventor stated its purpose thus:
“Dear Sir, May I suggest the possibility of such a thing as a bulletproof mobile thunderbox, permitting our men to take a dump in the field, whilst protected by enemy small arms fire.
Yours Faithfully, Forest Dump”
I would have named it “Thunderbox Mobile Field fortification”, and it would have been an epic win.

Leave a Reply

Your email address will not be published. Required fields are marked *