Australia Australia (1944)
Improvised Vehicle – 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.

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

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


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

Links & Resources

Australian Army Inventions File 154142, 1944

Medium Tank M4A3 (105) HVSS ‘Porcupine’
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8 Responses to Melvaine’s Mobile Pill Box

  1. Boris says:

    Really clutching as straws it seems these days ,

  2. Milos says:

    Interesting idea. Not good but interesting none the less 🙂

  3. Eric says:

    Bob Semple having a run for his money I see.

  4. Evan says:

    10/10 best tank of the war

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