Dinky Aircraft – Forgotten Greats

Preserving the Memory

Carrying the Mail

Sometimes, a toy manufacturer will create a model for which, in later years, we are truly grateful, because it preserves the memory of a fascinating but otherwise long-forgotten subject. Most makers manage to (unwittingly) do this at some point! In the Dinky Aircraft range, there are several such models, but none better than that of a rather unique craft designed to deliver the mail.

One of the most attractive commercial opportunities for early airlines was the delivery of Transatlantic airmail. Even the fastest mail ships took a week or so to make the journey, so the advent of an air service that might make the trip in a day offered a huge advantage, at least as far as urgent mail was concerned.

However, in the 1930s, transatlantic air crossings were barely feasible owing to the limited range and power of the available aircraft. Mail is a relatively dense and heavy cargo compared to passengers, so even where passenger services were viable, mail delivery was more challenging. Increasing the range of aircraft by storing more fuel was possible, but this made the aircraft heavier and often meant using up the very cargo space needed for the mail.

R.H.Mayo, the chief engineer of Imperial Airways, came up with a possible solution as early as 1932. Because it took more energy to get an aircraft airborne than it did to maintain level flight, Mayo’s approach was to use two aircraft. The first aircraft would carry the mail, while the second would launch the first into the air by carrying it on its back, and then release it for the onward flight, before returning to base. It was believed that the saving on fuel consumption during take-off would give the mail carrier the necessary range to cross the ocean.

The Mayo Composite, consisting of the Maia (bottom) and the Mercury (top). Note the trolley used to hold and move the Maia on land.

The most promising type of aircraft for transatlantic flights at that time were the flying boats manufactured by Short Brothers, partly due to their ability to land at shore stations without requiring runways or other infrastructure. To carry the mail, a new medium-sized floatplane was designed by Shorts, the S.20 Mercury (named after the Greek messenger god). The Mercury had a very respectable range of 3,900 miles and a cruising speed of 195mph. In fact, if extra fuel was stored in the floats and without any cargo, it could attain a range of over 6,000 miles – as demonstrated by a record-breaking 1938 flight from Dundee to the Orange River in South Africa.

To carry the Mercury, Shorts built a new large flying boat based on the ‘C’ class then in use by Imperial Airways, but with a strengthened and widened fuselage, and greater wing area for improved lift. It was much larger and heavier than the Mercury, with a slightly slower speed and a much more conservative range of 850 miles. The aircraft was named the S.21 Maia (named, appropriately for a mother-ship, after the mother of Mercury). The two aircraft together were known as the Mayo Composite.

A Churchman’s cigarette card showing the composite taking off. The artist has not found it easy to capture the hull shape of the Maia.

In operation, the Mercury was attached to a pylon on the back of the Maia. During take-off the Maia was lightly fuelled to keep weight down, and both aircraft used their engines, though only the control surfaces on the Maia were operable. The Maia then climbed. The Mercury remained fixed to the Maia until both pilots independently released the pylon attachment, and at a speed of roughly 150mph the Mercury used its greater lift to simply rise off the pylon and into independent flight. The Maia then returned to base.

A beautiful cutaway diagram of the Mayo Composite (Wonders of World Aviation, part 1)

The Mercury made its maiden flight in 1937, and after extensive testing, in July 1938, the Maia successfully launched it on its first transatlantic flight. Further development stalled however, with the advent of World War 2. Only the one example of Maia and Mercury were built, and the concept was never put into service. Maia was destroyed by the Luftwaffe during WW2, and the development of more powerful aircraft during the war resolved the problem of transatlantic travel without requiring the complicated composite approach. The simultaneous development of inflight refuelling, which was successfully trialled in 1939, was another nail in the coffin.

The Dinky Mayo

Dinky 63 Mayo Composite

Year first produced:1939

L126xW160xH42, Metal 124g, Scale 1:210, Features: 1

The first thing to observe about the Dinky model of the Mayo Composite is that although the two aircraft are separate models, they are permanently fixed together by a tinplate representation of the real-life pylon. So, rather frustratingly, it isn’t possible to recreate the take-off and separation of Maia and Mercury.

Let’s look at the Maia first. Here, Dinky took a shortcut. Rather than creating a new model, they reused their 60r Empire Flying Boat (the Short ‘C’ class, of which the Maia was a derivation), which inevitably means that although the model looks broadly correct, it is not entirely accurate.

The main components are diecast metal. The main wing, complete with four engines, is a single casting fixed onto the casting of the fuselage and tail. Under the wing are attached the two floats, and tinplate propellers are pinned in place on the engines, so that they can rotate freely. The fuselage is a hollow casting open at the bottom, and into it is fitted a roller secured into the sides of the fuselage on a metal pin with crimped ends. As far as I can tell, the roller on my model is made out of bakelite, or some such early material. I assume that the purpose of the roller is to enable one to push the aircraft along a flat surface more easily, but hmm, it seems a trifle redundant…

The underside of the Maia.

On the underside of the wings are the following marks


As with the actual Maia, the aircraft is finished in an overall silver colour, carries the registration G-AHDK on the upper wing and the name MAIA on either side of the forward hull. However, unlike Maia, the registration number is not repeated on the lower wing or the rear fuselage.

Turning now to the Mercury, we find that it is made as a single casting. As with the Maia, four propellers are pinned to the engines and can spin freely; underneath are attached the two floats. These are quite large compared to those on the Maia, since the Mercury relies on them for buoyancy while the Maia requires them only for stability.

The marks under the wings say


The Mercury is also finished in silver, named on the front of the fuselage, and marked with the correct historical registration G-ADHJ (but only on the upper wing surface).

The Composite in its box.

The model was supplied in a cardboard box, which is closely tailored to it. The lid lifts off to reveal the model, which fits neatly into a cut-out within the thick cardboard insert in the base. Seen together the models are, like the original aircraft, an impressive and unusual sight.

On the top of the box is a brief description of the aircraft.

Metal Fatigue?

The observant reader will have noticed that my model is far from perfect. This is not unusual for models from the pre-war era, since they are by now over 80 years old, and will have sustained many knocks. However, there is an additional factor which is worth mentioning, commonly called ‘metal fatigue’.

Before addressing the latter, let’s first dispose of the other damage in evidence. The box should be blue, as shown on the insert, but has faded somewhat, and has also warped slightly. Not surprising for a cardboard box made in 1940!

The previous owner of this model admitted to dropping it, snapping off the left wingtip of the Maia. It has been reattached but not retouched, so as to keep the model ‘honest’ and not disguise the fracture.

The broken wing tip

There is also some curious bubbling to the paintwork on the Maia’s upper wing. Maybe there has been some retouching of the paint, which failed to take properly?

The eagle-eyed will have noted that both Maia and Mercury have square holes in the top of the fuselage. These were intentionally made at the time of manufacture for a purpose which I will reveal in a future story…

The mysterious square holes.

However, perhaps the most obvious damage to the model is to be seen at the front of the Maia, where some cracking is apparent. This is frequently seen on the diecast elements of pre-war Dinky models, and is often, and mistakenly, called metal fatigue. Actually, metal fatigue is tearing caused by repeated flexing and stressing of metal, which is not what has happened to the front of our casting.

The forward fuselage of the Maia shows an area of crazing.

A better description of the cracking is metal corrosion (sometimes referred to as metal rot). The metal used in creating the Dinky aircraft is mazak, an alloy of zinc with minor amounts of other metals. In the correct proportions and without impurities, it is a stable mix. If the proportions are altered or impurities introduced, however, it can become unstable and over time chemical reactions begin to break down the metal. The first sign is usually cracking and bulging, and this is what we see here. Unfortunately, the corrosion cannot be reversed and eventually the model will simply crumble into dust.

The impurities may have been introduced by the uncontrolled (and unwise) addition of waste materials from the Dinky factory, such as tin, lead and solder, into the alloy mixture. Some people believe that these were quite literally the sweepings from the factory floor, though that seems unlikely to me. A more obvious motivation for introducing other materials into the alloy would have been the shortages associated with wartime, when metals were in scarce supply and needed for war production, and short-term expedients to bulk out the metal might have been found necessary to keep production moving. Models produced during the 1939-41 period are, indeed, particularly susceptible to the problem. That these impurities might cause corrosion in the future might have seemed a distant concern; and the blame for the adulteration might have lain with Dinky or their suppliers.


Although the Mayo Composite concept was not pursued, there is a modern example of piggy-backing an aircraft. The NASA Space Shuttle was used to transport astronauts and equipment to orbiting space stations, which it did by blasting off vertically from the Earth for the outward journey and returning by entering the atmosphere and then simply gliding back to land. During the development and testing of the shuttle within the Earth’s atmosphere, when NASA wished to test the shuttle’s ability to land without having to send it off into orbit, it was carried into the air on the back of a modified Boeing 747 airliner, and released to glide back to the ground.

This image has an empty alt attribute; its file name is mayo-shuttle.jpg
A modern composite – the NASA Shuttle and the carrier aircraft.

The Mayo Composite is a strange and rather wonderful model, impressive to look at but perhaps more importantly bound to raise questions in the mind of the modern observer. Could such an aircraft have existed? What was it for? What happened to it? I’m really glad that Dinky chose to make it!


Flying boats were popular during the 1930s and Dinky reflected this by producing a clutch of models. We have already seen how the Maia was a repurposed 60r Empire Flying Boat, but the same casting was also used for the fictitious 60x Atlantic Flying Boat which was produced for a short time in a variety of colours and with a selection of imagined names on the hull.

Other flying boats of the 1930s modelled by Dinky include:

  • 60h Short S.19 Singapore Flying Boat
  • 60w Pan American Airways Clipper III (a Sikorski S-42-B).

Author: hexeres

Amateur photographer, military toy enthusiast, footslogger, dog lover, history buff and ebay trader to mention just a few...

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