The North Atlantic has some of the worst and most unpredictable weather in the world. The biggest problem facing the airlines who wanted to fly commercially over the lucrative routes between the United States and Europe was the vehicle. How could one aircraft carry passengers, freight and enough fuel to fly over 2,000 miles in such terrible conditions?
It was generally agreed in 1924 that the aeroplane would never be a suitable vehicle for carrying passengers across the Atlantic and that airships would operate all the long distance routes of the future. In the summer of 1936, Germany began the first commercially viable service across the Atlantic using airships. These lighter than air balloons filled with highly flammable hydrogen gas were the slow moving, luxury liners of the sky.
On the 6th May, 1937, the German airship the Hindenberg, caught fire while mooring at New Jersey. The airship was completely destroyed and thirty-six people died. The whole disaster was recorded in vivid detail by a Pathe news film cameraman and reporter. The newsreel was shown in cinemas around the world. The Graf Zeppelin, was immediately withdrawn from the service and there were no more airships on the Atlantic.
Land planes were inappropriate as they were heavy and required hard runways–and there were very few of them before World War II. On the other hand, flying boats had many advantages, primarily that there were always landing places for even the heaviest flying boat and almost all the great cities of the world were near the sea or large waterways—few had suitable runways.
However, there were some problems with flying boats—they needed large amounts of fuel just to get itself off the water yet, once airborne they needed only a relatively small amount to keep it at a cruising speed. How do you get the aircraft into the air without using too much fuel? There were three initial answers to this question:
1. Catapults: This would simply fling a seaplane from the deck of a depot ship using a compressed air catapult. Though this was successfully tried in 1937, it could never be used for passenger traffic because of the high gravity forces.
2. The Mayo Composite: Another way to get an aircraft into the air without using fuel is on the back of another aircraft “piggy-back” style. On the 20th July, 1938, the Short-Mayo Composite (designed by Major R.M. Mayo of Imperial Airways) took off from Foynes. The mother aircraft “Maia”, carried the smaller “Mercury” well out to sea before they separated. After separation the Mercury flew on to Montreal and the Maia returned to Foynes.
But this would have been a dangerous and alarming way to handle passengers, and, as with in-flight refuelling, only mail could be carried. In 1939 the British Air ministry rejected the project.
3. In-Flight Refueling: If an aircraft takes off under its own power, it uses a lot of its fuel just to get airborne. So, if it can refuel after takeoff, it can fly much further. The only way to refuel in the air, of course, is from a flying petrol tanker. And this is exactly what British Imperial Airways tried in 1939.
Two flying boats—Cabot and Caribou—made eight round trips from Foynes to Newfoundland. They were refueled in the air by a converted Harrow bomber, which took off from the grass runway at Rineanna—which is now Shannon Airport.
A cable from the tanker was shot to the flying boat using a rocket-propelled harpoon. This was attached to a hose that was then locked into the flying boat’s fuel tank; the tanker flew over the flying boat and the fuel flowed by gravity.
In the end, in July 1936, Pan American Airways signed a contract with Boeing for the first practical transatlantic passenger aircraft—the B.314 flying boat.