Aviation technology took a large step forward in the early to mid 1920s with the emergence of reliable, lightweight, powerful, air-cooled radial engines. These engines, with the cylinders arranged like spokes from the hub of a wheel, offered such significant improvements over the liquid cooled engines of the day in terms of reliability, endurance, and power-to-weight ratios that it began to occur to certain designers and aviators that whole new thresholds of long-distance flight were becoming possible(1).

It was the 1920s, and as the sour aftertaste of WWI faded, euphoria on all fronts began to take over. It was the kind of era where an American hotel tycoon named Raymond Orteig could put up a $25,000 prize for the first non-stop flight between New York and Paris. All sorts of aviation luminaries started to get ideas...

Many of these individuals were already well-known (such as ex WWI ace Charles Nungesser), and could get their foot in the door of investors and come away with lavish funding for the project.

One, however, could not have been much more obscure. Charles Lindbergh had been a U.S. Army aviator too late to see service in the Great War. He'd knocked around, done some barnstorming, come close to getting himself killed many times flying airmail. He had enough on the ball to be able to calculate exactly what it would take to claim the Orteig prize. He started with the fuel consumption numbers for the new radials, and worked from there...

Then he had to try and round up some money. This was an epic adventure all its own...but beyond the scope of this writeup.

Only then could he contact aircraft manufacturers and ask them if they'd make an airplane for him. A batch of telegrams went forth.

And the silence was deafening. His first couple of choices, such as Bellanca, ignored him as a crackpot.

Only the Ryan corporation of San Diego, California sounded interested. They had just introduced a new high-wing monoplane designed for airmail flying, the Ryan M-1. When they got Lindbergh's telegram, their engineers pondered a bit, and decided that they could extend the wings a couple of feet, add a whole lot of fuel tankage, and meet Lindbergh's specification. They replied to the telegram, and a meeting was arranged.

The resulting airplane, built in San Diego, was dubbed "Spirit of St. Louis" in honor of some financial supporters Lindbergh had there. In configuration, it was a high-wing, strut-braced monoplane with fixed undercarriage. The structure was welded steel tubing, fabric covered except for the forward fuselage area which was coverd with the characteristic spin-polished sheet aluminum, on which the famous logo was hand painted.(2) All space that would normally have been used for passenger or payload carriage was given over to fuel. This included two large tanks in the wings and a humongous tank occupying the entire fuselage behind the engine. Lindbergh was left with only a tiny cockpit with a wicker seat, and no forward view whatsoever. A tiny periscope was put in, but had to have been next to useless...Lindbergh had to stick his head out the side windows in order to land the plane. Which he did, to a tumultuous Paris welcome, after 33 + hours of flying, most of it over-water, dead-reckoning navigation. He was a hell of a pilot.

Notes

1. It is often forgotten that the very first non-stop transatlantic flight took place in 1919, when 2 ex RFC fliers flew their war-surplus Vickers Vimy bomber from Newfoundland to a nose-down landing in an Irish bog. Lindbergh's flight was actually the 13th crossing of the Atlantic by air, and the 5th non-stop crossing. Lindbergh's achievement was to be the first to fly between NYC and Paris, and the first to cross the Atlantic solo.

2. Other stats:
Engine: one 237 hp Wright J-5C "Whirlwind" nine-cylinder radial engine, driving a 2-bladed Metal propeller. Wingspan: 46 feet (14.2 m)
Length: 27 feet, 8 in. (8.43 m)
Gross weight: 5,250 lbs. (2,381 kg)
Max speed: 124 mph (200 km/h)
Range: 4,650 miles (7,483 km)

3. Thanks to noder Transitional Man, who corrected me on the point of the French Ace competing to be first over the Atlantic non-stop. This was not Raoul Lufbery, as originally written. Lufbery died in combat the last year of the war. Nungesser was to depart on his transatlantic attempt two weeks before Lindbergh, but he, his aircraft (named L'Oiseau Blanc), and his navigator disappeared without trace.

References: History Of Aviation - John W.R. Taylor and Kenneth Munson, editors, Crown Publishers, Inc., 2nd ed 1978 ISBN 0 7064 0241 3
Jane's Encyclopedia of Aviation, Michael J.H. Taylor, editor, Janes Publishing, Ltd., 1989 ed. ISBN 0 517 69186 8