A look back at airpower history

As World War I progressed, the potential of air power began to be realized as more and larger bomber aircraft began to strike deeper and deeper into enemy territory. The Russians, Italians and Germans concentrated on large, strategic bombers while the English and French focused their efforts on smaller, lighter bombers for strikes against rail yards and what today would be called tactical targets.

With the rapid development of German fighter aircraft and anti-bomber tactics, the formations of Allied light bombers began to suffer heavy losses. Allied single engine fighters began to escort the bombers, but the bombers had a longer range and the Allies were faced with a dilemma they would face again in World War II – how to provide long range fighter escort for the bombers.

While seeking a solution, the French Aviation Militarie turned to a newly developed reconnaissance aircraft, the Caudron R.11, developed from the earlier Caudron R. IV. The R.11 was also initially intended as a reconnaissance plane, but it was a refined design and the Aviation Militarie decided to see if it could be used as a escort fighter for their new Breuget 14 bombers.

The R.11 was a biplane powered by two powerful 235 horsepower Hispano-Suiza 8Beb engines housed in streamlined nacelles, a large area tail for added stability and huge fixed landing gear. The fuselage was long and slender, much more streamlined than most aircraft of the period, resembling a stretched zeppelin. Overall it was huge for a fighter, with a loaded weigh of 4,700 pounds, a wingspan of 60 feet and a length of 36 feet, compared to a SPAD fighter’s weight of 1900 pounds, wing span of 26 feet and length of 20 feet.

The R. 11’s crew of three consisted of a pilot in a mid-mounted cockpit between the top and bottom wing, a rear gunner behind him and a nose gunner in the extreme forward of the aircraft.

The rear gunner could also use a downward facing 7.62 mm Lewis machine guns in the belly of the aircraft, a gun that eliminated a critical blind spot.

In the addition to the belly stinger, the R. 11 carried four more 7.62 mm machine guns, two each in a nose position and a dorsal position.

These guns were mounted in pairs in ring mounted that allowed rapid traverse and a wide field of fire, and had a frame built around them to physically keep the gunner from hitting his own aircraft in the heat of combat.

Since two 7.62 machine guns were the standard armament for World War I fighters, when German fighters attacked the Caudrons, they were facing fire power of equal strength and range but with an even greater rate of fire, since the guns in the Caudrons did not have their rate of fire reduced to fire through a propeller, like fighters did.

In addition to its firepower, the Caudrons were fast – as fast as a Fokker D. VII – and were easy to handle, if not exactly maneuvrable. They had long range, a maximum endurance of 3 hours, and could reach 20,000 feet. As escorts, they roamed around the bombers like sheep dogs, breaking up formations of German fighters as they prepared to attack the bomber formations.

The R.11 was very successful and early summer of 1918 was in active service over the Western Front. An improved version, the R. XIV, with 300 horsepower Hispano-Suiza engines and a 37 millimetre Hotchkiss cannon on a flexible mounting in the nose, was under development when the war ended.

Three hundred seventy R. 11s were delivered to six Aviation Militarie squadrons before the war ended, though 1,000 were initially ordered. The end of the conflict signalled the end of production for the R.11, though it continued to serve until 1922.

The R. 11 holds the distinction of being the last French production aircraft of World War One.

The success of the R. 11 as a bomber escort led air forces to the mistaken conclusion that it was possible to escort long range bombers with equally large but heavily armed escort fighters. This failed to consider that fighter armament was increasing – indeed, one version of the SPAD had a 37 mm forward firing cannon – and that flexible armament was size limited.

Between World War I and World War II there were several attempts to build large, heavily armed multi-engine escort fighters, and at the beginning of the war the Germans tried to escort their Battle of Britain bomber formations with heavily armed, twin-engine Messerschmitt BF-110s. This failed miserably as the BF-110s were savaged by more maneuverable and relatively heavily armed Hawker Hurricanes and Supermarine Spitfires.

The Eighth Air Force tried a similar concept with a modified B-17,  the YB-40, loaded with extra .50 calibre machine guns, but it too failed. The secret to the long range bomber escort proved not to be a cumbersome and heavily armed bomber type aircraft but rather aerodynamically efficient, long-range, single-engine fighters like the P-51 Mustang.

(For questions or comments, contact Dr. Michel at  marshall.michel@spangdahlem.af.mil.)