W3A Sokol Helicopter (Unusual Aircraft Collection)

A W3A Sokol ("falcon") helicopter of the Czech Air Force does a water bombing display at the 2006 Czech International Air Fair.

The Sokol was built by the Polish company PZL (short for "state aviation works"), which also made the very popular PZL-104 Wilga short takeoff and landing (STOL) aircraft.   The Sokol has received many export orders from countries like Germany, Italy, Russia, South Africa, Vietnam and South Korea.  Some are used by civilian operators and there are military versions performing duties such as search and rescue, medical evacuation, flying command and control, and even acting as a gunship with two 23mm cannon and other weapons mounted on pylons.

Sopwith Camel (World Fighter Aircraft Collection)

The Sopwith Camel was the most effective British fighter of world war one, credited with shooting down almost 1300 enemy aircraft, more than any other Allied fighter.

A saying of the time was that the Camel would give you either "A wooden cross, a red cross or a Victoria cross", meaning either a grave marker, a serious injury tended by Red Cross medical staff, or the highest British military decoration.   The saying came about because of the flying characteristics of the Camel, which were treacherous for an inexperienced pilot but advantageous for a skilled pilot.

Like most fighter aircraft of this time, the Camel had a rotary engine, which meant that the engine cylinders were arranged in a circle and then the propeller was fixed directly to the engine.   When the engine was running all of the cylinders and the propeller were spinning around at several hundred RPM.   In contrast, many World War Two aircraft usedradial engines, where the cylinders remain stationary and spin a shaft to which the propeller is fixed.

The torque of a rotary engine makes the fuselage of the aircraft rotate as a reaction to the turning of the engine.  If the pilot tries to turn the aircraft he has to fight against the torque when turning in one direction and he is helped by the torque when turning in the other direction.   So the Camel would turn right very rapidly, but only slowly to the left.   If a pilot wanted to turn 90 degrees to the left it was often quicker to turn 270 degrees to the right!

Almost all of the weight in the Camel was within the first seven feet of the aircraft and this magnified the torque effect, allowing the Camel to turn right about twice as fast as any other fighter, a considerable advantage when dogfighting but a problem when trying to fly normally.   If the pilot stalled the plane then it would immediately spin, and the Camel was known for killing pilots who entered a spin.   The Camel's maneuverability was further enhanced by another design feature which would normally be considered a flaw - it was very tail-heavy and the nose kept trying to push upwards.   It was hard work for the pilot to counteract this, but it meant that the Camel would perform loops very easily, another advantage in combat.