(first run in 1943)

The Walter HWK 109-509 was a rocket motor designed and made in Germany during World War 2. For its size and weight it created enormous power. It was used in several experimental German aircraft and in the Messerschmitt Me163 interceptor fighter.

During World War 2 the firm of Helmut Walter made several rocket packs that were attached to aircraft to give them additional thrust during take off. This experience helped the company develop this much more complex rocket motor.

This motor was fuelled by two highly volatile chemical solutions which react explosively when combined. The front part of the motor comprises the pumps for the chemicals and the rear part is the chamber in which they are combined. The resulting violent combustion generated up to 14.7kN (3,300lb) of thrust.

The Messerchmitt Me163B interceptor fighter was built around this rocket motor. It gave the aircraft a tremendous climb rate and a speed well over 100mph faster than opposing fighters. This made it virtually invulnerable during powered flight.

However this aircraft carried only enough fuel for about eight minutes powered flight after which it had to glide back to base when it was very vulnerable. The volatile fuel also made this a very dangerous aircraft to fly and most were lost during or after landing.

Me163Bs began flying operationally in July 1944 but their limitations and small numbers meant they had no impact on the outcome of the war.