Walter HWK 109-509

The Walter HWK 109-509 was a German liquid-fuel bipropellant rocket engine that powered the Messerschmitt Me 163 Komet and Bachem Ba 349 aircraft. It was produced by Hellmuth Walter Kommanditgesellschaft (HWK) commencing in 1943, with licensed production by the Heinkel firm's facilities in Jenbach, Austria.

Design and development

Early versions of the Me 163 had been powered by an earlier design running on a "cold engine" fueled with Z-Stoff. This fuel tended to clog the jets in the combustion chamber, causing fluctuations in power and potentially explosions. Worse, however, was that the engine could not be throttled, and when the aircraft leveled off after its climb to altitude it quickly accelerated to speeds that caused serious compressibility issues. The RLM demanded that a version be developed with a throttle.

During this period Walter had also been working with a new fuel known as C-Stoff that gave off significant heat and was thus known as the "hot engine". C-Stoff was a mix of 30% hydrazine hydrate, 57% methanol, and 13% water, with a small amount of potassium-copper-cyanide. The oxidizer, known as T-Stoff, consisted of an 80%-concentration hydrogen peroxide-based formulation. The two reacted violently

Variants

509 A-0: Pre-production model, manufactured from May 1943. The thrust of this engine was regulated between 300 kp (2.9 kN) and 1500 kp (14.7 kN).

509 A-1: The first series production engine was used in the Messerschmitt Me 163 B from August 1944. The thrust here was adjustable between 100 kp (1 kN) and 1600 kp (15.7 kN).

509 A-2: Version for the Messerschmitt Me 163B-1a. Weighing only 100 kg complete, this engine consisted of two main assemblies, the roughly-cubical shape framed forward assembly comprising the turbine housing, the fuel pumps geared to the turbine shaft, the control box, a pressure-reducing valve and the electric starter motor, with the aft assembly made up of the combustion chamber, connected to the fore unit by a cylindrical "thrust-tube" containing pipes which carried fuel to the combustion chamber's individual injector jets. The thrust was adjustable between 200 kp (2 kN) and a maximum of 1700 kp (16.7 kN).[4]Walter HWK 509B-1 USAF.jpg ]]

509 B-1: Increased performance version of the 509 A-1. This engine was the initial version to feature the twin Hauptofen main chamber above, and lower thrust Marschofen cruise chamber design directly below the main chamber, with an additional thrust of 300 kp (2.9 kN). This auxiliary chamber proved necessary due to the actual T-Stoff oxidizer consumption of the main unit, at nearly 5 kg/s, exceeding estimates by 100%. Thrust from main chamber adjustable between 100 kp (1 kN) and 2000 kp (19.6 kN). Fully restored examples of both the Me 163B's single-chamber rocket motor,[5] as well as the only known example — stated as the third prototype example — in the United States of the experimental twin-chamber Walter "509B" rocket motor,[6] are each on display in front, one each to either side of the NMUSAF's restored Me 163B, bearing Werknummer (serial number) 191 095 on its vertical fin.

509 C-1: Dual-chamber motor like the B-series, based on the uprated version of the 509 A-2, but having a main Hauptofen chamber with a differing forward shape[7] from that on the 509B, while also discarding the open-structure cubical frame for lighter weight. The main combustion chamber gave between 400 kp (3.9 kN) and 2000 kp (19.6 kN), the Marschofen auxiliary chamber 400 kp (3.9 kN). To be used in the Me 263 (Ju 248). One surviving example on museum display at the Royal Air Force Museum Cosford.

509 D-1: Variant of the 509 C-1 for use in the improved B-series airframes of the Bachem Ba 349 Natter. Engine designed to be recovered by parachute, along with the entire rear section with empennage.

509 S-2 A completely revised lightened version for use as a permanently installed booster rocket on the Messerschmitt Me 262 Heimatschützer IV home defence interceptor.

HWK RII-211 - Company designation for prototype engines of the 509A-2 series

engine type	Rocket engine
manufacturer	Hellmuth Walter Kommanditgesellschaft
first run	1943
major applications	Messerschmitt Me 163 Bachem Ba 349

Design and development

Variants

Applications

Engines on display

Specifications (509A)

See also

External links

References