Walter HWK 109-509

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HWK 509
HWK 109-509A on display at the
Luftwaffenmuseum
, Berlin-Gatow, Germany
Type Rocket engine
Manufacturer Hellmuth Walter Kommanditgesellschaft
First run 1943
Major applications
Bachem Ba 349

The Walter HWK 109-509 was a German liquid-fuel

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

An early Walter HWK 109-509A-1 rocket motor, believed to be one of the best preserved in existence and possibly used for instructional purposes.[1] The cockpit of the Me 163 Komet is a mockup. (Image from Shuttleworth Collection, UK)

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 the fact 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.

HWK 109-509 A-1 Rocket Engine at Steven F. Udvar-Hazy Center Virginia, USA.

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 on contact.[2] The violent combustion process resulted in the formation of water, carbon dioxide and nitrogen, and a huge amount of heat sending out a superheated stream of steam, nitrogen and air that was drawn in through the hole in the mantle of the engine, thus providing a forward thrust of approximately 17 kN (3,820 lbf).

To address the throttling issue, the new engine included

catalyst.[3] Combined with a mechanical throttle, this provided four power settings from idle to full power for climbing. In practice it was found that throttling the engine dramatically decreased its fuel economy
to the point that it did not extend the endurance of the aircraft as expected. This version was put into the Me 163B in spite of this problem.

The ultimate solution to the throttling problem was the B and C series of the engine. These engines used two combustion chambers, the original one (retroactively given

the name Hauptofen
), and a second, smaller Marschofen chamber directly beneath the main Hauptofen chamber, tuned to provide the cruise power needed for high-speed level flight, about 400 kilograms-force (3,900 N; 880 lbf). This chamber provided that power at peak efficiency, so it did not suffer from the problems found while throttling on the original models. The throttle on the original combustion chamber was removed, and throttling was instead provided by turning the main engine on and off. This new version dramatically improved cruise endurance, with overall flight times improving from eight to twelve minutes, a 50% improvement. It was also mechanically simpler as the turbopumps were no longer throttled.

The engine was an integral design with all components of the drive, with the exception of fuel tanks, locked in a cubical frame — this frame was discarded for the 109-509C dual-chamber design.

Variants

Applications

Engines on display

Specifications (509A)

Data from Jane's.[9][full citation needed]

General characteristics

  • Type: Liquid-fuelled rocket engine
  • Length:
  • Diameter:
  • Dry weight: 165.5 kg (365 lb)
  • Fuel: T-Stoff (Hydrogen peroxide) oxidizer and C-Stoff (hydrazine hydrate/alcohol mix) fuel propellants

Components

  • Pumps:

Performance

  • Thrust: 14.7 kN (3,300 lbf)
  • Burn time:
  • Thrust specific fuel consumption
    :     20 lb/hr/lbf (1800 N-s/kg)

See also

Related lists

References

Notes

  1. ^ a b "Shuttleworth Collection". www.walterwerke.co.uk. Archived from the original on 23 August 2016. Retrieved 7 October 2021.
  2. ISBN 3-8289-0294-4
    , 1998 page 220, German
  3. ISBN 3-8289-0294-4
    , 1998 Seite 221+222
  4. ^ "Walter HWK 509A Rocket". National Museum of the United States Air Force™. 21 April 2015. Archived from the original on 18 May 2017. Retrieved 7 October 2021.
  5. ^ "Walter HWK 509A Rocket". National Museum of the United States Air Force™. Retrieved 2021-10-07.
  6. ^ "Walter HWK 509B-1 Rocket". National Museum of the United States Air Force™. Retrieved 2021-10-07.
  7. ^ "RAF Museum, Cosford". www.walterwerke.co.uk. Archived from the original on 4 November 2013. Retrieved 7 October 2021.
  8. ^ Komet engine at the Cosmosphere
  9. ^ Jane's 1989. p.285.

Bibliography

External links

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