The Walter HWK 109-500 was a

liquid-fuelled rocket engine A liquid-propellant rocket or liquid rocket utilizes a rocket engine that uses liquid rocket propellant, liquid propellants. Liquids are desirable because they have a reasonably high density and high Specific impulse, specific impulse (''I''sp). T ...

developed by Walter in

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

during the

Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposi ...

Description

The 109-500 is a self-contained, modular

monopropellant Monopropellants are propellants consisting of chemicals that release energy through exothermic chemical decomposition. The molecular bond energy of the monopropellant is released usually through use of a catalyst. This can be contrasted with bipro ...

''Starthilfe'' (take-off assist) engine in a pod, able to produce

thrust Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that sys ...

for thirty seconds. After the fuel was expended, the pod was jettisoned and it returned to earth by parachute, with the parachute packed externally, onto the blunt forward end of the pod. The

T-Stoff T-Stoff (; 'substance T') was a stabilised high test peroxide used in Germany during World War II. T-Stoff was specified to contain 80% (occasionally 85%) hydrogen peroxide (H2O2), remainder water, with traces (<0.1%) of stabilisers. Stabilisers ...

monopropellant, stored in the large spherical tank within the ''Starthilfe'' module's forward end, needed to react with a

catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

to provide the boosting thrust for an aircraft on takeoff - this

Z-Stoff Z-Stoff (, "substance Z") was a name for calcium permanganate or sodium permanganate mixed in water. It was normally used as a catalyst for T-Stoff ( high-test peroxide) in military rocket programs by Nazi Germany during World War II. Z-Stoff was ...

sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...

-based, alkaline permanganate-compound (in an aqueous solution) catalyst was provided in a small tank above the reaction chamber just forward of the exhaust nozzle, with compressed air from a network of five pressure tanks driving the monopropellant and catalyst together through the reaction chamber, which featured an internal, fixed helical "swirl baffle" to lengthen the period of time the monopropellant and catalyst were in contact for a more complete catalytic reaction within it, before the reacted T-Stoff exhaust exited the nozzle. It entered service in 1942, and some 6,000 were built, by Heinkel. It was "used extensively on a wide range of aircraft", especially the potentially underpowered (when heavily laden with external ordnance)

Jumo 004 The Junkers Jumo 004 was the world's first production turbojet engine in operational use, and the first successful axial compressor turbojet engine. Some 8,000 units were manufactured by Junkers in Germany late in World War II, powering the Mess ...

-engined

Arado Ar 234 The Arado Ar 234 ''Blitz'' (English: lightning) is a jet-powered bomber designed and produced by the German aircraft manufacturer Arado. It was the world's first operational turbojet-powered bomber, seeing service during the latter half of the ...

B, with two of the units uniquely displayed as mounted operationally on the NASM's sole surviving, restored Ar 234B.

Applications

Blohm & Voss BV 138 The Blohm & Voss BV 138 ''Seedrache'' (Sea Dragon), but nicknamed ''Der Fliegende Holzschuh'' ("flying clog",Nowarra 1997, original German title of the Schiffer book. from the side-view shape of its fuselage, as well as a play on the title of t ...

Junkers Ju 88 The Junkers Ju 88 is a German World War II ''Luftwaffe'' twin-engined multirole combat aircraft. Junkers Aircraft and Motor Works (JFM) designed the plane in the mid-1930s as a so-called '' Schnellbomber'' ("fast bomber") that would be too fast ...

* Heinkel He 111 *

Messerschmitt Me 321 The Messerschmitt Me 321 ''Gigant'' was a large German cargo glider developed and used during World War II. Intended to support large scale invasions, the Me 321 saw very limited use due to the low availability of suitable tug aircraft, high v ...

Messerschmitt Me 323 The Messerschmitt Me 323 ''Gigant'' ("Giant") was a German military transport aircraft of World War II. It was a powered variant of the Me 321 military glider and was the largest land-based transport aircraft to fly during the war. A total of 21 ...

Specifications

Notes

External links

*
British 'Walterwerke' Reference Page on HWK 109-500 ''Starthilfe'' RATO Unit

Polish Aviation Museum online infopage on the uprated, experimental HWK 109-501 RATO booster
{{Aeroengine-specs Aircraft rocket engines 109-500 JATO Rocket engines using cold cycle hydrogen peroxide propellant

Description

Applications

Specifications

See also

Notes

External links