Tonka (also TONKA-250 and R-Stoff) is the name given to a German-designed rocket propellant first used in the Wasserfall missile,[1] and recently used by North Korea.
Its composition is approximately 50% triethylamine and 50% xylidine/T1-Kerosene, most commonly used with nitric acid or its anhydrous nitric oxide derivatives (classified as the AK-2x family in the Soviet Union) as the oxidiser; the combination is hypergolic and has a maximum practical specific impulse of approximately 2.12–2.43 km/s (216–248 s) at sea level, with the latter figure stated as a specification for the R-21 Submarine Launched Ballistic Missile, first fielded in 1963.
[6] The most globalized use of Tonka is as an igniter in many Soviet Scud missile variants and its descendants, such as the North Korean Nodong, which are principally propelled by nitric acid and kerosene (TM-185).
[7] The progenitor Scud engine, the S2.253, with a specific impulse of 2.15 km/s (219 s) at sea level,[8] popularized this ignition arrangement.
Little change was required to the engines but as this was no longer hypergolic with nitric acid, a small tank of TX was retained for ignition.