Type 4 Incendiary Rocket (RoSa)

The Roketto Yon-shiki Shō-san-dan (ロケット四式焼霰弾), sometimes just RoSa-dan (ロサ弾) where anti-aircraft rockets used by the Imperial Japanese Navy during the World War II, combining incendiary shrapnel elements.

This rocket was deployed on the 12 Senchi 28 Rensō Funshinhō (十二糎二八連装噴進砲), a specially built rocket launcher, and equipped on certain Japanese aircraft carriers and battleships.

The rocket is designated with the English borrowing "rocketto", but stays more commonly classified as a "shell" (弾), borrowing partially the technology used by the Type 3 anti-aircraft shell "San Shiki".

The rockets were intended to put up a barrage of flame, by being notably equipped on a 28 rack rocket-launcher, through which any aircraft attempting to attack would have to navigate. However, much like the sanshiki shells, these rockets were not very effective, lacking in effect radius among other things.

Specifications


These rockets were 12 cm in diameter for 73 cm long, and weighed 47 kg. Similar to the "San Shiki", these rockets were made:
 * 24 incendiary charges, that, once the rocket has exploded, would ignite and form long flames,
 * Two explosive charges of 0.5 kg, used to create a dispersion cone of 40 ° and 30 m in diameter, to create the barrier wall,
 * A fuze, to adjust the triggering altitude of the explosive charge, and being adjustable to settings of 1000 m or 1500 m,
 * 6 rocket engines and their fuel, for propulsion, providing a maximal range of 4800 m.
 * The engines were arranged to provide rotational motion, stabilizing the rocket in flight.
 * They used "Special DT6" as fuel, a smokeless powder in solid tubes of 3.4 kg form, composed of 30% Nitroglycerin, 60% Nitrocellulose, 3% centralite (diethyl-diphenyl urea), and 7% mononitro naphthaline.

These rockets were deployed on a 28 tubes capacity rocket launcher, each rack having a length of 1 m, and linked to the ship's anti-aircraft fire control system. The rockets were fired in pairs, with the ability to fire all 14 salvos in just 10 s, the rockets reaching a speed of 200 m/s. The rockets had a maximum range of 4.8 km, with a maximum altitude of 2.6 km.