Development of the singe-shot, disposable grenade launcher for Soviet army, which fired incendiary, thermobaric / FAE (Fuel-Air Explosive) or smoke rockets was initiated in 1984. The resulting weapon, known as "Schmel" (bumblebee) was adopted by Soviet army in 1988 in three versions - RPO-A with thermobaric / FAE warhead, RPO-Z with incendiary warhead and RPO-D with smoke warhead. Since the weapon is officially classified as flamethrower, per Soviet / Russian TOE it is used by Chemical troops (regardless of actual version), and usually is not issued to ordinary infantry. It is also in limited use by various Special Operations forces, including Russian Internal Affairs Ministry troops. The RPO-A version is considered as main in the whole line-up and is still in production for Russian army and export.
The RPO-A is a single-shot recoilless weapon of somewhat unusual construction. It has a fiberglass smoothbore barrel which is factory pre-loaded with a round of ammunition, which, in turn, consists of a missile with warhead and tail fins, and propelling charge. Upon firing, the propelling charge, which is loaded into separate case, is fired; it stays in the barrel while powder gases accelerate the missile; when missile has left the barrel, the propelling charge is expelled to the rear by the residual pressure, and falls to the ground at several meters behind the weapon. Obviously, this weapon creates a dangerous back-blast when fired. The basic controls include dual folding grips and rifle-type trigger with manual safety. Rear sight is of diopter type, with several apertures for different ranges. It is installed on the folding base; front sight is fixed. The missile is nothing more than a thin-walled container loaded with Fuel-Air Explosive (RPO-A), smoke composition (RPO-D) or Incendiary composition (RPO-Z), with four folding fins at the base. The blast effect of the thermobaric / FAE RPO-A warhead, which contains about 2.2 kg of Fuel-Air Explosive is roughly equivalent to the blast effect of the 107mm / 4" HE artillery shell. Upon explosion, RPO-A warhead generates the cloud of high-temperature flame (blast) which is about 6-7 meters in diameter (blast radius 3 meters or more). The blast cloud lasts as long as 0.4seconds, thus allowing for significant incendiary effect in addition to the massive pressure wave (typical HE explosion lasts much shorter).