KTRV advances Grom air-to-surface missile acceptance trials

Russia's Tactical Missiles Corporation (KTRV) plans to complete acceptance trials of a guided modular missile by September 2018. Batch production is likely to begin in November 2018, IHS Jane’s Missiles & Rockets reported quoting a KTRV presentation.

Grom Missile Russia KTRV 001 A Grom-E1 air-to-surface missile showcased at MAKS 2017

According to the design, the air weapon comprises a warhead module, a planning and control module, a power plant module or an additional warhead module, a steering drive module, and automatic jam-proof satellite navigation equipment. The missile is 4192 mm long and the hull diameter is 310 mm. The weapon has five compartments. The first two accommodate the main warhead and planning and control modules. They carry a set of contact sensors, the main warhead, connector and the carrying module of the planning and control system, as well as the front crossbeam. The first and second compartments are 2350 mm long. The third 390mm-long compartment carries onboard equipment. The forth 1130mm-long compartment accommodates either the power plant module or an additional warhead, as well as satellite navigation antennas and the back crossbeam. The fifth 322mm-long compartment holds the steering drive module, engine nozzles and fin locks.

The weapon has three options. The first one (9-A-7759 with 9-Zh1-7759 combat tool) is equipped with warhead and power plant modules. The release weight is 594 kg and the payload is 315 kg. Its combat power exceeds unguided high-explosive fragmentation OFAB-250-270 air bomb 1.8 times. The maximum range is 120 km, maximum flight time is 400 seconds. Delay range is 0 to 170 msec. The weapon has no altitude sensor.

The second option (9-A1-7759 with 9-Zh1-7759 combat tool) is equipped with the main high-explosive fragmentation and additional incendiary fragmentation warhead. The launch weight is 598 kg and includes the main 315-kg warhead and an additional 164-kg one (480 kg in total). Its combat power exceeds unguided high-explosive fragmentation OFAB-500U air bomb 1.5 times. Maximum range is 65 km and maximum flight time is 260 sec. Delay range is 0 to 170 msec. The weapon has no altitude sensor.

The third option (9A2-7759 with 9-Zh-2-7759 combat took) carries the modules of the main and additional fuel-air explosive warheads. The launch weight is 488 kg. The main warhead weighs 250 kg and the additional one - 129 kg (370 in total). Its combat power exceeds KAB-500OD smart air bomb two times. Maximum range is 65 km and maximum flight time is 260 sec. Detonation altitude ranges from 6 to 12 meters. The weapon is equipped with Grom-D altitude laser sensor.

All options are equipped with inertial jam-proof receiver of satellite navigation GLONASS and GPS systems. The launch speed for all three options ranges from 500 to 1200 km/h.

The report provides the results of ground tests. "Trials were held in a volume stipulated for the beginning of acceptance tests. In particular, acceptance and interdepartmental tests of components were held. Other trials included track, climatic, resource tests, as well as resistance to electromagnetic jamming, dust and sand, precipitation, aerodynamic heating, electromagnetic emission and shock wave of a nuclear explosion.

The ground trials exposed problems with the status of the third option 9-A2-7759, incomplete work to confirm the efficiency of events to increase protection from electromagnetic jamming and resistance to self-detonation during a 9-A2-7759 release from the carrier. Trials were delayed by unprepared equipment of the 12th Research Institute (the Defense Ministry said the institute has to substantiate development guidelines and maintain high combat readiness and efficiency of nuclear weapons of all types and arms of the Russian armed forces).

"30 flights of the carrier and five provision flights were held. There were three emergency releases, including two ‘non-explosive’ combat tools of the second and third options, and eight launches of telemetric products," the report said. The typical flight of 9-A-7759 released into the front hemisphere comprises the following stages: joint flight, terrain inspection by the carrier, mission assignment transmission to the control system and release, catapult launch section and stabilization of launching excitement, horizontal turn towards the target, diving at 30, 70 and 90-degree angles, and target destruction.Boost motor operates after release and pauses to switch on the main engine which operates until the dive.

The guided weapon can be released into the back hemisphere. The flight resembles the front hemisphere launch with a steeper horizontal turn to the target.

The publication provides launch results. 9-A2-7759 was initially released from an altitude of 10000 meters at a speed of Mach 1.2. Data were obtained to adjust the control contour. During the second launch of 9-A-7759 (altitude 10000 meters, speed Mach 1.4, distance to target 70 km) the missile was lost because of control adjustment error. The third launch of 9-A1-7759 (altitude 10000 meters, speed Mach 1.2, distance to target 20 km) hit the target with a 4-meter deviation. The fourth launch of 9-A-7759 (altitude 500 meters, speed Mach 0.8, distance to target 33 km) was carried out without satellite navigation. It was considered successful although the weapon deviated 76 meters from the target. During the fifth launch of 9-A-7759 (altitude 6000 meters, speed Mach 0.8, distance to target 33 km) one module broke down. The six launch fired 9-A-7759 from an altitude of 12000 meters at a speed of Mach 1.5 to a distance of 120 km. It was considered positive as the deviation from the target comprised 10 meters. 9-A2-7759 was tested during the seventh and eighth launches. The first of them (altitude 12000 meters, speed Mach 1.5, distance 66 km) deviated seven meters from the target and the weapon exploded seven meters above the ground. The other one (altitude 10000 meters, speed Mach 0.9, distance 66 km, azimuth 120 degrees) deviated two meters from the target and the weapon exploded 7.5 meters above the ground.

"The flight trials confirmed the tactical and technical characteristics of 9-A2-7759 which are 60 percent above the projected ones. The targeting error did not exceed 11 meters. During ‘non-explosive’ release the 9-A2-7759 self-detonated. Measures were taken to increase resistance to ‘non-explosive’ trials and their efficiency confirmed by autonomous tests," KTRV said.

The flight and launch trials were completed as scheduled in March 2018. The project was assigned letter "O" the same month. In April 2018 the weapons began acceptance trials. They are to be completed in September 2018. Ground tests have to rectify all remarks by August. The project is expected to get letter "O1" in November 2018.

By appearance the guided missiles resemble Grom-E1 and Grom-E2 which were displayed at MAKS-2015 airshow. KTRV CEO Boris Obnosov said they were undergoing trials at the time.

Both weapons have a normal aerodynamic scheme and a uniform cylinder ogival head with a foldable arrow wing. Thus, they can be carried both on outside suspension and released by AKU-58 catapult and inside a fifth-generation fighter jet. Grom-E1 is distinguished by an engine in the tail while Grom-E2 has an additional high-explosive fragmentation warhead instead. All basic parameters of the two new munitions were classified in 2015.

The designers only said the launch weight exceeded 600 kg. Grom-E1 payload was close to 300 kg and that of Grom-E2 exceeded 450 kg. They had a combined targeting system - inertial navigational system with GPS-adjusted trajectory. Both munitions have sufficient range to attack ground targets from outside facility-based air defense.

Obnosov said at MAKS-2015 the trials of Grom air munitions will be held on the MiG-35 multirole fighter jet. KTRV said the guided missile will be fired both from MiG-35 and Su-34 frontline bomber.

It is to be noted that KTRV is developing 12 guided missiles to be carried inside fifth-generation Su-57. The first six were to appear in 2017 and the rest by 2020. KTRV First Deputy CEO Vladimir Yarmolyuk said all the weapons for Prospective Airborne Complex of Frontline Aviation (PAK FA) will be accommodated inside the aircraft at the second development stage.

He said the weapons for PAK FA are developed in two stages. The first one adapts available missiles that have been tested on other aircraft. They are carried on suspension. The second stage focused on weapons to be carried inside the cargo compartment of the jet. They include antiradar missiles, short-range missiles with a major warhead, and medium and short-range missiles. They will be followed by long-range air-to-air missiles.

It was necessary to fold aerodynamic surfaces to accommodate the missile inside PAK FA. They have to unfold only after release and separation from the carrier. The width and height of the missile cannot exceed 0.4 meters.

Obnosov said orders for Su-57 missiles will not decrease despite cuts in the purchases of the aircraft with the first-phase engines. "It will in no way affect us as the universal missiles are necessary for PAK FA and other aircraft. A missile should be adapted for all types of aircraft, including Su-35," Obnosov said adding the missiles accommodated inside PAK FA can be carried on suspension by other aircraft.