IDEF 2025 – Assan group unveils Firtina hybrid powerpack proposal and new bunker-buster bomb
At the IDEF exhibition in Istanbul the Assan Group, which this year celebrates its 40th anniversary and operates in multiple sectors, including defence, unveiled two new products, the new hybrid powerpack proposal for the upgrade of the T-155 Firtina self-propelled howitzer, and a national answer to enemy bunker destruction from the air
On the Assan stand a wide area was dedicated to power solutions, one remaining under veil for some time until the official disclosure. This was the hybrid powerpack that the company is proposing to the Turkish MoD for the upgrade of the 155/52 mm Firtina self-propelled howitzer, of which over 280 are in service with the Turkish Land Forces.
The powerpack is of the serial-hybrid type and is based on two 450 kW electric motors to which a 460 kW 6 cylinder in-line diesel engine is added. Developed in-house on company funds, the powerpack can work in four different modes, the most powerful being the one combining both diesel and electric systems which brings to a combined power of 1,360 kW; which means an equivalent of 1,824 Hp compared to the current 1,000 Hp provided by the MTU 881 diesel engine installed on in-service howitzers. With a combat mass of 47,000 kg, the current power-to-mass ratio is slightly over 21 hp/t, while with the new hybrid powerpack, when used combining electric and diesel propulsion, this will increase at over 37 hp/t, considering that mass will increase to around 49,000 kg. Part of the 2,000 kg increase is due to the powerpack itself, which mass is short of 5,000 kg. The powerpack includes a new transmission, with 2 forward and 2 reverse gears.
Maximum speed is marginally increased, from 65 to 67 km/h, but what is considerably improved is acceleration, the estimates providing the SP howitzer to reach 32 km/h in less than 7 seconds, mostly due to the high torque of the electric motors. Assan estimates maintain the typical mobility performances, such as a climbing ability on a 60% gradient and that on a 30% side slope.
A key element is the 130 kWh battery pack, which is based on semi-solid state batteries, which can be recharged in less than half an hour. Regenerative braking allows recovering part of the energy, the diesel engine also working as a generator to recharge batteries when needed. Assan declares a range of 600 km for the howitzer.
At IDEF 2025 company officials told EDR On-Line that the powerpack development is finished, static tests having been conducted successfully. The company plans to install the system into a T-155 in September for field trials, and looks forward to a contract with SSB in due time.
Another new system present at the Assan stand was the SZ-109 bomb, developed by the company and produced in small quantities for qualification purposes, such tests being planned from September 2025 on, around one year being required to reach full qualification, the new bomb being therefore available in late 2026.
The bomb name indicates a link to the US BLU-109 bunker buster ordnance, Assan saying that its performances were improved also thanks to the use of advanced simulation software, the SZ initials remembering the late Şakir Zümre, the man who produced the first bomb in Turkey. EDR On-Line understood that the first four bombs were produced using the barrel of a 203 mm (8-inch) artillery barrel, which thickness and high pressure resistance is compatible with the ordnance characteristics. The SK-109 is 2,410 mm long, has a 370 mm diameter, and a mass of 885 kg (short of 2,000-pounds). The 255 kg warhead, which features a kinetic energy penetrator produced in special alloy, was initially loaded with Tritonal, a mixture of 80% TNT and 20% aluminium powder, however the final product will be loaded with PBX composition. First tests were carried out successfully at the TübitakSAGE Kaparinar firing test and evaluation centre, the warhead being mounted on a sledge. Assan declares a reinforced concrete penetration capacity of 2.5 metres. The SZ-109 can be fitted with guidance systems ranging from INS/GNSS to Semi-Active Laser.
Photos by P. Valpolini
