The K9 “Thunder” chassis for the 155 mm self-propelled howitzer, developed by the Polish and Korean designers, is the carrier mentioned above. The new chassis - in line with the specification developed by the STALOWA WOLA S.A. steel-works, who acts as an industrial partner and party of the agreement signed by the Hanwha Techwin company - features a variety of structural changes. This phase of works, related to the “Regina” programme, and the struggle to save the initiative, was described by us directly after the turret was integrated on the newly developed carrier.
The final test programme, scheduled before the vehicle is going to be handed-off, has been concluded with a series of live-fire tests. During the programme, the howitzer fired five shots, including shots with the use of maximum (sixth) powder charge. The test-firing was conducted with the use of ZM DEZAMET and Rheinmetall ammunition. The test firing with the maximum quantity of charge is very significant, when it comes to verification of the strength assumptions related to the turret – chassis interface. Due to the limited area of the firing range, making it impossible to carry out test firing at the longest range, some tests were executed by firing the howitzer directly aimed at a bullet trap. The remaining tests were executed at angles, but with the use of weaker charges, in order to make it possible to place the shots within the test range area.
New chassis was tested with all of the possible turret positions, with regards to the longitudinal axis of the chassis, also in positions 90 degrees left and 90 degrees right from the axis, and also with the turret pointing backwards. At each of the positions, results “above satisfactory” have been achieved. The howitzer seemed to be very stable, throughout the whole testing procedure. The laboratory analysis of the testing results, including the load distribution data and amplitudes, fully confirms the assumed stability of the hydro-pneumatic suspension of the carrier, which plays an important role in dampening the vibrations of the whole system, after the shot. This has an important impact on the rate of fire, as it is not limited by the chassis. The howitzer is capable to fire three shots throughout 10 seconds.
Directly after the test programme has been completed, a representative of the Armament Inspectorate passed an approved certification test programme document to the President of the HSW company. The said programme is going to be carried out in case of the example that has passed the tests described above. According to the Agreement with the STALOWA WOLA works, the company is obliged to complete the tests until April 2016. The management board of the HSW company declares that the test programme is going to be significantly shortened, however, this is going to be largely dependent on the weather conditions in the upcoming weeks.
Second example of the Krab howitzer, on the new carrier, has been assembled at the HSW SA company already, however, it is not going to be used in the test programme which is already being officially realized. Soon, acceptance tests, regarding the second example of the howitzer, are going to be executed.