Taming the leopard

When the new Leopard II tanks are in the field, it doesn’t matter that they have an exhaust noise level well above 100 dB(A).  But when civilian mechanics are maintaining them, then the National Working Environment Authority’s rules apply, meaning max. 80 dB(A).

When repairing and maintaining the engines from the giant Leopard II tanks, out of the vehicle, the engines need to be test run before reinstallation. Initially the engines were run in an unsilenced condition, outside the garage facilities, which was unsatisfactory and did not meet with the National Working Environment Authority approval. To resolve the situation HM Akustik A/S built special purpose test cabins, incor-porating a low noise control room. The first cabin supplied to the Danish Army experienced problems meeting the guarantied exhaust noise levels and Silentor was involved. Using new patented technology, Silentor was able to fulfil the requirements with a significant margin of attenuation.   A further five test cabins have been delivered to the Danish Army, all performing with unprecedented results. Silentor designed a complete exhaust system, including a “Y” piece from the twin turbo chargers, the silencer, complete with supports, and tailpipe assembly with a weather cowl. The silencer, in this case a class 45 dB and the exhaust system, gave only 250 mm Wg restriction.   The test cabin and the silencer combination are so effective that the noise levels 1 meter from the cabin is below 85 dB(A) and the control room noise is down to 75 dB(A). Excellent results when considering the noise level in the engine test cell is near to 120 dB(A) and the unsilenced noise from the exhaust is even louder. All parties concerned are delighted with the outcome, none more so than the National Environment Authority.   Print case story