Pure Jet Engine Afterburner Sound "Without Music".

The high pitch whine and hiss you here is caused by the Avpin starter, which is on the front of each engine, this produces a rush of gases, into a primary turbine which winds the engine up to 34% within 9 seconds. By that time fuel is being pumped to the engine and its dragging its own air, a very simple way of starting jet engines in the days before electric starters.The two wheeled trolley under the starboard wing is known as a trolley Ack,it uses 2 12v lorry batteries, this gives us 24V which is the minimum voltage required to run all the pumps, etc prior and during the start of each engine. (28v is the 'peak' voltage)