November/December 2014

I bought this engine about a 18 months ago from Everett’s down in Ipswich. Jamie Everett had a few of them so Ian, Adrian and I  had one each. The engine comes from the old Nimrod and although called an APU does not actually supply any form of power apart from compressed air to start the engines.

This little engine is surprisingly simple and should only need some basic electronics to get it up and running. We’re going to need a control box, a soft start for the starter motor, an igniter box and a load of relays.

 

Most of the pipe work is on the front as shown above. I will use Adrian Bennett’s mod to allow a VR sensor to be fitted to the oil pump so that we can measure the RPM of the gas generator.The picture above shows the compressor which resembles that of a huge turbocharger. In order to run the engine a bleed or anti-surge valve is required to provide a load and prevent it from over-speeding.

I’ve started to build up a control box and also an engine control unit. The RPM gauges will be homemade bar-graph type using LED’s.

The ECU contains the electronics for the starter control in addition to the RPM signal conditioners. The old LM2907 comes to the rescue again!