The Plessey Dynamics Group builds the Plessey engines that are used in aviation to start turbines.

-They are used on the Royal Navy and RAF Phantoms. It is the "Solent" of 70 HP.

“Plessey”

-The one in the figure above is used for military RR Spey turbojets and among its advantages is that it uses the aircraft's main fuel.

-It has a reduced consumption, 1 gallon every ten starts, being an autonomous system as well.

-These starter engines have an unlimited number of start-ups (unlike the Coffman type cartridges that need to be recharged).

-General reviews (Overhaul) are due every 1,000 Hrs. Maintenance services had to be skilled not only on airplanes and their main engines, but also on accessories like these.

-It can be used for all kind of starts, also for auxiliary engines like the "Meon", another turboshaft used as an APU.

From Appendix 6: Autonomous Starter Motor. It runs on the same fuel as the aircraft's main engines.

-It is a small turbine rotating at high speed that can bring the main engine to idle speed in 10 seconds.

-There were several models and powers. Like the one in the photo of a Plessey Solent Mk2, manufactured by Plessey Dynamics for British F4 Phantoms, placed on a provisional bench.

“Plessey starter”

“Solent Mk2”

-We found an image from around 1936 when the then called "Plessey Company plc" made engine accessories, including this cartridge-type starter with various selectable revolver loads.

"Starter with multiple cartridges"

-We see the loads on the left, the turbines and gearbox next to that. The loads are on a rotating drum.

From Appendix 9: A manufacturer of accessories, including the small Solent Mk101 starter turbine.

“Plessey Solent and operation scheme”