RNAS Yeovilton is one of the Navy’s two principal air bases, and one of the busiest military airfields in the UK. It is home to more than 100 aircraft operated both front-line squadrons and training units including all Fleet Air Arm Lynx and Commando Helicopter Force, plus vintage aircraft of the RN Historic Flight.

The base is located near Yeovil in Somerset and covers around 1,400 acres with the main airfield in Yeovilton itself and the satellite at Ilton (Merryfield). Some 4,300 personnel, Service and civilian, including MoD employees and permanent contractors are employed on the site. The air station also hosts a large support staff from the Defence Equipment and Support organisation, and the world famous Fleet Air Arm Museum.

WildCat Trials on HMS DUNCAN

Powervamp was invited to trial its Coolspool 29 Twin aircraft start units on the Wildcat helicopters. The primary objective of the assessment was to prove the Coolspool Twin could spool up the turbines and, if so, also understand if a single unit could carry out a couple of starts as an alternative to the GPU 2400 aircraft start units currently in use at the base.

“…The clamp meter recorded a current draw of just under 800A…”

The Wildcat has a very sensitive electrical system meaning any external GPU cannot be switched off whilst connected to the aircraft due to the tripping of the helicopters circuit breakers. The NATO connector must be unplugged whilst the GPU is live to avoid powering down, re-setting the circuit breakers and powering up the avionics suite.


The Coolspool 29 Twin was wheeled into position to attempt a start. After the pre-flight checks were carried out the pilot initiated the start sequence and the engines spooled up without issue. The clamp meter recorded a current draw of just under 800A which was well within the Coolspools capabilities.  The Wildcat was successfully shut down after the twin pack had been disconnected.

“…The Powervamp aircraft start units are essential for providing portable power…”

A single Coolspool 29 aircraft start unit was re-connected and the pilot went through the start sequence again.  The unit spooled up the turbines without issue and proved convincingly that a Coolspool 29 could handle the high current draw of the Wildcat.


The pilot and engineers were satisfied that the trial had gone well and had proven that deployment with a single Coolspool 29 is possible.  It was also noted that the higher 28V DC from the Coolspool Twin offered an even better spool up than the 24V DC GPU 2400 Twin.

The Powervamp aircraft start units are essential for providing portable power whilst the Wildcats are away from base, deployed on board ship or on manoeuvres. All pre-flight checks would normally be carried out using the aircraft batteries, the aircraft start units would be used solely for turbine starts.

Powervamp would like to thank RNAS Yeovilton for their kind assistance during the trial, and look forward with working with again in the near future.


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