UK Edition
My head felt like a bowling ball balanced uneasily on my shoulders and it was hard to lift my arm into the air. I had to fight to regulate my breathing as I’d been taught in the pre-flight brief and the specially-designed clothing inflating around my legs and stomach was forcing me to tense every muscle to stop blood draining from my head.
I was strapped inside the RAF’s new High-G centrifuge, officially unveiled today at RAF Cranwell in Lincolnshire by the Chief of the Air Staff, Air Chief Marshal Sir Stephen Hillier. It is designed to allow fast jet pilots to experience increased G force and mitigate its worst effects.
When G force is increased, blood in the head is pulled down to the lower part of a human’s body. Vision can quickly shut down - known as ‘greying out’ - and, if not corrected rapidly, loss of consciousness is likely to follow.
As I spun round in the centrifuge I preempted the onset of G force with the muscle-straining techniques I’d been shown, to keep my blood pressure up. Squeeze a beach ball between your legs, push your feet down and tense the calfs, thighs, abdomen and buttocks, I’d been told.
At 3G I started the breathing techniques: I held my breath against a closed throat to put pressure on my heart and raise my blood pressure even further. I’d hold that for three seconds then quickly exhale and inhale again, to keep the pressure up.
The centrifuge spun faster. At 4.5G - the limit for a civilian - the suit was punching me in the stomach and just staying alert was an effort, as my body, in effect, weighed over four times its natural weight.
The new £44million, 39-tonne centrifuge has a single 7.5 metre arm. It will be used by fast jet pilots in the Royal Navy and Royal Air Force to replicate flight in aircraft such as the Hawk, Typhoon and new F-35 Lightning aircraft.
Pilots are able to experience up to 9G - nine times the normal gravitational pull of the Earth - and learn how to use their specialist in-cockpit flying equipment to help them cope with these stresses.
In comparison, a fairground roller coaster reaches about 2G and an ejector seat operates at about 30G.
The centrifuge can accelerate up to 9G - 60 mph - in one second and rotate up to 34 times a minute. The RAF says it will revolutionise training as pilots are not simply strapped into the device and exposed to G-force but are able to fly as they would in a flight simulator.
The Chief of the Air Staff said it was a step-change in pilot training.
“By exposing our Typhoon, Lightning and Hawk pilots to High-G forces in a tailor-made and completely controlled environment, we are significantly enhancing safety in the air and making a major contribution to our operational effectiveness,” Sir Stephen Hillier said.
Quite often after a High-G run pilots can experience petechial haemorrhage, known as ‘G Measles’, when capillaries burst, leaving the pilot with red spots on their body.
Group Captain Chris Moon, Station Commander of RAF Valley in Wales, said High G sessions were “brutal”.
“If you don’t strain against the G and you haven’t got the G trousers on, at about 4G the pilot will start to grey out,” he told the Telegraph.
“In the past aircraft have been lost through G-LOC - G-induced loss of consciousness - when the blood drains from the eyes and brain. G-LOC is the known cause of several accidents over the last few years.”
As a pilot approaches G-LOC they would experience tunnel vision through blood loss to the eyes, then pass out. As they relax on the controls the G force should come off as most aircraft would return to stable flight, but crashes do occur. After two or three seconds the blood would reach the brain again and the pilot would come round, experiencing disorientation for five or six seconds. “It’s not much fun,” says Dave Bolsover, the centrifuge manager, former Red Arrows pilot in the RAF and veteran of the Gulf War.
The facility has been built by Thales UK, the global defence and technology company that has been training RAF aircrew since the 1930s. Over that period the contractor has provided over 300 complex simulators for 60 different platforms.
The existing High-G facility was built in the 1950s and no longer matches the performance of the modern fast jet aircraft such as the F-35 and Typhoon.
I flew at 4.5G for about two seconds and was glad for a cup of tea afterwards (with added sugar on the RAF doctor’s orders). To pass their five-yearly tests F-35 and Hawk pilots have to fly at 7.5G and Typhoon pilots at 9G for 15 seconds. Respect.