Staying conscious and alert while experiencing high G-forces is hard enough. Flying a plane at the same time is quite another, and for fast jet pilots, it’s a matter of life and death.
That’s why the Royal Air Force (RAF) has invested in a new high-G training facility, with a virtual cockpit that can go from 1G to 9G in one second – and can reach 12G for unmanned trials.
TechRadar visited the High-G Training and Test Facility at Cranwell in Lincolnshire to learn more about its state-of-the-art technology, and how it’s helping get the next generation of fast jet pilots ready for the air.
Handling high Gs
High-G training saves lives by helping pilots learn how to avoid G-force induced loss of consciousness (G-LOC). This happens when blood drains from the pilot’s head, causing them to black out, and is believed to be the cause of a tragic accident at the 2015 Shoreham Airshow, where a pilot crashed into a road while performing a loop manoeuvre.
Overseen by an RAF doctor, pilots at the facility can safely practice a technique called G-straining, which involves tensing the muscles in the legs and core to prevent blood pooling in the lower body, and performing controlled breathing to maintain consciousness.
David Bolsolver, former wing commander of the Red Arrows (the RAF’s aerobatics team), is the facility’s training manager. He explains that until now, the RAF has carried out G-force training using a centrifuge in Farnborough that first came into service in 1955. It worked well, but was a much simpler device and doesn’t meet the latest standards for training pilots to fly modern fast jets.
“In the old Farnborough simulation, you just sat there in a seat and you’d have nothing to do, because you’d just be sat there being tossed around,” Bolsover said.
“Here, the whole idea is you will fly the aeroplane type while you’re doing the G. You can teach anybody to G-strain if they’re just sat there doing nothing else. You then need the distraction of flying an aeroplane, because you’ve got to make that G-strain automatic, and that’s what this training’s for.”
The new simulator can also reach high G-forces much more quickly than its predecessor. The old device has an onset rate of 1G per second, meaning it takes nine seconds to get up to 9G. Current NATO regulations state that simulators should have an onset rate of 3G per second. The new centrifuge can reach 8G per second – the same onset rate pilots will experience in a Typhoon fighter jet.
The Cranwell facility cost £44 million (about $57 million, AU$81 million), and features a gondola attached to a seven-meter arm, driven by 20-tonne gearbox and drive capable of delivering over 4,000 horsepower.
The interior of the gondola can be fitted with three different cockpits – a Hawk T2, a Typhoon, and an F-35 Lightning – so pilots can get used to the specific control layout they’ll be using in the air.
“Everything’s generally flown by the pilot,” says Bolsover. “No pre-programmed runs – but we can do those for trials where we need consistency.
The simulation itself uses a database provided by the Ministry of Defence, and is based around RAF Valley – a Royal Air Force base in Wales. Pilots can ‘chase’ another plane, or fly through a series of virtual gates (think Pilotwings), and each flight produces a unique G-force profile.
Unlike the old Farnborough simulator, the Cranfield device has roll and pitch bearings on the gondola, so the pilot also experiences forces that aren’t just vertically down through their body.
Despite its complexity, the new facility was built surprisingly quickly – possibly in response to the 2015 Shoreham crash. It’s a partnership between aerospace company Thales, the RAF and the Ministry of Defence. Austrian company AMST provided the centrifuge itself, and construction company Galliford Try handled the building work.
Bolsolver explains that the facility began as an empty site in January 2017, and the building was ready by September/October time. AMST began installing the device in January 2018, and had it up and running in May. The facility was fully cleared to operate by the RAF in October, and officially opened in February 2019.
As well as Bolsover and the doctor, the facility’s team includes a general manager, two pilot instructors who facilitate the simulation, four engineers who monitor the centrifuge and perform day-to-day maintenance, and two safety equippers who are responsible for the pilots’ gear.
This equipment includes specially designed trousers that inflate to put pressure on the legs to keep blood from pooling, and add between one and two G of resistance. They also feature two large pockets for sick-bags – which the equippers say are often necessary.
Going for a spin
One of the pilots training during our visit (making 9G look surprisingly easy and definitely not reaching for those pockets) is Flight Lieutenant Nathan Shawyer, who currently flies Tornado, and is converting across to Typhoon. He says the biggest difference between the two is the G-force involved.
“That's the reason why I'm here – just to get that sort of awareness and get trained up ready for it,” he says. “This is a really good facility to be able to do that early, without having to actually do it for real and the aircraft yeah. Just working on that straining manoeuvre and the breathing techniques try and hold yourself awake.
“With Tornado we only pull about four or five G, so the G training for me up until now hasn't really been a massive part of my flying, but it will be with Typhoon, and hence the reason we brought it up to 9G today – to prove that we can do it and test the kit.”
Shawyer says the G protection, which inflates all the way from the feet to the chest, makes the forces a lot more manageable.
“The training here is very good in terms of getting the system right,” he says. “There are some differences, so in the training system here you're being rotated around, and it’s that centrifugal force that’s administering the G, so that means that when you're rolling in and rolling out of these manoeuvres you’re speeding up slowing down, you do get a rolling, tumbling sensation now that in the aircraft you don't get because it's just a snap to the G and then roll straight out again. There are some subtle differences, but short of actually sending you up in the jet, this is the next best thing."
He's been for some passenger flights in the back of a Typhoon to experience it, and expects to go up himself in a month’s time.
“There’s about a month of ground school, and some simulators packed in there to learn all the systems with Typhoon,” he says. “Clearly it's a massively different cockpit and training setup from the Tornado, which I'm used to, so that'll take some time to get used to, and after about a month or so I should be up in the air.”
Cranwell is the only facility of its kind with an F-35 cockpit, and it’s hoped that other NATO nations will soon begin using it as well, keeping pilots safer around the world.
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