Unlike some G-suits worn by military pilots around the world, the Red Bull Air Race World Championship G-Race Suits don't require a connection to the plane – they are completely autonomous and use 'fluid muscles' in place of pressurised air.
When a pilot sustains G loads, instead of using air pressurised compression systems, the 'fluid muscles' sewn into the G-Race Suit helps to maintain the pilot's circulation. Water-filled tubes run from the pilot's shoulder, down his abdomen and legs and to his ankles. At high G, the water quickly flows downwards, and compresses the thighs. This means that the pilot's blood won't pool, and can keep pumping into his upper body/head where it's needed.
Wearing a G-Race Suit helps the pilots cope with an extra 1.5G, with less effort required to sustain the extra G-Force. This prevents the pilots from becoming becoming exhausted flying in the racetrack.
Each G-Race Suit is tailored for every pilot in the Red Bull Air Race World Championship – 48 different measurements are taken from around the body such as the ankles, calves and knees.
The suits weigh around 6.7kg and each contains around 4 litres of fluid. The fluid muscles have to be replaced annually as the fluid can evaporate over the course of a year – around 20-30ml. If more than 50ml is lost then the fluid muscles are replaced.
Because the G-Race Suit has to fit like a second skin, it includes a special lacing system. It is around 90% tailored to fit, and 10% lacing to allow for changes in muscle tone and weight gain or loss throughout the season.
The suits use a 'passive' system, which means that pilots can't feel the movement of water through the fluid tubes and can only sense a small amount of pressure from the extra G-Protection that the suit offers.
Specialised spacers inside the fluid tubes prevent the flow of water from becoming restricted, even if the pilot puts extra pressure on the fluid tubes from the harness or bending.
Each G-Race Suit is tailored with Nomex – a flame retardant material – and Twaron, a material with the strength of Kevlar but flexible enough to allow for changes in its shape and tension as water flows through the expanded fluid tubes.
In hot locations like Putrajaya, the G-Race Suits are often chilled in a fridge before each flight – this gives the pilots around 20 minutes of a 'cooling effect', helping them to better manage the stresses of heat and humidity.