What exactly is a G-inspection?

Technical Director Jim Reed explains all…

Stripping down the raceplane

In the Red Bull Air Race the pilots enter the track at 200kts and by the time they reach the first Vertical Turning Manoeuvre (VTM) they could be going even faster! That's when they pull hard back on the stick and try to turn their raceplane around as quickly as possible, without breaking the rules of the sport and exceeding the 12G limit.

Every millisecond is vital and can be the difference between winning and losing, so the pilots will try and push as hard as possible. When testing the boundaries of a racetrack pilots can incur a two second penalty for an over-G (if they pull over 10g for more than 0.6 seconds) or a DNF if they exceed 12G – the margins are incredibly tight!

So when a pilot exceeds the 12G limit they're given the order by the race tower to 'RTB' Return To Base, as their raceplane will need to undergo a G-inspection.

Red Bull Air Race's Technical Director Jim "Jimbo" Reed, used to be the technician for Nicolas Ivanoff and knows what is involved in a G-inspection, but now he's on the other side he has to ensure that the technicians are doing the job correctly.

"The G-inspection is the responsibility of the team technician," said Reed. "They will strip the aeroplane apart, carry out all the checks, sign each section of the check sheet to say everything is good and then I'll, or a delegate, will go and look at the raceplane and decide if it's good. So it's their inspection and then the final check is done by me or a delegate. If they do find anything we of course will look over it together."

Reed mentions 'delegates' – qualified members of Reed's team – because at the recent race in Abu Dhabi, the track was so fast that a lot of pilots were pulling more than 12Gs and therefore a lot of raceplanes needed inspecting in a short amount of time.

Although the technicians have got the G-inspection down to a fine art, it is still a process they would rather they didn't have to go through. It begins with stripping back the raceplane as far as the manufacturer has recommended.

There are different checks for each variation of raceplane, the Edge 540 V2 differs slightly from the V3 and the MXS-R is a different process altogether, thanks to its monocoque structure.

"For the Edge, the checks include [but aren't limited to], the cowling, the forward fuselage panel just ahead of the cockpit, the small tail cover, the last foot of two of the turtle deck for the V3s and the entire turtle deck for the V2s, as it comes off as one piece," explained Reed. "Once that's all off you can see the engine mount, the wing attach points for the main spar and the aft spar, the seat and seatbelt attachments, all of the truss tubing and the vertical and horizontal tail attachment," he added.

The technician is looking to see if anything has moved or become compromised. "We also look at the surfaces of all the composite parts, trying to see if the skin is buckled or deformed. You look at it with a torch to see if there are any deformities. We look at it a million times so we can spot anything irregular."

Reed went on to explain it's a lot like looking down the side of a used car you're about to buy, you want to see if there are any dents or deformities that might belie its clean history.

The MXS-R also needs to be checked but it is a different format to the Edge due to it's monocoque structure. "It doesn't have the steel-tubular fuselage, so we check the engine mount, the engine mount gears, the engine mount attachment to the raceplane, the surfaces of the fuselage and the wing and tail. There are also two panels under the wing at the root, where you can pop those off, and the spars and tension caps and all the fittings and how they're fitted to the fuselage," said Reed.

As with everything in the Air Race the pilots want to be flying so the technicians know exactly what to check and have got their G-inspections down to a fine art. "The techs can do it pretty quickly," said Reed. "In terms of time the MXS-R is the fastest because it has the least to take apart, and that'll be about 30 minutes. The V2s are a bit more complex than the V3s, in terms of the way the panels don't come off individually so it takes a bit longer but it's about 45 minutes in total," he added.

So far all these inspections have found very little and are testament to how robust the raceplanes in the Red Bull Air Race are. "We haven't found much in the past, knock on wood, they're super strong," concluded Reed.