On the attack

Competing in the UK Pro Time Attack series, Gobstopper 11's specification makes exciting reading for any motorsport enthusiast and includes nitrous oxide injection, six speed sequential paddle shift Modena dog gearbox, WRC spec Exe-TC suspension, carbon propshaft, and GKN rally driveshafts.

The car started life as a standard Subaru Impreza with 280bhp and 8,500 maximum rpm, but through the use of a number of highly complex components, manufactured with Edgecam, it now develops 840bhp and can safely go to 10,500rpm.
Run by Roger Clark's sons Olly and Matthew, Roger Clark Motorsport focuses entirely on the Subaru Impreza marque, using Gobstopper 11 as the test bed to develop components and solutions to provide even greater levels of power, which are then sold commercially to Subaru Impreza owners.

“In Time Attack trials we compete against the clock, not against other cars, and there are no rules or restrictions regarding the car. In order to push the boundaries as far we do, the components have to be the very best they possibly can,” Olly – who drives Gobstopper 11 – explains. “There's no compromise on the car build, nor the way it's driven. I need to have every confidence that the parts used can withstand the incredible strains and stresses they're under, especially as we're putting 850bhp through the engine.”

Based in Leicestershire, RCM was established 21 years ago and has a longstanding relationship with motorsport and aerospace subcontractor, MP Engineering. “They provide an incredibly rapid response to our engineering challenges coming up with viable solutions that make Gobstopper 11 so successful,” Olly adds. “As well as prototyping and manufacturing new parts for us, MP Engineering also modify existing components such as the block assembly and cylinder heads which make the car more powerful. They are involved with over 300 processes operating in the car during a Time Attack trial.”

Jason Poole is production director at MP Engineering. “We certainly couldn't create such highly complex 5-axis components for the car without Edgecam,” he reveals. “We did try other software packages but they all fell short in terms of performance. Edgecam means we can bring new parts to the track extremely quickly. The car contains several hundred of our components for any Time Attack trial, including at least 20 parts for the sequential gearbox alone, along with engine components, mountings, differential covers, clevises for the suspension, dry sump pans, pulley sets and battery clamps.”

Edgecam, from Vero Software, drives MP Engineering's nine 5-axis Matsuura, DMG Mori and Bridgeport CNC machines, and four 3-axis Bridgeports. Senior project engineer Phil York says it takes around eight hours to put the toolpaths down on components such as the differential cover. “If we didn't have Edgecam it would be several weeks' work,” he says. “For most RCM parts, the designs are created in conjunction with Matt Clark and the solid model imported seamlessly into Edgecam. This allows us to accurately visualise the part, apply material, analyse it, decide what cutting tools we're going to use and which machine tool we'll program it for. Then we work our way through the relevant cutting strategies.”
He says with around 40% of the RCM components – and 70% of its total motorsport and aerospace parts – being milled in five axes, Edgecam's powerful simulation facility is also an essential tool. “We can't afford any collisions with the fixtures or machine tool.”

MP Engineering was founded by Jason Poole's father in 1981, manufacturing fixtures and jigs. It has now developed into a highly skilled specialist subcontractor, operating with 30 employees, manufacturing high precision components for the aerospace and motorsport sectors, including a number of Formula 1 companies, such as Red Bull since the RB3 car was developed.

“Edgecam's ability to program 5-axis components is unparalleled and its importance to us cannot be emphasised enough,” Mr Poole explains. “Without it, our significant investment in 5-axis machining centres would be wasted – other software simply cannot give us what we need in terms of manufacturing the highly complex components now required by motorsport and aerospace customers.”

Olly Clark concludes: “MP Engineering not only provide us with a fast turnaround on one-off parts for Gobstopper 11 – once those components have been successfully tested on the car, they also manufacture them for us to sell commercially to Impreza owners looking to improve the performance of their roads cars.”

MP Engineering
www.mpengineering.co.uk

Roger Clark Motorsport
www.rogerclarkmotorsport.co.uk

Edgecam
www.edgecam.com