Hawker Restoration and its sister company Hawker Racing are passionate about what they do, this passion has led to the former being the world’s foremost restorer of the iconic Hawker Hurricane aircraft, having restored or worked on 13 of the 15 remaining airworthy planes and the latter being highly successful in restoring and replicating pre-1966 grand prix and sports cars, gaining honours in many historic races for its customers.
As you can imagine this type of work requires many parts to be manufactured from either original blueprints or from fresh designs, as owner Tony Ditheridge says” There are literally 1000s of components that we have to manufacture, from suspension, gearbox and steering on the cars to undercarriage, wing fittings and hydraulic components for the aircraft.” In addition to the relatively modern Hurricanes, Hawker Restorations also works on older aircraft and proof of this is seen on a desk in Tony Ditheridge’s office, where a nine cylinder rotary engine sits waiting to be restored and fitted to a replica 1916 Sopwith Camel that is being built for a customer overseas.
Often in the shadow of its contemporary, the Spitfire, the Hurricane’s record shows that it was by far the most successful of the two, shooting down 656 enemy aircraft compared to the 529 of the Spitfire. The Hurricane was also a more complex aircraft than the spitfire’s monocoque frame, which may account for the fact that only 14,583 Hurricanes were built, compared to 22,000 Spitfires and only 15 remain airworthy compared to 45 Spitfires. The complexity of the construction meant that Hawker Restorations almost didn’t ‘get off the ground’ as it couldn’t justify the cost of tooling and materials, then in 1993 it was approached by New Zealand-based businessman and aviation enthusiast, Sir Tim Wallis, who funded the materials to restore the first three Hurricanes. One of these was shipped to Sir Tim in New Zealand, the second went to Microsoft co-founder Paul Allen, and the third by Steven Grey of The Fighter Collection at Duxford.
All of this requires a machining capability and while many of the 15 employees are highly skilled toolmakers who could make use of the manual machines on-site, Hawker Restorations put the majority of its machining out to sub-contract, with fellow aircraft enthusiast and Rolls Royce Merlin engine specialist Maurice Hammond at Eye Tech Engineering, but with business increasing it was decided to enhance the service provided by Eye Tech and its XYZ Machine Tools, with a new in-house machining facility. “We have more than enough work to keep Eye Tech busy, but we recognised that we also needed our own CNC machining capability, especially and primarily for our historic racing car business, so we took the decision to invest in some XYZ Machines of our own. That continuation means that in effect, every machined part that we use on our aircraft has been on an XYZ machine at some point, whether ours or Eye Tech’s,” says Tony Ditheridge.
The machines bought by Hawker Restorations are an XYZ SMX 3500 bed mill and an XYZ ProTURN SLX 355 lathe. Both machines are controlled by the ProtoTRAK control system, which was a logical first step for the team who had no experience on CNC control prior to the machines being delivered. This lack of CNC knowledge did, as Tony Ditheridge admits, caused some resistance to change initially, as the norm was to get on a manual machine and ‘handball’ every job. The simplicity of the ProtoTRAK control soon won over the doubters, though, and it quickly proved its worth. “An example of the difference was when we had to cut a large diameter hole in an aluminium plate. Previously this would have been chain drilled on our manual machine, with ProtoTRAK it was a simple job of programming the machine to interpolate the hole. In fact every job is so much easier with the ProtoTRAK control.”
The XYZ SMX 3500 bed mill sits in the middle of the XYZ bed mill range and features a 3.75 kW (5hp)/ 5000 revs/min, 40 ISO spindle, with two speed ranges. A wide range of components can be accommodated by its axis travels of 787 by 508 by 500 mm (xyz), with additional quill travel of 128 mm, the machine’s table size is 1372 by 356 mm, with a maximum load capacity of 600 kg. Further versatility is provided by the head, which can be tilted 45 degrees either side of the vertical. The XYZ ProTURN SLX 355 has a 360 mm swing over the bed (225 mm over the cross slide) and between centre distance of 1000 mm. With a 5.75 kW (7.5 hp) 4000 revs/min spindle it is a very capable machine backed up by solid cast bed that provides a highly stable machining platform. As with the SMX mills, the SLX lathes can be operated under full control of ProtoTRAK, in full manual operation, or in the TRAKing mode, which allows the operator to wind the handwheel to move the machine through the program. This facility is ideal for those who want to check a program before committing to full CNC mode, giving the operator greater confidence and, once happy with the program, the operator simply presses the cycle start button and the program runs fully automatically.
To ensure that the potential of the ProtoTRAK control is maximised three toolmakers from Hawker Restorations underwent training, initially spending one day at XYZ’s Waltham Abbey showroom to learn the basics, which was followed up by a further, more advanced day of training once they had familiarised themselves with the system. For ongoing support, and as they start to look at more complex components they will have full and free access to XYZ’s programming hotline, which provides support to all customers who feel they need any extra advice on either the ProtoTRAK or Siemens controls systems supplied by XYZ Machine Tools.
This extended support may well come in to play with one project that is in the planning stages at the moment. Sitting in the workshop of Hawker Racing is a unique Parnell Supercharged 1934/36 MG K3 racing car. This car has the original twin cam engine fitted, which is the only engine of its kind in the world. Hawker Racing now has the patterns and drawings for the engine and the plan is to manufacture brand new engines of this type, with all of the machining, again, being undertaken on the XYZ machines.
(Above) A selection of the historic grand prix cars restored by Hawker Racing.
(Above) Hawker Racing makes full use of the XYZ machines to produce steering, braking and suspension components.
(Above) The new machining facility at Hawker Restorations.
(Above) The MG K3 is fitted with a unique twin cam engine, Hawker racing will use the XYZ machines to produce new engines from the original drawings and patterns.
(Above) Undercarriage components machined on the XYZ Machines at Hawker Restorations.