The Manic Beattie Hillclimb Car
The MANIC BEATTIE,an extremely innovative 4 wheel drive CLUBMANS type chassis designed by NIC MANN of the famous ROVER V8 TURBO MOGGY fame. We designed a special 1700 BDT unit with special cylinder head, bronze gas sealing rings and other trick bits, to produce at the moment around 400bhp. This unit is blown with an HELICOPTER TURBINE, which is mounted in the car and uses it’s own fuel system to produce boost which remains at a constant pressure at all times, is then fed into the BDT, permanent boost! NO LAG. This unit was mapped on our dyno using a RACE TECH DEVELOPMENTS ecu with a 6 layer mapping facility with fantastic results.
We had to knock a 12 inch diameter hole in the wall to get the exhaust out of the cell. As the exhausts on turbines are critical, restriction is bad news and so we ran the engine with no exhaust, it sounded like a 747 was flying over the workshop for two days!
NIC broke the 20 year old unlimited sports car record at SHELSLEY WALSH with a 26.43 second run.
THE sport of speed hillclimbing is one of man and machine against the clock. That never-ending desire to save the odd hundredth of a second can often become a life long obsession. To the driver, it is all about optimum starts,perfect lines and higher corner exit speeds. To the engineer, it means more power, better traction, improved chassis balance and long hours in the workshop in pursuit of the dream. Nic Mann’s quest for that one, perfect run dates back to the mid-1970s. Having just graduated from Aston University with an engineering degree and found work at Rolls Royce aero engines in Bristol, he took up sprinting. The car he used was his mother’s Morris Minor 1000, complete with 948 cc ‘A’ Series engine. Over a period of 15 years this was progressively modified. At one point it featured a turbocharged B series unit and, eventually, a turbocharged and intercooled Rover V8 with nitrous injection giving something in the region of 550 bhp.
To cope with the increased power the vehicle initially had a Ford live rear axle and, finally, a Jaguar XJ6 rear driveline. “Throughout this period it was fully road legal and was driven to and from meetings with the racing wheels and tyres strapped to the roof!” recalls Mann. In 1990, having reached a plateau in the car’s engineering development, together with the arrival of a new family, the car was sold to drag racer Bill Sherratt. It still competes in that category today.
So what does a seasoned hillclimber do when he has a budget of £10,000 just sitting there in his pocket? Obvious – he embarks on a new project!
“Since the Morris had over the years been something of a crowd pleaser, its replacement couldn’t be something ordinary,” says Mann. “Yet even in 1990 £10K wouldn’t get you very much of a competition car. “Analysis of the competition showed that successful cars were compact. With the opportunity for aerodynamic downforce limited because of the low average speeds, mechanical grip had to be maximised. Soft suspension (to cope with the uneven surfaces), large wings and the ability to maximise downforce from the underbody were also required. With two-wheel drive, the weight distribution would be heavily biased towards the rear, resulting in large weight variations on the front wheels during transient power changes and issues with handling and stability.” The successful cars had F1-derived power units but their power delivery was thought to be ‘peaky’, making car control even trickier in the confined width of a typical venue. The critical key features of any new design would therefore need to be:
- Maximise mechanical grip, which effectively meant four-wheel drive and low unsprung weight (with inboard brakes).
- Minimum weight and polar moment of inertia within the constraints of cost.
- Major components grouped around the centre of the vehicle and small diameter tyres. The latter also minimises the size and weight of the final drive transmission hardware.
- Minimise the effects of lateral weight transfer, while retaining a compact package.
- A low centre of gravity was considered essential while front/rear static weight distribution was targeted at 50:50.
- At 1G acceleration, the targeted centre of gravity should give a 1/3:2/3, front-rear weight distribution.
- Chassis construction technique had to be suitable for low cost home build consisting of a steel spaceframe chassis with separate bodywork.
Eventually he concluded: “Careful consideration of all these factors pointed towards a layout with the engine in front of the driver and a ‘sports car’, Mallock type body with a four-wheel drive system based on a proprietary 4×4 transmission. Use of a flat floor allowed the hardware to be mounted as low as possible, with downforce generated primarily from the large wings allowed in the sport rather than from the underbody surface.” At this stage of the design process one could be forgiven for thinking that this was just a routine design and build exercise. However, it is in the power train where much of the real technical novelty resides. With the additional drag of the transfer gearbox and the forward drive system, not to mention the additional weight, Mann reckoned on needing at least 600 bhp on tap to generate the record-breaking performance he was looking for. Expensive F1-style ‘V’ engines were out of the question, not just on cost but because packaging in front of the driver would have been impossible.
Eventually help in the form of respected engine tuner John Beattie came to hand with the arrival of a 1700 cc Cosworth BDT. Canted over at only 25 degrees to the horizontal towards the intake side, this satisfied the requirement of minimum centre of gravity and minimised the frontal area and yet still left room for the driveline forward. “With 400 bhp the initial aim, it was evident that a move to a larger turbocharger and quite a large amount of boost would be necessary,” says Mann. “This would result in the dreaded turbocharger lag and while anti-lag or ‘bang-bang’ systems were considered, it was quickly decided to move to a much more radical solution.” Mann’s background in aerospace led him to a solution involving a helicopter gas turbine APU or auxiliary power unit. Supplied by Turbine Technologies Ltd of Carmarthenshire in South Wales, the unit is based on a helicopter emergency air start unit used to fire the main gas turbine engine on the ground.
Running separately from the main engine, initially on diesel fuel, the unit delivers air to the engine at a constant pressure independent of the main engine speed and hence totally eliminates the throttle lag normally associated with high boost turbocharged systems. Currently set at a very “modest” 25 psi gauge boost, the engine delivers something in the region of the initial target of 400 bhp at 7500 rpm. The torque curve is particularly impressive: from 2500-7500 rpm this doesn’t vary by more than 20% from the peak value. It was transmitted to the gearbox by a somewhat elderly AP Racing 7.25-inch triple plate, sintered clutch hidden within the radically modified Ford bellhousing. From the outset the car was designed around a Ford Sierra 4×4 MT75 gearbox, which at the second-hand going rate of about £300 each fitted nicely with the budget. However, as Mann was to find out later, this has been a major stumbling block to development.
With no finance to fund a dog gear conversion, he has resorted to removing the synchromesh cones to speed up changing gear. “Ratios were standard Sierra 4×4 with second gear giving 60 mph, third gear 90 mph and fourth 130 mph,”he says. “Fifth gear had been removed along with reverse, again to save weight. First gear was used only for tyre warming, starting for the timed runs being conducted in second gear.”With such a limited budget, it made sense to use not only the gearbox but as much of the other Ford Sierra 4×4 parts as possible, including the transfer box. Using the standard epicyclic transfer gear train and viscous coupling, drive to the front goes under the heavily-canted engine and up to the Lotus Elan-derived differential housing before cascading out either side, through the inboard ventilated disc brake arrangement and out to the modified Golf GTi Mk 2 front uprights. The brake discs, being inboard, are limited in diameter to 260 mm because of ground clearance considerations but with AP Racing 4 pot calipers, retardation isn’t an issue. At the rear, drive was much like the front with yet another 3.9:1 Elanbased diff, complete with limited slip differential, feeding the drive through a pair of Ralt RT32 rear uprights acquired during the protracted 10-year build. With all these shafts whirling around and the requirement to mount extra differentials and turbocharger units etc, Mann erred very much on the side of safety and fabricated the spaceframe chassis out of predominately 11/8-inch by 18 swg (1.22 mm) CDS tubing. Although the car had never been weighed properly, all up weight is estimated at “a rather heavy 650 kg,” Mann wistfully reported, with the target 50:50 front-rear static weight distribution.
There was scope to significantly reduce weight by rationalising gas turbine and fuel system parts as well as those in the transmission but only when funds allowed. Perhaps the biggest effort required in any home-build project is that of producing the bodywork. Always a compromise between effort required, weight and cost, the temptation is either to give up totally and hand it over to a professional or invest your own time in the tedious task of making a body buck, taking a female impression of this and then making the actual body out of carbon fibre/GRP. Wishing to eschew both options and using clear engineering logic, Mann’s answer was to make the front and upper bodywork out of sheet aluminium while the sidepods, incorporating the cooling system on one side and the turbocharger and oil tank on the other, were made out of 3 mm birch plywood. Carpenter Mann explains: “Although I was limited to 2D curves, the panels are bonded together using pinewood strips and coated with several layers of epoxy resin before being finished with a 2-pack polyurethane paint system. The resulting finish is exceptional with only a slight weight penalty over the more normal GRP arrangement.”
Starting the engine(s), as you might expect, was not that simple and is somewhat reminiscent of starting a helicopter. Since the turbocharger oil feed and scavenge system are operated off the main engine, this needs to be running first. Next in the strict sequence of events, the auxiliary gas turbine turbo unit needs to be started using compressed air from the off-board starter unit. At 1 psi boost with the turbo spinning at 10,000 rpm, ignition and fuel (initially diesel fuel held in a separate tank) could be switched on. At 5 psi the system is self-sustaining and the starter unit can be disconnected. At 13 psi with the turbine spinning at 40,000 rpm and the main engine at idle, the system is ready to go. Tyre burnouts are conducted at 13 psi boost in first gear but timed runs, for 2005 at least, used the higher 25 psi boost limit, manually selected from the dashboard. Not surprisingly, there were issues. “Control of the turbine was initially a problem,” he remembers, “with the unit flaming out upon changing gear and losing boost.”
As these were addressed the next problems were more serious and potentially more expensive to fix. Out of the car’s first four meetings – one of which was the Shelsley Walsh Centenary event at which it lowered the hill record for Shelsley Specials by a magnificent half a second – two gearboxes failed. Each time the offending part was third gear on the MT75 gearbox when for the first time during a run the transmission experienced the full engine torque. Examination of those recognisable parts remaining suggested simple low cycle fatigue. In other words, the box was not strong enough! The winter rebuild was focused on improving the strength of the gearbox and reducing the inertia of the driveline. The weight of the propshafts (both front and rear) was substantially reduced by replacing them with TORQline – carbon fibre wound – versions from the Crompton Technology Group. Support in the form of a 51/2” aluminium triple plate clutch came from Tony Tewson at Superclutch, while a lightweight flywheel and starter motor were supplied by Ark Racing.
After further tests conducted towards the end of the year, further weight was saved by dispensing with the diesel fuel tank and running the turbine on gasoline fuel from the main tank. Along with the adoption of a lighter battery, the car now weighed 25 kg less. The major issue of the gearbox, however, was yet to be resolved. “The original plan was to graft the much stronger Borg Warner T5 gearbox complete with a Glebe Transmissions dog clutch conversion to the existing 4×4 transmission,” says Mann. “Unfortunately, since space is very tight, this wasn’t possible. “Plan B as to fit the T5 gears into the existing 4×4 Sierra casing. Rated at around 450 lbs ft (610 Nm), this should give me enough reserve to increase the boost pressure a little towards the 43 psi maximum – but maybe not this year!” While Mann has completed all the design work and manufactured the new gear linkage, he awaited the new gear parts with relish as the season got ever closer. With a little extra finance from Aldon Automotive, the target was the Gurston Down event at the end of May.