The challenge: build the fastest motor racer that is humanly possible.
The teams have to build the fastest motor racer possible. Three races down a 100m (330ft) dragstrip at the Avon Park Raceway, near Stratford upon Avon, will determine our winner. Combining maximum acceleration with a lightweight design could be the secret to success in the Scrapheap grand final.
Dick, Bobby and David Strawbridge (lieutenant colonel, major and captain respectively) are three brothers from Northern Ireland. They were blasted out of Scrapheap Challenge last year by the Chemical Brothers in target practice with their home-made cannons. The three soldiers, who have seen action in many of the world’s trouble spots, returned this year to defend their honour – and did so decisively against the Mothers of Invention in the last quarter final (Bridging Machine), against the Techno Teachers in the second semi-final (Giant Mower) and, ultimately, against the NERDS in the series final (Fireboat).
Now these military siblings have to face a trio of distinctly 'different' opponents. Will army discipline triumph over free-wheeling weirdness?
Winners of last year's series final, the Megalomaniacs are Nosh, Kev and Daz. Team captain is tattoo-covered Nosher, who's into scorpions and making his own jewellery. By day, he's a prototype sheet-metal worker – a panel-beater to you and me – and by night, he's a Royal Arch Druid of the Ancient Order of Druids. He's ably abetted by security officer Darren Cross. Darren is into motorcycle drag-racing, and prefers tattoos to jewellery and so has his wedding ring tattooed on his finger. Third member of the Megs is mechanic Kevin Chaplin. When he's not under the bonnet of his HGV lorry, he spends his time medieval sword-fighting.
Darren's drag-racing experience will be a definite boon in this ultimate challenge - not quite sure how druidness and medieval sword-fighting will help, though!
Experienced drag racer Andy Robinson also owns a company that builds race cars. He knows the importance of safety, having put his own car (while in it) on its head at 210mph last year – and walked away unscathed.
Brian Johnson is one of the top bike dragsters in the world. Now in his early 50s, he has had a keen interest in motorcycles since he was 15. He has been world champion, in the top fuel motorcycle league, and has held the world record several times.
John Wright has been an engineer, driver and drag-racing publisher and has served on various safety committees.
Neal Davis, retro-inventor and madcap mechanical creator, is one of Britain's finest hands-on engineers. He built up his experience in the RAF in a career that saw him service fighter planes, defuse bombs and eventually teach engineering. He has since turned his hand to many things: jet-powered tractors, remote-controlled steam engines and shoe-horning big engines (we mean really big – from planes!) into tiny cars. He has even built a machine that parks his car for him! Oh and, yes, he has built a walking machine, too!
Back-to-basics bodging.
This is the story of the contest between two Scrapheap Challenge heavyweights. On one side are the winners of the 2000 series, the Brothers in Arms. On the other, the 1999 winners, the Megalomaniacs. The challenge is potentially dangerous, so the teams will have to incorporate safety modifications into their vehicles.
A delicate balance.
The Megs decide to opt for a trike design against the more traditional dragster that the Brothers plan to field. Thus the heavyweight bikers are going for the lightweight option. The old Scrapheap motto – 'Power-to-weight ratio' – really comes into its own in this challenge as the teams tread a delicate balance between brawn and lightweight materials.
The Brothers plan to use double rear wheels to increase the rubber surface area in contact with the track. Meanwhile, the Megs manage to find a whole working bike on the heap – surely a Scrapheap first?
Colonel Dick commands his Brothers to find the biggest engine on the heap, and David duly returns with a monster V8. Despite the fact that it's ten times bigger than the bike engine they unearthed, the Megs are nonetheless happy with their 40hp effort.
The Brothers’ expert Andy Robinson conducts an olfactory analysis of the oil in their scavenged engine. Apparently, if it smells of toast, it’s good, but if it pongs of charcoal, it’s all burnt out. Andy pronounces the oil to be of reputable character.
The wrong horse.
Judge Neal Davis, veteran adjudicator from Series 1 (Power pullers) and the Series 2 final (Walking machines), the noisiest and slowest challenges so far on Scrapheap, is now the umpire for the fastest. His money is on the Megs – but, remember, he backed the wrong horse on both previous occasions! Whether or not Neal’s patronage is a bad omen for the Megs remains to be seen, but the teams’ engines are certainly well matched in terms of the weights of vehicles they have to power.
The Brothers decide to get their axles from a postal van. These are heavy in comparison to the light Mini wheels that Kev of the Megs has found for their trike. The Megs decide to build their own rear axle, and for this, they find good bearings to go with some strong pipe.
Dick is worried about the coupling between the Brothers' drive shaft and motor. Cathy is worried that their dragster is just too heavy. The Megs are ever so slightly worried about their weight, too, and start to shave bits off their already very light vehicle. Actually, they are quite cocky, sure that they will beat the Brothers, despite allegations that one of their number has gone soft: Kev has just become a father, the baby named 'Stella' after the beer ...
With half the day gone, the Megs have half a bike, whereas the Brothers have a heavy engine and axles but no chassis for their six-wheeled monster. Soon, however, they find some heavy metal section from which they plan to fashion it.
Wobble.
To get the Megs' chain drive working without any wobble coming into the design at the sprocket, captain Nosh devises a mechanism using a mounting template – some very delicate and precise engineering. The Megs seem very serious about retaining their champions’ crown.
Captains Dick and Nosh have a conference at the throne. Dick gives away some military secrets and Nosh lets slip information about Daz’s bike-racing track record and that he will be their driver. This gives Dick something other than his team’s weight problem to think about – after all, he is going to be in the hot seat against demon dragster driver Daz.
Judge Neal still has his money on the Megs since they have been building light from the beginning. Dick’s dinosaur will have to have enough power to compensate for this difference if it is to have a chance. The automatic gearbox might also be a handicap, muses Neal.
It’s not the winning but the taking apart.
With three hours to go, the Megs find that they had fitted their rear wheels a bit prematurely: their rear axle assembly has to be stripped down to fit the chain and sprocket. Despite this, Cathy and Robert surmise that, in the year since Series 2, the Megs have attended the Swiss Engineering Finishing School as they now work with an hitherto undreamed of level of finesse, even doing mathematical calculations like the NERDS.
The Megalomaniacs fit a wheelie bar to their trike to prevent it flipping at the starting line. Much to the shared surprise of scrutineers Robert and Cathy, they find the Megs’ measurements to be millimetrically perfect. The Brothers are, meanwhile, adding even more weight with the mounts for their heavy V8 engine. They also sort out the brakes, steering and safety cage. But when they actually come to start their engine, it doesn’t want to cooperate – despite earlier passing expert Andy’s ‘toast not charcoal’ smell test!
The Megs have spent nine hours sorting out the rear end of their trike and now find themselves with only one hour to finish the rest. Their 'to do' list includes: fixing the seat; attaching the roll cage; sorting the harness; and connecting the brakes.
With just 30 minutes to go, the Brothers get their V8 growling. There is, on both sides, the customary frenzied welding and showers of sparks right up until the end, but of course, everything comes together in time.
Brake-fast of champions.
A large crowd of Scrapheap alumni come to cheer on the teams. This is, in many ways, a dream contest for any Scrapheap team to be involved in – it’s old school, back-to-basics, big block bodging at its best. Neal still has his money on the Megs, but thinks that both machines are now quite evenly matched.
The teams must complete the eighth-of-a-mile course in the fastest time. They are racing the clock, not each other. This means that, even though one team might cross the finishing line first, the other team could still be in with a chance.
In the first of three heats, Dick stalls on the line, leaving Daz to complete the course alone. He manages 11.2 seconds reaching 61mph, which, as Neal rightly observes, is incredible for a scrap machine.
The Brothers’ engine is OK, but that automatic gearbox has come up to bite them in the rear. Only the reverse gear still works, so Colonel Dick does the only sensible thing and elects to do a run backwards up the track. He manages a respectable 19.7 seconds at a top speed of 30.9mph.
Sportsman-like spirit.
The Megs are almost as disappointed as the Brothers as they want a proper race. Someone from the crowd – Si Holder, the Driller Thrillers’ expert from Series 2 (Land yacht) – suggests that the Brothers rotate their rear axle so that they will get forward thrust – a plan so simple, it must be good. The Megs even lend their expert, Brian, to the beleaguered Brothers to get things sorted. With such a sportsman-like spirit in evidence, these teams certainly deserve to be competing for the title of champion of champions in Scrapheap Challenge 2000!
Round 2 sees the Megs reach 61.3mph in 11.14 seconds, whereas the Brothers manage 11.49 seconds and achieve a top speed of 48.8mph. Going forwards in reverse seems to have reversed the Brothers’ fortunes, and Driver Dick streams away from the start ahead of the Megs. Daz catches up, though, but it is very close indeed with only three-tenths of a second in it.
Brian gives Daz a tip for Round 3. As he accelerated at the start, the trike bounced, losing some of that all-important traction. With everything to play for, Brian suggests that Daz 'get it up there on the last one; hold it there screaming,' meaning that Daz should open the throttle fully and drop the clutch rather than accelerate from a standing start. As for the Brothers, they are reaching maximum speed half way up the track with no higher gear to change into.
Cracking speed.
As Round 3 approaches, Daz comes bounding up to the line, revving the trike for all it’s worth, determined to beat his previous times. As the 'Christmas tree' starting lights signal green for 'Go!', both machines fly from the line. Again, the Brothers in Arms take the early lead but, this time, maintain it until the end.
Since the teams are not racing one another but the clock, they have to wait for the computer to decide who has won. Even the driver duo of Dick and Daz are unclear about who has done it. Accompanied by Cathy, they approach the scoreboard simultaneously.
The Brothers have raced spectacularly with a time of 11.5 seconds and a top speed of 48.44mph. However, Daz got the Megs' trike up to a cracking 60.8mph and takes the race and indeed the cup with a time of 11.2 seconds. As Millennial champions of Scrapheap Challenge, the Megalomaniacs will be able to keep their trophy for life.
Be sure to reserve a seat in front of your telly on Sunday, 17 December at 5.30pm to see the Megalomaniacs defend British pride against the winners of the American version of Scrapheap – Junkyard Wars.
The challenge: build the fastest motor racer that is humanly possible.
Pros.
Cons
Pros.
Cons.
What is horsepower?
The 18th-century engineer James Watt invented the term 'horsepower'. He was working with ponies lifting coal at a coal mine and needed to find a way to talk about the amount of power these animals could produce.
According to Watt's calculations, one horse is able to do 33,000 'foot-pounds' of work every minute. For example, in one minute a horse exerting one horsepower can raise 330lb (150 kilograms) of coal 100 feet (30 metres), 1,000lb (450kg) of coal 33ft (10m) or 1lb (0.45kg) of coal 33,000ft (10,060m). For greater distances, as in the last example, a block and tackle needs to be used, with an arrangement of pulleys to trade weight for distance.
Horsepower, torque and car engines.
A car engine produces torque. When petrol ignites, the mini-explosion pushes on the engine's piston, and the piston exerts pressure on the crankshaft, making it turn. As a result, the crankshaft feels some 'foot-pounds' of torque, or turning force. To move a heavy weight, a lot of torque is required, and acceleration from a standing start is provided by torque.
Torque is affected by the area of the piston face, the amount of pressure that the ignited fuel exerts on it and the distance the piston travels on each stroke. In addition, the larger the crankshaft's diameter is, the bigger the lever arm will be and the more torque there will be.
There is a direct relationship between horsepower (hp) and torque. This can be expressed as:
hp = torque x rpm / 5,252.
High values of revolutions per minute (rpm) favour horsepower. Any engine run at very high revs will generate lots of horsepower - even if its torque stays constant. But if two engines produce the same torque, the one that can do it more times per minute does more work and therefore has more power.
How can car engine horsepower be increased?
More power or more torque?
Power is work done – how much is moved how far and how soon. Top speed is determined by power, or the number of torque strokes that can be produced in an engine in the shortest time. If you were to draw up a graph of power output plotted against revolutions per minute (rpm), you would see the power rise with the increasing rpm.
In a trike, less torque is used because there is a lower mass to move. A car, because it's heavier, needs a lot of torque and power, and for drag cars, this is essential. The art of the engine builder is in tuning the engine to adjust the power and torque curves to best suit each application.
What is car transmission?
Cars need transmission due to the design of their engines. Every engine has a maximum rpm value above which the engine can't go without exploding. Also, engines have narrow rpm ranges where horsepower and torque are at their maximum.
Gears are shifted so that the engine can stay near the rpm of its best performance. The transmission allows the gear ratio between the engine and the drive wheels to change as the car speeds up and slows down.
The transmission is connected to the engine through the clutch. The input shaft of the transmission turns at the same rpm as the engine. A five-speed transmission applies one of five differential gear rates to the input shaft to produce a different rpm value at the output shaft.
The best transmission is flexible enough in its ratios so that the engine can always run at its single best-performance rpm value. This is the principle behind the continuously variable transmission (CVT), which has a nearly infinite range of gear ratios.
Both the teams will want to maximise their power-to-weight ratio: for each kilo of the vehicle, they should have as much horsepower as possible. So in general, both teams will want to: find as powerful an engine as possible, make their vehicle as light as possible and get the power to the wheels as efficiently as possible.
One team could build a relatively heavy car with a more powerful engine. The other team could build a relatively light trike with a less powerful engine.
Car.
Cars these days don't have chassis, so the team will have to go for a pick-up chassis. Stripping a pick-up down to its birthday suit isn't as straightforward as one might think and can take quite a lot of time. A pick-up chassis will be heavy, so the team will have to find ways to make it lighter. They may end up drilling holes in it ... taking care not to break it!
Trike.
It is extremely unlikely that there will be a trike chassis available, so the team will have to build one that is both strong and light. That's quite a big job. Apart from finding the right bits for the chassis, the team will have to get their geometry right; otherwise, if they've done their sums wrong, the crucial skeleton of their vehicle could break or the various parts might not even meet up. Despite the work, the big advantage these guys will have is that their chassis will be really light.
Car.
To make up for the extra weight of their chassis, the team will need to find a really powerful engine – something with about 140 horsepower (hp). The engine should be as far back in the car as possible – the more weight on the back wheels, the better grip they will have and the faster they will accelerate the car. But because the team will be modifying a car and not building a new one, the engine will have to go in front of the driver, who will now sit on top of the rear axle. The power of the engine will reach this through the prop shaft. But because the team will be moving the engine towards the back, a normal prop shaft will be too long. They will have to cut a bit out of the one they find and weld it back together.
Trike.
Because the team will be building a lightweight vehicle, every bit of power will go further. As a result, they will be looking for a less powerful, but lighter, engine (about 70hp), such as a motorbike engine. They will have to use a chain to get the power from the engine to the back axle. But they will have a problem: how are they going to attach the chain to the axle? There are no axles with sprockets on them, so they will have to create something. In the lightweight solution, every kilo will have a big effect on the performance of the car, so it will be really important to get as much weight towards the back of the trike as possible. Because the engine will be small and the power transmission will be via a chain and not a prop shaft, the team can put the engine behind the driver. This also means that they can use a short chain, with its strength advantage.
Front tyres.
These are used for balance and steering. Both teams should go for relatively small, narrow tyres that will produce as little friction as possible when they turn.
Back tyres.
Because these provide the power, the teams will want theirs to create as much friction as possible so a maximum amount of power can be transmitted from the engine on to the road and so push the vehicle forward. But just making the tyres bigger (in diameter) will affect gearing, so for more friction, they should try to find wide, bald tyres.
Car.
The team will be limited simply by what they can find. The axles they will be using will already have wheel hubs fixed on them, so the team will have to use wheels that match the stud pattern on those hubs. Therefore the types of axles they find will determine the size of the tyres and the wheels. They will have a choice if the scavengers find what they need.
Trike.
The front tyre will be a fairly simple matter – the team will just have to find one that fits their front forks. As for the back tyres, if they go for a bodged axle, they can pretty much chose which wheel hubs they can fit on it. If they can, they should go for small, wide tyres.
Car.
The team will simply use the brakes they find on the axle they use. The steering needs to be as simple as possible, and so if one can be found, a steering box would be ideal. Old and rarely used today, this is a sort of magic black box of steering. The guys will also have to steal a throttle from somewhere and make up some sort of pedal.
Trike.
The front forks will give the team their front brakes, but the boys will have to steal a disc brake from somewhere and attach it to their rear axle – pretty unorthodox but it should work. With only one wheel at the front, steering will be pretty easy. The throttle and clutch should cause no problems as they will come with the front forks.
The History of Drag Racing in the UK.
members.aol.com/Trakbyte/index.html
Detailed history of drag racing in the UK, with regular updates by racers and fans.
European Top Methanol Racer's Association.
www.etmra.com
Great site on European drag racing, with information about the teams racing top methanol cars, dragsters and 'funny' cars. It also offers news, views, contests and a comprehensive links page.
The Drag List.
www.draglist.com/
A US drag-racing site with articles about the sport plus comprehensive lists of links and books.
The Speed Record Club.
www.soft.net.uk/speedrecordclub/
This site offers news and information on every sort of speed record imaginable, be it on water or wheels or in wind.
Avon Park International Racers Association.
eurodragster.com/apira/
Website of the Avon Park Raceway where Scrapheap tested its dragsters. It contains diary events and articles about the sport.
Santa Pod.
www.santapod.com/
Website of the main UK drag strip, listing events and information for the enthusiast.
Smax Smith.
www.smax.co.uk/
This site by racing star Smax Smith gives racing dates and downloadable press cuttings of his exploits on the circuit.
Close window to return to graphics version.