The challenge This week’s Scrapheap Challenge is a test to see who can build the most extreme rapid-fire arrow launcher. The teams will have to build a projectile launcher that can automatically load itself, as well as quickly firing arrows far and accurately. Stage Crew The boys from behind the scenes! Our Bristolian bodgers Pup, Denzel and Jet are responsible for contraptions used in shows such as Jesus Christ Superstar, Mary Poppins and Miss Saigon. Passionate, animated and enthusiastic is the only way to describe them. Captain Pup’s eyes light up when he talks engineering and he is supported by the bearded Denzel with his hearty laugh and Jet, so-called because of his love for jet engines. This team is used to the pressure of having to perform and with their ‘The show must go on’ attitude, is unlikely to disappoint. The Stage Crew’s expert is a friend of the show, Tod Todeschini. Tod began life as a kitchen product designer but he soon got bored. He is now a medieval weaponry expert and maker of special effects for stage and television. This is his third outing to Scrapheap Challenge and having previously tackled Giant Darts and Rapid Fire, this week's test should be a cinch! The Big Dippers The Big Dippers are Lancashire lads responsible for the maintenance of Blackpool Pleasure Beach. Dodgey (he loves car boot sales and ferreting in skips – should be at home on the heap then!), Steve and Brian (nicknamed Two-ey as he only has two front teeth) have been friends for years and have a wealth of experience. Dodgey comes from a family of mechanics, Steve is the electrics supervisor at the Pleasure Beach and Brian claims to be able to weld underwater. So as well as providing a constant level of cheeky banter, these guys are here for more than the ride! In The Big Dippers’ corner is expert armourer John Nixon. John spent 10 years learning his trade as an armourer with REME (Royal Electrical and Mechanical Engineers), before splitting his time between armoury and mechanics. Nowadays, he is most likely to be found on a film set making guns for epics such as Black Hawk Down and Saving Private Ryan. Let’s see if he will save the day for The Big Dippers! The judge Our judge this week is another Scrapheap veteran, Steve Ralphs. Grand Master of the Traditional Bowyers Guild, Steve began crafting traditional bows and arrows 25 years ago. He now spends most of his time instructing Hollywood actors in the art of archery (this is the man that taught Legolas how to draw a bow). When he’s not doing that he plays guitar in a band called Phabulous Fondue!

The teams each have to build a machine capable of demolishing a set of industrial outbuildings at an old power station in Norwich. Sadly, no explosives are allowed, but they manage all the same. The Beach Boys, a group of twentysomething surfers, decide on a straightforward, human-powered battering ram, and do something no other team has ever managed — they finish building before time is up. The Chaos Crew keeps the Junkyard Wars tradition alive, with a great, big, nasty-looking machine. They build a big hydraulic claw that can rip down walls.

This week's mechanical migraine promises to be a Scrapheap classic. The teams must build contraptions to throw a 100-kilogramme scooter as far as they can, without the help of compressed gas or gunpowder. The Balloonatics, a trio of hot air balloonists from Liverpool, take on The Aquarium Crew, a team of aquarium constructors from Dorset.

Brothers in Arms go up against the winner of Bomber (3 Revs a Minute or Mothers of Invention) in a challenge to build a vehicle that can carry all four members across a 30-foot ravine. The vehicle must also be capable of both deploying a bridge and retrieving it once the team is across. The Brothers go for a van-based bridger, while their opponents use bikes.

In this episode the two teams must make powers boats from the scrap.

Two teams have reached the final and now they have just ten hours to build a tow tug capable of pulling a 155 ton jumbo jet along.

The teams are challenged to build super snow shifting machines as well as having to race up a ten-degree slope in temperatures of minus four degrees.

Inspired by the sleds used to test supersonic planes and spacecraft, the teams are challenged to build a superfast railway... but all usual forms of propulsion are banned.

To get the series off to a smashing start, the first episode challenges the teams to break one of Scrapheap's longest-standing records. Back in series six, The Catalysts set a top speed of 72mph in the Grand Prix Challenge. Now The Rocketeers, a team of pyrotechnicians from Bath, and The Brum Brums, motor mechanics from Birmingham, are challenged to beat that time, in the scrap speed record attempt. Where better to do it than historic Pendine Sands, the spiritual home of British land speed record attempts? The teams are under expert scrutiny as they attempt to race their way into the 'heap record books - this week's judge is two-time land speed record-holder Richard Noble.

The Coventry wrestlers and the Hammerlocks have to dig deep - the challenge is to build a machine that can dig up as much sand as possible in a given time.

Academics get stuck in a maze This week the teams have been asked to map uncharted territory. The Hammerlocks, a team of wrestlers from Coventry, and the Academics Anonymous, a team from Kingston University, have to navigate their way around a 'hostile environment' in a vehicle with the windows blacked out. The Academics seemed to start well but they had a major problem: they couldn't tell when all four wheels of their bus were off the ground or when the bus was level, and this cost them valuable time. They failed to negotiate the first turn in the 'maze', lost their bearings and crashed into the side or the course. Tension was high as the Hammerlocks took their turn in the 'maze'. They also had problems: their navigational devices weren't reliable. However, they were able to crawl their way around the course using a giant mechanical 'feeler' and eventually made it to within a stone's throw of their target - and into the next round!

This week saw a remarkable comeback by the Martial Mechanics, proving once again that nothing is certain on Scrapheap. The Krazy Karters were quicker over both land and water in the first two rounds although they were certainly helped by the Martial Mechanics' 30-second penalty for crashing. Round three looked like a formality, but then disaster struck the Karters: their craft was caught in a strong crosswind and lost air pressure, making it considerably slower over the rest of the course. Seizing his chance and holding on to both his nerve and his craft, the Mechanics' Jason snatched victory.

The first test of the new series was a closely fought three-round contest. The Barleys won the first round convincingly, but the Munch Bunch stormed to a surprising victory in the second. With everything to play for in the final round, the Barleys were lucky to make it to the finish line: a treacherous mud-hole nearly sank them. The Munch Bunch then had not only to complete the section but to improve on the time set by the Barleys. But it was not to be. Their machine became firmly embedded in the same mud-hole that nearly bagged the Barleys, and they were unable to complete the round. The victorious Barleys will be back in a few weeks.

This challenge is to build mobile cranes to lift and carry scrap down a course to a drop-off point. Each piece of scrap is allocated a points value relating to its weight or awkwardness. The team that accumulates the most points over two 15-minute rounds is the winner.

The challenge is to build a powered craft to negotiate a stretch of white-water river. The craft must be powerful enough to get up the rapids but also have enough manoeuvrability to avoid treacherous rocks and to make a U-turn at the top of the course. Whoever sets the fastest single time in the course of three heats is the winner.

Drag racing. Nothing gets a Junkyard Warrior's blood stirring like sheer speed. In this special match-up, the Season 3 champs go up against last year's winner to see who can go as fast as possible while staying on the ground. The champs go for a classic dragster car, but when their gearbox blows up, they have to flip the back axle upside down, making reverse gear push the car forward. Last year's winners go for a trike, which increases the possible speed, but takes much more precision to build.

There's an acre of wheat to cut and collect. This semifinal Junkyard challenge sends the competitors down to the farm to see who can build the best mower. One team turns a taxicab into a take-no-prisoners lawnmower, while their opponents turn a pickup truck into a harvester. Amid lots of smoke and chugging, both teams' machines "buy the farm." The winning machine is an impromptu scythe made out of a foot of metal.

The Techno-Teachers go up against The Manic Mechanics to see who can harness the forces of Mother Nature and build a windmill to power a machine crucial to life as we know it — a coffee grinder! One team constructs a conventional fan-bladed windmill, while their opponents go for a vertical-axis Savonious rotor. Quick on-screen sketches reveal which is best for which wind conditions. But a half-hour before the competition, the weather services release a gale warning, forcing one team to clip the blades off their windmill for fear of having them ripped off. But at competition time, the wind doesn't get over 2 miles per hour.

This challenge tests the teams' underwater ingenuity as they build a salvage machine from a stockpile of scrap in order to retrieve lost treasure from the bottom of a mini ocean.

In this episode the two teams must make a machine capable of flight.

The challenge is to build a salvage machine capable of raising a Mini from the bottom of a murky lake and park it safely in a car park.

The new series kicks off with our barmiest challenge yet: to build a machine that will fire an ostrich egg as far as possible and bring it back to earth in one piece. The machines must be mobile so that - if the eggs survive intact - they can be wheeled to the landing spot for another attempt. Each team is given three eggs and the winner is whoever has travelled the furthest after three shots.

This week's challenge is to torpedo the opposition. Each team must build re-usable torpedoes that run just under the surface of the water, like the torpedoes used to attack boats (rather than those used to attack another submarine). The teams then have to try and hit wooden 'battleships' in front of each other's launch platforms, taking it in turn to fire. The platforms are 150 feet apart, and there's a rock in the middle which they have to steer their torpedoes around. They will have to hit each other's battleship three times. In the event of both teams being on target with their first two shots, the third and final shot will be a simultaneous shoot-out.

The challenge this week is to build a one-man hill climber. The teams will have three attempts to scale a 360ft slope with a 1:2 gradient. The team that makes it to the top the most times wins. If both teams reach the summit only once, car-rallying rules will apply and the first successful attempt - that is, the successful attempt in the earliest of the three rounds - will be the one that counts.

The teams are asked to build a yacht, but not one for the high seas - a land yacht capable of carrying the entire team. The winners will sail through to the semi-finals.

The teams are challenged to make a walking machine: the winning contraption must carry the whole team and a heavy safe across a haphazard obstacle course.

This time, a team called Filth goes up against the winner of Demolition (Chaos Crew or Beach Boys) to design and build a machine that can throw a rugby football as far as possible using only their own muscle power, so no motors allowed. They have to create something that can store muscle power gradually, then release it in a controlled burst. Filth decides to ignore their expert and creates a huge cross-bow-type machine. The other team decides to pump up an air cannon to shoot the ball. And while the winner can't be revealed, one team captain manages to throw his rugby ball farther than his machine could.

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In the first of the new series, Scrapheap takes to the dusty dunes of a Guildford sand quarry as a team of hot-blooded Lancashire fire fighters take on some nerdy off-road enthusiasts in a battle to build sand-racers that can climb precipitous inclines and dig their way out of the deepest dusty trench.

A brave-hearted bunch of Scottish boffins take on a rabble of right-on rickshaw riders in an epic Scrapheap battle. Following in the footsteps of Barnes Wallis, their mission, should they choose to accept it, is to manufacture machines that can pitch bouncing bombs across water to breach the Scrapheap dams.

This week, Geneva-based expats the Up 'n Atoms face up to the REME Rebels, an all-girl team of army-tank tinkerers in one of Scrapheap's most bizarre challenges to date. Our teams have just 10 hours to build a motorised bowling ball capable of toppling ten-foot skittles on a giant bowling alley.

The Challenge This week's challenge is to build off-road rescue machines capable of lifting a hampered hatchback from a water hazard before carrying it cross-country to the safety of stable ground. With steep slopes to get up and down, sticky bogs to get stuck in and soft, slippery sand to sink into, our teams will operating at the limit of their bodging capabilities. Rough Riders Ozzie Senior, Barry Eastaugh (Bazza) and Jason Lord are three Yorkshiremen who spend half of their lives 20 miles off the coast of Hull on a gas storage platform in the North Sea. Between them, they oversee and run the safety, maintenance and mechanical upkeep of the platform. They have a wealth of mechanical engineering experience ranging from heavy plant machinery to bike and car engines. Barry is a 'guru' of a welder and there's not a lot these boys have not had a go at. The Riders have big characters and enthusiasm to match. Ozzie is a karaoke king and has won many an Elvis impersonator competition (and he is also likely to burst into a song at any given moment). Barry is known for his year-round tan and Lycra shorts. The Rough Riders are guaranteed to rise to any challenge – and they'll probably do it singing! The Rough Riders' expert is Tim Dray. He started out as an agricultural engineer and soon fell in love with off-roading. He has built many an off-road vehicle and has spent a lot of time organising the Camel trophy. Since this period, he has been a consultant to Land Rover, building and designing their 4x4 courses. Bakewell Puddings Nick Marriott, Mark Elliott (Smell) and his nephew Andrew Charlesworth (Charlie) are from the Derbyshire town of Bakewell. All are into bikes and racing (Motor Cross and Enduro). Mark and Nick have been friends for 20 years and have been in the same Motor Cross team as well as in a punk band together. Mark started to teach Charlie to ride at the age of nine, so it's fair to say bikes are this team's thing. Mark Elliott is an engineer, Nick Marriott is an architect and Andrew Charlesworth is a Rolls Royce engine inspector. These guys are also outdoorsy, sporty, rugby-loving, mountain-climbing kind of people who participate in the annual Bakewell raft race and the odd cross-town wheelbarrow race. They thrive on a challenge with plenty of ingenuity and humour to keep us all entertained! The Bakewell Puddings' expert is Steve Matthews and he's been building commercial recovery vehicles for the past 20 years – mostly out of scrap! In the past, he's also renovated tanks. He doesn't like beer, so what does he do to relax? Well, he likes nothing better than a cup of tea and ... building more cars! The judge This week's judge is Simon Buck, the only British winner of the most hardcore of all 4x4 events – the Malaysian Rainforest Challenge. His motto is 'it's better to be a spectacular failure than a dismal success.' He's a gung-ho guy – enough to drive at 70mph through the Malaysian rainforest ... in the monsoon season ... at night. As you can imagine he spends a lot of time getting vehicles out of a tight spot!

The Challenge This week's challenge is to build jet-powered speed boats that are both agile and fast. The teams will be competing in a two-part Grand Prix – on jet boats! The race will start with a full-throttle dash up and down the lake and will be followed by the twists and turns of an off-shore obstacle course. Hairy Hogs Conn Kelly, Darrell Hanna and Alastair Nethercott are the Hairy Hogs from Northern Ireland. All members of the Provincewide Harley Owners Group, they are big blokes with bigger laughs who love their Harleys and spend much of their year touring around Europe on them. The Hogs are seriously hands-on and have had experience of most possible mechanical projects. They are rough 'n ready, rugby-playing, Guinness-loving men who are up for the challenge and in search of a 'good craic'. These guys are quietly confident they can't be beaten and should give even the most solid of Scrapheap teams a run for their money! Apparently, they're up for most things apart from a water challenge (ha!). Alan Pickard is the Hairy Hogs' expert as well as being one of the foremost jetskiers in the UK. He runs Jet Shed, the leading specialist workshop in this field in the UK. Previously seen on White Water Rider (series 4), he is a hands-on bodger and technician and previously held the speed record on a jetski – he is currently ranked number three in the UK. Team Ragbo Glynn Myers, Nick Mellor and Colin Bates all work at Smart Recycling, Glynn's plastics waste-recycling firm in Lancashire. Between them, they have worked on everything from factory equipment and heavy plant machinery to cars and bikes. This team are heavily into their bikes and two years ago Nick sold his house so he could buy a Triumph bike – he now lives in a caravan! There is a wide breadth of experience and knowledge in this team and the guys are confident they can deal with anything we throw at them! Glynn and Colin are larger than life in every respect, with 'Hippy Nicky' being slightly quieter – but he sees himself as their 'secret backbone'. Lots of northern humour, loads of energy and bags of banter – you won't be able to get a word in edgeways! Alex Wallis is Chief Engineer at Pursuit Dynamics and will be Team Ragbo's expert this week. His company specialises in pumps, fluid management and innovative marine propulsion systems using steam power. Alex is a mechanical engineer with a practical background, particularly in the bodging of various automotive matters and he's even built his own sail plane. The judge Michael McDowell works for Polaris UK as their technical man, on hand to answer any mechanical problems in the Polaris Jetski dealership chain. He also trains all sales outlets on the mechanical running and maintenance of Polaris Jetskis. He has been working for eight years in the field of maritime power units, impellers and jetskis. He also has an engineering background in motor mechanics, quad bikes, outboards and even pumps. When it comes to summarising what makes a good jetski, Michael can talk at length about all the key ingredients with consummate ease.

The Challenge This week our teams will have to earn their Scrapheap wings! Norfolk bikers, The Thirsty Knights, and Honda head honchos, The Fireblades, won't actually be leaving terra firma but they will be challenged to build cars that are powered and steered by a propeller! The Fireblades Steve Martindale (Smarty), Chris Barfe (Barfy) and George Wise (Big George) have known and drunk with each other for 10-15 years and work in different divisions at Honda UK. They have a broad span of interests ranging from motorcycle racing, classic cars and Raleigh Choppers to singing rock 'n' roll, Chelsea FC and running marathons! They are confident that between them there is not an engine around that they haven't worked on. These boys like power and speed and as long as it's fast, they don't care what they build! The Fireblades' expert is John Gifford, a Scrapheap veteran who appeared in series 5's Hovercraft. He is one of the UK's foremost hovercraft designers. He built his first hovercraft at the age of 16 and recently appeared in a Bond film as a hovercraft stunt driver. His firm, Griffon Hovercraft, builds vessels for coastguards and the military. The Thirsty Knights Frog Twissell, (yes, that's his real name) Pete Twissell and Carl Verlander (Roo) combine to bring you The Thirsty Knights. Frog is a paragliding Buddhist vegan who likes to play with fire, Pete is a pagan who says he has an empathy with machinery and is to nuts, cogs and engines what Dr Dolittle is to animals and Roo is a welder extraordinaire who claims he can tap dance whilst playing the flute! This team are quirky, alternative and very intelligent. Yet another team who love their bikes, they have owned, built, raced and maintained many over the years. Used to thinking laterally around a problem, they love designing the weird-and-wonderful. Their machine will be a creation in every sense of the word! Billy Brooks is The Thirsty Knights' expert and he's a mad inventor and microlight-flying maniac. Billy is also a Scrapheap veteran, appearing in series 2's Flying Machines as well as Scrapheap's US equivalent Junkyard Wars. His day job is as a microlight designer but by night he can be found living on his barge. The judge Judge Brendan O'Brien holds the world record for holding the most world records in aviation. His day job is a stunt flyer – you don't need a hobby with that on your CV. One of Brendan's future projects includes crossing Greenland on a propeller-powered microlight sled. As you do …

The Challenge Power Rowers Scrapheap goes back to the water for the latest challenge as The Anoraks take on Maximus. In honour of our Olympic oarsmen and women, the two teams have to assemble a mechanised galley with at least four oars to scull their way around our tricky aquatic course. The Anoraks The Anoraks In this year's first episode, The Anoraks poured cold water on The Hoselliers, a team of fire fighters from Blackburn, as they raced out of our sheer sand trap in Surrey. Deprived of their captain Geoff Turtell for their second challenge, The Anoraks are now led by Marc Draper. Lyndon Camidge joins him again along with Andy Cross an old school friend of Lyndon's who comes in as a substitute. Andy is a plant fitter and HGV mechanics expert. Named after their club of the same name, these three enthusiasts from Surrey can't get enough of off-roading. The lads spend their spare time in Marc's garage, building and restoring Land Rovers and other 4x4 vehicles. Lyndon claims he has broken, crashed and sunk more Land Rovers than he's had hot dinners and Marc likes to think he is the stabilising influence of the team. Lots of experience, slightly batty and a bit posh, these boys are determined to go all the way! Rob Austin is The Anoraks' expert this week. He's an engineer and teacher from Oxford who organises the Formula Schools engineering challenge. Rob worked as a professional fabricator and engineer in various fields before going into education and creating a successful engineering course for schools. He now runs Formula Schools, a scheme to get youngsters interested in automotive and maritime engineering. From his well-equipped workshop in Oxfordshire, he builds and fabricates pretty much anything and is currently rebuilding a classic Bugatti racing car. Top Maximus Maximus Our second set of challengers are the rickshaw-riding charioteers Maximus, who bowled over Irn Cru in the fourth challenge of series seven with their barmy bouncing bomb. Cycles and big barges float these Bath-based boys' boats. William Trickett, Paul McGarry and Dennis Mapp work at Cycles Maximus, which makes and supplies rickshaws. William, or Trickett as he likes to be known, is also a boat engineer and has a company which makes luxury Dutch barges. They are into all kinds of cycled contraptions from rickshaws and chariots to trikes and motorbikes. They also share an interest in canal boats – so are used to building things out of the ordinary. They are quirky, alternative, great fun and are phased by very little. Trickett is completely mad, Paul lives on a canal boat and is also a circus performer and Dennis is a Motor Cross rider who, in his own words, will have a go at anything! A great team. Maximus' expert Jim Bond is not an engineer but an expert fabricator and metal-work sculptor. His speciality is mechanised sculptures. He has worked on TV series like The Secret Life of Machines and can easily grasp the concepts behind automating a human movement mechanically. Cool and calm, Jim is used to getting kids motivated about engineering projects but confesses he is a bit laid-back. The judge The judge Richard Carless is a keen rower and has lived and worked on the water all his life. He owns a marine safety business for the film industry and recently worked on the BBC's Building the Impossible: Submarine episode. He is a Guinness Book of Records holder for several rowing endurance and distance records. He recently smashed the long-distance rowing record from the origin of the Thames to the Thames estuary. He knows what it takes to make a good rowing stroke and being a boatman all his life can tie this into both engineering and hull design.

The Challenge Spy Cars The last quarter-final mission, should our challengers choose to accept it, is to build a stealthy 'spy car' for use on a secretive information-gathering exercise. Their reconnaissance vehicle will have to carry the entire team both under and over obstacles which are just two feet from the floor, turn on a sixpence and then back out of trouble. They must avoid detection whilst infiltrating a sinister-looking base protected by guard posts, razor wire, security cameras, alarms and laser beams. Once inside, they must limbo, hurdle, twist and turn their way into (and out of) danger in order to steal a top-secret briefcase before making good their escape. Bakewell Puddings The last time we saw the Bakewell Puddings, they were pitting their wits against Rough Riders, three North Sea gas engineers from Hull, in Off Road Rescue. Nick Marriott, Mark Elliott (Smell) and his nephew Andrew Charlesworth (Charlie) are from Bakewell in Derbyshire. All are into bikes and racing (Motor Cross and Enduro). Mark and Nick have been friends for 20 years and have been in the same Motor Cross team as well as in a punk band together. Mark started to teach Charlie to ride at the age of nine, so it's fair to say bikes are this team's thing. Mark is an engineer, Nick is an architect and Andrew is a Rolls Royce engine inspector. These guys are also outdoorsy, sporty, rugby-loving, mountain-climbing kind of people who participate in the annual Bakewell raft race and the odd cross-town wheelbarrow race. They thrive on a challenge and have plenty of ingenuity and humour to keep us all entertained! John Ricketts (also known as Johnny Nitro) is a drag racer of the classical style à la American Graffiti. He owns, maintains and races his 8-litre 1965 Chevy and has been known to fit a nitrous oxide system to a Ford Anglia. When he's not being a petrolhead, John can be found catching tubes (that's surfing to you and me) off the Cornish coast. Up 'n Atoms Up 'n Atoms reached the quarter finals by bowling over the REME Rebels, three female soldiers from the Royal Electrical and Mechanical Engineers, in Bowling Bangers. Ali Day, David McFarlane and Jimmy Ridewood are expats living the life of Riley in Geneva. They work at CERN (Europe's largest centre for nuclear research) and explain their work as Star Trek-type stuff, experimenting with smashing particles together to see what happens. They're science boffins but not in the slightest bit geeky. They enjoy playing on the slopes of Switzerland, rugby, British sports cars and a good pint or 14. They have a background in off-shore work and have nuclear power station training – so there is an extremely solid engineering skills base here. They claim that James is the 'looks' of the team, Ali is the 'brawn' and David is the 'brains'. Up 'n Atoms' expert is Jim Chalmers, a creator of whacky vehicles. By day he runs a large workshop outside London but he's happiest when he's inventing – most recently he patented what could be the world's smallest commercial hovercraft. He's recently got in trouble with the police for strapping a jet engine to the top of an Escort. Future projects include building a McLaren F1 – for the road! The judge John Hetherington is a veteran of Scrapheap after judging the Minesweeper challenge back in series 4. John is a professor of engineering design at Cranfield University and head of the Engineering Systems Department at the Royal Military College of Science – he's the man who teaches potential Qs!