Objet p'art

P'art of the day: NASA Spring Tyre

2010-02-25T23:39:00.001Z

Todays p'art is a tyre developed for lunar hoonage

They're a big step up from the crappy mesh tyres that Neill Armstrong and Buzz Aldrin had to make do with. Each wheel is made up of 800 individual load bearing springs. Unlike regular pneumatic tyres the spring tyre is unaffected by temperature changes and vacuum conditions.

The Tyre is also unburstable. Unfortunately the tyres reliability is entirely dependent on the engineer's hats. They don't just wear them to look good.

Each spring has to be individually stretched. Heres the guy who does it. Apparently his name's Jim but that is of little significance.

P'art of the day: Lexus LFA A-Pillar

2010-02-24T23:04:00.000Z

Todays p'art exhibits robotic craftsmanship at its best

The Lexus LFA is a tribute to over engineering. To construct the A-Pillar Toyota (Lexus' parent company) have one of only two dual tube rotary looms in the entire world! This allows them to construct almost any three dimensional shape seamlessly from carbon fibre.

As if this wasnt impressive enough, by virtue of its dual tube design, it can weave a 3d shape within a 3d shape. This allows the LFA's A-Pillars to be manufactured to a level approaching the theoretical ideal. It allows them to be lighter and stronger than practically any other possible design.

Lexus used similar advanced composite techniques to produce shapes in the body work that simply aren't achievable with metal, such as the air intakes on the shoulders. To finish heres a video of the dual tube rotary loom in action. Oh Lexus pulled the video. Bummer.

P'art of the day: Napier Railton Front Grille

2010-02-23T23:53:00.001Z

The last few p'arts have been pretty technical, so today's is pure eye candy. The Napier Railton was one of a distinctive line of Aero Engined specials designed with one thing in mind, speed.

The Grille was hand made out of a single piece of aluminium and reflects the "Looks right, Flies right" approach to aerodynamics prevalent in the early '30s. Cars like this would bludgeon their way to a land speed record as opposed to glide to it.

The primary tool in this assault on physics was a 24 litre aircraft engine, the Napier Lion. As well as looking epic, the front grille fed masses of cool air the radiator to keep the Lion roaring. The Railton still holds the lap record at Brooklands with an average speed of 143MPH.

The Railton was capable of 168MPH which must have been colourful with only rear drum brakes. Later in its life the Railton was modified for service as an experimental vehicle for testing parachutes. How a 2 tonne car got all four wheels off the ground on a heavily banked course is anyones guess, but it was probably quite exhilarating.

P'art of the day: Honda NR750 Oval Piston

2010-02-22T20:10:00.002Z

Todays p'art was developed for two wheels instead of four.

The oval piston was developed by Honda and first appeared on the NR500 in 1979. Ever the innovators, Honda were determined that 4-stroke engines could compete with the dominating 2-strokes. The Gran Prix bikes were limited to 4 cylinders so Honda used oval pistons so they could use more valves. Each cylinder had 8 valves and each piston had 2 conrods, it was effectively a V8 disguised as a V4.

The manufacturing processes necessary to maintain adequate cylinder sealing were extremely challenging to develop. Unlike normal pistons that can be turned on a lathe to achieve exact tolerances, the oval pistons had to be painstakingly machined. The piston rings were very challenging to produce for similar reasons.

After years of exhaustive development the engine finally developed the target figures. 130bhp at 19500RPM were unheard of for a naturally aspirated 4-stroke 500. Unfortunately due to weight issues the 4-stroke NR500 was not competitive, its only victory being the 500kms of Suzuka in 1981.

However all was not in vain. Honda amassed a vast cache of knowledge about unique manufacturing problems and 4-stroke performance from the project. These days 2-stroke engines are all but obsolete, due to emissions, economy and reliability issues, a testament to Honda's foresight. The Oval Piston engine was eventually used in the NR 750 of 1992. Their determination to pioneer new technologies meant that Honda remain at the forefront of naturally aspirated engine design, on two wheels and four, on road and track.

If you want to be the best you have to take chances, Toshimitsu Yoshimura, an engineer who worked on the original project summed this up well by saying, "When I look back on it, I'm not sure if we were experimenting with cutting edge technologies or obsessed with foolish ideas".

P'art of the day: Turbonique Rocket Drag Axle

2010-02-21T17:46:00.001Z

Todays p'art is probably the maddest aftermarket part of all time. Which is fitting because its the first aftermarket part to be featured here.

Turbonique was quite an interesting company. It was started in 1962 by Gene Middlebrooks who worked as a contractor for NASA's space program. Turbonique was one of those rare companies where pretty much everything they made was unique and original. But the Rocket Drag Axle was their crowning achievement.

Developed as a bolt on part the Drag Axle was essentially a hybrid of a liquid rocket and a jet turbine. The forward end of the Drag Axle replaced the centre of the standard rear differential. Turbines in the rear of the Drag Axle drove a shaft which brought power forward to a takedown gearbox. This shaft attached to the takedown gearbox converted the 60,000RPM at the turbine down to 7200RPM at the diff. This allowed the thrust delivered by the rocket motor to be fed to the rear wheels instead of just pushing the car like a jet engine.

The Rocket engine ran on a liquid called Thermolene. The chemical compostion of Thermolene was N-Propyl Nitrate. It was fairly volatile stuff, it ignited at normal temperature, melted rubber and plastic, was extremely toxic to inhale and reacted (caught fire) if it came into contact with steel or water(!). Despite this the drag axle was somehow road legal, the '60s were cool.

The Drag Axle provided between 850bhp and 1300bhp at the rear wheels while retaining a fairly stock outward appearance. To prove its ability Turbonique installed one in a VW Beetle which was standard other than reinforced suspension, wider rear tires and a parachute. It ran a 9.63 second standing quarter at 168MPH. Surprisingly it was crashed shortly afterwards.

Unfortunately its difficult to be that kick ass without some kind of a trade off. In this case it was that the Thermolene tanks in cars equipped with a Drag Axle (or anything else Turbonique made) would regularly explode, creating a fuel air bomb type explosion that would kill the driver more often than not. Meanwhile its creator, Gene Middlebrooks went to jail over 16 counts of federal mail fraud. This was due to the Turbonique hardware coming in kit form and being advertised as ready to use. Middlebrooks got into financial trouble because he obsessively designed new parts and lost interest in parts that he had already finished. So the fraud charge was more a case of poor business acumen than malicious intent.

These days trying to get regular access to Thermolene usually lands you with arrest under the prevention to terrorism act so the few lucky people who own a rocket drag axle have modified them to run on plain old Hydrogen Peroxide, thats rocket fuel to you and me.

P'art of the day: Chaparral 2J "Vacuum Cleaner"

2010-02-20T22:03:00.001Z

Todays p'art gave the team that invented it such an advantage over the rest of the field that it was banned after 1 season of racing.

The 2J was the maddest in a long line of progressively madder racing cars by Chaparral. It's party piece was a 45bhp snow mobile engine that powered a pair of 430mm fans at the rear of the car. These fans sucked air out of a large compartment below the car. This compartment was sealed from the atmosphere by sliding skirts made of lexan, which minimised ingress of air at atmospheric pressure.

This produced a partial vacuum under the car equivalent to 1/5th atmospheric pressure. As force is pressure divided by area the total downforce produced by this arrangement was about 500kg. This meant that while the engine only had to accelerate 820kg of car the force which forced the tires onto the road was 1320kg. This was also true during braking and cornering which allowed the 2J to lap a few seconds faster than its closest competitors, every lap. (The sliding skirts can be seen above and below)

Unlike typical racingcars which generate downforce relative to speed (an increase in downforce is the square of an increase in speed), the 2J generates nearly all of its downforce stopped because the snowmobile engine runs independently to the main engine. This graced the 2J with prodigious traction during standing starts, allowing the full might of its 700bhp engine to be unleashed with negligible wheelspin off the line.

Despite being far faster in qualifying and racing in general, it suffered from reliability issues, mainly overheating of the fan engine. These problems could have been solved through development over the course of the following seasons. Unfortunately the competition didn't like being hammered and complained about the use of the fans, saying that they were "movable aerodynamic devices" which were outlawed by the FIA although the car had already been approved. There were also claims that the fan threw up debris on the track, but these were largely unsubstantiated.

P'art of the day: Maserati "Birdcage" chassis

2010-02-19T19:58:00.005Z

Todays p'art is a tribute to Italian racing pedigree of the late '50s and early '60s, the reason the Maserati Tipo 60-65 were nicknamed "Birdcage"

While the majority of racing cars from the era used sheet metal "tub" chassis of steel or aluminium the Birdcage utilized a spaceframe chassis of cro-moly steel. Chrome Molybdenum Steel is a metal with an excellent strenght to weight ratio. It is typically referred to as aircraft tube as its used extensively in aviation. Its also used in AK-47 recievers.

The Birdcage was consructed from over 200 individual tubes, between 10 and 15 millimetres in diameter. The beauty of this construction is that because all the tubes are joined at their ends, they only experience tension or compression, forces that tubes are highly efficient at taking. With no bending forces to worry about the engineers could specify an extremely thin wall thickness, further lightening the overall structure.

However there's no such thing as a free lunch. The reason the Birdcages adversaries used a tub design was due to the complexity of the spaceframe. Every point one or more tubes met had to be welded very carefully to prevent undue stress. The welder had to fuse the periphery of every point of contact evenly so as to simulate the "end point loading" which prevented any bending occuring.

The fruit of Maserati's labours was a car that only weighed 570kg in the original Tipo 60 and 600kg in the most famous birdcage of all, the Tipo 61 (Above). Despite their avant-garde construction and high revving aluminium enginesthe Birdcages never won at Lemans due to reliability issues, however theTipo 61 won the Nurburgring 1000km in 1960 and '61.

The Tipo 64 and 65 used an evolved version of the chassis constructedfrom a greater number of tubes of even smaller diameter. These werenicknamed "Supercages". The Tipo 65 Supercage (Above) was equipped witha 430 bhp 5 litre V8, but it still only weighed 840kg and was reputedlygood for 217mph, which in 1965 with contemporary safety systems and no roof must havefelt very fast indeed.

P'art of the day: McLaren F1 Engine Cover

2010-02-18T23:04:00.002Z

Todays p'art puts neither form nor function first achieving both simultaneously. When it was released the McLaren F1 was an exercise in superlatives, retaining the titles of the fastest, most accelerative and powerful production car for over a decade.

The design brief was that each component had to be made of the best materials available for the application. This brief was followed to an almost obsessive level by the engineers under the guidance of the prodigious Gordon Murray.

To this end when it was realised that the carbonfibre monocoque chassis would suffer from extreme heat soak due to the inboard exhaust system (see above) a suitable heat dissipater had to be found. In keeping with the brief the chosen material was the best heat reflector known to man, 24 carat gold.

In all, 25g of pure gold foil were used to line the engine bay. The McLaren F1 was one of the quintessential icons of engineering integrity without pandering to the accounting department, the likes of which may never be seen again.

P'art of the day: Ford GT40 Door

2010-02-17T22:27:00.005Z

Today's p'art is the cutaway door from the legendary 60's Ford GT40

In 1963 Ford entered into negotiations to purchase Ferrari so as to take advantage of their racing pedigree, however Ferrari backed out at the last minute. Having spent millions of dollars investigating Ferraris assets to make an informed bid, Henry Ford II wasn't a happy camper. Ford called his motorsport division and told them to beat Ferrari at his own game.

The cutaway roof section of the door is what makes it special. This was necessary due to a unique problem that le mans presented. The "le mans start" was a tradition in which the drivers lined up against one wall and the the cars lined up against the opposing pit wall. On "go" the drivers had to run across the track to get to their cars. To get away as quickly as possible the drivers wouldn't put on their safety harnesses, doing them up when they could a few laps in, or not at all. Due to the high sills on the racing cars getting in through a tiny aperture into a cramped cockpit was a skill in itself but the with GT40 doors extending almost to the centre of the roof, the driver merely had to stand on the seat and slip into position.

Heres the famous "le mans start" from 1966 notice the GT40 in the foreground, despite teething problems in 1964 and '65, Ford was on top form in '66 with the GT40 Mk II. They came 1st, 2nd and 3rd that year and won at le mans the following three years. In 1969 Jacky Ickx decided to boycott the running start, casually walking to his car, nearly being hit by a front runner in the process and carefully securing his harness before driving away in last place. John Wolfe was subsequently killed in his porsche 917, he hadn't used his harness, while Ickx went on to win. As a result the Le Mans start abandoned from 1970 onwards.

Heres a clip of the 1966 Le Mans start, sorry about the german narration, it isn't much crack.

P'art of the day: Mercedes F400 Carving Steering System

2010-02-16T19:02:00.001Z

The p'art of the day is the variable camber suspension/steering from the Mercedes F400 Carving prototype

To fully appreciate todays p'art a basic understanding of car cornering dynamics is useful.
As a car turns the majority of the cars kinetic energy is transferred to the outside wheels. Because the cornering load is quite substantial the bottom of the wheel tilts inward towards the car (as below) and the load moves to the outside of the tyre. The inside of the tyre meanwhile has little or no load and therefore cannot contribute to lateral grip, in extreme cases the wheels tilt can cause the inside to not touch the road at all. This causes the outside of the tyre to wear more quickly than the inside and really degrades cornering grip and speed.

The solution is to set up the suspension with negative camber. This means that the bottom of the wheel leans outwards when the car is not cornering. The aim is to have the outside wheel completely vertical when its loaded up during cornering so that the load is equal across the tyres contact patch. However the downside is that negative camber causes the insides of the tyre to wear while the car is going in a straight line and and any given negative camber angle is only optimum at a certain cornering speed and steering angle (A typical fast road camber setting is around 1.5 - 2 degrees negative), as is often the case a compromise has to be made sacrificing optimum grip for acceptable wear or vice versa.

This is not the case with the F400 Carving

The Wheel hub is attached to the chassis via a pivoting link and a hydraulic cylinder. This allows the negative camber to vary constantly adjust between 0 and 20 degrees depending on what the car is doing. The camber is controlled by a computer that takes speed, steering angle and lateral g-forces into account with various sensors and decides what camber angle is appropriate. Such is the advantage of modern computing this all happens rather quickly. This system caused the vehicles cornering g-forces to increase by 28% over static camber which in a modern car is mind boggling.

This prototype also spear-headed the development of asymmetric tyres which brought tyre technology on in leaps and bounds. The only downside to the possible use of active camber systems in future road cars is that the brilliant stances that static negative camber can give a car may be a thing of the past, as on this Milliken 'Camber Car'

P'art of the day: Bugatti Aerolithe Bodywork

2010-02-15T18:28:00.003Z

Today's p'art isn't actually a single part however it's the first featured that epitomises all 3 properties that define p'art; exotic material, brilliant craftsmanship and aesthetic beauty, so we'll have to let it slide.

The Bugatti Aerolithe was first unveiled in 1935 at the Paris motor show. While the aerodynamic swoops and 3.25 litre straight 8 engine drew admiration, the real talking point was Bugatti's choice of material for the bodywork. The body was entirely handmade from Elektron, a Magnesium-Aluminium alloy which at the time was so advanced and expensive as to be reserved for critical aeronautical components. The thought of using it for a production car body was beyond belief.

Elektron is 90% magnesium which is the lightest structural metal. However magnesium is also extremely volatile, it will react with water at room temperature, so the other 10% of the alloy consists of aluminium for chemical stability. For this reason welding was out of the question so an alternative joining technique had to be used.

This led to the prominent dorsal flange, which was riveted along its entirety, a construction method borrowed from aviation. these flanges also feature on the bonnet and along the front and rear wings. The aerodynamic rear wheel spats were bolted on for convenient wheel removal.

This necessity for unconventional construction led to the car being the pioneer for longitudinal fins in car design, inspiring post war icons most notably in america. It also augmented the cars high speed stability

Unfortunately the the Aerolithe's greatest strength was the reason for its downfall. The elektron bodywork was deemed too expensive and too unstable, when it was realised that a crash could lead to instant 1300°C immolation, potential customers feared that the Aerolithe might live up to its latin derived name meaning meteorite. The design and construction techniques weren't wasted however as they were adopted by the conventional aluminum bodied Atlantique Type 57 (shown above) arguably one of the most graceful cars of all time.

The only Aerolithe ever produced disappeared in 1939 during the onset of the war. This rarest and most influential of cars was never seen again.

P'art of the day: The Brakes from the NAE LSR

2010-02-14T17:09:00.009Z

Todays p'art really is 'State of the p'art'. Unlike regular brakes which create friction between surfaces that are forced together to bring a vehicle to a halt, these brakes operate without contact between the braking surfaces

Instead a large circular Neodymium Iron Boron magnet (the black disc above) is held stationary and a metallic conductor, in this case aluminium due to its low density and good conduction (the finned silver disc) is fixed to the wheel so that it spins while the vehicle travels

When the vehicle needs to decelerate the magnet disc is moved close to the conductor disc, by a hydraulic actuator, without actually touching it (as above). The relative movement of the discs creates eddy currents between the discs. These eddy currents create an opposing electromagnetic force in the conductor which works against the spinning of the wheels and slows the car down

The advantage of this system is that because there's no contact friction and the braking force is a product of the relative speed the brakes are unlockable. If the brakes locked the wheel would stop and there would no longer be any eddy currents.

Interestingly the conductor does not have to be magnetic (Aluminium isn't magnetic) it just has to be able to conduct electricity. Apparently at 800MPH (the target top speed) The brakes generate 4700bhp of braking force, but the forces associated with using them at that speed are so considerable that the system can only be utilised at 400MPH and below.

Due to the unique nature of todays part it would be appropriate to look briefly at the vehicle its been designed to stop. The tastefully named North American Eagle is a bit of a strange bird...

It's actually a Lockheed F-104 Starfighter with the wings cut off. Compared to previous modern LSR attempt cars the bugdet for this project is extremely low.While a small team of experts and enthusiasts building a grassroots, 'backyard special' land speed record car sounds like the premise for a bad movie, the fact that its actually happening in real life is pretty cool.

Coupled with the fact that its based on a plane from the 50's that in its day got nicknames like 'The Missile with a Man in it', 'The Widowmaker' and 'The Flying Coffin' (Canada lost 50% of their F-104's to accidents), It's pretty badass...

...Apparently they're still looking for a driver.

P'art of the day: Citroen Hydropneumatique Suspension

2010-02-13T14:57:00.009Z

Today's part was first used on the rear of the '54 Citroen Traction Avant a real contemporary engineering tour de force, the hydropneumatic system achieved major recognition in '55 when it was used on all four corners of the Citroen DS, a timeless design icon

The Hydropneumatic designation hinted at the innovative operation, instead of using regular steel springs the car was suspended by pressurised oil (hydro) and gas (pnuematic).

While the part itself has no remarkable aesthetic qualities the grace with which it operates is breathtaking, the advantages of the hydropneumatic system were two fold, phenomenal bump absorption, allowing the car to glide across uneven terrain... (As this rather abstract period advert demonstrates)

.. and a self leveling effect which allows the cars attitude and ride height to remain unaffected by static loads (passengers, luggage, etc) and dynamic loads (cornering forces, acceleration and braking) even in extreme cases which would really perturb conventional suspension systems, as illustrated in this excellent 70's Citroen GS ad

P'art of the day: Honda RA 273 Exhaust Manifold

2010-02-12T21:06:00.010Z

The first ever p'art of the day is the exquisite exhaust manifold from the Honda RA 273

Exhaust Manifolds are generally good looking, especially on high output N/A multi cylinder engines but the manifold and collector arrangement on the '66 - '67 F1 entry by Honda is a hard man to beat

The exhaust manifold's basic purpose is to transport exhaust gases out of the cylinders and away from the car, but in this case the exact length, shape and collection point (where the pipes meet) all effect the overall resonance of the system which if correctly tuned can scavenge leftover exhaust gas to maximise volumetric efficiency, in some cases to over 100%.

A few different configurations were tried throughout the season although each is beautiful in its own right

No wonder it was nicknamed the snakepit

(the silver bits on the end are just to stop potential dragoning, who could resist)

Objet p'art

2010-02-12T15:18:00.035Z

Welcome to Objet p'art

Objet d'art is defined as a small object of artistic worth

Objet p'art is a tribute to car parts that due to the innovation of their design, the efficiency with which they operate or just their aesthetic beauty can affect certain (albeit odd) people in a way normally associated with artThe aim of Objet p'art is to honour the engineering expertise, the craftsmanship and the artistry of the people who design and make these parts

This will be achieved by featuring a new part everyday and arguing why it should qualify as an objet p'art by explaining its merits be they construction, use of material, operation etc

Any criticism, constructive or otherwise is welcome but keep in mind that this is a purely subjective endeavor and that beauty is in the eyes of the beholder

Hopefully as the project progresses a well rounded archive of p'arts will start to take shape with everything from pioneering late 1800's steam power to state of the art hydrogen fuel cell technology, from Tokyo to Detroit to Modena and everywhere in between, from original equipment to aftermarket parts and one off customs, Road cars to Le mans prototypes and rally raid specials, shouldn't run out of material any time soon...