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Ducati Desmosedici GP9 carbon fibre frame

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April 13, 2009

Ducati Desmosedici GP9 carbon fibre frame

Ducati Desmosedici GP9 carbon fibre frame

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Ever since designer John Barnard built the 1981 F1 McLaren MP4-1 chassis from carbon fibre, the world has become increasingly aware of this novel composite material that is very stiff, three times stronger and more than four times lighter than steel! Within a year or two, carbon fibre became the construction material of choice for F1 designers. Strangely, it has taken nearly three decades for a carbon fibre-framed motorcycle to take a race win at the highest level. The World MotoGP Championship kicked off this evening in Qatar, with Casey Stoner taking the first win on the carbon fibre-framed Ducati Desmosedici GP9. His emphatic win indicates yet another competitive-edge Ducati technology to back up its landmark desmodromic valve-train and traction control technologies.

Unlike its four-wheeled equivalent (F1), where the entire cast at the pointy end of the field has changed, the most likely scenario in MotoGP is another enthralling season-long battle between superstar Italian Valentino Rossi and resurgent 2007 Champ, Casey Stoner.

The technological highlight of the pre-season has been the carbon fibre frame and swinging arm of the Ducati which takes frame technology to a whole new level.

Frames have not been constructed of carbon fibre previously because it doesn't flex enough, and the dynamics of motorcycles have made good use of the frame flex offered by metallic frame construction. As the metal frames have been stiffened, motorcycle race constructors have found that the natural harmonics of the frame material can influence many factors, often introducing wheel chatter and other destabilising vibrations. The harmonics of the frame is responsible for a lot of the problems race engineers encounter while setting up a bike to perform at its optimum.

As carbon fibre construction expertise has grown, and Computer Aided Engineering has given us the computational ability to lay the the angles of the the fibre in such a way that designer qualities can be engineered into a component, carbon fibre has been getting closer to use as a motorcycle chassis material.

In the beginning, its aforementioned qualities of being strong, light and stiff were what made it so attractive to F1 designers – Lotus also fielded a carbon fibre car in 1981, but Barnard's McLaren was a monocoque design, taking advantage of another carbon fibre property - it can be moulded into any shape.

The entire F1 field followed suit within a short time, and it seemed like just a matter of time before MotoGP machinery would do likewise. Strangely, it has taken nearly three decades for a competitive carbon fibre-framed motorcycle to challenge for a race win or a championship.

Honda experimented with an aluminium “shrimpshell” monocoque chassis in its 1978 four-stroke NR500 MotoGP bike, but the other novelties of the technological tour de force (such as the four-cylinder, four-stroke engine which had oval pistons) got all the attention, and the carnivorous British press was merciless in lambasting the machine, despite the fact that it got very close to being competitive against the two-strokes of the day – in hindsight, the technologies and innovative thinking used on the machine were remarkable for their time.

Honda experimented with carbon fibre extensively during this period, and it was used in the fairing of the NR500 in an attempt to reduce weight, though not in any structural sense. Whilst it was considered as a possible material for the NR500’s shrimpshell frame, the shrimpshell concept was abandoned because it significantly reduced access to the machine’s engine for checking, adjustments and part replacement during practice.

There were other racing bikes that employed carbon fibre in varying amounts in their chassis construction during the eighties, most notably the Armstrong Silverstone 250 grand prix racer and New Zealand visionary John Britten used carbon fibre for some structural components on his V1000 which is the only machine we’re aware of to have won at international level sporting a frame made from the wonder composite. See also here for more on the remarkable John Britten.

The first use of carbon fibre as a structural component at MotoGP level was in the 1990 Czech Grand Prix by Italian company Cagiva. The bike was the Cagiva C590 two-stroke 500cc and Cagiva were the first to find out that the stiffness of the carbon fibre frame impacted many other aspects of the machine. Ridden at just two races by Randy Mamola and Ron Haslam, the Cagiva’s frame was quickly replaced with a traditional tubular frame, never to reappear. As John Keogh, the most knowledgeable journalist on the subject of carbon fibre usage in racing motorcycles wrote, Mamola and Haslam found “the suspension set-up and feedback from the carbon frame so fundamentally different that their normal bike adjustments and suspension settings no longer worked and that the bike raised more questions than it answered.”

Carbon fibre became very popular in many aspects of motorcycle construction during the nineties, though the only structural components made of CF were swinging arms and front fork outer, where its torsional strength and light weight offered tangible benefits in reducing unsprung weight. Many other parts of the racing GP machine became CF in the nineties, with brake disks, fairings, tanks and rear sub frames the major beneficiaries.

The critical advantage offered by carbon fibre is no longer that it is simply light and strong but the frame harmonics can be tuned. Ducati have tuned out the harmonics and made the bike considereably easier to ride, according to Stoner.

Throughout the pre-season, Stoner's new carbon Desmosedici Ducati has topped almost every session. At Qatar on the weekend, he topped every session, took pole, and was fastest in both warm-ups. His emphatic flag-to-flag win on the Ducati Desmosedici GP9 suggests Rossi will need to call on all his powers to keep the title.

There's an excellent video on the Motogp.com official site where Stoner’s Crew Chief Cristian Gabarini talks through the ins and outs of the number 27 Desmosedici, explaining how the bike has been modified for Stoner’s unique style and adapted according to the demands and availability of the latest technology. The interview explains the carbon fibre frame and swing arm, credited by Stoner as being a tremendous help in stabilising the bike.

Whilst on that note, if you aren't near a television with a MotoGP telecast, might we suggest you take a look at the direct offerings on the MotoGP site. Many broadcasters that take the MotoGP vision only run the race itself, whereas with the direct MotoGP feed, you get every practice session and a bunch of exclusive video in hi-def. It's just perfect for hardcore motorcycle enthusiasts.

First sighted the day after the Catalunya GP in 2008, the carbon fibre framed GP9 set fastest time in an official test the first day it hit the track. It was a positive debut for the machine in the hands of the then still-reigning World Champion - the Australian set best time of the day with a 1'41.533 on qualifying tyres.

Indeed, there has not been a session since where the GP9 has attended, that it has not been dominant.

In the first preseason test at Sepang in Malaysia, Stoner was best with a 2.01’043, narrowly ahead of Valentino Rossi 's 2.01’137

In the Qatar pre-season session, Stoner delivered a clear message with a time of 1:55.744, nearly a full second better than next-best Jorge Lorenzo with a 1:56.733 and a full 1.2 seconds better than his rival Valentino Rossi on 1:56.972.

At the final Jerez MotoGP official Test, where a new BMW sports car was up for grabs for the fastest, Stoner again blitzed everyone with an incredible lap in tricky conditions. Rain clouds threatened to dampen the atmosphere at the first seriously competitive action of the 2009 MotoGP season, but the Ducati Marlboro Team rider lit up the 45-minute shootout by registering a stunning 1'38.646 lap before the showers came and brought the practice to an abrupt end, smashing the existing circuit lap record by nearly 1.5 seconds. It was an incredibly encouraging result and beyond even Ducatis' lofty expectations, causing him to comment, “I really don't know where that fast lap came from, especially at this track where I've never even been on the podium before! It's been something of a bogey track for myself and the Ducati.”

Having topped all three pre-season tests, two of them comprehensively, Stoner was clearly in awesome form going into Qatar, with perhaps only a question over the strength of his wrist, which was operated on last November, and whether it would hold out over a race distance. His speed was without question though as he topped every session and led from flag to flag. Though at one stage

Ducati is building itself a formidable reputation for innovation and technological excellence. Its desmodromic valve system, traction control and now carbon fibre frame have all been revolutionary in motorcycle design and it is to be applauded for its efforts. The carbon fibre frame of the Ducati is the brain child of Alan Jenkins, who previously worked in Formula 1 for McLaren, Footwork, Stewart and Prost as well as for Penske in Indycar Racing. Jenkins has championed development of the carbon fibre frame which has led Ducati away from its traditional trellis frame for the first time.

Claudio Domenicali, CEO of Ducati Corse, announced the company's commitment to the 2009 season back at the beginning of January, briefly assessing the 2008 season for the Ducati Marlboro Team. “Last season was certainly exciting, with some great moments for us and others that were obviously difficult. When you look at the numbers we won six races, set pole position on nine occasions and set the fastest lap in eight races. If it wasn’t for probably the best Valentino ever, coming back from two difficult seasons and rediscovering the strength to have an exceptional season, those numbers would have surely added up to a successful defence of the world title. When you consider these excellent results and the fact that Casey (Stoner) is still only 23 years old, with plenty of potential to improve even more, once the disappointment is out of the way we can’t be anything but satisfied with 2008 and confident about the season to come.”

He continued: “For 2009 we have many new things, starting with the bike: the GP9 is characterised by a major change in the chassis, with the switch from the traditional Ducati steel trellis chassis with a carbon fibre frame that brings the upper part of the engine up to the level of the steering column. It is a change we have thought about and tested for a long time, firstly with Vittoriano (Guareschi), who is always our first point of reference. He gave his approval to the new system and then the official riders tested it at Barcelona. We won the MotoGP World Championship with the trellis frame so it clearly a very effective design but we have been looking to take another step forward that can help us overcome some of the problems we’ve had, specifically with the MotoGP bike. Amongst the other updates on the GP9 one of the most relevant is an evolution of the engine management system, with a new combination of airbox and mapping that should provide a flatter power curve and improve rideability, as well as improving outright power, which currently remains more or less the same as last year.

Domenicali then discussed the global financial crisis.

“It is definitely a situation we have to face up to right now but I would like to take a slightly different view of it, because whilst it is true that companies are having to face up to changes, with reducing sales of cars or bikes, on the other hand motorcycle racing, like so many other sports, is well loved, it has so many fans all over the world and it will find a way to move forward. We are considering a variety of proposals, together with the other constructors, the organisers and the Federation with this objective in mind; for example modifying the rules on the durability of the engines, which produce one of the biggest costs in MotoGP. The objective of extending engine durability is a matter for 2010 because it involves modifications that include the redesigning of internal components and that takes a certain amount of time. For this season we are looking at taking a step towards it by reducing the length of each practice session. Ducati also has to face up to this difficult situation but we have the support of solid partners: starting with our multi-year agreement with our title sponsor Marlboro, as well as Shell and Telecom. We have also renewed important contracts with Enel and Riello. There are also lots of other companies who promote their products through motorcycle racing with the Ducati Marlboro Team such as Alfa Romeo, Gatorade and Puma. Of course these are tough times but there are still plenty of ways to make sure that the MotoGP World Championship remains a leading promotional vehicle.”

The following statement was issued by Ducati after the race in Qatar:

DESMOSEDICI GP9 MONOCOQUE CARBON FIBRE FRAME

The most significant innovation of the DUCATI DESMOSEDICI GP9 is the monocoque frame in carbon fibre composite.
The technical selection of this type of frame is the next step in the advancement of the bike that has undergone previous major developments in its GP3 and GP7 versions.



The concept of the engine casing has been the guideline of the DESMOSEDICI project. The objective is to create a chassis set-up in which each element carries out a specific function, to obtain the desired rigidity with as little weight as possible, thus attaining maximum efficiency.

The engine, the main frame, the rear sub-frame, the rear suspension system (comprising swing-arm and linkage) and the front suspension system are the main components of the bike.
 
 The basic idea is to abandon the classic concept of the chassis as the element that connects all other elements, in favour of a design in which the engine is the central element to which the main frame, rear sub-frame and rear suspension system are individually connected.
 
 The GP3 was unique in having a rear swing-arm that was attached solely to the engine. In particular both the swing-arm pivot and the suspension linkages were connected directly to the engine without any attachment to the main frame. 

The GP7 featured a main frame that was totally detached from the rear sub-frame. Basically the engine was the central element of the bike. The main frame was used as link between the engine and the steering head. The rear sub-frame linked the engine to the seat and to the footpegs and controls. The two frames, main and rear sub-frame, that were still linked to each other on the GP3, were now only attached to the engine on the GP7, meaning that they were smaller and lighter.
 
 On the GP9 the main frame is formed to connect the engine to the steering head. The main frame now also incorporates the air-box in one single construction. This monocoque construction allows the air-box to function efficiently within the main frame.



Choosing to utilise the carbon fibre composite technology to create the frame means that, on the one hand, one can mould the piece into the desired form without incurring enormous equipment costs and, on the other hand, varying levels of rigidity and torsional characteristics can be attained simply by altering the type, the number and the directional orientation of the carbon fibres, using the same equipment.
 
 In testing carried out up until now the GP9 guarantees greater precision and stability in breaking and on entering corners. We maintain, however, that only by using it to race on the various world circuits will we be able to properly evaluate the potential of this technical solution. Employing the said technical solution in competition at the maximum level is the only way to effectively assess it in all its aspects.


DUCATI DESMOSEDICI GP9 Technical Specifications

Engine: liquid-cooled, 90 degree V4 four-stroke, desmodromic DOHC, four valves per cylinder. Capacity: 799cc Maximum power: more than 200hp Maximum speed: speed quoted by Ducati is "in excess of 310 kph/192 mph" - Stoner was timed at 331.1 km/h down the chute at Qatar during the race tonight. Transmission: Six-speed cassette-type gearbox, with alternative gear ratios available. Dry multiplate slipper clutch. Chain final drive. Carburation: Indirect Magneti Marelli electronic injection, four throttle bodies with injectors above butterfly valves. Throttles operated by EVO TCF (Throttle Control & Feedback) system. Fuel: Shell Racing V-Power Lubricant: Shell Advance Ultra 4 Ignition: Magneti Marelli Exhaust: Termignoni Frame: Carbon fibre chassis, pressed aluminium swing-arm. Suspension: Öhlins upside-down 42mm front forks and Öhlins rear shock absorber, adjustable for preload, compression and rebound damping. Tyres: Bridgestone 16.5" front and rear Brakes: Brembo, two 320mm carbon front discs with four-piston callipers. Single stainless steel rear disc with two-piston callipers. Dry weight: 148kg

About the Author
Mike Hanlon After Editing or Managing over 50 print publications primarily in the role of a Magazine Doctor, Mike embraced the internet full-time in 1995 and became a "start-up all-rounder" – quite a few start-ups later, he founded Gizmag in 2002. Now he can write again.   All articles by Mike Hanlon
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