Les tests à haute vitesse du véhicule le plus rapide sur terre ont commencé.

Ça faisait longtemps que l'on n'avait pas parlé de Bloodhound. En réalité, ça fait même déjà presque un an depuis qu'on a appris que la machine la plus rapide sur terre renaissait de ses cendres, et avait été rebaptisée Bloodhound LSR. Depuis, la véhicule à réaction s'est offert une nouvelle peinture, de nouveaux réglages, et l'équipe en charge du projet est actuellement en Afrique du Sud pour conduire des tests de vitesse. Le but ultime ? Atteindre les 1000 mph, soit 1609,34 km/h, soyons précis. Mais pour l'heure, les vitesses atteintes sont plus sages. Si on peut dire que rouler à 334 mph, soit 537 km/h, est "sage". 

C'est dans le désert du Kalahari, sur le lac salé de Hakskeenpan, là où l'ancienne Bloodhound s'était déjà entrainée, que la LSR mène ses essais. Les tests de vitesse doivent se dérouler en plusieurs étapes conçues pour tout tester, de l'équipement embarqué à la manière dont le châssis réagit dans diverses conditions et vitesses. S'assurer du bon fonctionnement du moteur est évidemment une partie extrêmement importante de ce processus, car la turbine Rolls-Royce EJ200 est empruntée à l'avion de chasse Eurofighter Typhoon, de 135'000 ch. Rien que ça. 

Galerie: Bloodhound LSR tests de vitesse

Durant ce galop d'essai, la LSR de Bloodhound a accéléré d'environ 50 mph à 334 mph (80 à 527 km/h) en moins de 20 secondes. Après quoi on a coupé le moteur et calculé la résistance au roulement du véhicule. La course s'est également déroulée avec de forts vents de travers, ce qui a permis de déterminer les limites à ne pas franchir pour les futures runs à grandes vitesses et tentatives de records.  

"Nous avons fait deux tentatives très réussies aujourd'hui, la deuxième atteignant une vitesse maximale de 334 mph - passant de 50 mph à 300 mph en 13 secondes" a déclaré Andy Green, pilote de ce Bloodhound LSR et détenteur du record actuel de vitesse sur terre. "Il y avait un fort vent de travers soufflant en rafales à plus de 15 mph (24 km/h) et nous avons établi que c'est à peu près la limite pour courir dans la voiture. Nous sommes heureux parce que c'était un test concluant, maintenant nous sommes prêts à passer à des vitesses plus élevées."

Cette série marque le début des essais à grande vitesse qui mèneront finalement à une tentative de nouveau record du monde. Le record actuel à battre est de 763,035 mph (1227,98 km/h) établie par Green en 1997. Si le record est battu, l'équipe de la Bloodhound LSR visera alors les 1000 mph. Des tentatives qui devraient avoir lieu l'année prochaine.

Source: Bloodhound LSR
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Bloodhound LSR achieves its fastest ever speed as testing programme heats up


• Bloodhound hits an all-time fastest speed of 334 mph as test programme begins in
earnest
• Bloodhound car’s full reheat engaged for 12 seconds
• 50 – 300 mph reached in 13 seconds
• Crucial data on cross wind speed limits gathered
• Team pull together to overcome initial teething problems


The Bloodhound LSR team today passed a major milestone, as the car hit 334 mph (537 km/h)
on the Hakskeenpan desert racetrack: the highest speed it has ever achieved.


Three ‘run profiles’ have now been completed, starting at 100 mph, building to 200 mph – the
previous top speed achieved at Newquay in 2017 – before hitting 334 mph in Run Profile 3.
The car’s EJ200 jet engine ran with full reheat (a.k.a. afterburner) for 12 seconds,
demonstrating it is in full working order, plus providing impressive drama for those watching.


Run Profile 3 marked the true beginning of the high speed test programme, as all systems
necessary for running with reheat have now been tested and checked. The car’s speed will
be built up in 50 mph increments over subsequent run profiles, carried out over the next four
weeks, with a target top speed above 500 mph for this testing programme.


Bloodhound driver and current World Land Speed Record holder Andy Green said: “We’ve
had two very successful runs today, with the second run reaching a max speed of 334 mph –
going from 50 mph to 300 mph in 13 seconds. There was strong cross wind gusting at over
15 mph and we’ve established that this is pretty much the limit for running in the car. We’re
happy because this was a successful test, now we’re ready to progress on to higher speeds.”

 

Run Profile 1 – a static engine test, followed by a very slow speed (max 100 mph) check of
the steering and brakes.
Run Profile 2 – 200 mph achieved using max dry power (power without extra fuel for reheat)
on the jet engine, then a coast-down to establish rolling resistance.
Run Profile 3 – 350 mph achieved using full reheat, with stability tests before and after peak
speed, then a coast-down period after engine shutdown to measure rolling resistance
without idle thrust from the jet engine. Parachute data collected.


Teething problems overcome by perseverance and teamwork
Despite Monday’s momentous achievement, the first week of high speed testing has not been
plain sailing. The Bloodhound team have faced a number of challenges since arriving with the
car in the Northern Cape of South Africa on Monday 21st October.


The Eurofighter Typhoon EJ200 jet engine powering Bloodhound LSR car is the same one
used during the low speed tests at Cornwall Airport Newquay in October 2017.
Since then it has been in storage with Rolls-Royce, the engine’s manufacturer, where it was
filled with a corrosion inhibitor fluid, used to keep the engine in perfect condition. This waxy
fluid is blown into all the oilways to prevent degrading when not in use.


The re-commissioning of a jet after such a long time in storage involves starting the engine to
burn off the corrosion inhibitor so it’s normal for it to take two or three attempts to start.
However, after two unsuccessful engine start attempts, the system engineers became
suspicious at the lack of smell of fuel. Checking again, it appeared that the Bloodhound system
had an issue with a fuel sensor calibration which was stopping a pump sending fuel to
the engine.


After recalibrating the sensor, the team made a few more attempts. This time the fuel pump
worked perfectly, and the jet received fuel and ignited, burning off the corrosion inhibitor fluid.
The problems were not over, however. The start-up cycle took four seconds longer than the
permitted 60 second start process allowed by the DECU (Digital Engine Control Unit). If the
turbine hasn’t reached idle speed within this time, it is automatically shut down as a
safety precaution.


The next time out in the heat and altitude of the desert testing ground, which is 600 m above
sea level, proved too much for the Air Start Cart. This is a piece of ground support equipment
with a small jet engine which is plugged into the car and acts as a starter motor for the
main engine.


To help it engage, the team turned the Bloodhound car into the wind, which helped add a few
percentage points of power through the jet engine. A head wind helped spin the jet’s turbine,
and this time the jet started perfectly and sustained power for the required amount of time to
allow the ‘fill to spill’ oil checks to be carried out. After shutting down, while the car was towed
back into the tech centre, a water leak was spotted. This proved to be a split in some welding
on a coolant tank, caused by another pump issue.


Bloodhound LSR CEO Ian Warhurst said: “I’ve been impressed with the tenacity of the team
to work through a challenging first week of testing in the Kalahari Desert. With all those issues
resolved it’s exciting to be moving into the high speed phase of the testing and get a max
reheat run under our belts. Witnessing Bloodhound blasting from 50 mph to 300 mph in
13 seconds and on to 334 mph was jaw dropping. British engineering at its finest.”


Desert racetrack holding up under the strain
The first few runs on the desert have proved the surface is consistently firm, albeit with a slight
soft crust in some areas. This flakes away to leave a solid surface to run the car. The V-shaped
wheel profiles leave a shallow 50 mm wide groove in the desert surface.
The racetrack was prepared by a 317 strong workforce from the local community, funded by
the Northern Cape Provincial Government, under the watchful eye of track boss Rudi Riek.