The Richard Nowland led group chasing the World Land Speed record has unveiled a new aerodynamic design and propulsion system for Jetblack.
Two hybrid rocket motors will now drive Jetblack, dispensing with the combined jet engine and rocket propulsion system in the earlier design. The rocket motors are expected to give the New Zealand challenger more than 70 percent extra thrust in its bid to breach the 1000mph (1610kmph) mark.
“The work the group’s design team has undertaken over the past 12 months has resulted in a car that is less complex, produces considerably less drag, has greater controllability and the potential to achieve the target speed more quickly. In all, this is a significant advance over its predecessor,” says Jetblack’s managing director and founder Richard Nowland.
The move to rocket propulsion alone has been under development since last year with the Space Propulsion Group (SPG) in the US, a world-leader in hybrid rocket propulsion. It was selected due to its inherent safety and simplicity over other rocket systems.
“Space Propulsions advanced hybrid rockets deliver very high performance while retaining the safety, simplicity and controllability of classical hybrids. The inherent safety, throttling and shut down are the key virtues of SPG’s rocket technology which makes it ideal for this particular application,” says the Group’s co-founder, president and chief technical officer Dr Arif Karabeyoglu.
The change from jet and rockets to rockets only was made after discussions with SPG on the controllability of the rocket motors. SPG are developing a hybrid rocket propulsion system that can be throttle controlled, which means the thrust of the rocket can be varied.
This work-in-progress will represent a significant breakthrough and will provide Jetblack with a competitive advantage, says Mr Nowland.
“The new design represents a significant advance for the design of the vehicle and with this last major decision now behind us, the team is focused on the integration of the other componentry required, preparatory to building the challenger vehicle in 2013.”
The hybrid rockets in the new design produce thrust of 35,000lb x2 as opposed to 20,000lbs x2 in the older, and are of the same type that have been chosen to power Virgin Galactic’s passenger spacecraft.
Unlike jet engines which require an air intake, all the fuel and oxidiser with the rocket propulsion system can be carried on board the vehicle, with positive effects on both the aerodynamics and the vehicle’s structure.
“The new challenger’s design minimises drag. It produces approximately onethird less drag than the earlier versions, enabling the car to accelerate to the required speed faster. The new design is also shorter by almost three metres so it has less surface area, which has contributed to its lower aerodynamic resistance, and weighs around two tonnes less,” says Richard Roake, Jetblack’s lead aerodynamicist.
“A further benefit of having a solely rocket powdered design is that we have been able to lose the complexity of having control systems for each engine type,” says Mr Nowland.
“We now have far simpler and safer vehicle using Nytrox, which is the oxidiser for the rocket motors. Nytrox is a proprietary formulation from SPG and contributes appreciably to the high performance of the rocket motors – the system is pressure fed and requires no pumps.”
During a high speed run, the new Jetblack will shed around 3,100kg of weight, around 40 percent of the total weight of the car.
The Jetblack team plan to select the venue for testing and the subsequent high speed runs within 12 months and begin to build their vehicle in 2013. Initial low speed testing will take place in 2014, with the high speed testing and challenge taking place during 2015 and 2016, by which time it may be facing a tougher challenge as Bloodhound is looking to mount its 1000mph challenge towards the end of 2013 in South Africa.
The current Land Speed record stands at 763mph set by Thrust SSC in October 1997 at Black Rock Desert in Nevada.
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