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Maximum Impulse
Posted by : Ray Wakefield - Date: 9 Oct 2003 at 13:35

The period leading up the record attempt is split into a number of phases, each with its own clearly defined tasks and targets.

Richard Brown’s first bike, the Boost Palouste, unveiled in 1994 was a jet/rocket motorcycle.

In September 1999, Richard and his team travelled to the famous Bonneville Salt Flats in Utah to make an attempt on the World Record Even though he only made a total of seven runs, the last two runs were made at speeds in excess of the existing record, but due to technical difficulties meant that the required return run could not be made on either occasion. The seventh and fastest run was made at a speed of 330.639mph for the mile and 332.877mph. Unfortunately the team’s time on the salt ran out before further runs could be made.

Maximum Impulse is two wheeled rocket propelled land bound ‘missile’ capable of re-writing the motorcycle speed record books.

With a design peak speed of over 500mph; Richard’s latest machine owes more to the work of aerodynamicists and to the space-race than the British motorcycle industry. Material and engineering supplies from across Britain have supported the construction of the vehicle as a showcase for their high technology and performance products.

Following an intense design period with co-designer Andy Scott, the build jig was put in place and the first metal cut in October 1996 as Richard started to create his 26foot (8m) long vehicle and in 1999 having travelled to the USA Richard achieved a mile average speed of 531.998 kph (330.639 mph) and a kilometre average speed of 535.599 kph (332.877 mph).

A cut away view of Maximum Impulse, the 500 kph rocket powered bike

To qualify as a motorcycle it has of course only two wheels – one that is steerable by the rider. The wheels do not carry tyres because, for the speeds that will be achieved, rubber pneumatic tyres are not available. Spinning at over 9000 rpm, the wheels have special solid profiled ‘rims’ formed on to them. Suspension for each wheel will help provide a smooth ride for Richard. The beach sand or desert playa course provides a degree of cushioning, as well as the ‘grip’ for steering changes.

The rider lies back in a reclined position, strapped in to and surrounded by a safety ‘capsule’, formed within the cockpit with a solid roll-over cage above his head and body. A front bulkhead protects the rider from the rocket propellant tank, which is mounted in to the fully triangulated spaceframe chassis. Behind the rear cockpit bulkhead are mounted various control valves and regulators. These are actuated by the rider to send the oxidant to the catalyst packs and combustion chambers of each rocket.

Aft of the rear wheel are the three hybrid rockets combining an HTP liquid mono propellant element with a solid propellant to produce high energy intense combustion stacked one above the other which when fired in sequence will push Maximum Impluse to the record speed.

Slowing down at the end of a run is by drag parachute released by the rider after the shutdown sequence and a purge of the rocket engines has taken place. Once the vehicle has slowed, a rear wheel brake is used to slow the bike to complete halt.

As riders of any bicycle know, once at rest you need to put your feet down to maintain the bike upright. In a vehicle of this type this cannot be done so retractable stabilisers which will keep the bike in the upright position after each run are used.

Aerodynamics and the need to limit frontal area have dictated the shape of Maximum Impulse. Dave Watson, the team’s aerodynamics specialist has worked in Formula 1 and currently works on high speed Champ Cars in the USA . The final body shape was perfected in the full size wind tunnel of MIRA-the Motor Industry Research Association, and has been the subject of a high technology Computational Fluid Dynamics (CFD) study. The body is constructed from hand shaped aluminium with a moulded carbon fibre tail section.