The Chassis for Aussie Invader 5R is unique, a typical Australian approach to a complex problem. How do you build a 52′ long (16 metres) rocket car with a limited budget and all the following prerequisites?
- Maximum safety
- Minimum chassis flex
- Be simple in construction
- Extremely strong
- Easy to construct and work on
The answer is simple, use a 40 foot (12m) long high grade steel pipe with a 36 inch (914mm) outside diameter. This pipe is 10mm thick and was rolled from a flat sheet and seam welded. The pipe actually weighs a massive 2.5 tonnes and this weight also serves another purpose and it is not what you might think (covered later in this section).
Sometimes man does not always have the answers to complex problems and looking to nature can often supply the answer. Some of the toughest and strongest creatures on the planet are insects and Aussie Invader has borrowed its construction from their example, having it’s skeleton (chassis/mainframe) on the outside, unlike most race cars that have theirs on the inside, covered with a thin protective skin.
This reversal gives Aussie Invader 5R a very strong and rigid structure that protects all the rocket pressure vessels, fuel and oxidiser tanks as well as the driver.
This design also keeps the weight up and that helps slow the car’s acceleration down. It may seem strange to try and build the fastest car in the world and then intentionally try and slow it down, but that is what we have done.
The 40′ mainframe weighs in at 2.5 tonnes and this weight will help slow the acceleration down, as we need to limit the car to a maximum acceleration of 3.2 g’s. If we exceed this the wheels will not be able to spin up quickly enough and they will lose traction, meaning all four wheels could spin at different speeds and want to pull the car in different directions, making handling almost impossible.
A “V” shaped underbelly runs the length of the car; this is to deflect the ground generated shock waves and a “top hat” section runs aft of the drivers seating position which is approximately in the middle of the car. The “top hat” also houses the pumps and regulators for the cars hydraulics as well as the air brake mechanics and doors, on-board computers and the two chute cans at the rear. This structure is also used to add support and position the vertical and horizontal stabilisers.
A series of bulkheads along the length of the mainframe separating pressure vessels, oxidiser and fuel tanks from the driver and adds further stiffness and strength. A 1.5″ x .083″ rollcage made from 4130 steel is welded to the forward and aft driver bulkheads. These not only protect the driver in the event of an accident but aids in stiffening the “cut-out” for the driver’s cockpit. A detachable composite nose, bolts to the front of our mainframe and houses our on-board batteries and data monitoring computers. Rosco and the Aussie Invader team believe that this unique and simple car design will help them break the Land Speed Record and move on to 1,000 mph.