E3 tether car

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David Giles produced a very detailed article on the design and development of a modern tether car. This new article from David outlines the construction of his latest superbly engineered car.

"DJR 3" (Class E3 tether car)

The latest 3,5cc car built by David Giles for the 2006 competition season

The car has been designed to provide the minimum cross–sectional and projected area whilst covering all the relevant components, hence the ‘camel with broken back’ appearance!

The car soon after completion at the end of May 2006. The upper body is a CFRP moulding using 2 layers of 0,25mm thick carbon cloth and ‘West System’ epoxy resin cured at room temperature. The lower pan is machined from a billet of 19mm thick E30 Al alloy plate. Note that front axle fairings have yet to be fitted. It first took to the track at the European Championships in Poland, where it immediately earned the nickname of ‘old elephant ears’ due to the front suspension arrangement!

Side elevation showing how pan profile follows the shape of the components to give minimum projected area. Front axle fairings are from litho plate filled with epoxy resin & micro balloons. They have an inverted aerofoil section and do not rotate with the front axle. Suspension damper is a ‘Kyosho’ VZ075 unit.

View showing tuned length pipe, fuel tank & shutoff and on-board battery arrangement. Pipe is stainless steel, CNC machined by Eduard Stelling in Lithuania. Exhaust outlet and stinger bends are home constructed from brass. Feed problems have limited the performance to date; a new tank will be part of the preparation for the 2007 season. Engine is built around a ‘JP Racing’ FX21 crankcase (a "badge engineered" NovaRossi) using a mix of Nova and JP parts with modified porting and my own venturi & fuel feed system.

These 2 views, from above and below, clearly show the amount of ‘sculpting’ to achieve a minimum sized car that complies with the rather prescriptive rules for this class.

Thanks to David for producing this material for OTW.