The first decision was to decide exactly how to build the model of Bluebird CN7.  My existing 1:5 scale model of Donald Campbell’s Bluebird K7 boat is constructed of a moulded fibreglass shell, so my initial thoughts were to construct CN7 using the same construction technique. 

Image below: My Bluebird K7 model at the Ruskin Museum model boat regatta, along with Gina Campbell, daughter of Donald.

After carefully considering build options I decided that I would like to build my model of CN7 to the same scale as my model of K7 and ideally using same construction technique as that of the full size car.  It would be a 1:5 scale model constructed with aluminium chassis and skinned in aluminium.

At 1:5 scale this would make the model would be 183cm long, 49cm wide and height of 29cm, which is quite a large model but still a size that could be transported in the back of an estate car.  Although weight could be a problem, but hopefully with careful design the weight could be minimised where necessary.

Next decision was power plant, again my intention was to stick as close as possible to the full size car, so my current intention is to power the model with gas turbine powering the wheels.

Items that need to be considered:

Chassis: Chassis will be constructed as per the full size car with full length beams and cross members for rigidity.  Thanks to my sponsors Bespoke Composite Panels (BCP) for assisting with manufacturing the main beams from aluminium honeycomb panels, which are almost identical to that which was used in building the full size CN7.

Image below: Construction of the chassis for Bluebird CN7 at Motor Panels (Coventry) Ltd in 1960.

Engine:  There are a number of turboprop gas turbine engines which are made for fitting to RC model aircraft.  These could be adapted to drive the wheels through front or rear (or both).

Image below: Bristol Siddeley Proteus engine under test for Bluebird CN7.  This engine was originally fitted to the prop. powered Fairey Gannet anti-submarine aircraft.

Transfer Gearbox: Most likely this will be custom made.

Final Drive Gearboxes: I am still deciding whether to make these or to buy complete gearboxes, which are available commercially.

Tyres: The tyres are 264mm diameter (10.4″) x 33mm (1.25″).  Options for these are, obtain a commercially available tyre, although suitable tyres are proving very difficult to source.  Alternatively 3D print the tyres with a flexible Thermoplastic Polyurethane (TPU).  3D printing is looking favourite.

Bodywork: The bodywork will be sheet aluminium, the most challenging part of this will be the wheel arches as these are a tight profile and each one is different and this will require four different formers to be made.

Wheels: The wheels will be approx. 226mm diameter (8.9″).  The intention is to machine these from single billet of aluminium.

Images below: 3D CAD drawing of wheel design and a test 3D print, printed in PLA filament.