News

Computer-Aided Design (CAD) of the Stirling front fuselage and cockpit section

Following the end of the Second World War, Stirling aircraft were scrapped without thought of preserving an example for posterity so sadly there are no surviving Stirling aircraft or even a cockpit section on display to the public. The Stirling Project is planning to address this by building a complete and fitted out, front fuselage section of a Stirling bomber. This will be full scale, and of aluminium riveted construction, as close to the original as possible and will include the cockpit coupe/canopy, the correct frame stations, longerons and skinning, as in the original manufacture.

There are few surviving original Shorts manufacturer’s drawings for the airframe, however following over 30 years of research, we have gathered a vast amount of information with which to build this section for display to the public. During this time we have been actively working to recreate the necessary foundation steps and using original Stirling parts, wreckage, some original drawings, original data and photographs we are now also using modern technology to produce a three dimensional CAD (computer aided design) ‘model’. 

This will help us to ‘reverse engineer’ a complete front fuselage section. The finished section will encompass the whole flight deck with our pilot’s instrument panel, throttle box, pilot’s seats & chassis, rudder pedals and control columns, all of which are simultaneously being worked on by members of The Stirling Project.

We also intend to install our previously completed FN5 front gun turret. The Cockpit section will eventually include the wireless operator and flight engineer stations as well as the pilots, bomb aimer and navigator station. This would make it 24 feet in length! It’s not just the funding that we require, however, it will also depend on working space, having sufficient skilled and unskilled volunteers, tools, equipment and of course materials and resources. 

This is a big undertaking and will depend on raising further money. It will need to be planned carefully but with your help this can be achieved. If you would like make a donation, be involved, or can offer any Stirling parts or equipment, we would be most pleased to hear from you.

CAD view side

This computer screen view shows the current state of development of the 3D CAD model. Many hours of work have been spent getting this far but there is still a lot to do. The exact shape of the front taper towards the gun turret is now defined. Photographs of some of the parts used to gather data are shown in position for reference.

Cockpit

View Wartime side view photo of a Stirling front fuselage for comparison

CAD top view

Computer screen view of the 3D CAD model from above. The pilot’s escape hatch is shown and will be fitted to our fuselage.

CAD frontal view

Computer screen view of the 3D CAD model from the front.

CAD Isometric view

Computer screen view of the 3D CAD model, projected from a point forward of the nose and to starboard

Top Escape Hatch

This is an original Stirling pilot’s escape hatch and will be fitted to our fuselage coupe

Windscreen Coupe Corner

This salvaged piece was vital to us in defining the front edges of the windscreen and the coupe.

Fuselage-Frame 3

This is a Shorts factory photo showing the front fuselage section at the natural fuselage break point at the 3rd frame, behind the front gun turret. The accompanying photo shows a piece of the framework of the bomb aimer’s window, which was very useful to us in defining the curve around the window.

 

Front Hatch

Pieces salvaged from Stirling LJ628 which crashed in the Peak District in 1944. They gave us important information about the floor around the front escape hatch, under the bomb aimer’s station.

Bomb-Aimer’s Window Frame

This is another item which was recovered from a Stirling crash site. Yet another piece to help us complete the great Stirling “jigsaw

Computer-Aided Manufacture of Stirling Cockpit Components

The Stirling pilot’s seat chassis is quite a complicated assembly, fabricated from several components, amongst which are the so-called “fish plates” that stiffen the junction between the seat-back and the base.

To manufacture these fish plates, we used the latest techniques, including computer-aided design and manufacture/machining (CAD/CAM). This screen shot shows the computer simulation of the machining from our CAD/CAM-generated tool path.

Once drawn up in CAD from an original paper Shorts drawing, the cutting tool path is generated by a CAM program. This is the information required by a CNC (Computer Numerical Control) milling machine to cut out the L shape to the exact size and centre drill all the rivet holes.

There were eight of these to make and this technique saved us hours of work and also produced accurate parts. This is just an example of parts that already have been, or will be produced by these methods. This is one way in which we can ‘Speed up on Stirlings’!

Fish plate machined via computer modelling

One of the CNC machined fish plates, shown still on the CNC milling machine, straight after machining. This has been cut out of a sheet of aluminium and shows the cutter path and the rivet holes which have been centre drilled.

Chassis rails for pilot’s seat

This shows one of the pair of side rails incorporated in the chassis of a pilot’s seat. Like the fish plate above, this rail has been machined by CNC and is shown secured temporarily to it by special skin-pin clamps. These hold the two components in correct alignment while they are being permanently fastened together with rivets