Monocoque

[3] Other semi-monocoques, not to be confused with true monocoques, include vehicle unibodies, which tend to be composites, and inflatable shells or balloon tanks, both of which are pressure stabilised.

Early aircraft were constructed using frames, typically of wood or steel tubing, which could then be covered (or skinned) with fabric[4] such as Irish linen or cotton.

By considering the structure as a whole and not just the sum of its parts, monocoque construction integrated the skin and frame into a single load-bearing shell with significant improvements to strength and weight.

One of the earliest examples was the Deperdussin Monocoque racer in 1912, which used a laminated fuselage made up of three layers of glued poplar veneer, which provided both the external skin and the main load-bearing structure.

[6] This style of construction was further developed in Germany by LFG Roland using the patented Wickelrumpf (wrapped hull) form later licensed by them to Pfalz Flugzeugwerke who used it on several fighter aircraft.

[8][9] In parallel to Dornier, Zeppelin also employed Adolf Rohrbach, who built the Zeppelin-Staaken E-4/20, which when it flew in 1920[10] became the first multi-engined monocoque airliner, before being destroyed under orders of the Inter-Allied Commission.

Despite advantages, aluminium alloy monocoques would not become common until the mid 1930s as a result of a number of factors, including design conservatism and production setup costs.

Strictly considered, it was more of a semi-monocoque, as it used a box-section, pressed-steel frame with twin side rails riveted together via crossmembers, along with floor pans and rear and front bulkheads.

[19] The F750 event at the 1973 Isle of Man TT races was won by Peter Williams on the monocoque-framed John Player Special that he helped to design based on Norton Commando.

[22] The bike had other innovative features, including an engine with oval shaped cylinders, and eventually succumbed to the problems associated with attempting to develop too many new technologies at once.

[28] The Atlas was very light since a major portion of its structural support was provided by its single-wall steel balloon fuel tanks, which hold their shape while under acceleration by internal pressure.

A balloon tank skin only handles tensile forces while compression is resisted by internal liquid pressure in a way similar to semi-monocoques braced by a solid frame.

Blue Origin's upcoming New Glenn launch vehicle will use monocoque construction on its second stage despite the mass penalty in order to reduce the cost of production.