Finite bodies supporting two-dimensional under surface flows behind “contained” plane shock waves of the type discussed by Professor Nonweiler in a recent paper are currently receiving attention from both theoretical and experimental workers. The experimental work already undertaken by the RAE has given hopeful indications that such bodies, characterised by a re-entrant lower surface in cross section, compete closely with more familiar convex bodies in terms of lift/drag ratio, and furthermore preserve the two-dimensional character of the flow away from the design incidence.

The purpose of this note is to point out that:

(a) Delta wings with inverted V or W cross sections are geometrically simple examples of a more general family of possible shapes supporting two-dimensional flow behind a plane shock.

(b) The concept may be extended to bodies supporting two-dimensional flows with multiple shocks (leading to isentropic compression in the limit) or shock-expansion systems.