This note attempts to clarify some basic ideas, and correct some common misunderstandings, on wing flexure-torsion flutter. Topics include:

• (i) an understanding of the physics of wing flexure-torsion flutter through a number of specific examples,

• (ii) an examination of the energy interpretation of the physics of flutter, indicating its limited usefulness,

• (iii) a discussion of the significant differences between wing flexure-torsion flutter and the Duncan flutter engine,

• (iv) a graphical representation to assess the contribution of various parameter to flutter onset,

• (v) subcritical response below the critical flutter speed,

• (vi) some practical wing flutter considerations.

After I had described the flight theory and practical ornithopter of Carl Friedrich Meerwein, my attention was drawn to a relevant passage in Joachim Heinrich Campe’s Sammlung interessanter und durchgängig zweckmässig abgefasster Reisebeschreibungen für die Jugend. Translator of Robinson Crusoe, traveller, and populariser of high culture, Campe included in his improving collection of travel decriptions an account of a journey from Hamburg to Switzerland which he himself had undertaken in 1785. Having reached Giessen on his way south, he was about to press on to Frankfurt when some acquaintances urged him to stay a day or two longer to watch something curious: Carl Meerwein was about to attempt to fly.

This paper presents experimental data highlighting the effects of a forward facing aerodynamic spike on the pitch stability of a blunted cone in hypersonic flow. Spike length and angle of attack variations on stability derivatives are described. Suitable application of the inviscid embedded Newtonian pitch stability prediction technique shows how the influence of spike aerodynamics may be successfully modelled. The paper extends the knowledge of aerodynamic spike flow effects, which have to date concentrated on aerodynamic drag reduction qualities at zero degrees angle of attack.

The experimentally observed changes in the location of boundary layer separation on the cylindrical afterbody of a tangent-ogive-cylinder, placed at incidence in a uniform flow, are related to the phenomenon of laminar-turbulent transition. Existing knowledge of the transition mechanisms which operate in general, three-dimensional; boundary layers, is described and simple prediction criteria are derived for this configuration. These criteria are compared with the currently available empirical methods for the prediction of critical Reynolds numbers for such flows. It is demonstrated that the methods which have been published to date are incomplete and the accompanying analyses are based upon superficial and erroneous physical arguments. The implications of boundary layer transition on the normal forces generated by a cylindrical afterbody are also discussed. Finally, the possibility of using transition fixing to establish ‘high Reynolds number’ separated flows in ‘low Reynolds number’ wind-tunnel facilities is briefly considered.