Landing gear structure is developed predominantly using safe life design criteria. Health monitoring and structural prognosis techniques for landing gear cannot focus on crack detection; techniques for determining input loads and calculating damage or methods for directly measuring material damage must be employed. This paper will discuss Messier-Dowty’s research into structural monitoring over the past several years. Principally, direct damage detection systems and load monitoring systems will be discussed.

Trailing edge blowing over a Coanda surface has been utilised as a circulation control mechanism for increasing the lift of an aircraft wing. Typically, high energy air is blown from a narrow spanwise slot over the rounded trailing edge of a wing and the air supply is modulated to effect a degree of lift control on the wing. This configuration produces an aerodynamic force in a uni-directional sense only. An alternative novel flow control actuator is described which utilises a simple variable geometry Coanda surface with upper and lower spanwise blowing slots to achieve fully proportional bi-directional control in the manner of a conventional flap. A prototype device has been wind-tunnel tested and is shown to have substantially linear response characteristics and to be as efficient as an equivalent flap surface. The performance of a flow control actuator suitable for small UAV applications is described.

This 2007 Lanchester Lecture covered a theoretical result, thought to be new and in print in the Journal of Fluid Mechanics, and some lines of thought on the interpretation of induced drag and recurring paradoxes which interfere with teaching ‘how wings work’. Some of these were presented in the author's 1998 Annual Review. The difficulties are not confined to drag, but also concern lift; they are no less severe in two dimensions than in three. The flow-field in the far wake of an aircraft is examined with the primary purpose of identifying lift and drag in a simple and unified manner, preferably an intuitive one acceptable by novices (and even by those who mind using Bernoulli's equation!).

This paper describes a method by which, without the use of external personnel or equipment, take-off and landing distances of an aeroplane may be estimated. An error analysis for the method, allowing determination of outcome accuracy, is also shown. The method is validated through use of flight test results from two certification programmes: one on a light aeroplane, and one on a microlight aeroplane.

Experiments have been conducted to assess the effects that sub-boundary-layer vortex generators (SBVGs) have on reducing normal shock-induced turbulent boundary-layer separation. The freestream Mach number and Reynolds number were M = 1·45 and 15·9 × 106/m, respectively. Detailed measurements of a fully developed, flat plate turbulent boundary layer were used in order to assess the performance of ten different SBVG configurations. The SBVG performance was assessed by comparing total pressure profiles measured upstream of separation and downstream of reattachment. Static pressure distributions, near surface total pressure distributions, oil flow visualisation and Schlieren photographs were also used. The effect of SBVG height was investigated. The results show the largest SBVGs with height, h = 55%δ, provided the greatest static pressure recovery and maximum mixing. However, the shock pressure rise (wave drag) was highest for this case.

An experimental investigation of aerodynamic drag reduction by counter How plasma jet injection from the stagnation region of a hemispherical blunt cylinder model flying at hypersonic Mach numbers are presented. Experiments are carried out in a hypersonic shock tunnel at four different jet-to-pitot pressure ratios namely 15·3, 24·52, 72·5 and 96·67 and three supply powers, namely 1·8KW, 2·7KW and 3·6KW. The flow fields around the test model are visualised using high speed schlieren technique. Direct force measurement is also performed using a single component accelerometer balance. The weakly ionised argon plasma jet has an electron temperature around 6,400K and electron number density ∼1.64 × 1015cm3. With plasma jet at pressure ratio 72·5 and 1·8K.W supply power the reduction in drag is found to be ∼28% (more than its cold jet counter part) although the plasma jet momentum is less than its cold jet counter part.

One hundred years on from the advent of aeronautics at Queen Mary, University of London, developments in lighter than air technology have progressed at a somewhat slower pace than the technology for heavier than air. Innovations afforded by the ‘discovery’ of helium, the development of the modern day hot air balloon and the application of new materials have all contributed to today’s technical innovations. A review is given of the past history of lighter than air, a note is made of the current state of the art and a brief overview of future applications is discussed. The author’s personal experience in long distance gas balloon flights is mentioned.