An improved method for producing foam-filled fibreglass-reinforced plastic propeller blades

An improved technique for producing foam-filled fibreglass propeller blades suitable for use on powered wind tunnel models is described in detail. If large numbers of blades are required this method can considerably reduce cost and time needed for manufacture.

Freeflight measurements of the zero-lift drag of a slender ogee wing at transonic and supersonic speeds

The zero-lift drag of a slender-wing model has been measured using the free-flight technique and the wing wave drag has been deduced by subtracting the non-wave-drag components. The results are presented without correction for the drag increment caused by the transition strip and show a smooth variation of the wave drag factor Ko with Mach...

Free-flight tests of vortex generator configurations at transonic speeds

Tests have been made to investigate the effectiveness of vortex generators in alleviating the adverse effects of shock-induced boundarylaer separation. The variation in effectiveness of a flap control on an unswept wing in the transonic speed range was taken as a representative example of such effects since it lends itself easily to simple and...

Measurements of skin-friction using surface-pitot tubes in free flight at supersonic speeds

Surface-pitot tubes have been used to measure local skin-friction in free-flight. Measurements were made at 10 stations on a simple delta-winged model flying at zero lift at Mach numbers between 2.2 and 1.2. This Note describes the design and development of the instrumentation and the methods employed to analyse the experimental data. Good...

Free-flight measurements of the drag and longitudinal stability of a transonic M-wing aircraft

Free-flight tests have been made on a model of an M-wing aircraft designed to cruise at M = 1·2 with a subsonic type of flow on the wing surfaces. Results are presented for the zero-lift drag and longitudinal stability characteristics over the Mach number range from 0·9 to 1·3. It is shown that the design aims have been achieved in that no...

Some properties of wedge section aerofoils at supersonic and hypersonic speeds

Heat-transfer and pressure measurements on the upper surface of a delta wing at incidence at mach numbers between 2.0 and 3.6

Measurements of the distribution of heat-transfer coefficient and static pressure have been made in free flight on the flat upper surface of a sharpedged delta wing of aspect ratio 1 (76º leading-edge sweepback) at 14° incidence. Two configurations were tested differing only in edge angle between upper and lower surfaces, being 26.50 and 900...

A method of fatigue life prediction using data obtained under random loading conditions

Preliminary tests have been made to investigate a method of fatigue life prediction in which fatigue data obtained under a simple form of random loading are substituted for the data hitherto obtained under sinusoidal test conditions. The results of this work show a significant increase in the accuracy of prediction, but it is evident that...

Cumulative damage in fatigue with particular reference to the effects of residual stresses

In this Report factors affecting the accuracy of Miner's Rule are discussed. An investigation is also described of thecumulative damage behaviour of DTD, 5014 aluminium alloy lug specimens using random loading. It is concluded that the deviations from Miner's Rule observed in the investigation can be ascribed mainly to the act ion of residual...

An experimental study of the stress histories at stress concentrations in aluminium alloy specimens under variable amplitude loading sequences

In this paper an investigation is described of residual stresses associated with plastic deformation at a stress concentration in an aluminium alloy specimen. Local stresses were determined, by an indirect method, under a variety of sequences of loads which included peaks high enough to cause local yielding. Sequences at bath zero and a positive...

Fatigue behaviour of pin-loaded lugs Ln BS 2L65 aluminium alloy

Fatigue tests have been carried out on lugs of BS 2L65 aluminium alloy loaded by steel pins under constant amplitude (CA) and narrow band random (NBR) loading over a range of mean stresses and for different values of pre-stress. Life estimations for the NBR tests were made using Miner's rule. The relative fatigue performance under CA and NBR...

Frictional force measurements on fretted specimens under constant amplitude loading

There is substantial evidence that the damaging effect of fretting depends upon the magnitude of frictional forces between fretted surfaces. Accordingly a programme of measurement of frictional force between aluminium alloy specimens and steel fretting pads under constant amplitude loading has been carried out. The measurements have been used,...

Standardised fatigue loading sequences fro helicopter rotors (helix and felix), Part 1: background and fatigue evaluation

Helix and Felix are standard loading sequences which relate to the main rotors of helicopters with articulated and semi-rigid rotors respectively. The purpose of the loading standards is, first, to provide a convenient tool for providing fatigue data under realistic loading, which can immediately be compared with data obtained by other...

Waveforms in fretting fatigue

The magnitudes am directions of the frictional forces must be considered in any fracture mechanics analysis of crack growth under fretting fatigue conditions. A simple nonlinear friction model has been developed which relates the waveforms of the frictional forces to those of the applied forces when fretting occurs. It is shown that the...