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Some experiments on the flow in the boundary layer of a 45 degrees sweptback untapered wing of aspect ratio 4
No full textVisual methods have been used together with a yawmeter to illustrate conditions of flow in the boundary layer over a sweptback wing. It was found out that at moderate incidences a marked outflow in the boundary layer was developed. Continues
The unsteady aerodynamic forces on deforming, low aspect ratio wings and slender wing-body combinations oscillating harmonically in a compressible flow
No full textA method is presented whereby the 'Slender Body Theory' can be applied to the determination of the unsteady aerodynamic forces acting on slender wings and wing-body combinations experiencing harmonic deformations in a compressible flow. The analysis holds for subsonic and supersonic speeds, subject to restrictions which are stated and discussed
Space weather warning system
No full textStudents of the MSc course in Astronautics and Space Engineering 2011–12 at Cranfield University
studied a space weather warning mission for their group project. The mission was inspired by the
Space Weather Diamond mission proposed by St. Cyr et al. in 2001. This report summarises the
students’ work and their findings.
The report consists of an overview and discussion of the technical work of the project and a
compilation of the executive summaries which describe the specific contributions of each student.
Two mission concepts are developed to provide at least 2 hours’ warning of severe space weather
events. These are an augmented Space Weather Diamond mission and a Circular Heliocentric
Constellation: both missions have advantages which justify further work
Plastic tools for aircraft production
No full textThe most important current problem associated with aircraft
production is the necessity for a reduction in the time
cycle from design to completion of the first production machine.
Tool manufacture is one aspect in which improvement is desirable.
The use of thermo- and setting-plastics for drop-hammer
and double-curvature panel drill jigs is examined aver a wide
technical and economic field, in order to establish a sound
foundation for investigating the suitability of plastics for
tooling. Tools were designed to isolate the variable parameters
and a study of their behaviour has commenced , dth the assistance
of high-speed filming, to ascertain the limitations of the various
materials. Casting resins are preferable for both punches and
dies although the laminated form, in addition to being the better
type for pcnel drill jigs, appears to be the most satisfactory
die material available at present.
It was concluded that plastics facilitate easier and
cheaper tool production titan is practicable with zinc and, for
the tools produced, reduce the necessary time cycle of production
by about 80 per cent with a corresponding reduction in the man.-
hours required.
In the tests made to develop suitable plastic tools,
attention was concentrated on the development of a suitable
slightly flexible punch, and a rigid diet following the most
promising indications of this work.
It was found that Tenite Medium Bard was a good punch
material with a life of over 1,000 components, the springback
differing from that of a Kayen Alloy punch by less than one
degree for all the tool shapes tested. The economic savings
are approximately cost 87 per cent, man-hours 84 per cent, and
time cycle 81 per cent. It should. be noted that the ;lunch and
die selected for this test was a severe forming case of a double
curvature bead.
The most satisfactory die developed was manufactured
from Aralditc D resin, glass fibre and french chalk. Limited
tests with a Tenite M.H. punch gave satisfactory results for
short runs, and in all probability longer runs could be made.
The economic reductions effected were; cost, 68.5 per cent and
man-hours, 86 per cent
Reaction-resisted shock fronts
No full textIt is shown that shock waves whose structure is determined solely by the effects
of chemical reactions (reaction-resisted shock fronts) are possible and completely
analogous to relaxation - resisted waves. A single dissociation reaction is considered
and numerical results indicate that such waves could be observed experimentally.
Bulk viscosities equivalent to reaction effects are possibly 10[to the power of 2] or more times shear
viscosity values. (Examples are based on Lighthill's ideal dissociating gas)
Statistical parameters in planning aero-engine production
No full textThis report considers the estimation of statistical parameters and their
application to production planning in the aero-engine industry. A similar pattern
of behaviour to that already recognised as existing in the airframe industry is
found to operate, though there are indications of quantitative differences.
The build-up time to the planned peak rate of production in a particular
situation is found to be about eighteen months but with variation between firms.
The reduction in operator performance time, which occurs with repetition during
the build-up period and afterwards, is discovered to be present in machining as
well as assembly, but to a lesser extent. The logarithmic function generally
descriptive of such a tendency is found to fit the actual man-hour content values
rather than the cumulative average ones. The relationship between the logistic
of output and the logarithmic function is established and made use of to estimate
labour requirements from the commencement of production onwards.
In addition to the above consideration of production variables, examples
are given of the use of engine performance ratings to estimate costs. Finally,
because of the importance of planning to productivity, a typical production
programme has been included
Aircraft design studies - E67 tilt-wing executive aircraft
No full textThe E67 design was for a vertical take off and landing
aircraft for executive use. Vertical flight capability was
achieved by using the tilt wing concept. In the initial
version of the design power was provided by two Rolls Royce
H1400 Gnome turbo shaft engines driving two 16 ft. diameter
propellers. Cross shaft interconnection between the propellers
was included in the layout. Subsequently the need for four
engines to cater for an engine failure condition in vertical
flight became apparent. The pressurised cabin was designed to
accommodate up to 18 passengers in a high density feeder role.
Conventional design techniques were used throughout.
A market survey showed that the design had significant
advantages relative either to a helicopter or a twin jet
executive type (Reference 3)
Test report no. PLBO/15: field tests of PERPRO tips grade RD107 copy turning steel B.S.4
No full textSUMMARY
A batch of 232 Rammer Butt Stems were machined at P. and V. (Mining
and Engineering) Ltd., with alternate tips of SIT and RD 107. The results
showed that under the same cutting conditions the RD107 gave more pieces per
edge than did the S1P. It is suggested that further field trials should be
carried out to confirm this result
Characteristics of the high temperature mechanism of creep and recovery in graphite
No full textThe research reported in this document has been made possible
through the support and sponsorship of the U.S. Department of the Army,
through its European Research Office. This report, not necessarily in
final form, is intended only for the internal management use of the
Contractor and the U.S. Department of the Army
The replica strain gauge technique
No full textSurface deterioration and dimensional stability tests have been carried
out on the low melting point replication alloy described in the first
report. A range of alloys for the replication of surfaces at temperatures
in the range 120 - 150°C has been prepared and evaluated. Preliminary
studies of a cold pressing technique using fully annealed commercial
purity aluminium as the replication material have shown that the technique
has considerable promise for application over a wide range of temperatures