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Test report no. PLBO/12: comparison of modified forms of PERPRO carbide grade TO 348 when machining EN 9
No full textTools of TO 3)48/ RD60, RD61, RD62, RD63 and Standard were tested to
0.030 in. flankwear when machining EN 9 at 600 fpm with 0.010 in/rev.
feed and 0.10 in. depth of cut. The results showed that while no one
grade was outstanding RD61, RD62 and RD63 gave an all round better
performance than the other two grades
The behaviour of the aluminium alloy RR58 under combined creep and fatigue conditions. Part 1, the hydraulic combined creep and fatigue machine
No full textExperimental techniques used in the high temperature heat-treatment of some tungsten-thoria alloys
No full textThe high temperature apparatus developed in the Department of
Materials for the torsional creep testing of graphite at temperatures up to
3000 oC has been utilised to heat-treat tungsten-thoria alloys at temperatures
up to 2500 oC. Modifications to the torsional loading system have enabled
some of these heat-treatments to be carried out under an applied stress
Room temperature torsional fatigue properties of an iridium: 5% tungsten alloy
No full textIntroduction
Fine wires of an iridium-5% tungsten alloy have been developed as
a potential material for use in springs operating at high temperatures.
Their suitability for such applications will to a considerable extent
depend on satisfactory fatigue properties. The Materials Department of
The College of Aeronautics was approached with a view to determining
these torsional fatigue properties. This report covers preliminary work
into this problem, namely the torsional fatigue behaviour of 0.020 ins.
diameter wires at room temperature
Factors affecting punching speeds of hollerith operators. Mechanical factors outside the control of the operators
No full textOne of the major influences governing punching speeds is the operator's
reaction to what she regards as the innate stiffness of the punch.
This Note reviews those factors which are attributable to the machine
rather than the operator, and seeks to assess their relative importance
from the viewpoint of their effect on punching performance.
On the basis of a number of tests using a standard keyboard under
normal operating conditions and employing motion-study techniques,
the following conclusions are reached respecting the influence on
punching speeds of the various factors.
1. The stroke of the kay has very little influence on punching
speeds
2. The spacing of the keys has an appreciable effect on punching
speeds
3. The so-called 'stiffness' of the punch is often not stiffness
in the mechanical sense, but is a physiological reaction in the
operator to different key-top pads
4, A certain amount of variability of pressure is always inherent
in the machine, and operators are, within certain pressure
ranges, extremely sensitive to such variability.
An Appendix to the Note describes the key-punch 'Pressure Pick-up'
which was designed for the tests
Some bearing materials under high pressures at low rotational speeds
No full textA series of tests were carried out, in the Design
Department of the College of Aeronautics, on plain journal
bearings, at higher pressures than are normally encountered in
engineering practice. Pressures of 40,000 lb/in.2 were realised
with a rubbing speed of 1.1 ft./min. Comparison between the
various materials tested was effected by continuously rotating
the bearings for fixed periods under various loads while friction
and wear were measured periodically. The most outstanding
combination was S.90 Chromium-plated running in a Hidurex Special
bearing. Some other materials, listed in paragraph 8, were also
found to be suitable although not so wear-resistant.
All the materials tested suffered same surface damage
which, in general, proved not to affect the bearing performance.
An attempt is made to explain the behaviour of the
bearings and thus indicate possible further materials which might
prove suitable
Water injection in the normally-aspirated piston engine
No full textThe injection of water into a spark-ignition piston engine tends
to reduce both the power and the tendency to knock. Because of the
latter effect the conditions of operation can be made more severe in order to realise overall gains in power and economy.
Injection of water at different points in a single-cylinder
engine shows the most practicable method to be fine atomization into
the inlet manifold
Water flow requirements are found to be directly
proportional to the manifold absolute pressure, and a commercial
type of water injection unit designed on this basis is described and
road-tested.
An attempt has been made to estimate the distribution of water
to individual cylinders of a multi-cylinder engine, and the effect
of water up on engine components is examined
Property requirements for liquid rocket propellants
No full textAn analysis is made of the properties necessary for liquid
rocket propellants to give effective performance with acceptable
handling. Typical propellants are examined against this requirement
background, and their relative suitability assessed
