Cranfield Institute of Technology - Memoranda (1970- 1974)https://reports.aerade.cranfield.ac.uk/handle/1826.2/48662024-03-28T16:08:34Z2024-03-28T16:08:34ZThe influence of flow parameters on minimum ignition energy and quenching distancehttps://reports.aerade.cranfield.ac.uk/handle/1826.2/48722023-09-13T00:53:54ZThe influence of flow parameters on minimum ignition energy and quenching distance
Experiments have been carried out on the effects of pressure,
velocity, mixture strength, turbulence intensity and turbulence
scale on minimum ignition energy and quenching distance. Tests
were conducted at room temperature in a specially designed closedcircuit tunnel in which a fan was used to drive propane/air
mixtures at subatmospheric pressures through a 9 cm square working section at velocities up to 50 m/s. Perforated plates located at
the upstream end of the working section provided near-isotropic
turbulence in the ignition zone ranging from 1 to 22 percent in
intensity, with values of turbulence scale up to 0.8 cm.
Ignition was effected using capacitance sparks whose energy and
duration could be varied independently.
Aeroplane design study STOL airliner (A71). Part 3- low speed lift and controlhttps://reports.aerade.cranfield.ac.uk/handle/1826.2/48682022-05-09T10:29:08ZAeroplane design study STOL airliner (A71). Part 3- low speed lift and control
The potential application of advanced forms of aircraft
control to civil operation appears to be capable of being split
into two areas. First, those aircraft which are very large,
whose rotary inertia tends to reduce the effectiveness of
conventional controls. Second, those aircraft whose
specification dictates that the aeroplane be flown at very low
speed. Again conventional controls become inefficient due to
decreased aerodynamic efficiency.
The second category of aircraft has been considered in
the form of an STOL aircraft. The control problems of an STOL
aircraft with a 2000 ft runway capability (Ref.10) have been
examined. It has been found that the aircraft is unstable
and could require autostabilisation. None of the conventional
controls were satisfactory and each required augmentation.
The single strip crosswind requirement penalises the design
most heavily since this requires over half of the extra control
power necessary. The total augmentation for blowing air
amounts to an equivalent thrust of approximately 6700 lb.
This is equivalent to 11.5 per cent of the total installed
aircraft thrust.
A preliminary study of survival rates in civil aircraft accidents, 1966 - 1973, with particular reference to fire risk and fuel typehttps://reports.aerade.cranfield.ac.uk/handle/1826.2/48672022-05-09T10:29:08ZA preliminary study of survival rates in civil aircraft accidents, 1966 - 1973, with particular reference to fire risk and fuel type
To establish whether theoretical and laboratory safety advantages
of low volatily fuel, such as that of low rate of flame spread,
are reflected in aircraft accident 'statistics' a preliminary
study has been made of the ARB's world airline accident summary.
An advantage has been found in that the change to kerosine has
apparently halved the death rate in survivable accidents.
In all gas turbine accidents, including those where death was
probably due to impact not fire, the death rate seems to be 50%
higher with wide cut gasoline than with kerosine.
It has also been found that a higher proportion of gasoline
powered aircraft accidents involved impact death 1.1-1d that overall
the survival rate has remained virtually unchanged. A critical
examination of these preliminary findings, in the light of the
relevant accident reports, is planned.