Search results

This is our report on this first international assembly of Aircraft Maintenance and Engineering, held in Zurich 6th–9th February 1979. This was AIRMEC 79 — and, as was foreseen in our Comment in the January issue, the significance of this innovation among aviation occasions was taken up by thirty‐six countries who sent 276 delegates to the convention, which was supported by the Exhibition, attracting 112 exhibitors from 17 countries. There is every chance that this event will take its place with Farnborough, Paris and Cranfield as a regular feature of the aviation scene and of considerable interest to all engaged in aircraft maintenance. The organisers did announce at the end of that Show that AIRMEC 81 would take place, again in Zurich, in February of that year. And perhaps it is interesting to comment at this stage about the decision to return to Zurich. While it might be said that the event was a success, the fact that the convention was held in a venue separate from the Exhibition, did have some disadvantages and the consensus among the exhibitors was that this did discourage many of the 2260 in attendance from really taking in the Exhibition. Perhaps the only exception to this were the Chinese whose delegation spent almost all of every day in the Exhibition halls, visiting every stand and spending considerable time at each one.

The Industrial Acoustics Company has been designing and manufacturing noise control equipment for Aviation engine test facilities and ground run up beds for over 20 years and during this period has successfully “silenced” most military and commercial engines. Much of IAC's work has been in the military field, and as engines have grown more complicated, and contractural conditions more involved, procurement bodies have become increasingly concerned about the splitting‐up of the various engineering disciplines necessary for the total design and manufacture of such facilities.

The purpose of this paper is to demonstrate the aerodynamic behavior of a supersonic combustion test bench (SCTB) components, as the transition piece and the combustor of a scramjet (supersonic combustion ramjet), manufactured by 3D printing or additive manufacturing (AM).

For the dimensional and structural analysis of the manufactured models, a portable 3D scanner was used to generate the mesh of its dimensions, and to compare them before and after the experiments, a roughness measuring system was also used to verify the roughness inside the models before and after the tests, as roughness is an important parameter because it directly affects the boundary layer. For the visualization of the flow, the non-intrusive schlieren optical technique was used.

The experiments were carried out on the SCBT for Mach 2 flows, using the manufactured prototypes and showed that there was no structural and dimensional change of the model after the test batteries. It was found that the roughness presented by the material did not affect the quality of the flow generated. This shows that the investigated material can also be applied in experiments with supersonic flow.

This paper presents that it is possible to use in ground test facilities, for the studies of supersonic flow (in cold condition), pieces and models manufactured by 3D printing without affecting the quality of the flow generated during the experiments. This study presents a new perspective to approach AM applied in the studies of supersonic flows.

The AGARD series of books are now becoming well established as valuable contributions to the technical literature on aeronautics. The present book adds one more volume and some considerable support to the reputation of the series. It consists primarily of papers presented at a joint meeting of the Combustion and Propulsion and the Wind Tunnel and Model Testing Panels of AGARD. The object of the meeting was to review the recent developments in ground test facilities and their applications to engine design and development and to compare them with inflight testing.

The monitoring of water build‐up in hydraulic, cooling and lubricating oils is routinely carried out in many laboratories, using various Karl Fischer titration and infrared techniques. The complexity and specialized nature of these techniques does not lend itself to the more credible online, on‐site testing demanded by good predictive maintenance practices.

ROCKET and ramjet engines have not the universal application that gas turbines command and possibly on this account they have not had, until recent years, the development effort which gave such amazing results in turbine powered aircraft. Nevertheless, they have demonstrated quite dramatically in various parts of the world that they are power plants to be reckoned with. In Great Britain, their value for aircraft was appreciated somewhat belatedly and events have since decreed that the promise they showed should be smothered before it could become a vital fact. On the other hand their importance for missiles was realized at the conclusion of the 1939–45 war, but again they were not encouraged on anything like the scale that present events show would have been justified. Because of this lack of encouragement, British rockets and ramjets, instead of leading the world, as do gas turbines, are struggling hard to provide a modest rate of progress.

This paper describes a free‐piston driven expansion tube and its instrumentation. The facility is used to generate rarefied flows at speeds of approximately 10 km/s. Although the flow in the tube itself is in the continuum regime, rarefied flow conditions are achieved by allowing the test gas to further expand as a free jet into the facility's test section. The test flow is surveyed to provide bar‐gauge pressure measurements. Numerical simulation is then used to describe more fully the test flow properties. The flows produced are suitable for the aerodynamic testing of small models at superorbital speeds and should provide data that are suitable for the calibration of Direct Simulation Monte‐Carlo codes.

PICTURE THE CORPORATE HELICOPTER MARKET as a giant iceberg. It represents our accomplishments to date and also is the key to our future, provided we adjust our marketing methods.

The area behind the engine/wing junction of conventional civil aircraft configurations with underwing-mounted turbofans is susceptible to local flow separation at high angles of attack, which potentially impacts maximum lift performance of the aircraft. This paper aims to present the design, testing and optimization of two distinct systems of fluidic actuation dedicated to reduce separation at the engine/wing junction.

Active flow control applied at the unprotected leading edge inboard of the engine pylon has shown considerable potential to alleviate or even eliminate local flow separation, and consequently regain maximum lift performance. Two actuator systems, pulsed jet actuators with and without net mass flux, are tested and optimized with respect to an upcoming large-scale wind tunnel test to assess the effect of active flow control on the flow behavior. The requirements and parameters of the flow control hardware are set by numerical simulations of project partners.

The results of ground test show that full modulation of the jets of the non-zero mass flux actuator is achieved. In addition, it could be shown that the required parameters can be satisfied at design mass flow, and that pressure levels are within bounds. Furthermore, a new generation of zero-net mass flux actuators with improved performance is presented and described. This flow control system includes the actuator devices, their integration, as well as the drive and control electronics system that is used to drive groups of actuators.

The originality is given by the application of the two flow control systems in a scheduled large-scale wind tunnel test.

In order to give some proof that the criteria used in the design of airframes and undercarriages provided adequate strength for the landing case dynamic tests of the landing shock absorber system, and for service purposes of the whole aircraft, were required. At first simple drop tests were carried out, the surface being inclined if fore and aft loadings were required as well as vertical ones. With increasing payload requirements the possibility of reducing undercarriage weight was investigated, and drop tests modified to approximate more closely to the actual case. The contribution of wing lift was allowed for, and the loads due to spin up of the wheels simulated by driving them electrically in the reverse direction before the drop. The technique of tests on the North American AJ‐1 is described.