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This paper aims to present stability analysis of a small pulsejet-powered airplane. This analysis is a part of a student project dedicated to designing an airplane to test valved pulsejet engine in flight conditions.

The panel method was chosen to compute the airplane’s aerodynamic coefficients and derivatives for various geometry configurations, as it provides accurate results in a short computational time. Also, the program (PANUKL) that was used allows frequent and easy changes of the geometry. The evaluation of dynamic stability was done using another program (SDSA) equipped with means to formulate and solve eigenvalue problem for various flight speeds.

As a result of calculations, some geometry corrections were established, such as an increase of the vertical stabilizer’s size and a new wing position. Resulting geometry provides satisfactory dynamic and static stability characteristics for all flight speeds. This conclusion was based on criteria given by MIL-F-8785C specifications. This paper presents the results of the first and the final configuration.

The results shown in this paper are necessary for the continuation of the project. The aircraft’s structure was being designed in the same time as the calculations described in this paper proceeded. With a few modifications to make up for the changes of external geometry, the structure will be ready to be built.

The idea to design an airplane specifically to test a pulsejet in flight is a unique one. Most RC pulsejet-powered constructions that can be heard of are modified versions of already existing models. What adds more to the value of the project is that it is being developed only by students. This allows them to learn various aspects of aircraft design and construction on a soon-to-be real object.

To recover the growing deficit between American and near-peer mobile artillery ranges, the US Army is exploring the use of the M982 Excalibur munition, a family of long-range precision projectiles. This paper aims to analyze the effectiveness of the M982 in comparison to the M795 and M549A1 projectiles to further the understanding of what this new asset contributes.

Based upon doctrinal scenarios for target destruction, a statistical analysis is performed using Monte Carlo simulation to identify a likely probability of kill ratio for the M982. A values-based hierarchical modeling approach is then used to differentiate the M982 from similar-type projectiles quantitatively in terms of several different attributes. Finally, sensitivity analyzes are presented for each of the value attributes, to identify areas where measures may lack robustness in precision.

Based upon a set of seven value measures, such as maximum range, effective range, the expected number of rounds to destroy a target, and the unit cost of a munition, the M982 1a-2 was found to be best suited for engaging point and small area targets. It is noted, however, that the M795 and M549A1 projectiles are likely better munition options for large area targets. Hence, an integrated targeting plan may best optimize the force’s weapon systems against a near-peer adversary.

The findings provide initial evidence that doctrinal adjustments in how the Army uses its artillery systems may be beneficial in facing near-peer adversaries. In addition, the values-based modeling approach offered in this research provides a framework for which similar technological advances may be examined.

A Theoretical Approach to Assessing the Thermodynamic Process Within the Combustion Chamber of the Propulsive Duct, an Examination of the Potential of the Duct with Special Reference to the Application of Feedback and Spark Discharge Techniques. Development of the propulsive duct has been retarded by the absence of a suitable theoretical analysis. This paper, based on four years of experimental investigation by the author, discusses the problems involved and puts forward a theory which closely follows practical results. The theory is then used to examine the potential of the duct and it is shown that by applying feedback and spark‐discharge techniques, a low specific fuel consumption and unlimited thrust, outside the audible range, is theoretically possible. Finally, it is shown that the marriage of the duct to electrical power generated from atomic sources otters attractive possibilities for V.T.O.L. and aircraft propulsion of the future.

An annular combustion chamber having air jackets around its inner and outer walls, and having in combination a plurality of liquid fuel nozzles mounted in equi‐spaced relationship and circular formation around one end of the chamber with the axes of the nozzles lying centrally between the inner and outer walls of the chamber, air‐swirling means surrounding each nozzle, a hollow annular nosepiece extending from the said end of the chamber, and shaped to direct air to the air jackets, an annular air entrance situated adjacent to the outer end of the nosepiece, an annular hood surrounding the nose piece and forming therewith air passages leading from the air entrance to the air jackets, and a plurality of air scoops situated in equi‐spaced positions within the nosepiece and leading from one of the air passages to the air‐swirling means around the fuel nozzles.

The effect of moncyclic versus polycyclic aromatic components in JP‐5 fuels, on total flame radiant energy was investigated. Variations in aromatic type and content within the JP‐5 specification had an effect on flame radiation. Polycyclic aromatic fuel blends burn with higher flame emissivities than the monocyclic blends of comparable ASTM Smoke Point. Radiant heating of metal parts was shown to be a function of their location in the combustion chamber. The use of low‐luminosity fuels gave major reductions in liner temperatures in the J‐57 combustion chamber.

After‐burner flames do not have to be stabilized by means of ba'nes; and indeed the drag which solid flame‐holders exert on the tail‐pipe gases, even when re‐heat is not in operation, render them undesirable elements to have in a jet engine. For this reason there has been considerable interest in recent years in the use of air‐jets as flame‐holding devices; these have the advantage that they can be turned off when not in use. The first suggestion of this kind known to the reviewer was made in a S.N.E.C.M.A. patent of about 1953; experimental studies were carried out at Imperial College, the jets in question emerging from slots in the wells of the duct carrying the co bustible gas the method was found to work quite well. More recently, work in United States laboratories has concentrated on the use of jets injected in a direction opposed to that of the main stream; the present issue contains a report from the Stanford Research Institute on one investigation of this type. The reviewer has not heard of any practical application of jet flame‐holders so far; but certainly sufficient laboratory progress has been made to justify the attention of engine designers.

A service door and emergency exit structure for aircraft having an outer surface formed with a service door opening therein, an annular service door receivable in said service door opening having an emergency exist opening therethrough surrounded by said door, flange means projecting from the periphery of said door in overlapping relation to the inner face of the surface portion of the aircraft surrounding said service door opening, resilient scaling gasket means carried by said door intermediate the overlapping portion of said flange and said inner face of the surface portion, hinge means within the aircraft connected between said door and the inner face of said surface portion for swinging said frame inwardly out of said service opening and outwardly into said service opening, retractable latch means carried by said door, strike members carried on the inner face of the said surface portion receiving said latch means for retaining said door in said service door opening, an emergency door panel overlapping the outer surface of the door around its periphery, an annual panel supporting frame secured to the inner face of said door panel, receivable in, and removable out of said emergency exit opening in said service door, scaling gasket surrounding said emergency exit opening between the service door and the periphery of the emergency exit panel, said latching means comprising retractable locking bolts each having an actuator receiving recess at its inner end facing inwardly of the aircraft, a plurality of bolt retracting actuators slidably carried by said emergency exit door panel structure each having an actuating head received in one of said recesses, leaf spring means carried by said bolts for yieldably retaining said heads in said recesses, manually openable actuator means carried by said emergency door panel and connected to bolt retracting actuators for retracting said actuators to unlock said service door, separate locking members carried by said emergency door panel for locking engagement with said service door, emergency exit panel release actuator means carried by said emergency exit panel for unlocking said separate locking members to release said emergency exit panel from said service door including flexible actuating connectors connected between said last‐mentioned actuator means and said separate locking members, whereby release and outward displacement of said emergency exit panel from said service door disengages the said heads of said bolt retracting actuators from the recesses in the retractable service door locking bolts.

This study aims to achieve optimum flow separation control for a road vehicle using a reverse flow fan on rear side.

A full-length reverse flow fan array (fan’s air speed is 50% of the car’s speed) is attached throughout the width of the vehicle at rear edge corner.

The reverse flow fan array positioned at rear edge of car pushes the airflow against the car’s rear window. It creates the recirculation region and alters the pressure distribution. This reduces the lift coefficient by 150%, which becomes the downforce and reduces the drag coefficient by 22%. As the car speed increases, fan speed should also be increased for effective flow control.

This active flow control method for 3D Ahmed car body has been studied computationally at low speed (40 m/s).

This design increases the downforce, thus gives better cornering speed and stability, and decreases the drag which improves fuel efficiency. It can be used for effective flow control of cars (hatchback/sedan). The findings can be applied to the bluff bodies, road vehicles, UAV and helicopter fuselage for flow separation control.

The fan array is attached on car’s rear side, which blows air against the car’s rear window. It alters the pressure distribution and aerodynamics forces favorably. But the existing high-speed fan used in a sports cars sucks the air from bottom and pushes it rearward, which increases both the traction force and drag.

A Theoretical Approach to Assessing the Thermodynamic Process Within the Combustion Chamber of the Propulsive Duct, an Examination of the Potential of the Duct with Special Reference to the Application of Feedback and Spark Discharge Techniques. The type of valve of greatest importance to successful duct design is one which is synchronized to the pressure fluctuations within the combustion zone. Although there have been a number of proposals for mechanically linked valves (indeed the normal internal combustion engine works on this principle) and rotary valves, these have severe limitations at the higher frequencies and are generally impracticable for the application under review. This section will therefore concentrate on the mechanical reed‐type valve which, theoretically, need have only one moving part, i.e. the dynamic metal reed, and the aerodynamic valve which relies upon the interaction of two gas dynamical vibrations and has no moving mechanical parts.