Search Results

This paper examines a number of the methods available for producing high lift as required by today's STOL aircraft and compares these methods on the basis of maximum lift coefficient. Most of the efforts to generate additional lift are directed toward providing favorable conditions for the boundary layer to prevent flow separation or to increase the projected wing area. Ideally a high lift system should make maximum use of both of these possibilities. High lift coefficients are well within the current state-of-the-art and have been so demonstrated by numbers of research aircraft. However, the resulting problems of control criteria and handling qualities requirements still present an obstacle to the increased utilization of high lift systems.

The commuter or third level airline service is a stable, rapidly growing and necessary part of the United States transportation system today. Much of the success of operators in this service is due to recognition of the needs of the communities they serve and tailoring service to fill these needs. Modern equipment with profit-producing potential, a hub-and-spoke traffic pattern with emphasis on non-stop routes and proper promotion are keys to success.

This paper illustrates in the context of the operational requirements for a business aircraft, the dependence of airframe design and powerplant choice on aerodynamics. The Handley Page Jetstream twin turboprop airplane at 12, 500 lb A.U.W. is used to illustrate this thesis. Performance and layout of executive and high-density versions, 300 mph cruising, stage ranges up to 2000 miles, payload up to 18 passengers and 2 crew, and low first and running costs, are covered. Among subjects discussed in detail are: 1. Choice of wing area, planform and t/c ratio. 2. Choice of engines and propellers. 3. Modification of wing section to improve flow near trailing edge. 4. Tunnel tests to eliminate hysteresis with double slotted flap. 5. Tail unit design. The powerplant, Turbomeca Astazou XIV and Hamilton Standard propeller, is described. The direct control of propeller blade angle, characteristic of the Astazou, is shown to simplify piloting and increase safety.

This paper looks at the engineering aspects of the business aircraft industry and makes certain recommendations concerning the engineer and his continued growth. A four point program is proposed to establish the environment necessary for continued significant engineering contributions.

The current position of the two-stroke cycle aircraft engine is described with respect to competitive type powerplants, including a brief historical background and information on some of the latest designs. The two-cycle case is substantiated with arguments and data showing why it should still be considered for the lower power ranges.

The Gulfstream II business jet is a low wing aircraft of moderate sweep featuring a T-tail arrangement and two aft-mounted turbofan engines. The paper outlines aerodynamic development of the configuration and control system, highlighting significant design decisions and aerodynamic characteristics with appropriate experimental data including force, pressure, and flow visualization results. Aerodynamic design considerations included: wing optimization to meet the requirements of high and low speed performance and a pitch-down stall break at all flight conditions while providing adequate fuel volume; nacelle-pylon-wing relationship for optimum drag, engine characteristics, and airplane balance; and an empennage arrangement providing satisfactory stability and control at all conceivable flight conditions. The Gulfstream II configuration provides strong aerodynamic resistance to inadvertent secondary stall entry and more than adequate recovery capability.

New packaging concepts for avionics equipment are evolving as a result of extensive use of microcircuits and thin film circuits. These components, essentially planar in configuration, have naturally led to the development of new planar packaging systems. A system of this type currently being implemented uses planar circuit boards of a unique new design and also provides a method of packaging these boards in separate planar sections. Two or more of these sections, each with its own connector and dust cover, may constitute a complete airborne function such as VOR or VHF communication. The sections, which are shorter than standard ARINC units because of increased packaging efficiency, also facilitate equipment installation in smaller aircraft.

The electronics package for a Category II qualified business jet aircraft and the function of the various components of the system are described. These components include: dual Collins 51-RV-l VOR/ILS/G. S. receivers which provide and utilize beams along which the aircraft descends for a safe approach; a Collins AL-101 radio altimeter to determine altitude; dual flight directors for automatic and manual approaches; and a Collins 54W-1 comparator warning system, to name a few. A general rather than a technical approach is used.

Microelectronic devices are the natural next phase in the evolutionary cycle which comprises miniaturized, transistorized, and solid state components. Microelectronics refers to a miniature device that will make it possible to manufacture electronic equipment smaller than has been done in the past. Of greater significance than the smallness of the devices is the reliability, maintainability, and ultimately the cost factors of such devices. This paper describes various microelectronic devices currently in use and presents photographic illustrations. New products will be manufactured and marketed which will make far greater use of such devices, and, in many instances, cause a significant change in design concepts used to achieve the functions of avionics in General Aviation aircraft.

The versatile, small utility, business and private aircraft often operates from strips where external power and engine preheat are not available. Starting tests performed at 0 F have shown that with all engine conditions normal (standard SAE 30 aircraft engine oil, external power source, and functioning prime system), an engine start is unlikely. Faster cranking speeds are known to contribute substantially to improved starting, and can be obtained through the use of less viscous lubricating oils. An SAE 10W30 aircraft engine oil, compounded to promote easier cold weather starting and offering adequate protection at normal operating temperatures, is discussed and comparisons are drawn between this oil and other available multiviscosity oils. Results from cold weather starting tests as well as a service test program performed to support the use of the 10W30 oil under normal hot weather operating conditions are presented.

A number of design parameters are traded off in the design of an airborne weather radar system. The inter-relative effects of design tradeoffs can be meaningfully approximated by application of the standard range equation which takes into account such items as peak transmitter power, width of the transmitted pulse, target area and reflectivity characteristics, transmitter wavelength, antenna gain, and the receiver overall noise figure. Selection of that radar system which is best suited to the particular aircraft to be equipped not only increases the utility of the aircraft, but also the safety of operation within given weather margins. Optimal allowances made for such installational limitations as reflector size, radome design, and temperature environments enhance both the performance and the reliability of the radar.

New electronic devices such as the silicon rectifier, transistor, silicon controlled rectifier, and miniature electromagnetic relay are changing the complexion of aircraft d-c generating systems. Their application has resulted in the introduction of a static equivalent of the familiar carbon pile regulator and of the overvoltage relay, as well as a unique protector against feeder faults. As developed by General Electric, these new products provide better voltage regulation, improved engine starts, and better system protection. They are smaller, lighter, and longer-lived than the older electromechanical devices. Brushless d-c generators, also made possible through the use of modern semiconductors, bring relief from old-time maintenance problems of brush and commutator wear. All these new products represent new trends in aircraft d-c systems.

Smaller jet aircraft have created a need for jet fuel facilities at smaller airports. Principles of fuel handling have been developed to prevent known jet fuel contaminants from being delivered into aircraft. Typical airport facilities have been developed to fulfill requirements for safety, fuel quality, and ease of operation. If a jet fuel system is designed and operated properly, clean, dry fuel can be consistently delivered into aircraft.

At the present time, there are four basic kinds of oils available for utility aircraft piston engines; two of these can be considered major types and two minor, but of considerable interest. These are: nonadditive straight mineral oil; ashless dispersant mineral oils; metallic additive detergent mineral oils; synthetic oils. This paper discusses the merits of each of these major types of oil and compares their relative advantages in several categories. The paper also develops some of the reasons why the ashless dispersant mineral oils have made such gains in usage since introduced to the market in 1958. There is also a discussion and clarification of the terms “dispersant” and “detergent” as applied to additive oils.

The status of the rotating combustion aircraft engine program at Curtiss-Wright as of the fall, 1966, is presented. Related developments which led to present configurations are briefly discussed and likely directions for the future are mentioned. This prior work included cumulative test time of 34,000 hr on one to four-rotor engines covering a displacement range of 445/1; the development of durable, efficient components; feasibility demonstrations of air cooling and heavy fuels operation; and field testing in automobiles, boats, and generating sets. This background leading to the current JP fuel-injected 310 hp engine (RC 2-90) is developed to show that today's RC engine offers propeller driven and rotary wing aircraft a new powerplant approaching the size, weight, and smoothness of the gas turbine at reciprocating engine fuel economy and cost.

The term “Guided-light” applies to a new concept of internal light utilization applicable primarily to opaque-faced, “edge-lighted,” plastic panels. Manufacturing techniques based on this concept make possible the production of “one-piece” illuminable cockpit and control console panels that have unprecedented efficiency and “light-throw” yet retain the dimensions and conventional appearance of the “single panel” types. It is estimated that Guided-Light panels require less than 25% of the number of embedded lamps that are now used in state-of-the-art, embedded lamp, single panels. Some of the techniques of “guided-light” light distribution are related to those that have been developed for the Duo-Panel but others are unique. This paper lays the ground work for early industrial application to aero-space indicating instruments. Optical efficacy of candidate combinations of materials may be determined through use of the curves presented.

This paper describes the development of a packaging technique using the new dual in-line package. Part one tells why this package was developed and gives some advantages this technique has over present trends in packaging. Part two gives a complete explanation and description of the component parts of the package. The third part elaborates on the heart of the package, namely the interconnection matrix. Details are given on converting from a systems logic diagram to a graphic format used in the development of the matrix layout. Part four explains the step by step procedure used in manufacturing the dual in-line module on both the prototype and production level. The fifth and final part of the paper tells of other packaging techniques using as a basic building block, the internal parts of the dual in-line module.

The need for positive and definitive identification of questionable microwelds is not due to the high number of poor welds made in any production. The need stems from the fact that visual inspection criteria are neither sufficiently uniform nor dependable to guarantee 100% reliability where absolute reliability is a real requirement. At Raytheon, a Weld Research Program has used the technique of IR monitoring to improve the accuracy of diagnosis of welding inspectors. An experimental program has verified that infrared can be useful, not only in welding control, but as a good monitor of weld quality without the necessity of using it to control. The concept of IR monitoring can be extrapolated into structural welding for purposes of continuous 100% quality determination, control, and flaw detection.

Factors to be considered in selection of fuel for the auxiliary power system are discussed along with the performance of various fuels or propellants. The non-air breathing systems covered in this paper are considered an integrated assembly of four basic subsystems - energy source, energy converter, power conditioning, and heat sink. Advantages and disadvantages of both solid and liquid propellants are reviewed. Because weight and size considerations are of prime importance in auxiliary power units, a theoretical performance in the way of minimum specific propellant consumption is presented. The paper concludes with presentation of a possible problem an APS must undergo, and its solution.

Acceptance of the flat pack as a standard configuration for integrated circuits has stimulated development of new interconnection techniques which necessitated development of new criteria and controls for these techniques. One method being utilized at Martin-Denver is a hot gas soldering process in which the solder joints are made by passing the printed circuit board containing the flat packs under hot gas jets. Specification of this process for a possible space application necessitated development of inspection criteria and controls to ensure the required joint reliability. This was accomplished concurrently with development of the soldering process and qualification method.