Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
THE OUTLOOK FOR GENERAL AVIATION Malcolm S. Harnei Senior Vice President, Technology Cessna Aircraft Company I will start by defining general aviation, because there seems to be a perception problem as far as this part of the business is concerned. It is defined as all aviation except military and air carrier. Consequently, it includes personal, sport, training, agricultural, air taxi, and business flying. For many years business flying has been the dominant portion of the field. Currently, the domestic fleet consists of l84,000 aircraft, of which 2600 are jets, 3300 turboprops, 23,000 piston twins, and l55,000 piston singles. The international fleet is just about half again as large. In the U.S., general aviation is currently providing about l5 to 20 billion passenger miles of premium transportation per year. That is about an order of magnitude less than the revenue passenger miles of the commercial airlines. However, general aviation is probably providing more essential passenger niles per year than the commercial airlines. Furthermore, this business transportation is vital to our economy and can only be supplied by general aviation. This condition has been brought about principally by the decentralization of industry and the move to get out of the overcrowded, unmanageable major cities. This trend of moving industry into large numbers of small communities will continue to expand the need for business aviation well into the future. The airline deregulation law and high fuel costs have combined to force the airlines to become extremely efficient transporters of masses of people over long distances. The reductions in air fares have generally caused large increases in traffic, crowded airplanes, and congested terminals. These factors make flying very unpleasant for the businessman and eliminate the possibility of working while traveling. In addition, as a result of the quadrupling of the costs of avia- 91
tion fuel, the ai.rli.nes can no longer afford to service their low load factor routes, which generally are to decentralized, industrial communities. For a few statisticsâof the country's l5,000 airports, less than 350 are served by the airlines. About 70 percent of all passengers enplane at the 25 major hub airports, with one-third emplaning at the top 5. Also, in the last 20 years airline service has been discontinued to over one-third of the cities once served by the airlines. Another condition that has built business aviation is the high load factor necessary to conserve fuel and achieve low airline fares. High load factors frequently mean leaving people at the gate. Since the businessman tries to minimize his time expenditure, he is most likely to be the last at the gate and the one to be left. After missing a couple of important business commitments, a corporate aircraft becomes a real necessity. Without the business aircraft we have had, our rapid industrial expansion of the past 30 years would have been completely impossible. In the future, they will be even more essential. Another service offered by general aviation is the air taxi or commuter aircraft. Reductions in service to smaller communities on the part of the airlines has created a large demand for this commuter service from the many business people and others who need it but either cannot afford or cannot justify aircraft ownership. Airline transportation on the long routes is one of the best bargains available today and will be even better in the future. In small communities there are large numbers of people who want to take advantage of the low cost, high speed air travel available at the major hubs, and this has created a very large demand for commuter operations. Agricultural aircraft have become a necessary tool in the supply of food for the world. There are roughly l0,000 such airplanes treating one-quarter billion acres per year. For example, the U.S. produces the world's lowest cost rice by using aircraft to prepare the soil, seed, fertilize, weed, and protect from pestsâall from the air. The only time farmers set foot in the rice fields is for the harvest. Another essential service is that of training new pilots for all flying purposes. Over 50,000 new pilots enter aviation each year from the general aviation training services. Also of importance are public services such as air ambulance and law enforcement. In addition to these essential transportation roles, general aviation has become a very significant factor in our economy. Figure l shows the growth in general aviation both in total airplane sales and in exports over the last l0 years. It has grown to 2.l billion in gross airplane sales, with a $600 million export sales picture in l979. That means that it has become a very significant business and plays an important role in our balance of trade. This is a business that if properly supported could grow even faster in the future. To give a more complete perspective of what general aviation has been doing the past l0 years, I have three figures that show the relative position as compared to the other categories of aviation. 92
Figure 2 is a comparison of sales of general aviation (GA) aircraft to military sales. The abscissa is the percentage of GA to military. You will note that in the past l0 years the gross sales have grown from 5 to l5 percent of the military sales. Most significantly, the export sales have grown from about l5 to over 50 percent of the sales level of military aircraft. Also important is the fact that these are true export sales. They are not government giveaways. The relationship to helicopter sales is shown in Figure 3. There has not been a very big change over the years; however, the fact that total sales are some 500 percent greater and export sales are about 300 percent greater gives a good idea of their relative economic importance. Figure 4 considers transport sales. We all recognize that commercial transports are one of this country's greatest assets in our balance of trade battle. Therefore, it is significant that general aviation sales relative to commercial transport sales have grown from about l2 to better than 25 percent. (One year we hit close to 50 percent.) On the export sales end of the business, we have gone from 5 to over l0 percent as much and a couple of years were better than l6 percent of the export sales of commercial transport. In summary, general aviation not only performs a number of very essential transportation roles, but has also become a vital and growing factor in our economy. I would like to recall one of T. Wilson's comments about the fact that our government should be supporting the winners. General aviation is not only a winner today, but it has the potential of becoming a much bigger winner in the future, if the technology is provided. Now, I would like to turn to what is needed in the general aviation field for this growth to continue. Safety is an area that needs some serious attention. It has received considerable public attention in the last year. Table l shows safety statistics on the basis of fatalities per l00 million passenger miles and is representative of the experience of the l970s. The airlines have set an amazing record of 0.04 fatalities per l00 million passenger miles. It is outstanding for all forms of transportation. In contrast, the overall general aviation average is about l6 per l00 million, or 400 times worse than the commercial airlines. Even the much maligned passenger car fatality rate, which has dropped considerably in recent years with the advent of lower speeds and the use of safety belts, only runs l.4 and our general aviation rate is l0 times that. Also included in Table l are three specific small aircraft models on which we have good statistics. The Cessna Skyhawks have run at a level of 7 fatalities per l00 million passenger miles, and they are clearly the most forgiving and easiest to fly of the small single- engine aircraft. They still have a rate of 7, mostly because they are used a lot in training. In the 42ls, there is considerable professional pilot operation and the rate is down to 2. In the case of the Citations, where virtually all the piloting is professional, we are down to a rate of 0.4, which is the same as the airline rate of l0 years ago. I cannot put too much emphasis on this question of pilot 93
proficiency. Figure 5 also indicates the importance of that proficiency. Here, we consider Cessna fleet experience over a l0-year period. The reason I show this Is because it tells the impact of the biennial review instituted by the FAA. You will notice that fatalities increased as the fleet increased in size. The moment that the biennial review was instituted the fatalities dropped essentially in half. We must reduce the requirements for piloting expertise. Our airplanes, in the future, must be more forgiving, easier to fly, and better capable of coping with the environment so that proficiency is easier to achieve and maintain. It is important to recognize the safety areas in most need of attention. Accident statistics show that approximately one-half of all fatalities occur during approach and landing; another 20 percent are associated with takeoff. So, essentially 70 percent occur during takeoff or landing and are related to stall speed. Consequently, we need to do everything possible to reduce stall speed. We also need to eliminate the stall-spin accidents by making the airplane stallproof. It is also important to offer better ability for coping with the weather at a much lower cost, since about 20 percent of our accidents are weather related. Pressurization, anti-icing systems, weather radar, and radar altimeters that can be afforded in all airplanes are essential. In addition to the safety picture, there is also a big need for increased equipment reliability and a large reduction in maintenance requirements. Future customers will also insist on significantly improved comfort, primarily related to reduced noise and vibration levels. In addition, the requirement for good air-conditioning is going to exist in just about every airplane. The overriding need for the future, however, will be improved fuel efficiency. With the anticipated higher prices, fuel costs will certainly dominate the cost of operation of all our aircraft. Current fuel consumption status is illustrated in Table 2, in which statute miles per gallon (mpg) for an airplane and seat miles per gallon are presented. The numbers are good compared to the current American car and the current American airliner, which typically is a 50-seat-mile-per gallon airplane. However, they do not fare too well against the future 767s or 757s. We need to improve these numbers dramatically, and I think that with the technology promised it can be done. There is a very great promise in this potential technology, most of which has already been identified by NASA. With this technology I think we have the makings for dramatically improving performance, fuel efficiency, and safety. Realizing that potential will depend on a greatly expanded NASA effort in general aviation. Going back to the economic number I commented on earlier, we in the general aviation industry feel we have a stature today that says we have been seriously neglected in the share of NASA research. The biggest single potential improvement that is offered by the new technology is in the field of composite materials (see Table 3). Most of you are familiar with the numbers, but here they are for 94
Kevlar and graphite. Both of these fibers, as you know, offer strength-weight ratios that are superior to aluminum. NASA's ACEE program has done an outstanding job of proving the suitability of graphite for use in airliners. However, before the potential is realized for general aviation a lot of developments are needed, including better approaches to lightning protection, new inspection and testing techniques, interfacing with metals, new approaches to structural analysis and design, new matrix materials (which is a particularly important area), new manufacturing techniques, and new methods for field repair. In addition, the material cost must be drastically reduced. However, if it is pursued properly, by the l990s the problems can all be solved and the materials could be standard production items. The fact that Kevlar, the aramid fiber, is replacing steel in premium tires today on a economically practical basisâit is essentially dollar for dollar right nowâmeans that the potential for high volume, low-cost production of that material is promising. Consequently, we would expect it to become the general aviation structural material of the future. These fibers, principally Kevlar with some graphite used, offer a real potential for reducing the weight of newly designed general aviation aircraft by 35 percent. There should also be significant improvement in aerodynamic effi- ciency as a result of the universal application of refined versions of the NASA supercritical airfoil and the natural laminar flow airfoils. Dramatic advances in electronic technology will continue in the future, thereby decreasing the size, weight, and cost of all avionics, as well as increasing capability and reliability. We fully expect this to come from the avionics industry. It is moving well today and we expect to see it continue. Aircraft piston engines could be significantly better both in power-weight ratios and specific fuel consumption. Composite materials should be used extensively for weight reduction. Lean burning techniques with fuel injection and other improvements should also offer l0 to l5 percent reductions in specific fuel consumption. Even diesels could become usable with a 25 percent improvement in specific fuel consumption (SFC). Much more efficient turbochargers could contribute to improved SFC and power-weight ratios and will probably be used universally. These are areas where NASA has started programs, all of which are very promising. The biggest question is whether these programs will continue to be implemented properly. Turbo machinery should also be improved. Pressure ratios and compressor efficiencies have been limited in the small engines in the past because the sizes were too small to make use of highly efficient, axial flow compressors. However, today we see the way for development of centrifugal compressors that can be just about as efficient as the axials. This will permit the use of much higher pressure ratios and give greatly improved thermodynamic efficiencies. At the same time higher turbine inlet temperatures will be realized through such devel- 95
opments as nonocrystalline metals and ceramics for turbine blades and stators. Here again, composite materials will be used to reduce weights. Power-to-weight ratios could be increased by a factor of two. Specific fuel consumption should be improved by 25 percsnt in high-altitule operation. Here again NASA has made the start in these fields. The question is whether it will be followed up to achieve the potential result. The use of pusher propellers should be made practical for the future as a result of using composites for lightweight blades plus helicopter technology providing the lightweight, reliable drive shafts and gear boxes. This approach offers significant drag reduction, because there is no propeller slipstream impinging either on the fuselage or on the cells. In fact, there is no need for nacelles to produce drag at all. This arrangement also provides reduced cabin noise and better visibility. If developed on a timely basis these new technologies will generate many new airplanes that we expect will have the following common features and characteristics. All would be pressurized to provide the ability to fly over the weather and out of turbulence, with much greater efficiency and safety. All wings would have high aspect ratios of 9 or more. This would result in better climb, lower stall speeds, and better L/D ratios at high altitude. All would have full-span flaps with slot-lipped roll spoilers and flight path spoilers. The latter would be controlled by the throttle to provide negative thrust. All would have angle of attack sensors, limiting elevator power to keep the aircraft from stalling. This feature, combined with flight path spoilers, should completely eliminate the stall-spin accident. All would have advanced automatic flight control systems, the heart of which would be a central computer receiving information on all aircraft functions, including an air lata system made possible by low-cost sensors. All the navigation functions would be integrated with this, including DME (distance measuring equipment) and RNAV (radio navigation). The system would automatically calculate and fly optimum flight profiles. It would also eliminate the possibilities of disorientation and spiral dives- In many of the aircraft the system would be sufficiently redundant to offer automatic blind-landing capability at airports equipped with the necessary microwave systems. Most would have engine monitoring systems sensing vibrations, torsional loading, and metal in the oil to anticipate engine failures well in advance. This would increase safety, reduce engine maintenance costs, and make the fuel-efficient single-engine aircraft very safe. The six-place and larger airplanes would have strain gauge systems mounted on the landing gear that would provide an automatic weight and balance readout from the computer. All the airplanes would have radar altimeters, and most would have other radar. Most would have all-weather systems, including an anti-icing capability. Inspection periods would increase from l00 to 300 hours or once a year. Now, I would like to examine a few examples of the aircraft that 96
these new technologies should make possible for the l990s. The minimum four-place aircraft is depicted in Figure 6. It is essentially a very streamlined Skyhawk; however, it is supercharged and is pressurized to a 2.5 psi differential for cruising at l6,000 feet, which is above the worst weather problems, but still low enough to eliminate any concern over catastrophic decompressions. It also minimizes the weight penalty. We would expect this new aircraft to be 25 percent lighter in empty weight than today's Skyhawk. The supercritical airfoil and the full-span flaps would combine to make reduction of the wing area by over one-third possible. However, the wing span has been retained in order to give good climb characteristics and a high L/D. The high-aspect ratio wing has a composite support strut with less than half the drag of today's struts. This future Skyhawk would cruise at 185 miles per hour and offer a range of 900 miles under visual flight rulas. At the same time it would cost less to buy, operate, and maintain (in constant dollars) than the Skyhawk of today. Figure 7 exemplifies what could be a turbocharged liesel-powered four-place airplane. Because the engine is relatively heavy it is located in the nose with the propeller mounted on the tail. This provides an efficient aerodynamic configuration as well as a vary low cabin sound level. The cabin would be pressurized to 4 psi, giving a 25,000-foot cruise altitude. The diesel would run at 3500 rpm with a light-weight drive shaft transmitting the power to a gear box at the raar, where the rpm of the prop would be cut to 2000. The drive shaft would pass through a center-tunnel armrest, as in a sports car. Wide chord composite propellar blades would provide good efficiencies at a high-altitude cruise. Because of these capabilities, this airplane should cruise at 250 mph, have a l600-mile range, and offer 26 mpgâa raally high level of fuel efficiency, better than l00 seat miles to the gallon. A minimum-cost twin-engine aircraft is shown in Figure 8. To provide a minimum cost, we have used two supercharged automotive Wankel engines. Their compact size and light weight make possible the convenient arrangemant for the safety of center-line thrust. Since these engines are liquid cooled, the radiators would be the aluminum leading edges on the wing and on the tail surfaces. This would provide an automatic anti-icing capability. This would also be a 250-mph airplane cruising at 25,000 feet, but would only get about l8 mpg. Although the Wankel engine will always be inferior to the piston engine in SFC, its lightweight, compact size, and lack of vibration will perpetuate its development as an automotive angine with the result that its low cost could make it very attractive for personal aircraft. The lack of a valve train and its basic simplicity should also make Lt very reliable. Another new type of aircraft that we expect to be very popular in the 1990s is a single-engine turbopropeller type in a pusher configuration. This would be a six-place airplane, pressurized to 8 psi with a 400-mph cruise spead, and the ability to fly at altitudas 97
up to 40,000 feet. We would be looking at a turbo-shaft engine with 6000-rpm output reduced to l800 for the propeller. The rear-mount engine and propeller will provide a very quite, smooth, cabin environment. It would have an l800-mile range capability. Because of the engine monitoring system it should be possible to virtually eliminate any concern over engine failure. This would offer a l6-mpg capability, again approximately l00 saat miles per gallon. This type of airplane will replace many of today's piston twins. Another new category of aircraft for the future would be the twin-turbine single-propeller airplane shown in Figure 9. The two turbine engines, which have their inlets in the wing roots, would be geared together to drive the single propeller. In this way, you not only have two engines but also the safety of center-line thrust. Some people may object to the single propeller; however, people flying today in twin-engine helicopters depend on a single rotor to stay in the sky. This propeller would have a very high activity factor to drive the airplane at 450 mph at 45,000 feet, making it very comfortable and providing a cross-country nonstop range. It would have 8 to l0 seats and offer a fuel efficiency of better than l0 mpg; again, approximately l00 seat miles to the gallon. Continuing on up the scale in speed in the l990s, we should see a Mach 0.95 business jet, which is illustrated in Figure l0. This would offer a 20 percent increase in speed over today's business jets and, at the same time, provide high fuel efficiency. It would be necessary to bury the engines, "area rule" the fuselage, and go to highly swept wings with supercritical airfoils. We would also be looking at canards. The winglets in this case would serve the dual purpose of increasing aspect ratio and directional stabilizaion. You can see in this many NASA outputs, and we would expect to use even more. This airplane would offer stand-up aisle height, l6 places, plus a 600-mph cruising speed at altitudes up to 60,000 feet, with ocean-crossing range. Even with this speed it should offer a fuel efficiency of better than 4 mpg. It also offers the safety advantage of essentially having center-line thrust and would have a cabin that is free of engine noise. Another important future category for general aviation will be short-haul commuter transport. This market will grow in size by many times in the next l5 to 20 years. Consequently, new designs will be developed in which the principal emphasis will be on the minimum amount of aircraft weight per passenger lifted into the air. One approach to such a 50-passenger machine is illustrated in Figure ll. By using a tandem wing configuration, minimum drag is achieved with good control power. This also makes possible an aft location of the turboprops to provide minimum cabin noise. It would be pressurized to cruise at 25,000 feet, where it would achieve speeds up to 300 miles an hour. Even for l00- to 200-mile routes it would offer over l00 seat miles per gallon. In summary, in the l990s the potential exists for general aviation aircraft to generally provide 25 percent more speed with 50 to l00 percent better fuel efficiency plus greatly improve! safety, reliability, convenience, and comfort. The accident rate would be 98
reduced by well over an order of magnitude and it would be safer than cars. This should all come about if the new technology is developed on a timely basis, which will require substantial effort by NASA. In this way we would stay ahead of our foreign competitors and substantially increase the growth rate of general aviation. A major concern today is the fact that there are l0 other countries already engaged in general aviation production and several others in the process of developing a general aviation industry. All of these governments are strongly supporting their industry by subsidizing R&D and tooling from 80 to l00 percent and, in many cases, subsidizing the manufacturing costs. On top of that they heavily subsidize marketing with low-interest, no-down-payment financing. Put together, this is a very serious threat, which in a five-year period could easily take the general aviation market away from the United States. A very important aspect of the export market is the fact that in developing nations, where there are no railway or highway networks, general aviation aircraft can provide instant transportation systems with a very small capital investment. This creates a particularly good potential for rapid growth in this export market. In closing, I would just like to make one comment on the importance of U.S. preeminence in aviation. Many, if not most, people throughout the world regard flying as man's most magnificent achieve- ment. I think that is really true. It is not just this group here; I think it is true of people in general. This is borne out by the fact that most developing nations' first objectives after they develop any kind of economic stature is to have a national airline and then to have an air force. Not far beyond that comes having an aircraft industry. In addition to the great economic importance that general aviation leadership offers, the continued position of preeminence in aviation manufacturing, we think, is the most important means for the U.S. to maintain its role of world leadership. Without preeminence in avia- tion, I think we can all be assured that we are going to be regarded as a second-rate nation throughout the world. Thank you. 99
MILLIONS OF > 2R500 2R250 2S000 1R760 GENERAL AVIATION SALES 1970 1971 1972 1973 1974 1976 1976 1977 1978 1979 PERCENT GENERAL AVIATION SALES TO MILITARY SALES 50% 40% 30% 20% 10% 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 l00
PERCENT GENERAL AVIATION SALES TO HELICOPTER SALES 700% 600% 500% 200% 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 PERCENT A GENERAL AVIATION SALES TO TRANSPORT SALES 60% 40% 36% 30% 26% 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 l0l
TABLE l Fatality Rates per Hundred Million Passenger Miles Airliner Overall general aviation Passenger cars Passenger cars on turnpikes Skyhawks 42ls Citations 0.04 l6.0 l.4 0.7 7.0 l.5 0.4 1ST BIENNIAL REQUIRED BY 11/74 440 400 360 320 280 240 200 160 120 80 40 Eâ â- 7 â__ \ ^- T Aâ = / \ FATALITIES^ \ â " \ . â ^, ⢠^ ' . ^ SI _ â -* FATAL _ â â - â â . ACCIDENTS^ 1970 71 72 (46 6OO AIRCRAFT! 73 74 75 76 77 78 181.100 AIRCRAFT) ANNUAL ACCIDENT RECORD - CESSNA DOMESTIC FLEET FIGURE 5 l02
TABLE 2 General Aviation Fuel Efficiency MPG (Statute) Seat Miles Per Gallon Skyhawk Pressurized 2l0 42l Conquest Citation II l7 l2 7 5.5 3.5 68 72 49 55 30 COMPOSITE CHARACTERISTICS TENSILE COMPRESSIVE DENSITY MATERIAL STRENGTH MODULUS STRENGTH MODULUS #/CUR INR io3 PSI 106PSI io3 PSI io6 PSI KEVLAR 49 GRAPHITE ALUMINUM 200 110 60 11 40 100 36 10.5 28.0 10.5 .05 .06 .10 2024 T3 28 10.5 (YIELD) (UNIDIRECTIONAL FIBERS IN EPOXY LOADED IN DIRECTION OF FIBERS) TABLE 3 l03
FIGURE 6 An Example of a Minimum 4-Place Aircraft of the Future FIGURE 7 An Example of a Turbo-Charged Diesel-Powered 4-Place Aircraft FIGURE 8 An Example of a Minimum-Cost Twin Engine Aircraft l04
FIGURE 9 An Example of a Twin-Turbine Single-Propeller Aircraft FIGURE l0 A Mach 0.95 Business Jet of the l990s FIGURE ll An Example of a Future 50-Passenger Short-Haul Commuter Aircraft l05
