THE TURBINE - An Alternative to the conventioal engine

Accordint to the U.S. Government's Advisory Committee on Advanced Automotive Power Systems, among all the known alternatives to the piston internal-combustion engine the gas turbine has the greatest potential for replacing that beleaguered machine in the 1970s. If the gas turbine has the greatest potential, I shudder to think of the problems facing those power plants with less potential steam, electric, the Stirling engine and various hybrids - - for it's going to take several minor miracles to make the gas turbine into a practical proposition for cars. On the other hand, it's easy to see why the government committee gives it the best chance; it has compelling qualities.

The gas turbine swept the field of commercial aircraft many years ago, making piston engines a thing of the past for all aircraft but small private ones. For a brief transition period, gas turbines-that is, turbines with an output shaft driving a propeller-powered the fastest commercial planes and readers will recall the Lockheed Electra and perhaps the British Vickers Viscount. After that another form of the gas turbine-the "pure jet" which dispenses with the output shaft and simply exits the burned gases for thrust took over and revolutionized commercial aviation. Meanwhile, shaft gas turbines still power many short-range, smaller planes such as the Fokker-Fairchild F27 and the commuter De Havilland Twin Otter.

For aircraft the gas turbine is a natural, because (at least in its basic form) it is fundamentally a constant-speed unit. It operates efficiently at or near its maximum speed and load, very inefficiently at low speeds and loads. Its combustion area and turbine wheels are subjected to sustained high temperatures and these are tough enough on materials without the added complication of temperature cycles caused by stop-and-go and change-speed operation that goes with automobiles.

It's not, however, as if nothing had been done toward making the turbine an automotive engine, and the pioneering work of Rover and Chrysler, plus the less well known work of Ford, General Motors. Volvo and British Leyland, have produced some very significant progress toward that end.

Chrysler went the furthest, but after the highly publicized 1963-64 project of building 50 turbine cars and loaning them to American drivers for "owner testing," Chrysler quietly let the automotive gas turbine fade into corporate darkness.

Things have changed since 1964. The factors that justified putting the turbine to pasture then (high cost of materials. the need for development work to correct its inherent deficiencies for use in cars) have become less significant in comparison to the turbine's potential for reducing air pollution. That potential is great, as we shall see: and the most compelling attraction of it (in contrast to a "controlled" piston or Wankel Internal- combustion engine) is that it is fundamentally a low-emission power source, not a high emission one that must he loaded and strangled with 'crutches."

How It Works

Gas Turbine operation, in principal, is simplicity itself, and one might say that the variation among various types of turbines is less than that which we find in piston engines. Fig. I illustrates the operation of the simplest imaginable sort of gas turbine, a Boeing 502, with a single compressor stage and no regeneration (about which more later). Air enters the compressor, here a centrifugal one, and is of course compressed. It is then delivered to the combustion chamber under Pressure, and here the fuel is introduced, mixed with the air and burned, the quantity injected determining speed and power output. the hot, high-pressure burning gases then proceed to the first turbine, which drives the compressor, and continue to the power turbine, which delivers power to the output shaft through reduction gears. The gears are necessary because the speed of turbine rotation is measured in tens of thousands of rpm, not thousands: a typical power turbine speed is 45,000 rpm.

The power turbine illustrated in Fig. 1 is free turbine. By free we mean that it is not mechanically connected to the rest of the gas turbine motion; it can he brought to a standstill while the compressor turbine is rotating at its idling speed of, say, 20,000 rpm, just as the output turbine of a torque converter can be brought to a halt while the input turbine (impeller) rotates with the engine at idle speed. Thus a gas turbine engine with a free power turbine is in effect its own torque converter and requires no clutch, fluid coupling or converter between it and the transmission.

There are pros and cons as to whether the power turbine should be free or not. Fig. 2 is a schematic of an automotive turbine, built by Williams Research Corp., whose power turbine is shafted to the compressor turbine. Obviously this sort of engine is going to require some kind of clutch or coupling to disconnect it from the drive wheels when the car is stopped. But there's an advantage here in that engine braking-of the sort we expect from piston engines-is available when the driver lifts his accelerator foot. With a free turbine there is near, no braking unless special provisions have been made for it. One solution to the lack of braking is to connect the power turbine shaft of a free-turbine engine to the compressor shaft via a one-way or overrunning clutch, so that only when that shaft speed tends to exceed compressor speed is there a coupling. However, there are problems that crop up when fitting such a clutch into the high-temperature environment.

Chrysler took another approach to providing engine-braking beginning with their third series of turbine engines: a variable- pitch turbine stator-vane mechanism. Fig. 3 is a cutaway drawing of the 1963 Chrysler turbine: component D is the ring of stator vanes that direct gas flow from the first (compressor) to the second (power) turbine. The mechanism is capable of selecting three different angles for the vanes: for braking the gas flow is actually directed contrary to turbine rotation for braking effect. There are new problems with this feature-again that of a mechanism operating in an extremely hot place, and some additional gas leakage due to the clearances required for the mechanism to operate but the variable-pitch idea is certainly a reasonable approach to solving the lack of braking with a free power turbine, and Ford chose it for their Upcoming production truck gas turbines.

Regeneration & Recuperation

A s I Mentioned earlier, a gas turbine operates quite efficiently at high speeds and loads, consuming about 0.5 lb fuel per horsepower-hour at cruising speeds. This is comparable to the economy of a piston engine in a car at highway speeds. At idle, or at relatively low speeds and/or loads, it is nowhere near as economical (on a similar basis of fuel consumed per unit work delivered) as old friend piston engine.

Now, since aircraft engines or stationary power sources operate mainly at constant speeds, these turbines are designed to run in their most economical range at the planned speeds and they can be designed without any means of recuperation from exhaust heat. For an automotive turbine engine, which will be required to stop and start frequently and change speed frequently even on the highway, sonic means has to be found to raise its economy under low-load and low speed conditions. Recuperation or regeneration is the means. Recuperation uses some sort of stationary heat exchanger to deliver exhaust heat to the intake air: regeneration uses moving (generally rotating) heat exchangers. Regeneration is considered to be the more effective way of accomplishing this and seems to have been adopted universally for automotive applications in recent years.

Refer again to Fig. 2, the Williams turbine, an 80-bhp unit that will be installed in an American Motors Hornet for testing in New York City. Here we have what is now a common configuration of regenerator: two large discs of Cercor, a ceramic-glass material developed by Corning Glass Works for the purpose, rotating at a speed determined by gearing from the compressor shaft. In the case of the Chrysler turbine of Fig. 3, which has the same type regenerator discs, the gearing is on the order of 2100:1 so that a maximum compressor speed the regenerator is doing only 22 rpm! Fig. 4 is a photograph of a regenerator rotor, and the right portion shows the porosity of Cercor under magnification. Porosity aids the heat transfer.

Other Variations

The Compressors of all the gas turbines shown so far are radial or centrifugal: that is, the incoming air is flung outward from the centerline of the compressor for its compression. We can have axial compressors too, in which the path of the air being compressed is parallel to the shaft. And one compressor is not the limit by any means: there can be several stages, depending upon the power output desired and the complexity allowed by cost limits. The Pratt & Whitney ST6 unit, as used in the original STP turbine car that almost won Indianapolis, has a 4-stage compressor with three axial and one radial stages. Another form of compressor, relatively rare, is the centripetal: this is shown in Fig. 5, a cutaway of a new turbine being developed by a company called Turbotron. Many other variations in configuration are possible; the first regenerative Chrysler turbine had a single, extremely thick disc atop the engine instead of two at the sides, for instance.

The Turbine's Attractions

The Greatest attraction of the gas turbine, and that from which all its peripheral attractions derive, is its utter simplicity and directness in getting power from burning gas. Consider, for contrast, the internal-combustion piston engine: pistons stopping and starting, spark plugs firing, valves opening and closing, camshafts camming, breaker points breaking, connecting rods rocking back and forth on piston pins, perhaps even fuel injection squirting intermittently. It's the eighth wonder of the world that all this can go on 60-70 times per second in your personal car as you cruise on the freeway without disturbing your listening to the stereo. But it does, and that's testimony to the efficacy of year-in year-out development of the details.

But in the gas turbine the motion is simple and continuous. All the parts that are in regular motion are rotating. So the potential smoothness is obvious, and in practice it is there. The turbine is quiet too, assuming full silencing of intake and exhaust: its most characteristic sound is the high-pitched whine of those turbines whirring at 5-digit speeds.

The simplicity of the turbine enables it to be light and compact in its pure form; hut for an automobile the necessity of regenerators downgrades these advantages. Still, putting the turbine in its most favorable light (comparing a truck turbine to the big diesel it replaces) for comparable power it comes out 50% lighter and about 30% smaller, and this is with regeneration. These figures are for the heavy truck units Ford Motor expects to have in production by August of this year: they are in the 335- to 450-bhp range. Also, in a truck the turbine's quietness and smoothness advantages really mean something: compared to a big diesel the difference is startling.

Lubrication requirements for it ails turbine are minimal. There are a few relatively lightly loaded hearings dealing only with rotary motion. There is no blow-by of combusted gases into the oil supply. So there is practically no oil consumption and it could be that no oil changes would be required. For turbine-powered aircraft the oil is usually changed every 3000 hours or so: for a car this would be about 100,000 miles. There is no need for water-cooling: all turbines are air-cooled, and at that no external cooling blower is required.

Cold starting is another credit for the turbine. The resistance of' a gas turbine to spinning up to starting speed does not change much with cold ambient temperature. In contrast, reciprocating engines have everything stacked against them for cold starting with so many oil-lubricated surfaces to get rotating and sliding against each other. Again, the greatest advantage of the turbine here is in contrast to the diesel, which depends heavily upon cranking speed to get up combustion temperature. Gas turbine proponents say that the cold starting advantage (even in contrast with car spark-ignition engines) could alone mean a substantial reduction in urban air pollution on extremely cold days by eliminating aborted starts. And turbines need no cold mixture enrichment!

Multi-fuel capability is another turbine calling card. A gas turbine will run on almost any hydrocarbon fuel: kerosene, diesel fuel, furnace oil, LNG, LPG, your 151-proof rum, etc. This could be an advantage as world supplies of petroleum diminish and deprive us of the privilege of being so selective about which fuel we use.

But it's the turbine's emission characteristics that have revived interest in it for automobiles. It is, in comparison to the piston or Wankel IC engines, an inherently clean-burning power unit. Its combustion is continuous, not explosive: it takes place at such a high temperature that-at least under its most favorable operating conditions-unburned hydrocarbons (HC) and carbon monoxide (CO) concentrations in the exhaust are practically negligible. For the various oxides of nitrogen (NOx), it's a slightly different story as the very high temperatures that promote "clean" combustion also cause these nitrogen oxides as byproducts of combustion. Mind you, NOx, formation is not an evidence of incomplete combustion, but rather a side effect of even perfect combustion at temperatures of 2900°F and over. This temperature level is reached intermittently in it piston engine, continuously in a turbine. Compare the performance of three turbine cars to the newly enacted federal emission limits for 1975 and 1976 new cars and current limits for new cars:

*1 Korth & Rose, S.A.E. Paper 680402. Society of Aulomotive Engineers, New York. 1968

*2 Noel Penny, in Science Journal, April 1970

*3 Victor dc Biasi in Gas Turbine International. Jan.-Feb 1969)

As many of us driving a 1971 car know, those 1971 limits (the HC and CO limits must be met by any new car sold in the U.S.) already entail a considerable loss in the general satisfactory operation of a piston engine: sacrifices in cold starting and warm-up performance, general tractability, quality of idle, fuel economy and Power output are almost taken for granted in meeting current standards. Furthermore. for a current engine to continue to meet these standards-which obviously are duck soup compared to the upcoming ones-it has to be kept adjusted finely, and it's simply not the nature of the piston engine to stay adjusted that precisely. And since the correct adjustments for low emissions produce those poor running symptom,, you will find owners and mechanics tampering with the adjustments to get better running. It's happening everywhere, laws or no laws. Finally, mechanical deterioration degrades the emission performance of a piston engine. In all, things look quite hopeless for our current style of engine, despite the hopeful statements from industry engineers that they are now getting "very close" to the 1975-1976 limits with highly modified piston engines.

But look at the turbine performance listed above. Two of the three get close enough to the HC and CO limits that they can he considered "home free--and this is how the turbines performed in relatively natural form. Only on the NOx is there a pessimistic note, and General Motors engineers reported recently that they have been successful in reducing nitrogen oxide formation by 35-55% in their GT-309 truck turbine engine by shortening the combustion region in the burner and altering combustion-chamber airflow. They project that these same changes would give a 40% reduction in NOx from current technology in passenger-car turbines., but caution that a lot of work lies ahead to go the rest of the way.

I mentioned the intimate relation of tuning, maintenance and mechanical deterioration to pollutant emissions in the piston IC engine. Here the turbine scores again. There is no such thing as a tune-up for a gas turbine. No timing to adjust, no spark plugs to replace (a single sparkplug-like device is used to get combustion during starting, but it is self sustaining once started), certainly no carburetor to adjust, and what fuel injection there is is simple compared to that used now. As for mechanical wear, it does not affect turbine emissions in any significant way as the combustion process is not affected by bearing or turbine wear. Deterioration in the accuracy of the fuel delivery system and high-temperature erosion of the combustion chamber seem to me to be the only sources of emission deterioration, and these cannot be as significant as valve, piston-ring and cylinder, carburetor or mechanical fuel-injection wear in a piston engine.

A final advantage of the turbine is its torque and power characteristics. Fig. 6 contrasts the torque and power curves of piston and turbine engines of similar output: 170-bhp (DIN) BMW 2800 engine and the engine of the 1963 Chrysler turbine car. But look: the turbine produces only 130 maximum net horsepower, vs. the BMW's net 170. How can they be "of similar Output"? Simply because the 13U-bhp turbine will produce comparable performance to the 170 bhp piston engine-in all respects hut top speed.

The solid line in the turbine torque curve is the ideal maximum torque and reaches an impressive 425 lb-ft at zero output speed. However, the only way to get this is to rev the compressor to full speed and hold the power turbine with the brakes, so the dotted line is closer to what we can expect in actual operation. By contrast the piston engine has to gather quite some speed-in this case 3700-rpm for its peak torque.

This has two implications. First, the turbine requires less in the way of a transmission than the piston engine. With the latter, in a 3000-16 car, a 4-speed manual or a 3-speed automatic with torque converter is fitted. Let's take the automatic for illustration. It has a 1st gear of 2.5:1 and the converter multiplies torque by 2.0:1 at stall, giving a 5.0:1 overall torque ratio available at a standstill. Thus the BMW, if its engine can rev to 2500 rpm on moving off from rest, would have 163 x 5.0 = 813 lb-ft torque at the drive shaft for acceleration. The other two gearbox ratios, 1.5:1 and 1.0:1, and the steadily decreasing torque multiplication of the converter provide a fairly smooth and, like the turbine, decreasing curve of torque available as car speed increases.

Now for the turbine, we could plan for a torque of 350 lb-ft. To get 813 lb-ft torque at the drive shaft we would need only a 2.33:1 -ear ratio, and a 3-speed automatic gearbox without a converter would do nicely. The Chrysler turbine car, with this 130-bhp engine but weighing a hefty 4000 lb, got by with the automatic gearbox of a Chrysler torqueflite transmission and no converter.

In designing cars with good acceleration for traffic, we've had to equip them with piston engines of far more power output than required for an adequate top speed. After all, it's maximum power, not torque, that determines the top speed of a given car and if the BMW can use the 126-mph top speed imparted by its 170 bhp on a German autobahn, the typical American sedan with similar power cannot use that speed in typical American driving with speed limits. The 130-bhp turbine would, as I said, provide similar acceleration in the usual driving speed ranges but would have a top speed of only about 110 mph. With the possibility of a government-imposed maximum speed capability of 95 mph-which R&T unalterably opposes but which could be enacted-the turbine could be designed for that top speed and still have adequate acceleration, whereas the piston engine might wind up still over designed for top speed and artificially governed.

The Other Side

That’s A list of plusses long enough to make us want to rush right over to Detroit, Stuttgart, Coventry and Tokyo and demand a turbine engine in our 1971 cars. But the list of failings is just as long and raises serious doubts as to whether the gas turbine is our engine of the future.

First and best known are matters of cost. Any gas turbine so far developed requires a fair quantity of very expensive metal-mostly nickel and cobalt-in the areas of high temperature, such as turbine blades. Williams Research estimates 11 lb of these materials in each of its 80-bhp units and adds that the cost of processing the metals is a greater factor than that of the raw materials. Chrysler's gas turbine department says that 7 lb of the eleven are nickel-based alloys and estimates that we would be using 15-16% of the free world's annual nickel if we produced 10 million of the turbines per year-and that's a big chunk of the metal.

Aside from the materials, production costs are high for turbines despite the simplicity and lightweight. Extreme accuracy is required in the assembly and production of rotors that are going to be turning 45,000 rpm. The potential smoothness of a gas turbine can be ruined by tiny inaccuracies in a rotor, and such an inaccuracy can lead to a centrifugal blowup of the engine-a dangerous as "ell as uneconomic happening. Piston engines are also required to conform to very close tolerances, but in their production, parts are sorted for size rather than the off-size ones being thrown away: for instance, connecting-rod bearings that turn out oversize are fitted to crankshaft journals that are oversize. Perhaps this technique can he applied in automotive turbine production.

The high temperatures prevailing, besides promoting formation of NOx, increase heat insulation requirements in the car. Noise insulation, on the other hand, might he somewhat less critical but total passenger-compartment isolation from noise and heat probably must be at least as heavy and costly as in current piston-engine cars.

I mentioned earlier that a gas turbine is essentially a constant-speed unit that is happiest and most efficient when it's running at full speed and load. I also mentioned some of the work that has been done on it to make it conform better to our seasoned automotive requirements of start stop, speed-up, slowdown driving, such as the variable pitch power turbine vanes. Another aspect of the turbine's constant-speed nature is that it is slow to respond to an operator's demand for a change of speed: this is the well known "turbine lag," and again in airplanes (or to a lesser extent, trucks primarily for Interstate highways) this is not important. But in a car it is-at least we've come to expect the instant response of the piston engine to a push on the accelerator. In Chrysler's first turbine engine it took a full 7 seconds after the go-pedal was depressed for the engine to develop its full torque output! But steady development, and particularly the addition of the variable vanes, has brought this down to less than 1.5 sec and perhaps drivers could adapt their driving habits to compensate for this lag.

One solution to this response problem, by the way, is simply to keep the compressor turbine going full bore when the "throttle" is closed and dump the excess gas out the hack door. The Howmet racing car, whose engine is shown in Fig. 7, had this provision, called a "waste gate." Not exactly a practical proposition for a road car, however.

The advantage of mechanical quietness is pretty academic these days, as anyone who has driven a large American sedan with its ghostly quiet V-8 engine can confirm. The same for mechanical smoothness. Nice features on paper, but today they mean little.

By now some readers must be wondering about all that black smoke they've seen from jet and turbine aircraft as they take off. It's a bit like truck diesels-they're cleaner burning than spark-ignition engines too, but they give off more smoke. Smoke, the visible stuff, is what the emission experts now call particulate matter, tiny chunks of residue coming out of exhaust pipes, as opposed to gases. Particulates drift to the ground and they're not really a part of the photochemical smog problem, but New York residents can testify to the effects of large amounts of particulates and the federal government intends to put limits on these too. The smoke one sees from some turbine engines is the result of an over-delivery of fuel to the combustion chamber and some jets, notably the Pratt & Whitney JT3 used in smaller jet airliners, are notoriously capable of this condition. A turbine expert I know had a talk with one of the test-users of a Chrysler turbine car in 1964 in a hotel parking lot, after which said test-user put the car in gear and his accelerator foot to the floor. The parking lot was quickly polluted with black smoke and the driver was embarrassed. Same thing: oversupply of fuel, more fuel than could be burned. Electronic controls will be necessary to prevent this condition-controls that are somewhat analogous to today's electronic fuel injection for IC engines.

How well established is the turbine's durability in automotive, as opposed to constant-speed, operation? I don't know. One turbine authority said in 1963 that 1500 hours (or about 50,000 miles) is the state of the art. Of their truck turbine the Ford people say "better than the diesel" and that means better than 500,000 miles to the first major overhaul; but how that will extend to the automotive regime I can't say.

Another fact about the gas turbine that could he a problem at times is that its output is affected sharply by ambient temperature. For instance, the manufacturer of the 1967 STP-Paxton Indianapolis turbine car engine (Pratt & Whitney) guaranteed 540 bhp (a 6230 rpm-at 59°F and sea level. But if the ambient temperature goes up to 80°F, that comes down to 470 bhp, and at I00°F it's only 400 bhp. Piston engines are affected by ambient temperature too, but the power drop with increasing temperature is nowhere near this great.

The gas turbine engine is, in the words of one turbine expert, an "outsized air compressor." It ingests a terrific amount of air compared to that the piston engine takes in, especially at idle; and handling all this air at idle takes a large amount of power. This is a prime reason for its poor economy when idling. Proponents of the turbine have noted, especially in connection with the air-intake restrictions that effectively took the turbine out of the running at Indianapolis a few years ago, that if one includes the cooling airflow of a conventional engine that is the air processed by the engine fan either over cooling fins or through a radiator, its air consumption is quite similar to that of a turbine of comparable output. They also claim that the excess air handled by the turbine is just that, excess and that it emerges from the engine as oxygen. One well-known turbine man, George Huebner of Chrysler, even says that the unburned hydrocarbons in polluted air ingested can be burned in the turbine! In any case, the old parts-per-million measurements of pollutant concentrations in the exhaust would he quite meaningless for a turbine, and the current methods of measuring ppm and converting to grams/mile must take into account the much greater exhaust volume of the turbine. The quantity of air ingested and exhausted by a turbine is nicely illustrated by Fig. 8.

A New Approach

I see that I devoted only about half as much space to the turbine's disadvantages as to its advantages. Perhaps that's a good omen for it. Another good omen seems to be a group of people in Irvine. California who call themselves Turobotron and who, under the leadership of the Czech engineer Vladimir Pavlecka, are developing a form of gas turbine that promises to overcome some of the drawbacks I've outlined.

The Turbotron concept is shown in Fig. 5. At the right end is the 3-stagecompressor, which is its first distinctive feature: this is a centripetal, rather than the usual centrifugal or axial compressor so that it sends its compressed air inward. This is then delivered to the second distinctive part of the Turbotron, its unusual combustion chamber. Shown schematically in Fig.9 along with a conventional chamber schematic for contrast, this is called a film evaporative combustion chamber. In the conventional chamber the fuel is delivered in a spray that atomizes it into tiny droplets; primary air enters along with the fuel (this can be seen less schematically in Fig. 1), and secondary air enters through holes in the combustion chamber wall. There arc two troubles with the conventional process, say the Turbotron people: first, that the fuel is only atomized, not vaporized; and second, that the secondary bleed holes are perpendicular to the secondary airflow and the main flow of gases through the chamber. The two resulting conditions are detonation-yes, that's the same thing that can cause "pinging" in your piston engine and who would have thought it happened in a turbine-and incomplete mixing of secondary air with the burning mixture.

Turbotron's solution is shown in the second half of Fig. 9. Here the primary air enters with great swirling motion imparted by the centripetal compressor into a chamber of increasing diameter. The fuel is introduced peripherally and, Turbotron claims, heated and vaporized by the hot, swirling air. Secondary air is brought in at the far end of the chamber, and the claim here is that the swirling motion induces much improved mixing here; it is in this area that most of the combustion takes place. Turbotron further explains the film-evaporative process by an analogy to the Bunsen burner flame (shown also in Fig. 9) in which there are two visible sections of the flame, the blue (secondary combustion) part at 1700°F and the orange (primary) part at 3600°F. Pavlecka says that most of the combustion in this chamber takes place at the blue, or lower-temperature, level-thus reducing the NO, formation.

The third trademark of the Turbotron aims at reducing maximum rotational speeds in the turbine, which Pavlecka says cuts not only the danger of centrifugal blowup but response lag. Turbotron's compressor is a 3-stage affair with the center one rotating in opposition to the first and third. This requires internal gearing, but the center stage rotating backward is like a stator with the other two stages rotating at more than double speed: Turbotron plans only 14-16,000 rpm for the actual maximum speed of the compressor turbines. The power turbines (five stages of them) also use this counter-rotation in two of the stages. There are other aspects of the Turbotron that promise advantages over current automotive turbine technology, but this summary will suffice, as all the claims are strictly paper claims now and no hardware is operating yet. The ideas are certainly intriguing.

The Status of Things Turbine

THE WINTER meeting of the American Society of Mechanical Engineers got together the heads of America's top gas turbine specialists to explore its future as an automotive engine: from Ford. GM, the University of California, the U.S. Air Pollution Control Administration, United Aircraft, John Deere and Lear (Bill himself). The man from United Aircraft (that's Pratt & Whitney) was understandably optimistic, declaring that a turbine without regeneration could be engineered to give 11 miles per gallon; the GM representative disagreed, saying 3-4 mpg was more like it for the sort of non-regenerative turbine the UA man was discussing. Ford's man indicated that the main activity at Ford just now is getting the truck turbines into production at their new plant in Toledo, Ohio, but development of car turbines continues. Lear's current activities are concentrating on a steam, not gas, turbine; but Lear suggested that he has come up with a fuel vaporizing device to replace the conventional atomizing fuel nozzles at the combustion chamber, which could do somewhat the same thing the Turbotron people are talking about.

Right now, if there's any new flurry of activity in gas turbines in the car making companies as a result of the new pollution regulations and HEW's interest in the turbine, it's difficult to find it. The grapevine says there is at GM, but they're not confirming it; Ford says it's trucks only. Chrysler has quietly continued to develop turbines since the 1963-64 project, is now on its sixth generation, and claims that much progress has been made in the last few years.

Will the Turbine Make It?

See your nearest crystal ball gazer. I've outlined the plusses and minuses, and that's about the best that can he done at the moment. The cost troubles could be softened by the fact that if the piston engine can be cleaned up which I doubt-the cost of it and all the add-on devices could be so high as to make the turbine far more competitive than it now appears. Too, the piston engine has already suffered in performance and economy in conforming to pollution regulations and likely will continue to, so that by 1975 not only would it he far more expensive than it is now but far less satisfactory in performance, tractability, smoothness and economy.

Speaking of cost, we have opined several times in R&T that sometime in the future the automobile is going to revert to its original status of a luxury. Henry Ford may have made history by mass producing cars and giving them to everyman, but it's all too obvious that when everyman has one (or, worse, two or three) there are far too many of them. Making the automobile conform to the environment, instead of vice versa as has been the pattern in America, inevitably is going to raise its cost-probably so drastically that a smaller proportion of the population will be able to afford it. This has been accomplished in European and Asian countries for many years by discriminatory taxation of automobiles and fuel. Good public transportation has been provided in the cities of these countries, and obviously with lower personal earnings and higher car and operating costs than in America, the citizens of these countries must use public transportation to a great degree. If the automobile does get this costly in America-and, as I said, I think it is inevitable-then we have to provide public transportation for those who can no longer afford a car. It's going to be a tough transition, to put it mildly.

The gas turbine automobile could be the car, and the luxury, of the future.