Monday, September 25, 2023
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jet_fighter5.jpg
27 Sep 2022
The GM Firebird is the land-based incarnation of the jet-powered Douglas F4D Skyray.

The GM Firebird is the land-based incarnation of the jet-powered Douglas F4D Skyray.
Usually, the convergence of the worlds of cars and airplanes happens at the level of allegories, but seventy years ago, Americans almost managed to do it literally. It is symbolic that the era of the “Detroit Baroque” was standing in the yard - magnificent design in an aviation style. Huge imposing V8 barges of immodest displacement boasted tons of chrome decor and tail fins a la fighter jet plumage. Against the background of this vanity fair, the revolutionary project of General Motors looked like a marvel of technology stuck between earth and sky.

Actually, the name Firebird is not associated with aeronautics. It belonged to four generations of the once-famous Pontiac ponycar, the closest relative of the Chevrolet Camaro. The experimental and now forgotten namesake had appeared thirteen years earlier and would surely have delighted Jules Verne himself. It is symbolic that it was created by Jim's artist Harley Jarvis Earl, a romantic and dreamer with an individual vision of beauty.

In his younger years, a native of Hollywood could become a movie star and play the role of some kind of mafia type or politician - with his outrageous appearance, this would not be difficult. But Earl chose the family business and followed in the footsteps of his father, who first worked in the manufacture of horse-drawn carriages, and then switched to car bodies.

Circumstances not only favored cooperation with General Motors, absolutely all the stars agreed for this. Harley Jarvis remained in charge of the family business, Earl Automotive Works, even after being acquired by Cadillac dealer Don Lee. One truly beautiful day, the general manager of Cadillac and one of the founders of the Fisher Body body shop Lawrence Fisher visited the car dealership. He was introduced to Earl's work and saw in the young man, in his early thirties, an intelligent craftsman, a creative personality and a suitable candidate for the role of the designer of the first model of the luxury brand LaSalle, now long dead.

The Series 303 was somewhat reminiscent of the Hispano-Suiza H6, but as time passed, the maestro stopped looking around. In 1939, Earl's department tore the cover off the streamlined Buick Y-Job, in fact the first concept car in history. A decade later, Cadillac rolled out the third-generation Series 62, with small tailfins a la the plumage of the Lockheed P-38 Lightning twin-engine heavy fighter. Designed by Frank Hershey. Hardly anyone remembers him today.

Since that moment, aviation motifs have captured the imagination of design centers. The creations of the talented Chrysler Corporation artist Virgil Exner appeared on the scene, almost as good as GM products in pomposity. The peak of the "Detroit baroque" came in the second half of the fifties, when the giant tail fins were echoed by taillights a la rocket nozzles, and at the same time thematic decor on the sidewalls. And here let me draw your attention to an exciting circumstance: General Motors really dreamed of something very close to airplanes. They probed the ground, experimented and almost opened the door to an alternative reality.

The Firebird I (originally called XP-21) is a child of the romantic era, when tomorrow seemed bright, high-tech and reactive, and bold prophetic statements poured from every iron. As an example, and a slight lyrical digression, there is an article in The Tacoma News Tribune dated April 11, 1953 with the headline "In the future, there will be no end to telephones." It contains the president of Pacific Telephone & Telegraph Co. Mark Sullivan shared fantastically accurate thoughts on mobile devices with video communication.

But back to Firebird. It resembled a scaled down version of the Douglas F4D Skyray carrier-based interceptor with a delta wing mounted on four wheels. No more and no less. In his article “I Dream of Cars” for The Saturday Evening Post, Harley Earl talked about the origins of non-trivial design.

“Firebird inspires me with its origins. At our 1953 Motorama show, the main dream car was the Le Saber. And right after it was shown to company officials for the first time, I went on a plane trip. I opened the magazine and saw a picture of the new Douglas Skyray jet. This is an amazing ship, and I liked it so much that I ripped out the picture and stuffed it into the inside pocket of my coat. The GM rep who accompanied me came over to congratulate me on the Le Saber. "But what will you do next year?" - he asked. I had absolutely no idea at the time, but I patted my pocket where the Skyray image lay: "It's right here." It was a joke, I was just answering his questions in a similar manner. And then bingo! The result, as you can see, is the Firebird, a road replica aircraft."

The work of Earl and his guys brings to mind the words of the artist Brett Dilosanto from the book "Wheels" by Arthur Hailey. Here, listen: “... they will tell you that no major changes can be made to the model of the car. From now on, they say, we will only make minor modifications and develop existing designs. But that's exactly what the gas industry thought before Edison invented electricity. And I argue that fantastic changes are planned in design. And one of the reasons is that we'll be getting some amazing new content soon."

The General Motors project went beyond stylistic frills and primarily served as a research platform to dive into the then little-known field of ground vehicle aerodynamics. An almost exact scale copy was sent to the California Institute of Technology for testing in a wind tunnel and creating the optimal body shape, calculation of brake flaps and tail angles of attack.

External similarity with Skyray required a special power plant. And here it is exactly like this: under the fiberglass "fuselage" is a gas turbine engine. Prior to the birth of the Firebird, GM had been developing the GT-300 unit for testing on trucks and buses for several years. The prototype fighter received the GT-302 Whirlfire Turbo-Power with an idle speed of 8000 rpm and a power of 375 hp. at 26,000 rpm. Weight - 351.5 kg, which is 31% of the weight of the machine.

Here's how David Temple describes the device and how it works for Mechanix Illustrated. “In the bow of the Firebird is a 132-liter fiberglass fuel tank, and immediately behind the cabin is a two-section gas turbine engine with a gas generator and power section connected by a flexible shaft. The first actually replaces the internal combustion engine and the pump wheel of the automatic transmission torque converter, and the second - the turbine wheel, transmission and rear axle differential.

The rocket launcher sets the aircraft in motion due to the emission of gases (jet blast). In contrast, the Firebird motor directs its exhaust gases through a turbine, which is connected directly to the rear wheels through the transmission. The gas generating section consists of a compressor rotor and a turbine wheel on a common shaft. The air entering the compressor is compressed at a pressure 3.5 times higher than atmospheric pressure. Then it enters two combustion chambers and heats up to over 800 degrees. Hot gas from the gas generator turbine drives the power section turbine. This in turn drives the rear axle through a two-speed planetary gearbox.”

The estimated speed was seen somewhere beyond 320 km / h and significantly exceeded the record achievement of the British gas turbine Rover JET1 (152.691 miles per hour or 245.7 km / h). But the not-so-successful trip of GM Vice President and Research Laboratories Division General Manager Charles McKuen to the Arizona test site discouraged any desire to test it. After the turbine gained high speed, the "firebird" flew at full speed. McKuen released the accelerator pedal before the turn, but did not take into account that this type of installation does not provide engine braking. There was no time for slowing down, and as a result, the Firebird turned over. The pilot was injured, but survived thanks to a head restraint and seat belts, and the "rocket" was repaired and exhibited at the Motorama 1954 exhibition at the fashionable New York Waldorf Astoria hotel.

Road fighter turned out to be terrible? Not at all! According to three-time Indy 500 winner and engineer Maury Rose, who participated in the development, the Firebird is controlled and stable. Despite the “dampness” of the design, the front torsion bar suspension on double wishbones and the rear “De Dion” made it possible to achieve decent behavior. The brake system is quite interesting: drums with a diameter of 11 inches are placed not inside, but outside the wheel for the fastest and most efficient heat dissipation.

“With absolute sincerity, I can say that the car itself is an outstanding work both in terms of style and engineering,” Rose said in a Motor Life article.

The concept of a gas turbine vehicle captured the people of General Motors so much that in 1956 they introduced the Firebird II (XP-43). This time, not for egoists, but in the name of… family values! The length of the aircraft-like body with a four-seat interior is almost six meters. The Whirlfire GT-304 (203 hp at 28,000 rpm) is more efficient, economical and quieter than the previous monster, and the exhaust gas temperature has dropped to the level of the internal combustion engine.

The second iteration turned out to be prophetic in a certain sense. It's not about gas-oil chambers instead of springs and shock absorbers with the ability to maintain a constant ground clearance, regardless of the load. Not in experimental disc brakes. And not even in the air conditioner, which is vital in a glass cabin with a "greenhouse effect". Dr. Lawrence Hafstad, Vice President of GM Research Laboratories, and his team have virtually equipped the Firebird II with unmanned technology and integrated it into the automated road infrastructure of the future.

For autonomous movement, the driver turns on the toggle switch and "fits" into the transport system with impulse strips. The incoming electronic signals control steering, acceleration and braking via the on-board computer. People, meanwhile, go about their business, reading books, watching TV, or just staring around. An important role in the futuristic show is played by control room operators - according to legend, they help with finding free rooms in roadside motels, and can also control the fuel level and engine operation, synchronize the speed and direction of movement, or, in case of a malfunction, remotely direct the car to a safe place.

In 1958, Harley Earl left General Motors and left in his legacy the Firebird III, "an entirely new type of vehicle that can be used to get to the moon launch pad." By the way, the Jeim miracle itself resembled a spacecraft with cockpit hemispheres and seven tail fins.


The more compact and lighter gas turbine GT-305 (228 hp at 33,000 rpm) with a quarter improvement in efficiency was assisted by a 10 hp two-cylinder aluminum engine. for driving air suspension, air conditioning and other electrical and hydraulic on-board systems. Isn't it remotely reminiscent of the scheme of sequential hybrids, when the internal combustion engine is in no way connected with the wheels, but is only a generator for the traction battery?

Without cruise control and anti-lock brakes included in the Firebird III equipment, modern technology is unthinkable. But the exotic Unicontrol joystick with which the aircraft accelerated, turned and slowed down until it found application.

It is rather strange to see axle beams on subframes in the midst of this high-tech, but there is a nuance here: the front and rear gas-oil elastic elements are combined with each other to increase smoothness, reduce disturbances from the road surface and maintain a constant ground clearance.

The fourth Firebird of 1964 will be bracketed out as it is not a functional layout. Although, of course, beautiful!


Author Administrator  Sci & Tech  0  670
engine_05.jpg
27 Aug 2022
Small engine builders turn small engines into big ones, and big ones into huge ones.

Small engine builders turn small engines into big ones, and big ones into huge ones.
Even a small firm can create a completely new engine from scratch - of course, if there are competent designers, a foundry and metalworking machines. But it is often more reasonable to take a serial design as a basis ... and “multiply” it one and a half to two times. So you can get a V8 from an ordinary in-line “four” ... or, say, turn a serial V8 into an exotic V12.

By itself, the idea to scale an existing engine did not appear yesterday, and large car builders adopted it a hundred years ago, if not earlier. I will give the most famous examples of such a concept. The inline "six" BMW M30 of the late 60s was obtained by adding a couple of cylinders to the "four" M10. The legendary five-cylinder engines of the Audi EA828 series of the early 80s were created on the basis of the four-cylinder EA827. Subaru SVX's six-cylinder boxer EZ33 is a one and a half times EJ22 engine. And the 12-cylinder BMW M70 engine is, in fact, a pair of M20 “sixes”, united by a common crankshaft.

This approach has a lot of advantages: both the acceleration of design work and the unification of components - you can use the existing parts of the gas distribution mechanism, pistons, connecting rods. It is also convenient for production: ready-made tooling and machining lines are used.

For small motor-building firms, these advantages are even more important. For example, the ability not to waste time and money on choosing the best head design, on testing different options is a great help if your company produces dozens or even units of engines a year!

V8 Honda:
Honda is famous for its four-cylinder engines. For example, back in the late 80s, B-series engines with the VTEC system reached almost motorcycle boost rates, breaking the magical mark of “100 horsepower per liter”.

The K-series engines, produced since the beginning of the 2000s, not only take up space under the hoods of most Honda and Acura models, but have also become super popular in motorsport and tuning: they are put on prototypes for the “ring” and mountain races, installed on cross-country buggies, transplanted in rear wheel drive Fords, Lotus Elise and even Ferraris. But the Japanese company has never mass-produced V8 engines: the maximum is V6.

American engineer Craig Williams dreamed of building a supercar with a 12-cylinder engine of his own design for many years. But in the end I decided to start a more realistic project - to create my own V8. And he admitted that he was inspired by the example of John Hartley!

At first, he thought to take as a basis the legendary F20C engine from the Honda S2000 roadster - the unit that already “spun” up to 9000 rpm from the factory and produced 240 horsepower without a boost. But in the end, I decided to stop at a much more massive and cheaper K24 engine with a volume of 2.4 liters, which in different versions develops from 160 to 205 horsepower. Williams admits that the impetus for the start of work was poor health: the engineer was diagnosed with a serious lung disease, and the design allowed him to distract himself during treatment.

The Neutron K48 engine is a torsional V8 with a classic 90-degree camber angle and a "flat" crankshaft. For the sake of reducing the cost, Williams decided to use standard heads on both sides - for which use two timing chains at once, front and rear.

True, the choice of a V8 scheme with a “flat” crankshaft promised problems with vibrations due to a very long-stroke design: the piston stroke of the Honda engine is 99 millimeters. To get around these difficulties, the designer decided to use ultra-light titanium connecting rods and very compact pistons.

Since production is planned in very small batches, Williams preferred at first to machine the block from a solid aluminum billet. True, not every block can really be made in this way. Therefore, Williams decided to simplify the design: Darton quad cases should be installed in an empty block. And only then, when the design is worked out, it will be possible to switch to casting.

The American took up the design in 2016. The mechanical part is basically completed, the dry sump lubrication system is ready: now the designer is working on the intake system. Williams lays down two versions of the motor. Firstly, a high-speed "aspirated", which should spin up to 10 thousand revolutions per minute and produce up to 700 horsepower. Secondly, a supercharged version with a pair of turbochargers in the collapse of the block. Will we see results soon? Craig Williams hopes to assemble the first prototype by the end of the year - if only he had enough health ...

By the way, the PPR Motorsport workshop is also engaged in a similar project. The Turkish company specializes in the manufacture of original turned blocks and heads - primarily for drag racing. The K44 motor should retain the common architecture of Honda's K-series four, but the block and heads will be made from scratch. Two versions of the engine are supposed: a road V8 4.4 with a capacity of eight hundred forces and a drag version of the V8 5.2 with a capacity of a thousand forces. But this project is still far from completion: judging by the photos on social networks, only the heads are ready yet.

Huge "little blocks"
Chevrolet Small-block eight-cylinder engines are one of the most successful and massive engines in the American auto industry. They power everything from work pickups to Chevrolet Corvette supercars and show surprisingly high boost potential. And they also served as the basis for two V12 engines at once!

The author of one is the American engineer Ryan Falconer. He is a real motorsport veteran: he has been building racing engines since the sixties, even having time to work with Carroll Shelby. His track record includes engines for Indicars, for Can-Am series cars, for various racing projects of the General Motors concern.

Falconer said that back in the eighties, a friend of his suggested combining a pair of Chevrolet V6 turbo engines that they were preparing for the IndyCar series to install them on an airplane. Ryan really liked the V12 engines, but he preferred to build on the time-tested and reliable "small-block" engine.

In 1990, the Ryan Falconer Racing Engines V12 engine was ready. The first prototypes were literally welded to the serial "eight" four more cylinders. But the V12 engines launched into small-scale production were already manufactured in the normal way - by casting their blocks and heads.

By the way, the Falconer V12 is made entirely of aluminum - although the then Chevrolet LT series engines had a cast iron block. But otherwise, he repeated the architecture of the usual "small block": the design of two-valve heads, a 90-degree camber angle, the location of the camshaft in the block ...

Engines were produced ranging from 400 to 600 cubic inches (6.5–9.8 liters): naturally aspirated, turbocharged or driven by compressors. They were mainly used on boats and small aircraft. They were rarely put on cars due to the lack of environmental certificates - mainly on various kinds of hot rods and custom cars. Although in the early 90s, General Motors even built an experimental Corvette ZR-12 with this engine. So GM was going to confront the Dodge Viper - but in the end the project was abandoned due to complexity and high cost: the only prototype built is in the National Corvette Museum on Bowling Green.

A similar motor was introduced in 2016 by the Australian company Race Cast Engines. As you might guess from the name "V12LS", the brothers Matt and Shane Korrish took the "small block" Chevrolet of the previous generation as the basis: the 90-degree camber angle, the location and dimensions of the main components, all the mounting dimensions of the motors of the so-called LS-series are preserved.

The design of the heads and the shape of the channels are "copied" from the Chevrolet LS7 motor - a very successful "power" design. There are two block options: cast iron, with a cylinder diameter of 104.8 mm (as on the 7-liter LS7 engine from the Corvette Z06) and aluminum, with a cylinder diameter of 103.25 mm (as on the LS3 engine with a volume of 6.2 liters). The only crankshaft is steel, with a crank diameter of 92 mm (as on the LS3 motor). This results in two displacement options: 9.2 and 9.5 liters (564 and 580 cubic inches).

On average, such engines with a moderate “civilian” profile camshaft develop about 750 horsepower, with a more extreme one - about a thousand. Curiously, the mass of the engine turned out to be not so large: without attachments and collectors, the aluminum version weighs 191 kilograms. Cast iron is much heavier - 265 kilograms.

The Australians offer both ready-made motors and sets of spare parts for construction by a qualified mechanic. The latter are relatively inexpensive: 39 thousand dollars. We have already seen the Australian V12 under the hood of a custom Chevrolet Camaro, Cheetah Evolution and Factory Five F9R sports cars.

Inline “sixes” of the Toyota JZ series are a real tuning legend: durable engines with cast-iron blocks calmly “hold” 650–700 horsepower, and extreme variants for drag racing can produce over two thousand horsepower.

But the American engineer and hot-rodding enthusiast Don Groff from Minneapolis went a radically different way, assembling a homemade V12 engine from a pair of 1JZ-GTE engines! Instead of making the original V-shaped cylinder block, he cut off the bottom of the blocks and installed them on a homemade crankcase. Moreover, I chose an extremely unusual camber angle - very wide, 120 degrees. The original crankshaft was custom made by SCAT.

Unlike other designers, Don placed the entire timing drive on one side of the motor: for this, one of the heads had to be redone. Moreover, he chose a rather exotic “Hot-vee” layout with a release in the collapse. Initially, he supplied the engine with as many as four turbines, but in the end he simplified the design - he left two turbochargers.

From the idea to the finished car, it took Don almost nine years: the engineer built his motor specifically for the racing “formula” in a retro spirit. Which he not only assembled on his own, but also managed to register as a car for public roads!


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