No Jets

Very good. However, the flying wings, like those designed by Reimar and Walter Horten and Glen Northrop, were highly impractical, dangerous, and unstable. The Northrop XB-49 was a prototype for a flying wing bomber similar to the B-2. The test pilot was told by another test pilot NOT to stall it
out because it couldn't recover from a stall. However, the Air Force wanted to see how it performed in a stall. So it ordered a stall test. The test pilot of
the second XB-49 put in a stall and it stalled out and crashed killing the test
pilot. This was at Muroc, later Vandenberg Air Force Base, where the sound barrier had been broken by Chuck Yeager.

Okay, just for the record I need to clear up a little information here. The flying wing aircraft shown in the photo is actually the Northrop XB-35. It was powered by Pratt & Whitney R-4360 radial piston engines, not turboprops. The lack of performance of the aircraft compared to more conventional types, and the extreme problems encountered with the contra-rotating props led Jack Northrop to propose replacing the R-4360's with 8 Allison J35 jet engines.

That led to the YB-49. While the performance turned out to be quite good, the aircraft was unstable and a poor bombing platform (it took the sophisticated computerized avionics of the later B-2 to solve this problem). The 2nd YB-49 did indeed crash on a test flight on 5 June 1948 while flying from Muroc Air Force Base. The copilot was Captain Glen Edwards and after the crash the base was renamed Edwards Air Force Base in his honor. Vandenberg Air Force Base is near Santa Barbara, California and is an ICBM missile base and the home of the Western Launch and Test Range for space launches.

The Air Force officially listed the cause of the crash as unknown. Without "black boxes" and with the death of the entire crew, it was very difficult in those days to exactly determine what went wrong. There is some speculation that they crew was trying to recover from a stall, but there is no evidence to show that they deliberately put it into a stall for a test.

The Boeing B-50 was a variant of the famous B-29 Superfortress with more powerful P&W R-4360 engines, the same powerplant that was in the XB-35.


Dave

www.pigboats.com
 
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Boeing model 400 XF8B.
This is a pretty one for the 50s in this timeline.

http://en.wikipedia.org/wiki/Boeing_XF8B

boeing_xf8b.jpg
 
I practice the black art of thread necromancy to make a few points that were never made, or at best obliquely alluded to, in the year this thread ran:

While it is not entirely implausible (see my last point!) that both Whittle and Ohain might have had the success of their engines butterflied away, I do think that the development of the turbojet was close to inevitable, barring the total collapse of technological civilization. In particular the type of turbojet Whittle settled on for practical early development, using a centrifugal compressor, was essentially a glorified turbosupercharger. By the time WWII started a number of planes already had turbosuperchargers incorporated as basic parts of their engines and in the course of the war it became standard in many types of plane. Some kind of supercharging was essential to achieve decent performance at high altitudes and turbosuperchargers inherently tend to become more effective as the air thins. To be sure, Whittle had to greatly improve on the compressor's pressure ratio, tolerance of heat (and still more in the turbine side of it of course!) and mass flow; relative to an off-the-shelf turbosupercharger his achievement was tremendous. But in concept it was basically the same thing.

Furthermore, the most advanced piston engines of the late war and post-war period actually extracted a significant amount of their output horsepower from the turbine of their superchargers--this was called IIRC a "compound engine." The basic concept of a turbine that extracts useful power from a gas flow was thus not only quite familiar in theory but realized in practice quite as a byproduct of piston engine development. To be sure that was in principle a variant on the "motorjet" concept of using a piston engine to drive the compressor and it was not used to generate a gas jet but rather to augment the prop torque.

But meanwhile airplane designers were also designing radiators or the airflows around radial (aircooled) engines to use the radiated heat to augment the flow and thus provide significant thrust when exhausted; again this was a byproduct.

It's pretty hard for me to believe that someone somewhere would not look into the possibility of using the turbine exclusively, bypassing the piston engine completely, and then integrating all this insight into how to use waste heat to aid the thrust into designing ducts to harness the heat directly into a jet.

Perhaps a decade might intervene; perhaps without a big war to force lots of ideas to be tried (including alternatives that failed but might initially look more attractive) it would take a while to get going, and meanwhile perhaps WWIII would end civilization, thus mooting the jet engine.

But once developed the jet proved very attractive in various forms. First it conquered the realm of high-performance military aviation despite its early drawbacks (mainly being very fuel-hungry--the earliest jets were also unreliable but their basic simplicity compared to piston engines allowed them to pull even and surpass the highly developed but basically tempermental pistons remarkably soon); then as they became more efficient and reliable, they took the world of civil aviation by storm because however loud an early 707 or Comet was to people on the ground in the neighborhood of the airport, for the passengers they were much quieter and the nasty vibration that made piston planes so wearying was largely eliminated. Their speed (which, true, wasn't dramatically faster than the best prop planes--but still, faster) was another plus and eventually with the development of turbofans coupled with much bigger airframes, they proved to be more fuel-efficient as well. Even before that, the airlines saw a dramatic improvement in the overall cost-effectiveness of their operations; not only did faster (and soon, bigger) planes mean more passenger-miles per year of operations, they saved a lot of time and money due to the turbine's simpler maintenance and longer time between overhauls--more of a year was spent carrying passengers and freight and less in the hangar.

A world without jets is a world where aviation is simply less well developed, across the board. Helicopters too were revolutionized by being able to replace the heavy and tempermental radial engines with turboshaft power plants. Even prop planes today, except at the most modest level of light planes, have gone over overwhelmingly to turboprops, because they are lighter, just about as efficient, more reliable, and quieter.

Now on the other hand--if one wants to take Whittle out of the running :)eek: he's one of my heroes!) it is true that when he started testing his first model of experimental turbine engine, it started to spin out of control--so he cut the fuel and it kept on accelerating after he'd cut it off completely! Turned out it was aspirating lubricant oil in its sump and burning it up quite happily.

I suppose there is a real chance he might have died right then and there, and with him perhaps all British efforts at developing the radical concept--at least until those Messerschimtt fighters started intercepting allied bombers and fighters over Germany.

Stopping Ohain would probably require a more determined ASB.

And in the end, perhaps long after the war, the idea was just too straightforward and too much in demand not to have been developed by somebody.
 
Without Whittle the British would probably have a completely different view of A.A. Griffiths. Theoretical discussions of jet efficiency gave different results depending on the temperature assumed for the hottest parts of the engine. As metallurgy advanced, the jets would become more efficient theoretically as well as practically.
 

Shooter

Banned
Hate to pop your balloons, but...

The first jet engines were made around the turn of the century, BEFORE WW-I! There were at least four working examples made long before WW-II, none of which could effectively power a plane. One of them required three compressors in parallel to force enough air through the combustor to sustain a flame. The first patent was granted in the 1700s! Turbine and Jet engines are nothing new, it was only the state of the manufacturing art that needed to catch up!

Then there is Henri Coandă who actually built and flew a primitive "Motor Jet" in 1910, IIRC! He was only the first of several who tried before Junkers and Ohain succeeded! Once DeLavel invented the convergent/divergent nozzle that made steam turbines efficient, it was only a mater of time before many people thought that turbines would also make a "Jet" engine practical.

As to Titanium being required to make jet engines, Bah Humbug! The Super alloys that make jets (and Turbo-chargers buy the way) efficient are Nickel alloys. Titanium only make the non critical parts lighter than steel, most of the case is made from Aluminum alloys.

Finally, there is the idea of Airships used for passenger transportation. It was not and never will be a practical or cost effective way to do that! Cross country fast trains doomed all but ocean crossings and once airplanes could make the trip, air ships were doomed to total economic failure! By the time the first practical air ship, Graff Zeppelin, was sorted out and plying it's trade, fast ships were only a few days behind and a great deal less expensive per person. The Trans-oceanic cable had made getting there in person for critical-time sensitive business redundant and wasteful.
 
Oy vey! I can't believe how terrible my early threads were. Ghost of Threads past, stop bringing me back!

But its so fun!

To address the thread, of course the basic situation is nearly ASB, but.....

If jets (including turboprops, I'd expect) were never invented, aircraft performance would pretty much top out at late WW2 standards for normal operational aircraft. No matter how powerful the engine or advanced the aerodynamics, the presence of a propellor would limit maximum speeds to the low 500s mph. Also the compressors of jet turbines are useful in cabin pressuration, so I suspect there woud not be as widespread use of pressurized crew/passenger cabins. Finally, turbojet engines provided a degree of reliability, speed, and comfort to long distance air travel that could to be acheived by piston engines.

You might see more widespread experimentation and operational use of liquid-fueled rocket engines for certain types of aircraft where extremely high speed and climb rates are essential.

Possibly more serious exploration and implementation of sub-orbatal DynaSoar type technologies for high speed trans atlantic/transpacific military and commercial uses.

Conversely, in a world without jet airliners, as suggested by previous posters, you might see the survival and continued development worldwide of much slower forms of transportation for long-distance travel, ocean lines, high speed trains, and yes, airships
 

Shooter

Banned
Okay, just for the record I need to clear up a little information here. The flying wing aircraft shown in the photo is actually the Northrop XB-35. It was powered by Pratt & Whitney R-4360 radial piston engines, not turboprops. The lack of performance"

The
performance when compared to other prop planes was absolutely stellar! The top speed of 393 MPH at a time when the fastest B-50 and B-36 could not make 360 MPH and, again depending on load and range considerations could cruise at 361 MPH with a bomb load of 16,000 pounds over a range at 245 MPH greater than 8,600 miles. You are right about the gearbox/prop shaft problems, but they were/are easy to solve once you know what they are, torsional vibration, which was a very new thing back then. ( The science, that is!)
But the single largest and seemingly most insurmountable problem was lack of political clout and the re-design required to carry the Atom Bomb. The most grievous aerodynamic problem, pitch instability, was solved by the first fly by wire ( Stability Augmentation System!) system! Note that the B-36 never did reach the same operational range until the Featherweight program!

That led to the YB-49. While the performance turned out to be quite good, the aircraft was unstable and a poor bombing platform (it took the sophisticated computerized avionics of the later B-2 to solve this problem).
The Boeing B-50 was a variant of the famous B-29 Superfortress with more powerful P&W R-4360 engines, the same powerplant that was in the XB-35. Dave www.pigboats.com

Note that the engines in the B-50 WHILE SIMILAR, were more advanced than those in the B-35 3,500 to 3,000 HP! Also note that even with the more powerful engines, the B-50 could not fly nearly as fast and high to avoid flak and interception, or as far, or carry such a heavy load as the B-35. Second note, neither could the B-36 until the D Model which was faster, but shorter ranged, with a lower cieling and carriing less bombload at range.
Don't you hate it when political pay offs spoil a possably great plane!
 
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