How Long Do Jet Engines Last ? 

If you did work on engines, would you be fascinated by videos of a guy talking about doing your own job?

Ah, There's a special joy to touring on a big bore 4 cylinder sport bike. Went to Montana on a Honda 929, and had a really nice time.

I like the part about waiting for his brain to warm up.

"Zen.." was one of the best books I've ever read. Had to read it in high school and understood almost none of it. Picked it up 5 years later as a college graduate, and it blew my mind.

To an accountant, nothing I do makes sense. I could make more money working on trucks. But it's the intangibles... I've been in jet warbirds doing barrel rolls in the sky! Have a look at my video called Warbird Jets to see what I mean by intangibles.

@@AgentJayZ Your jet warbird video…great video of what looked like an awesome event! I understand exactly what you mean. There are experiences that money just can’t buy and those are the rewards of doing what you do. Of course you are wise and seek out or create those opportunities so good on you! One of my family members from way back was what they referred to as the “Engineer In Charge” at the Orenda facility when they were developing the Arrow. He’s long passed now but it would have been interesting to hear his stories. He spent the rest of his career after the program was so unceremoniously snuffed out working for the government in “Weights and Measures.” I’m thinking maybe his spirit was shattered by it all. I’m glad to see you keeping those engines alive. The folks who worked so hard to develop them would be very happy to see that. As for me, I’ll stick to antique one-lung farm pump engines from the 1920s. Even those are kinda neat. Keep doing what you do Mr…it’s great!

And were you aware that the J48 was a licence-built version of the Rolls-Royce Tay engine, which was a derivative of the Rolls-Royce Nene, which was also licence-built as the J42?

This is a good description of the issue that will eventually present itself. When such bearings are produced, they will need to be tested to the satisfaction of the operators of the engine.

I like that almost everything is made of Aluminum or stainless steel. I rarely deal with rust and mud, like I have to with automotive work.

I think you might have the second coolest username ever... next of course to rocketwaffles !

The little linkage is steel in this motor. Noise completely disappeared after adjusting the valves.

Those Olympus engines might be valuable to an industrial buyer.

As a Bristol Siddeley Coventry apprentice, I visited the site during their commissioning (they were the original Industrial Olympus 17.5MW sets) and saw one of them run up, I think it was for the first time but, at this distance in time, I can't be sure. PS When they were first installed, they didn't have Rolls-Royce nameplates.

Unfortunate to be decommissioning a working plant.

You are correct. Simplified for brevity, and because most viewers are unaware of such details. Many CL-13s are painted up in USAF colors, and labelled as F-86F. I would bet that you know the two main reasons why...

If you watch my Oshkosh vid called Warbird Jets, I'm in the backseat of an aircraft that does a barrel roll. It's powered by a turbojet engine that uses a double sided, single stage centrifugal compressor. I might make a video about engine sizes, technology, and costs.

The first generation turbojets (the successful ones) all had centrifugal compressors. The Whittle WU, W.1, W.1A, W.2B, the R-R Welland (derived from the W.2B), Derwent, Nene and Tay, the DH Goblin and Ghost all had centrifugal compressors. And so did von Ohain's original engines, including the HeS 3, the first ever turbojet to fly in the He 178. However, it was good for only a few minutes flight time and the aircraft's first landing was unpowered.. In comparison to the British centrifugal engines, the German wartime axial flow engines were grossly inferior in almost every respect - except for their frontal area. The first successful turbojets in the USA all used Brit technology. The P&W J42 was a licence-built Nene and the J48 was a licence-built Tay. And, of course, the Klimov VK-1 in the MiG-15 was a reverse-engineered R-R Nene (with a few tweaks). It produced a little less thrust that the axial flow GE J47, was slightly less efficient in terms of specific fuel consumption, but was significantly lighter.

I've given you an answer to Part One of your question, now here is an answer to Part Two. I presume you've taken a good look at the blading in the compressors of the Orenda engines that AgentJayZ has shown us? Perhaps you have also seen the compressor blading of the J79s and LM1500s that he has worked on? Now try to imagine those scaled down geometrically to the size of the little centrifugal turbojets that are used in R/C jet aircraft models. The blades and vanes would be impossibly thin and fragile: they would be like tiny razor blades. And the various clearances, both radial and axial, could not be scaled. To be practicable, the blades and vanes would have to be relatively larger, both in thickness and in chord. Now imagine those blades and vanes scaled back up to the size of an Orenda or a J79. They would be ridiculously thick and their chords would be unnecessarily wide, making the compressors excessively long. Aerodynamically, those compressors would be significantly less efficient than the real Orenda and J79 compressors. - and so are the actual 'miniature' axial flow compressors that various people have tried to construct. In practice, they are relatively even more inefficient, to the extent that they often do not work. PS I used to be a regular visitor to a local model engineering show here in the UK, at which members of the Gas Turbine Builders Association exhibited their little centrifugal engines, including running one or two of them. However, there was one exhibitor who turned up with the components of his little axial flow engine: to the best of my knowledge, it had never actually run.

Orenda says 400 hours.

Really? At 70 thousand miles, mine looks new inside.

If you want one, we have a few "circuit boards" from the 1950's Sabre. Empty tube sockets and all. I have no idea what they are for, but maybe the analog "computerized" gunsight. Eh?

I don't know all the details of how it's done, but it's not like a mold or a press that can be quickly swapped in. The machines are all universal, and are configured for high volumes in the thousands of bearings. This would need to be stopped, and changes would need to be made in forging of the basic parts, machining , grinding, measurement, inspection, testing and quality control, certification of performance, engraving or labelling, packaging, inventory. If the factory has hundreds of workers, making thousands of units per day, and generating a decent profit margin, how many units need to be ordered to cover the interruption and delay involved with setup for a new product? I doubt it would be worth their time for anything less than a thousand items, and even then a significant "low volume" premium would need to be paid. Anyway, no manufacturer we've talked to is interested in such a puny amount of money, and no owner has so far been interested in paying such a huge amount of money.

@@AgentJayZ for industrial use is adapting another available bearing an option?

@fuzzy1dk As someone who was involved in the design of aero-derivative industrial engines, I would say no. An operator would expect at least the same level of reliability as the original engine - as they believe they're paying for it. In fact, the industrial version might need a better standard of thrust bearing because it has to take higher loads at ground level, as compared to running at altitude.

"the work of gearbox"... ... is to be a gearbox. Over.

If it was termed an Accessory Gearbox (which is what it is), would that help? It can drive fuel pumps, oil pumps, hydraulic pumps, an electrical generator, etc.

Of course, being a RR design engineer, you are a knowledgeable guy, and a nice guy.

From a physics perspective, I think you can achieve higher rpm while stationary. At high speed the fan will be consuming more power to produce the same thrust. It would be really interesting to hear what the absolute gentleman JZ himself has to say about this.

The static thrust might seem to be more than the moving thrust, because the speed differential between the exhaust air and the atmosphere is greatest when the engine isn't moving. But, as the engine is moving through the air, as it would be when propelling a flying aircraft, the inlet air is also being rammed into the engine. The fan is designed for best performance while flying at several hundred km/hr, and at full engine rpm. The LP, N1, or Fan rpm would be lower on static test because of 2 factors: no ram effect, and the air is more dense on the ground than it is a few KM in the sky. The different rpm's for the N1 system, static on the ground, and at any speed in the air, are all within the operating limits of the engine. If either the fan (N1) or the core(N2) were to get to their maximum rpm, the fuel control would modulate fuel to keep those values from exceeding the max limit. Full Authority Digital Engine Control. The full authority bit means the computer is in charge.

@@AgentJayZ you answered that for me very well.

@@ChemEDan I think you aren’t considering the Angle of Attack change (reduction in AOA) due to forward motion. Statically, the AOA is basically the angle of the fan blades.. with forward motion say in flight, the AOA is smaller, which should unload or make less drag, allowing the rpm to be higher.. a good example is an airplane with a fixed pitch prop. On takeoff, it might only make 2250 rpm. In flight, it could be 2700 rpm or more if you let it..

Speaking about the J79, the Variable Stator System adjusts for inlet air pressure and density, and the entire compressor system is designed for conditions of full rpm and max ram pressure. The inlet duct, which is part of the aircraft, adjusts its geometry to maximize ram pressure and to keep the inlet air subsonic, even if the aircraft is travelling through the air at supersonic speeds.

We are working on that, but we are not there yet.

@@AgentJayZCNC machining and metal 3D printing technology has come a long way, its pretty exciting

Turbine blades are not machined, except for the roots. Certainly we can print the blades... the difficulty is nobody wants to risk their multimillion dollar engine to test if they can handle the working stresses.

Does that matter? You are definitely not the first to watch it, because it's too long for that. You're the first guy, after the first guy, to be the first of the followers of Kathaleen. She was first, anthonynotwatcher was 2nd, and you are the third viewer to not view the vid.

@@AgentJayZ These accounts are kinda bot'ish lol

Maybe I should add a target word for my gate-keeping robots? "first"? I don't know... those guys are really quick on the trigger.