Those GE F101s run hot.

The power plant I used to work at had 4 Units, plus Unit 6 ( I know, out of sequence) for peak generating periods...………...It is a jet turbine inside a building, and is loud as hell

I don't know about other engines,  but the turbine parts of P&W F100s and 119s don't spin faster when in AB. Engine RPM max's out at MIL power.

And fuel isn't just dumped in the exhaust.  They are a series of fuel spray rings inside the afterburner section that are carefully controlled. A couple igniters (think large spark plugs) are used to ignite the fuel.

Thanks. That makes sense. Especially the turbines having a max safe operational speed.

Compressor, burner, turbine.

Air goes in and combines with money...lots and lots of money then makes noise

Simple? lol, operating 3 of these in combined cycle. Suck, Squeeze, Bang, Blow

Attached File


Turbine section, real simple.

Attached File


Link to Siemens, turbine description and neat info

Efficiency and reliability are good, but still maintenance heavy engines.

This. The general theory of jet engines is simple. The application of the theories in any useful manner is insanely complex and expensive.

I love jet engines but my ears are still ringing from hearing them 3 hours straight at the Daytona 500.

Those jet dryers are fucking LOUD !!!

Steam is one of the best working fluids, period. Nothing crude about it.

Got a spare turbo or some time to go grab one at a pull-a-part?

All you need is some exhaust pipe and a really fat section with two holes drilled into it... one for a spark plug and one for a fuel nozzle. Add an electric motor with an oil cooler for lubrication and poof! Jet engine.

Afterburners do nothing to speed up the engine. They just dump fuel into the exhaust stream after the power turbine, which ignites and increases thrust because of thermal expansion. Or something along those lines.

Jet engines are RACIST!

they need to be made in diverse countries

Jet engines are based on the Brayton Cycle, a deriviative of the Otto Cycle.

Steam Turbines and power generation is based on the Carnot Cycle.


Turbo Fans were invented to reduce noise and improve fuel efficiency.  Jet engines provide better thrust in a smaller profile but are noisy as hell.  Imagine a jet engine strapped to the wing of a 737...no one would sit behind the wings...lol

I flew on 737's without turbofan engines, along with 727's and 707's and DC-8's.
Nobody went deaf in the aft cabins.

Some of that is the limit of the wings being able to provide enough lift. the thinner the air, the less lift the wings can produce. (kinda like density altitude, but it is real altitude)  The Sled could fly higher partially because it flew a lot faster than the U-2

Simple in principal.  But they are complicated as hell in the details.

None.  but you have to already be going stupid fast for them to work.

Robinson does mostly recips, I think they do have a turbine model too though.

Recips are a cost saving measure to make Robinsons "affordable."

Efficiency makes em maintenance heavy.  F machines are pretty reliable, but the new stuff has 2000 degree firing temperatures.  Think about that for a minute.

Real interesting video out there about the SR71 engine. As it gets to speed and certain ducts open for aiflow around and into the engine, it turns into a ramjet. The turbo portion is bypassed at that point.

Sam Chui rode a 737-200 in Canada and didn't go deaf. They're not Ilyushin IL-76s, now those are a loud bird!

yes, they are relatively simple (ie compared to a 1950's turbo compound radial like the Wasp Major).

However they require sophisticated metallurgy and precise manufacturing that can run ad extremely high temps and RPM's for long periods of time without catastrophic failures.

Obligatory

https://www.youtube.com/watch?v=dYFYZ-g7fzA

Isn't it the engine for the 777?

The SR-71 was still flying when I first assigned to Okinawa. Starter was two automobile engines coupled together. They must have cranked both up to near redline to turn those turbines fast enough to light off...you could hear them howling from a mile off the flight line.

TF-33s on the AWACS had a small ring that protruded out of the cowling just behind the fan. If the starter control valve failed, the motor could be manually started, on the ground, with a two foot long rod with a hammer-head rocker on it. Crew in seat (of course), you climbed up a step ladder and stuck the heel of the hammer in the ring. The crew chief would give you a hand signal, and you'd pull the hammer handle down, pulling the ring out to manually open the valve. Had to hold it open until the crew got ignition...crew chief signaled you to release, then you unhooked the hammer, grabbed the ladder and ran like hell. It's like pulling starting a 20,000 hp lawnmower. I've done it several times

The TF-33s on one of the Rivet Joints (RC-135W, I think) had constant speed drives on the (huge) engine driven generators that had to be adjusted, by hand, with the engine running. The tool was a t-handle about a foot long with a allen head welded to the tip. They'd start the engine, and you had to crawl under it just aft of the fan (again), then push the tool up through the fan blast to engage the allen in the socket. Crew chief would give you the "up" or "down" signal until they got the frequency they needed on the flight deck gauges. It's weird as shit to lay on your back under a running jet engine that size, it vibrates your insides and is moving the whole time, like a boat bobbing in the surf. Done that way too many times.

Most fun was de-pickling a motor after an engine change. They put some kind of preservative in them when they're overhauled, and it gets burned off the first time you crank it up on the aircraft. Fire department comes out, and the poor dope-on-a-rope (crew chief on ground cord) gets as far from the jet as possible. It produces a cloud that can completely envelope the aircraft. Seemed kind of cool at the time.

Only jet-related activity that ever really kind of scared me was the man-on-a-stand run on the AC-130s. They wrapped the casters on the stand in chains to keep the stand from being dragged in that big-ass swinging prop, and adjusted the pitch to as close to neutral as possible. You're literally two or three feet from the world's biggest mix-master, and it's hypnotic in a bad way. Never enjoyed that, ever.

I'd say that most helicopters today use turbines.  More simple, more efficient, greater power-weight.

With few exceptions it's to turn shafts, and not provide thrust.

DSC_5088-Ko Turn Crop by FredMan, on Flickr

DSC_6426-Spray Cloud by FredMan, on Flickr

N104HH Hot Loading by FredMan, on Flickr

PAT17091 Outbound by FredMan, on Flickr

Oldie but a goodie, jet engine beer cooler

http://asciimation.co.nz/beer/

I once worked for a guy that put a 737 engine in a fishing boat.

M1 Abrams Tank has a "jet" engine.

If you think they're simple in construction, as opposed to simple in theory, watch Agent JayZ vids.  He's a jet power plant A&P from Canuckistan.  I am astounded at the construction of the fan blades, with very small cooling channels from the center to the edge.  There is some beautiful engineering and machining in those engines.

@M82Assault

Nope, though a “Boeing” does have this engine hung off of it, and it is in current airline use today.

727’s and 737’s always had a turbofan as their powerplants. JT8’s are turbofans, really low bypass turbofans, but they have a fan nonetheless.  

Exceptional post.

Thanks for taking time to write that.  I dont know why I've never thought about being near a running turbine.  Now I have.

But wait, wait...there's more!

Pickled engines were awesome! Just make sure you tell the fire department guys in advance.

I don't think I would like being that close to a 130 prop either.  My biggest pucker moment running engines was my first burner run after finishing engine run class. I was running an F-15E in a hush house troubleshooting an engine stall in the #2 engine.  I ran it slowly from idle to max AB a couple times and nothing happened, then I slammed the throttle from idle to max AB.  That caused a nice compressor stall that sent a huge fire ball out the intake,  over the canopy, and down the #1 engine.  Turned out the nozzle control was binding and not allowing the nozzle to open up fast enough when you advanced the throttle quickly.

I'm still amazed at the level of complexity on the F-15, and that you all are able to maintain the FMC/MC rates that you do, especially considering its Control Augmentation System, variable intake angle mechanisms, variable intake ramps, and everything associated with the engines.  Never mind E&E, fluids, avionics, radar, airframe, weapons, etc.

MD88/90?

Or the B717?

I'm just throwing shit at the wall to see what sticks at this point

I worked F15C/D/Es for 10 years and 6 years on F-22s. I would take working 15s over 22s every day of the week and twice on Sundays! And every Crew Chief I know who as worked both will say the same thing.

There was an interview with a career F-15C driver (20yrs) who flew F-22s his last 4 years.  He said the maintenance was less on the F-22 compared even with the F-16.....if you didn't include the RAM.  Is that your perspective too?

Compressor stall on the line sounds like a cannon going off. I can't even imagine what it sounds like in a hush house. Wonder who the first guy was that decided running a jet inside a building was a good idea...?

If you've been to Mildenhall and seen the two big green industrial looking stacks on the near end of the runway, that was a hush house built for the SR-71. They spent millions building that thing, hauled the jet in, chained it down and cranked it up. First time they went to power it cracked the foundation, the very deep foundation, all the way through. Structural guys condemned it, and it was never used again. AAFES was storing washers and dryers in it when I was stationed there.

Serious balls on the jet troop who pushed that sled into burner

Yep. He's smart as hell and very enjoyable to listen to. I've been a subscriber to his channel for nearly a decade.

Whenever they did SR-71 engine tests in Palmdale, the entire Antelope Valley knew about it.

This is probably the best video on the J58 I've ever seen:

@2A373

One thing I've wondered about is how did the actual connections from the throttles in the F-15 link to the motors?

Was it cables and pulleys before DEEC?

How would you even service that system and the lines?

My jet still has cables and pulleys for the throttle linkage.

What actually happens from a mechanical standpoint when you advance or retract the throttles?

Throttles forward, cable connected to a lever on the motor that does what?

Do they open up the fuel flow and nozzle position simultaneously and how is that done?

I've never seen schematics for any of that.

Thanks John !
I flew on a combi twice many years ago, brings back a lot of memories.
The clamshell TR's were a welcome sight on landings.
Ft St John had the same runway length as the one at Meadowbank and it was gravel also.
Ad a hefty snow storm in to the mix and minus 40F to boot.

Still fun for a young buck like I was at the time !



LOL