Nice presentation Jay and I would have to go with your second summation regarding the corrugations. heat expansion will cause a smooth chamber to warp and deform permanently where the corrugations allow the shape to return to its previous dimensions without any undesired change in shape or heat distortion effect The Skunk works team used this theory on the Blackbirds outer skin for all the above reasons.
Great stuff Jay. I always thought the "big bumps"were to stop the hot gasses spiraling like a plughole. I'm thinking of the baffles they put into the F1 rocket engine for that same reason. Really interesting thank you for the content. Greg, New Zealand.
I'm now retired but in my last job I machined loads of afterburner "flame-holding" gutters. We seldom knew which engine they were for but they may have been Spey, Rb199, ??? Considering the environment in which they operate the mounting brackets were machined to ludicrously fine tolerances. They were made of very hard steel too.
Hi John. The basic shapes were pressed whilst glowing hot. Then little square holes were machined for the mounting brackets which were TIG welded in. The brackets were then slotted using a triple gang mill to fine tolerance. I used to do this last op.
I am no engineer, but I have done construction since 1984. My opinion is that the waves in the liner are mainly for strength, and like Jay said the multitude of holes are to allow a layer of cooling air to keep the fire from melting the liner.
Thats crazy, the first video I watched on this channel was the J79 nozzel test, and this is the second video I clicked on. Crazy that they are related with such a large time span in between.
All your videos are pretty awesome so thank you. I'm sure you know this but GE calls those opening louvers and the limits of serviceabily of cracks are pretty loose. Pretty much as long as there's no risk of a a louver falling off you are good in most areas. I appreciate the relation you made of an "accordian or corragated cardboard". I'll use that at my work for the new kids coming in. 👍🏼
The afterburner doesn't generate separate thrust, it just boosts the velocity of the exhaust gas already coming out the back. (Not a jet engine mechanic, so there may be some fine detail I missed, but that's my understanding) Quoth wikipedia: "The afterburner increases thrust primarily by accelerating the exhaust gas to a higher velocity." it's backed up by footnote 6 on the "afterburner" page, if you want to see the math.
Thrust is generated by the acceleration of exhaust gases as they pass through the final nozzle. So you could say the reaction forces act on everything ahead of the nozzle, which is every part of the engine.
That is a FUN QUESTION with probably a proper complex answer that might need an engine designer to explain it in detail. The engine designer from RR did touch on some aspects of this and Jay does talk about it also.
Each bag is based on units, depending on the size of the bag. We still preserve the T56 with 28 bags using tech "Manual to the SPI standards. "method 50". You can reuse those bags by microwaving them, but we've never done that. We just buy new 100%
Oh, it's an old timey thing. Sort of interpreted as "darn it" or "aw, shucks". So, you knew it all along. It was probably a new thing to our grand parents.
@@AgentJayZ Thanks for info, I’m just a layman but I was just wondering if those slots were used to create a Venturi effect from the fast moving jet air in the center of the engine? Great videos…
@@givenfirstnamefamilyfirstn3935, you haven’t heard many, have you, if that’s the loudest you’ve heard? Loudest I have heard was earlier this year, at RIAT, when the F35 was in the hover.
@@johnnunn8688 Have you heard a Buccaneer close at low level then? It had/has no jet pipes or afterburners/reheat, the exhaust is straight into the exterior air and is exceptionally loud even though it has low bypass turbofans.
I don't know of any test we've done where I wasn't shocked by the noise level. LM1500, LM2500, J79, J47, Orenda 10, Orenda 14, RR Avon, RR Spey, RR Olympus, Wright J65, and even the RR Tyne when it gets "on the pipe". It's all roaring thunder...
@@givenfirstnamefamilyfirstn3935 , the Phantom Spey has reheat added to the noise. Trust me, the Phantom Spey is louder, much louder. The F35 is louder than that, by an order of magnitude.
I have an afterburner question. This concerns a TF-30. As a crew chief on F-111 aircraft and engine run qualified we had 5 "zones" of afterburner. You knew which "zone" you were in by the position of the exhaust nozzles as you advanced the throttle through all 5 "zones". Are there any other engines with afterburners that have "zones" or is that something specific to a TF-30?
The terminology might change, but I think all modern afterburners work this way. The J-79s we work on have two separate manifolds for carrying fuel to the spraybars on the early models, and four on the later models. Each spraybar has four sectors, each supplied by one of the manifolds. Each manifold is supplied by the AB fuel pump through a valve that opens at a specific pressure, increasing from the first to the last. The afterburner is progressive, but the fuel pressure to each little orifice in the spraybars is maintained above a minimum, so no dribbling occurs... Here's a vid i made about sprabars ruclips.net/video/IHVnWVgzUE8/видео.html Actual fun fact: the manual states that in order to bench test the afterburner fuel pump, an electric motor of at least 175 Hp is required to drive it.
When you put (compressor) right next to turbine, that's usually a way of indicating the two words mean the same thing. Nothing could be further from the truth. In function the two are exactly the opposite. I have a vid called what makes a turbine turn, which will help you, I think.
@@AgentJayZ So to clarify, it's because of the power shaft extending out the rear of the gas duct that the exhaust flow is turned 90° and thus requires an "exhaust pipe".
We have heavily modified a Solar Saturn exhaust manifold for this purpose. I honestly have never seen a real Tyne exhaust duct, either for aircraft or for the marine version...
G'day Jay Zed... If ye REALLY Give a shite...., Then, Why not put Thy Holiday Pay Towards Wire-Brushing, Priming, And Painting ALL of Them there Tubularised Engines.... (?). Just(ifably ?) Wonderin'... Stay Safe ! ;-p Ciao !
You mean the rusty engine storage cans? They are not mine. Why don't you paint the rusty old vehicles you see in a storage yard on someone else's property. Don't you care?
@@AgentJayZ Oopsie, My mistake... I thought that you Cared about the Engines Inside them...(?) ; And that Therefore, Even as a source of Available Spare Parts - it could be Worthwhile for you to Ensure that the Engine's Storage Cans Fail to Corrode...(?). But, I suppose...., By the time those Containers rust Through You Will be too old and Feeble to Give a Shit... Eh ? And, Anyway, Global Warming will have Killed the EcoGnomie Neccessary To fund any Cashed-up Yuppie Playing with Fossil-Burning Turbojet Hobbies and Playthings... So, Yeah... You're 100% Correct. All those Time-Expired Corroding old Engines Are ultimately WORTHLESS Scrap Metal which Some Silly Idiot Paid To have made. Such is life. Have a good one... Stay safe. ;-p Ciao !
It's kind of astounding to realize just how much taxpayer money and engineering sweat went into developing and building those, and now they just sit there.
They had a service life, its not like you can use it at home. If they are going to waste alot of the money anyway might as well make advanced jets what if we need them and we dont have them.
Well, it's one of the most successful turbine engines ever made. I think the total number produced is just over 18 thousand. One of the reasons we will never run out of parts for it in our lifetime.
What a fun trip to the back lot !!! Thanks for taking us to places where few of us would ever normally get to see.
I am so lucky to work where I do... I feel it's my obligation to share it !
Nice presentation Jay and I would have to go with your second summation regarding the corrugations.
heat expansion will cause a smooth chamber to warp and deform permanently where the corrugations allow the shape to return to its previous dimensions without any undesired change in shape or heat distortion effect
The Skunk works team used this theory on the Blackbirds outer skin for all the above reasons.
Great stuff Jay. I always thought the "big bumps"were to stop the hot gasses spiraling like a plughole. I'm thinking of the baffles they put into the F1 rocket engine for that same reason.
Really interesting thank you for the content. Greg, New Zealand.
RUclips really sucks. I haven't see one of your videos show up on my feed for months and I've been subbed for years.
I'm now retired but in my last job I machined loads of afterburner "flame-holding" gutters. We seldom knew which engine they were for but they may have been Spey, Rb199, ??? Considering the environment in which they operate the mounting brackets were machined to ludicrously fine tolerances. They were made of very hard steel too.
Gutters ‘machined’, really?
Hi John. The basic shapes were pressed whilst glowing hot. Then little square holes were machined for the mounting brackets which were TIG welded in. The brackets were then slotted using a triple gang mill to fine tolerance. I used to do this last op.
Thanks for the mini-update on the Iroquois, I was wondering what became of it.
I am no engineer, but I have done construction since 1984. My opinion is that the waves in the liner are mainly for strength, and like Jay said the multitude of holes are to allow a layer of cooling air to keep the fire from melting the liner.
You are correct
Like corrigated iron for roofing and others
Thanks for the update on the Iroquois
i would think the curves also increases surface area of/for cooling air,,i like these "field trips"
Thats crazy, the first video I watched on this channel was the J79 nozzel test, and this is the second video I clicked on. Crazy that they are related with such a large time span in between.
Some philanthropic soul needs to fund you some more indoor dry storage for all those engine containers.
All your videos are pretty awesome so thank you. I'm sure you know this but GE calls those opening louvers and the limits of serviceabily of cracks are pretty loose. Pretty much as long as there's no risk of a a louver falling off you are good in most areas. I appreciate the relation you made of an "accordian or corragated cardboard". I'll use that at my work for the new kids coming in. 👍🏼
Send a hat, and I'll wear it and mention your institution in a video.
Can anyone tell me which surfaces of the jet engine does thrust generated by the afterburner act on?
The afterburner doesn't generate separate thrust, it just boosts the velocity of the exhaust gas already coming out the back. (Not a jet engine mechanic, so there may be some fine detail I missed, but that's my understanding) Quoth wikipedia: "The afterburner increases thrust primarily by accelerating the exhaust gas to a higher velocity." it's backed up by footnote 6 on the "afterburner" page, if you want to see the math.
Thrust is generated by the acceleration of exhaust gases as they pass through the final nozzle.
So you could say the reaction forces act on everything ahead of the nozzle, which is every part of the engine.
The thrust would act on the entire engine. Thrust goes one way engine goes the other.
That is a FUN QUESTION with probably a proper complex answer that might need an engine designer to explain it in detail. The engine designer from RR did touch on some aspects of this and Jay does talk about it also.
I have a video called "where does thrust act?" and a search feature on my channel page.
Are the corrugations not just feed channels for the cheese-grater air vents?
Their purpose is the subject of this video.
7:29 What are those two white bags laying in the bottom of the engine for?
They are filled with sillica gel to absorb humidity. Usually they are lots of them when the engine is in its crate.
That's dessicant. It dries the air in a sealed container. A container for the Iroquois would need about 50 of those bags.
Those two are just litter.
Each bag is based on units, depending on the size of the bag. We still preserve the T56 with 28 bags using tech "Manual to the SPI standards. "method 50". You can reuse those bags by microwaving them, but we've never done that. We just buy new 100%
It's much safer to renew the dessicant by heating in a standard oven to 275F for 24 hours...
I hear from pilots from Aircrew Interviews
They didn't like the change from J-79's to RR Spey
In the F-4 phantoms, retired 1993 from RAF I believe.
I'm so out of touch. What is that hand gesture at 1:13? I like it and want to start using it. Keep em coming!
Oh, it's an old timey thing. Sort of interpreted as "darn it" or "aw, shucks". So, you knew it all along. It was probably a new thing to our grand parents.
Wouldn’t the slots draw in cooling air since fast moving air will have less pressure and in turn draw in the cooler air from behind the slots?
The fast moving air is inside the jet pipe. The cooling air is at a slightly higher pressure.
@@AgentJayZ Thanks for info, I’m just a layman but I was just wondering if those slots were used to create a Venturi effect from the fast moving jet air in the center of the engine? Great videos…
Reheated Spey from a Phantom, the Buccaneer Spey had no reheat.
The Buccaneer is the loudest plane I ever heard.
@@givenfirstnamefamilyfirstn3935, you haven’t heard many, have you, if that’s the loudest you’ve heard? Loudest I have heard was earlier this year, at RIAT, when the F35 was in the hover.
@@johnnunn8688 Have you heard a Buccaneer close at low level then? It had/has no jet pipes or afterburners/reheat, the exhaust is straight into the exterior air and is exceptionally loud even though it has low bypass turbofans.
I don't know of any test we've done where I wasn't shocked by the noise level.
LM1500, LM2500, J79, J47, Orenda 10, Orenda 14, RR Avon, RR Spey, RR Olympus, Wright J65, and even the RR Tyne when it gets "on the pipe".
It's all roaring thunder...
@@givenfirstnamefamilyfirstn3935 , the Phantom Spey has reheat added to the noise. Trust me, the Phantom Spey is louder, much louder. The F35 is louder than that, by an order of magnitude.
I have an afterburner question. This concerns a TF-30. As a crew chief on F-111 aircraft and engine run qualified we had 5 "zones" of afterburner. You knew which "zone" you were in by the position of the exhaust nozzles as you advanced the throttle through all 5 "zones". Are there any other engines with afterburners that have "zones" or is that something specific to a TF-30?
The terminology might change, but I think all modern afterburners work this way. The J-79s we work on have two separate manifolds for carrying fuel to the spraybars on the early models, and four on the later models. Each spraybar has four sectors, each supplied by one of the manifolds. Each manifold is supplied by the AB fuel pump through a valve that opens at a specific pressure, increasing from the first to the last.
The afterburner is progressive, but the fuel pressure to each little orifice in the spraybars is maintained above a minimum, so no dribbling occurs...
Here's a vid i made about sprabars ruclips.net/video/IHVnWVgzUE8/видео.html
Actual fun fact: the manual states that in order to bench test the afterburner fuel pump, an electric motor of at least 175 Hp is required to drive it.
@@AgentJayZ That is a mighty powerful electric motor, man, oh-man.
Yeah... we test the AB fuel pump by hitting full AB in an engine test. It's impressive, as you can see in many of my vids.
Have you ever been tempted to sit on one of the turbines while running in the test cell? Thanks for the close up.
Turbine case temperature at idle will be over 700F, and close to double that at full power. Never thought of sitting there.
@@AgentJayZ Some insulation in between and you'll be right.
@@AgentJayZ Do you ever choke the intake of a turbine (compressor) to simulate a high altitude environment, or is it just a sea level static test?
When you put (compressor) right next to turbine, that's usually a way of indicating the two words mean the same thing. Nothing could be further from the truth. In function the two are exactly the opposite.
I have a vid called what makes a turbine turn, which will help you, I think.
@@AgentJayZ I think he's just using the word turbine to mean "jet engine" then specifying compressor?
Hi Jay, what is that ducting on the scaffolding @ 10:00?
I think that's the exhaust duct that they use when testing power turbines.
It's the exhaust duct we use for the Tyne. It has an integral power turbine, so doug is very close to being correct.
@@AgentJayZ So to clarify, it's because of the power shaft extending out the rear of the gas duct that the exhaust flow is turned 90° and thus requires an "exhaust pipe".
We have heavily modified a Solar Saturn exhaust manifold for this purpose. I honestly have never seen a real Tyne exhaust duct, either for aircraft or for the marine version...
@@AgentJayZ Yes! That inverted teardrop/banjo shape is exactly what I visualized. Thanks!
Greetings Jay
everything gets bumpled wrinkled and old
❤
Buccaneers didnt have reheat, only the Phantoms.
😊
Can I make the turbine rotate 1500 rpm to generate 220 volt electrical power?
You might want to watch my vid called Power Turbines and What They Do.
I like crinkle chips for this reason
1st and cool burners
Turdeau will probably forbid you from rebuilding that Iroquois for fear that it might foment some Canadian national pride.
I try to discourage any descent into politics.
@@AgentJayZ You're right, it is jet channel.
G'day
Jay Zed...
If ye
REALLY
Give a shite....,
Then,
Why not put
Thy
Holiday Pay
Towards
Wire-Brushing,
Priming,
And
Painting
ALL of
Them there
Tubularised
Engines....
(?).
Just(ifably ?)
Wonderin'...
Stay Safe !
;-p
Ciao !
You mean the rusty engine storage cans?
They are not mine.
Why don't you paint the rusty old vehicles you see in a storage yard on someone else's property.
Don't you care?
@@AgentJayZ
Oopsie,
My mistake...
I thought that you
Cared about the
Engines
Inside them...(?) ;
And that
Therefore,
Even as a source of
Available
Spare Parts - it could be
Worthwhile for you to
Ensure that the Engine's
Storage Cans
Fail to
Corrode...(?).
But, I suppose....,
By the time those Containers rust
Through
You
Will be too old and
Feeble to
Give a
Shit...
Eh ?
And,
Anyway,
Global Warming will have
Killed the
EcoGnomie
Neccessary
To fund any
Cashed-up Yuppie
Playing with Fossil-Burning
Turbojet
Hobbies and
Playthings...
So,
Yeah...
You're 100%
Correct.
All those
Time-Expired
Corroding old Engines
Are ultimately
WORTHLESS
Scrap Metal which
Some Silly Idiot
Paid
To have made.
Such is life.
Have a good one...
Stay safe.
;-p
Ciao !
It's kind of astounding to realize just how much taxpayer money and engineering sweat went into developing and building those, and now they just sit there.
They had a service life, its not like you can use it at home. If they are going to waste alot of the money anyway might as well make advanced jets what if we need them and we dont have them.
For perspective, the price paid by the government for a J79 in the late sixties was about 100K US.
How many of those could you buy for one F 135?
@@AgentJayZ I dare say one "might" be able to buy "all of them"? But that's a wild guess.
@@AgentJayZ Yeah, the numbers I've seen were $625k US in 1960 each for a J79, which is about $6.5M today.
Well, it's one of the most successful turbine engines ever made. I think the total number produced is just over 18 thousand. One of the reasons we will never run out of parts for it in our lifetime.