@jdowney429 Basic principles and construction is the same. More modern engines have two or three rotor systems--high and low pressure, so that the fan operates at a lower optimized to generate thrust, and the compressor operates at a high speed optimized to generate power in the form of gas for the low pressure turbine.
@AgentJayZ Thanks. Out of curiosity, why is engine oil used? Is there a reason it was kept separate from the aircraft hydraulic system? The only thing I ever worked on was T700 engines on Apache helicopters. It's really cool to know about other engines and their operating principles, especially something as historic as the J79.
@discofishing There is a dividing line between engine and airframe that aims to simplify as much as possible the whole arrangement.
The aircraft hydraulics are powerd by an engine-driven pump, but the engine hydraulics are not part of that system. The engine oil pump may be used to power the engine hydraulics, or they may be powered by yet another external hydraulic pump.
Thank you very much for making these videos. This is by far the most interesting youtube channel I've yet found.
I have a question about afterburner liners: Is their green tint due to oxidation (perhaps due to the chromium in the alloy), or is it some sort of ceramic coating?
@anoncritic The liner of the afterburner duct is ceramic coated, and it is usually white or light grey. Sometimes the coating is green.. I don't know the reason.
Awsome video. I think the J-79 is one of the coolest Jetengines ever - I`m a big Starfighter fan so I just have to like it. Really nice of you doing a overlook of this engine - thanks for sharing :-)
It's hard to imagine where people came up with these ideas to make something that is so amazing and unconventional compared to what was around before the Jet Engine. Thanks for sharing this information, I enjoyed learning more about the way these things work.
@TheMrbum Well, there was quite a long development before the jet engine came into existence. The first gas turbines go back to around 1900, and the first modern steam turbines were built in 1884, so engineers had a long time to experiment and work out the principles and techniques that would make the jet engine possible.
Great video! What I don't understand about these engines is that most of the parts are such thin sheet metal. They look fragile. With the pressures and thrusts involved, I don't get where the structural strength comes from. Only the bearing housings look strong.
@svenp Hey, you're looking at a video, and I can't capture all of it. If you worked with the stuff, you'd see everything is made like the finest workmanship possible. What looks like sheet metal is mostly thin machined parts from super-tough metal alloy.
Also, turbine engines don't have pressures and shock loads like piston engines trying to contain explosions.
If car engines were made like this, they'd last for millions of Km.
@AgentJayZ I get what you're saying regarding pressures. But still, something has to transmit the 18,000lbs of thrust to the airframe. That outside skin doesn't seem like it's made for that. I'm guessing that the rotor is designed to carry the axial load to the bearing housings which transmit it to the airframe?
@svenp Sounds good! As far as exactly where the force/thrust is generated and exactly how much pushes on which part... that's a mixture of engineering and black magic.
@svenp Axial load is transmitted exactly as you describe, from rotor through a thrust bearing to a main frame that's bolted directly to the air frame.
@AgentJayZ@svenp A lot of the static parts, especially vanes on the older engines are sheet metal. The J85, for example, was designed as a cruise missile engine, and was intended to be "disposable." With upgrades, they are still flying in T-38s to this day.
Are the compressor blades seized due to being in the elements to long - or are they mounted that way into the disk? Trying to figure out as it doesn't seem to make sense to have loose turbine blades and fixed compressor blades.
Very cool! I like the musical compressor blades. A question...are the "nozzles" in the turbine section like the stators in the compressor? There are no stators in the turbine, right? But between each disc, there is a set of nozzles to direct the flow at the best AOA to hit the next disc? Is that right? Also, I remember reading something about one of the two sets of exhaust nozzles being mechanically adjusted, while the second adjusts itself according to the pressure...is that true?
@justforever96 The turbine nozzles are located upstream of their respective turbine stage, while a compressor stator is located downstream of its respective stage, otherwise the two components are similar.
Stators decelerate air coming off a compresor stage, raising its pressure, and direct it at the next.
Turbine nozzles accelerate exhaust gases, lowering their pressure, and direct them towards turbine.
@IWMYB61 The direction of the airflow through the engine acts like a large wind blowing down on the top of this imaginary wing. The effects of this wind are less severe as the wing speeds up. But the wind gets stronger as the wings "above" it move faster.
When I try to match the behaviour of the variable vanes in the J79 to my intuition , I can't. It does not seem to make sense.
@IWMYB61 This is a complicated question, which I will partially answer with a simplified explanation.
Think of a compressor blade as a small wing flying through the airstream. The angle of attack of this wing depends on its own speed ( engine rpm ), and on any velocity the air it is flying through might have.
The VIGVs and the VSVs work to make sure this resultant angle of attack is kept within a range of values at which the wing will not stall.
Worked on the GE J-79-10 used in the F4 -J Phantom from 1973-75 aboard USS Independence CV-62. We ran a lot of these on the test cell during two Mediterranian cruises. I kept several technical books on the -10. I've never forgotten the sound as these were turning up. It cost me some hearing loss but what the heck. Like having a battle scar; I'd never complain. An unequalled experience.
Cool cut-away! We have an extra J75 engine that we want to put on display in front of our test cell, but only have the cases. It would be great if we can get some old internal parts and make something like this!
@77bubba00 You have a J75? or just the cases? Do you have any leads to any complete J75's? .... I need one - lets make a deal. S&S Turbines has tremendous reserves of parts...
That was one overly complicated engine! I had to work on one in tech school and it seemed that almost everything had double locknuts and safety wire! What a nightmare! LOL
Man this video is amazing. I am a jet engine enthusiast. I love how simply complex they are and this video helped me better understand a lot about turbines.
@AgentJayZ don't worry I'm am way ahead of you on that one. I get excited to see ":A Closer Look" in the titles. I hope to build my own turbine for a college project soon by using a old car turbo. Now I'm thinking of the best flame holder or flame tube design that I could make with out major tools.
Wow, I don't know why it took me so long to find your channel. I am fascinated by jet engines, since I am an AF brat and my dad worked on J-79s. This is the best tour of a jets internals I have ever seen. Just curious though, from another vid, you said most of the blades you were removing from an engine were being tossed out. Do you sell them for the scrap value? I'd love to obtain a few blades from a J-79 as desk ornaments.
I love your videos!!! I've always been amazed at jet engines and have wanted to learn more about how they work. Your videos are by far the most informative I've seen. Thanks!!
@COD5252 Well, you're getting into design philosophy of engines, which determines the engineering solutions, which then determines the way the things are actually built... which is where my experience is, to be honest.
Fantastic Jay! Thanks for the tour! Hows the torch ignited and stay lit jay? I presume its burning liquid fuel? Somthing i saw on another video, but what would cause some random sparks to come from the jetpipe?
@mytmousemalibu The torch ignitor has its own fuel nozzle and ignition plug, inside the housing.
Random sparks could be a result of a slight rub of the turbine in the case ( minor ), or it could be pieces of an overheated turbine blade breaking off ( major)
@AgentJayZ Ah ok! kinda neat! I saw in comments of another video of F-104's at night so i could see the torch igniter in action, real neat how it illuminates the jet pipe at night! That same video, one of the Starfighters spit a few sparks out the back. But it was just off idle so prolly some blade contact then. Unless the torch caused it because it was on? Thanks Jay!
@cheetawolf The compressor is designed to operate efficiently at maximum power and engine RPM. Without the variable inlet guide vanes and variable stators, it would not be able to get up to that speed from idle.
The variable vanes direct the airflow towards their stages at the appropriate angle for the rotor rpm, airflow velocity, and the rotor blade angle of attack.
For a more detailed answer, read "the jet engine" by Rolls Royce", an excellent introductory text.
How many combustion cans are there in a passenger plane engine? ...say trent 600
NinjaPr00 5 days ago
@NinjaPr00 One
AgentJayZ 5 days ago
and fuel ionizer?
99XM 1 week ago
@99XM No such thing
AgentJayZ 1 week ago
@jdowney429 Basic principles and construction is the same. More modern engines have two or three rotor systems--high and low pressure, so that the fan operates at a lower optimized to generate thrust, and the compressor operates at a high speed optimized to generate power in the form of gas for the low pressure turbine.
andyjwagner 1 week ago
Very good explanation !
i1p2p3o4c5a6m7p9o9 2 weeks ago
thanks for the vid. im going for my o&p soon. i found this vid helpfull. thumbs up.
princejaa 2 weeks ago
Cool
TheWarbirdPhoenix 1 month ago
what actuates all the mechanical components on this particular engine? Oil, hydraulics, bleed air, fuel?
discofishing 1 month ago
@discofishing A separate hydraulic pump using engine oil does most of the work.
AgentJayZ 1 month ago
@AgentJayZ Thanks. Out of curiosity, why is engine oil used? Is there a reason it was kept separate from the aircraft hydraulic system? The only thing I ever worked on was T700 engines on Apache helicopters. It's really cool to know about other engines and their operating principles, especially something as historic as the J79.
discofishing 1 month ago
@discofishing There is a dividing line between engine and airframe that aims to simplify as much as possible the whole arrangement.
The aircraft hydraulics are powerd by an engine-driven pump, but the engine hydraulics are not part of that system. The engine oil pump may be used to power the engine hydraulics, or they may be powered by yet another external hydraulic pump.
AgentJayZ 1 month ago
Thank you very much for making these videos. This is by far the most interesting youtube channel I've yet found.
I have a question about afterburner liners: Is their green tint due to oxidation (perhaps due to the chromium in the alloy), or is it some sort of ceramic coating?
anoncritic 2 months ago
@anoncritic The liner of the afterburner duct is ceramic coated, and it is usually white or light grey. Sometimes the coating is green.. I don't know the reason.
AgentJayZ 1 month ago
Having bought Kurt ?Schreckling?'s "how to build a turbine" in my teens and read it cover to cover over and over, I love your videos.
The noise of the blades is great, maybe you could work out a simple tune to play on them. :)
lexichronicle2 2 months ago
@lexichronicle2 There's a YT entity named Darkjurney, who has made some music with sounds from another blade video of mine.
It's called Ghost Turbine.
AgentJayZ 1 week ago
@AgentJayZ Ha! Just had a listen, really interesting. I love Ghost in the Shell too.
lexichronicle2 1 week ago
Thanks so much for sharing.
jgiguain 2 months ago
I got more out of this 6 minute video than a ton of crappy vids/animations on engines.
Good job, keep it up!
memadmax69 2 months ago
The best video I have ever seen. Best Channel...
Good Job...
cprashanthreddy 2 months ago
you are smart dude.
ashazaria 2 months ago
Thanks for upload and the explain. Very interesting!
Skyisnotalimit 3 months ago
Awsome video. I think the J-79 is one of the coolest Jetengines ever - I`m a big Starfighter fan so I just have to like it. Really nice of you doing a overlook of this engine - thanks for sharing :-)
HIGGI6 3 months ago
you guys have a j-57?
tubelib 3 months ago
@tubelib Not at the moment, but we can get you one.
AgentJayZ 3 months ago 7
It's hard to imagine where people came up with these ideas to make something that is so amazing and unconventional compared to what was around before the Jet Engine. Thanks for sharing this information, I enjoyed learning more about the way these things work.
TheMrbum 3 months ago
@TheMrbum Well, there was quite a long development before the jet engine came into existence. The first gas turbines go back to around 1900, and the first modern steam turbines were built in 1884, so engineers had a long time to experiment and work out the principles and techniques that would make the jet engine possible.
colindhowell 1 month ago
@colindhowell I wonder if they ever realized when they started the first experiments what would eventually become of the original concept.
TheMrbum 1 month ago
Where is anti─iceing section?
moistp00 3 months ago
@moistp00 This is an engine core, with noe external accessories attached. Anti-icing system is all external air piping.
AgentJayZ 3 months ago
nice video.
the engine seems so yuckily complex. doesn't feel like a clean design.
I'd probably also place the starter motor in the nose cone instead of a long transmission
DanFrederiksen 3 months ago
Great video! What I don't understand about these engines is that most of the parts are such thin sheet metal. They look fragile. With the pressures and thrusts involved, I don't get where the structural strength comes from. Only the bearing housings look strong.
svenp 4 months ago
@svenp Hey, you're looking at a video, and I can't capture all of it. If you worked with the stuff, you'd see everything is made like the finest workmanship possible. What looks like sheet metal is mostly thin machined parts from super-tough metal alloy.
Also, turbine engines don't have pressures and shock loads like piston engines trying to contain explosions.
If car engines were made like this, they'd last for millions of Km.
AgentJayZ 4 months ago
@AgentJayZ I get what you're saying regarding pressures. But still, something has to transmit the 18,000lbs of thrust to the airframe. That outside skin doesn't seem like it's made for that. I'm guessing that the rotor is designed to carry the axial load to the bearing housings which transmit it to the airframe?
svenp 4 months ago
@svenp Sounds good! As far as exactly where the force/thrust is generated and exactly how much pushes on which part... that's a mixture of engineering and black magic.
AgentJayZ 4 months ago
@svenp Axial load is transmitted exactly as you describe, from rotor through a thrust bearing to a main frame that's bolted directly to the air frame.
andyjwagner 1 week ago
@AgentJayZ @svenp A lot of the static parts, especially vanes on the older engines are sheet metal. The J85, for example, was designed as a cruise missile engine, and was intended to be "disposable." With upgrades, they are still flying in T-38s to this day.
andyjwagner 1 week ago
interesting video.
however i have a question...
why do you have a turbine engien in your backyard?
krobi94 4 months ago
@krobi94 It's the front yard...
AgentJayZ 4 months ago 7
@AgentJayZ
oh that explains alot,thanks
:D
krobi94 4 months ago
@AgentJayZ love the answer :-)
marcducati 3 months ago
Are the compressor blades seized due to being in the elements to long - or are they mounted that way into the disk? Trying to figure out as it doesn't seem to make sense to have loose turbine blades and fixed compressor blades.
tyroneorourke 5 months ago
@tyroneorourke Seized from dirt and corrosion
AgentJayZ 4 months ago
"Now you're an expert on the J79 Turbojet engine."
Since we've established I'm an expert, are you hiring?
ph13rwun 5 months ago
@ph13rwun We dont really hire...it's more a process of: Engulf, Indoctrinate, Render, Reconstitute, Release !
It is often uncomfortable...
AgentJayZ 5 months ago
@AgentJayZ I have no fear. I am accustomed to pain.
ph13rwun 5 months ago
Thankyou for sharing it with us !!
This video was very informative, i learned a lot
zero00tolerance 5 months ago
preserve this dude!!
bingoblu 5 months ago
This type also powered the Lockheed U-2 I believe.
agwhitaker 5 months ago
@agwhitaker Yes...
AgentJayZ 5 months ago
Very cool! I like the musical compressor blades. A question...are the "nozzles" in the turbine section like the stators in the compressor? There are no stators in the turbine, right? But between each disc, there is a set of nozzles to direct the flow at the best AOA to hit the next disc? Is that right? Also, I remember reading something about one of the two sets of exhaust nozzles being mechanically adjusted, while the second adjusts itself according to the pressure...is that true?
justforever96 5 months ago
@justforever96 The turbine nozzles are located upstream of their respective turbine stage, while a compressor stator is located downstream of its respective stage, otherwise the two components are similar.
Stators decelerate air coming off a compresor stage, raising its pressure, and direct it at the next.
Turbine nozzles accelerate exhaust gases, lowering their pressure, and direct them towards turbine.
AgentJayZ 5 months ago
@IWMYB61 The direction of the airflow through the engine acts like a large wind blowing down on the top of this imaginary wing. The effects of this wind are less severe as the wing speeds up. But the wind gets stronger as the wings "above" it move faster.
When I try to match the behaviour of the variable vanes in the J79 to my intuition , I can't. It does not seem to make sense.
However , it works very well.
Like I said, it's complicated.
AgentJayZ 8 months ago
@IWMYB61 This is a complicated question, which I will partially answer with a simplified explanation.
Think of a compressor blade as a small wing flying through the airstream. The angle of attack of this wing depends on its own speed ( engine rpm ), and on any velocity the air it is flying through might have.
The VIGVs and the VSVs work to make sure this resultant angle of attack is kept within a range of values at which the wing will not stall.
AgentJayZ 8 months ago
LOL i still have some of these mixing air holes at home.
robin6512 8 months ago
That was thumbs uppy experience
fuck4freei 8 months ago
I believe these engines were used in F4 Phantom II jets. Also F104 Starfighters.
supramanz 9 months ago
@supramanz Your beliefs are correct... I believe...
AgentJayZ 9 months ago
Would be interesting to see a song played from a jet engine haha.
warmachine000 9 months ago
that´s tottally crazy dude !!!
thambs up
marcosaba360 9 months ago
Worked on the GE J-79-10 used in the F4 -J Phantom from 1973-75 aboard USS Independence CV-62. We ran a lot of these on the test cell during two Mediterranian cruises. I kept several technical books on the -10. I've never forgotten the sound as these were turning up. It cost me some hearing loss but what the heck. Like having a battle scar; I'd never complain. An unequalled experience.
JonMichael001 10 months ago
Excellent video. Thanks for sharing it!
banga1969 10 months ago
Cool cut-away! We have an extra J75 engine that we want to put on display in front of our test cell, but only have the cases. It would be great if we can get some old internal parts and make something like this!
77bubba00 10 months ago
@77bubba00 You have a J75? or just the cases? Do you have any leads to any complete J75's? .... I need one - lets make a deal. S&S Turbines has tremendous reserves of parts...
AgentJayZ 10 months ago
@AgentJayZ ... Our company overhauls them. I think we sell them too, but they aren't cheap! :)
77bubba00 10 months ago
That was one overly complicated engine! I had to work on one in tech school and it seemed that almost everything had double locknuts and safety wire! What a nightmare! LOL
77bubba00 10 months ago
Man this video is amazing. I am a jet engine enthusiast. I love how simply complex they are and this video helped me better understand a lot about turbines.
mii3000 11 months ago
@mii3000 I hope you like my other videos...
AgentJayZ 11 months ago
@AgentJayZ don't worry I'm am way ahead of you on that one. I get excited to see ":A Closer Look" in the titles. I hope to build my own turbine for a college project soon by using a old car turbo. Now I'm thinking of the best flame holder or flame tube design that I could make with out major tools.
mii3000 11 months ago
Wow, I don't know why it took me so long to find your channel. I am fascinated by jet engines, since I am an AF brat and my dad worked on J-79s. This is the best tour of a jets internals I have ever seen. Just curious though, from another vid, you said most of the blades you were removing from an engine were being tossed out. Do you sell them for the scrap value? I'd love to obtain a few blades from a J-79 as desk ornaments.
indoorherbivore 11 months ago
Ohh, pretty engine >:)
MrTpengineer 11 months ago
wat is the fuel nozels?
51zelao 11 months ago
@51zelao If you mean where are the fuel nozzles, at 1:30 you are looking right at one.
If you mean what are fuel nozzles, well they are fuel nozzles.
AgentJayZ 11 months ago
Nice video. Explaines the J79 very clearly. Thanks for recording and uploading.
DrBPhD 1 year ago
awesome, and well explained!
AXHEJAZ 1 year ago
I love your videos!!! I've always been amazed at jet engines and have wanted to learn more about how they work. Your videos are by far the most informative I've seen. Thanks!!
boulder667 1 year ago
very informative video!
Parkinson9999 1 year ago
What if there are 2 combustion chambers instead of 9-10 chambers,plz reply me
COD5252 1 year ago
@COD5252 You're opening a bit of a can of worms here.
Technically this engine has one combustor outer case ("chamber"), with ten liners in it.
Liners are often called cans, and cans makes you think of chambers.
Older engines did have separate combustor cases ( "chambers") of various numbers.
Newer engines have one case and one annular liner.
I don't know of any engine that has two liners, or that has two separate outer cases.
Running out of characters now. Hope that helps.
AgentJayZ 1 year ago
@AgentJayZ i got it thx btw what u meant by opening can of worms lol
COD5252 1 year ago
@COD5252 Well, you're getting into design philosophy of engines, which determines the engineering solutions, which then determines the way the things are actually built... which is where my experience is, to be honest.
AgentJayZ 1 year ago
@AgentJayZ im going to design a more fuel effecient jet engine its gunna blow peoples minds dont worry airline prices will be the thing of the past
fatqwert200 1 year ago
I love your video's Jay... very very cool, you get/got really wicked toys, Dude.
kvnnagel 1 year ago
Fantastic Jay! Thanks for the tour! Hows the torch ignited and stay lit jay? I presume its burning liquid fuel? Somthing i saw on another video, but what would cause some random sparks to come from the jetpipe?
mytmousemalibu 1 year ago
@mytmousemalibu The torch ignitor has its own fuel nozzle and ignition plug, inside the housing.
Random sparks could be a result of a slight rub of the turbine in the case ( minor ), or it could be pieces of an overheated turbine blade breaking off ( major)
AgentJayZ 1 year ago
@AgentJayZ Ah ok! kinda neat! I saw in comments of another video of F-104's at night so i could see the torch igniter in action, real neat how it illuminates the jet pipe at night! That same video, one of the Starfighters spit a few sparks out the back. But it was just off idle so prolly some blade contact then. Unless the torch caused it because it was on? Thanks Jay!
mytmousemalibu 1 year ago
Great video as always! Thanks for showing the torch ignitor that lights up the afterburner fuel.
Have a good rest of the weekend!
outspwq28 1 year ago
Excellent vid!! This is top notch turbine engine education for free! Great stuff man.
Xx69roadrunnerxX 1 year ago
exelent video..AGENT.information very important
EDUARDOERD 1 year ago
Very interesting and informative. Thanks!
saxonlight 1 year ago
im just wondering, whats the point ov the variable blades on the intake rotor and stators?
cheetawolf 1 year ago
@cheetawolf The compressor is designed to operate efficiently at maximum power and engine RPM. Without the variable inlet guide vanes and variable stators, it would not be able to get up to that speed from idle.
The variable vanes direct the airflow towards their stages at the appropriate angle for the rotor rpm, airflow velocity, and the rotor blade angle of attack.
For a more detailed answer, read "the jet engine" by Rolls Royce", an excellent introductory text.
AgentJayZ 1 year ago
Excellent, thnx for post.
traveler08a 1 year ago
Once again, a very interesting video (not only for aviation students ;) ) , tnx m8!
Musti087 1 year ago