Starting an early J79 vs the F119

Reacting to a question about a video claiming to show the starting sequence of an F-22 Raptor.
Watch it here: • This Is What F-22 Engi...
Comparing the sequence of events to what happens in our test cell when we test an old-school, smokey, howling early model J79 engine from an F-104 Starfighter. Designed in the 1950s, the Starfighter is faster than the F-22.
Yes it is!

[@steveshoemaker6347]

Yes l was sitting in front of smoke stack's over Nam back in the day...l am 80 years old now....Thanks AgentJayZ

[@petermuller3995]

Thank you for all your work, this is one of the best channels!

[@baileyparadis1815]

F-22 sme here... the F-22 utilizes an auxiliary power unit, a 450(ish) horsepower gas turbine engine mounted on the left side of the aircraft for emergency power, maintenance checks, and engine start. The apu itself is started by an even smaller turbine which exhausts out the side of the aircraft, which is what you see in the video. This is not a cartridge start, it uses compressed air and and fuel from the aircraft fuel system. When throttles are advanced past cutoff the apu supplies bleed air to drive the accessory gearbox which rotates the engine to its self sustaining speed.

[@AgentJayZ]

This all makes perfect sense. But where does that flame and thick smoke come from?

[@baileyparadis1815]

@@AgentJayZ That is the smaller turbine I referred to. It utilizes compressed air at several thousand psi and fuel to spin up to a design speed that provides mechanical force via a clutch to the accessory gearbox of the apu, starting it.

[@AgentJayZ]

Sure, but compressed air doesn't make rocket smoke, is all I'm sayin'

[@baileyparadis1815]

@@AgentJayZ It burns JetA/JP8 at a very rich mixture.

[@Ronke01]

Is it compressed air or nitrogen? Or is it stored hydraulic energy, such as on the F16? The JFS on the F16 will make a similar flame in rich conditions @AgentJayZ

[@mcgherkinstudios]

I didn't realise the cartridge start for the F22 was the primary means of starting the engine, I thought it was only a backup for if a start cart wasn't available. Pretty neat way of doing it. EDIT: A bit of Google-fu suggests that it's an APU called the APGS started by compressed air which is stored onboard. That's boring! Compressed air start delivers 75kW of starting power which must start the APU in 5 seconds, the APU itself creates 335kW. The whole unit weighs 120kg, manufactured by Allied Signal.

[@C-M-E]

The idea was to be able to provide on-board ability of starting at very high altitude, though to my knowledge, most of the F22s are stored in quite to opposite geographical areas.

[@mcgherkinstudios]

@@C-M-E I did wonder what sort of situation would an F22 ever be in where it didn’t have access to a start cart!

[@Colaholiker]

The smoke earned the German Starfighters with this engine the nickname "Luftverteidigungsdiesel" (air defense diesel). Keep in mind that Diesel powered ground vehicles spat out a lot more smoke back in the day than they do now, so this was a pretty accurate nickname. 😂

[@mytmousemalibu]

Fantastic stuff Jay! Thank you for what you do! I understand the pilots dislike for the smoke. Its like a big, "hey im over here" trailing a streak of black smoke as a target marker. Now rolling into AB cleans the smoke right up but of course only useful for short periods of time. I love the smoke & noise but im just an old school guy!

[@phantom1298]

Awesome smoky old J-79. Reminds my of childhood when I used to watch all the low flying Starfighters and Phantoms in Germany

[@JoeJalopy]

Your presentations really are interesting, AgentJZ, thanks.

[@joespratt413]

That’s some good ‘splain’n’ on the F22 startup!

[@michaelmurray7199]

GE J79 - 17000 pounds of thrust, smoky burn, so-so efficiency. PW F119 - 35000 pounds of thrust, clean burning, very efficient. It’s amazing what a difference 50-60 years of technological progress makes. Also, the F-104 may be faster than the F-22 in some scenarios, but the F-22 could easily fly circles around the F-104.

[@AgentJayZ]

Not saying it's a better plane, but it is way faster. Way older too.

[@horacewonghy]

Turbojet vs Turbofan

[@homefront3162]

J79's Got my Dad through Nam' in the F-4... Love that smoky biatch

[@whathasxgottodowithit3919.]

Great video as always, I remember seeing the American J79 powered Phantoms based in the U.K. flying into RAF Waddington on occasions like you said accompanied by the distinctive howl, and a smoke trail when on approach to land. The RAF RR Spey powered Phantoms based at RAF Conningsby sounded totally different, however some say they were more expensive, slower, and heavier :-) The RAF did purchase a small number of J79 powered Phantoms for use at Mount Pleasant

[@nickpiper7456]

You're such a fucking awesome KZbinr AgentJayZ. Been watching you since 2011ish, in this day and age, I feel like this is one of the safe places for many of us mans et manus types. Thanks!

[@WilliamStoneIntraNotions]

Thanks for this! Good stuff! Love your channel.

[@Mark_Ocain]

LOL...Nothing says "We're coming for ya, charlie" like a smoking J79 or two without the revised combusters. This one certainly is a howler LOL.

[@perrydiddle3698]

You make it all look so simple and easy. I know it’s not. But your expertise allows it.

[@donrideout4919]

That J 79 run up brings back memory’s run them testcell and 104 aircraft.

[@joshuad6553]

World's least efficient air-raid siren.

[@AgentJayZ]

It is designed to specifically avoid being a siren. If not it would be millions of times louder.

[@joshuad6553]

@@AgentJayZ I'd heard that was a problem with one of Whittle's first designs.

[@afterburner119]

AgentJayz, Hello my friend.!!!! I currently have a compass vector 119 that just got done running life missions at the WPB facility. You guys got it, the apu or cartridge starter is a great to have but I see the ground cart or in our case starter air (from facility) most times. We can also slow up start up at the facility depending on run programs. Not sure how much I can say so I will end there. GREAT TO SEE THE GREAT PROGRESS AT THE SHOP JAY!!!! your Florida pal.

[@AgentJayZ]

Always great to hear from you. Am I cleared to view the PDF of the starting system of the F119?

[@flyfaen1]

Late to the show, but regarding modern fighters... Most of them have a small "Jet Fuel Starter" basicly a fancy fighter slang for a small APU... BUT some fighters, especially interceptors or other types of high alertness QRAs have the option to use a cartridge-starter for even quicker starting when necessary (when even the JFS is considered too slow).

[@KevinDaheimAllein]

Regarding JFS and APU, I found the following answer of John Fanning for the F-22 in www.quora.com/What-is-the-port-under-an-F-22s-wing-that-spews-smoke-and-fire-as-it-starts-up : The F-22 is equipped with a hybrid APU (auxiliary power unit) made by Allied Signal for Boeing. Called an APGS (auxiliary power generation system), it is started by bursts of compressed air. This permits it to start far more quickly than ordinary APUs that have a typical jet engine startup procedure (because they are small turbine engines) and it permits the APGS to start and run briefly at high altitudes where the air would be too thin for a normal APU to start. APUs are designed to provide power for ground starts and A/C operation independent of ground power, and to provide a power backup source in flight. The APGS can be used to ground start the F-22 but its main emphasis is fast starting backup power for in-flight emergencies. The compressed air and jet fuel fast start looks and sounds a lot like the old propellant cartridge based Coffman “shotgun starter” systems used on WW II era piston aircraft, but the APGS is a true gas turbine engine APU that packs a lot of power output (450 HP) into a pretty small package (220 pounds) and unlike a typical APU, it can be producing that power in 5 seconds and start at high altitude if need be. The Allied Signal G-250 APU that forms the core of the APGS system is regarded as being one of the most compact and highest power density APUs in the industry. Incidentally, if the two stored compressed air charges fail to start the APGS, the compressed air can be restored by tapping hydraulic pressure bleed-down from the F22’s hydraulic system which might be good for two attempts if, in the absence of external hydraulic power, the hydraulic pressure was full. And if *that* fails, there’s actually a hand pump in the cockpit that can pump up the system. The physical effort required to pump up the system manually for one restart attempt has been compared by pilots to doing 150 push ups, but it would permit the startup of the F-22 even if every stored energy source, with the exception of jet fuel, on the aircraft were exhausted.

[@bt_the_yank6234]

Wow love the howl. So authentic. If only the f104 in war thunder sounded like this and not a vacuum cleaner

[@AgentJayZ]

In my limited experience, all aviation related video games are so sadly lacking in the engine sounds, that I don't want to play them. Maybe I'm part of a "special interest" group.

[@bt_the_yank6234]

@@AgentJayZ haha yeah I understand that.

[@alta9dena]

Interesting start-up procedure for the J-47's in a B-47: kzbin.info/www/bejne/eZbQZ6CZa8apnbs (watch from time 17:56)

[@planekrazy1795]

Marvellous, exactly how a Starfighter should sound.

[@Chris9rr]

Always loved the howl of this engine. But I do understand that it can be down side for the pilots plus the black smoke. Though it is easier to tell that the engine is in after burner when the black smoke goes away. Smoke equals cruise. No smoke equals after burner on.

[@babaksadidi4419]

how does nozzle section expand relative to thrust?

[@christinadaly7743]

I watched a British squadron of Electric Lightening's at Spangdahlem AFB in 1974 use cartridge starts , " Smoke city " , those Over/Under engines got pretty hot before take off , my guess is piling those engines just made more wing area .

[@grahamj9101]

The engines weren't "over/under": they were staggered one behind the other.

[@Mark_Ocain]

I laugh when I think of the British Electric Canberra bomber. It had cartridge starts to spin the Avons enough to start. They were sooty as! When they were showcased in the US for the first st time, one American ground crew mistook that smoke for a start fire and dumped a crap-load of foam on the aircraft, and crew LOL

[@JimmyD_C172]

Stunning! I would love on for my man-cave along with a Yankee Candle that smells like kerosene. Thank you for sharing AgentJayZ...

[@cvasirocket1401]

@AgentJayZ can you feel the difference between a howling screecher and it's younger variants? I am not referring to the sound as it's deafening irregardless of the engine type variant when one is so close to any such running engines .

[@AgentJayZ]

They are both louder than it is possible to describe. Body shaking.

[@maxeisenstadt1459]

In videos of the F-4 and F-104 the J-79 always has a very particular whine to it at idle, is this also caused by the nozzle?

[@AgentJayZ]

It's that metal-shredding sound coming from the compressor. It's most noticeable when observed from the front of the aircraft/engine.

[@GarageSupra]

That smoke is cool, it really gives a visual sense of how much air these pups move. Haven't seen that before 👌 Also what is with the howl being different at different RPM? Like it seems to be a similar tone but comes and goes at different RPM or is that just the camera mic struggling with the harmonics/volume of the engine?

[@AgentJayZ]

I tried to explain it in the video.

[@christinadaly7743]

Any idea of how much air is sucked into the nozzle between the convergent and divergent area at high throttle , what would be a relative percent of air to exhaust ? It's amazing that the tail pipe of the new GMC diesel trucks have the same CD outlet , but there's no whistle sound . The OEM engineers must have known about the J79 nozzle

[@AgentJayZ]

In the description of nozzle function, there is no mention of how much air is drawn in, but it is clearly stated that the jet propulsion nozzle is actually formed by the air that is drawn between the primary and secondary flaps, as they are called. So the inner nozzle is extended by air flowing through the exterior nozzle, and the actual nozzle is made of air. I think that is super genius high tech, eh?

[@SuperSecretSquirell]

The reason for the tailpipe design is to draw cool ambient air into the tip and keep it (and the exhaust gases) cool because during active regeneration the exhaust temps get really high and can cause fires if parked near something flammable (pretty common if parked in tall dry grass).

[@LateNightHacks]

1:27 I'm hyperventilating, so what's the deadline for that job? Monday?

[@sufysprojects2689]

Hi! I have a question! Why is a high bypass turbofan more efficient than a lower bipass version? Is use for airliners? I think it has to do with accelerating a bigger mass of air al lower speed, but I don't know.... Thanks! Greetings from Italy :)

[@ASJC27]

You have it right. At airline speeds (Mach ~0.8) a high bypass engine has a better propulsive efficiency due to a slower moving exhaust. It also has a better overall efficiency, but that is not necessarily always the case - depends on speed. For example, the Concorde's Olympus engines had an overall efficiency that is only matched now by the latest turbofans. An optimal overall efficiency is achieved when the exhaust speed is about twice as fast as the aircraft, so a high bypass turbofan is great for high subsonic speeds, but even ignoring the added installation drag it is a poor choice for supersonic flight.

[@sufysprojects2689]

@@ASJC27 thank you very much!! The concept that I want to understand is: why, for an airliner, is it more efficient to accelerate a huge amount of air al low speed compared to accelerating a small mass of air at a much higher speed? I can't get my head around that

[@ASJC27]

@@sufysprojects2689 The propulsive efficiency of a jet improves the closer the exhaust jet speed is to the flight speed, so accelerating more air a little bit gives higher propulsive efficiency. For this reason, slow aircraft will benefit from the very slow moving air of a turboprop, jet airliners benefit from faster, but still fairly slow high bypass turbofan. For aircraft designed for transonic speeds (fighters) a low bypass turbofan is better, for high supersonic aircraft (e.g. Concorde) pure turbojets are better, and for even faster speeds a ramjet is needed.

[@sufysprojects2689]

@@ASJC27 thank you very much!!!

[@mikecowen6507]

Jay, haven't seen much of the test cell since its overhaul. What happened to the "old yeller" start cart? Also, as you may have access to the once secret numbers, did the difference in combustor design have any notable change in SFC? Just thinking the low smoke design might result in getting more heat from the fuel vs. soot. Thanks!

[@AgentJayZ]

The low smoke upgrade is slightly less fuel efficient. Same power, a bit more fuel consumption.

[@Pub01]

I got 99 problems but AgentJayZ ain't one.

[@vaderdudenator1]

Hydraulic start? How do you get enough speed out of hydraulics to start a turbine? Aggressive gearing up?

[@AgentJayZ]

You only need a couple thousand rpm to get a turbine engine started. Hydraulic motors can do that no problem. Also, a turbine by itself can not be "started". A turbine is part of a turbine engine, and the difference is important.

[@zapfanzapfan]

Did you get a new startcart? I remember it being yellow.

[@jreid641]

I wondered the same thing. Definitely not the one they usually use.

[@FastFerry1975]

What a sound, very typical! But.. any idea where the howling originates from?

[@AgentJayZ]

As explained in the video, it comes from the short-petal nozzle. It must act like some kinda big whistle, eh?

[@DougHanchard]

There are very few military cartridge start turbine aircraft still in service. The most famous being the B-52. The Phantom II F-4 believe it or not, is still flying in limited military service around the world. Early B-707s & DC-8s that I flew used retrofitted compressed air bottles if no ground start Air APU was available.

[@BrorAppelsin]

Is the jet nozzle also the reason why Avro Vulcans had that distincrive howl?

[@planekrazy1795]

The Vulcan Howl is caused by the air intake. A single scoop that splits into two on each side. Very simply it's like blowing across a glass milk bottle. Hope that answers or makes sense to you.

[@charlottejet4338]

@@planekrazy1795 You are correct. I have a Vulcan to play with and I've slid down those intakes. That was a very pleasant afternoon 😉

[@tommy13t]

What is the black smoke from? What’s causing it?

[@leeharris3061]

Incomplete combustion ..he said in the vid the later models of that engine had different combustor liners leading to less smoke

[@tommy13t]

@@leeharris3061 yeah, I posted question before end of video. Just didn’t think they would let this go through as a final design before production. But I guess that was before the EPA

[@AgentJayZ]

The EPA? This was a new design for a fighter jet engine that was 50% more powerful than the competition at the time. Do you know what fighter jets are used for? Do you know how much the designers and users of fighter jets care about pollution? Don't be that commenter. You know the one...

[@C-M-E]

So a curious question on new vs old technology: After reviewing quite of few of the giant-sized industrial gas generator engines, why do most of them use combustor cans versus annular combustors? Even the really new GE ones use cans. I haven't been able to find an efficiency versus cost reason, or simplicity of manufacture even though they are anything but. Graham, I hope you're lurking around! =)

[@AgentJayZ]

The new engines use a system called DLE, for dry low emissions. It lengthens the combustion pathway without lengthening the engine. Industrial engines are much more efficient and less polluting than aircraft engines, partially because their design is not constrained by size and weight.

[@C-M-E]

@@AgentJayZ Hmm, very interesting. Looks like a breadcrumb for more reading. Thank you for the reply, sir!

[@grahamj9101]

Yes, I've just come across your question - and yes, the very large, 'heavyweight' industrial gas turbines almost invariably had multiple combustors, long before DLE was ever thought of. Can you imagine developing and testing a single, large annular combustor for one of those machines? It would require a massive compressor plant to produce enough air - and think about the fuel costs, too. Beyond that, there are also mechanical and structural issues to consider. The walls of the combustor would have to increase in thickness, unless they were supported by an external structure of some form, which would be an interesting design challenge, either way. Multiple combustors are altogether a more practicable solution.

[@C-M-E]

@@grahamj9101 Damn, once again I'm feeling rather foolish once you highlighted certain things that should have been obvious. Makes total sense.

[@perrydiddle3698]

Have you ever experienced a catastrophic failure during testing?

[@charlottejet4338]

Wow! Can anybody imagine living next door to Jet City? 😂 That is how the last dinasour must have sounded in its final death throws following the asteroid impact millions of years ago! Fricking awesome! 🇬🇧🇨🇦🇬🇧🇨🇦

[@AgentJayZ]

I think a planet-shaking asteroid impact would be bajillion times this loud, making any other sound meaningless, and destroying any sound sensing instrument or organ world wide. Stay tuned for the follow-up, afterburning video.

[@charlottejet4338]

@@AgentJayZ Thank you AgentJayZ. I can't wait to see and hear it. If I ever visit Canada, I'll have to make a pilgrimage to Jet Wash Alley. I'll add it to the bucket list. Maybe I'll return home with a rock and keep it on my desk as a paperweight 😀 I'm looking forward to the next installment. 🇬🇧🇨🇦🇬🇧🇨🇦

[@Twister8700]

What type of plane is this engine going to be used for?

[@AgentJayZ]

Starfighter

[@Twister8700]

@@AgentJayZ Thank you

[@keithcarpenter5254]

@@AgentJayZ weren't they in the phantom too?

[@Agavarc]

20:10 How dare you ;-) Starter cart sounds beautiful ^_^

[@steveingalls6798]

Looks like you need to work on reducing your carbon footprint 😁

[@justarandom404]

Hi, I would like to buy a sweatshirt with the Jet City logo. However I can't seem to find a link in your video. I see some knock off stuff, I want to make sure I support your channel, can you provide a link for merch in your video descriptions?

[@AgentJayZ]

The Stuff at Redbubble is authentic. Search for AgentJayZ

[@justarandom404]

@@AgentJayZ There are no hoodies or sweatshirts available on your merch site! I will grab a t shirt, but would love to see some variety

[@justarandom404]

Okay I see them now. Thx!

[@dalefuller4233]

Allied Signal G-250 APU

[@brianhiles8164]

Why does the exhaust nozzle (at 03:00) have a "spinner" center cone design, like that of an inlet orifice? Such a design has _higher_ aerodynamic drag in the transsonic regime than for a truncated cone. The only reason I can think, is that it was because of manufacturing efficiencies: having a common design for both ends, but I am unaware of this for the ubiquitous Avro Canada Chinook or Iroquois (correct?) but I can find no graphics that make this plain. I know you have not confused it for an inlet section, because it plainly has refractory foil wrapped around it. Would you kindly address this mini-mystery, _AgentJayZ?_

[@AgentJayZ]

The output of the turbine is a ring shape, and the jet nozzle has a circular cross section. The centerbody of the tail cone is their to minimize turbulence, and maintain cross sectional area during the transition from one shape to another at speed.

[@grahamj9101]

There's no mystery: where do you get the idea that it results in higher aerodynamic drag? Most engines of that era (and most since) have a conical centrebody fairing in the exhaust unit downstream of the turbine. There is actually some diffusion in the exhaust unit before the acceleration through the final nozzle.

[@brianhiles8164]

@@grahamj9101 : Everybody knows the transonic regime is the aerodynamic velocity range with the highest drag. This is the range of the velocity of hot gas efflux of this engine, as is indeed typical of engines of this period and thrust. In regard to transonic aerodynamics, the design of internal and external bodies to minimize drag can be counterintuitive. Sometimes the smooth and "swoopy" has higher drag than a sharp bend or truncation. For example, in the early 1960s when Bristol Engine Company was designing the vectored-thrust Pegasus engine to power what was to become Hawker Siddeley's Harrier "jump jet," the first "obvious" smooth design for the rear fork (to the rear nozzles) was found to have _more_ drag (that is, less _pressure recovery_ ratio) than a later design which implemented simple "harsh" small-radius bends and sharp folds. In general, conical centerbody fairings used in inlets are distinguishable from the one in outlets, but for this engine in question, my question was to resolve a matter of longstanding curiosity: This early low-power turbojet, despite being designed for efflux to _not_ be (fully!) in the supersonic regime, nevertheless had an afterbody which is _identical_ to an inlet. One would expect it to be at least a _little_ different in fundamental design -- thus my original question, the reasoning of which is appropriately expressed there.

[@ASJC27]

@@brianhiles8164 "Everybody knows the transonic regime is the aerodynamic velocity range with the highest drag." I'm an aerospace engineer working in aerodynamic design and I don't know that. The transonic region is where drag _coefficients_ are at their highest, but the drag itself keeps rising through it - it doesn't fall after the transonic regime, only the coefficient does. As for the centerbody, the efflux coming out of the jet nozzle may be transonic or supersonic after it's accelerated in the nozzle, but the flow at the centerbody section and entering the nozzle is decidedly subsonic, and even slower than it is going through the turbine. The centerbody is there, as AgentJayZ said, to smoothly transition from the annular cross-section at the turbine to a round cross section at the nozzle.

[@brianhiles8164]

@@ASJC27 : As for the first paragraph, I know all this. It is difficult to communicate efficiently in a non-technical forum, because one may easily obfuscate the matter with technical "exegesis". BTW, drag, meaning coefficient of drag, is of secondary applicability to _pressure recovery,_ really, because we are talking about internal aerodynamics -- a concept that you know I know, because I used that term. Your statement about drag versus coefficient of drag ignores the matter that my question involved (and still involves) the "counterintuitive" nature of design considerations for optimal _pressure recovery_ in the transonic (and supersonic) regime. As for every succeeding clause, including the whole of the second paragraph, it is either a restatement of mine, or not applicable, or only contextually valid; indeed, it gives me no confidence that you have carefully read my original query. I even alluded to the matter in the comment you respond to, as well as giving an _explicit example_ that supported and explicated it. As for the third paragraph, you essentially support _AgentJayZ's_ reply, but I must say, although I was impressed by his quick reply, and indeed thanked him for his time and effort by having given it a Like, I must say he completely misconstrued my question as asked, to give no answer at all. I said nothing of this, but I see that I now have to. While I appreciate your contribution, as I did his, there can be no credibility without giving me a sense that you even read and understood the OQ, to give an appropriate answer.

[@leeharris3061]

Hey i spy a new white start cart..looks good to me

[@mickellis8747]

Ah, the old Air research GTSU. Qantas scrapped 6 of those about 12 months ago. Sent them to the recyclers !!!!

[@BillyNoMates1974]

Interesting video clip on the jet engine starter. Makes me wonder what type of engines can reliably be started and immediately go to full speed. A petrol engine wouldn't suffer that abuse for long.. mind you there must be enough lawn mowers that are ran hard

[@AgentJayZ]

Got a video that talks a bit about that, called Cool Your Jets.

[@BillyNoMates1974]

@@AgentJayZ thanks I will check that out

[@perrydiddle3698]

I know it’s off topic, but I can’t help myself. You said ~ 1/3 of excess air is the low bypass air. You say it’s such a low bypass engine. Because it needs the power to “supercruise”. What is supercruise, and wouldn’t a... let me ask, is the engine a turbofan? But, wouldn’t more bypass air give more thrust (and power)? Does the “rocket solid fuel starter only have one starting attempt, and then it’s spent? And, this was only for the starting turbine, right? And, I’m assuming the two main engines have the normal electric spark ignition for startup, correct? I know I asked a lot of questions, so, I don’t expect you to answer them all, if any. Thanks in advance.😉

[@ASJC27]

Supercruise is the ability to cruise at supersonic speeds without the use of afterburner. A higher bypass ratio for the same amount of total air mass flow will result in less thrust, but potentially better TSFC (but that's not a given - depends on other factors like flight speed). A higher bypass ratio with the same amount of core flow will usually lead to higher thrust.

[@AgentJayZ]

That's not what I said, and your questions are far too broad to answer in a comment box. Except for: solid rocket motors are indeed use once and discard.

[@perrydiddle3698]

I find it interesting that you, being up in Canada, reference Empirical sizes and degrees Fahrenheit, and not metric...any comment on that? Am I wrong?

[@AgentJayZ]

We work on old engine designs, and the entire aviation industry is heavily influenced by the USA, where there is still a stubborn refusal to use the far more rational metric system.

[@Buff_Dave_Oprtr]

Wasn't the j79 used in a cruise missile?

[@williamkillingsworth2619]

F-4 Phantom was its main use. I do not believe I was used in a cruise missile.

[@AgentJayZ]

Used in the Regulus cruise missile, and in quite a few significant aircraft.

[@Buff_Dave_Oprtr]

@@AgentJayZ I thought so,thanks. Great video,as usual.

[@hksp]

this is gud, more smok, n short nozzle

[@lwilton]

My, that thing is the mother of all banshees, isn't it? It must make them feel insecure because they aren't loud enough. It's almost a shame that I stayed to the end and heard your explanation of the smoke. I was going to say that it seemed like it was running a little rich, probably due to that cold northern air causing the oxygen to precipitate out.

[@WarblesOnALot]

G'day, Ah, Oxygen doesn't "precipitate out of the air" regardless of how far North or South you go...; inside a really expensive Cryogenic Chamber you will be able to liquify the Oxygen and the Nitrogen, and the Carbon Dioxide....; but it'll take a Nation State or a Multinational Corporation to pay the Refrigerator's Power Bill. Dig out an old Sci-Fi Short Story titled, "A Bucket Of Air..." to get the first "Word Picture" of the phenomenon which I ever encountered, back in the 1960s. Such is Life, Have a good one... Stay safe. ;-p Ciao !

[@wernerswanepoel9276]

This is pure porn!! 💙

[@AgentJayZ]

Loads of engine test vids on my channel... some with afterburners!

[@longsweep1]

Wish You would be my teacher.

[@buddycat81]

i think you need to draw a picture...

[@publicmail2]

Remember the average intelligence of a person, and remember that 50% are dumber...

[@WarblesOnALot]

G'day, A more nuanced view..., is that 60% of Humanity have an Intelligence Quotient Test Score ("IQ") of between 95 & 105, with 20% of the population being either smarter or sillier than that chunk of "Normality". All Advertising & Marketing is aimed squarely at that 60% of "Normality" scoring between 95 & 105..., on the pragmatic grounds that anybody with an IQ under 95 is too silly to be able to follow any complex arguement or chain of Logic, and anybody smarter than 105 is too clever to be swayed by any specious and/or disingenuous feats of Marketeering.... Either way, the Dullards and the Smarties represent a pair of Minority Groups, neither of them are capable of personally hand-making any of the Consumer-Products on which their Lifestyle depends - so both groups are forced to take their Choices from what's available on the Shelves - and all the Advertising is contrived to manipulate the more malleable muddled Classes... By Law, nobody with an IQ under 70 is permitted to vote..., and anybody who scores 130 or over is ranked as being a "Genius". To gain entry to MENSA (a Club for lonely & socially-isolated Genii...) requires one to be able to reliably & repeatedly produce an IQ Score of 140, or over Theoretically the maximum possible IQ score is 200, when one is allowed the usual amount of Time in which to take the Test...; and the way to measure the score of anybody who achieves 100% Correct Answers in less than that time than that..., is to retest them with half the usual Time Limit, and then to double their resulting score... Thus, people like Barry Jones (Australia's Minister for Science in the Hawke Labor Government of the 1980s) is said to have an IQ Score of 275 - out of a possible 200 (!). Such is Life, Have a good one... Stay safe. ;-p Ciao !

[@rossblake101]

Wow...

[@eltoro6688]

Video cut was likely due to "SECURITY CONCERNS"!!!!!!!!!