Engines used in different fighters

[Beast]

Panavia Tornado's bucket-style thrust reversers in action :

Related link(s).

That looks like a troll gif.

 

[mil-avia]

Klimov VK-1 A (left) and Klimov RD-45 FA (right) engines used in Iℓ-28 bomber and in MiG-15 fighter respectively :

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Related link(s).

 

[mil-avia]

50 Amazing Aircraft Engines

 

[randomradio]

@gambit

I needed a foreign pilot's perspective on this topic, if you could oblige.

If the F-16 is modified with an engine that could generate full military power between 30,000-50,000 feet, how much of an advantage would it give you over a regular F-16 that you used to fly?

 

[gambit]

If the F-16 is modified with an engine that could generate full military power between 30,000-50,000 feet, how much of an advantage...

So just for those who do not understand...

In jet engine parlance, what is 'military power' or simply 'mil-power' is %100 throttle forward WITHOUT afterburner. To enter afterburner, the throttle must be physically lifted over a detent on the throttle assembly in the cockpit. Flying in constant mil-power is NOT encouraged at any altitude, but sometimes it must be done, like after take off.

Let us take an F-15 or F-16 with full ground strike loadout. That mean for both jets, two external fuel tanks along with assorted bombs and missiles. Take off will require full AB, then once the jet attained sufficient airspeed for altitude gain, the engines can be out of AB but must still remain in mil-power for a certain amount of time until airspeed is enough to sustain stable cruise, then the engines will be throttled back to usually around %80-ish. At higher altitude where air is less dense, the engines can be moved back but the percentage level depends on the loadout. An air-air loadout will be less 'draggy' at any altitude and to cruise at that altitude will have a lower throttle setting, which means longer sortie duration and more fuel available for maneuvers if needed.

The issue here is air density. Lower air density means less combustion which means less power. Lower air density also means lower drag for any configuration. The combination of the two is why some aircraft designs performs better/less than others at certain altitude in all performance aspects such as climb rate, turn rate, etc. So the goal for the jet engine designer is to have %100 efficiency the combustion process regardless of air density, which we know is not possible.

Afterburner is using UNPROCESSED fuel.

In the combustion process, in jets or cars, the fuel is atomized, meaning to make as small droplets as possible to achieve maximum burn. The AB simply streams raw fuel into the hot exhaust and let the barely controlled explosion provides additional thrust. This is why AB is fuel wasteful, but necessary.

Lower air density means that in order to achieve the same thrust at higher air density, more fuel must be processed, as in the air-fuel ratio. Remember, we are still in the PROCESSED fuel stages, not AB. At ground level, the car uses a constant 14.7:1 ratio, meaning 14.7 parts of fuel to one part of air. With this fixed ratio, most cars have decreasing performance at higher elevations.

An aircraft operates at variable altitudes, so it make sense to allow variable fuel mixtures.

Another factor is the air inlet or intake opening size. The F-16 have two models where the Block 30 have the 'big mouth' inlet, but essentially, inlet opening is a constant. The SR-71 is a different class so will not be considered here.

Without AB, in order to achieve the same mil-power at 10,000 ft, at 30,000 ft, and at 50,00 ft, since inlet size is fixed, that mean the fuel-air ratio must be variable. The higher the fuel-air ratio, the more fuel consumption, which leads to the same results as in using AB, just less of them.

So the real question is whether a jet fighter, F-15 or F-16 or whoever, is able to maintain the same mil-power at varying altitudes in order to achieve its missions. Eventually, at increasing altitudes, the fuel-air ratio will become so rich, as in so lopsided towards fuel instead of air, that we ended up with something like the SR-71.

The fighter with the engine that can produce the most constant power output will have many advantages over its less capable opponents. Advantages like better sustained turn and climb rate, immediate throttle response, or longer mission duration.

 

[randomradio]

The fighter with the engine that can produce the most constant power output will have many advantages over its less capable opponents. Advantages like better sustained turn and climb rate, immediate throttle response, or longer mission duration.

Thanks. I wanted this confirmed.

How much of a difference do you believe is possible between an aircraft equipped with the new engine and one with the old engine? 10%? 20%?

 

[Gomig-21]

If the F-16 is modified with an engine that could generate full military power between 30,000-50,000 feet, how much of an advantage would it give you over a regular F-16 that you used to fly?

What do you mean by "modified"? If you're asking specifically about the F-16, then ATM there are really only 2 - 3 options between the General Electric F110-GE-129 and the Pratt & Whitney F100-PW-229 on almost every single flying F-16 out there with the exception of the UAE's block 60s which are powered by the more powerful General Electric F110-GE-132. Almost 2/3 of the 1,500 or so USAF F-16s are powered by the F110-GE-129 and the other 500 or so by the PW F100-229.

So there really are limitations to your hypothetical with basically those 3 -- but mostly 2 -- engines.

Also, just to be clear (and I'm not sure why @gambit doesn't clarify this with you) but he was a technician for the F-111 and F-16 and not a pilot of those 2 aircraft. I'm guessing Mr. gambit was working on the F-16 prior to the AFE program when the GE engine was introduced (or maybe not), and so his experience was more likely with the PW although his duties might not have been engine mechanics. Go back to post #18 and that member "Chogy" was an F-15C pilot. Too bad he doesn't participate here anymore.

Another issue with this "modifying" question/concept is that the F-16 (more likely the same applies with other jet-specific engines) is that both, the PW and GE have specific engine mounts. Essentially a C-channel that runs through the top of the engine which slides onto a built-in rail in the upper compartment of the engine bay and is pinned in the front with 2 bolts. Aside from other piping connections and electrical connections/harnesses, those are the two primary mounting elements of the F-16 engines which differ in many of the other, non-US jets. That's probably why he answered the question the way he did without giving any specifics on any kind of power generated at any specific altitudes. A modified engine needs to be one of those two (or 3) and those two are at their peak as of this date, besides the F110-GE-132 which as far as I know, is not part of the current Viper upgrade being offered. The latter having a maximum thrust of 32,500 lbs as compared to an average of 29,500 on the other two. An additional 3K lbs probably makes a big difference in your question and why the UAE asked for those in their block 60's. They are the only F-16s currently using that engine.

So the answer is really limited to those 3 engines and there are no modification to be made to them at this stage without introducing a completely new engine specifically for that aircraft.

 

[randomradio]

What do you mean by "modified"? If you're asking specifically about the F-16, then ATM there are really only 2 - 3 options between the General Electric F110-GE-129 and the Pratt & Whitney F100-PW-229 on almost every single flying F-16 out there with the exception of the UAE's block 60s which are powered by the more powerful General Electric F110-GE-132. Almost 2/3 of the 1,500 or so USAF F-16s are powered by the F110-GE-129 and the other 500 or so by the PW F100-229.

So there really are limitations to your hypothetical with basically those 3 -- but mostly 2 -- engines.

Also, just to be clear (and I'm not sure why @gambit doesn't clarify this with you) but he was a technician for the F-111 and F-16 and not a pilot of those 2 aircraft. I'm guessing Mr. gambit was working on the F-16 prior to the AFE program when the GE engine was introduced (or maybe not), and so his experience was more likely with the PW although his duties might not have been engine mechanics. Go back to post #18 and that member "Chogy" was an F-15C pilot. Too bad he doesn't participate here anymore.

Another issue with this "modifying" question/concept is that the F-16 (more likely the same applies with other jet-specific engines) is that both, the PW and GE have specific engine mounts. Essentially a C-channel that runs through the top of the engine which slides onto a built-in rail in the upper compartment of the engine bay and is pinned in the front with 2 bolts. Aside from other piping connections and electrical connections/harnesses, those are the two primary mounting elements of the F-16 engines which differ in many of the other, non-US jets. That's probably why he answered the question the way he did without giving any specifics on any kind of power generated at any specific altitudes. A modified engine needs to be one of those two (or 3) and those two are at their peak as of this date, besides the F110-GE-132 which as far as I know, is not part of the current Viper upgrade being offered. The latter having a maximum thrust of 32,500 lbs as compared to an average of 29,500 on the other two. An additional 3K lbs probably makes a big difference in your question and why the UAE asked for those in their block 60's. They are the only F-16s currently using that engine.

So the answer is really limited to those 3 engines and there are no modification to be made to them at this stage without introducing a completely new engine specifically for that aircraft.

My question was speculative. I wanted his perspective based on his experience on the F-16 with an engine that can generate the same thrust at sea level and high altitude.

AFAIK, he was an F-111 back seat driver and F-16 driver.

 

[Gomig-21]

AFAIK, he was an F-111 back seat driver and F-16 driver.

Nope. He was a crew personnel for both those aircraft, not a pilot and I find it very weird how he doesn't clarify that for those who assume it?! He likes to keep it in the dark for some reason, but for those of us who've known him on forums since 2008, know very well when he came out and identified himself as a crew member and even spoke about his one (what the USAF calls) a one-time "fam-ride" or "incentive flight" where they take a member of the crew up on a flight as a reward for their services etc. And that is where he got to fly the F-16 for a few minutes and that is the extent of it. This was all from his own words on a thread in a now defunct forum and so it's nothing I'm making up. Nor does it minimize what he did by any means. A career in the USAF is excellent no matter what your duty is/was and his shared knowledge is exceptional. But to not clarify the exact extent of his duty and to play along as if he was a pilot is extremely disingenuous in my opinion.

Anyway, are you perma-banned or temporarily banned? Anyone know? I hope my explanation of the way the engines are limited to only 3 variants was helpful to your question of capable "modifications" on them.