# Curious about upgrading F18 F series



## Torch (Apr 10, 2008)

Since the F version of the F18 has a bigger airframe etc. Would it be compatible to install the F-22s F119 35000 thrust engine compared to the 18's F414-Ge-400's 20 to 22k thrust engines? Compared to the new fighters coming out it seems like the F18F is lacking in the speed/supercruise capabilities and since it looks like the Navy is going to keep the Fs around I was just curious about the performance aspects or if it's even feasible.


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## Matt308 (Apr 10, 2008)

While possible, the changes would introduce major structural and fuel modifications that would be cost prohibitive. Not sure you would ever realize the efficiency and performance gains with that airframe anyway.


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## SoD Stitch (Apr 10, 2008)

Matt pretty much said it. The sfc is probably about the same for both engines, but IIRC the F-119 has a much larger fan diameter than the F-414 and, therefore, a higher mass airflow rate; I'm assuming it would take a major redesign of the intakes and airframe. I also believe range would suffer; the Super Bug already has short legs, I think the F-119's would make that range even shorter.


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## Torch (Apr 10, 2008)

True plus the f-35 coming would negate the attempt to modify the F-18. Just seems that compared to the Soviet jets that have been around the US fighters just don't have those big engines. Probably alot to do with reliability also.


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## SoD Stitch (Apr 12, 2008)

Torch said:


> True plus the f-35 coming would negate the attempt to modify the F-18. Just seems that compared to the Soviet jets that have been around the US fighters just don't have those big engines. Probably alot to do with reliability also.



More to do with efficiency; Russian/Soviet gas turbines tend to be less efficient than comparable Western engines. The Tumansky engines on the MiG-25/31 series of aircraft are HUGE, almost the size of a commercial turbofan, in order to generate the required thrust; a Western engine of comparable power would probably be about 2/3-3/4 the size of it's Russian counterpart. My guess is this is due to metallurgical reasons; I believe our high-temp refining processes are more developed.


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## Ramirezzz (Apr 12, 2008)

SoD Stitch said:


> More to do with efficiency; Russian/Soviet gas turbines tend to be less efficient than comparable Western engines. The Tumansky engines on the MiG-25/31 series of aircraft are HUGE,
> 
> 
> almost the size of a commercial turbofan, in order to generate the required thrust; a Western engine of comparable power would probably be about 2/3-3/4 the size of it's Russian counterpart. My guess is this is due to metallurgical reasons; I believe our high-temp refining processes are more developed.


You're probably right regarding the Tumanski engines of the MiG-25 - the titanium wasn't extensvely used in that engine so its high performace was achieved by the cost of a great weight.
Now look at the MiG-31 engine - it generates about 152 kN of AB thrust, almost the same amount of thrust is generated by the SR-71 engine - PW -J58. And the J-58 is 200 kG heavier as the Soloviev D-30.
This engine is actually the very same type of engines which were used in some soviet civil airliners, only with an afterburner fitted, so you're quite correct when talking about its size of a commercial turbofan)))


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## Milos Sijacki (Apr 13, 2008)

Although the F-18 is a good, multipurpose fighter, I don't see why would the airforce, with the introduction of new F-22 and F-35 fighters already on the way, spend money and resources upgrading.


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