The F-35 Thread

[mvsgas]

I think the point was that if you could vector lift fans thrust backwards it would act as a turbofan, theoretically increasing efficiency in slow speed flight. The question is if you can make the thrust vectoring in a manner that doesn't cause reduction in efficiency. And I suspect the theoretical increase in efficiency isn't much as the lift fan is quite small in comparison to the engine spinning it. You generally have much more bigger fan driven by a much smaller engine in highly efficient turbofan engines.

 

I think we are getting confuse here. The lift fan thrust (AFAIK) can be vector backwards and forwards by the bottom fins. Also, the F-35 engine (P&W F135) is a turbofan engine, why do you need the lift fan to change that? Are you guys confusing high bypass turbo fan like a PW4000-94 or a TF34 with a low bypass turbofan like a F100 or a F135? If you could bolt or attached the lift fan to the front of the F135 it still would not increase the engines "efficiency", it would only increase the pressure on the low pressure compressor (N1) since the engine does not have large enough bypass.

 

Here you can see the bypass ratio

https://docs.google.com/viewer?url=http%3A%2F%2Fwww.pw.utc.com%2FContent%2FF135_Engine%2Fpdf%2FB-2-4_F135_SpecsChart.pdf

 

AtqXfzHz_b8

 

Edited October 29, 2016 by mvsgas

[Buzzles]

You're all over thinking this, Pocket Sized just wrote an idea in his head without thinking it through, or not perhaps being aware of how the F-35B engine+lift fan is structured, or the differences between high and low bypass turbofans.

 

Actually going on topic though, it's going to be interesting to see how the lift fan concept plays out in terms of maintenance when compared to the traditional Harrier style over time.

Certainly a lot of a extra moving parts all over the place.

[RAZBAM_ELMO]

It's definitely a lot more simplified in terms of functionality compared to the harrier. However I really only see the VTOL function useful with the Marines and the navy possibly. But with the Air Force variant is it truly as necessary as they say?

 

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[spiddx]

However I really only see the VTOL function useful with the Marines and the navy possibly. But with the Air Force variant is it truly as necessary as they say?

 

Erm nobody says that and in fact only the Marines Variant (F-35B) has the STOVL capability.

[RAZBAM_ELMO]

Oh so they've changed it now? Wasn't the a variant equipped with it?

 

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[Rangi]

Oh so they've changed it now? Wasn't the a variant equipped with it?

 

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No, V/STOL never planned for the F-35A.

 

 

ps. your tapatalk sig is still default

[RAZBAM_ELMO]

I'm aware yeah. I haven't decided on something clever yet

 

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[Bushmanni]

I think we are getting confuse here. The lift fan thrust (AFAIK) can be vector backwards and forwards by the bottom fins. Also, the F-35 engine (P&W F135) is a turbofan engine, why do you need the lift fan to change that? Are you guys confusing high bypass turbo fan like a PW4000-94 or a TF34 with a low bypass turbofan like a F100 or a F135? If you could bolt or attached the lift fan to the front of the F135 it still would not increase the engines "efficiency", it would only increase the pressure on the low pressure compressor (N1) since the engine does not have large enough bypass.

 

The theoretical idea (ie. a hypothetical aircraft with hypothetical engine taking inspiration from F-35B) was that you could use the "lift fan" to make the low bypass engine momentarily into high bypass engine by using the extra fan to produce extra thrust in forward flight. So you would not be routing the flow through the engine or the bottom fins but have it mounted so that it can operate efficiently also in forward flight.

 

USAF is actually trying to develop an engine with variable bypass ratio to achieve better efficiency without sacrificing hight maximum thrust but this program (ADVENT, AETD) has nothing to do with VTOL.

[Phantom88]

 

Nice Illustration of F-35 Variants

 

[HiJack]

I can't see that this blog have been posted. It is words from our Norwegian test pilot, interesting read. It's all in English.

 

http://nettsteder.regjeringen.no/kampfly/2016/09/16/lack-of-perfection-does-not-mean-disaster-how-i-read-test-reports-as-a-pilot/

[Gierasimov]

Nice recording of F-35 real sim. Thought I would share as this vid is new to me:

 

https://m.youtube.com/watch?v=SbnWg4v6iHk

[Hummingbird]

F-35A side by side with Thunderbirds F-16's

 

[frixon28]

Nice pic, but yikes they dont call her Fat Amy for nothing

[Tirak]

Nice pic, but yikes they dont call her Fat Amy for nothing

 

Is that what the nickname ended up being?

[Hummingbird]

F-35: Perceived strengths & weaknesses (so far)

 

I thought it would be good with a thread specifically about the strengths & weaknesses people perceive make up the F-35 Joint Strike Fighter, both to discuss and possibly refute some of the popular opinions about the aircraft seen from both camps.

 

I would like to ask that people keep it civil and only address the argument put forth by the other party and not the person so that we can maintain a healthy debate.

 

So to kick things off the brave of you could start out by listing the strengths or weaknesses you think are going to help or plague the F-35 during its service career.

[red_coreSix]

"It's a turkey"

[Hummingbird]

"It's a turkey"

 

I think we should leave Pierre's thoughts out of this, instead give us your own ;)

[Cunctator]

Kinematic performance. The F-35 is limited to Mach 1.6. Transsonic acceleration values aren't apparently that great either. Someone compared it with the F-4. The fact that the USAF continues to modernize the F-15C and plans to operate them till 2040 strongly suggests that they don't have that much confidence in the F-35 A2A capabilities.

 

On the other side Mach 1.6 with a full weapons load is actually very good. Especially since no external pods or tanks are required. New battleships were built until aircraft carriers had proven to be the dominant assets in naval warfare. Maybe the same will happen with stealth aircraft.

 

However, if somebody builts another F-22, i.e. a supercruising, Mach 2+ airframe airplane with similarly sophisticated sensors and stealth than the F-35, than the latter would be in serious trouble. But only if these planes can be fielded in sufficient numbers to rival the numerical superiority of F-35 equipped countries.

Thus actually quite a lot of ifs. I doubt the new Chinese fighters will beat decades of experience in stealth, avionics and sensors too soon.

[lemoen]

Aircraft carriers are only a dominant asset in naval warfare if going up against a very unsophisticated enemy. Two sophisticated enemies will destroy each other's carriers in the first day with (practically) unstoppable ICBMs or whatever.

 

With the F35 I'm guessing we'll have to see. It seems to be difficult to maintain. Its small payload is not an issue for air to air warfare, you're not going to need more than 4 missiles per plane at a time anyway (or not more than once in your career in modern warfare). The issue is its A2G payload and range. Both tiny.

[The Black Swan]

Aircraft carriers are only a dominant asset in naval warfare if going up against a very unsophisticated enemy. Two sophisticated enemies will destroy each other's carriers in the first day with (practically) unstoppable ICBMs or whatever.

 

With the F35 I'm guessing we'll have to see. It seems to be difficult to maintain. Its small payload is not an issue for air to air warfare, you're not going to need more than 4 missiles per plane at a time anyway (or not more than once in your career in modern warfare). The issue is its A2G payload and range. Both tiny.

 

Usually when comparing military might nowadays you leave out nuclear ICBMs.

Mainly because if those are brought to the table then forget the carrier groups, all the nations involved just get wiped out.

[mvsgas]

Kinematic performance. The F-35 is limited to Mach 1.6. Transsonic acceleration values aren't apparently that great either. Someone compared it with the F-4. The fact that the USAF continues to modernize the F-15C and plans to operate them till 2040 strongly suggests that they don't have that much confidence in the F-35 A2A capabilities.

 

On the other side Mach 1.6 with a full weapons load is actually very good. Especially since no external pods or tanks are required. New battleships were built until aircraft carriers had proven to be the dominant assets in naval warfare. Maybe the same will happen with stealth aircraft.

 

However, if somebody builts another F-22, i.e. a supercruising, Mach 2+ airframe airplane with similarly sophisticated sensors and stealth than the F-35, than the latter would be in serious trouble. But only if these planes can be fielded in sufficient numbers to rival the numerical superiority of F-35 equipped countries.

Thus actually quite a lot of ifs. I doubt the new Chinese fighters will beat decades of experience in stealth, avionics and sensors too soon.

 

Speed above mach 1 are mostly irrelevant. Also considering most combat aircraft today can not go above mach while carrying ordnance, biggest limit is the weapons themselves.

jbgator wrote this more eloquently than I can;

http://www.f-16.net/forum/viewtopic.php?f=21&t=52428

 

But we learned a long time ago that those Mach speeds were not that important otherwise we would still be flying F-104 type jets. Going Mach 2 is only important if you are trying to run away, something most of us were loathe to do.

[lemoen]

Usually when comparing military might nowadays you leave out nuclear ICBMs.

Mainly because if those are brought to the table then forget the carrier groups, all the nations involved just get wiped out.

 

 

I didn't say nuclear ;-) Aircraft carriers are big and slow and easy targets for standoff weapons these days. Also, a sophisticated enemy will have submarines. Carriers have little hope of evading modern torpedos and seeing that the carrier group cannot hide (satellites etc), the enemy will know exactly where it is, allowing for easy submarine or long range smart weapon ambush. Carriers have become a very expensive way to move a bunch of planes around.

[GGTharos]

Kinematic performance. The F-35 is limited to Mach 1.6. Transsonic acceleration values aren't apparently that great either. Someone compared it with the F-4. The fact that the USAF continues to modernize the F-15C and plans to operate them till 2040 strongly suggests that they don't have that much confidence in the F-35 A2A capabilities.

 

That is quite incorrect. Do they lack confidence in F-16 A2A capabilities? And yet, the F-15's were there. The reason is that the F-22's and F-15's are tasked specifically with the A2A role, and are resourced and distributed to achieve coverage over the continental USA, and whatever expeditionary missions there might be.

To put it another way, all other airframes are either dual-tasked or single-role A2G, so they might not be available for all this A2A business. The F-22 and F-15 are guaranteed to be available for that specific role.

 

Thus actually quite a lot of ifs. I doubt the new Chinese fighters will beat decades of experience in stealth, avionics and sensors too soon.

 

And that's the bottom line.

[GGTharos]

Those are some very big assumptions. Autonomous weapons have fairly limited acquisition footprints, and at stand-off ranges a carrier group can sail out of them or soft-kill them. And that's assuming that you know exactly where those carrier groups are, which is not guaranteed.

The cruise missile/standoff weapon swarm IS a huge threat, but not an insurmountable one.

There are soft and hard-kill methods of dealing with it, so it still comes down to tactics.

 

Your assumption that carrier groups cannot hide is not realistic. I'm not claiming absolute stealth, but they can make targeting difficult.

 

Likewise, who's got the NAVY with all the surface-to-space weapons? Satellites aren't unreachable. They can also be blinded with lasers. Radarsats can be jammed.

 

I didn't say nuclear ;-) Aircraft carriers are big and slow and easy targets for standoff weapons these days. Also, a sophisticated enemy will have submarines. Carriers have little hope of evading modern torpedos and seeing that the carrier group cannot hide (satellites etc), the enemy will know exactly where it is, allowing for easy submarine or long range smart weapon ambush. Carriers have become a very expensive way to move a bunch of planes around.

[SkateZilla]

Im just sitting here looking at how many AIM120s they put on the block 5 like... Woooooow