F-35B Grounded

It's 2500 over its entire lifespan of 30-40 years.

 

Take the F-15C, there were some 700 made (IIRC, don't quote me on the numbers), but it wasn't as if there was a force of 700 F-15C's, they were basically turning over fatigued airframes etc.

 

New is, not always but most of the time, better then old. And for that reason I do support F-35 program. But for god sake, why 2500 of it? Why do we have to borrow money from China and Saudi Arabia to build 2500 F-35's? I would say, we would be just fine with maybe 500. And then have a slew of much cheaper F-16, F-18 with latest sensors technology.

 

This whole F-35 program, along with some other insane and unnecessary military programs, will make some people enormously rich, while putting the entire country on a brink of bankruptcy. I don't want to work the rest of my life to pay for unnecessary number of F-35's, when the job can be done with F-16. Just check the debt clock, 16.5 trillion and counting ....

You're making assumptions based on useless data. I could tell you that an F-15 can hold an 11g turn, sustained. Does this data point do anything for you?

 

3rd gen manoeuvrability:

So you're ignoring the graph I posted, like everything else. Airliner wings have some elements designed to reduce wave drag but only where they don't compromise the reduction of lift drag. Look at the wing profile of an airliner, it's clearly not designed primarily for the reduction of wave drag.

 

http://history.nasa.gov/SP-367/f86.htm

 

If you posted this before, then my bad I did miss this. However, compromise is something that needs to be done for a fighter that's going to fly on both sides of Mach 1. The airliners were just an extreme example, you don't even need to be supersonic for wave drag to matter.

 

 

No it's down to maths, which you apparently don't understand. I've already asked you to use whatever figures you like in the same equations and see what they come out at but the fact is you don't understand the equations, which is why you're still talking.

You haven't taken into the account anything but the wings. I could come in here with the average fuel load F-35's and EF-2000's would have upon reaching their targets, the equations you posted would still not allow us to say which plane would have an advantage. The engine(s) isn't even taken into consideration.

 

Your early attempt at producing your own equations for lift and drag was also wrong as I pointed out. This tells me that you're not actually capable of understanding any explanation, hence this is a waste of time.

Yeah, I had a weird stalker gravity term that liked to follow the lift vector, you told me and I noticed the mistake.

 

It's 2500 over its entire lifespan of 30-40 years.

 

Take the F-15C, there were some 700 made (IIRC, don't quote me on the numbers), but it wasn't as if there was a force of 700 F-15C's, they were basically turning over fatigued airframes etc.

 

The F-35 was also supposed to be here a lot quicker and with less development pain. I like the idea of phasing out the older stuff and replacing it with the new, as long as it works. I think the USAF should be more Raptor and less Eagle right now. Had the F-35 been on schedule, I'd say the same about that plane too, but that obvious can't happen when there are only a handful of Lightnings that don't have the bugs worked out.

 

You're making assumptions based on useless data. I could tell you that an F-15 can hold an 11g turn, sustained. Does this data point do anything for you?

 

Apparently properly reading data, or trying to, is drivel.

If you posted this before, then my bad I did miss this. However, compromise is something that needs to be done for a fighter that's going to fly on both sides of Mach 1. The airliners were just an extreme example, you don't even need to be supersonic for wave drag to matter.

Ummm no. The discussion we were having was on maximum range, therefore we're only talking about subsonic cruise.

 

You haven't taken into the account anything but the wings. I could come in here with the average fuel load F-35's and EF-2000's would have upon reaching their targets, the equations you posted would still not allow us to say which plane would have an advantage. The engine(s) isn't even taken into consideration.

Are these the same engines that can't sustain a turn above 5g? I've accounted for wings and weight. Two very important issues for a thing known as flight.

 

Yeah, I had a weird stalker gravity term that liked to follow the lift vector, you told me and I noticed the mistake.

Yeah... no. It was just plain wrong - no pun intended.

 

It's very much a square relationship.

Is it now? Please show that mathematically.

 

Cf = Tw/(0.5*Density*v^2)

 

Tw = F/A

 

FOr turbulent flow

 

Cf = 0.582/(Re^0.2)

 

Re = v*chord/kinematic viscosity

 

As you can see the larger chord of a Typhoon/Rafale will actually reduce Cf slightly, mitigating some of the affect of wing area, when Cf is multiplied by it to give the drag component for turbulent skin friction.

 

Now let's look at the fuselage:

 

Page 11

http://faculty.dwc.edu/sadraey/Chapter%203.%20Drag%20Force%20and%20its%20Coefficient.pdf

 

As

 

Cf = 1.327/(Re)^0.5 (laminar flow)

 

Re = Density*V*L/air viscosity

 

Again the Typhoon is longer and the fuselage is smaller too.

 

You can do any calc. you like and the F-35 always comes out on the bottom.

 

Apparently properly reading data, or trying to, is drivel.

No but pecking away at a keyboard like a malnourished pigeon is.

 

Funny thing is, if I'd told you before Flight Global's article that the F-35 would have very poor sustained turn performance based on the same principles, you'd have come up with exactly the same bullshit.

 

I guess I should just wait for Lockheed's range apology rather than arguing.

 

It's intuitively obvious to knowledgeable people that small wings and large weight is bad for range. If you wish to prove an exception, the burden of proof is really on you not me.

It's 2500 over its entire lifespan of 30-40 years.

 

Take the F-15C, there were some 700 made (IIRC, don't quote me on the numbers), but it wasn't as if there was a force of 700 F-15C's, they were basically turning over fatigued airframes etc.

That's exactly what I am talking about. Build 500 instead of 2500 over 30 to 40 years. It worked with F-15's, it can work with F-35's too.

 

Reminder: SAM = Stealth STOP!

How are the F-35's wings small? It has more wing area than an F-16, and probably more total lifting surface. The wing loading on the F-35 will end up being very similar to that of an F-16.

F-35's aren't F-15 replacements. They're replacing F-16's, and to some degree A-10's and F-15's as well. How many F-16's were there built for the USAF? The USAF currently operates over 1200 F-16's ... if this is the case, then the number of needed F-35's to phase out F-16's is right on the mark.

 

That's exactly what I am talking about. Build 500 instead of 2500 over 30 to 40 years. It worked with F-15's, it can work with F-35's too.

 

Reminder: SAM = Stealth STOP!

Edited February 1, 2013 by GGTharos

How are the F-35's wings small? It has more wing area than an F-16, and probably more total lifting surface. The wing loading on the F-35 will end up being very similar to that of an F-16.

Afraid not. Even the A variant is marginally higher, even at empty. At full fuel wing loading it's a lot higher. And the F-16 never had great range but it at least had the TWR to compensate in turns and a smaller fuselage to drag around.

The F-35 with 18000lbs of fuel (that would be about the same as the F-16 having 2-3 internal fuel tanks) and loaded with weapons has something around 90-92lb/ft loading. The F-16 under the same same conditions will have about the same wing-loading.

 

Once they're both down to half fuel the F-16 does better on wing loading, doesn't much matter in TWR, and it's about to run home where the F-35 can keep turning.

 

The difference in wing loading at that point will be made up by drag if the F-16 is carrying pylons, which it probably would be - unless of course we're talking about block 30 F-16, then sure, lighter plane, big engine, cool.

 

The question is, who cares? You're not going to accomplish much of anything these days with a block 30 in an environment where you need an F-35 anyway, and it isn't as if a block 30 F-16 with a combat load has a particularly stellar range either.

 

Afraid not. Even the A variant is marginally higher, even at empty. At full fuel wing loading it's a lot higher. And the F-16 never had great range but it at least had the TWR to compensate in turns and a smaller fuselage to drag around.

The F-35 with 18000lbs of fuel (that would be about the same as the F-16 having 2-3 internal fuel tanks) and loaded with weapons has something around 90-92lb/ft loading. The F-16 under the same same conditions will have about the same wing-loading.

I don't believe you can run that comparison. The F-16 is a smaller, lighter aircraft (by more than 10,000lbs), it doesn't use as much fuel per km. It's like asking what happens to an F-16's performance if you add a 747's fuel load. And nobody said the F-16 had great range anyway.

 

Besides that, can a 5th gen fighter even claim to be a 5th gen fighter with 3rd gen turning performance? Surely it's actually gen 3.5 or something. Maybe it averages out as gen 4.

Sure I can. The F-35 is replacing F-16's. I also have some idea of the caveats of this comparison. The F-16 was conveived as a lightweight fighter, and that is what it is. The F-35 was no such thing; it's a heavy strike aircraft that can penetrate enemy anti-air defenses.

 

I don't believe you can run that comparison. The F-16 is a smaller, lighter aircraft (by more than 10,000lbs), it doesn't use as much fuel per km. It's like asking what happens to an F-16's performance if you add a 747's fuel load. And nobody said the F-16 had great range anyway.

 

Easily. It all depends on what you want to do with it. Can a 4.5 gen fighter like the SH claim to be a 4.5 gen fighter with 3rd gen sustained turning ability?

 

The F-35 will easily surpass the performance of legacy fighters when it comes to doing its job. You seem to be ignoring a whole bunch of things in your argument.

 

There's no insane advance in engine thrust like there was from the F-4 to the F-15 for the 5th gen fighters.

 

The F-35 can actually take advantage of more of its range because it doesn't need to resort to low altitude flight segments for a lot of its work, where other aircraft will eat up operational radius doing just that. It is entirely capable of carrying stand-off weapons internally, even if they're not the funkiest, longer ranged things around. It won't matter, because it can get closer to use them, and if it wants to use the longer range stuff, the fact that it gives up stealth doesn't matter either because it never gets close enough in that case anyway. On the other hand, where other aircraft are packing on external fuel tanks along with those munitions, the 35 simply does not need to, and it flies cleaner. Does this make a difference? I'm sure it does something.

 

It brings enough technology to the battlefield on its own that you can actually cut down on some supporting aircraft, so right there it allows you to either save money or allocate assets elsewhere.

 

There are several versions of it built, each with specific service in mind - and you should know this, but I guess you're too busy throwing aerodynamics around to realize that you need to compare it with respect to its designed purpose and how other aircraft would fare in similar situations.

 

The funniest thing is that you're taking a few numbers from that article to mean something, when they're entirely meaningless because they lack context. So what if maneuverability was reduced? At what altitude? An F-15C with a combat load has trouble sustaining more than 5g above 20000' too.

 

Besides that, can a 5th gen fighter even claim to be a 5th gen fighter with 3rd gen turning performance? Surely it's actually gen 3.5 or something. Maybe it averages out as gen 4.

Ummm no. The discussion we were having was on maximum range, therefore we're only talking about subsonic cruise.

 

You post what was supposed to be the CD for "any maneuver", except it was missing terms. I basically put the maneuvering ability of any plane in the most basic form you can get (with a typo on gravity) and then you commented on why I was using forces that were not in the direction of acceleration (despite the fact they were by default).

 

But OK, if you want to talk about range only, you've got nothing on you 3rd gen agility claim.

 

And as far as range goes, I've seen nothing on engine efficiency.

 

 

Are these the same engines that can't sustain a turn above 5g? I've accounted for wings and weight. Two very important issues for a thing known as flight.

So you've accounted for gliders dogfighting?

 

Also 5 g is pretty impressive.

 

http://img704.imageshack.us/img704/7035/f15str.png

 

The F-35 handily beats the F-15's 2 g.

 

 

 

Is it now? Please show that mathematically.

 

Cf = Tw/(0.5*Density*v^2)

 

Tw = F/A

 

FOr turbulent flow

 

Cf = 0.582/(Re^0.2)

 

Re = v*chord/kinematic viscosity

 

As you can see the larger chord of a Typhoon/Rafale will actually reduce Cf slightly, mitigating some of the affect of wing area, when Cf is multiplied by it to give the drag component for turbulent skin friction.

 

Now let's look at the fuselage:

 

Page 11

http://faculty.dwc.edu/sadraey/Chapter%203.%20Drag%20Force%20and%20its%20Coefficient.pdf

 

As

 

Cf = 1.327/(Re)^0.5 (laminar flow)

 

Re = Density*V*L/air viscosity

 

Again the Typhoon is longer and the fuselage is smaller too.

 

Yeah on the ^2 I misread your post, I was talking about V^2, and I had thought you were saying that skin friction drag didn't care about V^2.

 

For the rest of the above, well I basically said that already.

 

You can do any calc. you like and the F-35 always comes out on the bottom.

Calculations involving half a plane aren't always interesting.

 

 

 

 

Funny thing is, if I'd told you before Flight Global's article that the F-35 would have very poor sustained turn performance based on the same principles, you'd have come up with exactly the same bullshit.

 

You did tell me, and look at what happened. Poor sustained turning performance? Where?

 

It's intuitively obvious to knowledgeable people that small wings and large weight is bad for range.

It's pretty obvious that fuel fits in there too.

 

And that if someone's arguing that WL is so important for range, it makes no sense that a plane with WL no worse than most of the competition (F-35) the range should be no worse.

You post what was supposed to be the CD for "any maneuver", except it was missing terms.

No. The equations were for any manoeuvre but we were just discussing range. You probably can't remember, nevermind.

 

So you've accounted for gliders dogfighting?

 

Also 5 g is pretty impressive.

 

http://img704.imageshack.us/img704/7035/f15str.png

 

The F-35 handily beats the F-15's 2 g.

I'm curious. How are you reading that graph because the maximum sustained turn rate there for the F-15 is 9g unless you're looking at 40,000ft only. What was it you said earlier about reading?

 

The Typhoon was built around sustained turn rates at supersonic speed:

 

http://www.eurofighter.com/fileadmin/web_data/downloads/misc/TechGuideENG.pdf

Edited February 1, 2013 by marcos

How are you reading the STR numbers from that article? That is Exorcet's point.

 

I'm curious. How are you reading that graph because the maximum sustained turn rate there for the F-15 is 9g unless you're looking at 40,000ft only.

This thread is just...

How are you reading the STR numbers from that article? That is Exorcet's point.

Worse than an F-16

 

http://forums.airforce.ru/attachments/holodnaya-voina/7591d1183937649-f-16c-acceleration0.gif/

http://forums.airforce.ru/attachments/holodnaya-voina/7667d1184402615-f-16c-sustained-turn0.gif/

 

 

and almost as bad as these apparently.

 

http://forums.airforce.ru/attachments/holodnaya-voina/7581d1183834275-f-4e-acceleration.jpg/

http://forums.airforce.ru/attachments/holodnaya-voina/7569d1183809027-f-4e-sustained-turn.gif/

Edited February 1, 2013 by marcos

... where's your F-35 chart? And why are you showing me fuel consumption instead of STR? I asked about STR figures.

 

Worse than an F-16

... where's your F-35 chart?

I believe they're still re-drawing it.:lol:

 

 

.And why are you showing me fuel consumption instead of STR? I asked about STR figures.

 

It shows acceleration figures too which was part of the FG article.

Edited February 1, 2013 by marcos

It's pretty obvious that fuel fits in there too.

Seriously? You just keep typing? Yes, fuel is important and teh F-35 has more of it but, as already proven, uses more of it.

 

As regards your point on engine efficiency.

 

http://en.wikipedia.org/wiki/Eurojet_EJ200

 

22g/kNs = 353g/lbf/hr = 0.777lb/lbf.hr

 

http://en.wikipedia.org/wiki/SNECMA_M88

 

0.78lb/lbf.hr

 

http://en.wikipedia.org/wiki/Pratt_%26_Whitney_F135

 

0.886lb/lbf.hr

 

Very big engine gulping a lot of fuel.

 

And that if someone's arguing that WL is so important for range, it makes no sense that a plane with WL no worse than most of the competition (F-35) the range should be no worse.

No worse than most of the competition? Go figure.

Nice try.

 

I believe they're still re-drawing it.:lol:

Program officer visits integrated F-35 testing facility

 

http://www.af.mil/news/story.asp?id=123334726

Nice try.

 

The original goals:

 

http://www.f-16.net/f-16_forum_download-id-14791.html

 

 

Not only have the objectives been missed but the threshold has been failed.

Edited February 1, 2013 by marcos

Imho this whole F-35B grounding thing is a non-event: http://www.aviationweek.com/Article.aspx?id=/article-xml/asd_01_30_2013_p01-02-542267.xml&p=1

Ok, that is getting more interesting.

 

I guess I could go digging through my charts to see what sort of configuration the F-16 and the F-18 are using, I don't know who the footnotes are referring to.

 

EDIT: Nevermind, I finally spotted where they go :P This doesn't address the F-16 and F-18 configurations however.

Edited February 1, 2013 by GGTharos

Seriously? You just keep typing?

Great minds think alike?

 

Yes, fuel is important and teh F-35 has more of it but, as already proven, uses more of it.

That hasn't been proven anywhere, you just happen to have range figures that correspond to unknown flight profiles and weights that are bigger for non F-35 aircraft, well except the ones that's aren't bigger but you don't really consider.

 

As regards your point on engine efficiency.

 

http://en.wikipedia.org/wiki/Eurojet_EJ200

 

22g/kNs = 353g/lbf/hr = 0.777lb/lbf.hr

 

http://en.wikipedia.org/wiki/SNECMA_M88

 

0.78lb/lbf.hr

 

http://en.wikipedia.org/wiki/Pratt_%26_Whitney_F135

 

0.886lb/lbf.hr

 

Very big engine gulping a lot of fuel.

When sitting on the tarmac with the throttle at max? I don't think there's much to argue about there, the range would be zero for both planes.

 

That's also TSFC, not fuel consumption, so if the F-35 is less draggy and needs less thrust to cruise, it could use less fuel even if it had a high TSFC.

 

No worse than most of the competition? Go figure.

Yeah, the plane just happens to carry more fuel than the competition, but opponents somehow turn that into a bad thing.

 

About the only con I can think of is that the F-35 can't simply press Jettison to shave off a few thousand pounds of weight like you can with wing tanks, but then the F-35 wouldn't suffer from the drag of wing tanks or the threat of being seen first which negates the need to drop anything.