F-35B vs Harrier

JohnR

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A series of questions that I have been looking to answer for a while:

1) What are the advantages of the F-35B over the Harrier? I can see that it must be technically simpler to achieve supersonic performance as it has essentially conventional afterburner. However it has the disadvantage; as with aircraft such as the French Balzac with its lift engines, that it is carrying around the dead weight of the lift fan when in conventional flight.

2) Has the Harrier/Pegasus concept reached the end of its development potential? What happened with the PCB burning trials? Why couldn't the afterburners be applied to the rear jets only?

I look forward to the responses of the more sagacious amongst us.

Regards.
 
Harrier F-35B
In Service In development
Subsonic Supersonic
Old New
Out of production Production starting
No work for any Congressional districts Billions of $$$$$$ all over USA
Hard to fly in transition - 'best pilots' only 'Easy' to fly - designed for average pilots
USMC use it USMC want it
RAF/RN use it RAF may want it, but do they want RN to have it??

And so on. Depends what you consider important. In the UK there is talk of B versus C (as in STOVL F-35 vs CV) which is another discussion (as is Tornado or Harrier in Afghanistan, chalk or cheese, apples or pears? etc.).

There is probably development potential for Pegasus (e.g. attempts to add RB.211 core in 1980s as seen in Andrew Dow's new book - http://www.secretprojects.co.uk/forum/index.php/topic,7804.0.html recommended) but it is out of production/fashion, as is the Harrier, so would need a lot of money to re-establish a production line, and new, more powerful engines in old airframes would cause additional airframe fatigue, meaning reduced airframe life, so making an update non cost effective, so only new planes would allow engine updates to make sense, raising the price etc.


Regarding PCB, despite what you read it may well have been workable, done right. Which reminds me, must finish this:
http://www.secretprojects.co.uk/forum/index.php/topic,6661.0.htmlhttp://www.secretprojects.co.uk/forum/index.php/topic,6661.0.html
 
A few thoughts off the top of my head:

The Pegasus arrangement is the antithesis of area ruling, although that is a bit less important nowadays with the thrust to weight available from modern jet engines.

The fan is a more efficient lifting device than the bypass air from the Pegasus and also provides a sizing benefit to the engine in cruise flight. There's a tradeoff of the weight of the fuel for hover fuel (roughly speaking, the Harrier hovers for six minutes on the amount of fuel a similar sized helicopter burns in an hour of hover) and cruise (the Pegasus is oversized for cruise so it's relatively inefficient) versus the weight of the fan. (It's also the pitch control, eliminating the piping of bleed air for pitch control required on the Harrier).

My guess is that plenum chamber burning is less efficient than a conventional afterburner, which is really saying something. Adding it only to the aft jet pipes requires a complete reconfiguration of engine/airplane to change the cg if it is to be used for VTOL. (You can't simply move the engine forward or the wing aft to balance the airplane for VTOL because then it will be out of balance for wing-borne flight.)

In any case, the F-35B is not only supersonic, it is much bigger, which means a "simple" upgrade to the Harrier doesn't meet the mission useful load requirement. Note that the X-32 engine installation was similar to the Pegasus, in that VTOL lift was provided by rotating nozzles, albeit only two. Its VTOL performance (on the same engine?) was almost an embarrassment, particularly compared to the X-35.

My personal opinion is that the X-35 approach was brilliant, if a bit risky in terms of clutch and gearbox development, and results in a VTOL jet fighter that's as useful as one is ever going to be. Not to mention that if you take out all that VTOL claptrap, there's volume for fuel/mission equipment in a conventional fighter, whereas the Pegasus/X-2 configuration is forever burdened with an engine located right where you want volume and disposable/variable useful load.
 
Tailspin Turtle said:
My guess is that plenum chamber burning is less efficient than a conventional afterburner

Not so, PCB is much more efficient than afterburning as the air starts much cooler. That's also why you wouldn't bother with augmenting the rear jets - much more efficient to use the cold ones.

There were studies of subsonic Harriers with PCB to boost vertical thrust, but more 'cold' thrust from a better fan etc. was seen as the way to go for a subsonic aircraft, despite PCB allowing the core to match cruise requirements better (but offsetting this by adding weight, more nozzle drag etc.).
 
Tailspin Turtle said:
Not to mention that if you take out all that VTOL claptrap, there's volume for fuel/mission equipment in a conventional fighter,

Or *unconventional* fighter equipment, such as a militarily-useful laser weapon. Harrier is never going to have such a thing.
 
Orionblamblam said:
Tailspin Turtle said:
Not to mention that if you take out all that VTOL claptrap, there's volume for fuel/mission equipment in a conventional fighter,

Or *unconventional* fighter equipment, such as a militarily-useful laser weapon. Harrier is never going to have such a thing.

There is volume in the Harrier. As it's subsonic it doesn't need area rule (which is all about volume distribution), and its total propulsion system volume (engine plus intake plus nozzles) is much less than many similar aircraft due to the short intakes/nozzles.

But it's no Death Star (maybe that would be cheaper than JSF?)
 
harrier said:
Tailspin Turtle said:
My guess is that plenum chamber burning is less efficient than a conventional afterburner

Not so, PCB is much more efficient than afterburning as the air starts much cooler. That's also why you wouldn't bother with augmenting the rear jets - much more efficient to use the cold ones.

There were studies of subsonic Harriers with PCB to boost vertical thrust, but more 'cold' thrust from a better fan etc. was seen as the way to go for a subsonic aircraft, despite PCB allowing the core to match cruise requirements better (but offsetting this by adding weight, more nozzle drag etc.).

Thanks for that clarification - I'd forgotten that it was applicable to the bypass air only. My speculation was based solely on the impression that it doesn't seem to be used elsewhere, which usually means that what seems like a good idea, isn't for some reason.
 
Tailspin Turtle said:
Thanks for that clarification - I'd forgotten that it was applicable to the bypass air only. My speculation was based solely on the impression that it doesn't seem to be used elsewhere, which usually means that what seems like a good idea, isn't for some reason.

A form of 'straight through' PCB is used in the RB.199 of the Tornado, where there is a ring of flame 'gutters' in the cold airflow from the fan (separate from the core augmentation), based on the PCB experience Bristol got in the 1960s. The fan of the RB.199 is a scaled version of the Pegasus's too.
 
harrier said:
Orionblamblam said:
Or *unconventional* fighter equipment, such as a militarily-useful laser weapon. Harrier is never going to have such a thing.

There is volume in the Harrier. As it's subsonic it doesn't need area rule (which is all about volume distribution), and its total propulsion system volume (engine plus intake plus nozzles) is much less than many similar aircraft due to the short intakes/nozzles.

Really? I was unaware that the Harrier had a drive shaft straight from the Pegasus engine to a large, hollow bay big enough for a generator, laser system and extendable turret.
 
I meant volume for fuel/mission systems, not 'Death Star' technology.

IMHO the 'Death Star' F-35 will never happen - for the same reasons laser sensor damage weapons were effectively 'outlawed'.

Nevertheless, with integrated electric drive an engine with a core the size of the Pegasus could generate a fair bit of power (and Bristol used integrated generators/starters for lift jets in the 1960s - see Andrew Dow's book), and need little extra volume to do so (and maybe gain some thrust from using excess heat as thrust, not dumping it into the fuel).
 
harrier said:
IMHO the 'Death Star' F-35 will never happen - for the same reasons laser sensor damage weapons were effectively 'outlawed'.

Odd, given that a C-130 has recently been equipped with a laser weapon and nobody of consequence started screaming about legalities.
 
On PCB: might be ok for VSTOL, but the usual problems with ground erosion and deck temperature would crop up in VTOL. Is Texhaust just as hot as with a conventional afterburner?

On lasers: maybe we'll start hearing some serious concern when solid state lasers are tested on a platform (or maybe not). I consider the current limited-shots noxious-chemical stuff that requires a C-130 to haul it around hardly practical. Good to build experience, though.
 
Tailspin Turtle said:
Note that the X-32 engine installation was similar to the Pegasus, in that VTOL lift was provided by rotating nozzles, albeit only two. Its VTOL performance (on the same engine?) was almost an embarrassment, particularly compared to the X-35.

The varient in the X-32 was actually significantly more powerful as it had to do VTOL on dry thrust. Max AB was something like 51k lbs vs 43k or so for the one in the X-35.
 
Orionblamblam said:
harrier said:
IMHO the 'Death Star' F-35 will never happen - for the same reasons laser sensor damage weapons were effectively 'outlawed'.

Odd, given that a C-130 has recently been equipped with a laser weapon and nobody of consequence started screaming about legalities.

Not to mention the fact that apparently China uses the very type of laser "harrier" says is outlawed on it's armored vehicles. ???
 
Well, there's also the fact that a F-35B with internal armament is way harder to detect and track than any Harrier version and also does not require a dedicated hardpoint for a targeting pod, the EOTS system being built in with common installation and mounting with the other F-35 variants. It's rather amusing that the first fully kitted out F-35 is a "B-model", BF-4 (well, alsmot fully kitted out, there's a couple systems lagging in flight qualification - I've heard it was the simple stuff, too, that bit the subcontractor). As to the clutch and transmission, the built on a lot of data from diverse applications to develop this equipment.
 
According to the Navy's standard aircraft characteristics document, the AV-8B (as delivered) would haul 2500 pounds of ordnance just over 500 nm (radius) on a hi-lo-hi profile, which is about the same as the F-35B. Not surprising, even though the JSF is much bigger, since internal fuel fractions are not that different and the AV-8B does not carry the extra weight associated with stealth, 7 g and supersonic speed.

It depends what you want to do. If you want a CAS/BAI platform and your plan is that, if there is a major air threat, a carrier-load of fighters will be backing you up, then a subsonic aircraft will do the job nicely and the Pegasus-type arrangement is proven, and by far the simplest way of doing STOVL that anyone has invented so far. The improvements in control technology implemented in the F-35B were developed and tested on a Harrier, and a new engine core (possibly based on an advanced CFM56) would bring further benefits.

Even a subsonic jet, too, could do some air defense, CAP and counter-cruise-missile CAP given good AEW and Meteors.

PCB, as I understood it, always had hot-gas recirculation issues (although if you landed on dry thrust that was less of a problem) but the real killer in the pre-JSF days was that it could not be made compatible with stealth.
 
On the other hand if you want to strike a defended target and/or you don't have a CVN backing you you're SOL with the Harrier and need the F-35. There's actually a pretty interesting clip of Harriers doing CAS and hitting undefended targets whilst operating off of LHDs up on youtube. I'll embed it when I get home later. The beauty of the F-35s versatility though is it frees up the CVNs from having to support F-35-equipped LHDs/As. With the carrier count down to 11 and headed for 10 or lower that will become increasingly important.
 
Laser blinding weapons are available from some countries, and probably the UK has its old Outfit DEC installations (allegedy brought down some Argentine aircraft in 1982) in a warehouse somewhere. However, once it was realised that such weapons tend to even up the odds for all users, and threaten to render piloted aircraft highly vulnerable (hence the BAe P.125 project with a 'buried' pilot), then the major western powers were happy to go along with 'banning' them, if only to slow their spread.

If (and that is a big one) a laser could be put in an F-35, it seems silly to do so.

1. Their range is limited, so the F-35 may need to get within visual range of a target (6nm), negating stealth - even if stealthy turrets can be made

2. There is a need to counter structural deflections and airflow etc. for aiming, meaning that speed and manouevre are likely to be limited

So these two mean you would have a supersonic, stealthy, manoueverable aircraft flying slow, steady and in visual range. Why? Plus it is not free - a probable need for major flight control software updates etc. to allow turret(s) where the lift fan will not be cheap, and structural mods would be needed, plus propulsion system mods too - the lift shaft is not used for flight above c.250kts.

Probably much easier/cheaper to use a new platform (UCAV?), or even a C-130. And then once China puts one in an AN-12, or on a merchant ship, and then someone figures out what that could do to a USMC landing in support of Taiwan.... more 'banning' will be called for, IMHO. Better not to let the 'other guy' have it than to have it yourself.

Regarding PCB, modern engines (even 1980s tech level) should allow 'minimum' PCB temps (800K) more for balance than for total thrust in VL. As Boeing found out, making the jet balance on dry thrust moves the engine too far forward (or adds ducting/volume as in old MDC 'Cactus'). What this means is that all the things of buckling decks, swabs over the side etc. are more to do with the core flow than PCB, i.e. same as for any naval aircraft. Hot Gas is highly configuration dependent, but alleviation is possible using rolling or creeping VL, nozzle 'blipping', front nozzle area variation to raise the fan surge margin etc. And stealth was an issue for the P.1230 that the UK studied with the US (Harrier configuration) as the hot gas flowed along the fuselage which meant IR emissions over a wide spectrum (plume and body radiation). On other configurations (P.1216) it was much less of an issue (plume only).

As LowObservable basically says, there is little point using a supersonic jet for a subsonic job, unless you want STOVL and there is only one aircraft type available with that ability. Hence the F-35B. But a Harrier 3, if funded, would probably find a market in USMC/RN, not that they would be able to get it funded.
 
One very important thing to keep in mind is that Marine Air exists to suppport the ground troops. It doesn't exist for long range strike, fighter sweeps, Alpha strikes, etc., except as they occur in relation to the mission of supporting troops on the ground. When you look at the Harrier and F-35B, you've got to keep that in mind. the reason they went for the AV-8A initially was because it brought something that no other air asset could reliably deliver: it could get to the troops really quick when the call went out. The AV-8B greatly improved this. They were willing to accept the slight increase in vulnerability due to it being slower than the -8A because of all the extra benefits it brought to CAS. They were willing to accept the maintenance issues (including having to take off the wing to remove the engine), because that was the price you paid to get what it did.

The F-35B brings better payload/range, superior avionics (in some cases arguably more than they need for CAS), greater survivability, lower maintenance, easier landing, all-weather (not just under the weather) capability, hopefully lower workload and more. I'm not all that convinced that the Marines would be wiling to pay extra for supersonic capability or stealth except that they're getting it for "free". The F-35 was really based around USAF wants, not surprising considering they were to buy the lion's share of the aircraft. USN and USMC could enhance or change as they were willing to pay for it, but were constrained to modifications of the basic USAF design. USMC didn't mind, since the F-35A with STOVL and a few avionics changes met their needs for a Harrier follow-on. They might have wanted a bit more endurance, but this way they didn't have to foot the bill for a whole new aircraft that they wouldn't have gotten funding for, anyway.

That's what made any Pegasus development moot. It would require a major redesign, and such a seperate effort simply wasn't going to be funded.

Regarding the lift fan, that was an outgrowth of a concept pioneered by DARPA. Actually there were originally two versions DARPA worked on. One, the clutch/gearbox version, was refined into the system on the F-35. The other was similar but used gas flow from the engine to power the fan. I may be totally wrong, but I seem to recall that MDD-led proposal for JAST originally used this concept but decided it was too risky and changed to the lift engine concept (which went in the same location that the fan would have).

sferrin's post may point to one of the reasons the X-32 lost. It was always more sensitive to weight control and engine thrust than was the X-35, and could only increase its lift through more engine thrust. 51,000 lbs in a production engine would be quite a stretch for the F119 derivative/F135, since all Pratt is promising is 43,000 (up from original 40,000 promise) max a/b, 38,000 STO, and 19,400 in the hover (15,700 engine and 3,700 roll post) for the production engine. This would probably have resulted in one engine for the "F-32B", and one for the "F-32A/C", cutting down on the commonality. GE's F136, BTW, is designed around 56,000 lbs of thrust, although they will probably derate it for the F-35 so as to get incredible durability.

As far as laser weapons -once they're in production status- not being used, I'm afraid that's wishful thinking. I believe they tried to outlaw machine guns, and we all know how well that worked. Actually, lasers are in some ways more humane--certainly less collateral damage if done right.
 
sferrin said:
The varient in the X-32 was actually significantly more powerful as it had to do VTOL on dry thrust. Max AB was something like 51k lbs vs 43k or so for the one in the X-35.

Didn't the X-35 have to also show VTOL capability on dry thrust? With the addition of the lift fan however. Even with the X-32s high engine output, Boeing still reportedly had to remove the landing gear bay doors and other weight. When you consider The weight increase from X-32 to F-24/F-32, I don't think it would have been a very practical configuration for anything but a significantly light aircraft. The X-32 had some good features, particularly I prefer the 2D Raptor-like TVC nozzle over the F-35's design. But problems with the X-32B and the major redesign at the last minute probably doomed it's chances. I still think the MDD JSF design should have been chosen for further development.

Regarding F-35B vs the AV-8B Plus, the only advantage I can see the Harrier having is the ability to VIFF, which was only used rarely, but allowed for some interesting maneuvers to be performed. It's gun pod also carries 80 more rounds of ammunition. But then there is the factor of price and if the F-35 program will survive.

Banning lasers designed to destroy optics and sensors haven't stopped the Chinese from putting that laser system on their new ZTZ-99 main battle tanks. I don't see an advantage to fitting such a system to the F-35. A laser system that could destroy targets however is a different matter.
 
harrier said:
Laser blinding weapons are available from some countries, and probably the UK has its old Outfit DEC installations (allegedy brought down some Argentine aircraft in 1982) in a warehouse somewhere. However, once it was realised that such weapons tend to even up the odds for all users, and threaten to render piloted aircraft highly vulnerable (hence the BAe P.125 project with a 'buried' pilot), then the major western powers were happy to go along with 'banning' them, if only to slow their spread.

If (and that is a big one) a laser could be put in an F-35, it seems silly to do so.

1. Their range is limited, so the F-35 may need to get within visual range of a target (6nm), negating stealth - even if stealthy turrets can be made

2. There is a need to counter structural deflections and airflow etc. for aiming, meaning that speed and manouevre are likely to be limited

So these two mean you would have a supersonic, stealthy, manoueverable aircraft flying slow, steady and in visual range. Why? Plus it is not free - a probable need for major flight control software updates etc. to allow turret(s) where the lift fan will not be cheap, and structural mods would be needed, plus propulsion system mods too - the lift shaft is not used for flight above c.250kts.

Probably much easier/cheaper to use a new platform (UCAV?), or even a C-130. And then once China puts one in an AN-12, or on a merchant ship, and then someone figures out what that could do to a USMC landing in support of Taiwan.... more 'banning' will be called for, IMHO. Better not to let the 'other guy' have it than to have it yourself.

Regarding PCB, modern engines (even 1980s tech level) should allow 'minimum' PCB temps (800K) more for balance than for total thrust in VL. As Boeing found out, making the jet balance on dry thrust moves the engine too far forward (or adds ducting/volume as in old MDC 'Cactus'). What this means is that all the things of buckling decks, swabs over the side etc. are more to do with the core flow than PCB, i.e. same as for any naval aircraft. Hot Gas is highly configuration dependent, but alleviation is possible using rolling or creeping VL, nozzle 'blipping', front nozzle area variation to raise the fan surge margin etc. And stealth was an issue for the P.1230 that the UK studied with the US (Harrier configuration) as the hot gas flowed along the fuselage which meant IR emissions over a wide spectrum (plume and body radiation). On other configurations (P.1216) it was much less of an issue (plume only).

As LowObservable basically says, there is little point using a supersonic jet for a subsonic job, unless you want STOVL and there is only one aircraft type available with that ability. Hence the F-35B. But a Harrier 3, if funded, would probably find a market in USMC/RN, not that they would be able to get it funded.


I dunno. Assuming you can get the power and stabilize the beam, a directed energy weapon would be a game changer. If we can laser designate from over 9 km today, certainly we'd be able to "lethal lase" from that distance in the not too distant future. Regarding the lift shaft speed being used < 250 knots now, that's because you aren't using the lift fan above that speed. Shouldn't be that difficult to use the shaft to generate energy internally above that speed.

These weapons will be game changers in a whole number of ways. If the turret can slew fast enough and you can generate the power, you don't really need to maneuver that much, although with modern systems, the amount of restriction can be minimized. It's just another (very fast) a/g weapon (not to mention with real potential a/a).

Banning simply won't work. You can't put the Genie back in the bottle. Once the technology exists, it's going to get out (which is why nanotechnology can be so scary), and it doesn't matter if the West "bans" it. I mean, isn't development of nuclear weapons by new countries "banned"?
 
Colonial-Marine said:
sferrin said:
The varient in the X-32 was actually significantly more powerful as it had to do VTOL on dry thrust. Max AB was something like 51k lbs vs 43k or so for the one in the X-35.

Didn't the X-35 have to also show VTOL capability on dry thrust? With the addition of the lift fan however. Even with the X-32s high engine output, Boeing still reportedly had to remove the landing gear bay doors and other weight. When you consider The weight increase from X-32 to F-24/F-32, I don't think it would have been a very practical configuration for anything but a significantly light aircraft. The X-32 had some good features, particularly I prefer the 2D Raptor-like TVC nozzle over the F-35's design. But problems with the X-32B and the major redesign at the last minute probably doomed it's chances. I still think the MDD JSF design should have been chosen for further development.

Regarding F-35B vs the AV-8B Plus, the only advantage I can see the Harrier having is the ability to VIFF, which was only used rarely, but allowed for some interesting maneuvers to be performed. It's gun pod also carries 80 more rounds of ammunition. But then there is the factor of price and if the F-35 program will survive.

Banning lasers designed to destroy optics and sensors haven't stopped the Chinese from putting that laser system on their new ZTZ-99 main battle tanks. I don't see an advantage to fitting such a system to the F-35. A laser system that could destroy targets however is a different matter.

Regarding VIFF, there were lots of air "battles" between the Harrier and other fighters. If everyone was restricted to visual combat and guns, the Harriers used to beat F-16s a lot. However, once missiles were allied, the VIFFing gave little or no advantage, and after using it the Harrier was sitting there out of energy. In the Falklands conflict, VIFF was not used in air combat, because the AIM-9L did so much more for the RN.
 
harrier said:
1. Their range is limited, so the F-35 may need to get within visual range of a target (6nm), negating stealth - even if stealthy turrets can be made

There's basically no such thing as a stealthy aircraft with an open weapons bay. So that arguement fails.

2. There is a need to counter structural deflections and airflow etc. for aiming, meaning that speed and manouevre are likely to be limited

And there's no such thing as being truly stealthy while jinking all over the sky. So *that* arguement fails.


So these two mean you would have a supersonic, stealthy, manoueverable aircraft flying slow, steady and in visual range.

No, it means you'd have a fast stealthy aircraft that could get near the designated target area in a hurry without being seen, and then pop open it's turret, zap the enemy - a truck, a weapons cache, a missile on the pad or in flight - and then button up and get the hell out of Dodge in a hurry.

the lift shaft is not used for flight above c.250kts.

I've not heard of too many aircraft that hover at 250 knots. Have you?
 
As a side note, we already have operational examples of airborne lasers. What's a DIRCM if not that? Sure, it operates at a fraction of the power/range of an offensive weapon, but extrapolate a decade or two in the future and you could have something like a "Boulton-Paul-Defiant-on-steroids" with turreted laser, able to take out any incoming missile, or anything within its field of fire and range. I especially like the possibility of decoupling the flight vector and the aim point, and AA and Air to ground use combined in one weapon. This would truly be HOBS and dual-role.
Would this make dogfighting a thing of the past? (heard that one before...)

Ok, I'll stop before I make an ass of myself. I admit this is a stretch, and picking the Defiant as an example hardly conjures success. I'm sure they must have felt pretty good at Boulton Paul before the war, but it's still an entertaining thought.
 
1. Their range is limited, so the F-35 may need to get within visual range of a target (6nm), negating stealth - even if stealthy turrets can be made

There's basically no such thing as a stealthy aircraft with an open weapons bay. So that arguement fails.


Well, it's one thing to be non stealthy for a moment out of visual range above cloud while dropping a JDAM at 10-20nm, and quite another within visual range (lasers penetrate clouds? I doubt it) of a 57mm gun crew.


2. There is a need to counter structural deflections and airflow etc. for aiming, meaning that speed and manouevre are likely to be limited

And there's no such thing as being truly stealthy while jinking all over the sky. So *that* arguement fails.

So it won't be manouevering? The 57mm crew will be pleased.


So these two mean you would have a supersonic, stealthy, manoueverable aircraft flying slow, steady and in visual range.

No, it means you'd have a fast stealthy aircraft that could get near the designated target area in a hurry without being seen, and then pop open it's turret, zap the enemy - a truck, a weapons cache, a missile on the pad or in flight - and then button up and get the hell out of Dodge in a hurry.

This is the case for a single pass, single target attack - OK, but surely the main advantage of a laser is multi-target attacks. Why bother carrying one then, and could a single pilot identify many targets even if he wanted to, low and fast? Unlikely with humane rules of engagement.

the lift shaft is not used for flight above c.250kts.

I've not heard of too many aircraft that hover at 250 knots. Have you?
It needs to transition. Presumably the structural loads/whipping calculations etc. are based on speeds up to wing borne flight plus a bit over. Pull a few g with the shaft spinning? Hmm, 57mm crew see the target explode on its own!
 
If cluster bombs, landmines, white phosphorous (ahem!), chemical weapons, biological weapons and so on can be controlled then so can any weapon. Wars are the continuation of politics by other means, not the negation. Jaw jaw is better than war war etc.

The case for the laser is similar to that for the Hyper Velocity Missile in the 1980s. Many kills made quickly, turrets to fire them etc. Where are they now? Rules of engagement slowed things down, the swarms of T-72s never materialised.
 
This thread is a classic example of how such questions are very hard to answer with simple textual arguments (two-three sentences or less). But anyway let me wade in! Firstly a few historical corrections (in chronological order):

One of the many unfortunate things about the Boulton Paul Defiant and the British 1930s turret fighters is that 99.9% of the commentary about them forgets or ignores what they were designed for. It wasn’t to be a fighter able to dogfight with all angle fires. It was to bean anti bomber aircraft. At the time there was a lot of concern about the armaments competition between bombers and fighters and potential solutions were developed including engine block mounted cannons and turreted fighters. The idea of the turreted fighter was that the squadron would attack IN formation and in order to target the bombers the turrets would track – as the aircraft couldn’t manoeuvre as they stayed in formation. That way the hope was that each bomber would be subject to the fires of 48 x .303 Browning MGs as the Defiant squadron swept by wing tip to wing tip. So it has no applicability to trying to determine if contemporary LOAL, HOBS missiles are a good idea. Though I would have thought the extreme difference in technology, application and so on between the two would have been bluntly obvious.

The Harrier, especially the Sea Harrier, is an extremely good air to air platform despite lacking supersonic performance. The initial operational RN squadron achieved a 2.7 to 1 kill ratio against the USAFE Aggressor squadron and a 7 to 1 kill ratio against an F-15 squadron before going to the Falklands and decimating the Argentines. Supersonics in air to air engagement provides three things – rapid closing/escape and an energy boost. The later is the most important and is typically applied early on in the engagement so energy is high for missile shots and before maneuvering starts to strip energy. The SHAR – including the BVR capable FA.2 SHAR – has shown that it can go head to head with the best and win without this energy boost. Because the aircraft can sustain energy in manoeuvre better than most conventional fighters plus smaller size and tailored radar enables it to swap BVR shots at an advantage. These are many of the principals designed into the F-35 though it takes it to much greater extremes of capability than any Harrier could hope for. Pro-F-22 and anti-F-35 polemicists have created arguments that somehow supercruise is vital to low observable BVR combat but its just nonsense. You need to buy into a whole series of arguments, assumptions and false facts in order to accept these arguments.

VTOL aircraft are not naturally un-supersonic. There have been only TWO operational VTOL aircraft in service in the history of aviation (Harrier and Yak-38) so it shouldn’t be considered abnormal that none of them were supersonic. Especially since both are effectively first generation VTOL designs. What stopped their supersonic successors was not technical failure but lack of finances and political will. Of course the weight and volume of the VTOL equipment negatively impacts forward flight performance of a VTOL aircraft but this is no different to designing in radar and weapons and other compromises to drag, lift and thrust to weight ratio.

Finally on weapons limitations treaties I would hardly say that the cluster bomb and landmine bans have actually done that at all. Only a limited number of countries have signed up to these treaties. And those have done so not because of the weapon’s use in war but its secondary, unattended, impact on civilians. So if the use of DEW weapons means that every civilian within a 20km radius will suddenly lose their eyesight then maybe they will be an issue – but that’s not how lasers work. Limitations on weapons of mass destruction have been even far more effective but as current history has shown it only takes 2-6 countries to try and circumvent them to create globally destabilising effects. Lasers and other DEWs will not be banned. However like HVM they are subject to the effects of smoke. HVM was a great idea on paper until anyone actually fired one and it created a visual signature a little bit short of A-Bombing Hiroshima. Most DEWs are subject to considerable loss of power thanks to smoke, clouds, fog, etc. Which makes there use subject to weather and the best effort of the enemies Chemical Corps. But on a clear day and in the jet stream they will kill everyone.
 
Back in the early 1990s I attended an AIAA conference session on future fighters (this was pre-JSF). Someone presented a paper on a "laser fighter", arguing that it would not need to be agile - it was just equipped with top and bottom turrets for full-spherical, speed-of-light engagement.

F-14D - You raise an important point about "Marine air" and its evolution. In WW2 and earlier, Marine air involved Navy-type aircraft flown from land bases. In the jet era, with "island hopping" no longer an issue, it split into land-based CAS (with AU-1s into the late 1950s, then A-4s) and Marine-badge carrier units. And then there was the Short Airfield for Tactical Support (SATS) era, and then the Harrier.

The idea behind UK-US ASTOVL was always to bring the two threads back together again by replacing both the AV-8B and the Classic Hornet - and as we know that sputtered along until DARPA picked it up and it got rolled into JAST, then JSF. And even in the latter days of ASTOVL people were telling the Marines that they could add LO to the blend for very little extra cost, and that drove a wedge between the UK and US at that point.

The blending of DARPA's demonstrator into JAST was vital, because otherwise the Marine/UK requirement alone would never have got funded. But from a requirements and design viewpoint, the tail ended up wagging the dog, because a USAF/Navy/export CTOL/CV bird would have looked a lot different - two F414s, probably a bit longer overall (size was kept down in pursuit of a Classic Hornet-like empty weight), and possibly a different configuration.

And the X-32 came from a rather different direction - Boeing's vision of a radically low-cost, networked fighter for everybody, almost like a tri-service Gripen.

MD's abandonment of the gas-driven lift fan was partly on grounds of risk (you could argue that eliminating shaft, clutch and gears had value, but you had to have some pretty fancy VCE features in the main engine) but both BAE Systems and Northrop Grumman has concluded that the classic LPLC was the way to go. The main engine then became very easy (a stock F119 or something based on a CFM core) and the lift fan engine wasn't that much more complicated than either the gas- or shaft-driven systems. Personally I think they were right.
 
harrier said:
If cluster bombs, landmines, white phosphorous (ahem!), chemical weapons, biological weapons and so on can be controlled then so can any weapon. Wars are the continuation of politics by other means, not the negation. Jaw jaw is better than war war etc.

The case for the laser is similar to that for the Hyper Velocity Missile in the 1980s. Many kills made quickly, turrets to fire them etc. Where are they now? Rules of engagement slowed things down, the swarms of T-72s never materialised.

Cluster bombs have been "controlled" because you have to have a sophisticated air force to make use of them. So far, the only countries in the West that have such a capability have forgone using them recently , partly for lack of suitable targets and out of concern of collateral casualties, a sentiment not universally shared. Landmines are now called IEDs. The only reason the other weapons mentioned are controlled is because enough people have them that if they are used in offense, they, or something equally formidable will be used in retaliation. Does anyone seriously doubt that Saddam would not used CBW in Gulf War I had he not feared that the result would have been large areas of his empire would have been turned into molten glass?

Hypervelocity missiles weren't that much for turrets because unlike a laser, they are affected by airflow and the problems of launch off the flight vector. they did offer the prospect of a larger hjo escape zone for a/g use, and wouldn't necessarily have to have a warhead, making them easier to handle. Lasers aren't affected by those other issues, but they do have a more sophisticated requirement for generation. Hypervelocity died because the 90s came about and there were major cutbacks all over, some sensibly and a lot politically (including kicking the can down the road).

Frankly, I can't see what all the fuss about lasers is about, except that it's a new type of weapon and we all waste too much time and treasure trying to develop those.

Anyway, this is just a subset of the F-35B vs. Harrier issue and laser weapons probably needs its own topic.
 
LowObservable said:
Someone presented a paper on a "laser fighter", arguing that it would not need to be agile - it was just equipped with top and bottom turrets for full-spherical, speed-of-light engagement.

Wasn't that the idea behind the YAL-1A Airborne Laser program, anyway? The 747 is not exactly what you may call agile, but it would have served its purpose... The fact that the initial designation for the YAL-1A was probably the weird "YFC-36A" amply proves that you can make an airborne laser of just about anything that flies, even a cargo aircraft!
 
harrier said:
Well, it's one thing to be non stealthy for a moment out of visual range above cloud while dropping a JDAM at 10-20nm, and quite another within visual range (lasers penetrate clouds? I doubt it)

I believe IR lasers can penetrate clouds, within reason.

of a 57mm gun crew.

WOW! So, an F-35 orbiting at 35,000 feet above a thick cloud layer, waiting for a Scud to break through so it can zap the missile, can be shot down by a 57mm cannon???


2. There is a need to counter structural deflections and airflow etc. for aiming, meaning that speed and manouevre are likely to be limited

So it won't be manouevering? The 57mm crew will be pleased.

I'm sure they'll be *thrilled* when out of a clear blue featureless sky comes an invisible directed energy beam that sets their clothes on fire, melts their skin, explodes their ammo and sends them straight to the afterlife.


This is the case for a single pass, single target attack - OK, but surely the main advantage of a laser is multi-target attacks. Why bother carrying one then, and could a single pilot identify many targets even if he wanted to, low and fast? Unlikely with humane rules of engagement.

Humane? Like napalm, or something?

It needs to transition. Presumably the structural loads/whipping calculations etc. are based on speeds up to wing borne flight plus a bit over. Pull a few g with the shaft spinning? Hmm, 57mm crew see the target explode on its own!

You continue to make some odd assumptions. Why would a gun crew even know the F-35 was *there* until after it has done its thing and gone on its way?
 
Abraham Gubler said:
One of the many unfortunate things about the Boulton Paul Defiant and the British 1930s turret fighters is that 99.9% of the commentary about them forgets or ignores what they were designed for. [...] The idea of the turreted fighter was that the squadron would attack IN formation and in order to target the bombers the turrets would track – as the aircraft couldn’t manoeuvre as they stayed in formation. That way the hope was that each bomber would be subject to the fires of 48 x .303 Browning MGs as the Defiant squadron swept by wing tip to wing tip. So it has no applicability to trying to determine if contemporary LOAL, HOBS missiles are a good idea. Though I would have thought the extreme difference in technology, application and so on between the two would have been bluntly obvious.

I must admit I didn't think too much about all the implications before using the first vaguely similar aircraft I could think of for comparison. Are there more applicable examples?

Anyway, I found that posting the idea was useful because
a) The expertise of the forum members is a very good reality check
b) I appreciated your historical background on the particular tactical concept behind the Defiant. Most books omit this and only mention the difficulty for the pilot and gunner to coordinate an attack against a maneuvering target.

I guess one thing the Defiant does teach and that might be applicable here, is that it's risky to bet the house on a particular capability (that may or may not work out) at the detriment of the others. A "laser-fighter" might be a nice concept, but it can't be a one-trick pony. The laser installation cannot come at the expense of other aspects of the design as technological developments, CONOPS, ROE, or the hundreds of things that happen in practice may make that capability irrelevant.
 
It is important to establish a hierarchy of capability. Why does a fighter aircraft need agility? So it can manoeuvre to enable the pilot to retain situational awareness, bring the fighter’s weapons to bear on the target and deny SA and firing solutions to the threat. Because the fighter pilot does not have a full spherical unrestricted view of the world and a full spherical target engagement capability. It is because of these two things – restructured SA/engagement and the need to manoeuvre to provide SA and engagement – that high agility is required against an aware and manoeuvring threat.

Now if you equip the aircraft with a SA system and a weapons system that can detect and target other fighters across the full sphere then do you need agility? What purpose will agility serve?

Now because the Boulton Paul Defiant’s turret was designed to engage bombers it does not have a full spherical engagement capability. So the loss of agility caused by the increase in weight and drag of the turret made it highly vulnerable in a maneuvering fight against other fighters that could use their agility advantage to stay out of the field of fire of the turret and keep attacking the Defiant. If a turret fighter had two turrets - providing full spherical engagement - and was still fast enough so enemy fighters couldn't run away it might have been a different story.

But the ability to fight in close with other fighters without needing to manoeuvre provides distinct advantages. They include rapid weapons deployment – as no manoeuvre is needed to bring the threat into the firing arcs – and retention of high energy throughout the engagement. Which enables the non-manoeuvring, all angle SA/engagement fighter to control the geometry of the engagement as the other fighters rapidly bleed off energy as they manoeuvre.

Now none of this argument is to support building a non agile fighter. Agility is also important to enable rapid response to the appearance of threats and very quick engagement of targets – some of the strengths a fighter brings to situations outside of dogfighters. Though the importance of agility to a fighter’s lethality and survivability in air to air combat becomes a rapidly reducing metric.
 
Stargazer2006 said:
LowObservable said:
Someone presented a paper on a "laser fighter", arguing that it would not need to be agile - it was just equipped with top and bottom turrets for full-spherical, speed-of-light engagement.

Wasn't that the idea behind the YAL-1A Airborne Laser program, anyway? The 747 is not exactly what you may call agile, but it would have served its purpose... The fact that the initial designation for the YAL-1A was probably the weird "YFC-36A" amply proves that you can make an airborne laser of just about anything that flies, even a cargo aircraft!


Actually, YAL-1 was designed to kill Theater Ballistic Missiles at a range of 300-600 km. The reason it is in a 747 is to allow for extended loiters and to carry the chemical fuel needed for multiple hosts. Now it stands to reason that if it could kill missiles at those ranges it could kill aircraft a shorter ranges, but that's not the purpose of its existence.

However, this illustrates why you can't count on a "ban" of lasers Let's say the Administration does not kill it and the program survives, and even becomes operational. It's on patrol and its sensors, as well as external sensors detect an aircraft approaching dozens of kilometers away. The aircraft is hostile and it is illuminating the AL-1 with its fire control radar. The AL-1 naturally has no chance of evading a fighter. However, its laser is armed and operational. You think the crew is not going to take a shot or two at that fighter?
 
Reminds me of a technothriller of some years back where the crew of an E-3 slews the radar antenna around and htis full power to cook the pilot of an approaching hostile fighter; didn't kill him immediately, but he didn't live long thereafter.
 
Yet if a missile is launched at the YAL-1, it is still going to be quite a vulnerable target. I doubt the laser has sufficient accuracy for self-defense purposes. And if something gets behind it, the crew is out of luck.

I can envision a laser system on the F-35, but one with somewhat limited capabilities. I think with the first 6th generation fighters any "high end" designs will be relatively large and feature a laser system that provides 360 degree coverage, and can reliable be used to destroy incoming missiles targeting the aircraft.

Once such laser systems emerge, perhaps "maneuverability will be irrelevant", but you are still going to want a plane that doesn't handle like a bus. Speed is still going to be relatively important too. As for now when it comes to the whole situational awareness vs. maneuverability debate? Why not have both?

In my opinion, the only real chance the USMC and RN had of getting a new VTOL/STOVL aircraft in the current political climate was with the whole common airframe idea. I believe that separate CTOL/CV and VTOL designs would have some advantages compared to their F-35 counterparts, yet in today's budgetary environment it wasn't feasible. I imagine that without the VTOL requirement the JSF's airframe would not be so "conventional", would incorporate further stealth features and probably a 2D thrust vectoring nozzle. Picture a combination of the F-22 and YF-23 with one engine.
 
Colonial-Marine said:
Yet if a missile is launched at the YAL-1, it is still going to be quite a vulnerable target. I doubt the laser has sufficient accuracy for self-defense purposes. And if something gets behind it, the crew is out of luck.

It’s not as simple as that. The COIL on the AL-1 is meant to have a range of hundreds of miles. So who’s going to get close enough to launch a missile? And don’t waste our time with the AWACS killer nonsense. Until hypersonics are in service no missile can fly fast enough to make a >150 NM kill against anything other than an airliner. Further the AL-1 is not designed as a close combat platform. Like AEW&C, tankers, etc it will stay well behind the fighters. In such a circumstance long range laser sniping might be quite useful. AEW&C + AL-1 = air to air hunter-killer combination.

Colonial-Marine said:
I can envision a laser system on the F-35, but one with somewhat limited capabilities.

Why? What’s in an F-35 that will make any laser somehow limited? There is volume in the fuel/lift fan bay, torque for power generation and a pretty reasonable field of fire from such a position. Surely the capability of such a laser is entirely up to what kind of laser technology is available?

Colonial-Marine said:
Once such laser systems emerge, perhaps "maneuverability will be irrelevant", but you are still going to want a plane that doesn't handle like a bus. Speed is still going to be relatively important too. As for now when it comes to the whole situational awareness vs. maneuverability debate? Why not have both?

Which is why reducing things down to an all or nothing argument just makes fools of everyone. In the case of the F-35 it is going to be a very agile plane. But is it going to be so more agile than a Su-30 or a Mig-29 or a Pitts Special that it will out manoeuvre these aircraft with ease? Probably not, but it doesn’t need to. It will have the all angle SA and weapon systems (via missiles not lasers – at least to start with) and will be able to defeat them without recourse to turning and burning.

The dynamics of air to air combat are changing. Not that you would know it if all you did is listen to some of the more ‘vocal’ commentators out there…
 
Abraham Gubler said:
It’s not as simple as that. The COIL on the AL-1 is meant to have a range of hundreds of miles. So who’s going to get close enough to launch a missile? And don’t waste our time with the AWACS killer nonsense. Until hypersonics are in service no missile can fly fast enough to make a >150 NM kill against anything other than an airliner. Further the AL-1 is not designed as a close combat platform. Like AEW&C, tankers, etc it will stay well behind the fighters. In such a circumstance long range laser sniping might be quite useful. AEW&C + AL-1 = air to air hunter-killer combination.

The concern about "AWACS killing" missiles seems real enough, and honestly when talking about the E-3 or YAL-1, they are based on airliners. And how long can the chemical "battery" of the YAL-1 allow the laser to be fired?

Why? What’s in an F-35 that will make any laser somehow limited? There is volume in the fuel/lift fan bay, torque for power generation and a pretty reasonable field of fire from such a position. Surely the capability of such a laser is entirely up to what kind of laser technology is available?

Look at the position proposed for such a laser turret beneath where the lift-fan would be on the F-35A and F-35C. I doubt it can cover behind the aircraft, and I don't know if there would be room for a top laser turret as well. I can envisioned a laser setup on the bottom of the aircraft, much like a gun pod, but I am skeptical of the talk of turreted configurations. In my opinion to take full advantage of directed energy weapons, a fighter would have to be designed with that in mind from the start.

Colonial-Marine said:
Which is why reducing things down to an all or nothing argument just makes fools of everyone. In the case of the F-35 it is going to be a very agile plane. But is it going to be so more agile than a Su-30 or a Mig-29 or a Pitts Special that it will out manoeuvre these aircraft with ease? Probably not, but it doesn’t need to. It will have the all angle SA and weapon systems (via missiles not lasers – at least to start with) and will be able to defeat them without recourse to turning and burning.

I didn't say the F-35 wasn't agile enough, however I do believe incorporating a TVC nozzle at a later date, like that being tested for the Eurofighter would be a welcome addition, and not just for maneuverability reasons. Yet even for ground attack you want speed to be able to respond quickly and minimize your exposure to enemy fire. Plus you want a better turn capability than say a SR-71 or C-17. Even in a future with super-agile hypersonic missiles and lasers, your going to want more than a flying truck. Regarding my preference for a 2D TVC nozzle, a good part of my reasoning is due to stealth concerns. Yet reportedly the RCS of new low-observable 3D nozzles like that of the F-35 is comparable to 2D designs, so these concerns may be misplaced.

Regarding the F-35 air-to-air capabilities, without AIM-9X internal carriage it really lacks the ability to take advantage of all of the situational awareness systems at close range, at least until a new missile is fielded.

The dynamics of air to air combat are changing. Not that you would know it if all you did is listen to some of the more ‘vocal’ commentators out there…

Until such advanced laser systems emerge, I don't think we will see the demise of the dogfight. With sufficient numbers of 4.5 and 5th generation fighters, it is unlikely an enemy flying Migs and Flankers for example will get that close. And if you have some AIM-9Xs or IRST-Ts your probably won't use that gun. Yet that doesn't mean scenarios where the enemy gets the jump on us will never happen. Plus if stealth aircraft become more widespread, the dynamics here could change significantly.
 

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