What will the Government buy if the F35 is cancelled?

[telecat]

Looking on the net it appears that the F-35 program has "slipped" so badly that the Next gen Fighter is already appearing on the USAF's horizon. It also looks like the various sections of the US flying forces will be allowed to develop independently. Primarily down to the cost over runs on Joint projects like the F35.

[telecat]

doogz said:

telecat said:

You would need an engine that could "bleed" thrust though a second outlet into a vent tunnel or set of nozzles forward and also provide some thrust to the "normal" outlets which would be fully variable like the F22 or the F35B. What I would be looking for would be an application of existing reliable tech as against the rather Heath Robinson Yak technology they are using at the moment. Let's face facts the Harrier has been in service for 50 Years and counting. The YAK was dead after 30 and it never reliably went into combat. It's a Dead end technology. I do not think that throwing modern engineering at it is ever going to work either.

As it stands Rolls-Royce and BAE have produced what appear to be viable concepts for a Supersonic V/STOL fighter that do not stray too far from the Harriers concept. The costs couldn't have been worse and the lead time even with MOD and DOD interference could have been a lot better.

Why?


Why can't a compressor be powered by the GT PTO/shaft, like the large ducted fan on F35 is?

As a concept No reason. Operationally it just is not a good enough solution. It's an unsuccessful idea dropped by it's Makers and it never sold one Plane outside it's original customer.

[JVaughan]

telecat said:

Looking on the net it appears that the F-35 program has "slipped" so badly that the Next gen Fighter is already appearing on the USAF's horizon. It also looks like the various sections of the US flying forces will be allowed to develop independently. Primarily down to the cost over runs on Joint projects like the F35.

Good job they have managed to get some fkwitts to commit to buying a bunch of them for their next generation carrier fleet

[Mave]

telecat said:

As a concept No reason. Operationally it just is not a good enough solution.

Again, why? What is the operational requirement that is better suited by a pair of engines with extensive ductwork?

[telecat]

Mave said:

telecat said:

As a concept No reason. Operationally it just is not a good enough solution.

Again, why? What is the operational requirement that is better suited by a pair of engines with extensive ductwork?

It looks to have better survivability and done right would allow a smaller fighter or greater volume for fuel etc. The design is one Lockheed Martin developed with Yakovlev for the 141 so it's greatest asset is that the design came cheap.

[Mave]

telecat said:

It looks to have better survivability and done right would allow a smaller fighter or greater volume for fuel etc.

Have you got any explanation, or links to something supporting that view? I can't reconcile "greater volume for fuel" with all the space these ducts and trap doors will need.

[IanMorewood]

I think the ducted fan/fans option still has lots of development potential the trouble is getting enough thrust without adding much weight.

[Mave]

I think the problem with taking the cold lift from the fan of the propulsion engine is that you fundamentally constrain the gas turbine to a cycle which is unsuited to supersonic propulsion.

[cpufreak]

doogz said:

Dr Jekyll said:

And the Lightning.

No it's not.

both "original" lightnings, the English Electric Lightning and the Lockheed P-38 had two engines.

The F35 isn't commonly referred to as the the lightning. hence the confusion.

[anonymous-user]

Mave said:

I think the problem with taking the cold lift from the fan of the propulsion engine is that you fundamentally constrain the gas turbine to a cycle which is unsuited to supersonic propulsion.

It's not just the engine, it's the critical intake duct proportioning that is difficult.

For a zero speed hover, you need a MASSIVE intake duct (look at how big the Harriers was for example!) that won't choke at low dynamic pressure, and for high speed flight, one that can efficiently trap the critical shock and decelerate the incoming air. Add it the requirement for the compressor section to accept massively different mass flow depending on flight regime and the whole thing becomes a bit of a nightmare (which the harrier sensibly avoided by saying sub-sonic)

[Mave]

Those are the kinds of things I was referring to when I said f35 is fundamentally different to the harrier. Engine positioned to allow a decent intake length, with effective supersonic recovery. Engine cycle set to give high specific thrust, low frontal area, and some level of supercruise. Effect of lift fan on -A and -C minimised - maybe the F135 diameter could have been pulled in a smidge if it didn't need to power the -B

[Halmyre]

cpufreak said:

doogz said:

Dr Jekyll said:

And the Lightning.

No it's not.

both "original" lightnings, the English Electric Lightning and the Lockheed P-38 had two engines.

The F35 isn't commonly referred to as the the lightning. hence the confusion.

I think it's just the UK-delivered variants that are supposed to be 'Lightning II' (for some unfathomable reason)? If so, it's a bit of an insult to the original Lightning (by which I mean the English Electric jet).

[Mave]

Halmyre said:

I think it's just the UK-delivered variants that are supposed to be 'Lightning II' (for some unfathomable reason).

Nope, it's the international designation.

[Mojocvh]

Mave said:

Those are the kinds of things I was referring to when I said f35 is fundamentally different to the harrier. Engine positioned to allow a decent intake length, with effective supersonic recovery. Engine cycle set to give high specific thrust, low frontal area, and some level of supercruise. Effect of lift fan on -A and -C minimised - maybe the F135 diameter could have been pulled in a smidge if it didn't need to power the -B

Perhaps Pratt have more important things, that have already fallen behind schedule, to sort first.

Engine test airframes flying but NO mod kits delivered "on schedule" par for the course.

Flight testing continuing, airframes now "limited" due to some other undisclosed reason apart from the circular saw Pratt.


£100 million 2.5g fighter. Ridiculous.

Oh btw, whatever happened to that STEALTH thing again?

RAF weapon fit, spot the flaw in the plan....

[Mave]

Mojocvh said:

£100 million 2.5g fighter. Ridiculous.

Have you got a source for that 2.5g?

[Mave]

Mojocvh said:

Oh btw, whatever happened to that STEALTH thing again?

RAF weapon fit, spot the flaw in the plan....

Are you suggesting that all RAF missions fly with the same weapons fit?

[IanMorewood]

Don't think that's the suggestion, but it's primary is as a strike aircraft in UK service, so drop tanks and thousand pounders would be a not uncommon loadout to expect.

[Mojocvh]

Mave said:

Mojocvh said:

£100 million 2.5g fighter. Ridiculous.

Have you got a source for that 2.5g?

safety limitation due to the fan moving; they have an extra 0.7g more than I originally specified.

http://aviationweek.com/defense/f-35-test-jets-und...

[Mojocvh]

Mave said:

Mojocvh said:

Oh btw, whatever happened to that STEALTH thing again?

RAF weapon fit, spot the flaw in the plan....

Are you suggesting that all RAF missions fly with the same weapons fit?

$$$$tealth, isn't that why we were duped into buying the it in the first place? Then the shorter ranged, heavier, slower, even less maneuverable [!!] F35B via Cameron, so wheres it at now?? Flying about with no internal weapons that's where.

35 tons, 35 TON single seat aircraft.....hmm

http://blogs.reuters.com/great-debate/2014/07/14/p...

Oh and a more detailed report...

http://www.defense-aerospace.com/article-view/feat...

Edited by Mojocvh on Wednesday 24th December 14:56

[Mave]

Mojocvh said:

Mave said:

Mojocvh said:

£100 million 2.5g fighter. Ridiculous.

Have you got a source for that 2.5g?

safety limitation due to the fan moving; they have an extra 0.7g more than I originally specified.

http://aviationweek.com/defense/f-35-test-jets-und...

That's not a $100M 2.5g (or 3.2g) jet. That's a jet that's got a limitation while they roll out a mod (either by doing the "burning in" process, or by modifying the engines.