F-35 agility enhancement

[chuck4]

Is it true that F-35's agility, weight and supersonic drag was purposely sacraficed to focus on range and the strike role, and thereby avoid political competition with F-22?

Was F-35 originally envisioned to be a supercruiser when it was specified that it use the same F119 engine as F-22?

In age of CAD/CAM, can a slimer, lighter version of F-35 optimized for air-air and sacraficing range and total weapon weight, be economically designed and built to supplement the F-22 fleet and oppose the likely much larger number of G5 supercruising heavy fighters from China and Russia?

 

[Kryptid]

Since the F-35B was based around a STOVL requirement, keeping the weight down would still be important.

 

[InvisibleDefender]

Is it true that F-35's agility, weight and supersonic drag was purposely sacraficed to focus on range and the strike role, and thereby avoid political competition with F-22?

Was F-35 originally envisioned to be a supercruiser when it was specified that it use the same F119 engine as F-22?

In age of CAD/CAM, can a slimer, lighter version of F-35 optimized for air-air and sacraficing range and total weapon weight, be economically designed and built to supplement the F-22 fleet and oppose the likely much larger number of G5 supercruising heavy fighters from China and Russia?

1. No
2. No
3. Sure, but who would want to pay for it?

 

[BDF]

In age of CAD/CAM, can a slimer, lighter version of F-35 optimized for air-air and sacraficing range and total weapon weight, be economically designed and built to supplement the F-22 fleet and oppose the likely much larger number of G5 supercruising heavy fighters from China and Russia?

I don't see the point. The F-22 was optimized for that role and even if you factor in having to restart the line its much more economical to build more F-22s than redesigning the F-35 to be competitive, even if you're accepting less performance. TAC BRAWLER results indicated that the F-22 was 10 times more effective against an advanced 4th generation threat than the F-35. That's a lot of ground to cover and I'm not at all convinced that a notional F-35D would be significantly cheaper than a F-22 would be. A RAND study estimated it'd cost approximately $13 billion to restart the F-22 line and build 75 jets. You'd probably have to spend close to that just to redesign and test a new F-35 variant. We should have build another 100 F-22s.

 

[Steve Pace]

Arguably, the Raptor is the baddest ass ALL-AROUND fighter on the planet. One F-22 - ONE, can take down anything in the sky. Even if the goverment shuts down tonight, Raptors rule! - SP

 

[SOC]

Arguably, the Raptor is the baddest ass ALL-AROUND fighter on the planet.

OVER the planet. ON the planet...well, there's this thing sitting at WPAFB, with another in California, that might disagree... ;D

 

[LowObservable]

Original question -

It wasn't totally political, but in the pre-JSF years the USAF avoided any spec for the Multi-Role Fighter (the notional F-16 replacement) that would have looked like an ATF-Lite.

One JSF requirements started to gel, it was pretty clear that 2 x 2K bombs, STOVL systems &c were not going to fit into a supercruiser that would fit on an LHA deck. Also, the winning CDA teams both boosted bypass ratio to get vertical thrust.

A single-engine supercruiser would be a new airframe...

 

[Grey Havoc]

What was supposed to be; A JSF program presentation from September 2008 titled: F-35 Lightning II; Technology Transition

 

[TaiidanTomcat]

Is it true that F-35's agility, weight and supersonic drag was purposely sacraficed to focus on range and the strike role, and thereby avoid political competition with F-22?

Was F-35 originally envisioned to be a supercruiser when it was specified that it use the same F119 engine as F-22?

In age of CAD/CAM, can a slimer, lighter version of F-35 optimized for air-air and sacraficing range and total weapon weight, be economically designed and built to supplement the F-22 fleet and oppose the likely much larger number of G5 supercruising heavy fighters from China and Russia?

I guess it all comes down to how important super cruise is to you. With talk of the CUDA missile, a lot of countries might opt for more AAMs in the F-35's wider bays than the slimmer version you propose. YMMV

 

[Mach42]

What would have happened if the marines made do with STOL? How would the plane change if the requirements were modified for no hovering from the beginning? Could that F-35 adequately fill the role assigned to the current F-35B?

 

[chuck4]

What would have happened if the marines made do with STOL? How would the plane change if the requirements were modified for no hovering from the beginning? Could that F-35 adequately fill the role assigned to the current F-35B?

I suspect the following would have been the result:


1. Engine would be moved further back in the fuselage because these is no more requirement for the nozzle to be closer to center of gravity during hover


2. Moving the engine back would release the need to wrap the back ends of the weapon bay around the fan casing. So that might either make the fuselage slimmer, or make room for the main landing gear to fit inside the fuselage instead of in bulges under the wing. Either way the drag characteristics of the plane should improve.


3. The shaping of the fuselage behind the cockpit was originally dictated by the desire to fit the large lift fan in the B version while preserving a common stealth shape factor for all three versions. Eliminating lift fan would facilitate lower hump behind the fuselage and potentially better all round cockpit visibility.


4. The elimination of stvol requirement would also remove the requirement for the bulky, stvol suitable ejection seat. This ejection seat is also disliked for blocking rear vision.


This f-35 can't obviously fill the role of landing on amphibious assault ships. But it can fill Airforce and navy roles better.

 

[TaiidanTomcat]

What would have happened if the marines made do with STOL? How would the plane change if the requirements were modified for no hovering from the beginning? Could that F-35 adequately fill the role assigned to the current F-35B?

No.

 

[SlowMan]

What would have happened if the marines made do with STOL? How would the plane change if the requirements were modified for no hovering from the beginning? Could that F-35 adequately fill the role assigned to the current F-35B?

Well, the resulting jet would have to take off and land within a 200 m distance with no arrest wires. This may be achievable, but the jet must be a Gripen style Eurocanard with thrust vectoring.

I suspect the following would have been the result:

1. Engine would be moved further back in the fuselage because these is no more requirement for the nozzle to be closer to center of gravity during hover

2. Moving the engine back would release the need to wrap the back ends of the weapon bay around the fan casing. So that might either make the fuselage slimmer, or make room for the main landing gear to fit inside the fuselage instead of in bulges under the wing. Either way the drag characteristics of the plane should improve.

3. The shaping of the fuselage behind the cockpit was originally dictated by the desire to fit the large lift fan in the B version while preserving a common stealth shape factor for all three versions. Eliminating lift fan would facilitate lower hump behind the fuselage and potentially better all round cockpit visibility.

4. The elimination of stvol requirement would also remove the requirement for the bulky, stvol suitable ejection seat. This ejection seat is also disliked for blocking rear vision.

What you are suggesting is a totally new airframe.

 

[TaiidanTomcat]

4. The elimination of stvol requirement would also remove the requirement for the bulky, stvol suitable ejection seat. This ejection seat is also disliked for blocking rear vision.

According to Martin Baker:

The System Development & Demonstration (SDD) Ejection Seat that was selected by Lockheed Martin Aeronautics Company is a further development of the Mk.16 range that has already been successful with the T-6 Texan II, Eurofighter Typhoon, NASA T-38N and USAF T-38 upgrade programmes and other numerous aircraft platforms around the world.

The US16E Ejection Seat provides an unprecedented balanced optimisation between key performance parameters such as safe terrain clearance limits, physiological loading limits, pilot boarding mass and anthropometric accommodation ranges to fully meet the F-35 Escape System requirements. The US16E will be common to all F-35 aircraft variants.

The US16E is the only Qualified Ejection Seat that meets the US Government defined Neck Injury Criteria (NIC) across the pilot accommodation range.


The only difference with the STOVL version of the seat is the Auto-Eject feature, and I think the big head rest has more to do with the neck protection, than the STOVL requirements:

http://sitelife.aviationweek.com/ver1.0/Content/images/store/3/12/b38fce91-a7ab-4d77-9cb0-1b25ab43a68c.Full.jpg

I could be wrong though.

The USN version could also be faster if we waived its requirement to land on an aircraft carrier. Also General Bogdan already dismissed the complaint of poor rearward vis, saying that DAS made it a non-issue.

But it can fill Airforce and navy roles better.

You mean with less drag? "better" is a bit dubious to me. The point of the F-35 wasn't to create Raptor Jr.

 

[Avimimus]

It is an interesting question though - how far can you push a single engined fighter (performance wise) at the cost of all else.
I'm sure there are a number of relevant studies.

 

[Sundog]

Well, the resulting jet would have to take off and land within a 200 m distance with no arrest wires. This may be achievable, but the jet must be a Gripen style Eurocanard with thrust vectoring.

This is patently false. The X-32, for all practical purposes, was a STOL aircraft and did not have a canard. Anyone who thinks STOL requires a canard understands neither canards nor STOL aerodynamics, regardless if it is a powered STOL aircraft or purely aerodynamic. Some times a canard makes sense and some times it doesn't. It all depends on how the requirements are written over the entire envelope.

 

[SlowMan]

This is patently false. The X-32, for all practical purposes, was a STOL aircraft and did not have a canard.

Well, you are missing the context of the debate.

What would have happened if the marines made do with STOL? How would the plane change if the requirements were modified for no hovering from the beginning? Could that F-35 adequately fill the role assigned to the current F-35B?

Well, the resulting jet would have to take off and land within a 200 m distance with no arrest wires. This may be achievable, but the jet must be a Gripen style Eurocanard with thrust vectoring.

Anyone who thinks STOL requires a canard understands neither canards nor STOL aerodynamics, regardless if it is a powered STOL aircraft or purely aerodynamic.

F-15 STOL

Su-33 STOBAR

Both were non-canard jets that gained canards for the specific purpose of STOL.

 

[SlowMan]

It is an interesting question though - how far can you push a single engined fighter (performance wise) at the cost of all else.
I'm sure there are a number of relevant studies.

Well, the imagine what an F119 powered F-16XL would be like. Maybe you could add canards or horizontal tails to F-16XL to improve turn performance.

 

[Sundog]

Having studied and written code for STOL aerodynamics, there's more to it than what you show. Go look at the STOL F/A-18, it didn't have canards, or the SAAB 2107, which was the leading design for what would become the Gripen, but they thought the dorsal inlet was too risky, it didn't have canards. Having said that, none of the Euro-Canards are true STOL. As I said in my original response, it depends on the requirements.

Something you should note, canards don't really offer any advantage in STOL if you have thrust vectoring. In fact, in some ways TV is better than canards for STOL, because you can rotate earlier than you could with a canard, unless the canard is over-sized, which would be really bad for the rest of the flight envelope. TV allows a plane to rotate at a lower speed to get the wing to a higher alpha earlier than you can with a typical canard.

You should also note that the Flanker is not a STOL aircraft and the newest versions, with TV, don't have canards.

 

[chuck4]

I think the notion that canard aids in STOL is likely a legacy of the Viggen, arguably the first high performance STOL jet fighter to see service. But in its case the canard is fixed, and designed to function as a flow control device for the main wing.