Thrust Vectoring

[Todjaeger]

Thanks to everyone who have posted to my thread (except milli). What is the biggest disadvantage in adding thrust vectoring. In other words, why not?

Is it costs, weight, or wear n tear.

I'm sure its all 3 but what would be number 1?

When I look at the F 22's nozzles, I see it adding to its stealthy design. I believe there are heat absorbing materials in the vector nozzles to reduce the fighter's Infrared Signature as well. Finally, there is added maneuverability if it is needed. So again, why not?

The F 35's nozzle looks like a giant, well rounded, fire pit.

I believe the F 35 would have greatly benefited from having the F 22's thrust vectoring nozzle design for these reasons. Better stealth, better IR signature, and better maneuverability.

The Lockheed guys know what they are doing, so I'm going to guess costs.

The F-22's nozzles were designed to be LO, in addition to thrust vectoring, and the F-35's nozzle was similarly also designed to be LO, but without the additional requirement of being thrust vectoring. Now I admit that I am not an aerospace engineer, but I would expect that a LO-only nozzle would be easier to design and produce than a nozzle that was both LO and thrust vectoring. After all, why go to the extra effort to ensure that the LO capability meets whatever specification is required regardless of the position in thrust vectoring if one does not have to?

 

[OPSSG]

The F-22's nozzles were designed to be LO, in addition to thrust vectoring, and the F-35's nozzle was similarly also designed to be LO, but without the additional requirement of being thrust vectoring. Now I admit that I am not an aerospace engineer, but I would expect that a LO-only nozzle would be easier to design and produce than a nozzle that was both LO and thrust vectoring. After all, why go to the extra effort to ensure that the LO capability meets whatever specification is required regardless of the position in thrust vectoring if one does not have to?

Plus in the F-35B, the lifting/propulsion system has a three-bearing swivel module. The three-bearing swivel module is in effect a thrust vectoring nozzle at the tail of the aircraft used for certain modes in take-off and landing.

Nothing simple about fitting thrust vectoring to an already in service airframe and engine combo that was not designed for that.

Why would the designers/developers want TVC for slow speed turns in all models from A to C, when it is more important to swivel the nozzle for the B’s STOVL capability? I hope you realise the B model can swivel it’s nozzle — therefore, it is possible to argue that F-35B is designed for TVC, in STOVL modes of operation. The Rolls-Royce LiftSystem in the F-35B comprises four major components:

• LiftFan
• Engine to fan driveshaft
• Three-bearing swivel module
• Roll posts

The weight penalty of TVC would’ve been enough to see it cut at the design stage.

Just a thought bubble, the other issue would be graceful failure on a single engine jet. I know that modern turbines are highly reliable, but the last thing you’d want is the TVC stuck in a position where it is constantly inducing yaw or pitch. It’d be very easy for this to lead to an unrecoverable position.

In addition, the F-35B’s added LiftSystem components are dead weight during flight, but the advantage of employing the LiftSystem is that its greater lift thrust increases takeoff payload by an even larger amount.

 

[nightsight971]

Plus in the F-35B, the lifting/propulsion system has a three-bearing swivel module. The three-bearing swivel module is in effect a thrust vectoring nozzle at the tail of the aircraft used for certain modes in take-off and landing.

Why would the designers/developers want TVC for slow speed turns in all models from A to C, when it is more important to swivel the nozzle for the B’s STOVL capability? I hope you realise the B model can swivel it’s nozzle — therefore, it is possible to argue that F-35B is designed for TVC, in STOVL modes of operation. The Rolls-Royce LiftSystem in the F-35B comprises four major components:

• LiftFan
• Engine to fan driveshaft
• Three-bearing swivel module
• Roll posts

In addition, the F-35B’s added LiftSystem components are dead weight during flight, but the advantage of employing the LiftSystem is that its greater lift thrust increases takeoff payload by an even larger amount.

Actually I cut and pasted wrong, "Nothing simple about fitting thrust vectoring to an already in service airframe and engine combo that was not designed for that" belongs to todjaeger from earlier. Sorry.

But yes I agree, the F22 nozzle would be bad for the B model.

 

[Feanor]

Allegedly the first Chinese J-10B and J-20 with thrust vectoring engines flew recently. Whatever the opinions are on their practical utility, considerable resources are still being expended on the production and development of these engines.

Первые китайские серийные истребители J-10B и J-20 с двигателями с управляемым вектором тяги WS-10B

 

[Todjaeger]

Allegedly the first Chinese J-10B and J-20 with thrust vectoring engines flew recently. Whatever the opinions are on their practical utility, considerable resources are still being expended on the production and development of these engines.

Первые китайские серийные истребители J-10B и J-20 с двигателями с управляемым вектором тяги WS-10B

One also needs to consider the battlesystem construct which the PLAAF operates with. Do the fighters the PLAAF operate now, and are expected to operate in the near term have HOBS and LOAL capabilities? Also, does PLAAF doctrine and operational experience provide offboard sensor data? The impression that I have gotten is that the PRC realizes the importance of such capabilities, but is at least somewhat still in the stage of determining what fits their needs, before adopting a particular capability and then rolling it out to the force as a whole.

 

[Feanor]

One also needs to consider the battlesystem construct which the PLAAF operates with. Do the fighters the PLAAF operate now, and are expected to operate in the near term have HOBS and LOAL capabilities? Also, does PLAAF doctrine and operational experience provide offboard sensor data? The impression that I have gotten is that the PRC realizes the importance of such capabilities, but is at least somewhat still in the stage of determining what fits their needs, before adopting a particular capability and then rolling it out to the force as a whole.

Sometimes it does feel like the Chinese military in general is exploring every direction before committing. They do have impressive resources. Let's wait and see if this sees mass production. Though I suspect it will. They already operate the Su-35S with thrust vectoring.

 

[Boagrius]

I thought this was a good watch - a BFM matchup between a USN classic Hornet and a TVC equipped RMAF Su30MKM:

Note that even in the absence of TVC, the Hornet still excels in the low speed, high alpha domain. The use of TVC by the Flanker pilot at 12:30 sounds pretty spectacular though.

 

[JohnJT]

LM sweated blood trying to get the F-35's weight down. Some say it's still too heavy. Needless to say TVC was always a non-starter.

Besides, there's more than one way to skin a cat. The F-35's advanced flight control system constantly monitors the aerodynamic loading across the aircraft and through subtle constant adjusting of the control surfaces the flight computers can aerodynamically load or unload different parts of the aircraft. The results of this aerodynamic magic is that the F-35 is capable of impressive maneuvers without TVC.

 

[ngatimozart]

The F-35B has single axis thrust vectoring from 0° to ~ -90°.