Tejas FOC : Miles to go

[Dillinger]

No No! FCS and engine. UCAVs are example. For manned would require complex FCS

UCAVS are not tier one fighters/interceptors nor are we dealing with a platform tailored along the ubiquitous flying wing design (which is what the majority of sophisticated UCAVs comply too, AURA/TARANIS/RQ-170/NEURON/X-47B, the said design intentionally calls for the absence of a "fin"). You are making the same mistake in your notions as the ADA did in its days of designing the Tejas, the demands made on a manned fighter which is to see combat while generating a high sortie rate in a non-permissive environment are very different from those made upon science projects and demonstrators. Flight profile characteristics of a needlessly complicated design do not lend themselves to margins of error. Part of the reason why the early tailless and absent vertical stabilizer (fin) design of the MCA was dropped quite quickly.

 

[Bhasad Singh Mundi]

......

First you said twin engine is a requirement so its not possible in Tejas. Now you are saying its complex design so not possible in real world scenario. I think you should stick with one line of argument.
Technically its very much possible to convert Tejas into a fin less plane with thrust vectoring. But as of now, ADA does not have such experience of complex FCS design (that's why no stall and spin tests for Tejas so far because it involves non linear aerodynamics, although they are developing the required models). Within one and half decade, hope to see such maturity level reached by ADA in FCS and thrust vectoring algorithms.

 

[Dillinger]

First you said twin engine is a requirement so its not possible in Tejas. Now you are saying its complex design so not possible in real world scenario. I think you should stick with one line of argument.
Technically its very much possible to convert Tejas into a fin less plane with thrust vectoring. But as of now, ADA does not have such experience of complex FCS design (that's why no stall and spin tests for Tejas so far because it involves non linear aerodynamics, although they are developing the required models). Within one and half decade, hope to see such maturity level reached by ADA in FCS and thrust vectoring algorithms.

And you missed the point. Let me clarify for your benefit. A single engined platform does not lend itself to a complex and hitherto un-tested (non-operational) design ergo under "real world" conditions (that is to say while keeping the operational realities faced by the IAF in mind) such a design choice would only be remotely feasible on a more robust twin-engined fighter. That having been said even then the novelty of the design will still not provide any spectacular return as opposed to the costs imposed. I ventured to address two different yet inter-connected facets in two separate posts in order to aid comprehension and to further furnish my assertion in the face of your post. Collating the data provided in both my posts and thereby constructing a cogent narrative could not have been that difficult.

Now do me a favor, exhibit a cranked delta wing UCAV design sans vertical stabilizers.

 

[Superboy]

Designs will be finalized next month. We can construct one plane by early 2015. Ground test for 3 month and flight by June 2015.

If DRDO do not become complacent and work hard as they did in IOC 2, It seems very much feasible.

That would be preliminary design finalized by next month. It takes at least a year to two to produce the final design. Mk 2 won't fly before mid 2017.

Tejas Mk-II Preliminary Design to be Out Next Month -The New Indian Express

 

[Dillinger]

@sandy_3126 Not that this is part of the topic but the recent decision to have separate integrating and designing agencies for the civilian airliner reminded me of our issues with the Tejas program.

 

[MilSpec]

First you said twin engine is a requirement so its not possible in Tejas. Now you are saying its complex design so not possible in real world scenario. I think you should stick with one line of argument.
Technically its very much possible to convert Tejas into a fin less plane with thrust vectoring. But as of now, ADA does not have such experience of complex FCS design (that's why no stall and spin tests for Tejas so far because it involves non linear aerodynamics, although they are developing the required models). Within one and half decade, hope to see such maturity level reached by ADA in FCS and thrust vectoring algorithms.

Thrust vectoring algorithms.... interesting.. please elaborate.

@sandy_3126 Not that this is part of the topic but the recent decision to have separate integrating and designing agencies for the civilian airliner reminded me of our issues with the Tejas program.

you know this thread is a prime example how we discuss the same topics over and over again.... questions rhetorics and arrogance remains the same , just faces change!

 

[Bhasad Singh Mundi]

And you missed the point. Let me clarify for your benefit. A single engined platform does not lend itself to a complex and hitherto un-tested (non-operational) design ergo under "real world" conditions (that is to say while keeping the operational realities faced by the IAF in mind) such a design choice would only be remotely feasible on a more robust twin-engined fighter.

Then what is F16? the first operational unstable fighter with single engine and complex digital FBW FCS == complex and hitherto un-tested (non-operational) design in your language for its time. novelty of the design that provided spectacular returns. Taranis is a delta wing UCAV if you dont know.

Thrust vectoring algorithms.... interesting.. please elaborate.


you know this thread is a prime example how we discuss the same topics over and over again.... questions rhetorics and arrogance remains the same , just faces change!

am i showing you arrogance? I am talking about possibilities one and half decades from now, is that arrogance? strange.

 

[MilSpec]

Then what is F16? the first operational unstable fighter with single engine and complex digital FBW FCS == complex and hitherto un-tested (non-operational) design in your language for its time. novelty of the design that provided spectacular returns. Taranis is a delta wing UCAV if you dont know.



am i showing you arrogance? I am talking about possibilities one and half decades from now, is that arrogance? strange.

that wasn't meant for you, it was a general observation from the tone of the thread.... but please do elaborate on thrust vectoring algorithm... I would like to know more

 

[Bhasad Singh Mundi]

that wasn't meant for you, it was a general observation from the tone of the thread.... but please do elaborate on thrust vectoring algorithm... I would like to know more

algorithms to schedule the pitch and yaw vectoring to provide control in the absence of fin or vertical stabilizers

 

[MilSpec]

algorithms to schedule the pitch and yaw vectoring to provide control in the absence of fin or vertical stabilizers

Which will compensate for radial axis in yaw on available flight surface, and also equalize thrust response in lieu of differential barometric pressure drop at given altitude... I pity the groups tasked to do this.

 

[Superboy]

-3g to 8g maneuverability, same as that of JF-17? Tejas Mk 2 and Block 3 JFT are slated to be powered by powerful 22,000+ pounds F414 / WS-13A giving supercruise capability and also AESA.

 

[Bhasad Singh Mundi]

Which will compensate for radial axis in yaw on available flight surface, and also equalize thrust response in lieu of differential barometric pressure drop at given altitude... I pity the groups tasked to do this.

How do you think UCAVs fly without vertical stabilizers?

 

[Dillinger]

Then what is F16? the first operational unstable fighter with single engine and complex digital FBW FCS == complex and hitherto un-tested (non-operational) design in your language for its time. novelty of the design that provided spectacular returns. Taranis is a delta wing UCAV if you dont know.



am i showing you arrogance? I am talking about possibilities one and half decades from now, is that arrogance? strange.

Have I asserted that you are arrogant?


BAE Taranis is a flying wing platform optimized for long endurance LO. There is a difference between a flying wing design and a delta wing design. Some other UCAVs happen to be blended body platforms ergo not pure flying wings.


The F-16 was built upon a lineage of systems tested across the years in conjunction or isolation. For example the digital FBW was rigorously tested on the F-8C crusader (also a single engined platform), a tried and tested platform which had been operational for a very long time in 72 a full 2 years before the 16s ever took flight. Again, you are missing the point, it is not as if the laws of physics disallow what your are envisioning form coming true but rather our own design considerations which are dictated by operational requirements. So no, nothing that novel or earth shattering feature on the Falcon was untested.

 

[Superboy]

IMO Tejas and JF-17 are very agile planes given their relaxed stability design due to for example relatively small vertical stabilizers. 8g is not bad, but 9g would have been optimal. Anyone know the g numbers of say F-5 and MiG-21?

 

[Dillinger]

How do you think UCAVs fly without vertical stabilizers?

Because the UCAVs in question are flying wing designs.

BAE TARANIS-

RQ-170:-

A flying wing design does not necessitate a vertical stabilizer.


UCAVs which don't belong to the flying wing family have vertical stabilizers.

Oh and the above design choice always leads to sacrificing maneuverability, forget high-g combat or instantaneous turn rate figures which make a jet a true fighter.