HAL pegs price of Tejas fighter at Rs 162 crore

[SQ8]

@Oscar, could you tell us what is the article talking about.

The Tejas is more advanced in construction and all fly by wire. The rest of the advanced avionics is debatable.

 

[Superboy]

The Tejas is more advanced in construction and all fly by wire. The rest of the advanced avionics is debatable.

Super Hornet uses way less composites than Gripen does despite being almost a decade newer. Composites does not make a plane more advanced. It's structural design that mostly counts.

Tejas and JF-17 both have quadruplex digital FBW. I don't see how FBW can be used to make a point.

LCA Tejas - Technology: Fly by Wire

JF-17 Avionics | JF-17 Thunder

 

[SQ8]

Super Hornet uses way less composites than Gripen does despite being almost a decade newer. Composites does not make a plane more advanced. It's structural design that mostly counts.

Tejas and JF-17 both have quadruplex digital FBW. I don't see how FBW can be used to make a point.

LCA Tejas - Technology: Fly by Wire

JF-17 Avionics | JF-17 Thunder

The composites are not what is the advanced part.. its the construction techniques they allow that are.
Tejas is all FBW.. (although really that is a moot point). The JF is FBW in Pitch. Although in reality that only depends on the requirements stated. The avionics bit is all conjecture.

 

[Superboy]

The composites are not what is the advanced part.. its the construction techniques they allow that are.
Tejas is all FBW.. (although really that is a moot point). The JF is FBW in Pitch. Although in reality that only depends on the requirements stated. The avionics bit is all conjecture.

Where does it say Tejas fly by wire is full in all three axis roll, pitch, yaw?

FBW is not that important. None of America's F-15 have digital FBW.

 

[Armstrong]

The composites are not what is the advanced part.. its the construction techniques they allow that are.
Tejas is all FBW.. (although really that is a moot point). The JF is FBW in Pitch. Although in reality that only depends on the requirements stated. The avionics bit is all conjecture.

For those of us who don't know what the heck you're talking about with your acronyms & cryptic talk of 'better construction techniques' - How about some English ?

 

[SQ8]

Where does it say Tejas fly by wire is full in all three axis roll, pitch, yaw?

http://www.drdo.gov.in/drdo/pub/techfocus/2011/feb 2011 .pdf

 

[SQ8]

For those of us who don't know what the heck you're talking about with your acronyms & cryptic talk of 'better construction techniques' - How about some English ?

Composites allow for less pieces and hence less holes and screws to hold them together. With composites you can build much larger complex pieces without fear of them buckling under stress. Some metal alloys overcome this but bring with them weight as a penalty(although other metals such as titanium avoid this but are expensive).

The Tejas also uses Aluminium for its main rigidity like the JF-17.. but where possible uses composites save weight , including in the fuselage (doors and skins), wings (skin, spars and ribs), elevons, tailfin, rudder, air brakes and landing gear doors

LCA Tejas - Technology: Composite Materials

Although stating the brakes is pointless as most aircraft now use ceramic composite brakes including the JF-17.

Where does it say Tejas fly by wire is full in all three axis roll, pitch, yaw?

FBW is not that important. None of America's F-15 have digital FBW.

The newer F-15SA sold to Saudi Arabia have full FBW.

FBW is useful as it saves weight for one..For unstable aircraft.. it is a must. Since the F-16.. most combat aircraft are designed as inherently unstable. i.e.. they will want to go out of control and fall out of the sky without a computer constantly adjusting them. FBW also allows more precise control and easier flying characteristics of the aircraft, the F-15 for e.g. is a very touchy aircraft to fly... however the new F-15SA for Saudi Arabia with its full FBW is reportedly as easy as any trainer.

 

[Armstrong]

Composites allow for less pieces and hence less holes and screws to hold them together. With composites you can build much larger complex pieces without fear of them buckling under stress. Some metal alloys overcome this but bring with them weight as a penalty(although other metals such as titanium avoid this but are expensive).

The Tejas also uses Aluminium for its main rigidity like the JF-17.. but where possible uses composites save weight , including in the fuselage (doors and skins), wings (skin, spars and ribs), elevons, tailfin, rudder, air brakes and landing gear doors

LCA Tejas - Technology: Composite Materials

Although stating the brakes is pointless as most aircraft now use ceramic composite brakes including the JF-17.


The newer F-15SA sold to Saudi Arabia have full FBW.

FBW is useful as it saves weight for one..For unstable aircraft.. it is a must. Since the F-16.. most combat aircraft are designed as inherently unstable. i.e.. they will want to go out of control and fall out of the sky without a computer constantly adjusting them. FBW also allows more precise control and easier flying characteristics of the aircraft, the F-15 for e.g. is a very touchy aircraft to fly... however the new F-15SA for Saudi Arabia with its full FBW is reportedly as easy as any trainer.

Why didn't we go for more Composites then & would it be possible to go for more Composite inclusion if we go for a Block 4 or 5 later on ?

 

[nik22]

The composites are not what is the advanced part.. its the construction techniques they allow that are.
Tejas is all FBW.. (although really that is a moot point). The JF is FBW in Pitch. Although in reality that only depends on the requirements stated. The avionics bit is all conjecture.

Hi Oscar, what would you say just about design of both aircraft? Compound delta wing vs cropped-delta?
Do you mind doing a comparison like?
Basic design of both and comparison against current design philosophies to understand if that is relevant
Manufacturing pros, cons for both aircraft (something like what HAL can mess up and their counter part in Pakistan. Who can produce better aircraft?)
Current "perceived" status (not really a comparison. I think JF-17 is much ahead right now in terms of ope-rationalization. But some Indian members claim it is yet to get FOC?)
Future improvement scope.
Competitors

long list I guess

 

[Capt.Popeye]

http://www.drdo.gov.in/drdo/pub/techfocus/2011/feb 2011 .pdf

@Oscar; its good to see that you are one the (few) posters posting some credible information here. What a contrast from posters like the kind of @Deserted Fighter and some of the the other assorted snotties, just taking some "dumps" here since they simply have the "untramelled freedom" to post here...............never mind if its the most irrelevant cr@p.

 

[SQ8]

Why didn't we go for more Composites then & would it be possible to go for more Composite inclusion if we go for a Block 4 or 5 later on ?

That has already been debated during design. The usage of composites would increase the cost of the aircraft(as there would need to be redesign, retesting and a new manufacturing process)

 

[Armstrong]

That has already been debated during design. The usage of composites would increase the cost of the aircraft(as there would need to be redesign, retesting and a new manufacturing process)

But wouldn't that also prolong the life of the aircraft as an upgradeable platform as opposed to one which, perhaps in the next 20 years, becomes obsolete due to its inability to incorporate a heavier weapons or avionics package due to weight limitations ?

 

[Superboy]

The composites are not what is the advanced part.. its the construction techniques they allow that are.
Tejas is all FBW.. (although really that is a moot point). The JF is FBW in Pitch. Although in reality that only depends on the requirements stated. The avionics bit is all conjecture.

JF-17 performance in Dubai air show demonstrates it has FBW in roll. That's why it can fly upside down sustained.

JF-17 uses the same FBW as J-10, so I don't see how it could not be full in pitch, roll, yaw.

 

[SQ8]

Hi Oscar, what would you say just about design of both aircraft? Compound delta wing vs cropped-delta?
Do you mind doing a comparison like?
Basic design of both and comparison against current design philosophies to understand if that is relevant
Manufacturing pros, cons for both aircraft (something like what HAL can mess up and their counter part in Pakistan. Who can produce better aircraft?)
Current "perceived" status (not really a comparison. I think JF-17 is much ahead right now in terms of ope-rationalization. But some Indian members claim it is yet to get FOC?)
Future improvement scope.
Competitors

long list I guess

Ill keep this short as it has been answered well(with regards to Tejas) by certain Indian members who are part of the Analyst team at PDF. Namely sancho and Sandy.. please look up their posts for the most accurate and unbiased information on the type.

The JF-17 is a fairly standard triplane design with cropped delta and large LERX. This affords it good instantaneous turn rate( right when the pilot pulls the stick) and a very good sustained rate(When the pilot continues pulling the stick) even at high angles of attack(nose pointing up).

The Tejas's cropped delta with its pitch instability gives it an excellent instantaneous rate but an average sustained rate.. It has however have good nose pointing abilities much like the JF-17 and the F/A-18 at high angles of attack.

The Jf-17 has comparable roll rates to the F-16.. the Tejas has higher roll rates due to its smaller planform and the benefit of the "delta" only design.

Ive posted this before elsewhere. If both aircraft go head to head.. the Tejas will be able to point its nose at the JF-17 first. If the Tejas does not kill the JF-17 in its first attempt.. the JF-17 will fly circles around it and kill it(if there are pilots of equal calibre in the aircraft). The Tejas Mk-II with the LEVCONs will supposedly improve the sustained rate and largely negate the difference in a close fight provided that the LEVCONs work as advertised.

Both aircraft have room for growth but the Tejas has more growth potential in terms of fuel and payload capacity.
The Tejas's structural changes will cost more than the JF-17 but will add less penalties in terms of weight.

Both aircraft have ownership to their respective nations and hence are not bound too much by any international relationship hurdles. The tejas more so as the Indian avionics and aircraft manufacturing industry is moving faster than its Pakistani counterpart.

The JF-17 has FOC and is now operating on Quick reaction alert duties with full A2A capability( an interview is available in the JF-17 thread for reference). FoC means the aircraft is ready to go to war in sufficient numbers with confidence.. and the JF-17 is very ready for war.

The Tejas has just gone through IoC.. which means that it is going to operational squadrons now where new tactics and training for the aircraft will be developed. ..and a final squadron of aircraft that needs to be made ready.. equipped with these tactics and procedures(including the ground crew training). Once that happens, the Tejas too will achieve FoC.

Both the aircraft will continue to have multiple IoC with weapons throughout their lives. The Tejas has IoC with the R-74 and LGBs..
The JF-17 has FoC with the PL-5E-II and SD-10. So yes the JF-17 program is ahead.. but that owes a lot to the horrendous development delays in the LCA program.

 

[SQ8]

JF-17 performance in Dubai air show demonstrates it has FBW in roll. That's why it can fly upside down sustained.
JF-17 uses the same FBW as J-10, so I don't see how it could not be full in pitch, roll, yaw.

Read a little bit more into aviation and you will see why that is a VERY bad statement to make to try and prove something. The F-15 has been doing that without FBW since 1970. The JF-17 has a computerized Stability augmentation system for its roll and yaw axis that coordinates with the FBW in pitch. Hence the pilot can roll it upside down.. and the aircraft will not roll here and there without external interference.

The J-10 uses a different FBW system. Different design. To satisfy your persistance, I suggest you read up on the interview of JF-17 project here.
https://dl.dropboxusercontent.com/u/81032936/JFT_Article.pdf

Where Mr Zhu Zheng says clearly that it is FBW in Pitch and mechanical in roll and yaw.

@Oscar; its good to see that you are one the (few) posters posting some credible information here. What a contrast from posters like the kind of @Deserted Fighter and some of the the other assorted snotties, just taking some "dumps" here since they simply have the "untramelled freedom" to post here...............never mind if its the most irrelevant cr@p.

There are similar Indian members who do the same in the JF-17 thread. We have Indian members taking off their glasses of patriotism and jingoism in the JF-17 thread too. So they are appreciated there as well.