Where Tejas falls behind

[SQ8]

LCA has almost 90% identical wing area to that of SAAB viggen.

The Viggen had a very straightforward level compound delta, while the Tejas has the more refined version..
However, it is not the first fighter to employ the differential wing dihedral/anhedral concept.

 

[acetophenol]

The Viggen had a very straightforward level compound delta, while the Tejas has the more refined version..
However, it is not the first fighter to employ the differential wing dihedral/anhedral concept.

Oscarji,can you give me an answer for my endurance question?

 

[Irfan Baloch]

LCA is not the first to have a cranked Delta wing.

interesting picture

thanks Ramu.


the design is not common I must say. looks like one of the NASA's research & experimental planes

F-16 XL?

the question remains from my side. why this design for an aircraft that is rolled in for induction in IAF. what are the percieved advantaged and whats the trade off compared to contemporary delta design of say Mirages

LCA has a very bad aspect ratio..
It's major flaw is it produces less lift in relation to drag

please elaborate how aspect ratio is bad?

I thought that huge wing was meant for extra lift.

 

[Manticore]

http://dc314.*******.com/img/qyCgGV6W/0.5962879171921205/Mirage-family-profile_2.jpghttp://dc314.*******.com/img/-PZFsfrn/0.5078734194759144/Dassault_Mirage_Variants_Page_.jpghttp://dc302.*******.com/img/Jznq6dD3/0.22460582083015224/Mirage_III-5_Risszeichnung.png

http://dc302.*******.com/img/L4daVbPu/0.6621893016086935/DASSAULT-BREGUET_MIRAGE_F1.pnghttp://dc302.*******.com/img/QqcDqrWm/0.3226405605911671/mirage4000.jpghttp://dc302.*******.com/img/LXyy0g_L/0.15700713298832647/mirage2000_schem_01.gifhttp://dc302.*******.com/img/aBAuddUP/0.7954837414867668/dassault_mirage4.gif

mirage family
.......................................................................................

 

[Manticore]

http://dc302.*******.com/img/VxT0FhMW/0.7962529044183803/avmir3_7.gifhttp://dc302.*******.com/img/Srpo9Fm4/0.949443410761101/l0218.jpghttp://dc299.*******.com/img/KiWfNBQY/0.7764493996990253/IAI_NAMMER.JPG


L]

kifir nammer cheetah

.........................................................................

http://dc312.*******.com/img/7K6MVDzu/0.6348326625957622/TejasGripen.jpg

eygypt-- HA-300 -- 3 prototypes in 1970s [compare to mirage3/5]

F-102

 

[Manticore]

lca still is based on a primitive tailess delta design with levcons

ive posted 25+ fighters in this category starting from

primitive tailless delta- m2k/mirage3/5 , nammer, kifir[experimented with a small fixed canard type],cheetah, eygptian, lca , f102, f106

XF-92 [1945]

then compound delta [without seperate canards]mig21 prototypes, f16xl-, draken, f108

cranked delta- like f7pg

then viggen came up with a fixed canard +delta

latest fighters now have moveable canards- j10 etc

--------------------------------------------------------

 

[Manticore]

pakfa and lca use LEVCONS and give a controlled lift and vortex generation in the front

http://www.defence.pk/forums/air-warfare/75408-combat-aircraft-projects-designs-index-2nd-post.html
http://www.defence.pk/forums/air-wa...aracteristics-canard-non-canard-fighters.html

 

[Irfan Baloch]

Oscarji,can you give me an answer for my endurance question?

I guess you should look out for Tejas information pool for that information. its internal fuel capacity is reported to be 2400+ kg and a range of 850 km. no figures on loitering time.

but the discussion here is mainly on its uncommon design and what are the trade-offs

which so far I have learnt to be
it is intended for interception mainly
& maneuverability and turning has been sacrificed

 

[Windjammer]

interesting picture

thanks Ramu.


the design is not common I must say. looks like one of the NASA's experimental planes

which one is it?

Once purposed F-16XL, there were then suggestions that it may replace the F-15 Eagle.

 

[BlueDot_in_Space]

it is intended for interception mainly
& maneuverability and turning has been sacrificed

Maneuverability and turning has been enhanced by adopting relaxed static stability (RSS), i.e., unstable design. Sustained turn rate has been improved by adopting the cranked (not an apt word) design. RSS also improves lift and reduces drag both in subsonic and supersonic speeds.

Advantages of F16XL's cranked arrow delta wing over F16 : In XL, the wing and rear horizontal control surfaces were replaced with a cranked-arrow delta wing 120% larger than the original wing. These changes resulted in a 25% improvement in maximum lift-to-drag ratio in supersonic flight and 11% in subsonic flight, and a plane that reportedly handled much smoother at high speeds and low altitudes. The enlargements increased fuel capacity by 82%. The F-16XL could carry twice the ordnance of the F-16 and deliver it 40% further. The enlarged wing allowed a total of 27 hardpoints. (source:wiki)

 

[BlueDot_in_Space]

LCA is not the first to have a cranked Delta wing.

Tejas wing design is opposite of F16XLs design as shown in the Figure below. Tejas leading edge is low sweep, where as in XL its high sweep

Also,the design of Tejas is called compound delta, while that of XL is called cranked arrow. Tejas has a compound delta wing design with a unique low sweep leading edge crank. This crank is different from that of XLs. Tejas crank is only visible in the side view.

 

[MilSpec]

Tejas wing design is opposite of F16XLs design as shown in the Figure below. Tejas leading edge is low sweep, where as in XL its high sweep

Also,the design of Tejas is called compound delta, while that of XL is called cranked arrow. Tejas has a compound delta wing design with a unique low sweep leading edge crank. This crank is different from that of XLs. Tejas crank is only visible in the side view.

Very true
.
There is a confusion regarding the tejas wing, Tejas indeed has a compound delta planform (which sometimes is referred as the cranked double delta or compound delta or compound arrow) but the crank - compound delta planiform actually refers to the upward cranked tips, the tip section dihedral differs from the main section. The configuration is useful for achieving lateral instability. This crank kind of negates the use of control canards partially and lifting canards to a larger extent. If you imagine a longer fuselage at the nose section, you can very easily imagine and trace a similar profile to f16XL. Also the wing loading on the Tejas is low hence there isn't much of the need for lifting canards

 

[Manticore]

What went wrong with LCA, Arjun Tank, Akash missile
Manu Pubby : New Delhi, Tue Mar 03 2009

What went wrong with LCA, Arjun Tank, Akash missile - Indian Express

 

[janon]

What went wrong with LCA, Arjun Tank, Akash missile
Manu Pubby : New Delhi, Tue Mar 03 2009

What went wrong with LCA, Arjun Tank, Akash missile - Indian Express

That's a very old article. The Arjun and Akash have been successfully inducted into the forces since it was written. The Arjun has outperformed the T-90, and Akash SAMs have an order book of several billion dollars. Two regiments of Akash SAMs have already been inducted by the IAF, with more to follow. One regiment of Arjun tanks (or is it two?) are already in service, and India's future MBTs will all be future variants of Arjuns.

Unfortunately, the delays in the LCA program are still continuing, and although the LCA has evolved since then, its FOC still remains painfully elusive.

 

[Mian H Amin.]

what do you mean ? arent the gona fight in case of war ??? lol