article in the Deccan Chronicle, dated 29 May, 2008

Bangalore, May 28: The Light Combat Aircraft Tejas is set to undergo hot weather trials in Nagpur. This is a significant step for those involved with the project, which has to obtain Initial Operational Clearance in mid-2010. Speaking to this correspondent, Dr. P.S. Subramanyam, the LCA project director, explained the importance of the projects and the difficulties it faced.

Now, with the finish line in sight, Dr Subramanyam exulted: “This country has never failed in anything, be it nuclear weapons, missiles, supercomputers.” Speaking about the hot weather trials which are expected to be held before the month-end or early June, Dr Subramanyam said, “The Nagpur trials are to see how the aircraft and its subsystems work in hot weather conditions. We expect to experience an ambient temperature of 45º Centigrade and characterise the aircraft.”

In August-September, the aircraft will be taken to Jaisalmer for weapon trials. The cold weather trials will be done next year. Answering questions about delays and cost overruns, Dr Subramanyam charted the course of the project. “It was first proposed in 1983, but the Aeronautical Development Agency (ADA) itself came into existence only in 1985. And, we had three people then. Initial activity started in 1986 when ADA was given a small corner in the National Aeronautical Laboratory,” he said.

In 1987-88, Dassault of France was commissioned to do preliminary feasibility studies. “It was only in 1989 that we came to understand what the project entailed.” “We gave our report to the government, and said we would need to produce seven aircraft to complete the programme. The government said just build two technology demonstrators,” he said. “It was then considered nothing more than an engineering project. Even money for phase one of the full-scale engineering project was given in 1993.”

The technology development included development of a fly-by-wire system, real-time embedded controllers and other sub-systems. “We completed that programme in 2004. The real kick-off for operational fighter aircraft was given only in 2001, after the first flight test that year.” “If you consider this timeline, the progress of the LCA project is comparable to any other fighter jet project around the world,” Dr Subramahyam said.

When the project started, “our technology was stencil drawings, while other countries had advanced technology. We did not even have computers to work on, let alone CAD/CAM software,” he said. “We did not have the human resources, we did not have the design tools, and we did not have the test facilities. All of them had to be evolved.” Today, six aircraft have done 870 flights. There is still painstaking work to be done on the ‘angle of attack’. The LCA hs reached 20 degrees against 22 degrees required for highest performance.

“The flying machine is ready. We are building the fighting machine,” Dr Subramahyam said. “We are doing the sensor-weapon integration, and we are 80 per cent through.”

just for starters, the RD-33’s dimensions don’t match those of the F-404 or Kaveri. so, for hardly any thrust gain, too much work to be done to redesign the Tejas to accomodate the RD-33. so, the F-414 would be a better match.

RD-33 specs:
Length: 4,250 mm (167.3 in)
Diameter: 1,040 mm (40.9 in)
Dry weight: 1,055 kg (2,325 lb)
Thrust-to-weight ratio: 77.1 N/kg (7.9:1)

F-404 specs:
Length: 154 in (3,912 mm)
Diameter: 35 in (889 mm)
Dry weight: 2,282 lb (1,036 kg)
Thrust-to-weight ratio: 7.8:1 (76.0 N/kg) (for the F-404 GE402, not the IN20, which has higher thrust. source:link)

Thanks for sharing that. So after the viggen wing design, it seems the swedes were clear they were moving away from the pronounced crank in the wing.
Any info on what role Dassault had in the choice of the current wing shape for the LCA?

but the Viggen was still a canard-delta wing design, even though the canards did’nt perform much as compared to new generation canard delta aircraft. the Swedes never did have a pure compound delta wing with no canards.

No, as shown a similar configuration was explored by the Eurofighter consortium and ultimately rejected. In aviation, very few concepts are entirely unique.

actually, the last two designs shown in the figure you posted are more like the F-16XL than the Tejas. there is a compound cranking of the delta, and even near the wingtip, the sweep again reduces. in the Tejas, the wing tip is cut short, instead of having a lower sweep angle.

The current crank in the LCAs wing is fixed as well and given that neither dassault nor BAe nor LM nor Sukhoi chose the cranked delta of the shape used by the LCA says something about the viability of this configuration. Did they consider the LCA wing shape and reject it due to drag? Any independent studies out there on the LCA wing shape would be interesting to look at.

another thing- NAL did initially study the canard delta configuration and there was an image floating around the net that showed a wind-tunnel model at NAL which showed this. However, after Dassault was chosen as the design consultant, the design was frozen without any canards and the new wing shape was chosen.

by that time, Dassault was well into final design of the Rafale. Saab had only considered the canard-delta configuration for the Gripen. There was another great image that showed all the various configs that Saab had tested out before finally arriving at the Gripen shape config we see today.

The LCA has a far greater wing area than either the Gripen or T-50. Low wing loading might be beneficial in terms of maneuverability or airfield performance, but it is entirely detrimental in terms of drag. Keep in mind that the LCA stems from the same BAe P.106B study as the Gripen, but after Dassault’s entry into the program, the configuration increase in wing area and dropped the canards. My guess is that the canard was dropped to reduce production costs while the increase in wing area was meant to offset the loss of the canard.

the canard’s role was to be performed by the compound cranked delta wing. that increased the wing area and lowered the wing-loading, meaning that as a fighter, the Tejas would be nimbler.

in fact, studies that were conducted on the Naval LCA concluded that there was no need for the nose mounted strakes or small canards that were initially considered useful for low speed flight during landing phase. the same job could be performed by LEVCONS instead, which are located at the root of the wing, where the sweep is lesser than that of the rest of the wing.

so they’re getting 24 brand new F-16 Blk 50/52s and 24 second hand F-16 Blk 25s that will be upgraded? how many Lancers does Romania operate and look to replace with these fighters ? I feel that the Gripen C/D would be a better option for Romania than crash prone F-16s. was’nt the Gripen also in the race for their fighter replacement?