Why would HAL set up a larger assembly line unless they can get firm orders from their one and only customer? If IAF only intends to place orders for 40 Tejas Mk1, HAL will only set up an assembly line for 10.
Orders cannot be given until the design meets basic performance parameters.
In DRDO's own words http://www.drdo.gov.in/drdo/pub/dss/200 ... EMILAC.pdf
It is seen that most of the performance parameters are deviating from the requirements.
The Air brakes in Tejas provided at the rear spinal part of the fuselage to decelerate aircraft at higher speeds. Due to this rear location in addition to the deceleration it gives an uncommanded pitch up and directional stability reduction. Various improvement methods like perforated airbrake, updation of aero data set and fine tuning of control law gains were tried. Still the problem is not rectified completely.
Tejas airbrakes http://www.bharat-rakshak.com/media/Aer ... e.jpg.html
Sukhoi airbrakes http://www.flickr.com/photos/vishwak/5436297107/
mounted close to CoG, so no such moment arm acting on the aircraft. Mirage 2000 airbrakes are mounted on wing http://rafaleair.free.fr/photo2/mirage%202000-5%20F.jpg
close to CoG.
Common sense dictates such parts be close to CoG to minimize uncommanded movements. However, for reasons best known to designers, they didn’t. Simulation/Testing should have revealed this during design, but again, this went ahead.
F-16 has rear brakes, but they split open equalizing the force unlike the upward-only Tejas http://pafwallpapers.com/blog/wp-conten ... arrows.jpg
A study taken up to utilize the main landing gear follow up door as an airbrake.
So we’ll see a plane that’ll keep opening its MLG doors in flight.
One of the major out come of sea level trial of Tejas is that the drag of the aircraft is high such that the aircraft could not reach the supersonic Mach number at sea level.
Nose cone extension using a Plug.
Trailing Edge Extension (TEC)
Now this is interesting. Many BR members on seeing the abrupt training edge had commented that it would be draggy. http://imageshack.us/photo/my-images/88 ... 01is2.jpg/
Common Sense that airflow split at wing root leading edge should be enabled to rejoin at the wing root trailing edge.
From the Fig. 12 it is seen that there is a sudden variation in cross sectional area at the rear end of the fuselage also. This can be minimized by the modification in the trailing edge using TEC. Fig. 15 and Fig. 16 shows the rear fuselage before and after modification.
Again, why didn’t this come up during initial design/testing.
The fighter variant of Tejas is not meeting the STR requirement of ASR.
Atleast until 2009, there was no solution in place.
A detailed study to implement Levcon in fighter and identification of other design constraints is under progress.
IAF has valid reasons to describe Tejas as a deformed Cheetah. Despite that 40 planes have been ordered, that is 5.5% of its authorized fighter force. FWIW, I doubt IAF will ever deploy Mk 1 in air to air combat, risking the lives of the pilot without performance requirements being met. Also, with further design changes, manufacturing will be impacted.