The Tejas Tweets – Replies to Vina’s points Prof.Prodyut Das “Vina” has very kindly sent a set of points for discussions. I have already replied to them –literally off the cuff-on twitter but, seeing the interest generated, I felt that I should post it on blog as a more easily accessible record for future use. The link he refers to is an application for a patent by SAAB in 1963 and is given here. s://patents.google.com/patent/US3188 My comments are as follows: The attached patent application (PA) is very interesting but is irrelevant to the topic which I restate: The location of the inlet as shown on the Tejas Mk 2 proposals models is, in terms of development, very trouble prone. It will hold up certification. 2. Before I move on to the topic above I will mention that the PA gives improved pilot visibility as a reason for reducing the inboard sweep- item 16 in the diagram-and shortening the length of the fuselage. Both
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The Tejas costs Prof. Prodyut Das Introduction The Tejas is without doubt the longest running project in Aviation History. Any criticism of the project is countered not by debate but by "flank attacks" the following being typical examples: i) The critic has ulterior motives and likely to be in the pay of the import lobby. Going by the fact that it is ADA's failure that has helped the import lobby- this is rich. ii) The aircraft –an wonder of aviation design “just round the corner” wrt to readiness for production. It has been that way for the last two decades. iii) It is the cheapest programme in the world and ADA has done a marvelous job on such a small budget. American programmes are hugely expensive running into billions. In fact the last has been repeated so loudly and so long that most critics tended to accept that as de facto. Recently I did s
The Tejas Intakes Prof.Prodyut Das Indranil Roy has posted a lengthy thread on the above subject. Since he has directly addressed some of the queries to me I am publishing my initial response below. The weakness of Mr. Roy’s presentation is that he has not explained why an intake buzz occurs nor does the paper mention anything specific but since the source quotes ONERA we must immediately believe that everything is fine. I may be wrong but I got the feeling he did not understand what an intake buzz is . Without that fundamental understanding of why a buzz occurs the danger I have been pointing out in the Tejas intake layout cannot be understood. Below is a common sense understanding of the subject. Intake Buzz: An intake buzz is a highly destructive periodic oscillations caused by the shock wave attaching and detaching from inlet mouth compression surfaces; the shock system moves violently and periodically along the inlet compression surface –which maybe externa
The Fly in the Flow ointment Prof.Prodyut Das Roy has posted on Twitter two pictures to refute my claims that the Tejas canard location is risky. He claims that the above pictures- the upper at twenty five degrees AoA and the lower one at fifteen are “facts” . The pictures- it seemed dodgy to begin with and I was not alone. Mr. Village Hindu have pointed out that the intake flow is not shown and Mr. Prasenjt Das pointed out the lack of Incidence on the canards I thought my following would be of interest to those following the Tejas saga. 1) It seems that the fore plane or canard, is kept at zero or near zero incidence. There appears to be no change in the fore plane angle with a ten degree change in AoA. It is poor design then . Can anyone confirm the fore plane angles? You will also note that the greater vortices shed by the canard in teh upper picture seems entire