Details of heat exchangers brazed

17 numbers of heat exchangers were to be brazed, some of aluminium and some of stainless steel.
The minimum core weight of the aluminium heat exchanger(Liquid-Air HE) was o.28 Kg and the finished weight of the same heat exchanger was 0.85 Kg.
The maximum core weight of the aluminium heat exchanger(Secondary HE) was 8.78 Kg the finished weight was 12.0 Kg.
The aluminium fins are as thin as 0,0762 mm.

There were a number of stainless steel heat exchangers.
The minimum core weight of the heat exchanger(Precooler) was 8.8 Kg and the finished weight was 12.0 Kg.
The maximum core weight(Primary HE} was 15.6 Kg and the maximum finished weight was 23.0 Kg.
The fin thickness was 0.0762 mm.
If you look at the thickness of the fins the difficulty in brazing can be gauged. CLOSE CONTROL OF THE BRAZING TEMPERATURE WAS ESSENTIAL FOR THE SUCCESS OF THE BRAZING OF THESE HEAT EXCHANGERS.
All these heat exchangers are performing successfully in the Supersonic air craft developed by Aeronautical Development Agency ,LCA TEJAS, and have clocked hundreds of flight hours. India is one of the few countries which have such a sophisticated technology.
My association with this project was in the initial brazing trials as I left BHPV in 1995. Credit should go to R&D team led by Mr. Panigrahi DGM(R&D) who completed the project. Recently ADA has placed an order worth Rs.20 crores for a few sets of these heat exchangers.