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Depicted above is the effect of bank angle on a stealth aircraft while turning. A broader bottom of a stealth aircraft also creates flat plate like reflections on a radar screen while turning depending on the bank angle. A broader bottom will give more reflections and detection range will increase. AMCA is nearly 2m broad at its bottom compared to 90 cms of LSA. The combination of thin bottom with 45* fuselage sides will ensure that LSA fuselage bottom and the wing-fuselage combination do not become corner reflectors. AMCA with 20* side angles will add to these reflections. No aircraft in the world has 100% stealth based on just shaping. We need a combination of shaping, small size, active RF cancellation and absorbent materials. Small size & internal weapons bays offer much higher level of stealth. In nature all Predators are small in size, have outstanding agility, ability to hunt at night, merge with surroundings due to their camouflage and have extremely strong jaws with pointed teeth. So, any interceptor aircraft must follow these rules to be able to fight, kill and survive. I kept these very principles in mind while designing LSA.
Depicted above is the effect of fuselage side angle on the detection range of a stealth fighter. These depictions are based on F-35 JSF of USAF. LSA has better stealth compared to AMCA. A Flying wing does not have such fuselage side angle and are considered the best shapes for stealth. AMCA has this side angle as just about 20* compared to 45* for LSA and therefore AMCA will be detected from longer distances at any height it flies compared to LSA. Once and aircraft is within the range where the fuselage sides create flat plate reflections, going closer to the radar will multiply these reflections as the fuselage and wing start acting as corner reflector and concentrate the radar reflections towards the radar. As a result AMCA will have to fly longer routes to its target to zig-zag thru enemy defences which will reduce its penetration range in enemy territory while LSA will be able to fly more direct routes to the target and hit deeper in enemy territory. AMCA will have to stay at least 18 Nautical miles away from all long range and medium range radars and SAMs while flying at 36K feet to avoid detection while this range reduces to just 8 nautical miles for LSA due to its side fuselage angle of 45*. This shorter detection range for LSA will make it better suited for SEAD/DEAD operations compared to AMCA.
AMCA has undergone wind tunnel testing but its engine of choice is not available. LSA has undergone very limited CFD analysis and its bulkhead designs are also ready with engine of choice readily available. So how you compare the two? Which is closer for prototype development-LSA or AMCA?
Shown below are the bulkhead designs for LSA. I have hidden the bulkhead design for weapon bays as that will give out the most outstanding feature of this design. But we are ready to go if MOD gives us clearance.
I asked DRDO for the coordinates of HF-24 air foil. They kept quite. I needed an air foil to generate data thru CFD analysis. Instead ruing my luck, I went ahead and designed my own 5% t/c, 0.5% camber and 35% maximum point of thickness air foil based on research published by NASA about supercritical air foils. And what I designed is shown below. This air foil at zero alpha and Mach-1 has shortest transonic regime as the shock waves of top surface and bottom surface are positioned at the rear most tip. This is the type of air foil an aircraft capable of super cruise needs. I have managed to shrink the transonic regime from 0.8-1.2Mach to just about 0.9-1Mach. This means that LSA will not need reheat to go thru sound barrier due to its very short transonic regime.
Shown below are the 12 alpha Mach-1 contours of the same air foil. Any aerodynamics engineer who sees these will go mad for the outstanding quality of this air foil.
Shock cones.
As for fuel
