So, me and readers need to ask you why you think Cone has more items exposed to radar view than DSI?
Why dont you dare to answer?
I bet you dont know again. Thats why never throw claim that you cannot defend
Simple...The cone have more surface area. The ramp have edges and angles. I said this before. So what make you think I am 'afraid' to answer?
The DSI 'bump' is at best half a cone, so it has less surface area than the cone. How much more simple can it get?
Now...If you want to get into which is the better to hide the fan blades, it is the cone, not the DSI 'bump'.
Here is why...And people will see how I put this issue to rest...For good...
The engine's contributorship to RCS is more than just the fan blades...Much more...
In the above example, we see how a helicopter's rotating blades produces recognizable radar flash patterns. Not only do blade flashes are in recognizable patterns, but because a blade is not symmetrical in construction due to aerodynamics reasons, which will present variations in surface exposure to the radar which affects reflection amplitudes, the amplitude variations of the flashes will also be in a recognizable pattern. Odd number of blades will produce higher flash frequencies because each blade make two flashes per revolution.
Helo rotors EM analyses is called 'radar detection of agitated metals' (RADAM)...
Analysis of radar detection of agitated metals (RADAM)
It has been observed that the radar returns from moving multielement metal targets often exhibit an unexpected modulation that has both random (or noise-like) and semicoherent components.
To accomplish any of these, the effect must be well understood, and we have therefore undertaken a program of research to study the radar detection of agitated metals (RADAM).
This mean we can tell which pattern came from an even bladed rotor or from an odd bladed rotor, which hint at what model and eventually the helo's origin country.
RADAM analyses are already deployed...
MSTAR - Wikipedia, the free encyclopedia
Man-portable Surveillance and Target Acquisition Radar (MSTAR) is a light weight all-weather battlefield radar Doppler radar operating in the J band. It is usually used by Artillery Observers to acquire and engage targets in bad visibility or at night. It is capable of detecting, recognizing and tracking helicopters, slow moving fixed-wing aircraft, tracked and wheeled vehicles and troops, as well as observing and adjusting the fall of shot.
All of the highlighted have one thing in common: That each object have something on it that is repetitious, predictable in motion, and is metallic, hence the words 'agitated metals' in 'radar detection of agitated metals' (RADAM).
Amazing, ain't it? Is your supposedly aviation 'background' or 'study' helping you understanding this sh1t?
Anyway...No different than when the radar is looking face on at a jet engine's fan blades. In fact, looking face on at a jet engine's fan blades will produces far more blade flashes and recognizable patterns than looking edge on as in the helo's rotors.
In the above example, the top illustration is a simplified visual representation of the multiple stages of a jet engine.
The second illustration is a civilian type jet engine. The third illustration is a military jet engine. See the size differences and location of those differences?
The general construction and working theory of the jet engine works this way: The fan assemblies are connected to a common shaft. Each fan assembly represent a compression stage. There are different blade count per compression stage. Not only blade counts are different but blade sizes are usually different as well from one compression stage to the next successive stage. The diameters of the fan assemblies is progressively smaller into the engine. The distances between stages get shorter into the engine.
The process is called 'jet engine modulations' (JEM) detection for target recognition, tracking, and (hopefully) identification.
Radar MASINT - Wikipedia, the free encyclopedia
One open-literature study combined several pieces of radar information: cross-section, range, and Doppler measurements.[20] A 1997 Defense Department report mentions "Air Force and Navy combat identification efforts focus on noncooperative target recognition technologies, including inverse synthetic aperture radar imaging, jet engine modulation (JEM), and unintentional modulation on pulse-based specific emitters".
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1606562&tag=1
In this paper, the modulating mechanism of radar echo, namely jet engine modulation effect, caused by the rotating-blades, is analyzed by equivalent the engine intake as a wave-guide model in this paper. And a changing law of target RCS and modulation spectrum is studied.
PIER Online - A Novel Hybrid Aipo-MoM Technique for Jet Engine Modulation Analysis
A NOVEL HYBRID AIPO-MOM TECHNIQUE FOR JET ENGINE MODULATION ANALYSIS
A novel hybrid adaptive iterative physical optics-method of moments (AIPO-MoM) technique is presented for the electromagnetic analysis of jet engine structures that are both electrically large and complex in both stationary and dynamic cases. In this technique, the AIPO method is used to analyze the smooth inlet region, and the MoM method is used to analyze the electrically complex compressor region, including blades and a hub. It is efficient and accurate by virtue of combining the respective merits of both methods. In the dynamic case, a concept for modified impedance equation is proposed to reduce computational load. Numerical results are presented and verified through comparison with Mode-FDTD and measured and commercial simulation packages results.
RADAM is sufficient for helicopter rotor signature analyses but not for complex structures like a multistage turbine engine.
For the civilian jet engine, its mission requirement have its fan assemblies very large compared to the military engine with the humans to provide scale. Not only are the civilian engine have large fan assemblies but they are more concentrated towards the front end of the engine itself. Thrust from the civilian engine comes from the combination of fan and compressed exhaust. Thrust from the military engine comes mostly from the compressed exhaust. That is the 'bypass air' difference.
As the radar signal impact the first fan blade assembly, a recognizable pattern is produced. As portions of the transmission is diffracted and travels through the engine to successive stages, each stage produces its own recognizable pattern. The closer the fan assemblies are together, like how the civilian engine is, the greater the interactions between multiple reflections and this equals to a higher RCS contributorship. Then if the seeking radar is sophisticated enough in data processing, a very unique and complex engine signature will be produced. We can store this knowledge and disseminate it later for everyone, or the immediate radar can use it to enhance tracking. However, it is accepted that beyond stage 3 or 4, and given the fact that this is inside a highly dynamic target, the EM interactions are too mathematically complex to model and predict.
JEM analyses is much more difficult -- not impossible -- with the military engine. For the military engine, each fan stage is smaller in diameter than the civilian engine, giving the radar less surface area to reflect. The stages themselves are further apart from each other so diffracted signals will impact the stages in less consistent directions. Civilian jet engines often are podded and therefore have very short intake lengths, whereas military jet engines in the fighter class are usually fuselage enclosed and have very long intake lengths similar to a waveguide and if there are any deviations from straight, the radar signal may be weakened from multiple reflections before meeting the first fan blade stage. This short versus long intake length difference necessitate a near true frontal radar view of the engine face on the fighter aircraft for any significant radar encounter. Because the civilian jet engine is so much larger in fan stage diameter and have very short intake lengths, there is a greater range of freqs (wavelengths) available to create the JEM effect, even down to the single digit ghz freq, whereas for the military jet engine, its physical construction and layout in the aircraft does not guaranteed that the JEM effect is consistent enough for tracking, let alone identification, for any freq.
This is why the criticism against the PAK for its intake system is only
PARTIALLY valid. Its engines are too deep inside the fuselage, requiring a near true frontal radar view. It is only because of JEM analyses that the PAK would have a vulnerability in that event.
Any radar can process EM reflections from the engine's first fan stage, but only radars specifically designed for specific military purposes may -- not will -- have JEM analysis capability.
So how do we deny the seeking radar the JEM effect on our fighter jet engine? Certainly not by putting a little DSI zit or boil or bump in front of the engine face.
Either make the intake system serpentine or put the engine face behind a cone.
The serpentine intake system like on the F-22 and F-35 is obvious enough in its ability to weakened a radar signal thru multiple reflections.
For the cone, its position in front of the engine face is sort of a 'mini serpentine' intake system by forcing the radar signal, especially high freq (short wavelength), to become surface wave (SW) on the cone's surface. Diffracted signals on the cone's backside edges will be weakened before they meet the engine face. Any backscatter from the engine face will meet the cone's backside, resulting in even more multiple reflections. So while as a structure, the cone does present a greater amount of surface area to the seeking radar then the DSI zit/boil/bump, its ability to protect the engine face from the seeking radar far outweighs its negative in comparison to the DSI setup.
I do not expect you to understand even 1/10th of what I presented above. You are too much of a dumbass, too stubborn and too technically illiterate. I do not expect the Chinese crowd here concede that they are wrong in the belief that the DSI zit/boil/bump was intentional for RCS control. They are too blinded by nationalism to admit to any amount of intellectual honesty, even when confronted with irrefutable proofs.
For the truly objective minded readers, any time any of the Chinese boys starts spouting off about DSI zit/boil/bump being for RCS controls, feel free to use the above arguments to debunk such nonsense. Or just point the fool to this post and watch him sputter.