Let us go to the extreme for now...
Airliners are large enough aircrafts to use in this discussion.
In the examples above, we can see on both the Boeing and the Lockheed where their engines are. The voltage spikes and the darker areas are the clues.
On the Boeing, the three engines are close enough together in the tail section that they are indistinguishable from each other. All three engines formed a cluster. Not so for the Lockheed, we can see the engines as represented by the large and dark areas on the wings.
From this extreme example, we can move the scale back to the aircrafts in discussion: MKI and JF-17. If we install a missile-like object on the airliner, most likely this object will disappear among the spikes. Simply put, even though the missile is an RCS contributor, its signal will literally be 'absorbed' by other signals. We can even be generous and say that destructive interference will cancel out the missile's RCS. On the other hand, constructive interference will make the overall RCS greater. We simply
DO NOT KNOW. Precisely because we do not know that 'stealth' designs internalized their weapons. We do not want to take chances that constructive interference will occur. Best to go with the worst case scenario that constructive interference will always occur, so carry the weapons internally.
Missiles and bombs from all manufacturers will have similar dimensions and shapes based upon their yield designs. You can make a 250lb yield bomb the size of a train if you want, but why? So if we are to take the standard weapons load on the MKI and the JF-17, we will see that those bombs and missiles are pretty much similar in dimensions. They are already the same in shape, right?
Now we have to ask: Which is physically larger in terms of structural dimensions, the MKI or the JF-17?
Which aircraft is so large that bombs and missiles could electronically be 'absorbed' by other structures? We can be confident that a cluster of bombs/missiles will not be distinguishable on the airliner. But here we are talking about two aircrafts - MKI and JF-17 -- that have similar structural dimensions and structural array.
Dimension is wing tip to wing tip, for an example. Simple.
Array is more complex. It means wing shape and location on fuselage. Change the shape and there will be a different RCS. Put the wing higher on the fuselage and there will be a different aircraft RCS. Put the wing forward/aft on the fuselage and there will be a different aircraft RCS as well.
We know that the weapons locations are not significant variables on both aircrafts. Where else can we put them? So in terms of RCS, we know
WHERE they will be: Wing tips, below the wings, and lower fuselage.
So does this mean that since the MKI already have a higher RCS due to being physically larger than the JF-17, a fully loaded MKI will have an even higher RCS value? Yes, we can be confident in that assumption.
However, and keep in mind that bombs and missiles are pretty much the same all over, weapons load on the smaller JF-17 may -- not definitive -- be more electronically distinguishable, like the engines on the Lockheed, thereby rendering the JF-17's smaller size irrelevant.
Radar detection algorithms will call a large cluster as a 'target', but if there is a cluster of smaller clusters, that will be classified as a 'target' as well. A fully loaded JF-17 may very well fall under this.
From my experience, given the
CLOSING SPEED, the difference in sizes, fully weapons loaded or not, between the MKI and JF-17 is meaningless. the radar will process and see both at the same time and at the same distance.