The Raven
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You are showing a systematic use of specious reasoning, that is based on deriving assertions that suit your purposes from arguments that have no relevance to the claims made. You come across as narcissistic, who doesn't just have a wish to prove himself, but a fetish to achieve intellectual superiority over others and derive comfort by insulting them. I have now seen this behavior from you over multiple threads. In detail:
You need to provide proof of the following assertions you have made earlier:
1. There is an EW system installed on the tail of Block 3.
2. This EW system needs air cooling.
3. This cooling is provided through the opening seen on the base of the tail in Block 3.
So far, you have provided no such proof. The website you have linked is not a proof of anything. What is written on that website is only an opinion that is not backed by any official or credible sources.
I am not 'hung up' on anything. You are losing the plot here. Let us revisit my assertions:
I - The block 3 has undergone substantial upgrades which makes it infeasible to upgrade Block 1 and 2 to be exactly equivalent to Block 3.
II - An example of these upgrades is the installation of a fibre optic data bus.
III - This new data bus gives Block 3 capabilities that cannot be replicated easily in Block 1 and 2, an example being increased resistance to EMP attacks.
Now, you have made the following incorrect assertions regarding changes to FBW and data bus:
1. Free up internal space for the AESA - The AESA components are at the nose of the aircraft, whereas the physical connections of FBW databus run through the main body. This is completely irrelevant.
2. Improve mission computer performance - The interface between the silicon based mission computer and the fibre optic based data bus is a known point of bottleneck. The databus has nothing to do with the mission computer. What you are probably trying to say is the changes provide higher data rates.
Then there is the utterly amateurish assertion that since PAF can rewire the Mirage, it can replace copper wiring in Block 1 and 2 with fibre optics. First of all, let's be very clear - by spending enough money anything can be done. We need to look at what it takes to change copper wiring into fibre optic wiring.
Fibre optic is a very sensitive material that is prone to damage by a range of environmental factors such as temperature, vibrations, and humidity. This necessitates special cladding which changes the dimensions of the wiring when compared to copper. Throughout the length and breadth of the aircraft, space is allocated at design time in a very precise manner taking into account the dimensions of the wiring. This changes the entire internal mass distribution within the aircraft. This is what @araz referred to whom you rebuked with impertinence. There is a reason why Block 3 took years to finalize. It has undergone internal changes that take years to design, test and validate. Changing Block 1 and Block 2 to this configuration is not simply a matter of stripping out some wires and replacing them with new wires.
First of all, let's do some approximate calculations. Let us approximate the opening on the base of the Block 3 tail by a circle which is 7 inches in diameter. This gives it a surface area of 0.087 sq ft (approx.) The diameter of RD-93 is 3.41 ft (using online calculator to convert mm to ft)
http://www.uecrus.com/eng/products/military_aviation/rd93/
which leads to a radius of 1.7 ft. Of this, let us discard 0.7 ft for the engine shaft and housing. Of this, let us assume an arc of 3 pi / 4 radians is actually exposed to incoming air on each side. This annular region has an area of (3 pi / 8) * ((1.7)^2 - 1) = 2.23 sq ft on each side of the engine. From the above link, the RD-93 has a bypass ratio of .49. If x is the surface area of the by pass air intake, and y is the surface area to the opening of the compressor, then x/y = 0.49 and x + y = 4.45, which gives y = 3 sq ft (approx) and x = 1.45 sq ft (approx). Note that I am probably over-simplifying a very complex engine geometry here. By this computation, the inlet at the base of tail comprises approx 6% of the by pass intake. At supersonic speeds, due to pressure variance, the air intake from the small opening can go up to 12% of the entire by-pass air flow. Does this seem like a small opening to you? Your amateurish brain cannot comprehend the apples to oranges nature of the comparison you are drawing with the Kfir.
I merely said if someone wants to install an AESA radar, the Mirage has the internal volume. I did not specify which type of AESA (air cooled vs liquid cooled).
You need to justify why such an overhaul or MLU would make Block 1 and 2 exactly equivalent to Block 3. None of what you have written above is being disputed. Why are you going off on a tangential rant? And finally, your janes.com link is not even working. Did you copy/paste it from another website without checking?
Mate, you post this diatribe and you call me narcissistic?! All I have said is that there are no technical reasons why Block I and II aircraft can't be upgraded to Block III specification. This is in line with what the PAF itself has envisioned from the whole JF-17 programme, and the future trajectory of the fleet. And as I have repeatedly stated in my prior posts, this depends on funding, much like anything else. Not once have I ever said that it is for definite. Aside from anything else, if you want to dispute the technical feasibility, it should be clear to anyone with half a brain that 50 Block III aircraft equipped with AESA from an operational point of view won't be enough to face the burgeoning fleet of AESA equipped fighters in the IAF inventory. If the SABR or equivalent becomes available to the PAF for its Vipers, it may not feel the need to upgrade earlier Block I/II aircraft to Block III standard. All this is in line with PAF's historical approach to upgrading its assets, it's not anything new.
I'll state it as bluntly as I can - I completely disagree with you. If the PAF can resurrect nearly destroyed SAAB 2000 Erieye aircraft, install the Erieye radar and associated avionics and sensors, if they can keep over 50 year old Mirages still operational and relevant, if they can embark on a fifth gen fighter development programme, then they shouldn't have any technical difficulties in upgrading Block I and II aircraft to Block III specification. I agree to disagree with you.
Just to highlight a few points on which you may not be aware. The fairing at the top of the fin on the JF-17 houses EW equipment. This has been around since Block I. The MAWS have been upgraded from UV based detectors to infrared sensors, which work better when they are actively cooled. The same infrared MAWS on the J-10C which appear to be cooled by the same intake that's on the J-10C which has now been added to the Block III with the same EW suite. Or maybe that's just a coincidence to you, or the designers of the Block III were just lazy and ported over the same intake on the J-10C to cool the RD-93 (not used on the J-10C) without bothering to see whether it provides the same ram air cooling dynamics for the AL-31/WS-10 as it does for the RD-93. You can't just copy and paste an air intake for two completely different engines with different thermodynamic, thrust, weight, size and air flow characteristics.
There is an excellent paper which describes the advantages of current gen infrared based MAWS vs previous generation UV based MAWS if you want to understand why that's important.
https://www.researchgate.net/publication/241361323_Two-color_infrared_missile_warning_sensors
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