Ok I'm curious, I shared links which I think you didnt even bother to check but are still claiming I'm completely in the wrong. Please share some reading material and tell me why fuel tank cross feed systems to adjust aircraft center of gravity is flawed.
Explaination should not be the usual excuse that Chinese technology is inferior.
That is where you are wrong. I read your links. I understand the info contained within. Now, I will explain why your post is either incomplete, meaning you have inadequate information, or straight out wrong.
Reference...
https://defence.pk/pdf/threads/jf-1...ighter-thread-7.427560/page-314#post-10445120
Here we go...
Even on a commercial aircraft the fuel management system can be used to balance out both wings of an aircraft.
This is true. However, while the apple and the orange are fruits, that is as far as they go in relation to each other. Likewise, while the airliner and the fighter are heavier than air powered vehicles, there are many differences between them, one of them is the fuel storage and management systems that we are talking about at this time.
To start off, this is an airliner...
As we can see, there is not much for fuel storage in an airliner's structure. As much as possible, an airliner's airframe is dedicated for cargo -- money makers -- over other considerations. The result is that fuel storage is...
...Biased in the wings with some in the fuselage.
So while your statement that fuel management is used to 'balance out both wings' are technically correct, it is
INAPPLICABLE to a fighter aircraft. Like how certain things about the apple is inapplicable to the orange.
This is what fuel storage on a jet fighter look like...A high level virtual view...
In a fighter, and I was on the F-111 and F-16, here is how the automatic fuel management system feeds the engine(s):
1- Fuselage tanks feeds the engine(s)
2- Wing tanks feeds the fuselage tanks
3- External understore fuel tanks feeds the wing tanks
As 1-2-3 goes, the fuselage tanks are always full, that means the first tanks to be emptied are the externals, then wings, last are the fuselage.
This is why I asked that ignorant Chinese guy -- posts 4705 and 4707 -- as to which fuel storage and management system is more difficult to design. It is no state secret: the jet fighter.
The airliner's fuel storage and management system is larger and that poses its own unique issues, but in terms of complexities of storage, pumps, fuel flow rate, plumbing diameters, and assorted sundries, the small size of the jet fighter and the demand for maximum internal volume utilization make the smaller jet fighter the greater headache.
So one thing about your comment of fuel storage and management is already wrong.
Next...
Since most modern aircraft are designed unstable, its the job of the FBW to continuously manage the aircraft without pilot input in order to fly it straight.
Yes, that is correct. No issues there.,
Look at the picture below.
That would be this picture...
https://defence.pk/pdf/attachments/thunder-loaded-jpg.469378/
One wing has a C-802 which is ~750KG, on the other wing it is carrying a 800litre fuel tank to balance it out. The aircraft fuel management system and FBW will have to work together.
For the highlighted, where is the technical supporting doc?
If missile not fired the aircraft computer will manage fuel via pumps so that the the opposite wing has similar weight. Once missile fired, the fuel management system will pump out fuel from the wing with the tank and balance rest of the aircraft.
In the absence of supporting technical doc for the previous statement, this following one is flat out wrong.
We -- meaning US military aviation -- have plenty of test data on asymmetric load on any aircraft in our inventory. I will not speak for other air forces, but we can safely assume they have done their tests as well.
There are two main types of asymmetric loads in flight:
- Asymmetric drag
- Asymmetric weight/mass
Each produces different behaviors, especially under maneuvers, on the aircraft.
Asymmetric drag can come from many sources. One source is when an engine is out and the propeller is idle, for example. In this case, we have asymmetric drag and asymmetric thrust.
The wider the spacing of the engines (plural), the greater the asymmetric drag/thrust component. So if one engine on the F-14 is out and one engine on the F-15 is out, the F-14 would experience a higher factor of asymmetric thrust because its engines are spaced wider apart.
Another source of asymmetric drag is 'hung ordnance', as in bombs/missiles that failed to leave the jet on one wing.
Asymmetric weight/mass can come from hung ordnance, but also from
TRAPPED FUEL, such as fuel that failed to transfer from outward to inward.
It is easy to see how the worst type of asymmetric loading is from hung ordnance -- weight/mass and drag.
The flight control system (FLCS) do not compensate for asymmetric load. It is the pilot's responsibility to
MANUALLY trim the aircraft to compensate. In the cockpit with the fuel instrument cluster, there is an indicator of a fuel imbalance condition.
In the older airliner, the flight engineer, who is usually a non-pilot, will
MANUALLY transfer fuel from tank to tank to maintain balance. Today's airliners do not have flight engineers so it falls upon the automatic fuel transfer system or the first officer (co-pilot) to respond to any fuel imbalance condition.
In a jet fighter, even with two pilots, the automatic fuel management system maintains fuel balancing.
You do not want the FLCS to automatically countering the effects of a fuel imbalance because the behaviors of a maneuver and an asymmetric load are very similar. The FLCS, even the most advanced today, can mistake an asymmetric load with a pilot command. In essence, you are asking the flight control computer (FLCC) to second guess the aircrew.
I learned to fly when I was in high school, before I got my driver's license. I knew how to take off and land an aircraft before I learned how to parallel park a car. I took my girlfriend on airplane rides but we rode the bus to restaurants and movies. In the air, if I put right foot to rudder pedal, I would be creating an asymmetric drag, no different than flying with a hung bomb. So by the time I joined the USAF, it was clear we do not want the jet to guess what the cockpit is doing and countermanding what the pilot want. If there is an asymmetric load from whatever source, we want the aircrew to manually compensate for that because they are supposed to be aware of what is happening.
If missile not fired the aircraft computer will manage fuel via pumps so that the the opposite wing has similar weight. Once missile fired, the fuel management system will pump out fuel from the wing with the tank and balance rest of the aircraft.
I would like to see supporting technical doc for the J-17 on that. Or on any fighter for that matter.
Once a jet released a weapon, there is an
INSTANTANEOUS loss of weight/mass and drag. Internal fuel transfer are not that fast, unless we are talking about 'Chinese physics'?
If the J-17's fuel storage and management system is conceptually the same as the F-16, and I am confident they are the same, then by the time the bomb/missile is released over a target, most likely all J-17's externals and wing tanks are empty. That means once the bomb/missile is released, the J-17 as pictured above will be flying with an asymmetric drag condition with nothing to balance it out, except pilot's wheel trim input. So where are the supporting sources for your assertion?
My suggestion for you is this...
You are treading into a highly technical area that no computer game has all the information. Do your research -- a lot of it -- before you post.