JF-17 Thunder Multirole Fighter [Thread 7]

[Dr. Abdul Basit]

Some nice clicks by a friend of mine

 

[khanasifm]

No dual seater news in 2016 ?????

 

[razgriz19]

JAS 39 has the excessive oil exhaust above the aux power unit and jf has below so with wind spots on the body, never seen on F16

Pretty sure JF-17 leaks oil, most likely upon shut down. And PAF mechanics don't bother cleaning it up afterwards.
I used to clean the belly of CFM-56 engine(B737), that thing also leaks oil when shutting down. Actually most, if not all turbines leak oil when they shut down because the bearings are sealed by air, and as soon as the engine shuts down there is no more air so some of the oil falls down inside the engine and that's why they have these drains on the bottom. Obviously some engines leak more than others.

 

[SQ8]

Pretty sure JF-17 leaks oil, most likely upon shut down. And PAF mechanics don't bother cleaning it up afterwards.
I used to clean the belly of CFM-56 engine(B737), that thing also leaks oil when shutting down. Actually most, if not all turbines leak oil when they shut down because the bearings are sealed by air, and as soon as the engine shuts down there is no more air so some of the oil falls down inside the engine and that's why they have these drains on the bottom. Obviously some engines leak more than others.

A more detailed reason for it

"A aircraft's jet engine oil system must compensate for varying altitudes/pressures acting on it. It must be vented to outside air, and have a regulation system within it to maintain the proper pressure in the system. This is most often called the "Breather"

There are three critical things in each bearing compartment or oiled area within the engine. Oil pressure flow, oil sump/return and a 'vent'. The vent is responsible for letting the compartments 'breath' to the outside through a valve. Without proper breathing (venting), the oil would blow through the rotating seals and be lost. (Early jet engines used a 'total-loss' oil system that would consume gallons of oil per flight; see YB-49 crash history)

So in summary, jet engine oil systems must be vented to the outside atmosphere to allow proper pressurization and operation of the seals within the system. The vent will allow oil smoke and vapor to escape; even though there is an air/oil separator in most systems. This is visible along the bottom of the engine as 'leakage' and smoke. In some cases over filling or extreme maneuvers can cause oil to 'blow overboard' through the breather system.

There are also 'shaft seals' that have drain lines that are grouped together at openings on the bottom of the aircraft for proper overboard drainage. These seals constantly rotate at high speed where accessories are mounted to the engine gearbox, and would naturally loose a small bit of oil. Since you can't stop the leak, you control it by passing it out of the aircraft. Typically this 'leakage' was defined by technical limits. Example; "PTO shaft seal leakage limits - not to exceed 10 drops per minute of operation"

Another thing to consider as 'leakage' is routine maintenance on the engine while it is installed in the air-frame. If you have to replace an oil component, or remove an oil line for access to another component, the spilled oil will accumulate within the aircraft's panels, ribs and spars. Even though you may try to remove all the spilled oil, some will remain. As the engine runs and heats the area, the now highly fluid hot oil will find it's way to the nearest rivet, drain hole, or panel."

Thanks TEG for that^

 

[Naif al Hilali]

 

[Naif al Hilali]

Isn't that an F-5, not a JF-17. If you look closely you can see two engines, were as the JF-17 only has one.

The underside profile also matches the Tiger, not Thunder.

Sorry, this was in reply to @Oscar; we were talking about oil venting and I thought a recent photo of the F-22 (not yet on Google BTW) with the same would be apropos here.

Yes, and the third aircraft is a T-38. Photo is from the article discussed in

https://defence.pk/threads/f-22-evolving-tactics.468529/

I thought you were going to leave us play by ourselves come December 25; I guess still up cooking or digesting the Christmas Eve ham (not turkey I know).

 

[messiach]

Internal oil leakage is minimized by air-pressurizing the bearing sump areas with bled off from the compressor. Airflow into the sump minimizes oil leakage across the seals in reverse. That's the idea.

A more detailed reason for it

"A aircraft's jet engine oil system must compensate for varying altitudes/pressures acting on it. It must be vented to outside air, and have a regulation system within it to maintain the proper pressure in the system. This is most often called the "Breather"

There are three critical things in each bearing compartment or oiled area within the engine. Oil pressure flow, oil sump/return and a 'vent'. The vent is responsible for letting the compartments 'breath' to the outside through a valve. Without proper breathing (venting), the oil would blow through the rotating seals and be lost. (Early jet engines used a 'total-loss' oil system that would consume gallons of oil per flight; see YB-49 crash history)

So in summary, jet engine oil systems must be vented to the outside atmosphere to allow proper pressurization and operation of the seals within the system. The vent will allow oil smoke and vapor to escape; even though there is an air/oil separator in most systems. This is visible along the bottom of the engine as 'leakage' and smoke. In some cases over filling or extreme maneuvers can cause oil to 'blow overboard' through the breather system.

There are also 'shaft seals' that have drain lines that are grouped together at openings on the bottom of the aircraft for proper overboard drainage. These seals constantly rotate at high speed where accessories are mounted to the engine gearbox, and would naturally loose a small bit of oil. Since you can't stop the leak, you control it by passing it out of the aircraft. Typically this 'leakage' was defined by technical limits. Example; "PTO shaft seal leakage limits - not to exceed 10 drops per minute of operation"

Another thing to consider as 'leakage' is routine maintenance on the engine while it is installed in the air-frame. If you have to replace an oil component, or remove an oil line for access to another component, the spilled oil will accumulate within the aircraft's panels, ribs and spars. Even though you may try to remove all the spilled oil, some will remain. As the engine runs and heats the area, the now highly fluid hot oil will find it's way to the nearest rivet, drain hole, or panel."

Thanks TEG for that^

 

[Zarvan]

In a recent program Habib Akram suggests recent visit of Nawaz Shareef to central asian countries and other small countries is mainly because he is trying to sell JF-17 thunder to them. Does any one has any other information on this ???
@Oscar @Windjammer @Horus

 

[graphican]

In a recent program Habib Akram suggests recent visit of Nawaz Shareef to central asian countries and other small countries is mainly because he is trying to sell JF-17 thunder to them. Does any one has any other information on this ???
@Oscar @Windjammer @Horus

Habib Akram is stupid and visibly biased germolist. He often keeps blood pressure of Haroom ul Raheed high because of his stupid analysis and unrealistic extracts.

How do you sell a hardware to anybody? Has Pakistan bought anything in the past from China, Russia or a like? The norm suggests experts are invited or sent to producing country where they look at the product, learn about its specs, prices are looked at and when everything is finalized, leadership meets to decide lateral aspects, like influences, conditions and what the buyer/seller should do and what not. This is where PMs get involved.

Is Nawaz a salesperson of Kamra? What are his expertise in selling military hardware? Is he a leaders in himself? Is he even an influencer? MF keeps a written paper with him when he meets world leaders.. would he go and influence other countries to buy military hardware from the military he hates within his country?

 

[Zarvan]

Habib Akram is stupid and visibly biased germolist. He often keeps blood pressure of Haroom ul Raheed high because of his stupid analysis and unrealistic extracts.

How do you sell a hardware to anybody? Has Pakistan bought anything in the past from China, Russia or a like? The norm suggests experts are invited or sent to producing country where they look at the product, learn about its specs, prices are looked at and when everything is finalized, leadership meets to decide lateral aspects, like influences, conditions and what the buyer/seller should do and what not. This is where PMs get involved.

Is Nawaz a salesperson of Kamra? What are his expertise in selling military hardware? Is he a leaders in himself? Is he even an influencer? MF keeps a written paper with him when he meets world leaders.. would he go and influence other countries to buy military hardware from the military he hates within his country?

Selling product doesn't he starts describing its features. It means that he talks about selling JF-17 on senior level basically asks there politican leadership to consider JF-17 also in there future procurement.

 

[graphican]

Selling product doesn't he starts describing its features. It means that he talks about selling JF-17 on senior level basically asks there politican leadership to consider JF-17 also in there future procurement.

If you are talking about Nawaz is taking initiative then even then this doesn't hold true. Initiatives too have their channels. Could PM Nawaz had not sent Pakistan's defence minister or representatives of POF, HIT or Kamra first? Were these representatives accompanying Nawaz on these trips? Ask these questions and you'd know the answer.

 

[araz]

If you are talking about Nawaz is taking initiative then even then this doesn't hold true. Initiatives too have their channels. Could PM Nawaz had not sent Pakistan's defence minister or representatives of POF, HIT or Kamra first? Were these representatives accompanying Nawaz on these trips? Ask these questions and you'd know the answer.

I remember when the MMRCA contract was being negotiated and trials going on Cameron went to India to drum up support for the Typhoon.
I dont know what the fuss is about. If the JFT makes sales and profits the whole country will benefit out of it and Nawaz Shareef represents the country.
So he is doing the right thing and this should be appreciated.
A

 

[I FLY HIGH]

I remember when the MMRCA contract was being negotiated and trials going on Cameron went to India to drum up support for the Typhoon.
I dont know what the fuss is about. If the JFT makes sales and profits the whole country will benefit out of it and Nawaz Shareef represents the country.
So he is doing the right thing and this should be appreciated.
A

There is no cure of Nawaz phobia to the psuedo intellectual class of Pakistan . The are always busy to downgrade their PM on intl forums.

 

[Cool_Soldier]

No dual seater news in 2016 ?????

It seems project is delayed for some time.
Hope to see in first Quarter of 2017.

 

[graphican]

I remember when the MMRCA contract was being negotiated and trials going on Cameron went to India to drum up support for the Typhoon.
I dont know what the fuss is about. If the JFT makes sales and profits the whole country will benefit out of it and Nawaz Shareef represents the country.
So he is doing the right thing and this should be appreciated.
A

@araz;

You've missed the topic. Who wouldn't appreciate Nawaz if he was making an effort to sell something. We are not discussing if Nawaz should be appreciated for his effort, rather question is "is nawaz doing an effort"; and answer is no he is not.

Nawaz has spent almost 4 months of his tenure in UK in various trips. Would you conclude he was there to make sale of JF-17s as well? I hope not.