JF-17 Thunder Multirole Fighter [Thread 3]

[DaRk WaVe]

What will be the effect of G's after installing a CFT on a JF-17.....and the same applies to the F-16 blk52 that the PAF is getting,how it will effect their performance?keeping PLUS points asides what are the minuses in this case?

with CFTs jet will have reduced maneuverability but still more maneuverable than one with Drop tanks

the advantage of CFT is you will have increased range without any 'considerable' loss in maneuverability

 

[S.U.R.B.]

with CFTs jet will have reduced maneuverability but still more maneuverable than one with Drop tanks

the advantage of CFT is you will have increased range without any 'considerable' loss in maneuverability

Will it be difficult to maneuver with negative G's or with positive ones?

 

[DaRk WaVe]

Will it be difficult to maneuver with negative G's or with positive ones?

Conformal Fuel Tanks for Advanced F-16 Block 50/52/60

Block52/60 F-16 aircraft, currently procured for Israel, Greece and the UAE, have structural, plumbing, and wiring provisions for the Conformal Fuel Tanks (CFT). These external, pod-like fuel reservoirs are attached on the upper surface of the F-16’s fuselage, with the tank’s lower surface conforming to the aircraft shape. The upper surface arrangement allows the CFTs to be relatively light weight because nothing is suspended from them. With an empty weight of 900 pounds, tank set holds 450 gallons (ca. 3,050 pounds, or 2,271 litres) of additional JP-5/8 fuel.

The extra fuel increases range, loiter time, and combat persistence as well as reduces the demand for tanker support. Range increase is on the order of twenty to forty percent, depending on the stores configuration and mission profile. The tanks have neglible effect on the aircraft agility, at subsonic speed, However, at supersonic speed, the drag is increased proportionally to the increase in speed. When fitted with CFT the aircraft retains almost the full handling qualities, flight limits, and signature. A complete set can be removed or replaced within two hours. The CFTs are built to Lockheed Martin's specification, by IAI as a sole source, as part of the Peace Marble V program offsets.

“The CFTs have very little adverse effect on the F-16’s renowned performance,” said Maj. Timothy S. McDonald, U.S. Air Force project pilot for CFT testing at Eglin.“A set of CFTs carries 50 percent more fuel than the centerline external fuel tank, but has only 12 percent of the drag.” The CFTs are designed for the full F-16 flight envelope – up to 9 g’s, maximum angle of attack and sideslip and maximum roll rate.

Israel, for example placed a special significance to the operational flexibility of its new F-16I, derived from the added range and endurance provided by the CFT. For medium range air-to-surface missions, CFTs can eliminate the need for wing tanks. This allows doubling the F-16’s primary weapon capacity and flying with two, rather than one, types of large weapons in a balanced configuration. In long range missions, the use of CFT dramatically increases the operational radius of the aircraft, since it enables the aircraft to fly a long range strike mission, with full weapon's load, and engage in air combat when external (370 Gal) fuel tanks are dropped. When external 370 gal jetissonable tanks or 600gal non-jetissonable external tanks are added the F-16 can demonstrate up to 60-70 percent increase in operational radius. Another Israeli development utilizes a new fuel carrying configuration for the F-16, which enables the carrying of up to four 370 gallon external tanks, plus one 300 gallon under the belly, resulting in 25% increase in mission radius and twice the endurance on patrol missions.

Conformal Fuel Tanks for F-16

 

[S.U.R.B.]

Well it shows that the F-16 will not need to worry much about maneuverability in dogfight which is most of the time at subsonic speed.
In the past(with drop tanks) just like other fighter jets sometimes they had to get rid of their drop tanks to have advantage.......which means loss of range.
& now more or less the same question will the JF-17 get the same advantage with CFT in maneuverability and agility.I think time will tell.
Because as far i know they both have different thrust to weight ratio and air intake.Want some expert opinion on this....thanks.

 

[BATMAN]

u said for blk 2 it doesn't need fuel tanks because of IFR, rite. so tell me one thing, r u planning to refuel the plane in enemy territory?? because with that much payload it will run out of fuel before it could make it back!
even USAF f-16s carry fuel tanks while they're on the mission....
feel free to correct me.

To take off with conformal fuel tanks... more power ful engine is required or some sacrifice on pay load so it is not happening any time soon.
Refueling with probes, will be done before entering enemy territory and i suppose depth of strike will be calculated considering available options and given fuel.
Refueling will be quite usefull even during peace times for example on CAPs time can be increased without landing.

 

[araz]

i can understand the reason why thunders are not getting CFTs in blck II is because pakistan or china both do not have any experiance with CFT installation.

let the Block 52 come and then they will decide how and what to improve to match with Blck 52 and its CFTs.

thanks

Your main problem is the weight of the plane and the engine capacity.With drop tanks, in the fighting zone, you increase maneuverability by dropping them. With CFT you cant do that.Therefore you need a much more powerful engine to cater to the aerodynamic changes required.Please take note of the fact that inspite of having a powerful engine, Bl52s are not as maneuverable as Bl15s.It does point to something. of course there are other factors which account for the increased weight of Bl52s, but in a nutshell this is the reply to your querry. So dont expect CFTs in the JFs anytime soon. However, J10Bs might be another story.
Araz

 

[Peregrine]

Hi,
I was just curious to know that to which extent Pakistan can enhance the capabilities of current block of JF-17 with all the available options including the ones from France or Italy, and how much potent will they make it? Actually what i am trying to know is that; how can prepare JF-17 to utilize it to its full potential with all the best technology at our disposal, and without making any major changes in its design?

 

[razgriz19]

To take off with conformal fuel tanks... more power ful engine is required or some sacrifice on pay load so it is not happening any time soon.
Refueling with probes, will be done before entering enemy territory and i suppose depth of strike will be calculated considering available options and given fuel.
Refueling will be quite usefull even during peace times for example on CAPs time can be increased without landing.

sir i never said CFTs will be fitted on jf...
and yes IFR is very use full, but i was just trying to say that even if the plane have IFR capability it still needs to carry external fuel tanks
just my opinion!

 

[Faadi]

The biggest achievement about JF-17 Thunder is that it involves mostly the technology of Pakistan Air Force and its a giant leap of PAF in self-sustaining its military aviation.

 

[DANGER-ZONE]

found some really good 3D models of Thunder...

 

[DANGER-ZONE]

a few more

 

[Arsalan]

The biggest achievement about JF-17 Thunder is that it involves mostly the technology of Pakistan Air Force and its a giant leap of PAF in self-sustaining its military aviation.

no, what is even more important in JF17 specs if that is is basically a modular design.
it is just like the F16 project. you can see where the F16 have came now starting from its first blocks. the block by block upgrades were massive and the JF17 also have the potential to undertake such massive upgrades without any problem. it means the engine, avionivs, radars... infact almost all of the planes equipment can be replaced by other upgraded euipment if required with out any need of structural modifications.
this can turn out to be a big plus as now the plane is capable to handel any technological breakthroughs through the next couple of decades and can take benefit from those technological advancements.
thus to conclude we can say that if worked on properly, the JF17 will truely be the F16 of future!!


regards!

 

[Cha.Cal]

Hi,

I'm new to this forum. Just came across this video on YouTube and thought of sharing it. Hope it hasn't been posted already.

 

[Tempest II]

Posted by Deino on SDF:

 

[gambit]

Well it shows that the F-16 will not need to worry much about maneuverability in dogfight which is most of the time at subsonic speed.
In the past(with drop tanks) just like other fighter jets sometimes they had to get rid of their drop tanks to have advantage.......which means loss of range.
& now more or less the same question will the JF-17 get the same advantage with CFT in maneuverability and agility.I think time will tell.
Because as far i know they both have different thrust to weight ratio and air intake.Want some expert opinion on this....thanks.

Loss of range? Not necessarily true. It depends on the size of the externals and distance to target.

Fuel management works this way: Engine feed is from fuselage main and as fuel is transferring out of the main, fuel from the wings are transferred inward into the main. If there are external wing tanks, their fuel will feed, or transferred upward, into internal wings. If there is external centerline, its fuel will feed the fuselage main. The goal is centralization of mass and with a liquid mass, we do not want sloshing fuel inside a chamber away from the body's central mass.

EvoMx Fuel Tank Foam

When the fuel sloshes in your tank, the forces of the fuel movement are transferred to the wall of the tank and the force is transferred throughout your vehicle, including your handlebars! Fuel slosh negatively affects your vehicle's handling.

Now imagine this effect in a 3D environment with one wing half filled and the other wing empty with the pilot fighting for his life.

For refueling it is the opposite. Fuel is fed into the fuselage main and the fuel management system will transfer the fuel outward into the wings and the externals, if any.

If the externals must be discarded before their fuel is spent, then distance to target is pointless anyway, the fight is pretty much on your home turf. This is why every mission must be carefully planned. If the mission is home territory defense, then loading the fighter with three or more externals could be excessive. Endurance does not equal to distance. I could circle the airfield for hours and did not really go anywhere.

Cargo type aircraft like airliners and the heavy transports have different fuel management system since fuselage volume space is used for cargo. This is a separate issue.

Externals create other issues such as aerodynamic drag and increase moments of inertia...

Moment of inertia - Wikipedia, the free encyclopedia

Moment of inertia, also called mass moment of inertia, rotational inertia, or the angular mass, (SI units kg·m2) is a measure of an object's resistance to changes in its rotation rate. It is the rotational analog of mass, the inertia of a rigid rotating body with respect to its rotation. The moment of inertia plays much the same role in rotational dynamics as mass does in linear dynamics, determining the relationship between angular momentum and angular velocity, torque and angular acceleration, and several other quantities. The symbol I and sometimes J are usually used to refer to the moment of inertia.

In simpler language, externals' mass makes it more difficult for the aircraft to maneuver, especially in roll axis. The further they are from the fuselage, the greater the difficulty in initiating the maneuver and in stopping the maneuver. Compound this physics issue with aerodynamic drag, remember, this external wing tank is poking its nose from underneath the wing, then in a roll maneuver, we have aerodynamic drag across this mass, not against the tip. So for home territory defense, for example, depending the patrol area, may be only the centerline external is needed, leaving the wings to carry weapons. But if the aircraft cannot carry centerline, then you have no choice but to load up two wing externals. For a standard external, it has been estimated that as much as half of its fuel load is used to overcome aerodynamic drag. The other half actually contribute to the mission. This is why conformals are superior in many ways.