PAF Fire Power 2009

[anathema]

I really don't think there is an operational fighter out there with TWR of more than 1 with a full load. Correct me if I am wrong.

Apparently SU 30 mki has TWR greater than one at loaded weight. I am using the word 'apparently' because i am quoting it from wiki which is not a reliable info...

Sukhoi Su-30MKI - Wikipedia, the free encyclopedia

 

[Muradk]

Mirage III and Mirage V have a TWR of below Unity at Loaded Weight. This means that theoretically, sir, this should be impossible for Mirages loaded for battle. When empty, their TWR can be as high as 0.85 with full afterburners, so they can do an almost vertical climb.

As far as I know, the only aircraft in PAF inventory with a TWR of greater than Unity (One) at Loaded weight is the F-16. Second place goes to the JF-17 with 0.95 TWR at Loaded Weight, and third place goes to F-7P. I even calculated the individual TWRs a while back based on information available online.

F-7E TWR at Loaded Weight and Full Afterburners is 0.90. Assuming the F-7PG weighs 10% more than the basic J-7, that TWR goes down.

Mirage III and Mirage V have the same approximate weight and the same engines with the same rated mechanical power output. At loaded weight and full afterburners at sea level, TWR comes out to be below that of the F-7 (I didn't calculate the exact value). Add to the that all the upgrades carried out on our Mirages, which bring a lot of extra weight to carry, and it would be surprising if they could climb vertically when loaded.

JF-17, at loaded weight and full RD-93 theoretical power output is 0.95 TWR. Therefore, the JF-17 must be able to do an almost vertical acceleration better than anything we have except the F-16. Can't wait until March 23rd Fly-By, I guarantee we'll see a pull-up.

F-16 Block 30, loaded weight and full afterburners, TWR comes out to be 1.095. However, during Air Shows and in the pics above, the F-16 is NOT fully loaded, so its weight is NOT its loaded weight. Assuming Empty weight, TWR comes out to be 1.51 with full afterburners. Newer block F-16s require more powerful engines because of all the added weight. An F-16 without high TWR is like a formula one car with an electric engine. It's possible, but what's the point?

Are these calculations wrong?



I have 2000 hours on Mirages and you are telling me it cant be done, Think again ,look at the F-16 it is pulling without any weapons.

AT these speeds you can easily pull a manuv.

 

[Tempest II]

I have 2000 hours on Mirages and you are telling me it cant be done, Think again ,look at the F-16 it is pulling without any weapons.

AT these speeds you can easily pull a manuv.

Thanks Muradk. I think the confussion here might be between a vertical climb and a vertical acceleration. It makes sense that you have said "at these speeds", meaning the plane has to gain speed before it goes into a vertical climb. When is still can be on full AB, it depends on its momentum (speed) to go vertical. It will start loosing speed as soon as it past a certain angle where the combined lift from the wings plus the engine thrust are less than the plane's weight. When it is perfectly vertical there will be no lift from the wings, so you have only thrust pushing the plane up. But then your thrust is less than the weight, therefore, slowly but surely the plane will be loosing speed.

What Muradk is saying about "at these speed", is like a roller skate/boarder" (or even a glider) gaining speed one way or another and the making a vertical maneuver using the momentum.

 

[mean_bird]

yes Mirage can do it beautifully so can F-7

Mirage III and Mirage V have a TWR of below Unity at Loaded Weight. This means that theoretically, sir, this should be impossible for Mirages loaded for battle. When empty, their TWR can be as high as 0.85 with full afterburners, so they can do an almost vertical climb.

As far as I know, the only aircraft in PAF inventory with a TWR of greater than Unity (One) at Loaded weight is the F-16. Second place goes to the JF-17 with 0.95 TWR at Loaded Weight, and third place goes to F-7P. I even calculated the individual TWRs a while back based on information available online.

F-7E TWR at Loaded Weight and Full Afterburners is 0.90. Assuming the F-7PG weighs 10% more than the basic J-7, that TWR goes down.

Mirage III and Mirage V have the same approximate weight and the same engines with the same rated mechanical power output. At loaded weight and full afterburners at sea level, TWR comes out to be below that of the F-7 (I didn't calculate the exact value). Add to the that all the upgrades carried out on our Mirages, which bring a lot of extra weight to carry, and it would be surprising if they could climb vertically when loaded.

JF-17, at loaded weight and full RD-93 theoretical power output is 0.95 TWR. Therefore, the JF-17 must be able to do an almost vertical acceleration better than anything we have except the F-16. Can't wait until March 23rd Fly-By, I guarantee we'll see a pull-up.

F-16 Block 30, loaded weight and full afterburners, TWR comes out to be 1.095. However, during Air Shows and in the pics above, the F-16 is NOT fully loaded, so its weight is NOT its loaded weight. Assuming Empty weight, TWR comes out to be 1.51 with full afterburners. Newer block F-16s require more powerful engines because of all the added weight. An F-16 without high TWR is like a formula one car with an electric engine. It's possible, but what's the point?

Are these calculations wrong?

A little bit--for example JF-17 has a TWR of 0.99 --in the normal way you calculate TWR but ofcourse it always carries 2 wingtip missiels (and if the improved RD-93 is used, even more) but when you are doing these kinds of maneuvers, you do not go with a full tank so figure out a greater TWR. And that applies to all aircrafts.

I am sure Murad sahib will confirm the following-- Aircrafts with lower TWR than unity CAN do vertical pull but they won't sustain it for a long time because TWR<1 means you are decelerating. You can go vertical because your momentum will come in but you will start decelerating. The closer you are to that magic unity number, the slower the deceleration. Planes with TWR>1 can not only pull a vertical climb but actually accelerate while doing the same. Ofcourse there are other factors like friction but lets ignore that for the moment.

Also a 'near vertical' is slightly different from a 'vertical climb' in that if you are inclined, the projection on the X-axis will provide some sort of lift to aid in the climb.

 

[nightrider_saulat]

k_QIYHig0qU[/media] - Mirages Argentinos

a great video for correcting our knowledge

yes Mirage can do it beautifully so can F-7

thnaks for telling me sir yesterday i was thinking that only
4th generation fighter jets can perform this vertical climb-up

 

[PAFAce]

I have 2000 hours on Mirages and you are telling me it cant be done, Think again ,look at the F-16 it is pulling without any weapons.

AT these speeds you can easily pull a manuv.

k_QIYHig0qU[/media] - Mirages Argentinos

I'm not telling you it can't be done. I was asking you. By climb i meant the first maneuver the F-22 pulls in airshows, such as in the video below. The Mirage should not be able to do that, mathematically.

Throw a ball up into the air, it will rise, but it will slow down. That's what I meant by questioning the ability to climb. The F-16 can do that when loaded, but not at MTOW. Mirage III and V will go into climb, then decelerate like a brick thrown up into the air. During 23rd March fly-bys, only F-16s do the vertical pull-up (and JF-17 last time). You never see the A-5, F-7 or Mirages do that.

That was my question, that is all.

 

[Muradk]

I have a photo with me just have to jump into the well to get it for you When I was commanding Mirages I pulled up and went vertical upto 16000ft and leveled out. I was keeping that photo for my website and book but I can make an exception. And we used to do it every day with our students specially the Smartass ones who were eager to get a shot a me
Why do you think I got one of the 3 F-14 during the dog fighting excercise with us I knew TWR of an F-6 vs F-14 in a vertical climb will be crazy so I waited for him in 3 moves he realised oo oo this guy knows his F-6 so he played me went in-front of me and pulled a vertical on me and I went full AB behind him I knew up to 36000ft I can stay with him so I took him out in a vertical climb at 24850ft Clean gun kill. This was the second time I got a kill during an exercise with USN 1 in Karachi 1 in Abu Dhabi.


Another thing the Thrust of JF-17 is wrong.

 

[Muradk]

Basic 1o1 when the airflow stops going over the wings it will stall, You could be at 500knt and still stall a slight mistake of AOA and the air stops flowing over the wings its known as accelerated stall. There are multi factors involved in a AS but this is one of the Major factors.
You don't have these problems in a F-16 FBW the computer takes care of it or bitching betty starts magging in your head constantly.


BACK in the 70s early 80s Mirages and F-6 used to do vertical Climbs on 7th sept, On fighter bases all over 3 to 4 times a day.

If you ever end up in Sargodha go near the base and you can see my F-6 standing there I pulled 7.5g shot Hakimulla, Satar Alvi, Mujeeb. The F-6 was way beyond fixing. Did the same with a Mirage bend its wings during a dog fight but they fixed it later on.

 

[Tempest II]

Another thing the Thrust of JF-17 is wrong.

Thanks Muradk ... ... They need to have you back in the air force and put you in charge of the Public Relationshins department. You do a good job of keeping us "correctly informed" and morivated.

Which thrust numbers are you saying are wrong? These numbers from wiki?

Powerplant: 1× Klimov RD-93 turbofan
Dry thrust: 49.4 kN (11,106 lbf)
Thrust with afterburner: 84.4 kN (18,973 lbf)

 

[hj786]

Another thing the Thrust of JF-17 is wrong.

Thanks Muradk ... ... They need to have you back in the air force and put you in charge of the Public Relationshins department. You do a good job of keeping us "correctly informed" and morivated.
Which thrust numbers are you saying are wrong? These numbers from wiki?

Sorry buddy, I don't think MK sahib will be telling you anything more about the actual thrust/weight of JF-17, he is quite strict about not revealing sensitive info. I think its safe to assume that the stated airframe weight is over-rated and/or the engine thrust is under-rated.

According to MK sahib they have installed a different radar to the one we have been told about, so perhaps they have already replaced RD-93 with an upgraded version also.

 

[Tempest II]

Sorry buddy, I don't think MK sahib will be telling you anything more about the actual thrust/weight of JF-17, he is quite strict about not revealing sensitive info. I think its safe to assume that the stated airframe weight is over-rated and/or the engine thrust is under-rated.

According to MK sahib they have installed a different radar to the one we have been told about, so perhaps they have already replaced RD-93 with an upgraded version also.

True hj786. While I feel there is little chance MK sahib will say much ... ... like a child to a father, I just thought I will let him know my wish list. ... ... He said thrust so I will focus on the engine performance. ... ... I HOPE HE COMES BACK AND TELLS US IT WEIGHS LESS THAN THE NUMBERS ON THE NET TOO!

Anybody got data specifically for the RD-93 and not the generic data for the RD-33? MK sahib had got me onto something here. Janes is saying:

RD-33 Initial production version. Ratings, maximum dry 49.4 kN (11,110 lb st), maximum afterburner 81.41 kN (18,300 lb st).

Initial production was in 1984. This is 24 years later. It makes a lot of sense that we are working with very outdated numbers here. I am not sleeping until I find more rescent info.

 

[TaimiKhan]

Well RD-93 might be in the thrust ranges listed below:

Dry thrust: Around 55.0 or more kN
Thrust with afterburner: Around 88.0 or more kN

RD-93 or WS-13 so called competition is with SNECMA M53 series engines which power the Mirage-2000, so they must be near to or should be superior to SNECMA M53 engine power.

And WS-13 would have to be around 60+kN Dry & 90+kN afterburner thrust, then it will be in a position to compete for JF-17 or its export variants.

And few months back saw an A-5 going vertical & disappearing into the clouds.

 

[Y2A]

really informative, thank you all.

 

[Super Falcon]

where was those 8 JF 17

 

[Y2A]

Great show sir X-men, Really great thank you very much for such wonder full moments, on a lighter node, i never had a chance to capture any thing like this, even though i live 2 kilometers from Karachi Airport ..just kidding....opps it was litile too much lighter may be....