Just to add some basic information about double delta F-7MG wrt ordinary F-7.

A few years back Alan Warnes of AFM published an article and he stated that double deltas tested by PAF showed 35% imporvement in take-off distance, 33% improvement in turn rate at 5000 feet, 50% and 66 % improvements in turn rate at 10000 and 20000 feet, respectively…in fact its turn rate at med to high altitudes was close to that of F-16. In addition, there was at least 25-33% reduction in the safe speed required for low speed loop (likely to be even better at lower altitudes), 50% improvement in spool up time
and 25% improvement in time for acceleration (500Km/h to 1100Km/h) and climb speed. It WP-13F engines produces 14,550 lb of thrust in AB mode, giving it a decent TWR. Finally Grifo 7 on F-7PGs appears to be better than KLJ-6E Lieying in many resects, i.e. range.

The above is inaccurate. As repeatedly mentioned earlier, the PAC Kamra’s website provides contradictory figures for top-speed as well as max. external capacity.

Regardless of the above, it remains that the JF-17 does not have significantly superior specs than the T-50 trainer, which must be a “reaffirmation” for the Tejas. This is because it’s current performance at mach 1.6 and 6 Gs too is achieved at the same empty weight as the JF-17 and T-50.

Thus, Tejas has no performance issues at peak levels of speed and g limits. However, at sea-levels the IAF found insufficient performance, which may be due to the 48 kN F2J3 engine.

It must be remembered that the JF-17 must not be discussed specifically, as it is not the topic of discussion. Off-topic, it may be mentioned that as per Jane’s defence, the JF-17 has FBW in the yaw-axis only, whereas as per PAC Kamra’s webpage, it has FBW in the pitch axis.

Yes.
Some places (even reliable ones) will give u a figure of Mach 1.8 and some 1.6 for JF-17.
Some will give u a take-off run of 400m and some 600m.
Some will give u a figure of +8G and some +8.5G.
Some will tell u in in FBW in pitch axis and some in Yaw axis and some even in both axis.
And so on.

I wont keep going on about things that are no in open, but there are one or two things out in open that I can confirm (sorry but I wont give u sources like Janes/Wiki). Yes, its speed is meant to be Mach 1.8 (was increased from Mach 1.6 following the inlet design change), it G load is +8.5 and it has the FBW in pitch axis…full FBW was not a problem for chinese, but PAF/China decided on pitch axis to start with to quicken the development process and latter batches will include full FBW. Having said this, a fighter’s performance is not measured based on one or things such as empty weight or thrust. For example Yak-130 achieving 41 degrees angle of attack does not mean that LCA/JF-17 and so on are inferior to Yak-130.

Finally, Lets leave it all to a JF-17 thread. I think we all have already said/heard enough about JF-17, T-50, Gripen, their engine, their empty weight and so on. So lets leave them all to their own threads and focus on LCA the topic of this very thread b4 mods again decide to lock this thread.:)

Abhimanyu, Im not sure where those ‘global’ requirements are from. Anyway, the point i was trying to make was rather simple. One cant go round comparing different aircrafts in such manner.:)

As deduced earlier, the current performance of the Tejas is matched by other aircraft of the 6,400 kg class like T-50 and JF-17 thunder, both of which have top speeds of M 1.4-1.6 and 8 G limits. The T-50 is “excusable” as it is a trainer, however, past examples have shewn that as a plane’s weight reaches 6,500 kgs, engines of 48 kN class must be replaced with engines of 54-55 kN class to achieve desired performance.

Hence, the Gripen was installed with the more powerful RM-12 at the very outset. The Tejas too had the 85 kN Kaveri (flat-rated) being developed for it, as envisaged, but due to a 5% lag in intended wet thrust, foreign engines have to be used as an interim. To compensate the lack of flat-rated attribute in foreign engines, the IAF has asked for 90 kN to 100 kN engines.

Similarly, the current JF-17 that is without IFR, and without a finalized European avionics package, too is likely to increase it’s empty weight to >7,000 kgs and will also have to acquire a new engine to maintain performance.

Abhimanyu, since you keep bringing other fighters into your arguments again and again, so lets get a few things straight…but please feel free to correct me where you think Im wrong.

First, the top of speed of JF-17 is projected to be Mach 1.8 and it has a G-limit of +8.5.
Second, JF-17 weighs slightly less than 6,500 unequipped and its RD-93 engine with 18,300 lbs of thrust is considered to be good enough for the purpose. Gripen C weighs around 6,800 kg and its RM-12 with a thrust of 18,100 lbs is also good enough for this machine for its MTOW (whether that is needed or is beyond the point). OTOH, LCA with an empty weight of (lets say) 6,500 kg equipped with F404-GE-F2J3 that produced 18,000+ lbs is not good enough??? May be you should start taking drag into consdieration and not just the thrust.
Finally, trust me they have the engine issue with JF-17 covered just the way Swedes had it with Gripen. We know that JF-17 will have an IFR probe, more pylons and so on which will cause an increase in its empty weight. Its designers know that all these changes will need adjustments elsewhere. CAC will gradually introduce composites to reduce the weight and more powerful engine will also come into the equation at a later stage. But jsut the way it was not an issue with Gripen/RM-12, it won’t be anything like…Oh our fighters weighs too much now, so lets start looking for another engine.

the MTA will employ reverse thrusters and will have very large surfaces that will act as air brakes. also, the MTA will have a lower landing speed as compared to the Tejas, so a distance of 1350m is easily achievable.

on the Tejas, they’ll use brake chutes to cut airspeed as there are no thrust reversers.

just FYI, the landing distances quoted for the C-130 are as low as 660 meters.

See, you learn something new everyday.:) I was under the impression that being a fighter with much higher thrust to weight ratio (i totally ignored the drag and lift surfcaes) LCA Takeoff istance/run should be comparatively lower than MTA. But it seems I was wrong and MTA might be marginally better than LCA in this respect.

No, please explain what you have in mind about that.

Are these figures accurate?

Nothing special under India conditions. Are that over the typical height of 25 m to clear obstacles like high trees?

Sens, have u compared it with the figures for MTA?