Combat Aircraft technology and Evolution

[ersakthivel]

Well before arguing about ranges of various fighters,

people should use the same criteria for all fighters like,

their range on full combat load at full internal fuel only, at the same altitude

there is no point in adding drop tank fuels in basic range calculations.

because the efficiency of a fighter will become known when only they are compared against common yardstick,

There is no point in saying that I have a chines hand book that lists the defined in china military standard range of X and Y at A and B configuration while we are comparing other fighters on the condition of full weapon load with internal fuel only configuration.

If a range was not given for full combat loads at internal fuels only for a certain altitude there is no point in taking it a measure of efficiency of a fighter. Because simply there is no purpose in knowing how long your fighter flies empty with internal fuels only without knowing how long it will fly for sea level altitude with full weapon load on internal fuels only config.

There is no way in the world for the ,"only for export - not used by PLAF fighter like JF-17" to beat the ranges of experienced fighter makers who have churned out thousands of fighters that fly all over the globe, even more suspect when chinese have no engines of their own for all metal JF-17 which weighs around 6 tons.

It is to be expected that that the JF-17 which has a far lesser wing surface area than the Tejas to weigh considerably less than the tejas. the fact it does not means it can hold no edge over any other fighter in range. since it has no optimized engine for it either. And it was inducted into PAF with no IOC or FOC trials by PAF , also gives no clarity on it's full weapon load -internal fuels only combat range.

Also the new canard or cranked or compound deltas employ vortice generation to maximize the lift to drag ratio as has been explained on the F-16 XL design and are well suited for the high sub sonic cruise speed.

So simply saying that the due to delta design the Tejas has high sub sonic drag and , since clinging on to basic chinese range figures without giving the figures for full combat load , internal fuel only range will only confuse the matter further,

people complain after watching Tejas for a decade different figures are bandied out in different sources,

Then why can't they give a B]combat range on full combat load at full internal fuel only, at a particular altitude[/B] for the "well proven export only fighter" called JF-17?

Leaving aside the glorious LCA ,surely the chinese makers should have tested JF-17's combat range with full weapon load in internal fuel only condition before exporting them. Because without this buyer can not measure the effectiveness of the fighter and whether it will suit it's operational needs.

If they did what are the figures?

and 3000Km is the ferry range with the max external tanks. the FC-1's long range ability is a proved one and the design and test flight team claimed that this little bird has longer ferry range than another product from the same team with the Delta wing--J10

If this is true then the same can be argued in the case for tejas Vs Mirage-2000 or tejas vs F-16 can it be?

 

[Defcon 1]

1.obviously so called' KM/L' or 'L/KM'(car driver?) is your own invented 'method of calculation'.I just follw you logic for fun...you chose or invented such funny method as some one said....

Just shut up. First you claimed Tejas has subsonic drag which was debunked. Then you stuck to high basic range which was shown to very high compared to other fighters by @p2prada. Then you stuck to ferry range which was again shown to be higher for the amount of fuel it carries. Now you have no arguments so you are saying that km/L is useless and ferry range of 3000 km should be accepted unilaterally.

in mig 29's case,that was powered by two RD33...LOL

So??? how does that gives you the right to multiply the km/L ratio by 2? Can mig 29 fly with one engine? At the end of the day, it flies with both engines and its ferry range is calculated using both engines only.

you needn't teach me how to get 'basic range' ...basic range is our concept and defined in china military standard, tested and evaluated in the Real flight tests not a model computing data... I'm afraid you'd better find the internal fuel range data of different airplanes for some estimated comparation...

No one is trying to teach you that. All people are saying that both ferry range and basic range of JF17 are very high in comparison to the amount of fuel it carries.

F16C blocks 30/40/50 's 2450 Mile should be from the F-16.net...4220km from the wiki...and so called 8000-8400L was a range which varies according the sources.

That is not the point, the point is that you changed your own claim in order to win argument which shows dishonesty.

No one is trying to do any precision calculations anyways.

 

[ersakthivel]

the following statement says more about the inefficient high empty weight low thrust to weight ratio nature of J-10 then the record beating cruise ability of JF-17!!!!!!!

Since every one knows j-10 is hugely under powered due to its vey high empty weight,

and 3000Km is the ferry range with the max external tanks. the FC-1's long range ability is a proved one and the design and test flight team claimed that this little bird has longer ferry range than another product from the same team with the Delta wing--J10

If this is true then the same can be argued in the case for tejas Vs Mirage-2000 or tejas vs F-16 can it be?

especially the following statement is a complete bunch of lies,

you are ignoring the disadvantage of tailless delta wing during the subsonic flight: the low Lift/drag ratio and not so good subsonic cruise ability , and the feature of LCA's aerodynamic layout: thick and short which brings more drages...

Then if we use the F-16 vs F-16 XL analogy-------- using the same "discredited disadvantage of tailless delta wing during the subsonic flight: the low Lift/drag ratio and not so good subsonic cruise ability" -----------how come the F-16 XL managed to beat the plain F-16 for range weapon load and close combat specs?

you'd better think about another right example : the F16's ferry range..F16 is another typical low internal Fuel weight ratio design

F16C/D's Maximum ferry range 2450 miles with maximum external fuel.
F16A/B's Maximum range 2400 miles

The answer according to its own designers is by using cranked arrow design on F-16 XL which due to vortice generation effect gives a highly beneficial lift to drag ratio for F-16 Xl over plain F-16s .

Because tejas is also using the same cranked arrow tail less delta config of F-16 Xl . So the statement --"discredited disadvantage of tailless delta wing during the subsonic flight: the low Lift/drag ratio and not so good subsonic cruise ability" is a stupid lie spread typically by ignorant people unwilling to concede there are no obvious disadvantage in tejas's cranked arrow tail less delta design

if the statement -----"discredited disadvantage of tailless delta wing during the subsonic flight: the low Lift/drag ratio and not so good subsonic cruise ability" is true then why was the same design used on J-10 and J-20?

Are chinese experts that dumb that they don't know this basic "aerodynamic fact"!!!!!

If people say canards will cure all those drag problems , then they have no right to question the tejas's cranked arrow tail less delta design , because job of canards, LREX , LEVCON, cranked arrow and compound arrow are one and the same, i.e generate lift inducing vortices which help in maximizing the lift to drag ratio .

That is why most of the modern fighter designs like J-20, PAKFA ,Grippen, TYPHOON, RAFALE,Tejas are all going for either one of the concepts in the list above.

If people have any material to the contrary they can give source here. Surely there is nothing top secret about such material.

If the radar detection range posted in the link below is true then,

http://www.jf-17.com/2012/08/10/jf-17-radar-detection-ranges-for-f-16-and-f-22/

JF-17 is simply a turkey shoot target for tejas, because even with 2 long range BVRs the RCS of tejas will be less than half of the similar configuration tejas .

So while tejas mk-1 can detect and track the JF-17 from 120 Km range , the pilot of the JF-17 won't even see the tejas on his screen before the Akash mk-1 or mk-2 BVR fired from it is up in front of his nose!!!!!!!

 

[ersakthivel]

POST: EDIT

in post 123 ,

"JF-17 is simply a turkey shoot target for tejas, because even with 2 long range BVRs the RCS of tejas will be less than half of the similar configuration F-16" .

 

[ersakthivel]

fotografersha: Почему я люблю плохую погоду

you can clearly see the vortex formation of both the LREX and Canards on su-35 which has no canards and Su-30 which has canards in these photos from the web site.

In the same way cranked arrow also generates vortex to assist lift .

They are all for the same purpose whether they move or not.

 

[p2prada]

1.obviously so called' KM/L' or 'L/KM'(car driver?) is your own invented 'method of calculation'.I just follw you logic for fun...you chose or invented such funny method as some one said....and in mig 29's case,that was powered by two RD33...LOL

Actually, this measure is used. When F-16A reaches bingo they calculate at 3 Kg/mile.

Americans use pounds/mile. So that's 7 pounds/mile at bingo.

4. F16C blocks 30/40/50 's 2450 Mile should be from the F-16.net...4220km from the wiki...and so called 8000-8400L was a range which varies according the sources...actually we often see such data for ferry range config: 1050 + 2*370+300 gallon=7911L and another saying--around 14000lb fuel in total=8200L...once again ,I do suggest doing some simple estimate with a range...sometimes this way might be much better than so called precision calculation. as a fan or enthusiast, I don't think we have such abilities.

I have been checking out some F-16 figures.

F-16A, the aircraft carries 3.1 tons of fuel internally and 3 tons externally. That gives it a ferry range of 3900 Km.
F-16A is supposed to give 1900 Km on internal fuel alone. The aircraft has demonstrated 1000NM on internal fuel.

You can say that RD-93 is more fuel efficient than F-100, but the F-16 is still carrying 1000L more fuel to get that 1800 Km range. That 1000L advantage gives the F-16 an extra hour of flight time in this profile.

Do you have JF-17's per hour fuel consumption? F-16 should burn about 700 Kg every hour in such a profile, mach 0.9, 30000-35000 feet. JF-17 will have to burn at less than 500Kg/hour to offset the difference between the two and get the same range. This is considering JF-17 has taken 1000 Kg of fuel just to taxi, hold, take off and reach altitude with 400 Kg in reserve while F-16 has burned 1200 Kg for the same.

While I take back some of what I said earlier, about JF-17 having a considerably lesser range, LCA also, I still don't believe it has a 1800 Km range.

 

[shiphone]

that's it.... 1900km for F16A's internal fuel range...quite close to our normally quoted F16's data in Chinese books and papers...
and the comparable F16C equivalent(simliar empty weight and take-off weight, same class of engine): the J10 with around 3.1-3.3 ton's internal fuel has a around 1800 km basic range(some paper calimed that there was around 200Kg unuseable fuel in pipes)...the trainer---J10S could achieve 1650km basic range due to more drags of the two seater config...

-------------------
maybe I can make it simple here:

RD-33:
Maximum thrust: 50.0 kN (11,230 lbf) Dry, 81.3 kN (18,285 lbf) Afterburning.
Specific fuel consumption: 75 kg/(kN·h) (0.77 lb/(lbf·h)) dry, 188 kg/(kN·h) (1.85 lb/(lbf·h))wet

F100-PW-229: (not the early model F100-PW-100 on F16A)
Maximum thrust: 17,800 lbf (79.1 kN) military thrust, 29,160 lbf (129.6 kN) with afterburner
Military thrust: 0.81 lb/(lbf·h) (82.6 kg/(kN·h)) ,Full afterburner: 1.74 lb/(lbf·h) (177.5 kg/(kN·h)

basicly I would say some basic ratio(per hour) : 0.575-0.6 : 1...so JF17's 1800km with 2.3 tons of fuel VS F16A's 1900km with 3.1 tons of fuel ----it's still possible although my not so rigorous calculation...

the estimated condition for the Basic range test is : 11000m altitude and 0.85M cruise speed...the reserve fuel request normally is for 10-15(30 mins for twin engine planes) mins flight time ...

------------------
I would like to list another two chinese planes' fact sheets from the <China Aircraft handbook> published by PLA GAD(General Armament Department) here----the late 70s' J8(I) project and 60's J7(I)...these two were powered by the Turbo Jet engine which has higher fuel consumption rate.

the J7(I):
1838kg internal fuel--- range:1200 km

the twin engined J8(I)
4.05 tons internal fuel --- range 1580KM(11000km,0.85M--note: not full inernal fuel and without any drop tanks)

 

[shiphone]

the chief designer of JF17 project --YangWei had a a course of lectures at the China's top science and engineering university: Qinghua university in Mar 2006...in this lecture , he talking about the FC-1's PT04 which was going to take the maiden flight later and mentioned the range data: 1800KM and 3000KM for the first time...

as he said , actually PAF emphasize the range request( top priority) for this 9 tons class fighter..the team made a lot of effort to achieve this goal. some other performance was sacrificed

新枭龙战机座舱现代化程度高，三平一下，可实现双手操作，枭龙战机应客户 要求（巴基斯坦），最强调的是航程，航程达1800km,转场航程3000km，对于九吨级的战机是非常难得的；

---------------
BTW,ADA old website used to claim the LCA's internal fuel endurance--around 30-40 minnuts...and your saying --around 45 minuts is not very reasonable to me...I have questioned the old 40 minutes claim for quite a while...but I didn't find too much discussion on BR forum and here.

 

[p2prada]

BTW,ADA old website used to claim the LCA's internal fuel endurance--around 30-40 minnuts...and your saying --around 45 minuts is not very reasonable to me...I have questioned the old 40 minutes claim for quite a while...but I didn't find too much discussion on BR forum and here.

In an operational environment both Gripen and LCA do 40 mins at low altitudes. The flight profiles are not clear. At higher altitudes, SFC should considerably improve for both and give one hour on internal.

Don't forget that this considers supersonic flight time and combat persistence also. So you can say the aircraft could end up doing 2 or 3 minutes supersonic flight. For eg: Both aircraft may have to do Mach 1.2 up to 50NM with 3 minutes of combat.

That's why even F-16C has a max combat radius of 430 Km while carrying 2x1000 Kg LGBs with internal fuel. That's effectively 30-45 minutes of flight time at different combinations of speed and altitude.

F-35 vs. F-16 Range - The Ghastly Truth

Actually, F-16C with 2x2200L tanks+ 2x1700L CFT + 2 Aim-120 + 2 Aim-9 + 2 GBU-10 has a combat radius of 1150 Km in Hi-Lo-Lo-Hi profile. This is with 50NM dash to and away from target. This matches Mirage-2000's capability with 8 Mk-82s + 2x2000L tanks at 640NM. So, that 4200 Km figure of the F-16C has literally been halved in combat situations. That's why ferry range is useless. So, that's 8 minutes of flying at mach 1.2 at low altitude followed by 1800 Km at mach 0.9 at high altitude. Gives it roughly just above two hours of flight time. A shadow of its former 4+ hours endurance on such fuel loads. LCA, Gripen and even JF-17 obviously don't have such a configuration let alone carry 7800L of external fuel. So that two hour flight time for F-16 should be considerably lesser on the other three, say half the endurance with half the combat radius.

This link gives 230 Kg/min consumption for Mirage-2000 during combat missions. So this should finish up 700 Kg in 3 minutes at supersonic speeds.
Flight data

 

[shiphone]

...in counting of J7's H-H-H interception profie case , we often set a Scene of 2 minutes air combat with after burner...but anyway most times the plane takes the flight at subsonic and high subsonic speed.and during internal fuel and ferry range flight test the plane don't use the afterburner.even during the taking off period.

...Ferry range is still a important parameter of a airplane and listed on the performace table of every fighters...I don't think it is useless .the data of internal fuel range and ferry range are associated and reflect some essential aerodynamic characteristics of each plane's design...

------------------------------
as I said ,what I did in the original LCA thread were:

1. correct the FC-1/JF17 internal Fuel weight ratio.
2. clarify the so called JF17's "a phenomenal claimed range of 3000 km"---it's a ferry range data, and it's official and possible.
3. also give a concept in China Military Standard of Airplane design ---airplane's Basic range. ...JF17 is designed under China's standard and evaluation system, different country has different concept and standard
shiphone ↑

...once again ,I have no big divergence with you on the so called 'combat radius' datas...it's quite complicated to discuss in consideration of so many conditions. ..

Actually, F-16C with 2x2200L tanks+ 2x1700L CFT + 2 Aim-120 + 2 Aim-9 + 2 GBU-10 has a combat radius of 1150 Km in Hi-Lo-Lo-Hi profile

BTW 2200L tanks(600 gal) is a none drop tank ,normally for ferry flight or for limited A-G use in much safer scene.

...the M2k the data sheet on that site might be overrated...LOL
------------------------------------
-----------------------------------
to some member......LOL

Just shut up. First you claimed Tejas has subsonic drag which was debunked. Then you stuck to high basic range which was shown to very high compared to other fighters by @p2prada. Then you stuck to ferry range which was again shown to be higher for the amount of fuel it carries. Now you have no arguments so you are saying that km/L is useless and ferry range of 3000 km should be accepted unilaterally.

shut up? and 'Debunked'?....LOL....easy ...little friend
it seems that you need to read my early and orignal statement first.

you are ignoring the disadvantage of tailless delta wing during the subsonic flight: the low Lift/drag ratio and not so good subsonic cruise ability , and the feature of LCA's aerodynamic layout: thick and short which brings more drages...
shiphone ↑

obviously I have two meanings:
1. the disadvantage of tailless delta wing during the subsonic flight: the low Lift/drag ratio and not so good subsonic cruise ability
2. the feature of LCA's aerodynamic layout: thick and short which brings more drages

the first is the common disadvantage of delta (tailess delta) wing design. although it has some other advantage in High subsonic ,transonic and supersonic speed range. note the difference between high subsonic and subsonic speed, you might need go back to Lca thread to read the Q&A between Mr,Deckland and Truespirit started from #1616...and I was talking about the Lift/drag ratio mainly...
the second is LCA seems a little bit fat(thick diameter and short length) even compare with other delta wing planes ..F35 is also accused for its 'fatness' and drag issues.

 

[ersakthivel]

F-16A, the aircraft carries 3.1 tons of fuel internally and 3 tons externally. That gives it a ferry range of 3900 Km.
Tejas carries 2458 kg internal fuel and 3125 liter external fuel and has a ferry range of 3000 Km according to wiki specs despite being little thicker than other deltas it still has the same ferry range as that of thin JF-17 .So the cranked delta assisted better lift to drag ratio is in play here.

so a 25 percentage difference and that still we don't know whether tejas ferry range is as per international norms or under hot indian climate.

So the argument that a small fighter like tejas can not have normal combat range and ferry range goes out of the window along with following bunch of "chinese aerodynamic truths " , quoted below of course.

. the disadvantage of tailless delta wing during the subsonic flight: the low Lift/drag ratio and not so good subsonic cruise ability
2. the feature of LCA's aerodynamic layout: thick and short which brings more drages

thicker diameter was due to the larger radar demand from IAF which can be used to swat Fc-1 or JF-17s like house flies in south asian skies with longer range BVR missiles . SO it is not a simple plain oversight.

In this department LCA scores over planes like grippen and comes neck to neck with planes like RAFALE .

And the vortex lift from the cranked delta of tejas ,

which cancels all the so called delta drags from grand mother story days

won't be erased from few people's mind ,

even if I dump pages upon pages of F-16 XL vs F-16 analogy in this thread,

So no point in wasting more time on these useless ,"chinese aeronautic truths" which apply only in the land of the dragon, listed in quote below,

he first is the common disadvantage of delta (tailess delta) wing design. although it has some other advantage in High subsonic ,transonic and supersonic speed range. note the difference between high subsonic and subsonic speed, you might need go back to Lca thread to read the Q&A between Mr,Deckland and Truespirit started from #1616...and I was talking about the Lift/drag ratio mainly...

the second is LCA seems a little bit fat(thick diameter and short length) even compare with other delta wing planes ..F35 is also accused for its 'fatness' and drag issues.

.

So we can safely say that the combat range and ferry range are dependent upon fuel fraction as I said before and close shop on this topic perhaps.

typing three LOLs in a post won't make any body a genius. Accepting the truth of F-16 Xl vs F-16 analogy is a good start for learning process!!!!

You can see F-16 Vs F-16 XL range comparison for the advantages of cranked deltas over plain deltas for ranges.

A tail less delta has more drag than the JF-17 type conventional lay out fighters like JF-17. But the cranked delta has much better LIFT for their drag. SO they have a preferable LIFT to DRAG ratio over JF-17 type conventional lay out fighters like JF-17 is explained beautifully in the following link.

http://www.airforcemag.com/MagazineArchive/Pages/1983/November 1983/1183f16xl.aspx



Tejas is also a cranked arrow tail less delta like F-16 XL.

In the photo below a normal F-16 flies along side the F-16 Xl.

tejas

If physics laws have no nationality What holds good for F-16 Xl over plain F-16 should also hold good for tejas and generally for all other tail less deltas universally on the atmosphere of the earth.


Please give any proof with credible source for ,"the disadvantage of tailless delta wing during the subsonic flight".

Even the fuselage plug recommended by CEMILAC for reducing drag by better adhering to smooth and gradual increase cross section from5 to 6 meters for tejas applies only in ,"super sonic flight" and it has no implication for subsonic loiter time.

There is no chinese physics or indian ignorance attached to ,"the disadvantage of tailless delta wing during the subsonic flight"

Then how come another tail less delta Mirage-2000 has such phenomenal range?



If these Fuel fractions are true then ranges then according to universal physics laws ,

with optimum weapon load the combat range will also strictly follow the same ratios for normally combat useful mission is generally accepted practice.

No matter which manufacturer lists what range for their fighters with full external load of fuels and full weapon load for their fighters ,

with optimum weapon load the combat range will also strictly follow the same Fuel Fraction ratios for normally combat useful mission

 

[ersakthivel]

the chief designer of JF17 project --YangWei had a a course of lectures at the China's top science and engineering university: Qinghua university in Mar 2006...in this lecture , he talking about the FC-1's PT04 which was going to take the maiden flight later and mentioned the range data: 1800KM and 3000KM for the first time...

as he said , actually PAF emphasize the range request( top priority) for this 9 tons class fighter..the team made a lot of effort to achieve this goal. some other performance was sacrificed

---------------
BTW,ADA old website used to claim the LCA's internal fuel endurance--around 30-40 minnuts...and your saying --around 45 minuts is not very reasonable to me...I have questioned the old 40 minutes claim for quite a while...but I didn't find too much discussion on BR forum and here.

In BR I have seen a page which clearly states that tejas will have comparable range to Mirage-2000 despite being smaller due to fuel fraction and higher use of composites considerably reducing its empty weight , despite having much larger proportional wing area exposed to drag.

 

[Defcon 1]

Actually, this measure is used. When F-16A reaches bingo they calculate at 3 Kg/mile.

Americans use pounds/mile. So that's 7 pounds/mile at bingo.

This is while calculating ferry range? i.e. flying at optimal altitude at optimal speed?
Also, Bingo is low fuel right?

 

[p2prada]

...Ferry range is still a important parameter of a airplane and listed on the performace table of every fighters...I don't think it is useless

It is useless because it has no combat value. That was my meaning of useless.

I mean, do you fill up your car tank and then drive at the most optimal speeds in your city along with the most optimal gear change at the most optimal RPM values in the most optimum weather conditions. You obviously don't. Practically impossible in real world conditions, don't you think? There will always be a car in front of you that will unbalance your optimal conditions.

as I said ,what I did in the original LCA thread were:

Of course, your data for JF-17 seems right.

BTW 2200L tanks(600 gal) is a none drop tank ,normally for ferry flight or for limited A-G use in much safer scene.

Yeah, the 600 gal tanks are not drop tanks. In the config I posted, the aircraft will land with the tanks. It will not engage in WVR combat. Escort aircraft will or it will run away.

...the M2k the data sheet on that site might be overrated...LOL

This is official from Dassault. It actually matches the F-16 in some range performance figures and is known to consume lesser fuel than F-16.

 

[p2prada]

This is while calculating ferry range? i.e. flying at optimal altitude at optimal speed?

Yes.

Also, Bingo is low fuel right?

Bingo is the point where the aircraft has enough fuel to go back to base and land, with reserve fuel for emergencies.

 

[ersakthivel]

If fighters have similar Ferry range then what will be the difference in combat range with optimal design weapon load at the same flight altitude and same flying condition between them?

Nothing much I suppose.

Because ferry range indicates the aerodynamic efficiency of a fighter at a fixed config compared to same for other fighters at the same config.

So for optimum design weapon load at the same flight profile with internal fuel only , there won't be much difference between them in combat range either.it will be in accordance with Fuel Fraction percentage of fighters.

An crap like tail less delta will have higher sub sonic drag and tejas is bit thicker goes out of the window because tejas is a cranked delta like F-16 XL not a plain old delta like Mirage-2000.


So if F-16 Xl the cranked delta has substantial combat range advantage over a plain cropped delta F-16 , the same can be true for Tejas as well compared to JF-17 and Mirage-2000.

F-16 XL(cranked tail less delta like Tejas) exceeds F-16-A in all parameters so it will hold good for tejas over JF-17(both JF-17 and F-16 A are cropped deltas with tail) (FC-1)and Mirage-2000

 

[ersakthivel]

We all learn. No one knows everything. : )



I agree. Like I said, that was just simplifying a complex answer. Indeed, delta-canards and cranked deltas solves this issue because you dont have to increase your Angel of attack too much to turn more, which inturn means you save energy. However it has a draw back. Canards and crank-Deltas creates massive drag in the high supersonic flight regimes. The reason why these planes don't reach the speed of a MiG-29, Su-27 or a F-15{2.3, 2.3 and 2.5 respectively}. The reason why the Su-30MKI has a poor max-speed of only 1.9. Bad for scramble missions and Intercept missions where speed is crucial. They don't even reach a single engined F-16s speed of Mach 2.1. Lets see if levcons are the solution to this problem. Too early to tell although the signs are they are the solution.

Su-30s are generically low wing loading planes, not high{although compared to the Su-27 they are high wing loaded because of their increased empty weight, but they fall in the low wing loading category.}. They just have a poor thrust to weight ratio compared to the MiG-29, the reason why their STR is poorer than the fulcrums.


They wont come deep where their logistics wont be able to sustain them. But they can still occupy a significant amount of our land to humiliate us.


Exactly. Su-30 has fuel pumps from Russia{or does it? I think HAL has got more ToT on the Su-30s than they did with the MiG-21s, so probably they are manufactured in-house} while MiG-21 got their fuel pumps from non-Russian ex-soviet states. Russia just stopped their production.

Yup. Just replace IAF with HAL. They indeed are incompetant to even reverse engineer a fuel pump. Even now we buy critical spares which HAL cannot manufacture from other non-russian ex-soviet states.

Losing stability is an exaggeration. The Center of Gravity changes on Low fuel and the pilot has to compensate for that. This is subject to several aircraft, not just the MiG-21. Since MiG-21 is generally a unforgiving plane, this means the pilot now has to be extra cautious and compensate for that too. Losing stability means MiG-21 is dangerous to fly when its fuel is 2/3rds, which is rubbish. Most of the MiG-21s will crash that way because I suspect most landing are with less than 2/3rds fuel anyway.

In tonnage, and range yea, the Tejas has an advantage. We are talking about a plane of more than 60 years ago. If Tejas cant even do that then the engineers working on the Tejas should be shot. What's troublesome is, the MiG-21 a plane which first flew in the 1950's still beats Tejas in Thrust to weight ratio, Angle of Attack{forgot to mention it earlier}, climb rate, G tolerance and Max Speed. Ideally it shouldn't be superior in these parameters{if not all atleast a few}, but it is superior, which is a shame on us.

MiG-21 Bison's Kopyo-M has a range of 80km for 5m2 Target. Not 50kms. LCA doesnt even have a fully integrated radar as of now. It just flew with it. The integration is still ongoing. Ofcourse it as no guns, and no short range missiles{slaved to its radar} and never fired a long range missile as of today.


MiG-21Bis
Empty Weight + full fuel = 5460 + 2364 = 7824kgs
R-25-300 - 7100KGF After Burner, 9900KGF Emergency Thurst

Tejas
Empty Weight + full fuel = 6560 + 2458 = 9018Kgs
F404-GE-IN20 - 8665kgf After Burner, 9165kgf Emergency Thrust

Thrust to weight with full fuel and afterburner

7100/7824 = 0.91 MiG
8665/9018 = 0.96 LCA

Just a 0.05 difference which is negligible in practical terms.

With *Emergency thrust kicking in, this is where it gets interesting -
9900/7824 = 1.27 MiG
9165/9018 = 1.02 LCA

Too lazy to add missile weight. But I increased the fuel weight to full instead of calculating with half.


*Emergency Thrust is a little known thrust. I prefer to call it a Superburner. But unlike an Afterburner, it cannot be used continuously for longer periods. It's like nitro for cars. Good to give the needed boost for a couple of minutes then shut it off. MiG-21 has a massive "nitro boost" or a "superburner" for scramble missions to climb up faster to meet its opponent, and ofcourse even for dogfights.

Some known Emergency Thrusts.
Fighter - Afterburner - Emergency {all in kgf}
MiG-29K - 9000 - 10500
MiG-29UPG - 8300 - 8700
Su-30MKI - 12500 - 12700

That's the thrust of each engine BTW. MiG-29K uses that to take-off from its ramp. So the massive difference.

FGFA which and f-22 both of which are some sort of cranked or compound deltas that have the highest top speeds at present.

So no drags for compound deltas. The crank or Levcons or LREX create flow energizing vortex based air flows on the upper surface of deltas giving them high lift to drag ratio that nullifies all the dis advantages of old plain deltas.

I am surprised to find that for intercept missions Mig-29 flies at top speeds all the time. truth is if a MIG-29 flies at its top speeds of Mach 2 plus it will empty its fuel in a few minutes and fall out of the sky before reching interception point. Other than F-22 which flies at cruise speed of mach 1.6 no other fighter is designed to fly at its top sped for 100s of kms.

Mirage-2000 has higher top speeds but RAFALE has lower top speeds despite having higher TWR.Both are deltas.Mirage-2000 has far better top speed than RAFALE despite both being deltas

Why?

Not due to drags on deltas planes are designed that way.

Straight line higher top speeds are irrelevant nowadays as they can never be used to out run a missile or in close combat or reaching a point in sky faster.

So fighters are nowadays designed with lower top speeds and higher agility in close combat thats all.

In the hot skies of Goa Tejas reached the sea level top speed of 1350 Km per hour (during a powerless dive from 4 Km in flutter test) which is the same as Mig-29 and Su-30 MKI in indian conditions. So no drag issues for deltas when it comes to top speeds. In fact the opposite is true .look at the CONCORDE.

deltas are always most efficient in super sonic flight regime .

Most of todays 4th grn fighters have 3 sq meter RCS in air to air interception mode and 5 sq meter for 80 Km range of Mig-21 does not apply here.

we don't know that whether any nitro boost is there in GE-404 IN 20 . but this nitro boost will run out so short on MIG-21 and all its fules will be depleted in no time .


If you add missile weight this nitro boost is nothing.

No one has to shoot tejas designers!!!!!!!!

at mk-1 it is equal to grippen C/D

and mk-2 it is equal to Grippen NG and has a bigger radar almost equal to RAFALE!!111

Why shoot the poor guys who accepted every single change proposed by IAF for the past two decades.

 

[Defcon 1]

Yes.



Bingo is the point where the aircraft has enough fuel to go back to base and land, with reserve fuel for emergencies.

3 kg/mile gives around 0.43km/L which lower than average rates of 0.47 or 0.50 km/L as calculated above. 3lb/mile gives even a lower number. How can fuel efficiency be lesser at Bingo than the average for the whole flight? Shouldn't fuel efficiency increase as the aircraft loses fuel and becomes lighter?

 

[p2prada]

3 kg/mile gives around 0.43km/L which lower than average rates of 0.47 or 0.50 km/L as calculated above.

As I mentioned before while giving the calculations, I did not take into account fuel consumed for taxi, hold, take-off and climb. I did it on the assumption that the aircraft is already in the air and has full fuel, so all the aircraft are equal at that point. Those are not real figures, it was only meant as a comparison.

Fuel consumption changes drastically based on the conditions. It's not like cars, but I was using that analogy while comparing. That's why the figures.

 

[ersakthivel]

I wouldn't go as far to say LCA has better lift to drag ratio, since we don't know that, but yup, LCA does have a lower wing loading which means it can have a good climb rate. But you are forgetting to include another parameter which is the Thrust to Weight ratio.

A MiG-21Bis is a very very unique aircraft. It has extreme acceleration in emergency thrust mode, which is employed during scramble, interception missions, and also dogfights, but within a time limit. It basically shoots up like a rocket to be ready to face the enemy at a respectable altitude. With such extreme acceleration, Thrust to Weight ratio gains more importance than wing loading.

Further reading material....


Modern times

Perhaps the most dramatic WEP feature was found in the MiG-21bis fighter jet. This late variant of the standard Soviet light fighter plane was built as a stopgap measure to counter the newer and more powerful American F-16 and F/A-18 fighters until the next-generation MiG-29 could be introduced to service.

The MiG-21bis received the upgraded Tumanski R-25 engine, which retained the standard 42 / 65 kN normal and forsazh power settings of earlier R-13 powerplants, but added a new super-afterburning system. Use of this "diamond regime" provided a massive 97.4 kN of thrust for no more than 3 minutes in actual wartime use. Use of this temporary power gave the MiG-21bis slightly better than 1:1 thrust-to-weight ratio and a climbing rate of 254 meters/second, equalling the F-16's nominal capabilities in close-quarters dogfight.

In air combat practice with the MiG-21bis, use of WEP thrust was limited to 1 minute, to spare on the engines' 800 flight hours lifetime, since every second of super-afterburner use counted as several minutes of regular power run due to extreme thermal stress. When WEP was on, the MiG-21bis's R-25 engine produced a huge 5 meter long blowtorch exhaust - the six or seven brightly glowing rhomboid "shock diamonds" visible inside the flames gave the emergency-power setting its "diamond regime" name.

War emergency power

The MiG-21 has a delta wing. The sweep angle on the leading edge is 57°.The angle of incidence is 0° while the dihedral angle is −2°.

The Tejas is single-engined multirole fighter which features a tailless, compound delta planform and is designed with "relaxed static stability" for enhanced manoeuvrability

, This is the basic truth about Mig-21(tejas is also a delta with sweep back angle of ). But all the while you are arguing deltas have more drag!!!!!!!!!


The specs of Mig-21 bisons,

Empty weight: 5,339 kg (11,770 lb)
Gross weight: 8,725 kg (19,235 lb)
Powerplant: 1 × Tumanskiy R25-300, 40.21 kN (9,040 lbf) thrust dry, 69.62 kN (15,650 lbf) with afterburner each.

The specs of Tejas,

Empty weight: 6,500 kg (14,300 lb)
Loaded weight: 9,500 kg (20,944 lb)
Max. takeoff weight: 13,300 kg (29,100 lb)
Powerplant: 1 × F404-GE-IN20 turbofan
Dry thrust: 53.9 kN[93] (12,100 lbf)
Thrust with afterburner: 85 kN[94][95][96] (19,000 lbf)

For a gross weight of 8725 Kg Mig-21 bison has a thrust of 69 tons a TWR of 0.79 ,

For a gross weight of 9.5 tons it with 85 Kn engines tejas has a thrust to weight ratio of 0.89,

how much will the emergency bump thrust increase this low TWR with how much weapon weight for how long. Not worth comparing with Tejas mk-1,

So even with no bump thrust mode and even while carrying 1 ton more fuel than the MIG-21 bison tejas has a substantially higher TWR than Mig-21 bison,

But lower wing loading of Tejas will more than off set any advantage for Mig-21 Bisons in this area even without use of emergency bump thrust

Also emergency bump is a feature that is there in all engines not just R-25, We don't know what is the value in GE-404 IN 20,

And cranked delta is a marked improvement over ordinary tail less delta. SO there is no basis for your claim that cranked delta will have drag than the ordinary tailed delta of Mig-21!!!!!!!!!!

This is the first time I am coming across such a bizarre claim anywhere on the net!!!!!!!!!!

Got any source for it? or Is it just a knee jerk reaction?

SO even if Mig-21 bison effectively destroys its engine in a minute of emergency bump thrust , it will still have a far lower TWR than the Tejas mk-1

Add to that the tejas mk-1 's very low wing loading , half that of Mig-21 Bison ther is no way a Mig-21 bison is going to have any edge over tejas in any flight regime in close combat corner speeds.

Add to that,
The Tejas is single-engined multirole fighter which features a tailless, compound delta planform and is designed with "relaxed static stability" for enhanced manoeuvrability,

Originally intended to serve as an air superiority aircraft with a secondary "dumb bomb" ground-attack role, the flexibility of this design approach has permitted a variety of guided air-to-surface and anti-shipping weapons to be integrated for more well-rounded multirole and multimission capabilities

One of the most ambitious requirements for the LCA was the specification that it would have "relaxed static stability" (RSS).

Most aircraft are designed with "positive" static stability, which means they have a natural tendency to return to level and controlled flight in the absence of control inputs; however, this quality tends to oppose the pilot's efforts to manoeuver.

An aircraft with "negative" static stability (i.e., RSS), on the other hand, will quickly depart from level and controlled flight unless the pilot constantly works to keep it in trim; while this enhances manoeuvrability, it is very wearing on a pilot relying on a mechanical flight control system,



Composites in the LCA
The LCA is constructed of aluminium-lithium alloys, carbon-fibre composites (C-FC), and titanium-alloy steels. The Tejas employs C-FC materials for up to 45% of its airframe by weight, including in the fuselage (doors and skins), wings (skin, spars and ribs), elevons, tailfin, rudder, air brakes and landing gear doors. Composites are used to make an aircraft both lighter and stronger at the same time compared to an all-metal design, and the LCA's percentage employment of C-FCs is one of the highest among contemporary aircraft of its class.

The tailfin for the LCA is a monolithic honeycomb piece, an approach which reduced its manufacturing cost by 80% compared to the customary "subtractive" or "deductive" method, whereby the shaft is carved out of a block of titanium alloy by a computerised numerically controlled machine. No other manufacturer is known to have made fins out of a single piece.


The use of composites in the LCA resulted in a 40% reduction in the total number of parts compared to using a metallic frame.

Furthermore, the number of fasteners has been reduced by half in the composite structure from the 10,000 that would have been required in a metallic frame design. The composite design also helped to avoid about 2,000 holes being drilled into the airframe. Overall, the aircraft's weight is lowered by 21%. While each of these factors can reduce production costs, an additional benefit — and significant cost savings — is realised in the shorter time required to assemble the aircraft — seven months for the LCA as opposed to 11 months using an all-metal airframe.

I don't know why all the knaves with knife circle around tejas to taste it's blood?

but I don't mean to be uncharitable to an old war horse like Mig-21 , read more about it's exceptional abilities in the link below,

Making the best of MiG-21 - Defense Technology & Military Forum

But tejas will score over it in every department and Tejas mk-2 version is literally grippen NG equivalent.

So why should people who don't know anything on Tejas always run it down for no reason. It is pretty much a standard operating procedure across all threads here!!!!