AbhimanyuI wish to bring to notice the news report, titled “IAF to add teeth with Israeli missile system” is by Rajat Pandit who reports for the Times of India. It says, and I quote, “Interestingly, DRDO earlier this year declared that the Akash air defence system, with an interception range of 25-km, was now ready.”
The above statement is technically true on it’s own only, and it strongly hints or implies that only DRDO has declared the Akash as successful. It omits out the important fact that the IAF itself gave the clearance after successful “marathon” trials of the same, that lasted 10 days in Dec. 2007. Later, IAF gave orders for Akash squadrons after the trials.
In my view, the above fact that IAF itself declared the Akash successful gave orders, was purposely omitted by Rajat Pandit from the report because it is a “subliminal” tactic to hint that only DRDO (with a “patchy” record) is making the claim and therefore Akash’s successful completion cannot be independently verified.
Thus, reports from the Times of India by Rajat Pandit appear to be misleading and biased in favour of imported arms companies, which in this case are the blacklisted Israeli firms that are the subject of the report. It must also be noted that Rajat Pandit has never reported on the success of Akash’s successful trials of Dec. 2007. I think that his news reports cannot be read with complete credibility.
Reference :-
AbhimanyuSee, I think in this way then IAF will perennially keep on importing fighter planes instead of indigenously developing them. In the name of ‘joint-development’ and ‘offsets’ — which are “euphemisms” for licence production — foreign aircraft will continue to be purchased.
The obvious ‘beneficiaries’ will be local marketing agencies, and integrators/ assemblers/ testers of the imported hardware. At the most, the latter will get to locally manufacture some non-critical components only.
It is acknowledged that Tejas can replace the entire MiG fleet, and not just MiG-21’s. It can also replace Jaguars and Mirage-2000s. Hence, Dr. Natarajan’s estimation of 400 Tejas units for IAF is not practically implausible.
In my view, if management ‘expediency’ and commitment is shown by the IAF, MCA too can make its first flight in the next decade. However, given the ‘tradition’ of easily acquiring fighters by purchasing licence production rights, the PAK-FA was unfortunately preferred over the “risky” MCA. The IAF should have taken the risk of MCA to meet the very long-term goal of total self-sufficiency in defence, for it would only be then that India will truly be a military superpower.
Abhimanyuwhy Dr. Natarajan gave a figure of 400 Tejas was due to some reason ,since jaguars and Mig-27 will be retired from service from 2020-25 onwards there will be large vaccum around 200+ jets more for thier replacement,
coldfire2005, I agree with the above. The entire MiG fleet (not only MiG-21) along with Mirage-2000 can be replaced by Tejas. However, it may remain to be seen if the IAF does not induct Tejas in these numbers to replace Jaguars and MiG-27s on the “pretext” that the Tejas is an ‘LCA’ and so MiG-27/23 must be replaced by another foreign fighter plane that is ‘heavy’. Note that this same argument has prevented the Tejas from participating in the MRCA competition even though it is only 500 kgs lighter than the Gripen-NG.** In my view, instead of MRCA, a cost-effective solution would have been to hire consultancy from SAAB to reposition the landing-gear and increase space for fuel – same as accomplished in Gripen-nG. It can be done on the similar pattern for accelerating flight tests.
Anyway, as any aircraft that can replace the serving MiG-23/27, MiG-29 and Mirage-2000 of the IAF is ‘eligible’ for competing in MRCA, the Tejas should also be considered as the 7th entrant in the MRCA competition (AESA radar for it can be imported separately).
in future Iaf want to maintain few types of jet ,MKI will be workhorse ,while PAKFA a dedicated Air-superority fighter ,MMRCA and Tejas will form the low level Attack and point defence fighters ,since ADA has plans for Two more Block of Tejas in pipeline one being Tejas Block-II and Tejas A
I think that instead of PAK-FA, the IAF must finally commit itself to PAK-FA. The argument that first the Tejas project must conclude before IAF approves the MCA is not valid, because at some or the other period it has to take the “tough” decision to ‘wean away’ from imported hardware and commit to developing indigenous hardware. In the ensuing time-period in which it will lack a fighter plane, thus reducing it’s defensive and offensive capability, it has to be innovative to devise tactics to compensate for the lack of such a fighter. The same has to be done for Tejas vis-a-vis MRCA also, as Tejas will be introduced in the desired form only 2 or 3 years after the IAF’s deadline to begin inducting the MRCA.
Thus, IAF can have 250 MCA units as it’s 5th G fighters, and Su-30 MKI & Tejas in 600-700 total nos. to replace the entire fleet of older MiGs, Mirages and Jaguars acquired in the last century.
I also disagree with the view that Tejas will be a “point-defence” fighter, because it’s total fuel capacity and weapon quantity is equivalent to Gripen C/D and serving MiG-29s of the IAF.
Reference :-
**Refer to the Standing Committee report on Defence 2006, as per which and I quote, “…Air forces like to have light, medium and heavy fighters ….. Tejas is a light fighter meant to replace MiG-21..”
Regardless of the fact that the above ‘doctrine’ is not in practice or even recognized in ANY major Air force globally, this statement was probably used to further the argument for MRCA and ‘restrict’ Tejas to being only a MiG-21 replacement.
AbhimanyuThe following is an excerpt from an interview of Dr. Natarajan, that appeared a few day earlier :-
“We are into a programme for the LCA. What started off as one project has become three: LCA for the Indian Air Force [IAF] and the Navy and a trainer version of the LCA… Naturally, when we draw a road map, we see the fructification of these three taking us to a medium combat aircraft, a multi-role combat aircraft with fifth generation technologies, where there can be commonality of parts with LCA in avionics or radar, and eventually, 15 years from now, building an unmanned aerial combat vehicle [UACV]… I see a good potential to build all together, about 1,000 aircraft, over a period of time. The LCA could be 400 in number for the IAF, 100 for the Navy; the trainer could be 150; the medium combat aircraft 250; and 100-150 for the UACVs.”
In my view, Dr. Natarajan has made very significant statements in the above interview. Firstly, he expresses confidence that the IAF will procure a large number of Tejas units i.e. of the order of 400. This is in contrast to the figure of 200 units that has usually been reported by the media, that too only as a replacement of the MiG-21 fighters only.
Thus, from the above it may be clear that the IAF may finally be adopting the USAF doctrine of maintaining 400-500 planes of 1 single type. These would replace not only the MiG-21 jets of the IAF, but the entire fleet of MiG series of planes viz. MiG-23/27 and MiG-29, and also the Mirage-2000. These planes not only had overlapping functions, but also that on account of being in small groups of 40-80 units, their utility could never be leveraged over the entire Indian airspace, but instead in some “arenas” only.
The benefits of such an arrangement would also result in a much more efficient management of logistics support.
The second significant point made by Dr. Natarajan is that the IAF can induct upto 250 Medium Combat Aircraft. What may be “striking” about this, is that he expressed hope that the IAF would induct the MCA — that too in as large a number as 250 — when in fact till date one has yet to see the IAF publicly making even a “cursory” mention about the MCA. In my view, this “disconnect” between the IAF and DRDO would not only be not beneficial to the indigenous defence industry, but also be extremely detrimental for national security and the objectives of the IAF.
From the above, it may be clear that the IAF has purchased the PAK-FA in lieu of the indigenous MCA, to purposely “sideline” the latter. In order to justify the purchase of the PAK-FA, it has attempted to “veil” it as a “co-development”, as per which it would locally modify it into a twin-seater only over and above the finalized Russian design. According to it, modifying a foreign design into a twin-seater is a “significant task” sufficient enough to be called a 50-50 co-development. This, despite the fact that past precedents of manufacturing a twin-seater from the single-seat variant have consumed far less time and effort than constructing the original single-seat design (examples are Su-27 to Su-30 and Tejas trainer).
It must also be noted that the projected number of just the Tejas and MCAs alone is 650, which is equal to half the current fighter aircraft fleet. In this scenario, it may be unclear what role the foreign purchases like 126 units of so-called MMRCA and Russian PAK-FA are meant to fulfill.
Reference :-
AbhimanyuAs per the website canit.se, the roll rate of Mirage-2000 is 270 deg/s in air combat configuration. It has been vastly surmised that the Mirage-2000 has the highest roll rates amongst 4G fighter planes.
In my view, Tejas must have equivalent if not greater roll rates than Mirage-2000 owing to the design of it’s delta-wing, which is more “evolved” or “refined” than the Mirage family.
Reference :-
AbhimanyuAbhimanyu
LEVCONs are like slats however they have a slight difference and its the angle they can inflect that at negative inflections is really high 30 deg, the F-16 barely gets -2 deg up to my knowledge and do not know if other fighters can get negative inflections, so as such the LEVCONs are different to a regular slat at least to the F-16`s.
The above is inaccurate. As referenced from a technical article earlier, LEVCONs will be pioneered on the Tejas only, as no similar surface has ever been constructed for any prior, existing or planned fighter plane.
As shown earlier from photos, LEVCONs will be placed outward of the wing, and not above the wing like slats. Also, a separate computer shall control their deflection, again unlike slats.
Now the LEVCON does allow better landing capabilities as the canards used on the Su-33 and in that you are right.
As discussed earlier, improving landing approach is but only one of the many capabilities of LEVCONs. They shall also be used to enhance handling at low speeds, increased controllability at high AoA, greater pitching capability, added nose pitch and more instability that is also introduced by canards. Thus, it may have been for last reason that LEVCONs were installed instead of canards.
LEADING EDGE DEVICES
Leading edge devices are designed primarily to delay the flow separation until a higher α is reached. Some common leading edge devices are shown in figure 3.8. Drooped leading edge Movable slat Krüger flap Figure 3.8 SAMPLE LEADING EDGE DEVICES The lift provided from the leading edge surface is negligible; however, by helping the flow stay attached to the wing, flight at higher α is possible. An increase in CL max is realized, corresponding to the lift resulting from the additional α available as shown infigure 3.9.
STALL SPEED DETERMINATION 3.15 Basic section Droop, slat, or Krüger flap Angle of Attack – deg α Lift Coefficient CL Figure 3.9 LEADING EDGE DEVICE EFFECTS Since the α for CL max may be excessively high, leading edge devices and slots are invariably used in conjunction with trailing edge flaps (except in delta wings) in order to reduce the α to values acceptable for take off and landing tasks
The above is accurate. Slats when pushed outward of the wing, increase the wing area and thus delay the flow detachment (they also “claw” slightly downwards and thus act somewhat like forward flaps also, generating vortices). This increases the usable alpha and avoids stall. The 6 slats on Tejas’ wings are primarily meant for this purpose. However, in case of take-off and landing they may not assist as much, because trailing flaps are absent on Tejas.
VORTEX LIFT Vortices can be used to keep the flow attached at extremely high α. Strakes in the F-16 and leading edge extensions in the F-18 are used to generate powerful vortices at high α. These vortices maintain high energy flow over the wing and make dramatic lift
In the current versions of Tejas, instead of canards, a low-swept leading edge called “crank” helps in the formation of vortices, as shown in this photo from side-view (outlined in red colour). When seen from front-view here, a “notch” apparently appears due to the visual effect of the low-sweep of the lower-swept edge.
The crank assists in higher lift co-efficient, and better rolling and bending moments (refer “Radiance of Tejas”). It may be noted that like LEVCONs, this feature is also not visible in other fighter planes.
[B]ask your self why leading edge slats and trailing edge flaps can not be used simultaneously in an aircraft like the LCA?
The above as just mentioned, is because trailing flaps are absent on the Tejas.
In the airplane’s normal range of flight attitudes, if the angle of attack is increased, the center of pressure moves forward; and if decreased, it moves rearward. Since the center of gravity is fixed at one point, it is evident that as the angle of attack increases, the center of lift (CL) moves ahead of the center of gravity, creating a force which tends to raise the nose of the airplane or tends to increase the angle of attack still more. On the other hand, if the angle of attack is decreased, the center of lift (CL) moves aft and tends to decrease the angle a greater amount. It is seen then, that the ordinary airfoil is inherently unstable, and that an auxiliary device, such as the horizontal tail surface, must be added to make the airplane balance longitudinally.
The balance of an airplane in flight depends, therefore, on the relative position of the center of gravity (CG) and the center of pressure (CP) of the airfoil. Experience has shown that an airplane with the centerof gravity in the vicinity of 20 percent of the wing chord can be made to balance and fly satisfactorily.
To overcome the above problem in case of Tejas, the slats slightly “beak” downwards like leading flaps, when the CL moves aft. This is exactly similar to the effect described in the paper of Vigyan research that assists pitch-down motion. Thus, longitudinal stability is assisted.
AbhimanyuThat’s a good question, but do you really want to bet that the decision on the winner will be taken in time? 😉 Then again, the delivery date will affect other competitors to some degree as well, mainly because the IAF seems adamant on getting an AESA radar. Apart from Lockheed and Boeing, none of the other participating manufacturers has introduced this technology into mass production – all of them have flown demonstrator arrays but they’re still in various stages of testing at this point.
Assuming the above “delivery deadline” of 2012, I think that the only detriment against Tejas’ consideration as MRCA is that, as it will have been installed and tested with new 90 kN engines by 2014, it cannot meet the deadline of 2012. In my view, the IAF can take a step to allow a delay of only 2-3 years in order to give it a chance also.
Anyway, given the general history of highly delayed and protracted defence contracts, like AJT (quarter century) and even delaying the sending of the RFP for MRCAs, the ‘deadline’ of 2012 is unlikely to be met.
I think for India’s long term indegenisation prospects, IAF must burden itself with some risk to delay the deadline for MRCA in order for Tejas to participate in it. Active engagement with DRDO, and a complete overhaul in management can accelerate Tejas’ development. As an example, though AESA radars have been proposed for Tejas by Eurofighter consortium, as per a recent assessment, they may be installed on Tejas only as late as 2025. However, such an estimation must have been made assuming the current rate of low funding, and rate of work (due to management conflicts between ADA and IAF). It is likely that proper managerial “vision” can result in Tejas getting an AESA radar 10 years earlier itself — which is a key requirement for MRCAs.
Another detriment in Tejas being viewed “skeptically” is that it has been “labelled” with various terms like “point defender”, “Light aircraft” etc. Such attributes are not regarded for Gripen C/D, which has similar empty-weight, and same weapons-stations and fuel capacity as Tejas.
AbhimanyuAs mentioned earlier, the Tejas can carry the standard payload –by weight as well as variety — of 2-3 tons like the F-16 or F-18, that are useful for all types of conventional combat missions. Being proportionately lighter, it’s combat radius should also be similar to Gripen NG or F-16. The only difference between Tejas and the MRCA contenders is that because it’s weapon loading is not of the order of 8-9 tons, it cannot carry cruise missiles and some heavy types of nuclear tipped warheads.
Gripen-NG can carry 40% more fuel in order to accomodate the loading on 2 extra pylons and a heavier engine. In range-payload specifications, it is thus closer to F-16 only.
Again, many MRCA contenders themselves are “on-paper” only. As an example, MiG-35, Gripen-NG are very recent entrants (though have a tested history of earlier variants) and the Typhoon got a certain certificate for weapons firing only this year. It is doubtful whether it has even reached the equivalent of IoC/FoC within the EU itself.
Now as mentioned earlier, as regards the F-22 it was part of a definite vision to procure a 5th G plane, whereas JSF ”ended up” as 5th G because it was the “natural evolution” to 4 & 4.5 planes like F-15, F-16 and F-18 (naval as well as terrestrial). In contrast, other countries do have a vision of a separate fifth G plane — akin to F-22 — but do not immediately plan to replace older planes by a 2nd 5th G plane, but by more like 4+++ plane. The latter example is that of Russia vis-a-vis planned Su-35 and variants, and EU & UK vis-a-vis Typhoon. In fact for UK, F-35 and Typhoon are in the same proportion as F-22 and JSF are for the US.
Similarly, India may “ill-afford” a 2nd fifth G plane for replacement of older MiG series and Jaguars. The IAF has envisaged the MRCA primarily for this purpose, but I think this can also be done possibly by Tejas itself and more Su-30/35 variants. The vision for having 5th G planes must be there — as it is with Russia, China, Australia etc.– but it must be fulfilled by MCA instead of a foreign plane. IAF may also specify the relatively ‘minor’ change of a twin-seat/trainer MCA also, if it so needs.
From all available reports and Mr. Fakruddin’s interview, the PAK-FA will be to India what JF-17 is indeed to PAF i.e. a foreign aircraft with local licence rights only. However, as in case of Su-30 MKI, IAF had major custom-components indigenized, whereas PAF seeks the same custom-components from Europe. Thus, PAK-FA is not different from Su-30 model of development at all.
I think there is still time for IAF to exit from the yet unconcluded negotiations with Russia, because once signed finally, it can be difficult for IAF to extract it’s customizations from PAK-FA. This is because there will be terms and conditions as to what India will be restricted and prohibited to modify on PAK-FA, and it’s expectations (except that of a twn-seater) are likely to “fall short”.
If begun early now, the IAF can dedicatedly and teamingly work alongside DRDO to develop the MCA. As per Dr. Natarajan, it can be developed in 15 years’ time, and as per Mr. Pranab Mukherjee’s statement in Parliament in his capacity as Defence minister, India could seek assistance where needed on MCA (similar to Tejas’ model of development).
AbhimanyuAs it is known, Tejas in it’s present configuration is equivalent to Gripen C/D in weight, loading, internal fuel and is very likely to be so in range also. Though it is true that Gripen-NG has 2 more weapon stations than Tejas, it may not justify a totally new and unfamiliar purchase. Thus, Gripen-NG can be substituted by Tejas and as the Gripen-NG is deemed “fit” to be an MRCA contender by IAF, so can the Tejas.
Regardless of the fact that Tejas after addition of 90 kN engines may start to be inducted from 2014 onwards, a 2 year later introduction than MRCA in 2012 may not be justified to not consider it as an MRCA contender. In this case, the IAF must also keep in view the development of the indigenous industry also, savings in costs, complete immunity from global sanctions, on-demand availability of support, and total insulation from mid-stream contractual changes, price rises and geo-politics.
I reiterate that although 6 squadrons of Tejas are guaranteed, the IAF must induct — in addition to these 6 — a further 126 not only in order to avail of the benefits listed above, but also because it would assist in meeting the strategic requirement of “global strategic reach” by augmenting the number of Tejas units to 350. Further units must be procured to increase the number of serving units to 400-500. In this manner, the cost-effort of maintenance, inventory, logistics may also be “drastically” reduced.
Now, it is true that “evolutionary process” in USAF has resulted in the replacement of F-16 & F-18 units to be the JSF, which had to be 5th G (otherwise replacement would have been redundant). The F-22 on other hand, was a result of a purposeful strategic need of a 5th G plane. However, in this regard India may emulate Russia, where older MiG-29, MiG-27 etc. will be replaced by more “modest” Su-35 and variants thereof and only 1 type of 5th G plane is part of the purposeful 5th G strategy.
Now, as regards the fifth G plane for IAF, the issue is developing an indigenous 5th G plane to further our aviation industry and also to “sever” and “wean” away from the perpetual dependence of highly expensive, foreign planes (this is regardless of whether the MCA’s induction is guaranteed over and above PAK-FA).
Otherwise, even currently India can now openly afford the purchase of a few squadrons of PAK-FA and JSF (Lockheed Martin made a presentation of JSF to the IAF recently).
The advantage of procurement of the MCA in place of the PAK-FA is that IAF will not have to bear the high costs of purchasing and maintaining 2 types of 5th G fighter planes. The IAF can begin to monitor and assist the MCA beginning now itself, just as it began “patronizing” the as yet unknown, unflown, unproven and on-paper PAK-FA.
It is for this reason that Tejas’ completion as a prerequisite to subsequent attention to MCA is an invalid reason to not pay attention to MCA presently.
But the single most important benefit in procuring the MCA is that the IAF will be able to ‘mould’ it from the drawing board itself. Every small requirement in MCA can be tailor-made to “perfection” keeping in mind the IAF’s tactical as well as strategic vision. It may be similar to a tailor-made suit in comparison to a ready-made one. This advantage CANNOT be provided by PAK-FA, which as per reports has been exclusively designed, frozen and put into production without an “iota” of IAF’s requirements, needs and expectations. It has been designed and already put into production solely as per the ASRs of the Russian Air Force only.
The statements by Mr. Fakruddin were not in congruence with what the IAF and MoD have claimed since 2006. As per his interview, he was unsure about India’s percentage of workshare, uncertain about when India would “sign the dotted line”, and thus “salvage” the remaining possible work-share. Besides, he categorically stated that India will limit it’s contribution to testing, integration of components, navigation systems and engine change only. He also admitted that the Russian side will NOT incorporate Indian changes; changes that will be limited to avionics and engine, which in effect implies that PAK-FA is exactly like the Su-30 MKI which was only customized for India instead of being “jointly developed”.
Thus, in total negation of what the IAF and MoD have falsely claimed since 2006, the PAK-FA to India may be akin to what JF-17 is to Pakistan : a 100% foreign aircraft to be licence-produced locally. In my view, the public claims of 50% “joint development” must be retracted, and a purchase agreement must be declared to the public.
Again, the IAF may as well inquire about a twin-seat MCA also if a requirement for a twin-seater is present. As India is yet to enter the PAK-FA group, and as it is yet to make it’s debut flight, it may be far more tedious and time-consuming to transform a single-seater into twin-seater than to develop a twin-seat MCA (along with single seat version) from the beginning itself.
AbhimanyuMan number one the article you quote all the time has no picture or illustration, so the so called LEVCON conection was made by me, not by the article, since both have different names, one article calls them LEVCON and the other wing apex fences so we have no certainty both are the same thing.
The article posted by me has a frontal photo of N-Tejas, on which LEVCONs are not clear. A clearer photo of the same is seen in this photo from DefExpo 2004. Again, the plan of addition and various photos of addition of LEVCONs on N-Tejas has been well known since 5-6 years now at least, whereas you may have known about it now only, in the course of this discussion.
As repeated earlier, terminology may not matter in this case as LEVCON and Apex fences are not recognized terms in standard aviation, because they are the particular proposals by individual organizations only.
The use of the LEVCON is as a slat and it works by deflecting the leading edge and keep its vortex attached to the wing upper surface, same as a slat, negative inflections are only useful to reduce drag as the F-16 does and create a supersonic profile.
The above is inaccurate. That LEVCON is a slat is a misconception, because official and unofficial publications clearly distinguish between the LEVCONs and present slats. Thus, as per as per the article “Radiance of Tejas”, mention that and I quote, “No such feature exists on any aircraft in the world”, end quote. Slats may be found on other fighter aircraft also, but not LEVCONs.
Please note that slats are not the equivalent of canards, whereas LEVCONs were supplanted after canards were removed from the Tejas.
Now, LEVCONs differ from slats thus :- As per the same article and as seen in the photo posted above, LEVCONs are not placed above or under the wing’s leading edge like slats, but are fully outside of the edge. Also more importantly, unlike slats LEVCONs will be under the pilot’s control and will have a separate computer to operate the same. Globally, slats in fighter planes are not under pilot’s control.
Why then the LEVCON is used in landings?
As per articles from acig.org and “Radiance of Tejas” posted earlier, LEVCONs will not only be used during landings, but also to increase controllability at high AoA and optimal use of instability.
Reference :-
AbhimanyuAbhimanyu
According to the paper the LEVCON is device to help in landings, therefore it has been implemented on the naval LCA only.
The above is inaccurate. As per this article from DefExpo 2004, New Delhi, the LEVCONs have been described as, and I quote, “The LEVCONs will however, be retained and along with a higher thrust to weight ratio, will help the naval variant exceed the conventional LCA’s AoA and turn performance“, end quote.
The website from which you have quoted is not a paper, but the website of an enthusiast of Tejas (if I’m not mistaken, he also posts on this forum).
You are affirming something which is unaccurate, the ADA document says simply SLATS and the LCA has slats not wing fences, now if you refer to the Naval version it says LEVCONs not wing fences.
I reiterate again that the paper from Vigyan research proposes 2 solutions : apex fences and apex flaps. The slats are not apex fences, because though they meet the description of “spoiler-like surfaces hinged on leading edge”, they are not “deployed verically”. Hence, instead of apex flaps, earlier I mistook them for apex fence. However, as it still is one of the 2 solutions proposed in the paper, the aerodynamic problem is solved.
Now the LEVCONs finally meet the description of being “deployed vertically” and hence are the equivalent of apex fences described in the paper.
Now as discussed earlier, the slats are somewhat similar to apex wing flaps, because when extended outward, they “pout” downward thus behaving like a LE flap to an extent. As per the article, “Radiance of Tejas” posted earlier, the slats assist in generating vortices at high AoA. In the paper from Vigyan research, this solution is the other solution to apex wing fences (LEVCON) that also serves the purpose of generating vortices at high AoA, besides providing some counter-moment about the CG to assist elevons.
The LEVCON still is part of the wing and its part of the main wing root and is basicly a SLAT; the canard it is not, the canard generates its own vortex which does interact with the wing`s vortex, has the trimming function done in the LCA by the elevon plus extra lift in a second center of lift ahead of the CG
The above is inaccurate. As discussed above, the LEVCONs meet the full description of “spoiler-like surface, hinged on leading edge and deployed vertically“. The slats do not meet the description of underlined part.
AbhimanyuIn my view, as the Su-30 and Tejas perfectly complement each other in combat roles, there may not be any need for a so-termed “medium” MRCA. Thus, the 126 Tejas units must be inducted as the MRCA. Similarly, as all 5 gen. planes have similar range-payload capabilities (based on global “trend”), PAK-FA may not be necessary.
Though it is true that MRCA’s induction will not “hamper” the induction of Tejas planes (200 of which are guaranteed), the Tejas must also be inducted in 126 nos as the MRCA. This is not only because it meets all MRCA requirements (except carriage of cruise missiles), but also because streamlining of the variety of types of planes, and global strategic reach may require that 400-500 fighter planes of a single type be inducted — as is the case of USAF, PLAAF etc. The latter may be important against numerous “bunches” of 40-60 or 80 planes of one type in the IAF currently.
Similarly, even if assuming that MCA’s induction may be guaranteed independent of PAK-FA, the MCA only must meet all fifth G requirements and the PAK-FA must not be inducted at all. It must be noted that Russia, UK, France, China, Australia, etc. are committed to one fifth G fighter plane only. In the exceptional case of US, multiple programs for a single purpose like 3 types of BMD, 2 types of fifth G planes and multiple types of bombers may be more due to the result of a natural ‘evolutionary’ procedure, rather than a purported or definite “vision”. In my view, corrupt defence planners in Indian Army and IAF are using the US practice of multiplicity as an “excuse” to justify REDUNDANT proposals/purchases like Patriot (despite successful tests of BMD), PAK-FA (despite MCA being on drawing-board since 8 years) and medium range missiles (regardless of Akash’s success).
In my view, the IAF is deliberately “ignoring” the MCA in favour of a foreign purchase. What may be “appalling” is that as per a top HAL source himself, there is not only total uncertainty on India’s percentage of workshare, but also indecision over exactly what India is supposed to “modify” (read: ‘tinker’) on the PAK-FA. This was in total contradiction to what MoD and IAF have communicated to media since past 2 years namely 50% joint-venture, 50-50 development etc. Mr. Fakruddin’s statements were “shocking” to say the least.
AbhimanyuAbhimanyu
I am not an aerodynamist and i am still learning, i think the LEVCONs seem to be the closest thing to a apex wing fence i can imagine if i try to agree with you, however the LEVCON is not called Apex wing fence, but perhaps later i can confirm you if they are or are not but they seem to be the same.
See, the terminology may not be relevant in this case, as ADA and the Vigyan Research Inst. have separate nomenclatures. It must be noted that LEVCONS and Apex Fences are NOT widely accepted terms like wings, flap, or slats. They are particular ideas/implementations only.
However i disagree in one aspect with you, if the LEVCON and leading edge notch increase lift according to the LCA`s needs, i do not see their advantage beyond lift and stability at high AoA.
As discussed earlier, the Vigyan Inst. has in the same paper, refered to an earlier suggestion to achieve the same objective i.e. to provide for a counter-moment to the elevons in the event of the CG shifting it’s location more aft. This suggestion was apex flaps, whose function is executed by Tejas’ slats also, as they also “pout” downwards when extended outwards. Thus, the objective of the paper is met by the current Tejas versions, and LEVCONS may be the implementation of apex fences.
Besides LEVCONs are not part of the LCAs that have been built up to now.
Note that Naval Tejas has commenced production already.
AbhimanyuThe issue of wing fences has been discussed in the thread, “New & emerging fighters from Asia”.
In my view, the LEVCONs that have been proposed for the Naval Tejas are a new type of fence that was first proposed in a research paper by an Indian research Institute. The abstract proposes an apex fence, that is hinged on the wing’s leading edge, and which is vertically deployable. The purpose of this would be to provide a counter-moment to assist the elevons in supersonic regimes, when the CG shifts further aft.
As per the article, “Radiance of Tejas”, and other articles, the Naval variant of Tejas shall feature Leading Edge Vortex Controllers (LEVCON). These are fully controlled surfaces on the Tejas’ leading edge, which shall be deployed for vortex generation. It must be noted that this feature has never been implemented on ANY plane previously in the chronology of military or civil aviation.
In my view, LEVCONs may “aptly fit” the description as provided in the research paper.
References :-
1) Low speed aerodynamics of APEX FENCES on a Tailless Delta configuration, Vigyan Research Institute
2) Radiance of Tejas, (refer LEVCONS)
AbhimanyuMiG-23 MLD, as mentioned earlier the research paper from Vigyan Inc. mentions that it’s suggestion is a spoiler-like surface that extends over the wing’s leading-edge and which deploys vertically. The same is the description of slats, with the exception that it does not deploy vertically unlike the paper’s requirement.
Note that the paper has made a second suggestion of apex-flaps as the solution to the same problem, which is fulfilled by slats. Thus, regardless of the absence of apex-fence (in lieu of apex-flaps instead), the same aerodynamic problem stands fully solved on the Tejas.
Now, as the proposed LEVCONs on the naval Tejas will be vertically deployable, they will in fact be the “faithful” implementation of apex spoiler-like surfaces (apex fence) as mentioned in the paper.
I figure it would be better to post this here than to start a new one.
Google translated from http://hi.baidu.com/liliqun/blog/ite…cbe09e698.html. It has a what-if image if a ROK fighter on the page too. The article is a year old. Also talks about other asian fighter projects.
Loofahboy, in my view, as indicated in the article, Taiwan’s proposed fighter is likely to be a conventional fighter with indigenous RAM coating only.
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