HAL Tejas Jet Fighter

Here are some snippets from my conversations with ADA guys at AI-'15. Once again a long post, but I wanted to put it all down before I forget these points.

-Navy LCA Mk2 is not going to be derived from the IAF LCA Mk2. This was made clear by a young gentleman. He said that ADA and the Navy decided to go with a design to meet the IN's needs, even if it means somewhat radical changes from the IAF LCA Mk2, which is further ahead in design phase. The Navy is fully supportive of this approach. They want a variant that works best for their specific needs and requirements, even if it takes more time and effort.

-Navy LCA Mk2 first flight targeted for end-2018 or early 2019 and entry into service by 2023-24.

-The reason for the hump behind the cockpit canopy is due to area ruling. Spoke to a very senior ADA person who works primarily in aero and was associated with the Tejas program since its inception days and he confirmed this. He mentioned that this was done in close consultation with some consulting agency- most likely Airbus Defense and Space (previously EADS), but this he didn’t confirm.

- I asked if the design could be more streamlined or a bubble canopy like that on the MiG-29KUB/K couldn't be used instead of the current design. The gentleman said that the design is not finalised as yet though..further aerodynamic streamlining may occur in the future since they haven't yet tested a wind tunnel model of the Navy LCA Mk2. They will be using the HAL wind tunnel for this, since its considered to be quite good.

-The reason for the hump was that the Navy LCA Mk2 actually has become wider and significantly longer than the Navy LCA Mk1. Add to that the LEVCONS that add to the cross sectional area just fore of the wing join, and they needed a smoother blend and to avoid the sudden cross-sectional area change as seen in the IAF Tejas Mk1.

-That hump will be eventually used for something. Not certain as yet, but likely to be some avionics.

-The reason for the Navy LCA Mk2 having even greater length than the IAF LCA Mk2 was explained to be drag and internal fuel volume related. They wanted more to be carried internally and the designers of the Navy LCA Mk2 wanted to improve the fine-ness ratio.

-I asked the ADA gentleman working on the Navy Mk2 as to why the IAF LCA Mk2 didn’t get a 1m fuselage plug instead of 0.5m and he wasn’t sure..another HAL designer had earlier said that the 0.5m plug was to improve maintainability and access to certain LRUs. Not because of drag issues..clearly, not all folks at ADA and HAL are in the know and their knowledge or info is silo based. They know about their subject but very little about some other department’s issues..I asked if they compare notes amongst each other as the Navy Mk2 and IAF Mk2 groups are different. He said they do know what is happening in each other’s programs but the collaboration may not be very deep.

-The senior ADA gentleman who was associated with the LCA program since the 1980s said that the IAF requirement was for the LCA to be as small as possible and definitely no bigger than a MiG-21.

This confirms what certain other posters on BRF have stated- that the IAF required that the LCA had to able to fit into hangars sized for MiG-21’s and use existing base infrastructure, (while carrying significantly more and to a greater distance). And so the ADA guys went further and made it even smaller in length- the MiG-21Bis length w/o pitot is 14.1m, whereas the LCA Mk1 is 13.2m long without pitot. That was clearly a mistake on the part of ADA and is only now being rectified.

-The reason for the wider fuselage is what we already know- to accomodate the landing gear with its new fairing. Additional fuel tanks will also be accomodated.

-Regarding the F-16 style air-brakes- apparently it was considered but they found it to not be feasible since the structure in that region is not strong enough to withstand the heavy aero loads that will be encountered if the split airbrakes are operated. The beefing up would add weight, so as of now they're going ahead with the current air brakes. However, there is a study underway to see if the airbrake could be moved to a dedicated surface under the wing.

-Harpoon AShM is also going to be integrated to the Navy LCA Mk2 in addition to Kh-35E.

-Derby BVR missile is confirmed for the Navy Mk2 but strangely the person I spoke to wasn’t sure about Python 5. Perhaps he just wasn’t in the know. Another gentleman confirmed that the IAF Mk2 will get both Derby and Python5..he wasn’t so sure about the Astra. By the way I snapped a pic of a Tejas config with the Derby and Python 5, at the Rafael stand..have to figure out how to upload all the pics I’ve taken, which include a bunch of AMCA snaps.

-I’ve uploaded the LCA Mk1 ground based gun firing trials video onto youtube..just search for “Tejas LCA gun firing trial”. It’s a short 5 sec clip. The gun trials were conducted to validate the vibration characteristics and to check whether structures, internal avionics and electronics can withstand it. No issues were seen during the trials.

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-L-273 Uttam AESA radar will be the likeliest radar for the Navy LCA Mk2. This clears my confusion from last Aero India where the Deputy PD said that the Elta 2032 would be the radar on the Navy Mk2. Clearly, 2 years is a long time and lot has progressed since.

-No IRST requirement from the IAF or IN as yet. ADA guy said that they won’t propose new equipment if the user doesn’t have a requirement for it.

-Further work to be done for shaving off another 200 odd kgs from the landing gear weight for the Mk2

-There is no change in the height of the vertical fin. The additional height of the Navy LCA Mk2 has to do with the longer stroke length of the oleos. It just sits higher than the IAF variant.

-Regarding the weights, I’ll post separately.

-N-LCA Mk1 bring back max weight is in the ~10,500 kgs range..with an empty weight of almost 7900 kgs thanks to the beefed up structure, arrestor hook and new landing gear, the corresponding payload that can be safely brought back (coupled with enough fuel for a couple of missed traps on the carrier) will be in the range of ~2000 kgs. Fuel dump system hence is a mandatory feature for the Navy LCA in case of an emergency soon after take-off.But I’m a little hazy on this part of the conversation so don’t quote me on this as the final figures are not in the public domain as yet.

-We will likely see 8G capability for the Navy LCA Mk2 and not 9G. Thanks to the added structural weight over the IAF LCA Mk2. But the gentleman remarked that even the MiG-29K is not 9G capable and the Super Hornet is 7.5G capable thanks in part to the added weight and in part to the wing folding mechanism that they feature. So the IN may have no issues with 8G capability. AFAIK, only the Rafale M is a 9G naval fighter.

-No wing folding mechanism required for the Navy LCA Mk2 even with the additional wing span (viz. thanks to the fatter fuselage) since it is still quite a small aircraft by comparison to other navy fighters

-Navy LCA Mk2 air intakes will be bigger for sure to cater to the higher mass flow rate of the F-414 engine. The air intake duct will also been lengthened.

-LEVCONs for the Navy LCA Mk1 are currently only used in 1 position..but the FCS will eventually allow for 4 positions- +30 deg, 0 deg, -10 deg and -20 deg.

-the LCA Mk1 has ~180 kgs of ballast just aft of the nose, below the pilot. Done to be able to keep the CG within a defined range for different configs of weapons and drop tank loadouts. This may be targeted for reduction on the Mk2, possibly by using the space for some equipment. Got this from a young HAL guy.

-Navy LCA Mk2 will get a fixed probe, not a retractable one as per one gentleman. Last Aero India I was told it would be a retractable one. Unfortunately, Cmdr Sukesh Nagaraj wasn’t there on the day I visited, otherwise we’d have got even more info.

-Currently the LCA Mk1 uses flares similar to what the MiG-21, MiG-27 and MiG-29 (I may have gotten this list wrong, not completely sure) use. It is an indigenously developed flare that works in one part of the spectrum..but a new multi-spectral flare is being developed that covers a wider band for enhanced protection. This will likely be ready for the Mk2.

-Saw a new pylon adapter that has been developed for the Jaguar- to carry, in the words of the gentleman displaying it, “a boxy type weapon” (he didn’t know what it was though, perhaps the CBU-105 Sensor Fuzed Weapon?). The new rack uses pneumatics instead of pyro bolts and consequently is easier to maintain since the pryo leaves behind residue that needs to be cleaned. Plus this one is less than 1/3rd the cost of the imported pylon adapters. I asked him if a multiple ejector rack was being developed and he said no. But if a requirement arose, they could do so.

-Saw the LCA Mk2 cockpit simulator and the cockpit displays. Excellent clarity and they were significantly bigger than on the Mk1. The cockpit itself is a tight fit (I waited for my turn to get to sit inside but some HAL employee’s relatives were given a much longer than usual demo and I was running out of time). The simulator graphics were excellent. Not a full motion sim, but perfect for newbie pilots to get accustomed to the cockpit and the general flying characteristics of the Mk1/2.

-Navy LCA Mk2 will have a wider angle HUD, as it’s a Navy requirement. The IAF has no such requirement, but a new HUD is being developed with better characteristics..not sure what those characteristics are since the person didn’t tell. If jingos want a frameless HUD, ala Gripen or Rafale, they’re going to be disappointed. That ain’t happening.

-HUD symobology is good..been developed in close collaboration with NFTC Test pilots..it took me ~ 10-15 seconds to figure out what was being displayed on the HUD (since it was being displayed on the screen in front of us we all could see it) but that was primarily flight parameters. Since I didn’t get a chance to sit in the cockpit, I couldn’t ask them to run me through different radar modes, or to ask about data fusion or how such data will be displayed. Perhaps it’s too early to ask about data fusion for the Mk2 program. It will most likely be an IAF and IN requirement though.

the Navy LCA Mk1 has demostrated 72 degree nose wheel castering, which is required to move the aircraft in very tight turns while it is on the cramped deck of an aircraft carrier. A small video was being shown for that. I took a pic, will post it sometime.

Will post more as and when I remember it..got a few snippets on the AMCA also.

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