February 04, 2024

Tapas Drone Project Scrapped


IN a shocking development earlier this month, the government made clear its de-funding of the Defence Research & Development Organisation’s (DRDO) mission-mode project to develop the advanced Tapas-BH 201 drone. The Tactical Airborne Platform for Aerial Surveillance (Tapas, also Sanskrit for heat) – Beyond Horizon unmanned aerial vehicle (UAV) was, according to reports till just a few months ago,  nearing preparedness for the final round of field trials prior to certification and thence to production. Among the various armed and unarmed drones being developed by DRDO, the Tapas drone was its flagship project, which had been under development the longest, and was the closest to completion. 

The decision to terminate its mission-mode status, although no formal announcement has been made, was evidently taken not by DRDO itself or by the user services but by the defence ministry bureaucracy and its political bosses. The government decision is said to have been triggered by the failure of Tapas-BH 201 to meet its Preliminary Services Quality Requirements (PSQR) of altitude and endurance. Nevertheless DRDO, apparently supported by the Indian Navy, has bravely declared its intention to pursue the Tapas project till the drone achieved its operational requirements, notably with a view to deployment in the Andaman Islands. However, this would have to be done using DRDO’s own resources since the earmarked mission-mode funds from the department of defence production would no longer be available.

Some commentators have hailed the closure as a decisive step to prevent further “wasteful” expenditure on a failed project. Yet the gap between the performance demonstrated and as specified is relatively small, much has been achieved despite all the weaknesses, and much can still be done to retrieve the project. Therefore the merits of closing the project now at this late stage of technology development, is questionable. More importantly, the scrapping of the Tapas project is a big blow to self-reliance in this crucial area of contemporary and emerging defence technology, and has been seen as such by serious defence experts in India and most international media.  There are also serious whispers in the media hinting at ulterior motives and hidden hands behind the decision.

Admittedly the Tapas-BH 201 drone has had a troubled development phase and continues to be beset by several problems even today. In many ways, this chequered history of technology development mirrors that of other major aeronautical projects in India, in whichever organisation the R&D has taken place. Poor project definition without proper consultation with production agencies and user agencies, often poor initial designs and inflexibility regarding mid-course corrections, single designs and prototypes to save money but therefore narrowing choices and hindering satisfactory outcomes leading to longer gestation periods and higher costs, bureaucratic structures  in R&D organisations, and poor oversight or management by the defence department.

The Light Combat (LCA) project under DRDO was a classic case. Technology development went on for over a decade longer than planned, leading to huge cost over-runs. There were massive tussles between the Air Force, the Aeronautical Development Establishment (ADE) under DRDO and the defence ministry bureaucracy, along with considerable debate (often with ulterior motives) between indigenous development and imported hardware. The project was on the verge of closure several times but somehow came through after successful design-development and demonstration by ADE, finally solid backing by the air force and ministry, to emerge as today’s widely hailed Tejas fighter with several variants of the basic platform, and at downstream indigenous industrial development.

Tapas-BH (also called Rustom-II) development began about a decade ago at ADE after early experimental design, development, flight trials and extensive learning from the much smaller Rustom-I medium-altitude long endurance (MALE) UAV. The Rustom-I itself was a spin-off from the pioneering development of the Light Canard Research Aircraft (LCRA) at CSIR’s National Aeronautical Laboratory (NAL), Bangalore, by a team led by Rustom Damania, taking its name from his after his passing. A much larger Rustom-H variant with a completely new design, larger payload capacity and longer range was then developed fully integrating indigenous avionics, surveillance equipment, autonomous operations systems data links mostly developed by Bharat Electronics Ltd (BEL) and the Defence Electronics Applications Laboratory (DEAL) of DRDO.  The Tapas-BH 201 was then developed by ADE, with some co-development collaboration with Hindustan Aeronautics Ltd (HAL) as the production version MALE drone set to meet the services quality requirements (SQR) of the three services.

The Tapas-BH project obtained approval in 2011 at a cost of Rs 1650 crore with a target of completing development by 2016. Tapas-BH had full-power taxi trials in 2013 but a maiden flight only in November 2016, a longish time but perhaps excusable for relative newcomers to drone development. However, subsequent trials and development for bringing performance up to specifications took inordinately long. It demonstrated autonomous take-off and landing using the indigenous GAGAN system (GPS-aided geo-augmented navigation) system only in November 2021. In end-2021 it demonstrated flight at 25,000 feet altitude and 10 hours endurance, reaching 28,000 feet altitude and 18 hours endurance by mid-2022. But this fell short of the services’ requirement of 30,000 feet and at least 24 hours.

The long time taken, the consequent cost overruns, and the performance shortfalls were due to a combination of factors which, unfortunately, were not addressed in a timely manner or, if necessary, by undertaking major re-casting of the project at an appropriate stage. Put simply, there appears to have been systemic failure in technology management as well as in oversight and guidance by the defence ministry, which have allowed a process of drift till problems have built up to a level almost beyond redemption.

The foremost problem of Tapas-BH has been its weight. From a planned weight of 1,800 kg, itself quite high for a MALE UAV of its size and performance characteristics, Tapas had ended up at an “all up” or total weight of a huge 2,800 kg. Obviously, a drone of this weight would struggle to reach higher cruise altitudes or to attain longer endurance, besides imposing restrictions on the payloads especially weapons that it can carry in an armed configuration.

In attempting to tackle this weight problem, Tapas-BH entered into a classic weight-spiral. Switching to larger, more powerful engines added further weight, calling for strengthening of the aircraft structure adding more weight requiring more power etc.

Some commentators have pointed to the very design of the Rustom-II or Tapas-BH as the root cause of the weight problem. As may be seen from the photograph, Tapas-BH uses a conventional fuselage and wing airframe with two wing-mounted engines, compared to most other contemporary MALE UAVs which have a single-engine twin-boom (SETB) design with a tail-mounted engine with a pusher-type propeller. Without getting into technical details, there are many pros and cons, and it cannot be categorically stated that one design is better than the other. Twin wing-mounted engines are not unknown, but they are usually more common among heavier high-altitude UAVs with larger weapons payloads. In any case, this was certainly one reason for the weight penalty of the Tapas-BH.

A related problem was the achilles heel of many indigenously developed aircraft, namely the selection of an engine, inevitably imported since India has not made any progress in developing any aircraft engine of any type, size or power rating for any application. For the Rustom and Tapas series of UAVs, ADE has gone through numerous options such as the 180 hp Rotax 914 engine, the hugely  popular piston engine used by both the best-selling US and Israeli UAVs, a 200hp Lycoming engine, a 100hp Russian NPO-Saturn turbo-prop engine, and lately the 180hp Austro E4 engine, all in efforts to boost the thrust-to-weight ratio and are now considering a diesel engine being developed by the Central Vehicle Research & Development Establishment (CVRDE) in collaboration with Mahindra. The Project suffered a big shock when China acquired Diamond Aircraft of Austria, makes of the Austro engines, in 2018. (Incidentally, Chinese companies have aggressively used the acquisition route in Europe to access aviation, especially aero-engine, technologies. This method of technology acquisition has not been attempted by Indian private or public sector companies particularly in the badly needed aero-engine sector). 

All said and done, the Tapas-BH UAV remains a viable option, even if some major design revisions and a new power plant are required. Again, without getting technical, many revisions have been made but have succeeded in lowering the weight by only around 220kg according to various sources.

Even the currently proven capabilities of the Tapas-BH UAV are not insignificant. It has achieved altitude of 28,000 feet, just a couple of thousand short of the required 30,000ft, although its already quite good endurance of 18 hours is short of the stipulated 24 hours. It has a good line-of-sight (LOS) range of 250km and 1000km+ beyond-visual-range (BVR) using satellite communications (SATCOM). In mid-2023, the Tapas-BH UAV demonstrated its capabilities over land and sea by first operating from its ground control station in Karnataka, then with controls transferred to a naval ship off the Karwar base flying at over 20,000 feet for over three hours. The Indian Navy is interested in deploying Tapas-BH drones in the Andaman Islands for surveillance and tracking operations, taking advantage of Tapas’ ability to operate from relatively short runways s are available in the islands.

The point is to persist with the Tapas-BH MALE UAV Project in one form or another, and not throw the baby out with the bathwater. A huge amount of experience has been gained during the development of the Tapas-BH which will come in very useful in future development of a range of drones for different contexts and applications. DRDO is already well into development of the Archer-NG MALE UAV with a SETB design derived from the Rustom-I, and also a flying-wing jet-powered UAV. The Tapas-BH Project has also seen development of strong industrial linkages with over 70 percent indigenous content, all of which will contribute to a strong indigenous UAV industrial base. Instead of scrapping the Tapas-BH Project in the Mission-mode, the whole UAV Programme should be placed in Mission-mode, synergies should be actively pursued, and programme management in order to advance self-reliance in the important UAV sector. 

This is doubly important at this delicate juncture. Many vested interests are delighted at the scrapping of the Tapas-BH Project and are itching to fill the vacuum. India is a huge and important market for UAVs. It already operates over 200 UAVs mostly Heron-I and Heron-IIs bought from Israel. Discussions are on-going about possible licensed-manufacture of Heron-IIs in India, possibly by HAL. Perhaps that is being kept in abeyance only by the prospect of an indigenous alternative becoming available.

Meanwhile, the Services have used their emergency acquisition funds to buy a small number of Israeli UAVs to cater to immediate needs. The Army has acquired 4 Heron-II SATCOM-enabled UAVs. But the big news, much commented on in defence-related publications, was the handing over of the first of four “India-made” UAVs (two each for the Army and Navy) from Hyderabad-based Adani Defence and Aerospace. These MALE drones named Drishti-10 Starliner are assembled from knock-down kits from Elbit Systems of Israel but are somehow being hailed as a great stride forward in “indigenisation!”

Beware! The vultures are gathering!