Flying & fighting in the HAL HF-24 Marut: Interview with IAF pilot Vijainder K Thakur

 

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Following the defeat of nazi Germany, the aircraft designer Kurt Tank — creator of the world-beating Focke-Wulf Fw 190 — went to Argentina. Here he worked on jet fighters, before heading to India with a great deal of research material. Hindustan Aircraft Limited (HAL) worked with Tank on an exceptionally sleek new fighter, the Marut. Seldom remembered, and when recalled often written off as a failure, the Marut actually had the potential – but not the requisite good fortune – to have become an exceptional machine. We spoke to former IAF pilot Vijainder K Thakur about flying and fighting in Kurt Tank’s final fighter. 

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Vijainder K Thakur

 

Which three words best describe the Marut?

“Pretty, Promising, Played.”

What were your first impressions?

“Having already flown the Hunter, a similar class aircraft, at Operation Conversion Unit (OCU) the move to Maruts wasn’t daunting. The Hunter had a better thrust-to-weight ratio than the Marut. However, the Marut’s supersonic design, spacious cockpit and pleasant cockpit interiors looked inviting. There was also the hope that the aircraft would get a better engine gaining speed and punch.”

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 What was the best thing about it?

“Good low-level handling – fast and responsive. We could clock 620 kts at 500 ft in the late production (extended chord) D series and around 650 kts in earlier BD series. Twin engines ensured safety from bird hits at low levels and a spacious cockpit facilitated map storage and reading. “

And the worst thing?

“The large number of technical issues that plagued the aircraft. The Marut’s high pressure (4000 psi) hydraulic system was prone to failures. Backup manual controls mitigated the impact of such failures but there was always the fear of the leaking hydraulic fluid catching fire. There were several cases of compressor blades rubbing against engine casing leading to catastrophic failures. Poor HAL workmanship caused fatal accidents such as canopy jettisoning failure!”

 How do you rate the Marut in the following categories?

A. Instantaneous turn

Good at low levels, with turn rate limited by G limit.

B. Sustained turn

Reasonably good at low levels as long as you didn’t excessively bleed your speed below 420 kts.

C. High alpha

Sluggish but safe.

D. Acceleration

Good at low levels up to speeds of around 580 kts. Poor at higher altitudes.

E. Climb rate

Good at low levels.

When did India procure the Marut and where were you trained?

“The Marut was operationally inducted into the IAF on April 1, 1967 at  Armament Training Wing (ATW), Jamnagar with the standing up of No. 10 Squadron (Daggers), which had been number-plated since April 1964. The squadron was raised with 12 prototype and pre-production Maruts and two Hunter T 66 trainer aircraft. Prior to their operational induction, these Maruts had been test flown and evaluated by the IAF’s Aircraft and Armament Testing Unit (A&ATU), the predecessor to the present day Aircraft and Systems Testing Establishment (ASTE). The initial batch of Marut pilots underwent pre-solo conversion on the Hunter T 66 trainer aircraft practicing take-offs, circuits and landings flying at speeds and using patterns and glide slopes identical to the Marut. Within two months of operational induction, there were two major Marut accidents – a fatal crash and an ejection.

After requipping and becoming operational with Maruts, No 10 sqn took on the role of Marut training squadrons and helped raise two additional Marut squadrons – 220 (Desert Tigers) and 31 (Lions).

Around May 1969, 10 squadron moved from Jamnagar to Pune; shortly thereafter, 220 sqn was raised from pilots and aircraft that had accreted to 10 sqn since its raising. The two Marut squadrons moved to Jodhpur in December 1970.

“The Marut was built tough. Dr Kurt Tank designed the Marut to be tough enough to slice a tree in half with its wing… its fin could cut through high tension cables with just a gash to show for it. A gash that could be easily repaired to preclude raising even an incident report or linking it to a massive power failure south of Jodhpur!”

What was its combat record? 

“During the 1971 ops, 10 and 220 squadrons operated from Jodhpur and proved their mettle flying Close Air Support and Interdiction missions. Three Maruts were lost to enemy ground-fire.

The Maruts reportedly flew around 300 sorties during the 1970 Ops. Those who participated in the ops feel that the aircraft was grossly under-utilised. For example, its very potent 30-mm Aden cannon and T-10 / Matra rockets, and the safety accruing from two engines, could have been used to augment the firepower of the Hunters at Longowal. The reason why Op planners overlooked the Marut was probably lack of knowledge about the aircraft’s performance and capability!

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Besides ground attack, Marut scored one air combat kill without any air-to-air losses. The air combat kill was claimed by Sqn Ldr KK (Joe) Bakshi when his strike mission was bounced by four PAF Sabres resulting in a melee.

Joe was pulling out of a strafing run when he saw a Sabre flying across his bow at close quarters. His finger on the trigger already, Joe reacted instantly and fired his twin 30-mm Aden cannons at close quarters as the Sabre disappeared in his hind quarters.  Flt Lt KP Sreekant (later Air Vice Marshal) was part of the same formation. He was trying to gain positional advantage on a Sabre ahead when he saw another Sabre criss-crossing trailing black smoke. Joe was awarded the kill based on an R/T call made by KPS about the Sabre trailing black smoke, since there was no way of physically confirming the kill.

The 3rd and final squadron of Maruts was raised in 1973 with 31 sqn (Lions) converting from Mystères to Maruts.

I was posted to 10 Sqn in end 1975 for my type conversion, after I completed my training at Operational Conversion Unit (OCU) in Kalaikunda, West Bengal. Post conversion, I moved to the Lions where I remained until 1981 logging around 650 hrs. During my tenure, the Maruts were grounded over safety issues for long spells on two occasions and for short spells on several occasions. The total grounding period was around 1 yr 6 months.”

What was your most memorable mission?

I readily recall three missions – two of them out of a sense of accomplishment and the third out of a sense of the bizarre.

In March and April 1979, while preparing for a forthcoming DASI (Directorate of Air Staff Inspection) visit, our CO, Wing Commander SK Sonpar (Stona), put the squadron through the hoops with DACT. We worked meticulously – planning and sketching coordinated manoeuvres to ward off Type 77 (MiG-21) aircraft attacks, practiced the manoeuvres, and spent hours debriefing. In April 1979, I flew several DACT 2 vs 1 combat sorties with  Type 77 aircraft which felt so much more real than practice with a Marut as attacker. Our ability to hold our own through early spotting and teamwork gave me a lot of satisfaction and confidence.

Flt Lt VS Kochar (Koch) and I volunteered to take on the DACT exercise with the two of us executing a coordinated strike and a DASI inspector in a Type 77 bouncing us.

A fatal accident on range cut short the DASI visit and we never got a chance to shake down a DASI inspector in a T-77. Word about our squadron’s intensive DACT preparations must have reached the ears of DASI inspectors because they assessed the squadron as Average plus based purely on the squadron’s performance on the range. The DASI could have opted to withhold a rating and make another visit.

In October and November 1979, ahead of South Western Air Command (SWAC) inter squadron steep glide bombing competition, our squadron started working on the theory and practice of steep glide bombing, determined to win the trophy.

The key to accurate steep glide bombing is getting the 45-deg dive right and the Lion bombing team comprising Stona, Sqn Ldr SK Sanadi (Sandy), Sqn Ldr KR Singh (Keru), Flt Lt James Sebastian  (Jimmy) and self initially perfected our dive angles by doing bombing runs over the Jodhpur runway, using the R/W markers as accurate cues.

Later, we practiced on Pokhran range. Eventually, it was time to practice with live bombs. The effectiveness of our mathematics based training surprised us. Hitherto, steep glide bombing had been notorious for large errors upto 100 yards. When we started dropping bombs, we didn’t drop one more than 20 yards off. Typically, the bombs dropped on the Bulls eye or within 10 yards. No other SWAC squadron stood a chance. We won the trophy easily.

The bizarre mission that I referred to wasn’t planned. In March 1979, I had just completed a front gun firing dive at Pokharan when I got a R/T call* from Jodhpur ATC. 

“83, Jodhpur”

“Jodhpur, Go ahead”

“83, Have you finished your ammo”

“Negative”

“Roger, make your guns safe. Wait for 33 SU instructions.”

“Roger”

“83, this is 33 Su.”

“Go head”

“Climb to 10G and steer course 270 for interception. Check your fuel state.”

“Good for 20 mins loiter”

I don’t remember the fuel that I had. I was flying in clean configuration and Jaisalmer wasn’t far. So I told the radar I was good.

Having settled on an interception course that was very obviously taking me towards the Pakistan border, my heart started to beat a little faster.

 

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Lions Steep Glide Bombing Team
L to R : Self, Sandy, Stona, Keru, Jimmy

 

The excitement was short lived. Within a minute 33 SU instructed me to return to base.

The incident happened after a day or two after Pakistan’s supreme court turned down former Pakistan Prime Minister ZA Bhotto’s appeal against his death penalty. Indian intelligence had indicated that Bhutto might try and escape by air to India and apparently 33 SU had picked up a track.

Think about it! With a little bit of luck, I would have made one line nondescript entry into history books!”

Which aircraft have you flown DACT against and which was the most challenging?

“During my Marut tenure, the MiG-21 (Type 77) and MiG-21M (Type 96) were the most advanced fighters in the IAF inventory. Those were the days when the IAF had 30 squadrons of MiG-21s!

Most DACT involved MiG-21s intercepting low-level Marut strikes.

Despite its significantly lower thrust-to-weight ratio, the Marut was no walkover. I will explain why. MiG-21s of yore had intercept radars with no ‘look down’ capability. For intercepting Marut strikes, the MiGs relied heavily on voice vectoring by controllers of ground based radars such as the mobile P-18 VHF early warning radars of 254 SU deployed near Jodhpur. At 500-ft, the preferred cruising height of Marut strikes, detection range was severely limited by radar horizon, while detection quality was constrained by the two dimensional tracking by the radar. Following the operationalisation of 33 SU equipped with the French THD-1955 high power three dimensional radar near Jodhpur the vectoring became more effective.

When MiG-21 vectoring did succeed, Marut pilots were instinctively inclined to stay in their comfort zone – low levels where the aircraft was fleet footed and very responsive. Visually sighting Maruts flying nap-of-the-earth was challenging. It became even more challenging when in the  late 70’s HAL decided to desert camouflage the aircraft.

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Based on the IAF’s air combat experience in the 1971 war, Tactics Development Establishment (TACDE) at Jamnager developed air combat tactics that focused on positional manoeuvring and the Marut squadrons were quick to embrace these tactics. Wing Commander SK Sonpar (Stona), a Fighter Combat Leader (FCL) who commanded 31 sqn from Nov 1977 to September 1980, pioneered the switch to positional air combat from the traditional energy and manoeuvre focused air combat.

No more would you see two Maruts on a strike mission in the same glance. They would be 2-3 kms apart and abreast of each other, ready to quickly sandwich any hostile that came astern of either or both through a simple hard turn. The sandwich would force the attacker to break and give a chance for the Maruts to hit the deck and escape. A four aircraft strike would be spread over 9 sq. kms and a six aircraft strike over 12 sq. kms!

The Marut was a sweet lady, not a bitch!”

Under Stona we developed and practiced tactics that would allow us to attack enemy ground targets  while providing mutual cover and retaining full positional and energy advantage. The effectiveness of our tactics gave us complete confidence in our ability to strike targets despite the threat of superior enemy fighters. The key to the success of our tactics was spotting the MiGs before they closed in to missile / gun kill ranges.

Our confidence levels rose to an extent where we started playing with the MiGs. I remember one exercise; I was part of a formation led by Stona that bamboozled the MiGs by zooming up after striking the target and cruising back to base at 15,000 ft! The hot in-pursuit MiGs missed us completely… they kept looking down while being vectored. The radar controllers at 33 SU, despite the height readouts on their scopes, never realised what was going on! So confident were we of our positional manoeuvring, we didn’t think we were taking a risk by cruising at 15,000ft!

TACDE developed positional manoeuvring notwithstanding, many Marut stalwarts remained convinced that your best bet against Type-77 was to hit the deck and get the hell out of there. It’s indeed moot how accurately  a Type-77 would be able to engage a Marut flying at 200-ft and 620 kts.”

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How good were the sensors?

“Other than its gunsight, the only sensors in the aircraft were our eyeballs and trust me they were very good because our lives depended on them. We maintained them in perfect order through exercises! To begin with, the Marut had a gunsight similar to the Hunter. The D variants, that I flew, had an ISIS gunsight that was very stable and accurate.”

How easy is to fly? What is the hardest thing about flying it?

“The Marut was easy to fly with reasonably good cockpit visibility. The controls were responsive during the entire flight envelope. Departure of any sort was unheard of.

As per the SOPs, you were required to enter a looping manoeuvre at around 460 kts, an embarrassingly high speed for a fighter aircraft. To increase pride and confidence in newcomers, Marut stalwarts like Sqn Ldr SK Singh experimented and progressively reduced entry speed. Eventually, Marut pilots started entering a loop at 350kts. On top of the loop, the speed would drop to around 60kts but the aircraft would go around with ease, sluggish controls notwithstanding.

Pilot error accidents in Maruts were rare and always on account of misjudgement, not failure to extricate the aircraft from a departure. The Marut was a sweet lady, not a bitch!”

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Is the cockpit tiny?

“The cockpit is spacious and well laid out.”

How would you rate the cockpit?

“Excellent. Perhaps roomier than required! Each and every switch or circuit breaker is easily accessible.”

Have you fired live weapons – if so, what was it like?

“Besides its twin 30-mm Aden cannons, the Marut could carry T-10 rockets and 1000-lb bombs. Dr. Kurt Tank designed the Marut as a twin seater. In the fighter variant the rear seat was replaced by retractable stack that could hold around 50 Matra rockets! Yes, it had an internal weapons bay! Later, before I joined the Maruts, carriage of Matra rockets was discontinued and the rear cockpit space was utilised to carry extra fuel. 

Post 1971, HAL attempted to fit 4 Aden cannons on the Marut. The attempt was abandoned following a fatal accident during trials over the sea, when excessive vibrations caused the aileron lugs to get detached causing the aircraft to roll into the sea.

ASTE tested the Marut with S-24 stand off rocket bombs but by the time I left the fleet the weapon had not been inducted into squadron service.

Gun and rocket attacks involved shallow 12-15 deg dives, but bombs had to be released in a 45-deg steep glide because they were not retarded. The attack profile involved zooming up to 15,000 ft and bleeding speed to around 250 kts, throttling back and then rolling into a kamikaze like dive hanging by your straps under zero g, and positioning the gun sight on the target catering to calculated wind induced drift. Once settled in the dive, the heavily laden aircraft would accelerate rapidly, the altimeter would start to spin down crazily and tracking with the gunsight would become challenging. Releasing the bombs at the right height, irrespective of the state of your target tracking, was critical because in case of release failure you would be pulling out of the 45-deg dive with 2000 lbs more than you planned!

After 1971 ops, HAL attempted to arm the aircraft with four 30-mm Aden cannons instead of two. During the gun trials we lost a test pilot when because of excessive vibrations aileron lugs got detached and the aircraft rolled into the sea. This issue was never fixed and the aircraft was limited to firing two guns at a time and later the two outer guns were removed.”

What is the greatest myth about the Marut?

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“That the aircraft didn’t meet expectations. The aircraft met expectations, the project didn’t! Because MoD never put into the aircraft the engines that the aircraft was built for.

When I was posted from Maruts to Jaguars in 1981 it dawned on me how hopelessly doomed the Marut had become. Aviation technology had moved so far ahead while HAL had struggled to fix Marut manufacturing shortcomings.

The future doesn’t depend on what you do today. It depends on what you did yesterday. What you do today depends on the follow-up required on what you did yesterday.  How long could the aircraft remain relevant with the 1952 vintage Orpheus 703 interim engine?”

 How combat effective was the Marut?

“The Marut’s limited range and weapon load didn’t make it a very effective combat platform. I don’t believe the three Marut squadrons were ever a great worry for the PAF. The aircraft had the potential to become a great worry for the PAF. That potential was never realised.”

You may also enjoy interviews with pilots of the following IAF types: MiG-21MiG-25, MiG-27, MiG-29, Mirage 2000 & Su-30 ‘Flanker‘ and PAF types: MiG-19, F-86 Sabre, JF-17 Thunder.

How reliable and easy to maintain is it?

“In the 650 hrs that I flew the Marut, I didn’t encounter a single technical failure. During the 425 hrs that I flew the Jaguar I had an engine fire that mandated a single engine landing. Going by my own experience, the Marut was as reliable as any contemporary fighter. But there is no denying that Maruts were plagued by technical problems that led to frequent loss of life and write-offs.

There were no serious maintenance issues. The Lions operated with 100% serviceability on many occasions during my tenure, even when we had more aircraft on strength than the establishment. The fact that HAL technicians were always on hand to help fix issues was a factor.”

Tell me something I don’t know about the Marut

“The Marut was built tough. Dr Kurt Tank designed the Marut to be tough enough to slice a tree in half with its wing! I don’t believe that capability ever came to be tested, but Marut pilots know for a fact that its fin could cut through high tension cables with just a gash to show for it. A gash that could be easily repaired to preclude raising even an incident report or linking it to a massive power failure south of Jodhpur!

What tips would you give new pilots coming onto the Marut? 

“Watch your G when pulling out of dives on range or when turning at high speeds because she will do as you bid!”

What is the hardest manoeuvre to pull off in a Marut?

“Flying at the 300-ft AGL over the Rajasthan desert! Believe me it’s difficult! Stona grounded me for 2 full days while we were on detachment to Uttarlai. He spotted me at a much lower height and I had no choice but to tell him tongue-in-cheek that I found it too hard to maintain level flight at 300-ft. Many years later, when Stona visited our house in Austin, Texas, he recited the incident to my highschool-going daughters with mock indignation and feigned hurt.”

What should I have asked you?

“What was your biggest takeaway from the Marut flying experience? My answer would have been: God loves me! Flying Maruts, I realised low level strikes are a lot more fun than air combat. I just came to believe, hitting the adversary with bombs and rockets was a lot more fun than running around in circles with the adversary! I believe providence had a hand in my subsequent posting to Jaguars.”

Acknowledgements

I would like to thank Marut stalwarts Wg Cdr DK Cooper, Air Vice Marshal KP Sreekant, Wg Cdr KR Singh and Wg Cdr VS Kochar for their suggestions and review of my responses.

I served in the IAF for 20 years (1974 – 1994) flying the HF-24 Marut and the Jaguar. After taking premature retirement, I learnt software programming. In 1998 I took up a job in the US and stayed there till 2006 after which I resigned and returned to India.

I am a military technology enthusiast, particularly military aviation technology. I blog on Indian weapon system procurement and defence posture. I write for print and online publications. I am frequently quoted by the online and print media.

I have authored a fictional romance thriller set in the IAF.

 

— Vijainder K Thakur
Indian Defense Projects: https://sites.google.com/site/idpsentinel/ (Paid access)
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*(For clarity, I have used straight forward call signs. Not that I remember the actual callsigns of that day!)

 

 

 

 

2 comments

  1. Kawsika Basnayake

    Possibly the stupidest decision made by the Indian military was to stop the development of the Marut and follow on indigenous fighters. Now India is having “fun” operating a zoo of aircraft from all over the world and spending billions of taxpayer money on foreign entities. Dreams of becoming a superpower let alone a regional power are a pie dream without indigenous design capability…

    • Kartik

      Agree with that viewpoint. The HF-24 Marut needed a more powerful engine and commitment to develop it further and fix whatever issues the type had. Not abandon the entire effort altogether for the easier approach of taking Soviet fighters at friendship prices. The Marut could have had a follow on fighter as good as if not better than the MiG-23 and MiG-27 that were produced and inducted into the IAF in the hundreds. This short sighted decision making led to loss of most of the knowledge gained on the development of this type. But the lesson has been learnt and now India will never abandon an indigenous design just because it has some issues that need to be fixed. That is why we now have the LCA Tejas Mk1, Tejas Mk1A, Tejas Mk2 Medium Weight Fighter and the 5th gen AMCA program all being worked on.

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