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How the Gnat Benefited Indian Industry

By Gp Capt Kapil Bhargava (Retd)

Acquisition of the Gnat by IAF resulted in a number of benefits. It not only got our fighter pilots a fantastic Sabre Slayer, it also gave the aviation industry many other associated benefits. We will look at what the airframe side did for us a little later as we try and build up the authentic history of the Gnat. In my opinion an aircraft designer needs to consider the engine as soon as he thinks of creating a new aircraft,if not sooner. An aircraft project will go nowhere unless an engine matching the designer’s aspirations is either already available or is about to arrive on the scene.

The engine selected by Ted Petter for the Midge was the Saturn being developed by Bristol Aero Engines Ltd. But the project was aborted after the British Government decided against it. Petter had to use the Viper which powered the Jet Provost.
Fortunately for Petter, even this lower power engine on the Midge gave it very nippy performance, including supersonic dives. This proved that his concept of the Gnat as a light (Low Cost Aircraft = LCA!) fighter was viable. Coincidentally, the Orpheus engine appeared on the scene exactly at the time it was needed for the Gnat. The aircraft was designed to intercept incoming attackers before they crossed the English Channel. After the British Government rejected the Gnat, even more fortunately for Petter, we bought the aircraft. With it came the Orpheus to India to be produced under license in the country.

Contrary to much of our R&D efforts, I do not believe copying a product really helps us. The industry neither learns how to design such an item nor gets the production technology to do a proper job at the correct price. My thesis was and still is that we should take a licensed item and develop it to the next level. This is what the Japanese did, starting with textile machinery from Manchester. We have done this in a very limited way.

Let us now list the applications to which the Orpheus was applied. First of all, it helped create an Engine Division within HAL. Apart from its use on the Gnat, the same engine powered the HF-24 and the Marut Trainer. Its de-rated version is still in use on Kiran Mk II. A re-heated version, so-called developed by GTRE was used to power the HF-24 Mk IA, IBX and IR. But its most daring application was on the C-119G Fairchild Packet. The best person to describe it is Group Captain Jacob Chakko, the brains and the working hand almost solely responsible for the success of the project.

Orpheus Jet Pack on the Packet
By Gp Capt Jacob Chakko Tech (Eng)

Fitting Orpheus Engine Jet Pack on the C119-G was indeed very interesting. It was a challenge at ‘that’ time to suggest that the Orpheus could be used as a Jet Pack because there were too many ‘nay-saying wet blankets’ who had doubts whether that engine could also run on the 115-Octane fuel used by the Packets.

So here is a short summary of the Orpheus installation and a little of what was involved, engine-wise. Yes, my technical paper had riled a lot of people in high places. But once AVM Pinto and the CAS Air Mshl Aspy Engineer had okayed it as an Operational Requirement, and AVM Ranjan Dutt at HAL was given the task, I had quite a lot of support for its quick ‘denouement’.

Orpheus to run on Packet’s High Octane Fuel.
The IAF Orpheus Engine was only cleared to run on JP-4 for us. For the Jet Pack we had to clear it for use with the Packet’s 115 Octane fuel. Special tests were run at the Engine Factory for 400 hours plus. The engine was inspected every 100 hours or so. There was a micro-thin greenish-yellow coating of a ‘lead oxide deposit’ on the hot parts from the combustion of the High Octane Fuel. But it was decided that the engine’s performance was not affected in any way. So the TBO for the Orpheus Engine was retained at the normal at 400 hours (as I recall) on this installation.

Orpheus Fuel Pump Life
However, since the Fuel pump was also running on this high octane fuel which had less lubricity than JP-4 kerosene, it was decided that the fuel pump would be mandatorily inspected and changed at 200 hours. I believe this figure was later changed to 250 hours. My memory fails me a bit now. (He is 84 now- KB).

Orpheus on a Hydraulic Starter
The Orpheus at that time could only be started with compressed air from those massive high pressure cylinders on the ground. These cylinders weighed a whopping 1750 pounds each. These Packet aircraft had to land and take off from airfields where such facilities were not always available. It was therefore decided that 2 such cylinders would be installed in the Packet’s Aux Deck to give the aircraft total independence from ground equipment. The Orpheus could be started in the air by wind-milling it but it became an IAF requirement that the jet had to be running at take-off also. Missing this installation would have meant a reduction of nearly 3500 – 4000 pounds in payload capacity. An alternative Engine starting system had to be found asap!

The ‘designers’ went on a rampage for a few months to find an alternative electric or hydraulic starter from the international market. A suggestion that the extant Hydraulic Starter on the Westinghouse J-34 Jet Engine would do the trick was rudely ridiculed. Discussions were held ‘in camera’ with Air Cdre S Rikh of the Engine Factory who, being convinced that this could be done, took it on himself to produce the very simple modifications. Having been done (hubba hubba) and having proved itself totally successful in the Engine Test Bed, Air Cdre Rikh called AVM Ranjan Dutt and requested him to come and start the Orpheus with the Hydraulic Starter by himself. Having satisfied himself that this was a successful mod, the AVM called the CAS from the Test Cell itself and said to him,”Sir, we at HAL do the impossible, miracles take a little longer”! This was ‘a la AVM Harjinder Singh’ for those who know the allusion!

The Pay-Off
The result of this modification was immediately felt by the Packet Aircrew who straight away had an extra 3 – 4 thousand pounds extra in payload carrying capacity. And the increased factor of safety in flying in Ladakh will always be remembered also by a single episode where ” Air Marshal PL Purohit and Winco HB Singh flew a Packet on the Orpheus Jet alone, with both piston engines feathered, from Zojila to Srinagar, a distance of over 100 miles, losing height in a powered glide from 18,000 feet and maintaining level flight at approx 7,500 feet over Srinagar.

Net Results.
I am told these modifications of the Orpheus Jet Pack not only extended the Service Life of the Packet C-119G aircraft by 20 odd years, from 1964 to 1984, but also gave HAL a whopping order for over 150 Orpheus Engines plus oodles of work in overhauling Packets and the Jet Engines over the years.

I hope this is useful information.

My Life With The Gnat

By Air Marshal R Ramamurthy (Retd) PVSM VSM

Since April 1963, I was an Instructor in Air Force Technical College. I got married in November 1964. As a Flt Lt, I was deputed for a Hunter aircraft MCF course in Halwara, in January 1965. While I was in Halwara- one day- I got a call from Ambala ” You are posted to 15 Squadron, with rank”. I knew that 15 Sqn had just then been reequipped with Gnat aircraft. I did’nt have to break the news to my wife- she had already got it from the Ladies club network. Those were the days when we needed no cell phones!

After a couple of days, I got another call from Ambala. This time, it was the CO of 15 Sqn, Wg Cdr MJ Dotiwala (Later Air Marshal)- ” Come and join Immediately- we need the senior technical officer badly”. I told him that I had to go back to AFTC, clear and then come.

In March1965, when I reached Ambala Cant railway station, I found a number of airmen frantically loading a special train. I was told that No 2 & 15 Sqns were moving to 15 Wing in Bareilly. Since my belongings were already on the railway platform, I got them loaded in the special train- keeping with me only essential things!

I reported to the CO and was told that we were moving to Bareilly in a week’s time. We had not heard of Bareilly earlier. I got busy reading the manuals and getting acquainted with the aircraft.My two years stint in AFTC as an Instructor and my earlier thee years as EO in No 1 Sqn (Mysteres) helped me in getting to know the aircraft faster. A weeks time is not sufficient for getting to know the aircraft nor the other officers nor the technicians! However, in those few days in Ambala, I had established close relationship with my CO- Wg Cdr Dotiwala and the flight commanders- Sqn Ldrs Upkar Singh
and ML Chaturvedi- which has continued till now- growing stronger over the years! I had a young technical officer with me- Plt Offr SR Bendre, who gave me tremendous support.

On the designated day, all the aircraft of 15 Sqn flew into Bareilly. None was left behind. This was an achievement by itself.I reached Bareilly in the staging aircraft. No 2 & 15 were the first squadrons to operate from the newly established 15 wing. We maintained 75% serviceability. Earlier it was said that Gnats cannot operate from any base other than Ambala!

We had a bunch of young pilots in the squadron. the whole squadron functioned as a closeknit family!
Our “Chiefy” in the sqn DSS was Flt Sgt Irani- a tall and well built person. He had excellent control over the airmen. They were scared of him, but at the same time adored and loved him. He will line up the aircraft by 0630 hrs and the first sortie of 12 aircraft will get airborne by 0700 hrs!

The work in the RSS was well planned. We had a good set of experienced and dedicated technicians. One thing with the Gnat. For any rectification we had to pull out the rear fuselage and drop the engine, to get access. But these operations were easy and comfortable.After servicing when we sent an aircraft for airtest, it will invariably have a PRL flameout, at altitude. The altitude at which this occured gave us a clue to do correct adjustments! The drill was to run up the ATC tower after seeing off the aircraft, to monitor when the flameout occurred and also be ready for any emergency. The relight after descending to 15000 ft was always successful.

We went thro the alert which was sounded when the Kutch operations took place. From then on we were standing by for operations. In Sep1965- one night- at about 0430 hrs- we heard the drone of Packet aircraft circling over Bareilly airfield. we rushed to the airfield. They landed at daybreak. The Packet squadron has been despatched from Srinagar. Operations had started. No2 Sqn and half of 15Sqn aircraft moved to Ambala. The other half of 15 Sqn aircraft and pilots & technicians moved to Agra- leaving behind the Packets in Bareilly.We kept a team of technicians in Bareilly for serving of the Gnats, as and when required. I was mainly in Agra. In Agra, the squadron mounted CAP sorties continuously from dawn to dusk. On one such pre-dawn sortie Sqn Ldr Chaturvedi swerved during take-off and hit the runway lights. He abandoned take-off. The aircraft was a total write off but Chato escaped with a fracture of the leg. We had to send an aircraft back to Bareilly for inspection. I estimated that the inspection will take 3 days- normally it would have taken 8 days. My “Chiefy” in the R&SS called me up the very next day and said that the aircraft was ready. They had been working on it continuously for 24 hrs!

For giving a max throttle ground run of Gnat aircraft we had to use chocks which were lashed.Without these chocks the aircraft would move forward even with brakes on. We did not have these lashing chocks in Agra. They had been sent with the Ambala detachment. We had an aircraft which had to be given a max throttle ground run. I had therefore requested one of the young pilots to taxy the aircraft to the end of the runway and give the ground run.He was thoroughly briefed by me and the flight commander that the aircraft will move but he is not to release the brakes. However, to our horror, we noticed that he released the brakes, picked up speed and then braked. He did this not just once but thrice. The aircraft whizzed past us on the other end of the runway and crashed in the overrun area.The brakes had got heated up and hence the aircraft could not be stopped. The aircraft was a total write off- fortunately the pilot was safe and unhurt.

We came back to Bareilly after the cease-fire was announced.We had a change of CO. Wg Cdr CV Gole (later Air Marshal) took over. Bhayya Jatar took over as senior flight Commander. The squadron was training hard. The cohesiveness was built up further.It was indeed a great time. 24 Sqn was formed with Wg Cdr MM Singh (Later Air Marshal ) as CO.Now we had three Gnat Squadrons in Bareilly. Earlier it used to be said that Gnats could operate only from Ambala and nowhere else.
We went for the Republic day flypast. We operated from Palam. On every rehersal day 18 Gnats will get airborne for the flypast and land back safely.We maintained 100% serviceability throughout the period. On posting out of the Chief Engineering officer, Sqn Ldr IG Krishna (Later Air Marshal), I took over as CEO 15 Wing. Sqn Ldr IG Krishna was the pioneer of the Gnat and had established a name for himself. He was no doubt an outstanding engineer.

15 squadron moved to Jamnagar for “Air to Air firing”. The results were excellent. One day, in Jamnagar, an aircraft taxied out with an air intake blank still on, on one side. The manual advised a change of engine. I was summoned from Bareilly. I inspected the engine thoroughly and since there was no damage at all, I cleared it for further flying. I was in Bareilly till April 1967. I was sent to USSR for training on Su-7 aircraft. I loved the Gnat and was amazed at its design features and
superb performance. At the same time, maintaining the aircraft was a challenge and a great experience. One had to be alert all the time.

My experience on the Gnat stood me in good stead throughout my career.

Ready for action – GNAT Mk 1 – E1038

By Wg Cdr (Retd) Prakash S Sanadi

Gnat aircraft E-1038 was on AOG for over six months. Its parts had been cannibalised to recover other aircraft, with the result it had to be kept propped up on three picketing blocks in a blast pen in Ambala, minus the undercarriage, engine, canopy, ejection seat etc. The blast pen had not been used in ages and had a lot of bushes and junk material lying in it. E-1038 was looking like a junked aircraft forlornly kept in a corner with dust covering its airframe and a piece of canvas just as dirty and torn, haphazardly spread over the cockpit.

15th Dec ’71. With the Indo Pak Dec ‘71 war at its peak Ms Hindustan Aeronautics Limited was tasked by Air Hq., with immediate supply of items on AOG for all aircraft of HAL manufacture in the Western Sector. Chairman HAL ordered all concerned Divisions to immediately arrange to supply all the AOGs items and airlift the required items in the HAL Avro. A message to this effect was flashed to Hq WAC who in turn informed C Eng O, Ambala that the Avro would arrive on 17th Dec 71 with all the AOG items for E-1038 and the aircraft has to be kept ready for rebuild which is to be completed within 24 hours and the aircraft be flown out to Amritsar for operational duties. Flt Lt Sanadi was tasked by Wg Cdr Johnny Greene, OC 2 Squadron AF, to monitor the progress and when the aircraft was ready, he was to air test the aircraft on a flight towards Amritsar and land there only.

16th Dec ’71. Never had a squadron achieved what transpired in the next 24 hours. The STO of No 2 Squadron, Sqn Ldr Shaukat Ali ordered all the available manpower to start cleaning the blast pen and the aircraft, camouflage the blast pen completely so no light could be visible from the outside. The activity was feverish, the blast pen was cleaned of all the bushes, the aircraft was washed with soap water and wiped clean, the cockpit was vacuum cleaned. The blast pen was camouflaged and fitted with flood lights focused on the aircraft, all equipment required to work on the aircraft was positioned in the blast pen procured from the R & SS and each team was tasked to complete their responsibilities in the shortest possible time. Meals, tea, coffee etc were arranged to be delivered by the Mess in the blast pen. Sleeping arrangements (in fits & starts) were arranged in nearby rooms with attached toilets for all personnel working on the aircraft.

17th Dec ’71. The HAL Avro aircraft landed at Ambala at about 1pm. All the equipment required to rebuild E-1038 packed in neat boxes was off loaded and moved directly to the blast pen, where it was opened and segregated. The engine & ejection seat complete were positioned on their trolleys side by side in the blast pen. At about 4pm the work to rebuild E-1038 commenced. It was getting dark and the weather was biting cold with a stiff cold breeze blowing to make matters worse. At about 10pm Flt Sgt Ramamurthy an engine tradesman came to Flt Lt Sanadi and requested issue of two bottles of Rum. Sanadi was dumbfounded with the request, but Sqn Ldr Shaukat Ali was there to reassure Sanadi and said give it to him. So two bottles of Rum were issued!! Sanadi then went to monitor the progress. Cpl Yadav leaning his back to the main wheel as a support was seen desperately trying to lock the buttons of the rubberised wing fuel tank inside the wing. This task was done just by feel through a opening on the under surface of the wing. His hand and back paining he continued with his task. Sanadi offered to help and was able to push just one button into its locking slot before his back & arm gave way. Yadav laughed and took over the task himself. The blast pen by now was a beehive of activity, AOC Ambala with the C Eng O came to see the effort being put in. Sqn Ldr Shaukat Ali was asked when the aircraft would be ready for the test flight and he said the plan was to have the aircraft ready for the ground run at 9am the following morning, the time at that moment was 2230 hrs. Sanadi was told to return home and get some sleep and be ready for the air test the following morning. Simultaneously the air raid siren went off but the technicians continued to work on the aircraft, unmindful of the risk they were taking. They appeared like ants clambering all over the aircraft in their effort to complete the task in hand.

18th Dec ’71 0900 hrs. E-1038 a gleaming Gnat in all its splendor was towed out of the blast pen and positioned for the ground run just out side the blast pen. A bowser was positioned to top up the aircraft after the engine run. The engine tradesman was inside the cockpit all set to start the engine. At the given signal the engine was started up with the sound of a beautiful whine of the engine RPM winding up. Everyone assembled gave a loud cheer and a thumbs up signal. The ground run was successful and no snags were encountered. Slight adjustments were made and the engine was switched off. E-1038 was readied for the air test & ferry. ATC got the clearance from ADC for the air test & ferry of the aircraft to Amritsar. Sanadi got into the cockpit, quickly strapped himself in, closed & locked the canopy and gave the signal for start up. Checking all the parameters, he asked for taxying out and line up permission from the ATC. Again there was a roar & clapping from the crowd of tired officers, technicians and NCE’s as the aircraft was taxied out. Everyone saluted and E1038 rolled out and lined up for take off. ATC controller called 35 GOOD LUCK, YOU ARE CLAEARED FOR TAKE 0FF. With a full throated roar of the engine, E-1038 was airborne and zoomed off into a brilliant blue sky, climbing away. With radar cover provided, Sanadi checked out the aircraft enroute to Amritsar, informed Ambala operations normal landing at destination. At approximately 1120hrs E-1038 landed at Amritsar airfield and was inducted into operational flying. A job well done by all the personnel & M/s HAL. E-1038 remained fully serviceable through out the war.

A hair-raising incident with Gnats

By Wg Cdr Prakash S Sanadi

3rd DECEMBER 1971

The IAF had called off Operation Cactus Lily in the Western Sector with the defeat and surrender of East Pakistan. No. 45 Sqn (MiGs) were ordered to pack up from Amritsar and move back to Chandigarh as the war in the East was over. A detachment of No 2 Squadron (Gnats), on ORP and Operational duties, also operating from Amritsar, was asked to wind up and return to Ambala.

Area of Interest - Ambala

Sandy (Flt Lt PS Sanadi) was in Ambala waiting to ferry a Gnat aircraft under engine change to Amritsar. He was instructed to report immediately to Amritsar by Wg Cdr JW Greene Commanding Officer of No 2 Squadron to help in the winding up of 2 Sqn detachment. Sandy was planning to leave Ambala by train the same evening when he got a call from Mrs Greene to say she would be accompanying him as the war scenario in the western sector was over and her visit to Amritsar was agreed to by her husband. Geeta, Sandy’s wife also decided to join in the joy ride to Amritsar. So the train journey was cancelled and Sandy decided to drive down to Amritsar in his Fiat car.

Continue reading A hair-raising incident with Gnats

Register – Online or Offline

People have been writing in asking for a form that could be printed out, filled up and sent forward to the committee organising the event.  This is essentially to assist those without online access. Of course, those with access will still have to download, print and pass on the forms but its an easy enough process.

For those who want to register for the event online, the page has been open for a quite a few days now and registrations are literally pouring in. Click here to go the registration form online.

Forms to print are available both as a MS-Word document as well as a PDF document.

Printed forms need to be mailed to:

Gp Capt NK Krishnan (Retd),
Chief Manager (Flight Operations & Safety),
Corporate Office,
Hindustan Aeronautics Limited,
5/1 Cubbon Road, Bangalore – 560 001

Do register as soon as you can.

Auditors & Their Ilk

Wg Cdr CK Sharma (Retd)

If aircraft behaved, auditors were ready to help cause trouble

Sometime in the mid-sixties, auditors visited the Gnat Sqn I was in. And, soon enough, they found that two aircraft had both been refuelled after their sorties with the same amount of fuel and yet, the Autho Book as well as the F700 showed that one aircraft had done 50 minutes’ sortie whilst the other had done a 30 minutes’ sortie. This, they insisted, was a case of certain defalcation as both the aircraft had got airborne within minutes of each other.

After the initial flutter, the Flt Cdr realised what had happened: one had gone for a Hi Level Nav sortie whilst the other was on a Lo Level Nav! And yet, it took all of three hours of explanation to tell them that the rate of fuel consumption would be different at different altitudes!

Why IAF went for the Gnat?

By Group Captain Kapil Bhargava (Retd)

In early 1954, Indian Air Force defined its Operational Requirements (OR) anticipating that its adversaries would most likely be China and Pakistan. Intelligence information with Air HQ identified the probability of Pakistan being supplied with fighter aircraft from the US, China and Russia. India would need not only to procure aircraft to meet any threat, but also ensure that long-term air defence needs would be met by large-scale design and manufacture in India.

An elite team was picked to study, test and recommend new aircraft and weapons systems that would fulfil the operational requirements of the next 10-15 years. The team was headed by Air Cdre PC Lal, with members Gp Capt H Moolgavkar, Squadron Leaders Roshan Lal Suri (test pilot), Suranjan Das (test pilot), Srinivasan (Sigs), UK Nair (Armt), K Sarwate (Elec) and Fit. Lt. Jacob Chakko (Tech Eng).

Following IAF’s purchase of hundreds of Ouragans from France, world markets realised that India was a big buyer. She had the necessary foreign exchange reserves, and would not allow her Independence to be compromised by letting the big powers to dictate to her. European countries by then had a healthy respect for the Indian point of view as put out by PM Nehru. All of a sudden, everyone wanted to sell aircraft, guns, ships, tanks and a whole heap of military hardware to India. After all, such sales would boost their own countries’ economic well-being.
Continue reading Why IAF went for the Gnat?

50 years of the Gnat

On Friday 21 November, 2008 Hindustan Aeronautics Limited (HAL), will be holding a nostalgic celebration for the Golden Jubilee of arrival of the Gnat in Bangalore.

It will begin with a session at HAL’s Dr Ghatage Convention Centre where hopefully some old timers will talk about the aircraft. This will be followed by a lunch hosted by HAL.

In the evening there will be a dinner for guests with wives by invitation.

All pilots and engineers involved with the Gnat in IAF, its manufacture in HAL or designing of Ajeet, would be welcome. If you are willing and able to attend, please plan accordingly. Please also spread the word around, especially to those who do not use computers.

HAL has expressed its inability to help with travel, accommodation or transport. If you wish to attend, please come back to this site in a few days where you can fill up the form for joining the celebrations. You may also need to help with the registration of friends who do not use computers.