Air Marshal Philip Rajkunar (Retd)
After the first few flights of the first prototype the project was
languishing for want of clear directions from Air Hq. AM Katre revived the
project when he was Chairman HAL from 1981-84 and gave a clear directive to
the Design Bureau to complete the flight test program.
I was Chief Test Pilot at ASTE from Sep 84 to Aug 88 and was lucky to do
some prototype testing on the trainer version. Only two examples were built
and both were not to the same Standard of Preparation (SOP). The aircraft was
heavier than the fighter version and we had to have 150 knots over the
threshold to effect a smooth touch down. With such a lot of kinetic energy to
dissipate, we had to work the brakes really hard to turn off at the end of
the 10000 foot runway at Bangalore!
The aircraft was put through a limited high Alpha and spin programme. I did one spin test with Wg Cdr P Ashoka, CTP HAL, in the front seat. We climbed to
40000 ft to enter the spin. Entry was standard, in that we slowed down to
about 100 knots and applied full rudder in the direction of the intended
spin and brought the the stick fully back while simultaneously throttling
back to idle. The aircraft did not enter a classic spin but gyrated wildly
about all three axes and lost a great deal of height in the process. The
Flight Test Engineers at the telemetry station kept a watchful eye on the
JPT as it had a tendency to cross limits due to unstable airflow thruugh the
engine. We were prepared for a flame out but that did not happen. The test
called for holding pro-spin controls for 20 seconds and by the time we
initiated recovery we had descended below 30000ft in a steep nose down
attitude. Recovery was prompt once controls were centralised and we finally
levelled off at 20000ft. We repeated this three times in that sortie and
never succeeded in entering a conventional spin.
I also flew two sorties at night with late Ashok Yadav trying to assess
visibility from the rear cockpit during the approach and landing phase. The
rear cockpit had a periscope with a very limited field of view and was
useful only to line up with the flare path. Flare out and touchdown had to be
done by craning one’s neck to the left to catch a glimpse of the lights to
judge height. The landing lights were not too good and because of the high
touch down speed and not so good brakes it was not a pleasant experience.
On the whole the Ajeet Trainer gave valuable design experience to the Design
Bureau and to that extent it was worth the effort. The product, however, was
not a pilot’s aircraft.
The spin characteristics of the Gnat fighter were relatively straightforward especially for a swept wing aircraft of relatively early design. According to Folland’s Chief Test Pilot A.E. Ted Tennant, “With the possibility of the Gnat trainer going into R.A.F.
service, spinning characteristics need careful checking. Preliminary
work has revealed no vices in spins up to three turns in both
directions” (from http://www.flightglobal.com/pdfarchive/view/1957/1957%20-%201711.html)
This article from Flight has interesting snippet on the Gnat trainer spin models (http://www.flightglobal.com/pdfarchive/view/1963/1963%20-%201360.html)
The Gnat trainer (in effect a different aircraft) was “and
be cleared for two to three turns of a spin each way with droptanks
in place” (according to http://www.flightglobal.com/pdfarchive/view/1959/1959%20-%203173.html)
The last line is telling . “The product,however, was
not a pilot’s aircraft. ”
Most probably this answers the poser by Wg Cdr Thomas as to why Ajeet Trainer was not selected as an AJT .
PM Velankar , Velu
The above answers some of Wingco Thomas’s question about why the Ajeet trainer was not chosen as the AJT.
High landing speeds with the flaperons and the high workload for a relatively low time student would not make the Ajeet an easy step up for a Kiran/Iskra pilot. Add to that the cockpit size restrictions on the pupils – and the MiG-21U doesn’t seem that bad for an AJT. After all the Soviets used the MiG-21U as an AJT (after some 200 hrs on the L-39).
The Folland Gnat trainer is a case in point – it had to be extensively modified for the RAF to accept it and it was a Gnat in name only. New thinner larger area wing, with outboard ailerons and flaps, datum trimming, q-feel for the elevator, automated reversion to manual and a host of other modifications needed to be carried out. And despite all that, it couldn’t carry armament and Hunters had to be kept around to make sure even the smaller tall guys could train to fly fighters. http://www.flightglobal.com/pdfarchive/view/1959/1959%20-%203173.html is in interesting read about the Gnat trainer.
Dear Air Mshl,
It is true of the gnat that it takes great effort to get into a spin.I recall my 1 Vs 1 sorties from position of no adv,i.e abreast at 1500 to 2000yds.After the initial turn in,if conditions were not right for a reversal and scissors,one of us was generally in an incipient spin condition with rudder deflected,stick to the same side and mild and continuous judder,speed 180 kts or so.The combat would continue till the briefed height was reached and controls relaxed.While many may debate the complexity of flying the Gnat,to be honest,she did allow you, a fair amount of unskilled handling.I would appreciate comments on this.