Flight Impressions- Grob 115

It was with great interest therefore that I accepted an invitation from Flight Safety Products Australia to sample a recently introduced trainer from Germany, the Grob G 115. The interest centred around both the fact that this is a European type and also that it is manufactured entirely of Glass Reinforced Plastics (GRP) and is in fact the first such aeroplane to be so manufactured to achieve FAA Certification and go into full production.

Considering Burkhart Grob Flugzeugbau’s background, it is not surprising that the G 115 should be built of GRP. Formed in 1972, it has made its name building some 3,000 aircraft from this material, most of them motor gliders and sailplanes. The G 115 is actually Grob’s third attempt at a two seat trainer made from GRP. The first, the G 110, flew in 1982 and achieved very limited production, the G 112 followed two years later but never progressed beyond the prototype stage and the G 115 represents the culmination of that effort.

The prototype first flew in November 1985 and four models are now available, the basic G 115A with 115hp Lycoming O-235-H engine and fixed-pitch propeller, the G 1158 (160hp Lycoming O-320-D and FP prop), G 115C (as the ‘B’ but with a constant speed propeller) and the G 115 Sport Aero which has a 180hp LyO’oming AEIO-360-B complete with inverted fuel and oil systems, constant speed propeller, stick rather than wheel controls and a fully aerobatic +6g/-3g structure. The lower powered G 115s arestressed to a ‘semi-aerobatic’ +4. 4g/-1. 76g and are approved for unlimited spinning overseas. At the time of our test, Australian approval had not yet been awarded but was imminent. Flight Safety’s Chris Higgins showed me around the subject of this flight, G 115A VH-TGV (locally dubbed the ‘T -Bird) on my arrival at Sydney’s Bankstown Airport. Obvious first impressions included the high quality and smooth finish afforded by the GRP construction and the sliding cockpit canopy which affords much better visibility than the average American ‘spam can’.

Preflighting the Grob is in the main simple – an exception is checking the pitot tube which is mounted on the top of the fin – and visual inspection of fuel quantity (the tank is mounted behind the seats) is afforded by provision of a clear viewing panel. Clear panels are also provided under the wings for inspection on the control bell cranks.

Entry to the Grob is easy, the canopy slides comfortably (both from outside and in) and the cockpit has an air of quality about it enhanced by the very comfortable seats and the saddle stitched genuine leather instrument panel surround. Once installed in the Grob, a problem resulting from my very tall (6ft 4in/1. 93m) frame immediately arose. Much of my extra height is in my legs, and these were jammed hard against the underside of the instrument panel, making operation of the toe brakes very difficult. Interestingly, Chris Higgins, who is only an inch shorter than me, has no such problem. Obviously his height is in his torso, but the problem remained with me throughout the flight and I was never comfortable with it and in fact got a cramp in one foot as a result. Chris had to operate the brakes for me on landing. This would affect very few people, however, and almost everyone else would find the fixed seat/adjustable rudder pedals arrangement more than adequate.

The instrument panel follows standard practice with flight instruments on the left, radios in the centre (Becker units in the case of TGV with facility for several preset frequencies) and engine instruments on the right. The switch for the simple electric flaps is immediately above the centre console with its indicator below it but offset to the right. Behind that are the well placed throttle and mixture controls and then the elevator trim wheel. A nice feature is the simple parking brake lever in front of the pilot which just slides a couple of inches left or right to put the brake on or off.

Engine start is in the traditional Lycoming manner, although those used to types with a direct connection between the rudder pedals and the nosewheel for steering on the ground will have to get used to the bungee system used on the Grob, which is similar to that on the Grumman American range. A few swoops to the left ,and right of the taxi line while I got that sorted out followed brakes release from the starting point but within a short distance I had learned to anticipate the aircraft and managed to taxi it in a straight line. My cramped legs weren’t helping either!

Engine run up is conventional Lycoming and the other post takeoff checks are much like any other single engined light aircraft. The takeoff was easy, requiring very little anti-torque rudder and the aircraft flew itself off at just under 60KIAS. I thought acceleration was a little leisurely until I remembered we were close to maximum weight, the outside air temperature was ISA+15 and we only had 115hp dragging us along. Once airborne, the Grob climbed well and the initial rate at best climb speed (70KIAS) of 750ft/min was well above the book figure. Immediate impressions once airborne included a good solid feel. Cabin noise is reported as being slightly better than average, although as we used headphones on this flight this was not tested.

Some general flying around Bankstown’s training area followed and the impression of well balanced and responsive controls immediately took over as we tried turns of various steepness in level, climbing and descending flight plus a gliding descent. In fact the Grob’s handling cries out for a stick control column rather than a wheel, although apparently the professional flying schools who are turning out the airline pilots of the future prefer the latter. Roll response was particularly good – perhaps even a touch too light for a student – and is one of those characteristics which seems to contribute to the European rather than American ‘feel’. The Grob has alloy control rods instead of the usual cables (which can stretch) and these would contribute to the aircraft’s control feel.

Visibility was at all times excellent, the clear panels in the top of the canopy helping create a sense of visual security in Bankstown’s congested training area.

Stalls were easily dealt with providing the ball was firmly in the centre. If not, a wing tended to drop although this was countered simply by using rudder. This characteristic is not necessarily a bad thing though, as it teaches students the correct way of dealing with such a situation. In fact the overall impression of the Grob was that it is a good trainer because it is easy to fly adequately and is forgiving enough for a student, but requires a little more effort to fly really well. Having said that, while reflecting on the flight afterwards it came to me that I was required to do very little retrimming in the aircraft, even upon application of flaps.

Getting a student into the habit of thinking out his trim and adjusting where necessary is surely a good the Grob’s single fuel tank obviates the need to get into the habit of switching tanks when appropriate but this is a fact of life in several similarly designed trainers.

After about an hour of playing with the Grob and (apart from the foot cramp) enjoying every minute of it, it was time to return to Bankstown. The first of two landings turned into something of an adventure, not because of the Grob but a Citabria pilot who displayed poor airmanship. A straight in approach to Bankstown’s Runway 11 was approved, and upon calling “Warwick Farm” (about three miles out) the Citabria pilot made a similar call within seconds of our’s. This indicated he was very close to us but we could not see him above, behind or adjacent to us. Our only blind spot was immediately below so we had to assume he was there and reduced our rate of descent accordingly. Consultations with the tower over the next minute or so indicated he was not where he had reported and we continued the approach even though we were higher than desirable on mid finals. With full flap (40 deg) applied and power cut, the Grob responded to the need to lose height quickly and was put down not far past what would have been our original touchdown point. As it turned out, the Citabria was some five miles behind us when he reported as being in the same place, and his actions caused us a few concerned seconds as we tried to find him.

I performed a single circuit and a less demanding approach and landing to conclude my flight in the Grob, although the crosswind and my by now almost numb legs and feet did combine to ensure I touched down with a little bit of drift which was easily absorbed by the rugged steel spring undercarriage.

All in all, a nice aeroplane which has an air of quality about it. If only they’d provide one more notch of rudder pedal adjustment