Royal Air Force name: Tutor

TYPE: Aerobatic two-seat lightplane.

PROGRAMME: Developed from G 110 (first flown 6 February 1982) via G 112 (4 May 1984). First flight of Grob G 115 (D-EBGF) 15 November 1985; first flight of second prototype second quarter of 1986 with taller fin and rudder and relocated tailplane; LBA certification to FAR Pt 23 on 31 March 1987; British certification February 1988; FAA certification 21 December 1988; later gained full public transport certification and German spinning clearance; production terminated August 1990 after total of 103 (including prototypes) G 115/115As. Power plants and equipment updated and designations changed late 1992 for 1993 product line; total of 203 built by December 1999, comprising 103 early versions, one G 115T, 14 G 115TAs, single G 115B and 84 G 115C/Ds. Five for Royal Navy pilot training designated Heron.

CURRENT VERSIONS: G 115E: Selected in June 1998 for UK Ministry of Defence requirement to replace BAe Bulldogs in RAF University Air Squadrons (UAS) and Air Cadet Air Experience Flights, plus a squadron of the Central Flying School (CFS). Total of 99 ordered for operation at 13 sites in civil markings under contract managed by Vosper Thornycroft Aerospace (formerly Bombardier Defence Services). Development aircraft (D-ERAF) first flown early 1999; first production aircraft (D-EUKB/G-BYUA) and three others delivered to UK 15 July 1999; official handover of first five aircraft (G-BYUB/C/D/E/F) at RAF Cranwell, Lincolnshire, 13 September 1999, for CFS; deliveries to Cambridge UAS began 14 September 1999; final aircraft (G-BYYB) registered in August 2001.
Description applies to G 115E RAF version.
G 115EG: Version based on G 115E for the Egyptian Air Force, which ordered 74 in May 2000 for service at the Egyptian Air Force Academy at Bilbays 2 Air Bases. AEIO-360-B1B engine and MTV-12-B-C/C-183-17e propeller. First aircraft (D-EGYB/EAF 6801) formally handed over in Germany 9 October 2000; first batch of eight handed over by 1 December; deliveries continued at the rate of four per month until mid-2001, then eight per month until contract completion in February 2002. FAA certification 6 February 2001.

CUSTOMERS: By January 2002, production totalled 203 of early versions and 174 G 115E/EGs, or 377 in all, including prototypes and demonstrators, but excluding two G 110s and two G 112s. No further production by late 2003.

DESIGN FEATURES: Low-wing monoplane of composites construction optimised for flight training. Wing trailing-edge moderately swept forward; slightly tapered horizontal tail surfaces; sweptback fin. G 115E based on earlier G 115s, but with fuselage entirely of carbon fibre, saving more than 40 kg (88 lb) and thus allowing aerobatics to be performed at MTOW.
Wing section Eppler E696; dihedral 5°; incidence +2° at root, -2° at tip; tailplane section NACA 64010.

FLYING CONTROLS: Conventional and manual, via pushrods. Horn-balanced elevators with mechanically actuated trim tab in left unit; elevator deflection +34/-20°; mass-balanced ailerons with ground-adjustable trim tabs, aileron deflection +20° 25'/-18° 25'; horn-balanced rudder with ground adjustable tab, rudder deflection ±30°. Electrically actuated plain flaps, deflection 0, 15 and 60°; intermediate 45° setting optional.

STRUCTURE: Entirely of CFRP; semi-monocoque fuselage has rigid CFRP shell formed in two vertically split halves with frames and web members and integral fin; wing of CFRP/honeycomb sandwich with I-beam main spar and carbon fibre roving spar caps; CFRP/honeycomb horizontal tail surfaces of two-spar construction; rudder, ailerons and flaps are GFRP/rigid foam sandwich. Airframe is protected from lightning strike damage by means of aluminium fibres embedded in the outer layer of carbon fabric and copper mesh in the wing surfaces above and below the fuel tanks, all bonded to metal ground strips. Structural service life (aerobatic) 24,000 flight hours.

LANDING GEAR: Non-retractable tricycle type with GFRP wheel fairings; cantilever spring steel suspension on main units, gas damping on nose unit; mainwheel tyre size 6.00-6, nosewheel type size 5.00-5; nosewheel steering via rudder pedals, maximum deflection ±9° or ±47° with use of differential braking; hydraulic disc brakes.

POWER PLANT: One 134 kW (180 hp) Textron Lycoming AEIO-360-B1F/B flat-four driving Hoffman HO-V343K-V/183GY a three-blade, constant-speed (hydraulic), wood/composites propeller. Christen inverted oil system. Fuel in two integral wing tanks, combined capacity 150 litres (39.6 US gallons; 33.0 Imp gallons) of which 143 litres (37.8 US gallons; 31.5 Imp gallons) are usable, with collector tank, capacity 5.4 litres (1.4 US gallons; 1.2 Imp gallons) for up to three minutes' inverted flight; fuel filler port in top of each wing. Oil capacity 7.6 litres (2.0 US gallons; 1.7 Imp gallons).

ACCOMMODATION: Two seats side by side, under one-piece, rearward-sliding framed canopy; dual controls (sticks) standard; seats can accommodate backpack parachutes and have five-piece harnesses; baggage space behind seats. Cockpit is heated and ventilated.

SYSTEMS: Electrical system comprises 28 V DC 35 Ah engine-driven generator and 24 V high-capacity battery for engine starting and to provide 30 minutes' emergency power in the event of generator or main bus failure.

AVIONICS: Basic aircraft supplied without avionics. Optional minimum avionics pack includes Bendix/King KX 155A nav/com/glideslope, KI 203 VOR/LOC and KT 76A transponder. Typical customer-specified Bendix/King avionics fit for military trainer detailed below.
Comms: KTR 909 UHF selector with KFS 599A; dual KX 155A with KI 204 VOR/LOC/GS; KT 76A; KMA 28 audio panel; ELT; PTT switches on control columns and NATO-standard quick-release sockets for headsets.
Flight: KCS 55A compass with KG 102A slaved gyro unit; KI 525A HSI; KA 51B slaving control unit with KMT 112 magnetic azimuth transmitter; KN 63 DME with KDI 572 indicator; KG 102A slaved directional gyro; Filser LX500TR differential GPS.
Instrumentation: Standard ASI, VSI, turn and slip indicator, attitude gyro, directional gyro, tachometer, magnetic compass, CHT/fuel pressure gauge, manifold pressure/fuel flow gauge, oil pressure/temperature gauge, OAT/EGT gauge, fuel quantity gauge, voltage indicator, g meter and clock.

EQUIPMENT: Standard equipment includes navigation, anti-collision, landing and instrument panel lights; map light on flexible arm between seats optional.