FLYING THE SPITFIRE MK26B.
March 22nd 2007. Watts Bridge Queensland Australia.
Pilot, Richard Lea. Weight 87 kgs plus 8kg parachute. Campbell Aero Classics Helmet worn.80 liters fuel.
Weather, fine, 4/8 Cumulus. Base 3000, tops 5500. Wind 12 knots along dry (dusty) runway.
Cockpit was noticeably larger with more head and shoulder room. View through front quarter panels much improved in front of wing and along fuselage for taxi. The higher seating position also gives a more natural lean from the waist to view along the left side of fuselage when taxiing. Brakes very good, distinct improvement in feel and braking.
Aircraft acceleration rapid to 65 knots, tail lifted easily with no tendency to swing. There was no need to pull to get airborne and aircraft flown off at around 65 knots. Climb rate 2500 ft. /min at 85 knots with 4300 rpm and prop full fine.
Aircraft accelerated at 7500 ft. with fully course pitch to 168 knots. All temps and pressures fine.
Stalling. (Conducted with calibrated Instruments)
Aircraft stalled clean and with flaps and U/C down.
Nose dropped at 42 knots in landing configuration and 48 knots clean.
8 stalls completed all straight ahead. All easily recovered, max height loss 100-150 ft. Good feel in all control axis throughout these stalls. We have found with further testing that the stalls are neutral but wing drops can be induced if controls not central. Even with a slight wing drop it is fully recoverable almost immediately.
Spins. (Conducted with calibrated instruments)
Spins conducted, clean aircraft, one and a half turns each. Entry, full rear stick, throttle closed, full in spin rudder, ailerons central. A/cs nose dropped after 1/2 rotation. Spin slightly faster to right and tending to increase rate when starting recovery. Yaw stopped instantly when opposite rudder applied. Aircraft normal safe recovery, speed builds quickly after roll and yaw stops.
The Mk26b has excellent directional stability and steep 90 deg. turns at 3G with full throttle at 135 knots were flown left and right. Barrel rolls, wing overs and loops were conducted using a maximum of 4G and 160 knots at entry. The Mk26b was delightful to fly, with excellent visibility all round. The larger cockpit development of the Mk26b does not detract from the earlier MKs feeling of 'oneness' with the aircraft. The bigger wider bubble canopy gives ample headroom for the taller pilots up to 6ft 4inches with hard helmet fitted. The Mk26b is as agile as its smaller sibling and gives the pilot a much more comfortable environment to fly in.
Early flights are showing the Mk26b to be as docile and as stable in the landing phase as the Mk26 with the improved visibility outwards and downwards making the 3 point round out and landing even easier.
Circuit and Landing.
Mk26 speeds flown, full flap used. Approach, 70 knots, 65knots over threshold. Very good visibility over nose on finals with excellent height assessment to point of round out. Aircraft has no tendency to balloon up at round out and settles easily in 3 point attitude. Distinct improvement in vision compared to smaller Mk26.
The Mk26b is a welcome improvement in space and grace to the Supermarine stable. The bigger aircraft has lost none of its agility or excitement in handling. Indeed it has demonstrated a more directionally stable tendency with a more positive action with little over swing when centering the ball in hard maneuvers. The larger cockpit now easily accommodates two large adults making long distant flights even more comfortable and the improvement in visibility makes the Mk26b even easier to land and taxi.
FLYING THE SPITFIRE MK26.
The aircraft was fitted with a composite four blade fully variable pitch propeller without automatic constant speed control. A manual pitch selection switch on a panel on the upper left front console gave an 8 second adjustment range between fully coarse and fully fine. The Mk 26 has also been flown with a two bladed wooden propeller as fitted to the RV6 aircraft.
Some pilot seating and rudder control adjustments must be made prior to strapping in.
The aircraft is fitted with differential toe brakes on the rudder pedals. They are adjustable for length via panels either side of front lower fuselage. The front seat has three fore aft positions selected by removing two bolts on the seat frame. The rear seat has no adjustments with any stick or rudder controls fitted.
Walk round and Prestart Checks:
A positive check of the undercarriage locking levers, with their big black knobs fully forward on the front starboard cockpit wall, is advised before clambering under the aircraft. Combine this with a check of the 2 telltale locking pins protruding from the wings. More on the gear later. The aircraft has no fabric surfaces and only a couple of fiberglass fairings on the base of the fin attached by self-tapping screws. The aircraft is otherwise riveted aluminum.
The low wing requires a fair degree of bending and crawling around to check control rod connections, access panels, undersurfaces and undercarriage. The main engine panels on this prototype required 20 minutes to remove and replace (production models have redesigned panels) if a visually check of the engine is desired. Otherwise it is a simple task of checking quick release fasteners and 4 intakes for carby and cooling air.
A look up, for oil leaks, in the lower engine sump area, can be achieved if the engine cooling cowl, which hinges down immediately in front of the firewall, is fully opened on the initial cockpit check. This push /pull control is handily placed at the lower front console.
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