In designing the Pilis,
Ernő Rubik was influenced by the arrival in Hungary of a
German Göppingen Gö 1 advanced trainer, itself a response to the
Grunau Baby. The Pilis emerged as a smaller development of his
Szittya. The prototype (R-08a) and first production model (R-08b) of the Pilis had
gull wings but later versions had wings without
dihedral. All were mounted on top of the fuselage and had a single
spar with
plywood covering forward of it around the
leading edge, forming a torsion resistant D-box. An internal drag
strut ran from the inboard spar to the fuselage and the area ahead of this spar was also ply covered. The rest of the wing was
fabric covered. The inner part of the wing plan was rectangular but the outer panels tapered to rounded tips. Long span
ailerons were mounted at an angle to the main spar and had constant
chord over most of their length but tapered on reaching the inner part. The first two production variants, like the prototype, had no
airbrakes but these were introduced on the R-08d, initially designated
R-09, mounted on the rear of the spar between the tapered section and the drag strut. The Pilis's fuselage was a ply semi-
monocoque structure with strengthening
frames and
stringers, roughly oval in section but with sharp junctions above and below. The forward part, with the wing on its top and open cockpit below and immediately ahead of the
leading edge, was deepest before tapering to the tail. Overall, the fuselage of the prototype appeared to be slightly curved in profile but correction of control problems in
landing flare led to a straightened fuselage, lengthened by , for all production variants. All production models had similar tails, with tapered and round-tipped horizontal surfaces mounted just above the fuselage, to which the
tailplane was braced with a single strut on each side. Tailplane and
elevators had roughly equal areas. The
rudder was full, curved and mounted on a very small
fin. The tail of the first prototype, the R-08a was a little different from those of production aircraft, with a taller fin,
unbalanced rudder and a noticeably taller tailplane pylon. All Pilis had a standard rubber-sprung landing skid under the forward fuselage. On most this ran from the nose almost to the wing
trailing edge but some later R-08ds and
B-2s (a new name for R-08ds built in a production run started in 1956) had a shorter skid, which ended below the bottom of the wing strut, with a semi-exposed monowheel just aft of it. The same late series introduced enclosed cockpits; all earlier models had a removable ply cockpit surround, of model-dependent size, fitted with a simple windscreen which left the pilot's head and shoulders exposed but on these late examples the screen was replaced with an enclosing transparency. One B-2, the
Győr 3 Motor-Pilis, was motorized with an Porsche engine mounted in
pusher configuration on struts above the wing. It had a fully exposed wheel at the bottom of the wing strut. Though it flew successfully, no more were built. ==Variants==