HUNGARIAN
GLIDERS
1933-2000
| Type designation: |
Z-03A |
| Name: |
Ifjúság |
| Designer: |
Ferenc ZSEBŐ |
| Class: |
Two-seater trainer |
| General arrangement: |
Middle-wing, tandem seats, fixed tandem wheels, traditional tail unit, mixed metal-wooden structure |
| Crew: |
2 |
| First flight: |
February, 1953 |
| Manufacturer: |
Central Workshop of the Hungarian Aeronautical Association, Dunakeszi |
| Number of built: |
32 |
Short history:
In 1950 the Hungarian Aeronautical Association (MRSz) invited tenders for a two-seater training glider. The specification mirrored the general concept that gliding is simply the first step to train military pilots. The intention of the MRSz was to build 100 gliders of the winner design. The Z-03 Ifjúság designed by Ferenc Zsebő, won the contest.
The designer was completely attached to the general concept and the glider was stressed for basic aerobatic training. The prototype was built by the Central Workshop of the MRSz at Dunakeszi. The glider first flew at February, 1953. Her handling characteristics were considered favorable. The control forces were similar to that of the Cinke (the Hungarian version of the Meise-Olimpia) and climbed in thermals well. However glider pilots did not liked the uncomfortable seats and the seat-type parachutes instead of back-packed ones. Performance data were measured at the Aircraft Department of the Technical University of Budapest. As better values had been gained than expected, the role of the type was extended for training performance gliding and aerobatics as well.
The Z-03 Ifjúság was a middle-wing, tandem two-seater glider with mixed metal-wooden structure. It was certified for cloud flying, basic acrobatics and spins.
The first glider of the serial production first flew at January, 1955. Altogether 32 gliders were built up to April, 1955. The prototype had been exhibited at the Leipzig Fair in 1955 and three glider were exported to Belgium at the same year.
The glider's performance was verified by a couple of remarkable flights. 65 km/h speed was achieved over a 100 km triangle course (1954), 225 km distance was flown with two pilots on board (1955), and 3013 m height gain was reached (1955). At August, 1955, the first student pilot flew his first solo flight with the type. However the first accident also ensued. During an aerobatic training flight the wing-fuselage connection structure was broken and both pilots had to abandon the glider by parachutes. The Aircraft Department of the Technical University of Budapest performed fatigue tests on four Z-03A gliders and the steel structure, which the wing-fuselage connection fitting was attached to, was broken after 275 hours operation. The connection fitting was broken only after 8239 hours, and the wing's wooden structure was intact after the tests. The glider was withdrawn from operation in 1960 due to the result of these fatigue tests.
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Structure: Mixed metal-wooden structure, all light-metal structural elements were protected by electrolyte oxidization.
Wing:
On the half span of the glider's tapered wing Frise-type ailerons, between the ailerons ant the wing root split flaps were fitted. The Göppingen type airbrakes were working on both surfaces of the wing. On the 80% of the span Gö-549 airfoil section were used which turned into Gö-676 sections located virtually beyond the wingtips of 2,32 m, to avoid excessive aerodynamic washout. On the outer half-span geometric washout of -3,5 degree was applied as well. A wing-sweep of -1,5 degree was used on the prototype, however this was eliminated at the serial production due to modified mass distribution.
The one spar wing was built of wood. The wing was covered in front of the main spar by plywood, behind it by fabric. The half wings were connected to the fuselage by three point ball-and-socket joints.
Fuselage:
The fuselage consisted of two parts. The front part was a welded steel-tube structure with fabric covering spanned on shape-forming light-metal ribs. The glider was capable to fly with only one pilot in the front seat, as the back-seat was located at the c.g. The one part canopy opened backward and was fixed at the opened position by a telescopic support rod. There was no instrument panel fitted in front of the back-seat.
The second, rear part of the fuselage had elliptical cross section and was a light-metal monocoque structure with ribs and longerons. The two parts of the fuselage were connected with four pins. The landing gear consisted of a rubber springs nose, and a fixed main wheel. For high winch launches hooks for Y-wire were fitted on both sides of the fuselage.
Tail unit:
The tail unit had traditionally arranged surfaces. All surfaces had light-metal structures. The stabilizers were covered bay light-metal sheets, the control surfaces by fabric.
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| Dimensions: |
| Wing: |
| Span, m: |
15 |
| Area, m2: |
18,4 |
| Aspect ratio: |
12,2 |
| Chord (root), m: |
1,6 |
| Chord (tip), m: |
0,5 |
| Airfoil (root), m: |
GÖ-549 |
| Airfoil (mid-span), m: |
Gö-549 |
| Airfoil (tip), m: |
Gö-676 (virtually beyond the wingtip of 2.32 m) |
| Dihedral, degree: |
3,5 |
| Sweep, degree: |
Prototype: -1,5; serie: 0 |
| Washout: |
Aerodynamic and geometric of -3,5 degree |
| Aileron: |
| Span, m: |
3,87 |
| Mean chord, m: |
0,29 |
| Total area, m2: |
2,65 |
| Balancing: |
Frise |
| Flap: |
| Type: |
Split |
| Area, m2: |
1,84 |
| Relative length, %: |
0,415 |
| Movement (+/-), degree: |
?/? |
| Airbrakes: |
| Type: |
Göppingen |
| Position (upside/downside): |
u/d |
| Total area, m2: |
0,58 |
| Position, % of chord: |
0,4 |
| Horizontal stabilizer: |
| Span, m: |
3,2 |
| Area, m2: |
2,26 |
| Elevator: |
| Span, m: |
3,2 |
| Area, m2: |
1,3 |
| Airfoil: |
Symmetric |
| Balancing: |
Aerodynamic and mass (inner) |
| Trim: |
Yes |
| Vertical stabilizer and rudder: |
| Total area, m2: |
1,4 |
| Rudder area, m2: |
0,96 |
| Balancing: |
None |
| Fuselage: |
| Length, m: |
7,5 |
| Width, m: |
0,67 |
| Height: |
1,2 |
| Cross section, m2: |
0,64 |
| Landing gear: |
| Type: |
Fixed nose and main wheels, tandem arrangment |
| Wheel diameter, m: |
Nose: 0,26; main: 0,42 |
| Masses: |
| Wing, kg: |
? |
| Fuselage, kg: |
? |
| Tail unit, kg: |
? |
| Empty glider, kg: |
290 |
| Gross, kg: |
455 |
| Ballast, kg: |
None |
| Wing loading, kg/m2: |
24,7 |
| Speeds: |
| VNE, km/h: |
200 |
| Max. speed with open airbrakes, km/h: |
200 |
| Max. aerotow speed, km/h: |
130 |
| Max. winch speed, km/h: |
90 |
| Max. speed in rough air, km/h: |
130 |
| Stall speed, km/h: |
63 |
| Performance: |
| Min. sink, m/s (at gliding speed, km/h): |
1,0/72 |
| Best L/D (at gliding speed, km/h): |
22/80 |
| Start methods: |
Winch, Aerotow |
Origin of data and 3-view drawing:
Jereb Gábor: Magyar vitorlázó repülőgépek, Műszaki Könyvkiadó, 1988, Budapest
(Gábor JEREB: Hungarian Gliders, Technical Publishing House, 1988, Budapest)
Gábor FEKECS E-mail: fekecs.gabor@t-online.hu
