Warsztaty Szybowcowe Orlik / XTG-7

Orlik 2

Designed by Antoni Kocjan, the Orlik 2, which first flew in 1938, was a development of the 1937 14.4 m. Orlik 1. A special model (Orlik 3) was developed for the Olympic design competition for the 1940 games (won by the German D.F.S. Meise). It has unusual airbrakes on the wing undersurface, close to the leading edge, from the root to the wing bend.

Orlik 2

One example came to the U.S., and in WWII was imposed into the military as the XTG-7. Later, flown by Paul MacCready, it briefly held the world altitude record in 1948 at over 9,000 m. in the Sierra wave as well as winning the 1948 and 1949 U.S. Nationals.
Structure: Wood/ fabric wing and tail, wood fuselage.

Orlik 2 / XTG-7
Wing span: 15m / 49.2ft
Wing area: 14.8 sq.m / 162.5 sq.ft
Aspect ratio: 15.2
Empty Weight: 160 kg / 353 lb
Payload: 85 kg / 187 lb
Gross Weight: 245 kg / 540 lb
Wing Load: 16.5 kg/sq.m / 3.32 lb/sq.ft
L/DMax: 24@ 71 kph / 38 kt / 44 mph
MinSink: 0.64 m/s / 2.1 fps / 1.24 kt
Seats: 1
No. Built: 18

Warrior Centaur

Considerations that influenced the layout of the Centaur concept included cabin volume, access, low take-off speed and boat handling duties.

The hull features no transverse step and no forebody chines. This hull accelerates to about seventy percent of take-off speed in displacement mode by which time the water is satisfactorily “hard” and aerodynamic lift takes more than half the weight of the aeroplane off the water. The Centaur encounters no drag hump. This leaves much more thrust available than conventional seaplanes for getting more useful load airborne in a respectable distance. This useful load advantage is further increased by the reduced structural content and weight in the hull, having typically half the beam and surface area of conventional seaplane hulls (floatplanes or flying boats).

The fine bow results in little rotation. Because of the narrow beam, any remaining rotation results in less rise, wave dispersion, spray and wasted energy. The Centaur can handle short steep waves typically twice the height tolerated by equivalent seaplanes.

With the composite vinylester-epoxy laminating resins primary structure largely inset from a secondary shell, the Centaur will tolerate abuse which also aids repair without specialist facilities.

The Centaur’s low stub-wing uses ground-effect aerodynamics to aid low take-off speed. This is helped by a continuous flap through the wing center-section which provides much lift in the propeller slip-stream.
The flap and wings create down-wash on the tail. This down-wash substantially balances the pitching effects of changes in power and flap setting.

Using engineering content near identical to the undercarriage, the outer wing panels can be released and folded back to within the beam of the sponsons, so that the Centaur can be berthed or tied up against the side of a dock or ship, or in marinas. In preparing for flight, as they rotate forward to the locked position, a central stub spar mates with the spar in the wing panel, thus completely removing bending forces from the hinge. The aircraft cannot be flown unless locking is successful and the wings cannot be unlocked unless taxiing at low speed on the surface.

Warrick 1910 Flying Machine

A shoulder-wing monoplane which John A. Warrick of Chicago applied a patent for in 1910 (granted in 1912), the intention being that it would “automatically maintain a proper equilibrium under all ordinary or normal conditions in flight”. This was achieved by a control system that, among other things, allowed the pilot to change the incidence of the somewhat parachute-like negative-dihedral wing. It’s not known if it was built.