The Dąbrowski D.1 Cykacz (Ticktock) was an unusual, small, low-powered, single-seat

biplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While ...

, intended to provide wider access to flying. Though it was exceptionally aerodynamically clean, it was under-powered and had limited range. Only one was built.

Design and development

Jerzy Dąbrowski's first aircraft design, produced early in 1924 while he was a student at the

Warsaw Technical University The Warsaw University of Technology ( pl, Politechnika Warszawska, lit=Varsovian Polytechnic) is one of the leading institutes of technology in Poland and one of the largest in Central Europe. It employs 2,453 teaching faculty, with 357 professor ...

, was an unusually clean biplane with an entirely wooden structure. Its one-piece wings were built around two

spars The United States Coast Guard (USCG) Women's Reserve, also known as the SPARS (SPARS was the acronym for "Semper Paratus—Always Ready"), was the women's branch of the United States Coast Guard Reserve. It was established by the United States ...

and had

plywood Plywood is a material manufactured from thin layers or "plies" of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another. It is an engineered wood from the family of manufactured ...

covered

leading edge The leading edge of an airfoil surface such as a wing is its foremost edge and is therefore the part which first meets the oncoming air.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 305. Aviation Supplies & Academics, ...

s, with fabric covering elsewhere. The leading edges were straight and unswept out to semi-elliptical tips and the inboard part of the wings had parallel chord inboard but tapered outboard. These outboard regions carried tapered

ailerons An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in Flight dynamics, roll (or ...

, though only on the upper wing; ailerons apart, the upper and lower wings were identical. The great majority of biplanes have had upper and lower wings braced together with

interplane strut In aeronautics, bracing comprises additional structural members which stiffen the functional airframe to give it rigidity and strength under load. Bracing may be applied both internally and externally, and may take the form of strut, which act in ...

s but the Cykacz had none; instead, the fairly thick section wings were

cantilever A cantilever is a rigid structural element that extends horizontally and is supported at only one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a canti ...

s. The upper wing was supported high over the fuselage on a pair of outward-leaning N-struts with the forward V faired in and the centre of the lower wing was attached to the bottom of the fuselage. There was significant stagger. The Cykacz was powered by a

Blackburne Tomtit The Blackburne Tomtit was a 670 cc V-twin aero engine for light aircraft that was designed and produced by Burney and Blackburne Limited. Burney and Blackburne was based at Bookham, Surrey, England and was a former motorcycle manufacture ...

, an air-cooled

V-twin engine A V-twin engine, also called a V2 engine, is a two-cylinder piston engine where the cylinders share a common crankshaft and are arranged in a V configuration. Although widely associated with motorcycles (installed either transversely or longi ...

. The whole fuselage was a smooth, oval section

semi-monocoque The term semi-monocoque or semimonocoque refers to a stressed shell structure that is similar to a true monocoque, but which derives at least some of its strength from conventional reinforcement. Semi-monocoque construction is used for, among ot ...

structure with wooden frames and ply skin and the engine was in its forward part, though with its cylinders exposed for cooling. The small diameter propeller, designed by Dabrovsky, had a dished

spinner Technology *Spinner (aeronautics), the aerodynamic cone at the hub of an aircraft propeller * Spinner (cell culture), laboratory equipment for cultivating plant or mammalian cells * Spinner (computing), a graphical widget in a GUI * Spinner (MIT Med ...

that blended into the fuselage's lines. The biplane's single, open

cockpit A cockpit or flight deck is the area, usually near the front of an aircraft or spacecraft, from which a Pilot in command, pilot controls the aircraft. The cockpit of an aircraft contains flight instruments on an instrument panel, and the ...

was under the upper

trailing edge The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge meets.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 521. Aviation Supplies & Academics, 1997. ...

where there was a cut-out to increase the pilot's field of view. The Cykacz had a conventional

empennage The empennage ( or ), also known as the tail or tail assembly, is a structure at the rear of an aircraft that provides stability during flight, in a way similar to the feathers on an arrow.Crane, Dale: ''Dictionary of Aeronautical Terms, third ed ...

with a

fin A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. Fin ...

that was integral with the fuselage and ply covered. Its

tailplane A tailplane, also known as a horizontal stabiliser, is a small lifting surface located on the tail (empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters and gyroplane ...

was, like the wings, in a single piece with a ply-covered

and fabric elsewhere. It was mounted on the top of the fuselage and, together with its separated

elevators An elevator or lift is a cable-assisted, hydraulic cylinder-assisted, or roller-track assisted machine that vertically transports people or freight between floors, levels, or decks of a building, vessel, or other structure. They are ...

, was roughly elliptical in plan. Its

rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally aircraft, air or watercraft, water). On an aircraft the rudder is used primarily to ...

, which was rounded, low but broad, extended down to the keel. These control surfaces were wooden with fabric covering. Its

undercarriage Undercarriage is the part of a moving vehicle that is underneath the main body of the vehicle. The term originally applied to this part of a horse-drawn carriage, and usage has since broadened to include: *The landing gear of an aircraft. *The ch ...

was fixed and conventional, with a track of . A single axle was held on two V-struts from the lower fuselage, with rubber chord shock absorbers. The V-struts had ply fairings and the axle was enclosed within a small lift-giving

aerofoil An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine. ...

. When first tested, the Cykacz was reluctant to take-off, partly because the Tomtit engine was unreliable and had to be kept below the high output shaft speeds for which the propeller was designed. Babinski took it on its first flight on 26 February 1925. Once off the ground it proved responsive and easy to fly and to land, which it did at low speeds and in short distances. A series of short flights led to some empennage modifications and the fitting of a better-matched propeller enabled the Cykacz to log a total of about forty rather short flights. Its engine remained unreliable and the biplane was both underpowered in flight and of short range. It appeared in an exhibition at the Warsaw Technical University in August 1925 but by 1926 Dąbrowski had abandoned it and was working on a new design.

Specifications

References

{{reflist, refs= {{cite book, title=Polish Aircraft 1893-1939, last=Cynk, first=Jerzy, year=1971, publisher=Putnam Publishing, location=London, isbn=0 370 00085 4, pag
113-5
url-access=registration, url=https://archive.org/details/polishaircraft1800cynk/page/113 {{cite journal , date=January 1924 , title=Nowy platowiecz sportowy, journal= Mlody Lotink , volume=1924 , issue=1, url=http://bequickorbedead.com/snapshot/detail/samolot-sportowy-d-1-cykacz-konstrukcji-jerzego-dabrowskiego and {{cite journal , date=June 1925 , journal= Mlody Lotink , volume=1925, issue=6 , title=images , url=http://bequickorbedead.com/snapshot/detail/samolot-sportowy-d-1-cykacz-konstrukcji-jerzego-dabrowskiego 1920s Polish sport aircraft Biplanes Single-engined tractor aircraft Aircraft first flown in 1923 Conventional landing gear