The betting propeller, also known as a doughnut engine, is a type of aircraft prop that was originally designed to allow aerobatics and stunt flying. Early models of the aircraft were fitted with a single propeller, while later versions used up to four props. The design earned the nickname ‘doughnut engine’ due to the shape of the exhaust ports on the sides of the engine.
The betting propeller is a single-engine aircraft with conventional undercarriage. The engine is typically mounted above the aircraft’s nose, with the propeller pointing downward. The aircraft has two pilot’s controls, one on either side of the cockpit.
The design allows the pilot to do loops, rolls, and other aerobatic maneuvers, as well as to perform stunts. The high wing makes the aircraft both stable and easy to handle in flight. The aircraft typically reaches a maximum height of a few feet above the ground before it starts to lose any forward momentum due to air resistance, allowing it to be maneuvered with ease.
The first betting propeller was designed and built by a Polish aeronautical engineer named Mieczyslaw Petrucci and an Italian company named Macchi. The pair later founded their own company named Petruzzi-Macchi in 1929, with the first batch of aircraft being delivered in the following year. The aircraft’s distinctive shape made a lasting impression on the aviation community, with the nickname ‘doughnut engine’ being applied to it soon after its introduction.
Aerobatics was one of the main attractions at the Paris Air Show in 1930, with demonstrations by the Petruzzi-Macchi group. The popularity of the design eventually led to the creation of a dedicated aerobatics flight school, the Escuela de Aviación Mieczyslaw Petrucci, in Spain. Several thousand students have passed through the school, which is still open today.
The betting propeller has undergone several modifications over the years. In addition to using more efficient engines, the designers have tinkered with the shape of the aircraft’s nose, which is now pointed and not flat like the early models. The overall silhouette of the aircraft has also been altered, with the width of the fuselage being reduced to save on weight and increase the amount of interior space. Around 30 new versions of the design have been developed since 1930, with a new model being introduced at almost every aviation exhibition held around the world.
The betting propeller is typically associated with high-profile individuals or organizations, with many celebrities having owned the aircraft in the past. The design is also commonly seen at air shows and other types of public events, due to its popularity among celebrities and the general public. Several airlines have also operated the aircraft, with Turkish Airlines being one of the more recent additions to the fleet.
It is often said that beauty and practicality are the main design principles behind the betting propeller. The aircraft are generally streamlined and lightly built, which makes them both easy to maneuver and quick to accelerate. Their high wing and small size make them both agile and easy to handle. The high placement of the engine ensures that the propeller is always visible for dramatic effect during flight, even when the aircraft is in a tight turn or upside down.
The distinctive shape of the betting propeller is the result of a combination of factors. The overall design of the aircraft was heavily influenced by the Italian aviator and engineer Giuseppe Gabrielli, with its pointed nose being a tribute to Gabrielli’s ‘Duck’ shape. The name ‘Duck’ is also sometimes assigned to the original Petruzzi-Macchi design, which had a flat nose and was intended for use as a dive bomber.
The aircraft’s compact size and light weight make it well-suited for transport, especially when coupled with its single-pilot design. The shape of the air inlet suggests that the cabin could be pressurized, which would make the experience of a flight much more enjoyable for the traveler.
Due to its popularity, the betting propeller has been reproduced in many forms. There are at least two main variations of the design, with the first being the single-pilot airplane described previously. This version has a two-piece canopy, which encloses the entire cockpit. The other version has a complete, single-piece canopy that can be opened for increased visibility. The design was also adapted to become the first hot-weather aircraft, with degradable nozzles and wing tips used for fire-fighting duties.