The Potez 28 was a French aircraft designed in the 1920s to set distance records, built in both

sesquiplane 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 a ...

and

monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...

versions. Only two were completed but both set several long distance records.

Design and development

The Potez 28, known also as the Potez 28/2 or the Potez 28 G.R. (''Grands Raids'' or long distance flights, a standard French description of such types) was a close relative of both the Potez 25 and the Potez 25 G.R., all single engine sesquiplanes. In its original

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 ...

form it was particularly like the latter, though strengthened and somewhat enlarged with an upper wingspan increased by 19% to allow for the weight of extra fuel. Unusually for such a large machine, it was a single bay biplane, with two spar wings. The lower wing was both shorter and narrower (55%) in

chord Chord may refer to: * Chord (music), an aggregate of musical pitches sounded simultaneously ** Guitar chord a chord played on a guitar, which has a particular tuning * Chord (geometry), a line segment joining two points on a curve * Chord ( ...

than the upper, resulting in it having only 36% of the area. Pairs of interplane struts leaned outwards and diverged toward the more widely separated upper wing spars. The upper wing was supported over the

fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...

by further pairs of outward leaning struts from the upper fuselage, converging to its spars. The fuselage of the Potez 28 was flat sided, with rounded decking and two 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 ...

s placed well behind the upper wing. There was a cut-out in the trailing edge of the upper wing to improve the pilot's field of view. Large external supplementary fuel tanks could be carried below the fuselage to extend the range. The sesquiplane was powered by a

Renault 12Kg Groupe Renault ( , , , also known as the Renault Group in English; legally Renault S.A.) is a French multinational automobile manufacturer established in 1899. The company produces a range of cars and vans, and in the past has manufactured ...

engine, driving a two blade

propeller A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...

. At the rear the

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 ...

was small and roughly quadrantal, topped by the horn of the

balanced rudder Balanced rudders are used by both ships and aircraft. Both may indicate a portion of the rudder surface ahead of the hinge, placed to lower the control loads needed to turn the rudder. For aircraft the method can also be applied to elevators and ...

. It had a fixed tail wheel undercarriage with single main wheels mounted on vertical, streamlined, shock absorbing legs attached to the lower fuselage. These were hinged on trailing struts to the outer lower fuselage and on inner struts to its central lower underside. The first Potez 28 was first flown in the first half of 1926. A second Potez 28 was built, powered by a W-12 configuration Farman 12We engine. The three cylinder banks each had their own cowlings. During 1927 it was converted into a

, with a parasol wing with an area of , almost the same as the biplane. Its wing had a straight

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, ...

but there was straight taper on the trailing edges of the outer panels. The crew of two were now enclosed under a long, continuous canopy. It was test flown in May 1927.

Operational history

The Potez 28 and 28M were built to compete with the Breguet 19 GR over long distances. The Renault engined machine set a new world distance record with a flight from

Paris Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. S ...

Basra Basra ( ar, ٱلْبَصْرَة, al-Baṣrah) is an Iraqi city located on the Shatt al-Arab. It had an estimated population of 1.4 million in 2018. Basra is also Iraq's main port, although it does not have deep water access, which is hand ...

, piloted by the brothers Ludovic and Paul Arrachart. Leaving Paris on 26 June they landed at

RAF Shaibah The Royal Air Force (RAF) is the United Kingdom's air and space force. It was formed towards the end of the First World War on 1 April 1918, becoming the first independent air force in the world, by regrouping the Royal Flying Corps (RFC) and ...

, a few kilometers from Basra, with a broken fuel pipe, having covered a distance of in 26 hours 30 min. The Potez 28M set six speed, distance and duration records whilst carrying loads of and over distances between . It was lost during the take-off for a record attempt, a flight from Etampes to

Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of ...

, when the weight caused a tyre to burst; the pilots escaped unhurt.

Variants

;Potez 28 G.R.: Sesquiplanes, one powered by a

V-12 engine and the second by a Farman 12We engine and fitted with oil coolers on the fuselage sides. ;Potez 28/2 Lionel de Marmier-1927

;Potez 28M: Parasol wing monoplane conversion of the second aircraft, powered by the Farman 12We engine.

Specifications (Biplane, Renault engine)

References

{{Potez aircraft 1920s French experimental aircraft 028 Sesquiplanes Parasol-wing aircraft Single-engined tractor aircraft Aircraft first flown in 1926