Paper plane
A paper plane is a toy aircraft, usually a glider, made out of a single folded sheet of paper or paperboard. It typically takes the form of a simple nose-heavy triangle thrown like a dart.
The art of paper plane folding dates back to the 19th century, with roots in various cultures around the world, where they have been used for entertainment, education, and even as tools for understanding aerodynamics.
The mechanics of paper planes are grounded in the fundamental principles of flight, including lift, thrust, drag, and gravity. By manipulating these forces through different folding techniques and designs, enthusiasts can create planes that exhibit a wide range of flight characteristics, such as distance, stability, agility, and time aloft. Competitions and events dedicated to paper plane flying highlight the skill and creativity involved in crafting the perfect design, fostering a community of hobbyists and educators alike.
In addition to their recreational appeal, paper planes serve as practical educational tools, allowing students to explore concepts in physics and engineering. They offer a hands-on approach to learning, making complex ideas more accessible and engaging. Overall, paper planes encapsulate a blend of art, science, and fun, making them a unique phenomenon in both childhood play and academic exploration.
History
Paper airplanes are known to have been made as far back as the mid 19th century, based on an American children's book describing their construction from 1864.The construction of a paper airplane, by Ludwig Prandtl at the 1924 banquet of the International Union of Theoretical and Applied Mechanics, was dismissed as an artless exercise by Theodore von Kármán:
Prandtl was also somewhat impulsive. I recall that on one occasion at a rather dignified dinner meeting following a conference in Delft, Holland, my sister, who sat next to him at the table, asked him a question on the mechanics of flight. He started to explain; in the course of it he picked up a paper menu and fashioned a small model airplane, without thinking where he was. It landed on the shirtfront of the French Minister of Education, much to the embarrassment of my sister and others at the banquet.
In recent times, paper model aircraft have gained great sophistication, and very high flight performance far removed from their origami origins, yet even origami aircraft have gained many new designs over the years, and gained much in terms of flight performance.
There have been many design improvements, including velocity, lift, propulsion, style, and fashion over subsequent years.
Advanced paper gliders
Developments
Paper gliders have experienced three forms of development in the period 1930–1988:- High flight performance
- Scale modeling
- Use of CAD software
including the addition of the following construction refinements
- Increased fold-count, sometimes of an intricate nature
- Explicit kirigami as a component of design
- Requirements for additional ballast to ensure flight performance
Technological introductions
- Inexpensive CAD software for 2D part design
- Widespread manufacture, and inexpensive nature of acetal air-annealed glues, e.g. Bostik Clear-bond.
- Inexpensive ink and laser computer printers, for accurate aircraft part reproduction
- The advent of the Internet, and widespread information sharing
Material considerations
However, unlike balsa gliders, paper gliders have a far higher strength-to-thickness ratio:
Directions in advanced paper aircraft design
Unmodified origami paper aircraft have very poor glide ratios, often not better than 7.5:1 depending on construction and materials. Modification of origami paper gliders can lead to marked improvements in flight performance, at the cost of weight and often with the inclusion of aerodynamic and/or structural compromises. Often, increases in wing loading can encourage breakdown of laminar flow over a wing with a hybrid of origami and glued and taped construction.Professors Ninomiya and Mathews developed more directed design strategies in the late 1960s and the 1980s. Previously, paper model aircraft had been designed without an emphasis on performance in flight. By using aerodynamic design, and fluid dynamics, both professors were able to design models that exceeded previous flight performance criteria by a very wide margin. Ranges of flight increased from the typical 10+ meters to 85+ meters, depending on energy input into the gliders on launch.
At present, the work of the two professors remains the last serious research work on improving the flight performance of paper model gliders.
Collaborative work by enthusiasts through online forums and personal websites are mostly developments of these original glider types.
In the field of scale model design, there are at present many possibilities for advanced design. Profile gliders encounter a limitation for improvement of flight performance based on their wing types, which are typically curved-plate aerofoils. In addition, fuselages are either balsa-paper or paper laminates, prone to warping or breakage over a very short time.
Improvement in performance is possible through modelling three-dimensional fuselages which encourage laminar flow, and in internally braced wings which can then have high-lift aerofoil profiles, such as the Clark Y or NACA 4 or 6 series, for high lift.
White Wings
In Japan in the late 1960s, Professor Yasuaki Ninomiya designed an advanced type of paper aircraft, which were published in two books, Jet Age Jamboree and Airborne All-Stars. Designs from these books were later sold as the 'White Wings' Series of paper glider packs from the 1970s to the present day.White Wings are a stark departure from conventional paper aircraft, in that their fuselages and wings are paper templates cut and glued together. They were designed with the aid of low-speed aerodynamic engineering design principles. Construction of the models is of Kent paper, a grade of cartridge paper sold in Japan.
The early models were explicitly hand drawn, but by the 1980s these had their parts drafted with the use of CAD software.
Ninomiya's designs also included, for the first time in any paper model, working propellers driven by airflow, in particular for his profile scale models of the Cessna Skymaster and Piaggio P.136 of 1967. Noteworthy as well was the careful design of gliders so that they could fly without ballast – his F-4 Phantom II model is able to be flown immediately without recourse to paperclips, etc.
The high performance gliders have fuselages that are kept rigid by the use of a balsa fuselage profile bonded to the paper components. The paper used is quite heavy, approximately twice the weight of standard drawing cartridge paper, but lighter than lightweight cardboard. Original White Wings were entirely paper, requiring patience and skill. Later however, balsa-wood fuselages were used, and White Wings were sold "pre-cut", making construction easier. The aerofoil used is a Göttingen 801, and a pattern is supplied as a cutout part of each kit.
Paper Pilot
In 1984, Professor E.H. Mathews, lecturer in Thermodynamics at the University of the Witwatersrand, South Africa published his first compendium of high-performance model aircraft. This book was Paper Pilot. This book was very successful, leading to additional volumes, Paper Pilot 2, Paper Pilot 3, 12 Planes for the Paper Pilot and Ju 52, a stand-alone book featuring a scale model. Unpublished models include an Airbus A320 scale model much like the Ju 52, seen on the Tekkies youth program in 1996.The books featured patterns of parts printed on lightweight cardstock, to give the aircraft good flight penetration performance for long-distance flight.
Public interest in the gliders, and their publishing success, allowed some of the development to be broadcast on South African television during 1988 on the first book's release, and again 1993, to coincide with a national paper aeroplane competition tied to Paper Pilot 3's release. Aerodynamic design of the gliders was achieved making use of an optimised small wind tunnel - the flat-glider Britten Norman Trislander was filmed in this facility, with weight balances being used to demonstrate the optimisation of flight. The design of parts of the gliders was achieved using Autodesk AutoCAD R12, then the most advanced version of this CAD software, and one of the first publicly available paper model aeroplanes designed using this technology.
Construction of the gliders closely parallels that used in the White Wings series of gliders of Dr. Ninomiya for flat gliders. Later gliders with three-dimensional fuselages use a lightweight construction optimised for flight performance. Innovations include functional wheeled undercarriage which does not contribute to the drag budget while permitting good landings.
Paper pilot gliders make use a curved-plate aerofoil shape for best performance. Their design, like the White Wings gliders, is very sensitive to trim, and in fact have the capacity to make indoor flights in confined spaces under average conditions. Most in initial editions are equipped with catapult hook patterns, and demonstrate an ability to fly the length of a Rugby pitch when so launched.
Later editions and gliders were equipped with a bungee hook, the construction of which was included in Paper Pilot 3 and 12 Planes for the Paper Pilot. The bungee system publish parallels, at a smaller scale, the practice used in radio controlled and full-size sailplane launches, at a fraction of the cost and complexity. To date, this is the only known example of such a launch system applied to a paper model aeroplane type published in book form. Flight performance on bungee is very good - one glider in particular, a scale model U-2 had demonstrated flight performance in excess of 120 meters, on bungee hook launch.