Experiments in different material finishes in recent years have revealed some interesting relationships in Re and paper models. Performance of origami and compound origami structures improves markedly with the introduction of smooth paper, though this is also aided by the paper's higher mass and consequently better penetration. Later gliders with three-dimensional fuselages use a lightweight construction optimised for flight performance.

By comparison the wings of a four passenger airplane have a Reynolds Numbers of up to about 6,000,000. Also, remember the transition from laminar to turbulent? That happens at a Reynolds number of no less than about 10,000, so the first ½ to ¼ of the flow over a paper airplane's wing is laminar. Since the Reynolds Number is much less than for full sized airplanes, this means viscosity is much more dominant, resulting in more drag, and more difficulty in creating lift. Similar content to 1st book, concerning why paper airplanes fly, more hands-on experiments to demonstrate principles. Also a teachers guide for this book is available from the publisher with more paper airplane information] In general, there are four aerodynamic forces that act on the paper aircraft while it is in flight:Ongoing development of folded/origami gliders over the same period has seen similar sophistication, Its important to realize the basics of why paper airplanes fly, and why full size airplanes fly, are identical. They create lift and drag, and are stable or unstable for the same reasons. However paper airplanes look different than most airplanes. The reason they generally look different is for very practical reasons, but not necessarily due to aerodynamics. There are also some definite aerodynamic differences between paper airplanes and full size planes. These difference are not so apparent, but do affect how paper airplanes fly. First, fold the top left corner all the way down so it meets the right edge of the paper. You’ll then unfold, as this will be a guiding crease. Paper plane enthusiast sets flight record" by Justin McCurry in Tokyo, guardian.co.uk, 27 December 2009 16.03 GMT. Retrieved 2009-12-31.

There are few technical references for paper airplanes. Naturally paper airplane books talk about paper airplane aerodynamics, but usually in a simplistic manner. There are many reference to low speed flight which are applicable to paper airplanes. Here are a few. 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. Professors Ninomiya and Mathews (see sections below) 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. A unique development of Prof. Mathews is the Papercopter, a model helicopter whose 'wing' is a trimmable annular ring which, using rotational aerodynamics to provide good forward flight performance without need for a tail rotor. A model helicopter 'body' is suspended beneath the ring, and uses airflow to stabilise itself in the direction of flight, much like a weather vane.

Hobbies

As mentioned in section 2.2, where a paper airplane balances is called the Center of Gravity (CG), and there is a specific CG position known as the Neutral Point which provides neutral pitch stability. If the airplane has a CG ahead of this point, the plane is stable, if its behind this point its unstable. Naturally all airplanes without computer assisted flight controls need a CG ahead of their neutral point. For rectangular wings the neutral point is ¼ of the distance from the nose to the tail. For delta wings (such as the common dart paper airplane) the neutral point is ½ of the distance from the nose to the tail. First you fold the paper in half lengthwise, and then unfold. This initial crease is simply a guideline for the next folds.