Read an Excerpt
Airigami
Realistic Origami Aircraft
By Elmer A. Norvell Dover Publications, Inc.
Copyright © 2006 Elmer A. Norvell
All rights reserved.
ISBN: 978-0-486-13258-7
CHAPTER 1
Symbols/Structures
Flight Principles
Flight Worthiness of Paper Models - Gravity, Thrust, Lift, and Drag
Gravity and Thrust
Gravity and Thrust are mostly fixed. To change gravity significantly you must get out of Earth's gravity by going out in space or living on a different planet. Currently there are not many options. Thrust is limited by the strength and technique of whoever is flying the model. There is some difference in experienced paper airplane pilots, however mostly this is a matter of practice and trial and error. Launching aircraft at the correct attitude and when outside launching into the wind may improve the flight duration and performance.
Lift
Most efficient lifting bodies tend to be slow and have a lot of inherent drag. The lifting foil is a good example of a duration-type paper plane.
The foil is effective because it maximizes wing area by eliminating the fuselage and other control surfaces and projections. There are not many scale examples of these. Good sources of these type full-scale aircraft are the X- Planes programs. The X-20 Dyna-Soar and the X-23 Prime, X-24 (A,B and C), X-30 A, X-33, X-38 and the X-45A UCAV are all good examples of lifting body designs. These aircraft are much more difficult to trim and control than dart-type conventional jets. They are not as aesthetically appealing nor as well known as conventional aircraft. The lifting body design is important and has led to the development of the reusable space shuttle.
Dart-type jets do not rely on lift as much as they do thrust. Designs include F16, F16-XL, XB-70 Valkyrie, X-29, and SAAB Gripen which are likely the best flyers in this book. They are fast and can fly long distances. They have relatively low drag and slightly less wing area. They are a good combination of speed and duration.
Drag
Drag is undesirable and inhibits flight speed and duration for paper airplanes. More projections such as the XB-70 Valkyrie (page 35) compared to the F-16XL (page 25) equates to more drag on the XB-70. However, larger wing area to weight ratios cause increased drag and reduces overall speed.
Concorde
The Concorde was the first and only commercial jet to cruise at speeds faster than the speed of sound. This Mach 2 plus aircraft was the product of cooperation between the Sud-Aviation of France and the British Aircraft Corporation (BAC). This SST (Super-Sonic Transport) began operation in 1976 and flew up to 144 passengers each flight until it was taken out of service 25 years later.
Start with 5"x 5" (square) colored/printed side down
Boeing X-45A UCAV
The Boeing X-45A Unmanned Combat Aerial Vehicle (UCAV) is the test bed for combat aircraft flown without a pilot on-board. The vehicle can be directed via satellite control or fly autonomously (self-guided) by pre-programmed computer. The vehicle is stealthy and there is no political pressure to rescue a pilot if things go wrong. Could the future be combat airplanes without pilots in them?
AURORA
This top-secret aircraft may or may not exist. No verified sightings have been made of this "Black Project." The depiction here is my fantasy of Bill Sweetman's interpretation of what this pulse-jet may look like, but feel free to come up with your own variation. The "truth" is out there ...
Start with square colored/printed side down.
F-16 Fighting Falcon
The F-16 Fighting Falcon developed by General Dynamics is one of the most prolific fighter aircraft flying today. Over 90 countries have this airplane in their inventory, over 4,000 have been produced. The F-16 flies at over Mach-2 (twice the speed of sound).
Start with 8.5" x 11" rectangle colored side down.
Optional scale-like wing design. Model flies in either configuration.
Mountain-fold along lateral line and valley-fold small distance as shown through all layers. (This actually looks and works better than the more complicated double reverse folds along the same lines on wings, see Raptor instruction steps 10-12 (on page 57), if you would like to give it a try.)
F-16XL Experimental
The F-16XL Experimental is a one of kind F-16 fitted with a delta wing. This aircraft was flown by a female test pilot, Marta R. Bohn-Meyer. Though never put into production, the aircraft demonstrates the versatility of the basic F-16 design.
Start with 8.5" x 11" rectangle colored side down
SAAB Gripen/Rafale
Designed for my college friend Rick, a Viggen and Gripen pilot. Sweden prides itself on producing their own aircraft. As a result of WWII, Swedish aircraft are designed for short take offs and landings which enable them to be launched from unconventional surfaces such as remote roadways and unimproved surfaces. Eliminating the requirement for airports, the Swedes can disperse their aircraft throughout the country.
Start with 8.5" x 11" rectangle colored side down
XB-70 Valkyrie
Only two XB-70 Valkyries were built. This Mach-3 Bomber was to be a part of the US strategic nuclear delivery system against the former Soviet Union. Sadly, after the destruction of one of the Valkyries during a photo shoot (a chase aircraft was sucked into the XB-70's enormous vertex) the program was cancelled in favor of ICBM missiles. The program became the foundation for the B-1 Lancer. The remaining XB-70 is on display at Wright-Patterson Air Force Base, Ohio. This model is dedicated to Valkyrie pilot, Fitzhugh L. Fulton, Jr.
Start with 8.5" x 11" rectangle colored side down
Rocket Racer
The Rocket Racer idea is the mind spring of the sponsors of the X-Prize which the StarShipOne designed by Burt Rutan was able to win by creating a spacecraft that could enter low earth atmosphere and return to accomplish the same feat again in two weeks. The Rocket Racers are to be a sort of "NASCAR" race, only using rocket powered aircraft instead of cars.
Start with 8.5" x 11" rectangle colored side down
Grumman X-29 Experimental
The Grumman X-29 experimented with forward swept wings to destabilize the aircraft. This instability had the potential to make the aircraft more maneuverable than conventional designs. The actual airplane required over 20 sophisticated computers to keep the plane in control. Fortunately, your paper model only requires a little patience to trim.
Start with 8.5" x 11" rectangle colored side down
F-22 Raptor
The F-22 Raptor can fly supersonic without afterburners and uses stealth technology to achieve air superiority. It is especially adapted for Suppression of Enemy Air Defenses (SEAD) and air-to-air combat. It is the newest addition to the US Air Force, taking the place of the aging F-15 Strike Eagle.
J-2 Experimental
The J-2 was Japan's version of the Me-163 German point interceptor. The J-2 was much larger and had two rocket engines (German made) instead of one, like the Me-163. It was to be used to defend the main island from a B-29 invasion, however, Japan surrendered while the first 25 J-2s were being assembled inside of a cavern carved in Mount Fuji.
Start with 8.5" x 11" rectangle colored side down
F-117 NIGHTHAWK
The mis-designated F-117, "F" indicates a "fighter," was actually a relatively slow bomber. It could only carry two Precision Guided Munitions (PGM) bombs and had no guns to protect itself. Its power laid in its invisibility to radar. The "F" designation assisted in recruiting the best fighter pilots to fly this seemingly vulnerable machine.
SR-71 Blackbird
The legendary SR-71 Blackbird set records for speed and altitude even as it was being decommissioned. It survived many years of service as a high-altitude reconnaissance vehicle and still inspires awe in its streamline features.
Start with 8.5" x 11" rectangle colored side down
WWII Aircraft Base
JU-87 Stuka/P-51 Mustang/Corsair/Spitfire/Zero
Start with square paper colored side up. Use at least a 10 inch square for the first attempt. Foil side up if using foil paper to produce a shiny model. Note: Foil model will retain the shape better and starting with the foil side down, ink markings may be added for additional realism.
German Ju-87 Stuka: Fold the wings as indicated. Try to make the folds symmetrical as possible by pinching the wing tips as these folds are made. Wrap the paper gently around the shaded area on the tail. (Partly unfold to keep from tearing the paper)
Finish model as shown and decorate to suit taste.
US Navy Corsair: round wing tips out. Fold the wings as indicated, but not crisply, use soft folds. Try to make the folds symmetrical as possible by pinching the wing tips as these folds are made. Wrap around the shaded area on the tail. Shape canopy rounded and smaller than Stuka.
Finish model as shown and decorate to suit taste.
British Supermarine Spitfire: Wrap paper at tail (gray area) so that it is all one surface. Round wing and wing tips by making many tiny mountain folds.
Finish model as shown and decorate to suit taste. Note the aesthetic elliptical wing. This will require numerous small mountain-folds to produce a nice result.
Japanese Zero: round wing and wing tips.
Finish model as shown and decorate to suit taste.
A-10 Warthog
The A-10 Warthog was originally designed as a tank killer. Nearing its useful life, the first Gulf War used the A-10 with Precision Guided Munitions (PGM) and ensured its long term viability as a staple for the national defense.
Repeat on the right side. Result should look like 8.
How to Trim/Airplane Terms
Trimming paper airplanes is much like trimming full-scale aircraft. Small adjustments to the edge of the wings and stabilator (combination of rudder and elevator) make big changes to the flight path. A properly trimmed airplane will fly longer and straighter. I recommend you keep the wings or canards and the rudders straight and neat as possible and only adjust the elevators as shown to control the flight path.
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Excerpted from Airigami by Elmer A. Norvell. Copyright © 2006 Elmer A. Norvell. Excerpted by permission of Dover Publications, Inc..
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