More Flying 'Round: real saucers (sort of) - Part 2

When researching this topic, as mentioned earlier, there was more stuff to this that I could confortably deal with in one post. If we look at it from the pre-history of flight to the great revolutionary period of development with the second world war, there is plenty to look at. While many of the "round" aircraft of the first half of the 20th century were often not much more than curiosities, the round shape would be revisited, sometimes to take advantage of some of the more surprising aerodynamic effects of controlled airflow.

The Cold War

Much of the aviation research work generate by the Luftwaffe in World War II was captured by the Allies after the wall, as well as equipment and perhaps more importantly personnel. Fans of a genre referred to as Luft'46, often extol the amazing performance of many of the aircraft designs that were being put to paper and could have theoretically been put into production by the Germans if the war had continued. The had by this time already designed ocean crossing jet bombers, supersonic fighters, transcontinental missiles and advanced tactical missiles such guided air to surface missiles. In practice, it is doubtful they could have implemented the wide scope of proposals given the dire situation of Germany at the time. It is telling that in spite of all the captured material, very few of these designs made it more or less directly from those blueprints to a production model in either the Soviet Union or the United States (and yes, there are a few exceptions). Still, a great deal of their ideas were applied such as swept wings and engine layouts.
     The Cold War created a golden age of military R&D. It would in a very real sense be undone by the great cost of the weapons systems being developed. However in the 50s, when enough time had passed to make anything developed at the end of World War II thoroughly obsolete, it seemed money would be thrown at any vaguely promising advanced idea.

Among the many research air vehicles developed during the Cold War, several of the shapes tried out for vertical take off had vaguely saucer-like shapes.  In the end, none proved truly practical.

     The Heikel annular wing designs lived on in some post war designs carried out by the allies after the war for high performance vertical take-off aircraft (Note: to what extent isn't certain, since the ability to take off vertically by basically aiming propulsive forces down should be fairly obvious). The French Coleoptere was very reminiscent of the Heinkel design. It consisted of a very powerful jet engine housed in a fuselage surrounded by its  wing. On it's test stand it gives off a very futuristic look. In spite of this, it hardly ever truly flew. The craft was flown tethered and found difficult to control. Still, untethered flights were attempted, but it crashed early in its development program. It looked really cool, but it flew like a brick balanced on a skewer.
     The US also tried tail sitter designs, although not in that form, and while they did fly, they were found to be nearly impossible to land. They did try other forms of VTOL, such as simple fan powered hovering. The Army tried various designs that mounted powerful fans to lift infantrymen and behave as a kind of flying jeep or platform. Some of these must have been positively frightening as the infantryman/pilot would stand just inches above the rapidly whirling blades (the DeLackner DH-5 Aerocycle and the Hiller VZ-1 Pawnee). In spite of this, the practicality of such as craft was fairly limited and did not offset traditional light helicopters or ground vehicles.

The Coanda Effect machines

Henri Coanda was a Romanian engineer who invented the first jet airplane in 1910(!). In the process of testing his aircraft he observed the effect that would carry his name. It is interesting to note that he had the presence of mind to observe that the engine's flaming jet exhaust began to wrap around the flame deflectors and hit the fuselage of his very inflammable aircraft while he was simultaneously crashing it. To put it briefly (and over simply), a rapidly flowing fluid will tend to adhere over the surface it is flowing. You can try it out by feeling the air flow around a can of soda when you blow on it.
     As he examined the effect, he postulated that he could create a new method of propulsion that would not make use of a propeller because the rapidly flowing air would create a region of low pressure. If the effect was created above the craft it could generate sufficient lift to fly the craft without wings. He explored the effect and proposed a saucer like aircraft that would use the Coanda effect alone to fly. During the war he continued his research and afterwards patented the idea as a flying saucer.
     The idea was picked up by a couple of aerospace companies, but perhaps more notably by the Avro Canada aviation company. The idea was to create a craft that could use the Coanda effect to lift off vertically, and once at altitude would shift to forward flight using its basic shape as the airfoil. The most ambitious of these was to use an extremely thin saucer like wing to allow the craft supersonic performance. Avro first had to test out the idea and it did so with an early subsonic prototype called the Avrocar.

The Coanda Effect describes how a stream of rapidly moving air will follow the contours of the shape it is flowing over. A coanda effect craft will achieve lift by blowing air pressurized by some mechanism out the sides of the craft. This air curves around the periphery and accelerates surrounding air creating a large volume of low pressure above it. Note that the Avrocar's jet exhaust slot is around the very edges of the craft. The intake for the engine is NOT the main source of lift, although it does contribute. Instead the rapidly flowing air from the edges pulls the air around it creating low pressure over the entire upper surface.

     The Avrocar VZ-9 was developed using US Army funding (as part of the flying jeep program) and the US Air Force, to study the use of the Coanda Effect for a future VTOL fighter. Unlike a conventional jet aircraft, these Coanda Effect aircraft were intended to fire the exhaust radially around the edge of the aircraft. This would create the rapidly flowing stream of air around the edge of the body creating low pressure above it and high pressure below. In practice, the aircraft never proved easy to fly. At low altitudes, the craft's lift was augmented by the ground effect of the exhaust gas being trapped underneath it. As it rose, the gases would escape unevenly out one side or another causing serious instability. It appeared that the benefits of using this effect would be much harder to realize than at first thought (added to the difficulty of developing a suitable radial jet engine). While more advanced versions of the design were proposed, in the end the Avrocar never flew more than a few feet off the ground and was canceled.
     In spite of the failure of various Coanda Effect saucers, the effect is used to enhance the lift of various aircraft by controlling the flow of air over wings and control surfaces.

Dream Saucers

Various designers have proposed serious designs for flying saucer like craft. Some perhaps inspired by the popular accounts of UFOs, others by the lure of VTOL and new ways of flying. Unfortunately, after the war the economic costs of creating radical new aircraft designs meant that unlike the inventors of earlier days, many of these ideas remained as nothing more than paper drawings and mock-ups.

    French aviator Rene-Couzinet designed what I considered one of the prettiest aircraft ever, the Couzinet Arc-en-Ciel. In 1933 this aircraft made the first non-stop crossing from Africa to South America. Couzinet's life though was apparently marked with the kind of up and downs associated with very headstrong designers. Somehow he ended up in Brazil after the war designing his dream aircraft, a flying saucer. The design really consisted of using the circular planform to hold airfoil blades along the perimeter in two counter rotating rings to lift the craft vertically. Once airborne, these short blade sections would not be a hindrance to horizontal flight the way full sized helicopter blades are. While he did build working models and mock-ups of his design, he never acquired the funding to build a full sized version. The situation apparently weighed heavily upon him as he and his wife committed suicide.

     The Weygers Discopter is another idea that was presented with much art by its inventor, Alexander Weyger. The basic premise was in essence to replace the open rotating blades of a helicopter with a set enclosed within a disk shaped fuselage (akin to the FW Rochen proposal), The smaller personal transport enclosed the passenger at the center of the disk. Plans for a commuter version show passengers enclosed in individual pods along the periphery of the disk. While never developed in his lifetime, he appears to have been happily involved in many other fulfilling projects in his life.
     One of the downsides of many of these designs when compared to helicopters is that they are very limited in their flight capacity due to engine failure (helicopters can parachute down with their rotors through a property known as "autorotation"). Paul Moller ameliorates this problem by using many cross-linked motors in his design so there is no catastrophe due to a single engine failure. He is perhaps one of the more famous designers of personal flying saucers. This is because he has frequently been mentioned in media as the creator of a future flying car. His designs use multiple ducted fans to generate lift. While his Skycar design is not saucer shaped, he has tried out a variety of his ideas using a series of saucer like prototype craft culminating in his current M200 Neuera craft. Moller International has continued to develop these machines for over 30 years and may yet enter the mass market.
     Airship industries which created a market for lighter than air travel commercially in the 80s with their Skyship blimps initially produced a saucer shape airship (rigid?) designed to minimize turning moments on the craft caused by cross-winds. In the end the company went on to a series of more conventional blimps having made no more than a scale flying model version of the ship. Pictures of the original saucer skyship model frequents many UFO pages out there on the web.

Lightships

The light ship may perhaps be the closest we can get to flying space saucers with current technology. The idea is to use the shape as a focusing mirror in some designs to focus the light energy of a laser to superheat the air and thus propel the aircraft in a very rapid series of bursts. Models have been flown successfully and it does present a theoretical model for a ship that can attain very high velocities without having to carry it's own fuel. The shape has also been considered as a shape that can receive transmitted microwave energy. This energy can be used similarly to superheat air and thus achieve extremely high velocities. While they couldn't make do without using some reaction mass for the last part of the journey outside the atmosphere, they can make use of the beamed energy to heat it potentially making them extremely efficient orbital boosters.

Links and Resources

Many are the same from the last post, but in addition, here's a few more

• Tail-Sitter VTOL projects, sometimes referred to as "pogos" including the infamous Coleoptere
• The US Army's VZ series which included various flying platforms
• Henri Coanda information page at Florida International University
• The VZ-9 Avrocar can be visited at the US Air Force Museum in Dayton. Their website has the factsheet. 
• The Discopter site which continues to promote Weyger's craft
• Moller International, the corporate site for Moller's aircraft and engineering work.
• A short video excerpt which describes lightships very well on youtube.
• and yet again: Identified Flying Objects - An interesting set of articles and links to various saucer projects, particularly those tied to VTOL.
• and a link back to the previous Saucerful of Spaceships post