The FLYWAY Beams

Shrink to patient: - Look mr. senator, I can´t cure your problems if you keep answering "no comments" to all my questions!

he beams are the arteries of the system, in a manner of speaking. The general theory of designing beams (from SwedeTracks point of view) has been detailed on a separate page. This page will be devoted to the FLYWAY® beam design. The FLYWAY® design will mainly follow the commonly accepted pattern, with a view to either establish or adopt a common interface standard for beam design. As stated elsewhere, it would be highly desirable if, in the future, beam networks from different manufacturers had common interfaces, so that they could be interconnected, and beamcars thus being able to travel from one network to another, as is possible with regular railway services.		This is a rather technical page. We will deal with: General considerations Beam dimensions Manufacture and assembly of straight beams Manufacture and assembly of curved beams Manufacture and assembly of sloping beams Special beam elements Sloping beams and shunts are dealth with on other webpages.

here is no rule that says that beams for this kind of purpose have to have a rectangular cross-section. Other shapes have been proposed. But as long as other shapes are not strongly motivated by some special circumstance, the rectangular cross-section is the most straight-forward design. Figure 1:3 What, then, about material for the beams? One could use straight steel, alloyed steel, alloyed aluminum, glass-fiber and even glass, if one wants to. The important criteria for SwedeTrack when choosing a suitable beam-material are that it should be: Strong, in relation to its cost Durable and maintenance-free Resilient against weather, fire, earthquakes and willful damage Unpenetrable for electro-magnetic waves. The last condition alone mandated that we had to choose steel or aluminum. Comparing those 2, steel won out. With proper painting and/or zinc plating for corrosion protection, steel would be the material of choice. By roll forming sheet metal during the manufacturing process, one gets the desired shape of the parts, which are then welded together.

Air Compression and Aerodynamic Drag The propulsion car inside the beam would be subjected to air compression in front and aerodynamic drag behind it, when moving. The compressed air in front and the thin air behind both the cabin and the propulsion car (as illustrated above) have a braking effect on the vehicle. This effect only increases with speed. The solutions are, of course, to: Giving the propulsion car as small cross-sectional area as possible Making the cabin small, and giving it an aerodynamic design Giving the air inside the beam as much chance as possible to move out of the way. Addressing the third issue here, the slit at the bottom of the beam should be rather broad. FLYWAY, as opposed to most other PRT-systems, proposes to use elevators on its vehicles, which might require broader slits than would otherwise be needed. In addition, beam segments will need space for lateral movements, and this will be provided for with a few centimeters´ gap between beam segments. This gap will be covered with casings (se illustration further down) wich will be so designed that they lets air out and in through both sides when a vehicle passes by.

	ne can always use other criteria to dimension the beams, but it is convenient, considering the standardized width of of propulsion cars, to only vary the height of the beams to accomodate various loads. The beams that SwedeTrack have been calculating with have the following measurements and outer dimensions: 2 sizes with varying heights: a) Width x Height = 0.80 x 0.60 meters for loads up to 2 tons b) Width x Height = 0.80 x 1.13 meters for cargoes up to 7 tons
	On the other hand, using the same height for all beams means that beam supports need not be adjusted vertically when altering beamsizes on a route. Thus: 3 sizes with varying widths: a) Width x Height = 0.50 x 0.90 meters for loads up to 0.7 tons b) Width x Height = 0.70 x 0.90 meters for loads up to 2 tons c) Width x Height = 0.90 x 0.90 meters for cargoes up to 7 tons Alternatively: a) Width x Height = 0.50 x 1.10 meters for loads up to 1.0 tons b) Width x Height = 0.70 x 1.10 meters for loads up to 2.5 tons c) Width x Height = 0.90 x 1.10 meters for cargoes up to 7.5 tons
	Other dimensions under considerations are: Span, meters Weight, Kg/meter Width, mm Depth, mm 40 119 701 978 50 235 711 1,220 60 259 711 1,575

he pre-fabrication of straight beam elements should be quite straight-forward. The top, the sides and the runways are manufactured in 10 meter length segments (or thereabouts). In addition, som lenths would have to be custom-made to meet specific requirements. These parts are then welded together, as shown to the right. For strength, "ribs" would then have to be added at regular intervals. This is further described on a separate page. Figure 3:1 Figure 3:2 The beams should be prefabricated with an upward bent (so-called "camber", which is shown exaggerated in the figure above), to compensate for the beam´s own weight and for the downward stress of passing beamcars. One or two flanges near the bottom slit would fill the same function; to stiffen the beam. Some sort of casing or inner lap, welded onto the end of one of the beam segments, might also be needed where beam segments are joined, both to take up movements due to heat expansion, and to allow the beams to move laterally in conjunction with moving vertically when beamcars pass through. This lap, shown at right, would protect the beams´ interiors, but would at the same time let some air pass out and in (as noted above, under "general considerations").

Figure 3:3

aced with the task in the illustration above, of connecting beams A and B, where the beams are at a certain distance and at right angles to each other, one has 4 general choices of going about it. Naturally, the terrain and other circumstances might force the designers to adopt one of the choces. Going around a street corner, for instance, one would be stuck with the first solution. But generally, having free choice, one could either: Use straight beam elements as much as possible Allow a little higher speed by using two 45-degree curves instead of one 90-degree Allow still higher speed by putting more knees between straight beam elements of fixed, pre-fabricated lengths Provide for the smoothest possible ride by curving the beam the whole distance.

If one were to satisfy oneself with the first three choices, one could supplement straight beams with knee-elements, which might be fixed, custom-made at certain angles, or adjustable knees. To be certain, those knee-elements are needed at tight spots, such as street corners and at station areas. But it would be poor service not to include long, custom-made curved beam-elements as integrated parts of the beam network. As with straight beam sections, these curved ones would be custom-designed for each installation site and manufactured by roll forming sheet steel. These elements are then welded together before being shipped in sections to the construction site.

he sloping beams do not consist of vertically curved beams. they are straight or horisontally curved beam sections that are joined to ordinary, level, beam sections with the aid of vertically bent knee-sections. This knee could be custom-made, or come in a few standardized angles.	Figure 5.1

Figure 6.1 here are 2 types of beam elements that need to be added, to make the assembly kit complete. One type is the shunt, shown in figure 6.1, which only comes in two shapes, and in suitable sizes to fit the beam being erected.	The angle a is always the same; 12 degrees. This angle enables the beamcars to keep a reasonable cruising speed when switching into either leg in picture 1, and when travelling straight ahead in picture 2. Whether the car has to slow down or not when switching into the right leg in picture 2 depends of course on its´ speed. The other type is the knee shown in figure 6.2. Knees are needed, to get around street corners, to have stations with many berths, etc. The FLYWAY concept assumes that an inner radius of curvature of 250 centimeters will be sufficient. The smallest knee elements will thus constitute 1/16:th of such a circle, and will thus be custom-made to fit the need at the construction site, at any angle between 0 and 22.5 degrees of angle. 4 such elements, about 1 meter in length, would thus suffice to negotiate a street corner. If the situation requires knees with angles greater than 22.5 degrees, the required number of such elements would be assembled into one element at the factory, before delivery. SwedeTrack at present experiments with a more flexible concept for these knees. They need to be adjustible both vertically and horizontally.	Figure 6.2