Unitsky String Technologies
31 October 2017
SkyWay vs skeptics
On passing the path from the origin up to the present time, SkyWay project answered most of the questions from skeptics. However, questions and complaints remained. It will always be this way. Planes fly, but many continue to say "planes crash". Man has conquered space, but it comes to such limit that some people claim - "it's a myth, the Earth is flat". From the theoretical point of view, these objections might make some sense. From the practical viewpoint - they are insignificant. Today, when SkyWay is already undergoing acceptance testing of the system's key elements, the project is ready to answer all the questions. For a start, we have selected some of the sane criticisms and give our answers. As an epigraph, here is a phrase attributed to J. Swift, one of the wittiest people:
"When a genius appears in the world, you can recognize him at least by the fact that all the thickheads unite in the fight against him."
"They have built not what they had declared earlier. The experimental tracks in EcoTechnoPark lack the main components of SkyWay technology - concrete in the rails, strings, a rail head, etc., the sags on the route are too large, the transport is noisy..."
About 5,000 people attended the EcoFest, which was held on July 1, 2017 in EcoTechnoPark. Photography and videography on-site of the demonstration and certification center were not forbidden, anyone could examine the tiniest details of the elements of tracks, anchor and intermediate supports, turnouts and make sure that everything is in their places in SkyWay. In addition, the main construction stages were described in detail by the news service of the Company. All the discussions regarding the lack of concrete and strings inside the rail do not have a real basis and are only the product of network commentators' imagination.
The sags of track structure at the section of the super-light urban route fully meet the design specifications. The string rail has different levels of rigidity depending on its design version (flexible, semi-rigid and rigid) and different degrees of tension on steel wire-strings, as well as the steel body, which determines the sag value on the track structure. SkyWay professionals have tested various operation modes of experimental tracks, in which the degree of string tension varied, therefore, the sag value at the string rail did not remain static, it had some changes. Now the sag value of the string rails on all tested route sections ensures compliance of vehicle movement with the requirements to comfort of passenger transportation.
Railhead. String rail can be manufactured in various versions, depending on the specific loads and operating conditions, including those with a steel head welded to its body, and without it. A steel head should not be considered like a separate element of the structure - in the first place a railhead is a flat steel surface (plane), on which a steel wheel is resting and rolling.
Since wear resistant and high strength types of steel are used for the construction of experimental tracks in EcoTechnoPark, arrangement of an additional welded steel head at this stage is not considered reasonable - this will have no effect except the increased cost. EcoTechnoPark, where SkyWay tracks are built is a testing and demonstration center. The loads on the track structure are here lower than in the structures, operated in commercial transportations. Traffic runs are rare here, therefore the wear of the track structure would be negligible. The cost of installation of a railhead as a separate element of string systems at the current stage of development is impractical. The primary task is to demonstrate the efficiency of such systems, in which pre-stressed elements (strings) are the overpass, rail, steel cables inside the rail and, to a certain extent, the concrete filler of the rail.
The noise level of SkyWay rolling stock is lower than that of such a popular mode of public transport, as the tram. The work to reduce the "noise emission" continues, rolling stock is becoming quieter and quieter.
"SkyWay technology looks very similar in its exterior to M?ller's Airbus, which was built in Germany in the 70s, however, it did not become popular in the market of transport services. If the similar technology was not needed, why SkyWay expects to be successful?"
Indeed, suspended monorail roads for passenger traffic have long been known and Anatoly Yunitskiy is not the first who proposed that trestle mode of transport. An elevated transport system in the city of Wuppertal was launched into operation on March 1, 1901. The suspended elevated system OPNV-Aerobus by a Swiss engineer Gerhard Muller can be called externally similar to one of the embodiments of Yunitskiy's suspended urban transport complex. However, they are similar in the exterior only (a wheel is rolling on the rail, but not on the cable): a detailed study of these systems reveals a number of significant design differences. Anatoly Yunitskiy has greatly improved elevated transportation, has created a system optimal from the viewpoint of the laws of physics. SkyWay distinguishes from Muller's system by at least the following features:
The material used to manufacture OPNV-Aerobus track structure is an aluminum alloy ("avial"), in SkyWay it is steel. This difference is one of key features: steel, compared to aluminum alloy, is a stronger and more plastic material with a lower coefficient of thermal expansion and higher limit of tension strength. Moreover, the production of steel structures is much less costly as opposed to aluminum.
The speed of movement of vehicles in SkyWay system is up to 500 km/h, in Muller's system - 35 km/h. Muller has implemented only one version of the track structure - a lightweight sagging one that is supported with a rope. Anatoly Yunitskiy has turned down this scheme - a lightweight track structure on spans of up to 5-km length will be self-bearing and does not need any support on the span. In addition, Anatoly Yunitskiy has implemented two more types of a string-rail overpass: with a semi-rigid rail and a rigid rail - a string truss that will allow to achieve speeds of 500 km/h.
Aerodynamics. The carriages of Muller's transport system did not have an aerodynamic shape. This trait may initially seem insignificant, because Aerobus rolling stock was moving at speeds up to 40 km/h. However, if we are speaking about high-speed traffic (from 150 to 500 km/h in Yunitskiy's system), in this case, up to 90% (or more) energy consumption will be spent on air "repulsion". The aerodynamic coefficient Cx in SkyWay is 7-8 times lower than in Muller's system. At high-speed motion, a unibus will need a less powerful motor by the same number of times.
Design of chassis. The use of the rolling pair "cylindrical steel wheel - flat steel railhead" in SkyWay provides several times less resistance to wheel rolling and much more durable track unlike that of Muller's aluminum rail with the railway-type wheel bearing on the railhead.
The total material consumption of Muller's system is markedly more compared to SkyWay. Moreover, the aluminum alloy used to manufacture the elements of Muller's track structure are lighter, but much more expensive to produce in comparison to steel.
Design of the track structure. In Muller's transport system the rail was suspended to a pre-stressed load-bearing cable of 52-mm diameter, which, in its turn, was suspended on pylons, similar to the design of suspension bridges (one of the most famous is the "Golden Gate" in San Francisco). In string transport systems the pre-stressed steel elements ("strings") are inserted inside the rail box that allows to create lightweight and durable constructions with a much smaller amount of financial expenses for construction and operation.
The differences between Muller's Airbus and SkyWay transport are as fundamental as those between modern cars and the Ford Model T from the beginning of the century: technologies have gone far ahead, and now the embodiment of the idea of "second level" transportation is much better designed and adapted to modern conditions. In fact, the only thing that unites these two transport systems is the idea of moving above the ground surface, but the practical engineering solutions are absolutely different.
These are not all the differences, but it's enough to "feel the difference". As for the lack of demand in the market for such transport systems, we can say the following: Muller's transport system was ahead of its time and too innovative, and the cities in the 70s did not experience such serious traffic problems, therefore the transport sector relied on the development of conventional and well-known types of public transport. The production volume of passenger cars increased by 2.8 times in 2012 compared to 1970. Accordingly, at present the transport problems of cities are much more serious than those that existed in 1975 and, to make sure of it, a resident of a large city will have only to look out of the window. Imagine SkyWay systems serving your transportation needs, and the doubts about the demand for these systems will disappear by themselves. The time for SkyWay did not come yesterday; it might pass away tomorrow, when teleportation systems will be invented. The time for SkyWay is today.
If this did not convince skeptics and ill-wishers about the differences in the systems of Muller and Yunitskiy, then let them answer the question: what is the difference between "Zaporozhets" and "Bugatti"? The same four round wheels on pneumatic tyres, the same round steering wheel, internal combustion engine, braking system, etc. If you find differences, please let us know...
We put an ellipsis at the end, because these are not all the questions. SkyWay news service will continue to monitor criticism and over time will give the answers to all sane and reasonable objections.
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