Number
of wagons
15
Highest point of the Ferris wheel
64.75 m
above the ground
Diameter of the wheel
60.96 m
(= 200 engl. Feet)
Outer diameter of the wheel construction
55.78 m
Inner diameter of the wheel construction
49.68 m
Axle of the Ferris wheel
10.78 m long
0.5 m thick, 16.3 t heavy
Weight of the entire wheel assembly
244.85 t
Total weight of all iron structures
430.05 t
Speed
0.75 m/sec
= 2.7 km/h
An engineered masterpiece.
Oberbaurat Beck.
As early as 1937, engineer Friedrich Beck—after nearly 40 years of working with the Ferris wheel – wrote a technical description of the structure that has lost none of its fascination or relevance to this day.
At first, the municipal authorities in Vienna had reservations about what was, for that time, an extraordinarily bold project – the construction of a giant Ferris wheel. Only after Professor Eng. Johann Brick of the Vienna University of Technology, renowned for his work in bridge construction, had reviewed the calculations and submitted them to the municipal building authority the project was granted official approval.
A masterpiece of engineering.
Construction details.
In principle, the Ferris wheel can be seen as a bridge, structurally composed of two identical semicircles placed one above the other. These are suspended from the hubs of the main axle by 120 flexible cable spokes. However, during each rotation, only the portion of these 120 spokes located near the downward vertical plane actually bears the load.
The main axle of the Ferris wheel—manufactured by the steelworks W. Baedmore & Co. in Glasgow—is 10.9 meters long, has a diameter of 0.5 meters, and weighs 16.3 tons. It rotates within two open bearings mounted on the tops of four pylons each, transferring the entire weight of the wheel onto eight foundations.
Transporting the axle alone was a challenge: the wagon, pulled by 16 horses, sank into the soft ground of the Prater and had to be freed using lifting equipment. A specially reinforced track was then constructed to ensure the axle could be safely delivered to its final destination.
Step by Step to the Finished Wheel
The sophisticated structural engineering of the Ferris wheel
The pylons and the wheel were built without the use of scaffolding. Steam cranes with pivot arms, standing on three wooden towers which rose in height as construction work progressed, hauled the different parts of the iron structure upwards. The wheel was assembled in a self-supporting manner in that first of all a wheel segment was suspended from the hub of the large axis by means of cable spokes. Then a further segment was connected to the left and the right of it and secured to the hubs by the spokes. In this fashion, construction advanced. The wheel therefore supported itself during construction, the more so as the individual segments were connected to the hub of the large axis by the cable spokes.
The outer circumference of the rim is connected to the inside by radial latticework and by two diagonal tension rods. The western rim facing the city is also rigidly connected to the eastern rim facing the Prater at a distance of 6 meters by means of latticework and tension rods. Between said radials, the structure connecting the outer circumference with the inner circumference, a wagon is suspended at each joint between two wheel segments. Each wagon is 5.4 meters long, 2.45 meters wide and 2.65 meters high; they are suspended on a steel axis so that the floor remains in a horizontal position even as the wheel rotates.
So much for Mr. Beck’s account from 1937. The inner spokes which secure the circumference rim to the axis consist of steel wire ropes with a diameter of 10 cm and grommets at the ends. Of the 120 spokes which are mounted at the suspension points of the cabins, 60 are fitted at right angles to the axis, while the remainder are diagonal, in order to provide extra resistance against wind pressure.
The load-bearing structure of the wheel
Rim, spokes, and drive system in perfect interaction
The wheel rim consists of steel plates and brackets, whereby the brackets face outward and are connected to the circumference opposite. As a result, the circumference forms a girder to which the inside spokes referred to earlier are attached. The 6.35 meter long outer spokes are riveted to the inner and outer circumference cover plates by latticework.
The outer circumference of the wheel is also made of U-shaped girders, namely two parallel girders which are connected both to each other and to the inner circumference of the wheel rim by flat steel supports. The circumference spokes form the extension of the steel wire rope spokes and consist of riveted beams, which are directly attached to the two concentric wheel rim rings.
The Giant Ferris Wheel is powered by two traction cables which permit the transmission of the necessary torque through friction pads on the outer sides of the wheel rim. The two drive motors work on a single shaft in order to guarantee synchronization of the two traction cables. The further transmission of power to the rope drive is carried out over pulleys and a two-stage transmission.
Engineering
built to Last
System, maintenance, and safety of the Vienna Giant Ferris Wheel
The slipring motors from 1984 produce 15 kilowatts and rotate at a speed of 720 revolutions per minute.
In 1988 the cogwheels from the post-war years and the complete drive propulsion system were replaced.
In 1997 and 1999 the Giant Ferris Wheel was completely repainted. After extensive sand blasting work, 200 tons of old paint and sand were removed and only 4 tons of new anti-corrosion paint applied as protection against wind and weather for the decades to come.
Even those visitors who are not particularly interested in technical details often ask what would happen in the event of a power cut. We can reassure Giant Ferris Wheel passengers: we have an emergency generator which is permanently monitored and which is able to guarantee standby operations at any time.