Nordex Gives Wings

The First Test of Crane Balloon in Neuhardenberg

A Report by Dr. Dirk Spaltmann

(LifterNews Sep 2008)

A video you´ll find in our video library (see link on top).

Expectation

Getting up early on an especially requested vacation day normally does not belong to my favourite habits. But on December 11th, 2007 everything was different. I even awoke before the alarm clock rung. It must have been because I had an appointment with Christoph von Kessel at seven o’clock. Christoph is one of the chief developers of CargoLifter and the chance to discuss exciting issues with him arranged it so that many things took less time than usual.
On this day everything should be far from usual. The task force had been convened in order to do the decisive testing in Neuhardenberg. Would the weather be on our side? On the first try in November the weather was on our side, but not the supplier for hydrogen. He had not delivered a plain adapter unit and was not able to deliver it before the fl ight permission expired. These times nothing had been left to chance. Everything was at its place, revised again and again. But what about the weather, would the weather be steady? On the way to Neuhardenberg it seemed not to get light at all. Then it even began to rain. While I was flooring the accelerator Christoph was
on the phone constantly. ‚Tony, how’s the weather?’, Christoph wanted to know. It drizzled lightly, but besides that the view was okay, and the wind was still acceptable. The balloon had already been laid out. One was only waiting for the boss to come. Christoph addressed them "Please begin, we will be there with you any minute!" Just a few short and precise instructions to add. No signs for tension at all. Tony Eden, leader of the task force, already was on site, as well as the whole team of Richard Martin. Since four o’clock they had been on duty, providing pick-up trucks, converting and assembling winches, bringing the balloon to Neuhardenberg. This time the hydrogen was already there, and the rising permission granted.

It begins

It took nearly 1½ hours until the balloon was filled. The first result of the test was already visible: the connection tube had to be considerably thicker to fill a 40m-Balloon in an acceptable time frame. Totally relaxed a team member leaned against the pressure tanks for almost 300 m³ hydrogen with the outlet fully opened. In the meantime the balloon was completely filled and clinged at a winch. Forces were measured, density controlled and started to work off the testing program point
by point. Now it was the turn for simulating great wind forces. This was something for me. Together with four other team members we pulled on a rope and tried to tow the balloon at 45°. This was not so simple and would signify clearly more than wind force 5 indeed. By command we let go the balloon. The oscillation altitude would help Dr. Martin Kraska to optimize the parameters in his simulation program. The most astonishing for me was the suspension of the actual load. It made sure that the load
was as good as not moving in spite of the oscillating balloon.

The thing with the wing

Now it was time for the test with the wing. A prestigious German manufacturer for wind turbines, the company Nordex, had made a true to scale rotor blade exclusively for the test with our balloon. If this test was successful we would be able to move real rotor blades with a 40m-balloon. This was the baptism of fire for the steering system developed by Richard Martin and his team – and it succeeded. The faces lighted up and you were able to see an adventuresome sparkle in the eyes of the team workers. Would we get one better? In the meantime Mirko Hörmann, managing director of CL KGaA arrived at the proving grounds, too. For a moment he argued with Christoph and then it was clear, we would challenge it. The winches were fixed at vehicles in particular. This should allow simulating driving on serpentine roads – with balloon in tow together with the rotor blade mock up! As if taken for granted the vehicles started to move and conducted the majestically gliding balloon with its precious load with
surprisingly facility. It was done, the evidence was proved, and the target of the testing achieved – the proof of concept! And I was a witness.
It only remains for me to mention that the balloon deflated within five minutes from opening the outlet. Handled properly the hydrogen conducted completely unproblematic. Until late at night the build-up team was occupied with removing all traces of the test, hauling in the balloon, dismantling the vehicles and of course first reports had to be written.

So after all on our passage back I had the chance to discuss things with Christoph. A beautiful day!

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