@Felix: the total flightweight of the system is 3400g.
@Simon: you are right, the battery weight 2 kg. The transmitter used was Graupner MX-16, receiver GR-12.
@Gerard: I saw that video, Ferdinands result is just insane. But some people say that flying over the roof above the buildings wall is a kind of trick to extend the flight. Not sure how much profit does it give, that's why I just flew over flat meadow in a very calm weather.
Regards motors, that's right, I lowered the KV number to match the 6S and 17 zoll configuration.
@Eduardo: the price of the system was also important. Well, the 28 inch props and matching motors were "a bit" expensive for my budget.