Aerodynamics is one of the main fields of application for practical mathematics and the treatment of aerodynamic problems requires a thorough mathematical training. Whoever opens a modern book on aerodynamics will be surprised from the very beginning, that the phenomena within this very fugitive medium air may be expressed by formulas according to mathematical laws.

We must, however, never forget, that before a flow phenomenon can be mathematically analysed, physical reality must be understood by observation and experiment.

The mathematical treatment will always tend towards an approximate solution, as it is much too complicated to analyse a flow process exactly.

Investigations have been carried out in connection with the testing of a definite aeroplane type in order to ascertain the extent to which the safe take-off can be sufficiently ensured by prescribing certain practical requirements.

This led to inquiries into the question as to whether the qualities of the aeroplane in the take-off could be determined from individual tests, in such a way that it would be possible, from the results, to determine the take-off path when climbing in conformity with a definite previously established policy.

The present report consists of an analytical consideration of the safety in the take-off, which may be used as a practical guide for the predetermination of a safe take-off policy, and a means whereby the dimensions of an aerodrome, such as shall meet the rational requirements for a safe take-off (of a definite aeroplane type), can be determined.