Engineering Papers⌕ Search

Engineering topics

Schrenk, Martin

Publications and source records attributed to Schrenk, Martin.

8 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1934

Aerodynamic principles of the direct lifting propeller

The purpose of this report is to make the complicated processes on the direct-lift propeller amenable to analysis and observation. This is accomplished by placing the physical phenomena, starting with the most elementary process, in the foreground, while limiting the mathematical treatment to the most essential in view of the fundamental defects of the theorems. Comparison with model experiments supplements and corroborates the theoretical results.

Schrenk, Martin↗
NASA NTRS1933

Take-off and propeller thrust

As a result of previous reports, it was endeavored to obtain, along with the truest possible comprehension of the course of thrust, a complete, simple and clear formula for the whole take-off distance up to a certain altitude, which shall give the correct relative weight to all the factors.

Schrenk, Martin↗
NASA NTRS1932

The mutual action of airplane body and power plant

The present report concerns the development of general propeller performance and r.p.m. curves which, combined with the general curve of the power required for level flight, presents a complete picture of the performance.

Schrenk, Martin↗
NASA NTRS1930

Structural details of German light airplanes

This report presents a review of German light airplane construction. Some of the topics discussed include: engines, fuselages, wings, landing gear, and other mechanical parts.

Schrenk, Martin↗
NASA NTRS1930

Measurement of profile drag on an airplane in flight by the momentum method. Part II

The purpose of this section is to survey the present status of scientific knowledge of the causes which produce drag, in order, if possible, to establish the relation between the individual results and the actual phenomena which demonstrate the fundamental importance of surface conditions. A discussion of the boundary layer is followed by: relations between frictional and form drag, application to profile-drag measurements, and different kinds of roughness. High-pressure wind tunnel tests are discussed along with roughness and maximum lift.

Schrenk, Martin↗
NASA NTRS1928

Calculation of Airplane Performances Without the Aid of Polar Diagrams

For good profiles the profile-drag coefficient is almost constant in the whole range which comes into consideration for practical flight. This is manifest in the consideration of the Gottingen airfoil tests and is confirmed by the investigations of the writer (measurements of the profile drag during flight by the Betz method), concerning which a detailed report will soon be published. The following deductions proceed from this fact. The formulas developed on the assumptions of a constant profile-drag coefficient afford an extensive insight into the influences exerted on flight performances by the structure of the airplane.

FORMULAS - PERFORMANCE↗
NASA NTRS1928

A few more mechanical-flight formulas without the aid of polar diagrams

The reliability of the assumption of a parabolic shape of the polar curve is investigated and found satisfactory for all practical purposes. It is further shown that the aerodynamically best possible or "ideal" airplane is produced on this assumption. Lastly, detailed suggestions are given on the possibilities of application of this method of calculation. It especially simplifies the design and evaluation of structural changes and the determination of the limits of technical possibilities. The present report deals only with the relations of the airfoils. The mutual action of the airfoils, engine and propeller will be treated in a subsequent report.

FORMULAS - PERFORMANCE↗