Propeller Simulation
Throughout the years, NLR and DNW have maintained first class testing of powered wind tunnel models. Recently, the development of the A400M aircraft has given NLR and DNW the impetus to push powered propeller testing to a higher level. Testing may involve powered models or the isolated propeller on a test rig.
Whereas DNW evolved their testing techniques, NLR further developed excellent capabilities in terms of CFC propeller blades, rotary balances, and very low-interference air supply and return lines ('air bridges').
Since NLR switched from metal to carbon fibre propeller blades in 1985, hundreds of blades have been made for dozens of propellers, ranging from 250 mm (10 inch) to roughly 1400 mm (55 inch) diameter. Many of those were for the APIAN, FLA, A400M series, for both Ratier Figeac and Dowty propellers.
Characteristics of NLR CFC blades:
- Solid carbon fibre reinforced structure with high geometric accuracy
- Virtually infinite fatigue life
- Blade natural frequencies tuned to lie outside operational RPM range
- Static 300% overload tests to cover static and dynamic strength (separate test blade)
- Continuous blade angle setting
- Sensor integration (unsteady pressure, strain gauges)
See a movie (about 2 min length) of the propeller fabrication process;
(You need an mpeg player and proper browser security settings to show the movie).
