Abstract
Rotor blades equipped with passively controlled tips were tested in an endurance test at the ECN rotor test facility. Upon inspection after 1200 hrs severe damage was observed. Consequently, it was decided to terminate the test. Fatigue loads were measured at low power, that is at almost free running conditions. Rainflow counting and frequency analysis were performed on the load measurements. The effects of cone angle, output power setpoint and constant speed operation on flapwise loads are discussed. Furthermore the load spectra at two radial stations are compared with design calculations. Results indicate that passive tips can effectively limit input power. if properly engineered. Tip pitch rotation introduces low frequency loads. At nominal power, less control effort is required and hence these loads are lower than at low power. At fixed speed operation, the flapwise loads are significantly lower than at variable speed with passive tip control. Comparison of measured load spectra with design calculations, shows that the design loads in the flapwise direction are conservative, especially near the tip. In the lead-lag direction at the blade root, measured load spectra are more severe than the design spectra. However, this proved to be of no practical consequence, since the fatigue
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Citation Formats
Cervenka, S, Dekker, J W.M., and Rieffe, H Ch.
Test of rotor blades with passively controlled tips. Phase 3: Endurance test.
Netherlands: N. p.,
1991.
Web.
Cervenka, S, Dekker, J W.M., & Rieffe, H Ch.
Test of rotor blades with passively controlled tips. Phase 3: Endurance test.
Netherlands.
Cervenka, S, Dekker, J W.M., and Rieffe, H Ch.
1991.
"Test of rotor blades with passively controlled tips. Phase 3: Endurance test."
Netherlands.
@misc{etde_10131791,
title = {Test of rotor blades with passively controlled tips. Phase 3: Endurance test}
author = {Cervenka, S, Dekker, J W.M., and Rieffe, H Ch}
abstractNote = {Rotor blades equipped with passively controlled tips were tested in an endurance test at the ECN rotor test facility. Upon inspection after 1200 hrs severe damage was observed. Consequently, it was decided to terminate the test. Fatigue loads were measured at low power, that is at almost free running conditions. Rainflow counting and frequency analysis were performed on the load measurements. The effects of cone angle, output power setpoint and constant speed operation on flapwise loads are discussed. Furthermore the load spectra at two radial stations are compared with design calculations. Results indicate that passive tips can effectively limit input power. if properly engineered. Tip pitch rotation introduces low frequency loads. At nominal power, less control effort is required and hence these loads are lower than at low power. At fixed speed operation, the flapwise loads are significantly lower than at variable speed with passive tip control. Comparison of measured load spectra with design calculations, shows that the design loads in the flapwise direction are conservative, especially near the tip. In the lead-lag direction at the blade root, measured load spectra are more severe than the design spectra. However, this proved to be of no practical consequence, since the fatigue behaviour of the rotor blade structure is determined by flapwise loads only. 33 figs., 12 tabs., 10 refs.}
place = {Netherlands}
year = {1991}
month = {Aug}
}
title = {Test of rotor blades with passively controlled tips. Phase 3: Endurance test}
author = {Cervenka, S, Dekker, J W.M., and Rieffe, H Ch}
abstractNote = {Rotor blades equipped with passively controlled tips were tested in an endurance test at the ECN rotor test facility. Upon inspection after 1200 hrs severe damage was observed. Consequently, it was decided to terminate the test. Fatigue loads were measured at low power, that is at almost free running conditions. Rainflow counting and frequency analysis were performed on the load measurements. The effects of cone angle, output power setpoint and constant speed operation on flapwise loads are discussed. Furthermore the load spectra at two radial stations are compared with design calculations. Results indicate that passive tips can effectively limit input power. if properly engineered. Tip pitch rotation introduces low frequency loads. At nominal power, less control effort is required and hence these loads are lower than at low power. At fixed speed operation, the flapwise loads are significantly lower than at variable speed with passive tip control. Comparison of measured load spectra with design calculations, shows that the design loads in the flapwise direction are conservative, especially near the tip. In the lead-lag direction at the blade root, measured load spectra are more severe than the design spectra. However, this proved to be of no practical consequence, since the fatigue behaviour of the rotor blade structure is determined by flapwise loads only. 33 figs., 12 tabs., 10 refs.}
place = {Netherlands}
year = {1991}
month = {Aug}
}