Abstract
Replacing rigid pitch links on rotorcraft with fluidic pitch links changes the blade torsional impedance. At low frequency, the blade must have high impedance to pass through the pilot's collective and cyclic commands to control the aircraft. At higher frequencies, however, the pitch link impedance can be tuned to change the blade pitching response to higher-harmonic loads. Active blade control to produce higher-harmonic pitch motions has been shown to reduce hub loads and increase rotor efficiency. This paper investigates whether fluidic pitch links can passively provide these benefits. An analytical model of a fluidic pitch link is derived and incorporated into a rotor aeroelastic simulation for a rotor similar to that of the UH-60. Eighty-one simulations with varied fluidic pitch link parameters demonstrate that their impedance can be tailored to reduce rotor power and all six hub forces and moments. While no impedance was found that simultaneously reduced all components, the results include cases with reductions in the lateral 4/rev hub force of up to 91% and 4/rev hub pitching moment of up to 67%, and main-rotor power of up to 5%.
| Original language | English (US) |
|---|---|
| Title of host publication | American Helicopter Society International - 5th Decennial AHS Aeromechanics Specialists' Conference 2014: Current Challenges and Future Directions in Rotorcraft Aeromechanics |
| Publisher | American Helicopter Society International |
| Pages | 273-281 |
| Number of pages | 9 |
| ISBN (Electronic) | 9781634391788 |
| State | Published - 2014 |
| Event | 5th Decennial AHS Aeromechanics Specialists' Conference 2014: Current Challenges and Future Directions in Rotorcraft Aeromechanics - San Francisco, United States Duration: Jan 22 2014 → Jan 24 2014 |
Other
| Other | 5th Decennial AHS Aeromechanics Specialists' Conference 2014: Current Challenges and Future Directions in Rotorcraft Aeromechanics |
|---|---|
| Country | United States |
| City | San Francisco |
| Period | 1/22/14 → 1/24/14 |
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All Science Journal Classification (ASJC) codes
- Aerospace Engineering
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Impedance tailored fluidic pitch links for passive hub vibration control and improved rotor efficiency. / Scarborough, Lloyd H.; Rahn, Christopher D.; Smith, Edward; Koudela, Kevin L.; Jolly, Mark R.
American Helicopter Society International - 5th Decennial AHS Aeromechanics Specialists' Conference 2014: Current Challenges and Future Directions in Rotorcraft Aeromechanics. American Helicopter Society International, 2014. p. 273-281.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
TY - GEN
T1 - Impedance tailored fluidic pitch links for passive hub vibration control and improved rotor efficiency
AU - Scarborough, Lloyd H.
AU - Rahn, Christopher D.
AU - Smith, Edward
AU - Koudela, Kevin L.
AU - Jolly, Mark R.
PY - 2014
Y1 - 2014
N2 - Replacing rigid pitch links on rotorcraft with fluidic pitch links changes the blade torsional impedance. At low frequency, the blade must have high impedance to pass through the pilot's collective and cyclic commands to control the aircraft. At higher frequencies, however, the pitch link impedance can be tuned to change the blade pitching response to higher-harmonic loads. Active blade control to produce higher-harmonic pitch motions has been shown to reduce hub loads and increase rotor efficiency. This paper investigates whether fluidic pitch links can passively provide these benefits. An analytical model of a fluidic pitch link is derived and incorporated into a rotor aeroelastic simulation for a rotor similar to that of the UH-60. Eighty-one simulations with varied fluidic pitch link parameters demonstrate that their impedance can be tailored to reduce rotor power and all six hub forces and moments. While no impedance was found that simultaneously reduced all components, the results include cases with reductions in the lateral 4/rev hub force of up to 91% and 4/rev hub pitching moment of up to 67%, and main-rotor power of up to 5%.
AB - Replacing rigid pitch links on rotorcraft with fluidic pitch links changes the blade torsional impedance. At low frequency, the blade must have high impedance to pass through the pilot's collective and cyclic commands to control the aircraft. At higher frequencies, however, the pitch link impedance can be tuned to change the blade pitching response to higher-harmonic loads. Active blade control to produce higher-harmonic pitch motions has been shown to reduce hub loads and increase rotor efficiency. This paper investigates whether fluidic pitch links can passively provide these benefits. An analytical model of a fluidic pitch link is derived and incorporated into a rotor aeroelastic simulation for a rotor similar to that of the UH-60. Eighty-one simulations with varied fluidic pitch link parameters demonstrate that their impedance can be tailored to reduce rotor power and all six hub forces and moments. While no impedance was found that simultaneously reduced all components, the results include cases with reductions in the lateral 4/rev hub force of up to 91% and 4/rev hub pitching moment of up to 67%, and main-rotor power of up to 5%.
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UR - http://www.scopus.com/inward/citedby.url?scp=84911376812&partnerID=8YFLogxK
M3 - Conference contribution
SP - 273
EP - 281
BT - American Helicopter Society International - 5th Decennial AHS Aeromechanics Specialists' Conference 2014: Current Challenges and Future Directions in Rotorcraft Aeromechanics
PB - American Helicopter Society International
ER -