Feasibility study to develop a Mach-scaled swashplateless rotor model

Kim, Jongmin; Koratkar, Nikhil

doi:10.1088/0964-1726/14/1/008

Cited by 2 publications

(3 citation statements)

References 10 publications

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“…Some researchers have started looking at the feasibility of a swashplateless helicopter rotor in recent years (Omistron, 2001; Shen and Chopra, 2004; Kim and Koratkar, 2005; Shen et al , 2006). Most works in this area propose the use of on‐blade flaps for primary control, as an alternative to the swashplateless rotor concept.…”

Section: Introductionmentioning

confidence: 99%

“…A flap length of 22 percent of the blade radius, flap chord ratio of 0.30, overhang length of 15 percent chord and location around 83 percent was found to be optimal for the rotor considered in this study. In another work, Kim and Koratkar (2005) used an analytical model of an induced shear tube actuator to explore the feasibility of using this actuator for a Mach scale wind tunnel model. The study showed that for present piezoelectric materials (0.15 percent maximum strain) the swashplateless rotor was only feasible for advance ratios ( μ , non‐dimensional forward speed) below 0.1 and blade torsional frequencies below 1.8/rev.…”

Section: Introductionmentioning

confidence: 99%

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Optimal location of centre of gravity for swashplateless helicopter UAV and MAV

Ganguli

Jehnert

Wolfram

et al. 2007

Aircraft Engineering and Aerospace Technology

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PurposeTo investigate the use of centre of gravity location on reducing cyclic pitch control for helicopter UAV's (unmanned air vehicles) and MAV's (micro air vehicles). Low cyclic pitch is a necessity to implement the swashplateless rotor concept using trailing edge flaps or active twist using current generation low authority piezoceramic actuators.Design/methodology/approachAn aeroelastic analysis of the helicopter rotor with elastic blades is used to perform parametric and sensitivity studies of the effects of longitudinal and lateral center of gravity (cg) movements on the main rotor cyclic pitch. An optimization approach is then used to find cg locations which reduce the cyclic pitch at a given forward speed.FindingsIt is found that the longitudinal cyclic pitch and lateral cyclic pitch can be driven to zero at a given forward speed by shifting the cg forward and to the port side, respectively. There also exist pairs of numbers for the longitudinal and lateral cg locations which drive both the cyclic pitch components to zero at a given forward speed. Based on these results, a compromise optimal cg location is obtained such that the cyclic pitch is bounded within ±5° for a BO105 helicopter rotor.Originality/valueThe reduction in the cyclic pitch due to helicopter cg location is found to significantly reduce the maximum magnitudes of the control angles in flight, facilitating the swashplateless rotor concept. In addition, the existence of cg locations which drive the cyclic pitches to zero allows for the use of active cg movement as a way to replace the cyclic pitch control for helicopter MAV's.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimal location of centre of gravity for swashplateless helicopter UAV and MAV

Ganguli

Jehnert

Wolfram

et al. 2007

Aircraft Engineering and Aerospace Technology

View full text Add to dashboard Cite

show abstract

“…The first two approaches are the trailing-edge flap concept (9)(10) and the active twist rotor concept (11) . As mentioned by Kim and Koratkar (11) , the active twist concept with current day piezoelectric materials allows a swashplateless rotor only for advance ratios below 0•15 even if the torsion frequency is reduced to 1•8/rev. Among these two approaches, the trailing-edge flap approach appears to be more feasible using current smart material technology.…”

Section: Introductionmentioning

confidence: 99%

Survivability of helicopter with individual blade primary control failure

et al. 2007

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The effect of actuator damage on a helicopter rotor with an IBC based primary control system is studied. Such a system eliminates the swashplate and can be accomplished by trailing-edge flaps, active twist or full authority IBC, especially with smart material actuators. Damage to the collective, longitudinal and lateral cyclic are simulated for one blade, both individually and in combinations ranging from partial damage to complete failure. Numerical results are obtained using a dissimilar blade aeroelastic analysis based on finite elements in space and time for hover and forward speed conditions. It is found that the helicopter can be trimmed for all cases with all three controls having failed on the blade with actuator damage thereby showing that the IBC actuated rotor can survive an actuator failure and can be reconfigured by the pilot using the controls on the other blades. However, in case the collective fails and the longitudinal cyclic is present, there are problems in achieving trim at high damage levels at high forward speeds. Physical explanations of this phenomenon are given. The response (especially flap) for the damaged rotor blades can become high and 1/rev and 2/rev are transmitted by the reconfigured rotor to the hub. Results show that IBC based primary controls provide redundancy which can improve the survivability of a helicopter in case of actuator failure in one blade.

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Feasibility study to develop a Mach-scaled swashplateless rotor model

Abstract: An analytic model was developed for the response and trim of a swashplateless controllable twist rotor featuring a piezoelectric induced-shear tube actuator. First, a parametric study was conducted to determine the sensitivity of the actuation requirements for primary rotor

Cited by 2 publications

References 10 publications

Optimal location of centre of gravity for swashplateless helicopter UAV and MAV

Optimal location of centre of gravity for swashplateless helicopter UAV and MAV

Survivability of helicopter with individual blade primary control failure

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