Summary and recent results from the NASA advanced high-speed propeller research program

Mitchell, G. A.; Mikkelson, D. C.

doi:10.2514/6.1982-1119

Cited by 16 publications

(6 citation statements)

References 11 publications

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“…Numerous studies by industry and NASA (which are summarized in Ref. 1) have shown that there is a potential 15 to 25 percent trip fuel savings with advanced turboprop powered aircraft compared to equivalent technology 1 turbofan powered systems for aircraft that cruise at Mach O.B. To achieve this fuel savings advantage, the propeller on this advanced turboprop would have to incorporate a number of unique design features that could enhance propeller performaQc~ and lower source noise at this high speed (2 ).…”

Section: Introductionmentioning

confidence: 99%

An analytical and experimental comparison of the flow field of an advanced swept turboprop

Neumann

Bober²,

Serafini³

et al. 1983

21st Aerospace Sciences Meeting

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An argon ion laser velocimeter (LV) with four beams has been used to measure the detailed flowfield of an advanced eight blade propeller with 4S· of tip sweep in the Lewis 8x6 Foot Supersonic Wind Tunnel. The propeller was tested at a Mach number of 0.8. The propeller operated at an advance ratio of 3.06 and a blade angle at the three-fourths radius of 60.5·. The test configuration was also analyzed using a curved lifting line analysis. A comparison of analysis results with LV data indicated blade blockage occurred near the nacelle. This resulted in a deceleration ahead of the blade and unsteady flow downstream. The LV data also indicated the presence of a shock wave emanating from the suction surface at a radius ratio of 0.79. The curved lifting line analysis qualitatively predicted the SR-3 propeller flow field. The comparison showed some differences between prediction and LV measurements. These aifferences can be attributed to phenomena not included in tne analysis such as viscous blade wakes, tip vortex rollup, blade blockage, and nacelle effects. Tne comparison has indicated underpredictions in the magnitude of the radial velocity jump across the blade. These differences lead to differences in blade loading and wake location. advance ratio, Vo/nD Mach number rotational speed, revolutions per second power, kW (ft-lb/sec) radius, cm (in.) blade tip radius, cm (in.) free-stream velOCity, m/sec (ft/sec) tip rotational velocity, m/sec (ft/sec) axial distance from nose of spinner, cm (in. ) ratio of total temperature to standard sea-level temperature of 518.7· R free-stream density, kg/m 3 (slugs/ft 3 )

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Section: Introductionmentioning

confidence: 99%

An analytical and experimental comparison of the flow field of an advanced swept turboprop

Neumann

Bober²,

Serafini³

et al. 1983

21st Aerospace Sciences Meeting

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“…Flights of medium range (1000-2000 nautical miles) with design cruise Mach numbers between 0.7 and 0.8 are predicted to achieve fuel savings of 10-20% [12,14,15]. Despite the lower or equal community noise levels compared with turbofans [12,14], a drawback of unducted propellers is increased cabin noise [16,17], in particular for flight Mach numbers ranging from 0.6 to 0.8. This noise is caused by an airborne contribution due to the unsteady pressure field induced by the rotating blades and the propeller-airframe interaction, and a structureborne contribution due to vibrations from the engines, propellers, and propeller-airframe interaction [18][19][20][21].…”

Section: Aerodynamic Performance and Static Stability Characteristics...mentioning

confidence: 99%

“…Despite successful reductions of cabin noise by employing various techniques [16,17,19,[22][23][24][25][26][27][28][29], the cabin noise levels of current turboprops are still several decibels higher compared with turbofan-driven aircraft [17,20,25,30,31]. This noise penalty is aggravated due to the tonal components of the noise spectrum, which are perceived by passengers as more annoying than broadband noise [17].…”

Section: Nomenclaturementioning

confidence: 99%

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Aerodynamic Performance and Static Stability Characteristics of Aircraft with Tail-Mounted Propellers

Arnhem

Vries

Sinnige

et al. 2022

Journal of Aircraft

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“…Propellers boast a distinct performance advantage over any other form of aircraft propulsion system up to Mach 0.8 [1]. Despite this, the mid to high velocity (Mach 0.6 to 0.8) civil aviation market has been largely dominated by turbofans.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of the effect of yaw angle on the inflow of a two-bladed propeller

Zarev

Green

2020

Aerospace Science and Technology

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An experimental investigation has been performed to measure the inflow of a two-bladed propeller. This is conducted over a range of advance ratios (J = 0.36 to 1.54) and yaw angles (γ = 0 to 20 • ) at a Reynolds number of Re ≈ 111000, based on the chord length and advancing blade resultant velocity at the 70% spanwise position.Drawing on experimental results, three major qualitative trends are observed, that characterise the axial induced inflow of inclined propellers: the formation of an approximately sinusoidal inflow trend around the azimuth featuring broad regions of increased and reduced inflow, an azimuthal phase shift of the trend from the advancing and retreating blade positions, and the dependencies of the inflow maxima, minima and phase shift on advance ratio, yaw angle and radial position. These are subsequently compared against two widely used assumptions for calculating the aerodynamic environment of inclined propellers; firstly, that inflow at each radial and azimuthal element is calculated using an axial approximation of the whole propeller disc operating within the same condition as that element, and secondly, uniform induced inflow across the entire propeller plane. The comparison demonstrates the limitations of said assumptions by highlighting their inability to account for components of the trailed and shed vortical systems of the propeller wake.

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Summary and recent results from the NASA advanced high-speed propeller research program

Cited by 16 publications

References 11 publications

An analytical and experimental comparison of the flow field of an advanced swept turboprop

An analytical and experimental comparison of the flow field of an advanced swept turboprop

Aerodynamic Performance and Static Stability Characteristics of Aircraft with Tail-Mounted Propellers

Experimental investigation of the effect of yaw angle on the inflow of a two-bladed propeller

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