Propeller Design for a future QESTOL Aircraft in the BNF Project

Lenfers, Carsten

doi:10.2514/6.2012-3334

Cited by 12 publications

(8 citation statements)

References 5 publications

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“…With the required static thrust known from the preliminary aircraft design, an existing propeller [28] that was originally designed for a similar STOL research project was adapted to the present requirements. Hence, its diameter was reduced from D P 6 m to D P 5 m while increasing the shaft speed to keep a constant blade tip Mach number of Ma tip 0.75.…”

Section: B Propellermentioning

confidence: 99%

Aerodynamic Installation Effects of an Over-the-Wing Propeller on a High-Lift Configuration

Müller¹,

Heinze²,

Kožulović³

et al. 2014

Journal of Aircraft

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Preliminary design studies indicate that a cruise-efficient short takeoff and landing aircraft has enhanced takeoff performance at competitive direct operating costs when using high-speed propellers in combination with internally blown flaps. The original tractor configuration is compared to an over-the-wing propeller, which allows for noise shielding. An additional geometry with partially embedded rotor similar to a channel wing is considered to increase the beneficial interaction. This paper shows the aerodynamic integration effects with a focus on climb performance and provides an assessment of the three aforementioned configurations for a simplified wing segment at takeoff conditions. Steady Reynolds-averaged Navier-Stokes simulations have been conducted using an actuator disk model and were evaluated based on the overall design. Interacting with the blown flap, the conventional tractor propeller induces large lift and drag increments due to the vectored sliptream. Although this effect is much smaller for an overthe-wing configuration, by halving the lift augmentation, the lift-to-drag ratio and the propulsive efficiency are considerably improved. Besides a moderate lift gain, the main advantage of a channel wing design is the location of the thrust vector close to the center of gravity resulting in a smaller nosedown pitching moment due to thrust. A disadvantage of over-the-wing propellers is the inhomogeneous inflow at higher velocity, which leads to oscillating blade loads and reduced efficiency.lift coefficient of aircraft C M;y = M y ∕q ∞ · S ref · MAC, pitching moment coefficient of aircraft C P;s = shaft power coefficient C T = 2 · T∕q ∞ · S ref , thrust coefficient of aircraft c = chord length of rectangular wing segment c d = section drag coefficient c l = section lift coefficient c m = section pitching moment coefficient c p = p − p ∞ ∕q ∞ , pressure coefficient D P = propeller diameter p = static pressure q ∞ = dynamic pressure of freestream S ref = wing area of reference aircraft s = semispan of rectangular wing segment T = thrust of one engine T inst = T − ΔD, installed thrust t∕t max = relative blade element thrust V ∞ = freestream velocity α = angle of attack α e = effective angle of attack at blade element β 75= propeller blade pitch angle (at 75% radius) η P = propeller efficiency η Pro = propulsive efficiency ρ ∞ = density of freestream Subscripts x,y,z = Cartesian coordinates

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Section: B Propellermentioning

confidence: 99%

Aerodynamic Installation Effects of an Over-the-Wing Propeller on a High-Lift Configuration

Müller¹,

Heinze²,

Kožulović³

et al. 2014

Journal of Aircraft

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“…For a detailed description refer to Akkermans et al 2 The propeller is explained by Lenfers in. 14 The experiments took place in NWB's open test section. The numerical set-up is slightly simplified.…”

Section: Validationmentioning

confidence: 99%

Installation Effects of a Propeller Mounted on a Wing with Coanda Flap. Part II: Numerical Investigation and Experimental Validation

Dierke

Akkermans

Delfs

et al. 2014

20th AIAA/CEAS Aeroacoustics Conference

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Within the framework of the German project "Bürgernahes Flugzeug" (Citizen Friendly Aircraft), we are investigating the effect of installation on propeller sound. A nine-bladed propeller installed in front of a wing equipped with a Coanda flap is considered. This configuration produces significant high lift and thereby considerably influences the inflow condition of the propeller. The sound generated by the propeller is furthermore shielded by and reflected off the wing. In this contribution, we present an implementation of an acoustic propeller model in a finite differences CAA (computational aeroacoustics) code. Comparisons of isolated propeller computations in a quiescent flow with an analytical model illustrate the correct numerical implementation. The verification of the implementation is presented for an example of an isolated propeller. A comparison for the installed propeller with experiments is conducted for different settings.

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“…This practice ensures that locally varying flow conditions in front of the wing and the nacelle are accounted for. The underlying blade data were provided by another SFB 880 work package [15] and evolved from a propeller design carried out in a related project [16], Three different thrust settings are investigated. Besides the zero-thrust case (TnT), the case of drag compensation (7 j) at = 0.033 and a = 0 deg and the case of maximum thrust (T2) are discussed (Tables 2 and 3).…”

Section: Test Configurationmentioning

confidence: 99%

Numerical Investigation of Engine Effects on a Transport Aircraft with Circulation Control

Keller

Rudnik

2015

Journal of Aircraft

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The scope of this paper is to illustrate the installation effects of a turboprop engine on a high-lift configuration of a short takeoff and landing aircraft with circulation control. In addition to the influence on the wing performance, the impact on the longitudinal static stability of the aircraft is also investigated. Furthermore, critical failure cases, namely one engine inoperative, as well as an asymmetric circulation control failure, are assessed. Therefore, steady computational-fluid-dynamics calculations based on the Reynolds-averaged Navier-Stokes equations were performed. The propeller is modeled with an actuator-disk approach. The results show strong potential of increasing lift by synergy effects between circulation control and propeller slipstream. However, the longitudinal stability and controllability are adversely affected. Regarding the case of one engine inoperative, the resulting yawing moments are twice as high as the actual yawing moments from the asymmetric thrust and are therefore higher than expected. b c CD

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Propeller Design for a future QESTOL Aircraft in the BNF Project

Cited by 12 publications

References 5 publications

Aerodynamic Installation Effects of an Over-the-Wing Propeller on a High-Lift Configuration

Aerodynamic Installation Effects of an Over-the-Wing Propeller on a High-Lift Configuration

Installation Effects of a Propeller Mounted on a Wing with Coanda Flap. Part II: Numerical Investigation and Experimental Validation

Numerical Investigation of Engine Effects on a Transport Aircraft with Circulation Control

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