NASA Scientific and Technical Aerospace Reports
NASA Scientific and Technical Aerospace Reports
NASA Scientific and Technical Aerospace Reports
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An experimental investigation of multidisciplinary (scarfed trailing edge) nozzle divergent flap geometry was conducted<br />
at transonic speeds in the <strong>NASA</strong> Langley 16-Foot Transonic Tunnel. The geometric parameters investigated include nozzle<br />
planform, nozzle contouring location (internal <strong>and</strong>/or external), <strong>and</strong> nozzle area ratio (area ratio 1.2 <strong>and</strong> 2.0). Data were<br />
acquired over a range of Mach Numbers from 0.6 to 1.2, angle-of-attack from 0.0 degrees to 9.6 degrees <strong>and</strong> nozzle pressure<br />
ratios from 1.0 to 20.0. Results showed that increasing the rate of change internal divergence angle across the width of the<br />
nozzle or increasing internal contouring will decrease static, aeropropulsive <strong>and</strong> thrust removed drag performance regardless<br />
of the speed regime. Also, increasing the rate of change in boattail angle across the width of the nozzle or increasing external<br />
contouring will provide the lowest thrust removed drag. Scarfing of the nozzle trailing edges reduces the aeropropulsive<br />
performance for the most part <strong>and</strong> adversely affects the nozzle plume shape at higher nozzle pressure ratios thus increasing<br />
the thrust removed drag. The effects of contouring were primary in nature <strong>and</strong> the effects of planform were secondary in nature.<br />
Larger losses occur supersonically than subsonically when scarfing of nozzle trailing edges occurs. The single sawtooth nozzle<br />
almost always provided lower thrust removed drag than the double sawtooth nozzles regardless the speed regime. If internal<br />
contouring is required, the double sawtooth nozzle planform provides better static <strong>and</strong> aeropropulsive performance than the<br />
single sawtooth nozzle <strong>and</strong> if no internal contouring is required the single sawtooth provides the highest static <strong>and</strong><br />
aeropropulsive performance.<br />
Author<br />
Nozzle Geometry; Planforms; Transonic Speed; Transonic Wind Tunnels; Two Dimensional Models; Parameterization<br />
20040111315 <strong>NASA</strong> Langley Research Center, Hampton, VA, USA<br />
Internal Acoustics Measurements of a Full Scale Advanced Ducted Propulsor Demonstrator<br />
SantaMaria, O. L.; Soderman, P. T.; Horne, W. C.; Jones, M. G.; Bock, L. A.; [1995]; 7 pp.; In English<br />
Report No.(s): AIAA Paper 95-3034; Copyright; Avail: CASI; A02, Hardcopy<br />
Acoustics measurements of a Pratt & Whitney full-scale ADP (Advanced Ducted Propulsor), an ultrahigh by-pass ratio<br />
engine, were conducted in the <strong>NASA</strong> Ames 40- by 80-Foot Wind Tunnel. This paper presents data from measurements taken<br />
from sensors on a fan exit guide vane in the ADP. Data from two sensors, one at mid-span <strong>and</strong> the other at the tip of the fan<br />
exit guide vane, are presented. At the blade passage frequency (BPF), the levels observed at the various engine <strong>and</strong> wind<br />
speeds were higher at the mid-span sensor than the tip sensor. The coherence between these internal sensors <strong>and</strong> external<br />
microphones were calculated <strong>and</strong> plotted as a function of angle (angles ranged from 5 degrees to 160 degrees) relative to the<br />
ADP longitudinal axis. At the highest engine <strong>and</strong> wind speeds, the coherence between the tip sensor <strong>and</strong> the external<br />
microphones was observed to decrease at higher multiples of the BPF. These results suggest that the rotor-stator interaction<br />
tones are stronger in the mid-span region than at the tip.<br />
Author<br />
Acoustic Measurement; Full Scale Tests; Ducted Fan Engines; Wind Tunnel Tests; Aeroacoustics<br />
20040111408 <strong>NASA</strong> Langley Research Center, Hampton, VA, USA<br />
Further Results of Soft-Inplane Tiltrotor Aeromechanics Investigation Using Two Multibody Analyses<br />
Masarati, Pierangelo; Quaranta, Giuseppe; Piatak, David J.; Singleton, Jeffrey D.; [2004]; 16 pp.; In English; AHS<br />
International 60th Annual Forum, 8-10 Jun. 2004, Baltimore, MD, USA<br />
Contract(s)/Grant(s): 23-745-60-RB; Copyright; Avail: CASI; A03, Hardcopy<br />
This investigation focuses on the development of multibody analytical models to predict the dynamic response, aeroelastic<br />
stability, <strong>and</strong> blade loading of a soft-inplane tiltrotor wind-tunnel model. Comprehensive rotorcraft-based multibody analyses<br />
enable modeling of the rotor system to a high level of detail such that complex mechanics <strong>and</strong> nonlinear effects associated<br />
with control system geometry <strong>and</strong> joint deadb<strong>and</strong> may be considered. The influence of these <strong>and</strong> other nonlinear effects on<br />
the aeromechanical behavior of the tiltrotor model are examined. A parametric study of the design parameters which may have<br />
influence on the aeromechanics of the soft-inplane rotor system are also included in this investigation.<br />
Author<br />
Mathematical Models; Tilt Rotor Aircraft; Rotor Blades (Turbomachinery); Loads (Forces); Wind Tunnel Models<br />
20040111448 Air Comm<strong>and</strong> <strong>and</strong> Staff Coll., Maxwell AFB, AL<br />
Uninhabited Air Vehicle Critical Leverage System for Out Nation’s Defense in 2025<br />
O’Reilly, Thomas G.; Apr. 1999; 44 pp.; In English<br />
Report No.(s): AD-A425318; AU/ACSC/152/1999-04; No Copyright; Avail: CASI; A03, Hardcopy<br />
The Air Force 2025 was chartered at the direction of then Chief of Staff of the Air Force (CSAF) Gen Ronald R.<br />
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