ESDU 94044

Excrescence drag levels on aircraft.

Abstract:

ESDU 94044 is based on manufacturer's estimated values for a large number of aircraft as manufactured and provides a guide to standards that have been achieved and a method to obtain a first approximate estimate. In most cases a datum drag parameter is presented at the troposphere and a Mach number of 0.8; a correction factor to other altitudes and speeds whose derivation is included is based on a detailed study of the variation of excrescence drag with Reynolds and Mach numbers. The drag parameter is plotted against wetted area for complete airframes but, for a more detailed estimate, values for some categories of excrescence are also given graphically. They are: surface and control imperfections, air-data systems, lights and beacons, antennas, static discharge wicks, auxiliary power unit, and features required for rain dispersal, for ventilation/cooling, for air-conditioning and for fuel systems. Some information is included on the extent that 'clean-up' has proved possible on several aircraft.

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Details:

Data Item ESDU 94044
Format:	PDF with interactive graphs
Status:	Amendment (A), 01 Nov 2007 Published in Release 2007-04
Previous Releases:	ESDU 94044
ISBN:	978 0 85679 931 0

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This Data Item contains 22 interactive graph(s) as listed below.

Graph	Title
Figure 1	Overall excrescence drag levels on aircraft (at datum conditions of H_p and M)
Figure 2	Excrescence drag levels due to airframe-build surface imperfections (at datum conditions of H_p and M)
Figure 3a	Excrescence drag levels due to imperfections associated with movable aerodynamic surfaces (at datum conditions of H_p and M) - Leading edge devices
Figure 3b	Excrescence drag levels due to imperfections associated with movable aerodynamic surfaces (at datum conditions of H_p and M) - Trailing edge devices
Figure 4b	Excrescence drag levels due to aircraft systems (at datum conditions of H_p and M) - lights and beacons
Figure 4c	Excrescence drag levels due to aircraft systems (at datum conditions of H_p and M) - antennae
Figure 4d	Excrescence drag levels due to aircraft systems (at datum conditions of H_p and M) - static discharge wicks (rigid types)
Figure 4f	Excrescence drag levels due to aircraft systems (at datum conditions of H_p and M) - drains
Figure 4g	Excrescence drag levels due to aircraft systems (at datum conditions of H_p and M) - fuel systems
Figure 5	Excrescence drag levels due to ventilation/cooling systems (at datum conditions of H_p and M)
Figure 6a - Part 1	Excrescence drag levels due to air conditioning systems (at datum conditions of H_p and M)
Figure 6a - Part 2	Excrescence drag levels due to air conditioning systems (at datum conditions of H_p and M)
Figure 6b	Excrescence drag levels due to air conditioning systems (at datum conditions of H_p and M)
Figure 7a	Excrescence drag levels due to auxiliary power unit (at datum conditions of H_p and M)
Figure 7b	Excrescence drag levels due to auxiliary power unit (at datum conditions of H_p and M)
Figure 8a - Part 1	Effects of pressure height and Mach number on excrescence drag
Figure 8a - Part 2	Effects of pressure height and mach number on excrescence drag - aft facing step
Figure 8b - Part 1	Effects of pressure height and mach number on excrescence drag - forward facing step
Figure 8b - Part 2	Effects of pressure height and mach number on excrescence drag - forward facing step
Figure 8c - Part 1	Effects of pressure height and mach number on excrescence drag - groove transverse to flow
Figure 8c - Part 2	Effects of pressure height and mach number on excrescence drag - groove transverse to flow
Figure B1	Values of constants A and B in empirical representation of excrescence drag