09 What is DATCOM?
Description
This article is from the Flight Simulators FAQ, by with numerous contributions by Bob Wittick rwittick@msu.edu others.
09 What is DATCOM?
A description of DATCOM, from Dan Sharpes:
The Datcom is the short-hand title for the "USAF Stability and
Control DATCOM." It contains methodologies for determining the S & C
derivatives for just about any type of configuration. It does NOT
contain the S & C derivatives of aircraft (popular misconception!).
Here's what the Guide to Datcom says:
"Fundamentally, the purpose of the Datcom (Data Compendium) {OK, I
was wrong. Flame me!} is to provide a systematic summary of methods
for estimating basic stability and control derivatives. ... For
any given flight condition and configuration the complete set of
derivatives can be determined without resort to outside information.
The book is intended to be used for preliminary design purposes
before the acquisition of test data. ... there are many cases where
the Datcom can be used to advantage in conjunction with test data.
For instance, if the lift-curve slope of a wing-body combination is
desired, the Datcom recommends that the lift-curve slopes of the
isolated wing and body, respectively, be estimated by methods
presented and that appropriate wing-body interference factors (also
presented) be applied. If wing-alone test data are available, it is
obvious that these test data should be substituted in place of the
estimated wing-alone characteristics ..."
The Datcom has nine sections:
1) Guide to Datcom and Methods Summary
2) General Information (notation, parameters of wing, body,
section, and platform)
3) Effects of External Stores
4) Characteristics at Angle of Attack (static derivatives in alpha)
5) Characteristics in Sideslip (static derivatives in beta)
6) Characteristics of High-Lift and Control Devices (section and
wing forces and moments, including hinge moments)
7) Dynamic Derivatives (in p, q, r, alpha-dot, and beta-dot)
8) Mass and Inertia
9) Characteristics of VTOL-STOL Aircraft (thrust characteristics)
The methods are a mixture of theoretical and empirical equations.
Each section starts with a description of the aerodynamics that
contribute to the derivative as appropriate to the configuration.
The methods are then discussed with sample problems following. Next
are the references, the tables showing accuracy of the methods, and
finally, the charts. You'll probably recognize these - several
authors use them liberally in their texts.
Where to get DATCOM:
It's $175. It's distributed in four binders, is 3,200 pages, and can
be ordered from:
Global Engineering
7730 Carondelet Ave. #407
Clayton, Missouri 63105
800-854-7179
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