Rusty's Reading Room -- q

Rusty --

have you a reading list for Shafer and Iliff and Shafer&Iliff?

/dps

snidely wrote:
Rusty --

have you a reading list for Shafer and Iliff and Shafer&Iliff?

/dps


Subsonic stability and control derivatives for an unpowered, remotely
piloted
3/8-scale F-15 airplane model obtained from flight test

Iliff, K. W.; Maine, R. E.; Shafer, M. F.
NASA Center for AeroSpace Information (CASI)
NASA-TN-D-8136; H-905 , 19760101; Jan 1, 1976
In response to the interest in airplane configuration characteristics
at high angles
of attack, an unpowered remotely piloted 3/8-scale F-15 airplane model
was flight tested. The subsonic stability and control characteristics
of this airplane model over an angle of attack range of -20 to 53 deg
are documented. The remotely piloted technique for obtaining flight
test data was found to provide adequate stability and control
derivatives. The remotely piloted technique provided an opportunity to
test the aircraft mathematical model in an angle of attack regime not
previously examined in flight test. The variation of most of the
derivative estimates with angle of attack was found to be consistent,
particularly when the data were supplemented by uncertainty levels.
Accession ID: 76N15176
Document ID: 19760008088
34-pages

http://ntrs.nasa.gov/archive/nasa/ca...976008088..pdf

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Initial Flight Test of a Ground Deployed System for Flying Qualities
Assessment

Shafer, Mary F.; Koehler, Ruthard; Wilson, Edward M.; Levy, David R.
NASA Dryden Flight Research Center
NASA Technical Memorandum , 1989-08-01
In order to provide a safe, repeatable, precise, high-gain flying
qualities task a ground deployed system was developed and tested at the
NASA Ames Research Center's Dryden Flight Research Facility. This
system, the adaptable target lighting array system (ATLAS), is based on
the German Aerospace Research Establishment's ground attack test
equipment (GRATE). These systems provide a flying-qualities task,
emulating the ground-attack task with ground deployed lighted targets.
These targets light in an unpredictable sequence and the pilot has to
aim the aircraft at whichever target is lighted. Two flight-test
programs were used to assess the suitability of ATLAS. The first
program used the United States Air Force (USAF) NT-33A variability
stability aircraft to establish that ATLAS provided a task suitable for
use in flying qualities research. A head-up display (HUD) tracking task
was used for comparison. The second program used the X-29A
forward-swept wing aircraft to demonstrate that the ATLAS task was
suitable for assessing the flying qualities of a specific experimental
aircraft. In this program, the ground-attack task was used for
comparison. All pilots who used ATLAS found it to be highly
satisfactory and thought it to be superior to the other tasks used in
flying qualities evaluations. They have recommended that it become a
standard for flying qualities evaluations.
10-pages

http://dtrs.dfrc.nasa.gov/archive/00.../01/101700.pdf

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Initial flight test of a ground deployed system for flying qualities
assessment
Shafer, Mary F.; Koehler, Ruthard; Wilson, Edward M.; Levy, David R.
NASA Center for AeroSpace Information (CASI)
NASA-TM-101700; H-1554; NAS 1.15:101700; AIAA PAPER 89-3359; AIAA
Atmospheric Flight Mechanics Conference, Boston, MA, United States,
14-16 Aug. 1989 , 19890801; Aug 1, 1989
In order to provide a safe, repeatable, precise, high-gain flying
qualities task a ground deployed system was developed and tested at the
NASA Ames Research Center's Dryden Flight Research Facility. This
system, the adaptable target lighting array system (ATLAS), is based on
the German Aerospace Research Establishment's ground attack test
equipment (GRATE). These systems provide a flying-qualities task,
emulating the ground-attack task with ground deployed lighted targets.
These targets light in an unpredictable sequence and the pilot has to
aim the aircraft at whichever target is lighted. Two flight-test
programs were used to assess the suitability of ATLAS. The first
program used the United States Air Force (USAF) NT-33A variability
stability aircraft to establish that ATLAS provided a task suitable for
use in flying qualities research. A head-up display (HUD) tracking task
was used for comparison. The second program used the X-29A
forward-swept wing aircraft to demonstrate that the ATLAS task was
suitable for assessing the flying qualities of a specific experimental
aircraft. In this program, the ground-attack task was used for
comparison. All pilots who used ATLAS found it be highly satisfactory
and thought it to be superior to the other tasks used in flying
qualities evaluations. It was recommended that ATLAS become a standard
for flying qualities evaluations.
Accession ID: 91N15182
Document ID: 19910005869
12-pages

http://ntrs.nasa.gov/archive/nasa/ca...991005869..pdf

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In-Flight Simulation Studies at the NASA Dryden Flight Research
Facility
Shafer, Mary F.
NASA Dryden Flight Research Center
NASA Technical Memorandum , 1992-07-01
Since the late 1950's the National Aeronautics and Space
Administration's Dryden Flight Research Facility has found in-flight
simulation to be an invaluable tool. In-flight simulation has been used
to address a wide variety of flying qualities questions, including
low-lift-to-drag ratio approach characteristics for vehicles like the
X-15, the lifting bodies, and the Space Shuttle; the effects of time
delays on controllability of aircraft with digital flight-control
systems, the causes and cures of pilot-induced oscillation in a variety
of aircraft, and flight-control systems for such diverse aircraft as
the X-15 and the X-29. In-flight simulation has also been used to
anticipate problems and to avoid them and to solve problems once they
appear. This paper presents an account of the in-flight simulation at
the Dryden Flight Research Facility and some discussion. An extensive
bibliography is included.
19-pages

http://dtrs.dfrc.nasa.gov/archive/00.../01/TM4396.pdf

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Space Shuttle Hypersonic Aerodynamic and Aerothermodynamic Flight
Research and the Comparison to Ground Test Results
Iliff, Kenneth W.; Shafer, Mary F.
NASA Dryden Flight Research Center
NASA Technical Memorandum , 1993-06-01
Aerodynamic and aerothermodynamic comparisons between flight and ground
test for the Space Shuttle at hypersonic speeds are discussed. All of
the comparisons are taken from papers published by researchers active
in the Space Shuttle program. The aerodynamic comparisons include
stability and control derivatives, center-of-pressure location, and
reaction control jet interaction. Comparisons are also discussed for
various forms of heating, including catalytic, boundary layer, top
centerline, side fuselage, OMS pod, wing leading edge, and shock
interaction. The jet interaction and center-of-pressure location flight
values exceeded not only the predictions but also the uncertainties of
the predictions. Predictions were significantly exceeded for the
heating caused by the vortex impingement on the OMS pods and for
heating caused by the wing leading-edge shock interaction.
29-pages

http://dtrs.dfrc.nasa.gov/archive/00.../01/TM4499.pdf

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Space Shuttle hypersonic aerodynamic and aerothermodynamic flight
research and the comparison to ground test results
Iliff, Kenneth W.; Shafer, Mary F.
NASA Center for AeroSpace Information (CASI)
NASA-TM-4499; H-1894; NAS 1.15:4499; AIAA PAPER 92-3988; Aerospace
Ground Testing Conference, Nashville, TN, United States, 6-8 Jul. 1992
, 19930601; Jun 1, 1993
Aerodynamic and aerothermodynamic comparisons between flight and ground
test for the Space Shuttle at hypersonic speeds are discussed. All of
the comparisons are taken from papers published by researchers active
in the Space Shuttle program. The aerodynamic comparisons include
stability and control derivatives, center-of-pressure location, and
reaction control jet interaction. Comparisons are also discussed for
various forms of heating, including catalytic, boundary layer, top
centerline, side fuselage, OMS pod, wing leading edge, and shock
interaction. The jet interaction and center-of-pressure location flight
values exceeded not only the predictions but also the uncertainties of
the predictions. Predictions were significantly exceeded for the
heating caused by the vortex impingement on the OMS pods and for
heating caused by the wing leading-edge shock interaction.
Accession ID: 94N10820
Document ID: 19940006365
34-pages

http://ntrs.nasa.gov/archive/nasa/ca...994006365..pdf

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Extraction of stability and control derivatives from orbiter flight
data
Iliff, Kenneth W.; Shafer, Mary F.
NASA Center for AeroSpace Information (CASI)
NASA-TM-4500; H-1912; NAS 1.15:4500; Orbiters Experiments (OEX)
Aerothermodynamics Symposium, Williamsburg, VA, United States, 27-30
Apr. 1993 , 19930601; Jun 1, 1993
The Space Shuttle Orbiter has provided unique and important information
on aircraft flight dynamics. This information has provided the
opportunity to assess the flight-derived stability and control
derivatives for maneuvering flight in the hypersonic regime. In the
case of the Space Shuttle Orbiter, these derivatives are required to
determine if certain configuration placards (limitations on the flight
envelope) can be modified. These placards were determined on the basis
of preflight predictions and the associated uncertainties. As
flight-determined derivatives are obtained, the placards are
reassessed, and some of them are removed or modified. Extraction of the
stability and control derivatives was justified by operational
considerations and not by research considerations. Using flight results
to update the predicted database of the orbiter is one of the most
completely documented processes for a flight vehicle. This process
followed from the requirement for analysis of flight data for control
system updates and for expansion of the operational flight envelope.
These results show significant changes in many important stability and
control derivatives from the preflight database. This paper presents
some of the stability and control derivative results obtained from
Space Shuttle flights. Some of the limitations of this information are
also examined.
Accession ID: 94N10707
Document ID: 19940006252
52-pages

http://ntrs.nasa.gov/archive/nasa/ca...994006252..pdf

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A Comparison of Hypersonic Vehicle Flight and Prediction Results
Iliff, Kenneth W.; Shafer, Mary F.
NASA Dryden Flight Research Center
NASA Technical Memorandum , 1995-10-01
Aerodynamic and aerothermodynamic comparisons between flight and ground
test for four hypersonic vehicles are discussed. The four vehicles are
the X-15, the Reentry F, the Sandia Energetic Reentry Vehicle
Experiment (SWERVE), and the Space Shuttle. The comparisons are taken
from papers published by researchers active in the various programs.
Aerodynamic comparisons include reaction control jet interaction on the
Space Shuttle. Various forms of heating including catalytic, boundary
layer, shock interaction and interference, and vortex impingement are
compared. Predictions were significantly exceeded for the heating
caused by vortex impingement (on the Space Shuttle OMS pods) and for
heating caused by shock interaction and interference on the X-15 and
the Space Shuttle. Predictions of boundary-layer state were in error on
the X-15, the SWERVE, and the Space Shuttle vehicles.
44-pages

http://dtrs.dfrc.nasa.gov/archive/00.../01/104313.pdf

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Flight Evaluation of an Aircraft with Side and Center Stick Controllers
and Rate-Limited Ailerons
Deppe, P. R.; Chalk, C. R.; Shafer, M. F.
NASA Center for AeroSpace Information (CASI)
NASA-CR-198055; NAS 1.26:198055 , 19961101; Nov. 1996
As part of an ongoing government and industry effort to study the
flying qualities of aircraft with rate-limited control surface
actuators, two studies were previously flown to examine an algorithm
developed to reduce the tendency for pilot-induced oscillation when
rate limiting occurs. This algorithm, when working properly, greatly
improved the performance of the aircraft in the first study. In the
second study, however, the algorithm did not initially offer as much
improvement. The differences between the two studies caused concern.
The study detailed in this paper was performed to determine whether the
performance of the algorithm was affected by the characteristics of the
cockpit controllers. Time delay and flight control system noise were
also briefly evaluated. An in-flight simulator, the Calspan Learjet 25,
was programmed with a low roll actuator rate limit, and the algorithm
was programmed into the flight control system. Side- and center-stick
controllers, force and position command signals, a rate-limited feel
system, a low-frequency feel system, and a feel system damper were
evaluated. The flight program consisted of four flights and 38
evaluations of test configurations. Performance of the algorithm was
determined to be unaffected by using side- or center-stick controllers
or force or position command signals. The rate-limited feel system
performed as well as the rate-limiting algorithm but was disliked by
the pilots. The low-frequency feel system and the feel system damper
were ineffective. Time delay and noise were determined to degrade the
performance of the algorithm.
Accession ID: 97N12596
Document ID: 19970004404
155-pages

http://ntrs.nasa.gov/archive/nasa/ca...997000627..pdf

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Pilot-Induced Oscillation Research: The Status at the End of the
Century; Volume 1
Shafer, Mary F.; Steinmetz, Paul
NASA Center for AeroSpace Information (CASI)
NASA/CP-2001-210389/VOL1; NAS 1.55:210389/VOL1; H-2407; Pilot-Induced
Oscillation (PIO), Edwards, CA, United States, 6-8 Apr. 1999 ,
20010401; April 2001
The workshop 'Pilot-Induced Oscillation Research: The Status at the End
of the Century,' was held at NASA Dryden Flight Research Center on 6-8
April 1999. The presentations at this conference addressed the most
current information available, addressing regulatory issues, flight
test, safety, modeling, prediction, simulation, mitigation or
prevention, and areas that require further research. All presentations
were approved for publication as unclassified documents with no limits
on their distribution. This proceedings includes the viewgraphs (some
with author's notes) used for thirty presentations that were actually
given and two presentations that were not given because of time
limitations. Four technical papers on this subject are also included.
Document ID: 20010038270
190-pages

http://ntrs.nasa.gov/archive/nasa/ca...001052956..pdf

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Pilot-Induced Oscillation Research: Status at the End of the Century;
Volume 2
Shafer, Mary F.; Steinmetz, Paul
NASA Center for AeroSpace Information (CASI)
NASA/CP-2001-210389/VOL2; H-2407/VOL2; NAS 1.55:210389/VOL2;
Pilot-Induced Oscillation Research: Status at the End of the Century,
Edwards, CA, United States, 6-8 Apr. 1999 , 20010401; April 2001
The workshop 'Pilot-Induced Oscillation Research: The Status at the End
of the Century,' was held at NASA Dryden Flight Research Center on 6-8
April 1999. The presentations at this conference addressed the most
current information available, addressing regulatory issues, flight
test, safety, modeling, prediction, simulation, mitigation or
prevention, and areas that require further research. All presentations
were approved for publication as unclassified documents with no limits
on their distribution. This proceedings includes the viewgraphs (some
with author's notes) used for thirty presentations that were actually
given and two presentations that were not given because of time
limitations. Four technical papers on this subject are also included.
Document ID: 20010038125
150-pages

http://ntrs.nasa.gov/archive/nasa/ca...001052190..pdf

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Pilot-Induced Oscillation Research: Status at the End of the Century;
Volume 3
Shafer, Mary F.; Steinmetz, Paul
NASA Center for AeroSpace Information (CASI)
NASA/CP-2001-210389/VOL3; H-2407/VOL3; H-2419/VOL3; NAS
1.55:210389/VOL3; Pilot-Induced Oscillation Research: Status at the End
of the Century, Edwards, CA, United States, 6-8 Apr. 1999 , 20010401;
April 2001
The workshop 'Pilot-Induced Oscillation Research: The Status at the End
of the Century,' was held at NASA Dryden Flight Research Center on 6-8
April 1999. The presentations at this conference addressed the most
current information available, addressing regulatory issues, flight
test, safety, modeling, prediction, simulation, mitigation or
prevention, and areas that require further research. All presentations
were approved for publication as unclassified documents with no limits
on their distribution. This proceedings includes the viewgraphs (some
with author's notes) used for thirty presentations that were actually
given and two presentations that were not given because of time
limitations. Four technical papers on this subject are also included.
Document ID: 20010037948
194-pages

http://ntrs.nasa.gov/archive/nasa/ca...001053025..pdf

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Recent research directed toward the prediction of lateral-directional
handling qualities
Iliff, K. W.; Taylor, L. W., Jr.
NASA Center for AeroSpace Information (CASI)
NASA-TM-X-59621; AGARD-531 , 19660501; May 1, 1966
Lateral-directional handling qualities survey to develop technique for
predicting pilot ratings
Accession ID: 67N23242
Document ID: 19670013913
24-pages

http://ntrs.nasa.gov/archive/nasa/ca...967013913..pdf

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Fixed-base simulator pilot rating surveys for predicting
lateral-directional handling qualities and pilot rating variability
Iliff, K. W.; Taylor, L. W., Jr.
NASA Center for AeroSpace Information (CASI)
NASA-TN-D-5358 , 19690801; Aug 1, 1969
Pilot ratings of lateral directional handling for wide range of
aircraft characteristics - graphs
Accession ID: 69N35762
Document ID: 19690026384
116-pages

http://ntrs.nasa.gov/archive/nasa/ca...969026384..pdf

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Determination of stability derivatives from flight data using a
Newton-Raphson minimization technique
Iliff, K. W.; Taylor, L. W., Jr.
NASA Center for AeroSpace Information (CASI)
NASA-TN-D-6579; H-626 , 19720301; Mar 1, 1972
A modified Newton-Raphson or quasilinearization minimization technique
for determining stability derivatives from flight data was developed
and compared with simple-equations, analog-matching, least-squares, and
Shinbrot methods of analysis. For the data analyzed, the solutions
computed by using the estimates obtained from the Newton-Raphson
technique fit the data and determined coefficients adequately. A
further modification to include a priori information was found to be
useful. A model statistically similar to the flight data was analyzed
using the same methods (excluding analog matching), and the
Newton-Raphson technique was found to yield superior estimates. An
approximate Cramer-Rao bound was compared with the error covariance
matrix of the model and was found to provide information about the
reliability of the individual estimates obtained. The technique was
successfully applied to data obtained from a light airplane, a large
supersonic airplane, and a lifting body vehicle. It was shown that the
reliability of the estimates of a given coefficient obtained from these
vehicles depends upon the data analyzed.
Accession ID: 72N19659
Document ID: 19720012009
66-pages

http://ntrs.nasa.gov/archive/nasa/ca...972012009..pdf

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Systems identification using a modified Newton-Raphson method: A
FORTRAN program
Taylor, L. W., Jr.; Iliff, K. W.
NASA Center for AeroSpace Information (CASI)
NASA-TN-D-6734; L-8028 , 19720501; May 1, 1972
A FORTRAN program is offered which computes a maximum likelihood
estimate of the parameters of any linear, constant coefficient, state
space model. For the case considered, the maximum likelihood estimate
can be identical to that which minimizes simultaneously the weighted
mean square difference between the computed and measured response of a
system and the weighted square of the difference between the estimated
and a priori parameter values. A modified Newton-Raphson or
quasilinearization method is used to perform the minimization which
typically requires several iterations. A starting technique is used
which insures convergence for any initial values of the unknown
parameters. The program and its operation are described in sufficient
detail to enable the user to apply the program to his particular
problem with a minimum of difficulty.
Accession ID: 72N22581
Document ID: 19720014931
78-pages

http://ntrs.nasa.gov/archive/nasa/ca...972014931..pdf

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A FORTRAN program for determining aircraft stability and control
derivatives from flight data
Maine, R. E.; Iliff, K. W.
NASA Center for AeroSpace Information (CASI)
NASA-TN-D-7831; H-856 , 19750401; Apr 1, 1975
A digital computer program written in FORTRAN IV for the estimation of
aircraft stability and control derivatives is presented. The program
uses a maximum likelihood estimation method, and two associated
programs for routine, related data handling are also included. The
three programs form a package that can be used by relatively
inexperienced personnel to process large amounts of data with a minimum
of manpower. This package was used to successfully analyze 1500
maneuvers on 20 aircraft, and is designed to be used without
modification on as many types of computers as feasible. Program
listings and sample check cases are included.
Accession ID: 75N25621
Document ID: 19750017549
181-pages

http://ntrs.nasa.gov/archive/nasa/ca...975017549..pdf

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Practical aspects of a maximum likelihood estimation method to extract
stability and control derivatives from flight data
Iliff, K. W.; Maine, R. E.
NASA Center for AeroSpace Information (CASI)
NASA-TN-D-8209; H-908 , 19760401; Apr 1, 1976
A maximum likelihood estimation method was applied to flight data and
procedures to facilitate the routine analysis of a large amount of
flight data were described. Techniques that can be used to obtain
stability and control derivatives from aircraft maneuvers that are less
than ideal for this purpose are described. The techniques involve
detecting and correcting the effects of dependent or nearly dependent
variables, structural vibration, data drift, inadequate
instrumentation, and difficulties with the data acquisition system and
the mathematical model. The use of uncertainty levels and multiple
maneuver analysis also proved to be useful in improving the quality of
the estimated coefficients. The procedures used for editing the data
and for overall analysis are also discussed.
Accession ID: 76N23272
Document ID: 19760016184
35-pages

http://ntrs.nasa.gov/archive/nasa/ca...976016184..pdf

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Important factors in the maximum likelihood analysis of flight test
maneuvers
Iliff, K. W.; Maine, R. E.; Montgomery, T. D.
NASA Center for AeroSpace Information (CASI)
NASA-TP-1459; H-1076 , 19790401; Apr 1, 1979
The information presented is based on the experience in the past 12
years at the NASA Dryden Flight Research Center of estimating stability
and control derivatives from over 3500 maneuvers from 32 aircraft. The
overall approach to the analysis of dynamic flight test data is
outlined. General requirements for data and instrumentation are
discussed and several examples of the types of problems that may be
encountered are presented.
Accession ID: 79N22113
Document ID: 19790013942
45-pages

http://ntrs.nasa.gov/archive/nasa/ca...979013942..pdf

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User's manual for MMLE3, a general FORTRAN program for maximum
likelihood parameter estimation
Maine, R. E.; Iliff, K. W.
NASA Center for AeroSpace Information (CASI)
NASA-TP-1563; H-1084 , 19801101; Nov 1, 1980
A user's manual for the FORTRAN IV computer program MMLE3 is described.
It is a maximum likelihood parameter estimation program capable of
handling general bilinear dynamic equations of arbitrary order with
measurement noise and/or state noise (process noise). The theory and
use of the program is described. The basic MMLE3 program is quite
general and, therefore, applicable to a wide variety of problems. The
basic program can interact with a set of user written problem specific
routines to simplify the use of the program on specific systems. A set
of user routines for the aircraft stability and control derivative
estimation problem is provided with the program.
Accession ID: 81N12744
Document ID: 19810004233
96-pages

http://ntrs.nasa.gov/archive/nasa/ca...981004233..pdf

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The theory and practice of estimating the accuracy of dynamic
flight-determined coefficients
Maine, R. E.; Iliff, K. W.
NASA Center for AeroSpace Information (CASI)
NASA-RP-1077; H-1128 , 19810701; Jul 1, 1981
Means of assessing the accuracy of maximum likelihood parameter
estimates obtained from dynamic flight data are discussed. The most
commonly used analytical predictors of accuracy are derived and
compared from both statistical and simplified geometrics standpoints.
The accuracy predictions are evaluated with real and simulated data,
with an emphasis on practical considerations, such as modeling error.
Improved computations of the Cramer-Rao bound to correct large
discrepancies due to colored noise and modeling error are presented.
The corrected Cramer-Rao bound is shown to be the best available
analytical predictor of accuracy, and several practical examples of the
use of the Cramer-Rao bound are given. Engineering judgement, aided by
such analytical tools, is the final arbiter of accuracy estimation.
Accession ID: 81N27865
Document ID: 19810019327
65-pages

http://ntrs.nasa.gov/archive/nasa/ca...981019327..pdf

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Application of parameter estimation to aircraft stability and control:
The output-error approach
Maine, Richard E.; Iliff, Kenneth W.
NASA Center for AeroSpace Information (CASI)
NASA-RP-1168; H-1299; NAS 1.61:1168 , 19860601; Jun 1, 1986
The practical application of parameter estimation methodology to the
problem of estimating aircraft stability and control derivatives from
flight test data is examined. The primary purpose of the document is to
present a comprehensive and unified picture of the entire parameter
estimation process and its integration into a flight test program. The
document concentrates on the output-error method to provide a focus for
detailed examination and to allow us to give specific examples of
situations that have arisen. The document first derives the aircraft
equations of motion in a form suitable for application to estimation of
stability and control derivatives. It then discusses the issues that
arise in adapting the equations to the limitations of analysis
programs, using a specific program for an example. The roles and issues
relating to mass distribution data, preflight predictions, maneuver
design, flight scheduling, instrumentation sensors, data acquisition
systems, and data processing are then addressed. Finally, the document
discusses evaluation and the use of the analysis results.
Accession ID: 87N29499
Document ID: 19870020066
177-pages

http://ntrs.nasa.gov/archive/nasa/ca...987020066..pdf

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Bibliography for aircraft parameter estimation
Iliff, Kenneth W.; Maine, Richard E.
NASA Center for AeroSpace Information (CASI)
NASA-TM-86804; H-1358; NAS 1.15:86804 , 19861001; Oct 1, 1986
An extensive bibliography in the field of aircraft parameter estimation
has been compiled. This list contains definitive works related to most
aircraft parameter estimation approaches. Theoretical studies as well
as practical applications are included. Many of these publications are
pertinent to subjects peripherally related to parameter estimation,
such as aircraft maneuver design or instrumentation considerations.
Accession ID: 87N29498
Document ID: 19870020065
22-pages

http://ntrs.nasa.gov/archive/nasa/ca...987020065..pdf

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Aircraft Parameter Estimation- AIAA Dryden Lecture in Research for 1987
Iliff, Kenneth W.
NASA Dryden Flight Research Center
NASA Technical Memorandum , 1987-01-01
The aircraft parameter estimation problem is used to illustrate the
utility of parameter estimation, which applies to many engineering and
scientific fields. Maximum likelihood estimation has been used to
extract stability and control derivatives from flight data for many
years. This paper presents some of the basic concepts of aircraft
parameter estimation and briefly surveys the literature in the field.
The maximum likelihood estimator is discussed, and the basic concepts
of minimization and estimation are examined for a simple simulated
aircraft example. The cost functions that are to be minimized during
estimation are defined and discused. Graphic representations of the
cost functions are given to illustrate the minimization process.
Finally, the basic concepts are generalized, and estimation from flight
data is discussed. Some of the major conclusions for the simulated
example are also developed for the analysis of flight data from the
F-14, highly maneuverable aircraft technology (HiMAT), and space
shuttle vehicles.
29-pages

http://dtrs.dfrc.nasa.gov/archive/00000508/01/88281.pdf

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Aircraft parameter estimation
Iliff, Kenneth W.
NASA Center for AeroSpace Information (CASI)
NASA-TM-88281; H-1394; NAS 1.15:88281 , 19870101; Jan 1, 1987
The aircraft parameter estimation problem is used to illustrate the
utility of parameter estimation, which applies to many engineering and
scientific fields. Maximum likelihood estimation has been used to
extract stability and control derivatives from flight data for many
years. This paper presents some of the basic concepts of aircraft
parameter estimation and briefly surveys the literature in the field.
The maximum likelihood estimator is discussed, and the basic concepts
of minimization and estimation are examined for a simple simulated
aircraft example. The cost functions that are to be minimized during
estimation are defined and discussed. Graphic representations of the
cost functions are given to illustrate the minimization process.
Finally, the basic concepts are generalized, and estimation from flight
data is discussed. Some of the major conclusions for the simulated
example are also developed for the analysis of flight data from the
F-14, highly maneuverable aircraft technology (HiMAT), and space
shuttle vehicles.
Accession ID: 87N19376
Document ID: 19870009943
31-pages

http://ntrs.nasa.gov/archive/nasa/ca...987009943..pdf

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X-29A Lateral-Directional Stability and Control Derivatives Extracted
From High-Angle-of-Attack Flight Data
Iliff, Kenneth W.; Wang, Kon-Sheng Charles
NASA Dryden Flight Research Center
NASA Technical Publication , 1996-12-01
The lateral-directional stability and control derivatives of the
X-29A number 2 are extracted from flight data over an angle-of-attack
range of 4° to 53° using a parameter identification algorithm. The
algorithm uses the linearized aircraft equations of motion and a
maximum likelihood estimator in the presence of state and measurement
noise. State noise is used to model the uncommanded forcing function
caused by unsteady aerodynamics over the aircraft at angles of attack
above 15°. The results supported the flight-envelope-expansion phase
of the X-29A number 2 by helping to update the aerodynamic mathematical
model, to improve the real-time simulator, and to revise flight control
system laws. Effects of the aircraft high gain flight control system on
maneuver quality and the estimated derivatives are also discussed. The
derivatives are plotted as functions of angle of attack and compared
with the predicted aerodynamic database. Agreement between predicted
and flight values is quite good for some derivatives such as the
lateral force due to sideslip, the lateral force due to rudder
deflection, and the rolling moment due to roll rate. The results also
show significant differences in several important derivatives such as
the rolling moment due to sideslip, the yawing moment due to sideslip,
the yawing moment due to aileron deflection, and the yawing moment due
to rudder deflection.
39-pages

http://dtrs.dfrc.nasa.gov/archive/00.../01/TP3664.pdf

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X-29A Lateral-Directional Stability and Control Derivatives Extracted
From High-Angle-of-Attack Flight Data
Iliff, Kenneth W.; Wang, Kon-Sheng Charles Wang
NASA Center for AeroSpace Information (CASI)
NASA-TP-3664; NAS 1.60:3664; H-2118 , 19961201; Dec. 1996
The lateral-directional stability and control derivatives of the X-29A
number 2 are extracted from flight data over an angle-of-attack range
of 4 degrees to 53 degrees using a parameter identification algorithm.
The algorithm uses the linearized aircraft equations of motion and a
maximum likelihood estimator in the presence of state and measurement
noise. State noise is used to model the uncommanded forcing function
caused by unsteady aerodynamics over the aircraft at angles of attack
above 15 degrees. The results supported the flight-envelope-expansion
phase of the X-29A number 2 by helping to update the aerodynamic
mathematical model, to improve the real-time simulator, and to revise
flight control system laws. Effects of the aircraft high gain flight
control system on maneuver quality and the estimated derivatives are
also discussed. The derivatives are plotted as functions of angle of
attack and compared with the predicted aerodynamic database. Agreement
between predicted and flight values is quite good for some derivatives
such as the lateral force due to sideslip, the lateral force due to
rudder deflection, and the rolling moment due to roll rate. The results
also show significant differences in several important derivatives such
as the rolling moment due to sideslip, the yawing moment due to
sideslip, the yawing moment due to aileron deflection, and the yawing
moment due to rudder deflection.
Accession ID: 97N12640
Document ID: 19970004545
41-pages

http://ntrs.nasa.gov/archive/nasa/ca...997000539..pdf

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Extraction of Lateral-Directional Stability and Control Derivatives for
the Basic F-18 Aircraft at High Angles of Attack
Iliff, Kenneth W.; Wang, Kon-Sheng Charles
NASA Dryden Flight Research Center
NASA Technical Memorandum , 1997-02-01
The results of parameter identification to determine the
lateral-directional stability and control derivatives of an F-18
research aircraft in its basic hardware and software configuration are
presented. The derivatives are estimated from dynamic flight data using
a specialized identification program developed at NASA Dryden Flight
Research Center. The formulation uses the linearized aircraft equations
of motions in their continuous/discrete form and a maximum likelihood
estimator that accounts for both state and measurement noise. State
noise is used to model the uncommanded forcing function caused by
unsteady aerodynamics, such as separated and vortical flows, over the
aircraft. The derivatives are plotted as functions of angle of attack
between 3 degrees and 47 degrees and compared with wind-tunnel
predictions. The quality of the derivative estimates obtained by
parameter identification is somewhat degraded because the maneuvers
were flown with the aircraft's control augmentation system engaged,
which introduced relatively high correlations between the control
variables and response variables as a result of control motions from
the feedback control system.
39-pages

http://dtrs.dfrc.nasa.gov/archive/00000110/01/4786.pdf

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Flight-Determined Subsonic Longitudinal Stability and Control
Derivatives of the F-18 High Angle of Attack Research Vehicle (HARV)
With Thrust Vectoring
Iliff, Kenneth W.; Wang, Kon-Sheng Charles
NASA Dryden Flight Research Center
NASA Technical Publication , 1997-12-01
The subsonic longitudinal stability and control derivatives of the F-18
High Angle of Attack Research Vehicle (HARV) are extracted from dynamic
flight data using a maximum likelihood parameter identification
technique. The technique uses the linearized aircraft equations of
motion in their continuous/discrete form and accounts for state and
measurement noise as well as thrust-vectoring effects. State noise is
used to model the uncommanded forcing function caused by unsteady
aerodynamics over the aircraft, particularly at high angles of attack.
Thrust vectoring was implemented using electrohydraulically-actuated
nozzle postexit vanes and a specialized research flight control system.
During maneuvers, a control system feature provided independent
aerodynamic control surface inputs and independent thrust-vectoring
vane inputs, thereby eliminating correlations between the aircraft
states and controls. Substantial variations in control excitation and
dynamic response were exhibited for maneuvers conducted at different
angles of attack. Opposing vane interactions caused most
thrust-vectoring inputs to experience some exhaust plume interference
and thus reduced effectiveness. The estimated stability and control
derivatives are plotted, and a discussion relates them to predicted
values and maneuver quality.
72-pages

http://dtrs.dfrc.nasa.gov/archive/00.../01/206539.pdf

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Flight-Determined Subsonic Longitudinal Stability and Control
Derivatives of the F-18 High Angle of Attack Research Vehicle (HARV)
with Thrust Vectoring
Iliff, Kenneth W.; Wang, Kon-Sheng Charles
NASA Center for AeroSpace Information (CASI)
NASA/TP-97-206539; NAS 1.60:206539; H-2175 , 19970101; Dec. 1997
The subsonic longitudinal stability and control derivatives of the F-18
High Angle of Attack Research Vehicle (HARV) are extracted from dynamic
flight data using a maximum likelihood parameter identification
technique. The technique uses the linearized aircraft equations of
motion in their continuous/discrete form and accounts for state and
measurement noise as well as thrust-vectoring effects. State noise is
used to model the uncommanded forcing function caused by unsteady
aerodynamics over the aircraft, particularly at high angles of attack.
Thrust vectoring was implemented using electrohydraulically-actuated
nozzle postexit vanes and a specialized research flight control system.
During maneuvers, a control system feature provided independent
aerodynamic control surface inputs and independent thrust-vectoring
vane inputs, thereby eliminating correlations between the aircraft
states and controls. Substantial variations in control excitation and
dynamic response were exhibited for maneuvers conducted at different
angles of attack. Opposing vane interactions caused most
thrust-vectoring inputs to experience some exhaust plume interference
and thus reduced effectiveness. The estimated stability and control
derivatives are plotted, and a discussion relates them to predicted
values and maneuver quality.
Document ID: 19980007172
72-pages

http://ntrs.nasa.gov/archive/nasa/ca...998042172..pdf

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Extraction of Lateral-Directional Stability and Control Derivatives for
the Basic F-18 Aircraft at High Angles of Attack
Iliff, Kenneth W.; Wang, Kon-Sheng Charles
NASA Center for AeroSpace Information (CASI)
NASA-TM-4786; H-2143; NAS 1.15:4786 , 19970201; Feb. 1997
The results of parameter identification to determine the
lateral-directional stability and control derivatives of an F-18
research aircraft in its basic hardware and software configuration are
presented. The derivatives are estimated from dynamic flight data using
a specialized identification program developed at NASA Dryden Flight
Research Center. The formulation uses the linearized aircraft equations
of motions in their continuous/discrete form and a maximum likelihood
estimator that accounts for both state and measurement noise. State
noise is used to model the uncommanded forcing function caused by
unsteady aerodynamics, such as separated and vortical flows, over the
aircraft. The derivatives are plotted as functions of angle of attack
between 3 deg and 47 deg and compared with wind-tunnel predictions. The
quality of the derivative estimates obtained by parameter
identification is somewhat degraded because the maneuvers were flown
with the aircraft's control augmentation system engaged, which
introduced relatively high correlations between the control variables
and response variables as a result of control motions from the feedback
control system.
Accession ID: 97N15708
Document ID: 19970010502
42-pages

http://ntrs.nasa.gov/archive/nasa/ca...997015287..pdf

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Flight Stability and Control and Performance Results from the Linear
Aerospike SR-71 Experiment (LASRE)
Moes, Timothy R.; Cobleigh, Brent R.; Cox, Timothy H.; Conners, Timothy
R.; Iliff, Kenneth W.; Powers, Bruce G.
NASA Dryden Flight Research Center
NASA Technical Memorandum , 1998-08-01
The Linear Aerospike SR-71 Experiment (LASRE) is presently being
conducted to test a 20-percent-scale version of the Linear Aerospike
rocket engine. This rocket engine has been chosen to power the X-33
Single Stage to Orbit Technology Demonstrator Vehicle. The rocket
engine was integrated into a lifting body configuration and mounted to
the upper surface of an SR-71 aircraft. This paper presents stability
and control results and performance results from the envelope expansion
flight tests of the LASRE configuration up to Mach 1.8 and compares the
results with wind tunnel predictions. Longitudinal stability and
elevator control effectiveness were well-predicted from wind tunnel
tests. Zero-lift pitching moment was mispredicted transonically.
Directional stability, dihedral stability, and rudder effectiveness
were overpredicted. The SR-71 handling qualities were never
significantly impacted as a result of the missed predictions.
Performance results confirmed the large amount of wind-tunnel-predicted
transonic drag for the LASRE configuration. This drag increase made the
performance of the vehicle so poor that acceleration through transonic
Mach numbers could not be achieved on a hot day without depleting the
available fuel.
32-pages

http://dtrs.dfrc.nasa.gov/archive/00.../01/206565.pdf

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Flight Stability and Control and Performance Results from the Linear
Aerospike SR-71 Experiment (LASRE)
Moes, Timothy R.; Cobleigh, Brent R.; Cox, Timothy H.; Conners, Timothy
R.; Iliff, Kenneth W.; Powers, Bruce G.
NASA Center for AeroSpace Information (CASI)
NASA/TM-1998-206565; H-2276; NAS 1.15:206565; Atmosphere Flight
Mechanics, Boston, MA, United States, 10-12 Aug. 1998 , 19980801; Aug.
1998
The Linear Aerospike SR-71 Experiment (LASRE) is presently being
conducted to test a 20-percent-scale version of the Linear Aerospike
rocket engine. This rocket engine has been chosen to power the X-33
Single Stage to Orbit Technology Demonstrator Vehicle. The rocket
engine was integrated into a lifting body configuration and mounted to
the upper surface of an SR-71 aircraft. This paper presents stability
and control results and performance results from the envelope expansion
flight tests of the LASRE configuration up to Mach 1.8 and compares the
results with wind tunnel predictions. Longitudinal stability and
elevator control effectiveness were well-predicted from wind tunnel
tests. Zero-lift pitching moment was mispredicted transonically.
Directional stability, dihedral stability, and rudder effectiveness
were overpredicted. The SR-71 handling qualities were never
significantly impacted as a result of the missed predictions.
Performance results confirmed the large amount of wind-tunnel-predicted
transonic drag for the LASRE configuration. This drag increase made the
performance of the vehicle so poor that acceleration through transonic
Mach numbers could not be achieved on a hot day without depleting the
available fuel.
Document ID: 19980217098
30-pages

http://ntrs.nasa.gov/archive/nasa/ca...998361052..pdf

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Flight-Determined, Subsonic, Lateral-Directional Stability and Control
Derivatives of the Thrust-Vectoring F-18 High Angle of Attack Research
Vehicle (HARV), and Comparisons to the Basic F-18 and Predicted
Derivatives
Iliff, Kenneth W.; Wang, Kon-Sheng Charles
NASA Dryden Flight Research Center
NASA Technical Publication , 1999-01-01
The subsonic, lateral-directional, stability and control derivatives of
the thrust-vectoring F-18 High Angle of Attack Research Vehicle (HARV)
are extracted from flight data using a maximum likelihood parameter
identification technique. State noise is accounted for in the
identification formulation and is used to model the uncommanded forcing
functions caused by unsteady aerodynamics. Preprogrammed maneuvers
provided independent control surface inputs, eliminating problems of
identifiability related to correlations between the aircraft controls
and states. The HARV derivatives are plotted as functions of angles of
attack between 10° and 70° and compared to flight estimates from the
basic F-18 aircraft and to predictions from ground and wind-tunnel
tests. Unlike maneuvers of the basic F-18 aircraft, the HARV maneuvers
were very precise and repeatable, resulting in tightly clustered
estimates with small uncertainty levels. Significant differences were
found between flight and prediction; however, some of these differences
may be attributed to differences in the range of sideslip or input
amplitude over which a given derivative was evaluated, and to
differences between the HARV external configuration and that of the
basic F-18 aircraft, upon which most of the prediction was based. Some
HARV derivative fairings have been adjusted using basic F-18
derivatives (with low uncertainties) to help account for differences in
variable ranges and the lack of HARV maneuvers at certain angles of
attack.
90-pages

http://dtrs.dfrc.nasa.gov/archive/00.../01/206573.pdf

------------------------------------------------------------------------------------

Flight-Determined, Subsonic, Lateral-Directional Stability and Control
Derivatives of the Thrust-Vectoring F-18 High Angle of Attack Research
Vehicle (HARV), and Comparisons to the Basic F-18 and Predicted
Derivatives
Iliff, Kenneth W.; Wang, Kon-Sheng Charles
NASA Center for AeroSpace Information (CASI)
NASA/TP-1999-206573; NAS 1.60:206573; H-2252 , 19990101; January 1999
The subsonic, lateral-directional, stability and control derivatives of
the thrust-vectoring F-1 8 High Angle of Attack Research Vehicle (HARV)
are extracted from flight data using a maximum likelihood parameter
identification technique. State noise is accounted for in the
identification formulation and is used to model the uncommanded forcing
functions caused by unsteady aerodynamics. Preprogrammed maneuvers
provided independent control surface inputs, eliminating problems of
identifiability related to correlations between the aircraft controls
and states. The HARV derivatives are plotted as functions of angles of
attack between 10deg and 70deg and compared to flight estimates from
the basic F-18 aircraft and to predictions from ground and wind tunnel
tests. Unlike maneuvers of the basic F-18 aircraft, the HARV maneuvers
were very precise and repeatable, resulting in tightly clustered
estimates with small uncertainty levels. Significant differences were
found between flight and prediction; however, some of these differences
may be attributed to differences in the range of sideslip or input
amplitude over which a given derivative was evaluated, and to
differences between the HARV external configuration and that of the
basic F-18 aircraft, upon which most of the prediction was based. Some
HARV derivative fairings have been adjusted using basic F-18
derivatives (with low uncertainties) to help account for differences in
variable ranges and the lack of HARV maneuvers at certain angles of
attack.
Document ID: 19990019364
90-pages

http://ntrs.nasa.gov/archive/nasa/ca...999018525..pdf

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Aerodynamic Lift and Moment Calculations Using a Closed-Form Solution
of the Possio Equation
Lin, Jensen; Iliff, Kenneth W.
NASA Dryden Flight Research Center
NASA Technical Memorandum , 2000-04-01
In this paper, we present closed-form formulas for the lift and moment
coefficients of a lifting surface in two-dimensional, unsteady,
compressible, subsonic flow utilizing a newly developed explicit
analytical solution of the Possio equation. Numerical calculations are
consistent with previous numerical tables based on series expansions or
ad hoc numerical schemes. More importantly, these formulas lend
themselves readily to flutter analysis, compared with the tedious
table-look-up schemes currently in use.
27-pages

http://dtrs.dfrc.nasa.gov/archive/00.../01/209019.pdf

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Results From F-18B Stability and Control Parameter Estimation Flight
Tests at High Dynamic Pressures
Moes, Timothy R.; Noffz, Gregory K.; Iliff, Kenneth W.
NASA Dryden Flight Research Center
NASA Technical Publication , 2000-11-01
A maximum-likelihood output-error parameter estimation technique has
been used to obtain stability and control derivatives for the NASA
F-18B Systems Research Aircraft. This work has been performed to
support flight testing of the active aeroelastic wing (AAW) F-18A
project. The goal of this research is to obtain baseline F-18 stability
and control derivatives that will form the foundation of the
aerodynamic model for the AAW aircraft configuration. Flight data have
been obtained at Mach numbers between 0.85 and 1.30 and at dynamic
pressures ranging between 600 and 1500 pound-force per square foot. At
each test condition, longitudinal and lateral-directional doublets have
been performed using an automated onboard excitation system. The
doublet maneuver consists of a series of single-surface inputs so that
individual control-surface motions cannot be correlated with other
control-surface motions. Flight test results have shown that several
stability and control derivatives are significantly different than
prescribed by the F-18B aerodynamic model. This report defines the
parameter estimation technique used, presents stability and control
derivative results, compares the results with predictions based on the
current F-18B aerodynamic model, and shows improvements to the
nonlinear simulation using updated derivatives from this research.
143-pages

http://dtrs.dfrc.nasa.gov/archive/00.../01/209033.pdf

------------------------------------------------------------------------------------

Aerodynamic Lift and Moment Calculations Using a Closed-Form Solution
of the Possio Equation
Lin, Jensen; Iliff, Kenneth W.
NASA Center for AeroSpace Information (CASI)
NASA/TM-2000-209019; NAS 1.15:209019; H-2374 , 20000401; April 2000
In this paper, we present closed-form formulas for the lift and moment
coefficients of a lifting surface in two dimensional, unsteady,
compressible, subsonic flow utilizing a newly developed explicit
analytical solution of the Possio equation. Numerical calculations are
consistent with previous numerical tables based on series expansions or
ad hoc numerical schemes. More importantly, these formulas lend
themselves readily to flutter analysis, compared with the tedious
table-look-up schemes currently in use.
Document ID: 20000037779
26-pages

http://ntrs.nasa.gov/archive/nasa/ca...000047713..pdf

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Results From F-18B Stability and Control Parameter Estimation Flight
Tests at High Dynamic Pressures
Moes, Timothy R.; Noffz, Gregory K.; Iliff, Kenneth W.
NASA Center for AeroSpace Information (CASI)
NASA/TP-2000-209033; H-2424; NAS 1.60:209033 , 20001101; November 2000
A maximum-likelihood output-error parameter estimation technique has
been used to obtain stability and control derivatives for the NASA
F-18B Systems Research Aircraft. This work has been performed to
support flight testing of the active aeroelastic wing (AAW) F-18A
project. The goal of this research is to obtain baseline F-18 stability
and control derivatives that will form the foundation of the
aerodynamic model for the AAW aircraft configuration. Flight data have
been obtained at Mach numbers between 0.85 and 1.30 and at dynamic
pressures ranging between 600 and 1500 lbf/sq ft. At each test
condition, longitudinal and lateral-directional doublets have been
performed using an automated onboard excitation system. The doublet
maneuver consists of a series of single-surface inputs so that
individual control-surface motions cannot be correlated with other
control-surface motions. Flight test results have shown that several
stability and control derivatives are significantly different than
prescribed by the F-18B aerodynamic model. This report defines the
parameter estimation technique used, presents stability and control
derivative results, compares the results with predictions based on the
current F-18B aerodynamic model, and shows improvements to the
nonlinear simulation using updated derivatives from this research.
Document ID: 20010002099
143-pages

http://ntrs.nasa.gov/archive/nasa/ca...000181649..pdf

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Stability and Control Estimation Flight Test Results for the SR-71
Aircraft With Externally Mounted Experiments
Moes, Timothy R.; Iliff, Kenneth
NASA Dryden Flight Research Center
NASA Technical Publication , 2002-06-01
A maximum-likelihood output-error parameter estimation technique is
used to obtain stability and control derivatives for the NASA Dryden
Flight Research Center SR-71A airplane and for configurations that
include experiments externally mounted to the top of the fuselage. This
research is being done as part of the envelope clearance for the new
experiment configurations. Flight data are obtained at speeds ranging
from Mach 0.4 to Mach 3.0, with an extensive amount of test points at
approximately Mach 1.0. Pilot-input pitch and yaw-roll doublets are
used to obtain the data. This report defines the parameter estimation
technique used, presents stability and control derivative results, and
compares the derivatives for the three configurations tested. The
experimental configurations studied generally show acceptable
stability, control, trim, and handling qualities throughout the Mach
regimes tested. The reduction of directional stability for the
experimental configurations is the most significant aerodynamic effect
measured and identified as a design constraint for future experimental
configurations. This report also shows the significant effects of
aircraft flexibility on the stability and control derivatives.
96-pages

http://dtrs.dfrc.nasa.gov/archive/00.../01/210718.pdf

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Aerodynamic Assessment of Flight-Determined Subsonic Lift and Drag
Characteristics of Seven Lifting-Body and Wing-Body Reentry Vehicle
Configurations
Saltzman, Edwin J.; Wang, K. Charles; Iliff, Kenneth W.
NASA Dryden Flight Research Center
NASA Technical Publication , 2002-11-01
This report examines subsonic flight-measured lift and drag
characteristics of seven lifting-body and wing-body reentry vehicle
configurations with truncated bases. The seven vehicles are the
full-scale M2-F1, M2-F2, HL-10, X-24A, X-24B, and X-15 vehicles and the
Space Shuttle Enterprise. Subsonic flight lift and drag data of the
various vehicles are assembled under aerodynamic performance parameters
and presented in several analytical and graphical formats. These
formats are intended to unify the data and allow a greater
understanding than individually studying the vehicles allows.
Lift-curve slope data are studied with respect to aspect ratio and
related to generic wind-tunnel model data and to theory for
low-aspect-ratio planforms. The definition of reference area is
critical for understanding and comparing the lift data. The drag
components studied include minimum drag coefficient, lift-related drag,
maximum lift-to-drag ratio, and, where available, base pressure
coefficients. The influence of forebody drag on afterbody and base drag
at low lift is shown to be related to Hoerner's compilation for body,
airfoil, nacelle, and canopy drag. This feature may result in a reduced
need of surface smoothness for vehicles with a large ratio of base area
to wetted area. These analyses are intended to provide a useful
analytical framework with which to compare and evaluate new vehicle
configurations of the same generic family.
159-pages

http://dtrs.dfrc.nasa.gov/archive/00.../01/209032.pdf

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Stability and Control Estimation Flight Test Results for the SR-71
Aircraft With Externally Mounted Experiments
Moes, Timothy R.; Iliff, Kenneth
NASA Center for AeroSpace Information (CASI)
NASA/TP-2002-210718; H-2465; NAS 1.60:210718 , 20020601; June 2002
A maximum-likelihood output-error parameter estimation technique is
used to obtain stability and control derivatives for the NASA Dryden
Flight Research Center SR-71A airplane and for configurations that
include experiments externally mounted to the top of the fuselage. This
research is being done as part of the envelope clearance for the new
experiment configurations. Flight data are obtained at speeds ranging
from Mach 0.4 to Mach 3.0, with an extensive amount of test points at
approximately Mach 1.0. Pilot-input pitch and yaw-roll doublets are
used to obtain the data. This report defines the parameter estimation
technique used, presents stability and control derivative results, and
compares the derivatives for the three configurations tested. The
experimental configurations studied generally show acceptable
stability, control, trim, and handling qualities throughout the Mach
regimes tested. The reduction of directional stability for the
experimental configurations is the most significant aerodynamic effect
measured and identified as a design constraint for future experimental
configurations. This report also shows the significant effects of
aircraft flexibility on the stability and control derivatives.
Document ID: 20020057965
96-pages

http://ntrs.nasa.gov/archive/nasa/ca...002092400..pdf

------------------------------------------------------------------------------------

Aerodynamic Assessment of Flight-Determined Subsonic Lift and Drag
Characteristics of Seven Lifting-Body and Wing-Body Reentry Vehicle
Configurations
Saltzman, Edwin J.; Wang, K. Charles; Iliff, Kenneth W.
NASA Center for AeroSpace Information (CASI)
NASA/TP-2002-209032; NAS 1.60:209032; H-2397 , 20021101; November 2002
This report examines subsonic flight-measured lift and drag
characteristics of seven lifting-body and wing-body reentry vehicle
configurations with truncated bases. The seven vehicles are the
full-scale M2-F1, M2-F2, HL-10, X-24A, X-24B, and X-15 vehicles and the
Space Shuttle Enterprise. Subsonic flight lift and drag data of the
various vehicles are assembled under aerodynamic performance parameters
and presented in several analytical and graphical formats. These
formats are intended to unify the data and allow a greater
understanding than individually studying the vehicles allows.
Lift-curve slope data are studied with respect to aspect ratio and
related to generic wind-tunnel model data and to theory for
low-aspect-ratio platforms. The definition of reference area is
critical for understanding and comparing the lift data. The drag
components studied include minimum drag coefficient, lift-related drag,
maximum lift-to drag ratio, and, where available, base pressure
coefficients. The influence of forebody drag on afterbody and base drag
at low lift is shown to be related to Hoerner's compilation for body,
airfoil, nacelle, and canopy drag. This feature may result in a reduced
need of surface smoothness for vehicles with a large ratio of base area
to wetted area. These analyses are intended to provide a useful
analytical framework with which to compare and evaluate new vehicle
configurations of the same generic family.
Document ID: 20030003696
160-pages

http://ntrs.nasa.gov/archive/nasa/ca...003000361..pdf

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Asymptotic Distribution of Eigenfrequencies for a Coupled
Eiler-Bernoulli and Timoshenko Beam Model
Iliff, Kenneth W.; Shubov, Marianna A.; Peterson, Cheryl A.
NASA Center for AeroSpace Information (CASI)
NASA/CR-2003-212022; H-2528; NAS 1.26:212022 , 20031101; November 2003
This research is devoted to the asymptotic and spectral analysis of a
coupled Euler-Bernoulli and Timoshenko beam model. The model is
governed by a system of two coupled differential equations and a two
parameter family of boundary conditions modelling the action of
self-straining actuators. The aforementioned equations of motion
together with a two-parameter family of boundary conditions form a
coupled linear hyperbolic system, which is equivalent to a single
operator evolution equation in the energy space. That equation defines
a semigroup of bounded operators. The dynamics generator of the
semigroup is our main object of interest. For each set of boundary
parameters, the dynamics generator has a compact inverse. If both
boundary parameters are not purely imaginary numbers, then the dynamics
generator is a nonselfadjoint operator in the energy space. We
calculate the spectral asymptotics of the dynamics generator. We find
that the spectrum lies in a strip parallel to the horizontal axis, and
is asymptotically close to the horizontal axis - thus the system is
stable, but is not uniformly stable.
Document ID: 20030107609
79-pages

http://ntrs.nasa.gov/archive/nasa/ca...003133555..pdf

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From Runway to Orbit: Reflections of a NASA Engineer
Iliff, Kenneth W.; Peebles, Curtis L.
NASA Center for AeroSpace Information (CASI)
NASA/SP-2004-4109 , 20040101; 2004
In his remarkable memoir Runway to Orbit, Dr. Kenneth W. Iliff - the
recently retired Chief Scientist of the NASA Dryden Flight Research
Center- tells a highly personal, yet a highly persuasive account of the
last forty years of American aeronautical research. His interpretation
of events commands respect, because over these years he has played
pivotal roles in many of the most important American aeronautics and
spaceflight endeavors. Moreover, his narrative covers much of the
second half of the first 100 years of flight, a centennial anniversary
being celebrated this year. aerospace knowledge. He arrived at the then
NASA Flight Research Center in 1962 as a young aeronautical engineer
and quickly became involved in two of the seminal projects of modern
flight, the X-15 and the lifting bodies. In the process, he pioneered
(with Lawrence Taylor) the application of digital computing to the
reduction of flight data, arriving at a method known as parameter
estimation, now applied the world over. Parameter estimation not only
enabled researchers to acquire stability and control derivatives from
limited flight data, but in time allowed them to obtain a wide range of
aerodynamic effects. Although subsequently involved in dozens of
important projects, Dr. Iliff devoted much of his time and energy to
hypersonic flight, embodied in the Shuttle orbiter (or as he refers to
it, the world s fastest airplane). To him, each Shuttle flight,
instrumented to obtain a variety of data, represents a research
treasure trove, one that he has mined for years. This book, then,
represents the story of Dr. Ken Iliff s passion for flight, his work,
and his long and astoundingly productive career. It can be read with
profit not just by scientists and engineers, but equally by policy
makers, historians, and journalists wishing to better comprehend
advancements in flight during the second half of the twentieth century.
Dr. Iliff's story is one of immense contributions to the nation s
repository of
Document ID: 20040077335
424-pages

http://ntrs.nasa.gov/archive/nasa/ca...004080570..pdf

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Rusty

Rusty wrote:

Woot Woot!!!

NASA-TN-D-8136; H-905 , 19760101; Jan 1, 1976
NASA Technical Memorandum , 1989-08-01
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Thanks, Rusty -- much to chew on here!

/dps