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APPENDIX A: THE CAMRAD MODEL
OF THE XV-15/ATB
Airframe/Rotor Model
The namelist input data for the XV-15/ATB are given
below for airplane mode. The nominal blade configuration
is 1° sweep and fully twisted tips, with Boeing's
aerodynamic-center offsets. Alternative data for 0° sweep,
zero-twist tips, and zero offset are included as comment
fields. Other comments note changes to the C97 model,
several of which were suggested by Wayne Johnson.
Page numbers refer to the CAMRAD/JA User's Manual
(ref. 5).
The namelists have been simplified and reformatted
for publication. Certain unused inputs (identically equal to
zero) have been deleted. CAMRAD can regenerate namelists
from binary data, and most of the data given below
have been left in the default output format. The number of
significant figures is, therefore, neither consistent nor
meaningful, being determined by FORTRAN output
conventions and the data-storage specifications of the
computer code.
CAMRAD/JA users should be aware that there are
two different XV- 15 aircraft. Only aircraft S/N 703,
operated by NASA, has been flown with the ATBs. Both
aircraft have "lateral cyclic (trim) bias" (CNTRLZ(2)
and CNTRLZ(5)), effective in helicopter mode, and
"longitudinal cyclic (trim) bias" (CNTRLZ(3) and
CNTRLZ(6)), effective in airplane mode. Aircraft S/N
702, operated by Bell, also has a "flapping controller" that
uses lateral cyclic in airplane mode. The published
literature does not consistently distinguish between these
three trim inputs; any of them may be referred to as
"flapping control." Users should also be aware that GTRS
(ref. 11) uses a reference wing area of 181 ft 2, whereas
the standard CAMRAD model uses 169 ft 2.
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