Structural Concepts and Aerodynamic Analysis for Low Radar Cross Section (LRCS) Fuselage Configurations

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STRUCTURAL CONCEPTS AND AERODYNAMIC ANALYSIS FOR
LOW RADAR CROSS SECTION (LRCS) FUSELAGE CONFIGURATIONS
David W. Lowry, Melvin J. Rich, Saul Rivera, Thomas W. Sheehy
00 Sikorsky Aircraft Division
ILO United Technologies Corporation
Stratford, Conn. 06603
I • 	D D C
4. July 1978 	SEP 191918
SFinal Report
LAJ
Approved for public release;
C distribution unlimited.
Prepared for
APPLIED TECHNOLOGY LABORATORY
U. St. ARMY RESEARCH AND TECHNOLOGY LABORATORIES (AVRADCOM)
Fort Eustis, Va. 23604 	,.i
,44, 	, 
.,. 4  
APPLIED TECHNOLOGY LABORATORY POSITION STATEMENT
This report provides a study of fuselage concepts for three low radar cross section
aircraft configurations. An assessment of these concepts in terms of cost, weight, safety,
advanced materials, risk, maintainability and aerodynamic performance was made, including
comparisons with the UH.60A helicopter.
The three LRCS configurations were developed by the Applied Technology Laboratory.
The study was conducted by Sikorsky Aircraft Division of United Technologies Corpora.
tion under Contract DAAJ02-76-C-0062.
Mr. Bill W. Scruggs, Jr., of the Military Operations Technology Division served as project
engineer for this effort,
OISCLAIMEri5
The findinqs in this report ar- not to be monstrmed as an nlf,ciml Detiertmarnt of the Armmy position unless so
designated by other authorited documinernts.
When Oovernmentr drawlrtis ýptieificatirlrs, or other data owr used for any purpose other than In connection
with a definitely related GOviirnmernt procurement operation, the United Statat Govwnrnmant thereby Incurs no
rersponsibility not riny ohlir.tiirr whottnvypr' end the fect that thm tjovernrenht may hivin formulated, iurniahed,
or in any way supplied lie taid irewmvin%, srricifw.atlon-ý, ur oithe; t'tita ,s i1t to ho reorierdd by ir"pl'catlorn Or
otherwlse 1m in tny ,'namner lir:rinsinrt the hrildor or any tither person or cen. uorntion, or ronvoylnq aily rights or
13arrnmi$,on, to mnrtim, ? chir,? ust' ur Se, I Anry i nvo thtwl livit f iii tthrilt rtay ,, any Wvgy bit 10Iitad theetO.
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"--141TY CLASSIFICATION OF THIS PAGE(Wh.., 11816 nfffoed)
configuration; (5) to identify high tenchnical risk areas; (6) to develop over-
all design tranding data for helicopters, usinq the three fuselage configura-
tions of conventional and advanced materials; U7) to conduct an analytical
investigation of the aerodynamic loads, vertical drag and mission performance 0
the three low radar cross section (LRCS) configurations ; and (8) to compare the
findings with those of the baseline UH-60 helicopter.
Structural concepts developed for the three LECS configurations showed that
extensive reshaping, as exemplified by Configuration 2, would increase fuselage
weight from that of the baseline UH-60A fuselage by 223 pounds and cost by
3.65 percent. When advanced materials were used Configuration 2 decreased
from the baseline fuselage weight and cost by 116 pounds and 3.98 percent
respectivdly. Total aircraft performance capability was degraded primarily by
drag effects. The aerodynamic analysis indicated that Configuration 2 would
have .a vertic climb rate at 15 percent of the baseline. Since drag is a
function of ar a and shape, the weight savings of advanced materials had
negligible eff cts on performance. Weight, cost, and performance penalties
were less in Configurations 3 and 1 "espectively.
Unclassiffied
SICURtTY CLASSIFICATION OF THIS PAOE(WI"en befI Snfowe.tJ  
PREFACE
This study of structural concepts for low radar cross section (LRCS)
fuselages was conducted under Contract DPAJ02-76-C-0062 with the Applied
Technology Laboratory, U. S. Army Research and Technology Laboratories
(AVRADCOM), Fort Eustis, Virginia.
The work was performed under the general direction of Mr. Bill Scruggs,
Jr., of the Military Operations Technology Division. Sikorsky Aircraft
principal participants were Melvin Rich, Project Manager; David Lowry,
Structural Concepts; George Howard, Helicopter Design; Anthony Dipierro,
Weights Engineering; lieville Kefford, Helicopter Design Modeling;
Brian Carnell, Survivability; and Calvin Holbert, Reliability and
Maintainability.
An analytical investigation of the aerodynamic loads, drag and mission
performance of low radar cross section configurations was performed by
Mr. Saul Rivera, Aerodynamicist, under the direction of Mr. Thomas W.
Sheehy, Aerodynamicist, both of Sikorsky Aircraft.
Acc3.,oN for
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TABLE OF CONTENTS
PAGE
PREFACE ................. ...... 3
LIST OF TLLUTRATIONS ..A.I. ......... ................... 7
LIST OF TABLES. ........ ..................11
INTRODUCTION .................... .. 	13
BASELINE UTTAS FUSELAGE CONFIGURATION. ..............15
Description ... .. .. .0. .. .. .. .. .. .. ..... 15
Baseline Fuselage Wcight and Cost .............. 	16
LOW RADAR CROSS SECTION CONFIGURATIONS .... ........... 21
Configuration 1 .. .......... .... .. 21
Configuration 2. .......................21-
Configuration 3 ..............	22
PRELIMINARY DESIGN CONCEPTS (CONVENTIONAL MATERIALS). .......29
Weight Analysis. .... ... ...	.......... 29
Cost Analysis. .............. .. .......35
APPLICATION OF DESIGN CONCEPTS TO LOW RADAR CROSS SECTION FUSELAGES 39
Configuration 1 ...... ........................ 	39
Configurations 2 and 3 ...................... 	39
DESCRIPTION OF EVALUATION FOR FAIL-SAFETY, SAFETY AND MAINTAIN-
S~~~~~ABILITY 
.................. .3
i:Fail-Safety 	....................... ...3
Crash Safety/Safety .............
Maintainability. ... .. .. .. .. .. .. .. ....... 43i
MODIFICATION OF CONFIGURATION 2 .:........ ....
SELECTED CONCEPTS .B.E............... 	. . .48  
TABLE OF CONTENTS (Cont.)
PAGE
ADVANCED MATERIAL APPLICATION ........... .................*.. 49
F'ranes ................. ........................... ..49
Beams and Interoostals ...... ......... .. I ......55
Skins ................... .......................... ....55
Stringers ................. ......................... ...55
ADVANCED MATERIAL APPLICATION COSTS .................... .. 56
HELICOPTER DESIGN MODEL .............. .................... ... 63
Introduction .......................63
HDM Results ............ .... .	. 63
TECHNICAL RISKS ............... .............. ..... ... 68
CONCLUSIONS ............................... .... ........ 69
REFERENCES ..................... .......70
APPENDIX A, AERODYNAMICS ANALYSIS OF LOW RADAR CROSS SECTION
CONFIGURlATIONS ................S............ ...71
LIST OF SYMBOLS ........... ................... ...... 138
6,  
LIST OF ILLUSTRATIUNS
FIGUNE 	PAGE
1 PROGRAM STUDY FLOW CHART ................. 	1
4
2 GENERAL ARRANGEMENT OF UH60A ............... 	17
3 GENERAL ARRANGEMENT OF LRCS CONFIGURATION 1. ........ 23
4 GENERAL ARRANGEMENT OF LRUS CONFIGURATION 2 ............ ... 25
5 GENERAL ARRANGLMENT OF LRCS CONFIGURATION 3 ............ ... 27
6 STRUCTURAL CONCEPTS A, B AND C....... 	30
7 BODY GROUP WEIGHT VERSUS BODY GROUP WEIGHT PARAMETERS ... 32
8 ADVANCED MATERIALS APPLICATION FOR CONFIGURATION 2 ...... 51
9 ADVANCED MATERIALS APPLICATION FOR CONFIGURATION 3 ........ 53
10 PAYLOAD AND RANGE FOR LOW RADAR CROSS SECTION HELICOPTERS.. 67
A-I GEOMETRICAL REPRESENTATION OF THE UH6OA FUSELAGE(BASELINE) . 82
A-2 GEOMETRICAL REPRESENTATION OF THE UH6OA WITH MAIN ROTOR
PYLON (BASELINE) ...................... 83
A-3 GEOMETRICAL REPRESENTATION OF THE LRCSI FUSELAGE ...... 8(4
A-4 GEOMEWRICAL REPRESENTATION OF THE LRCSI FUSELAGE WITH
BASELINE MAIN ROTOR PYLON ..................... 	85
A-5 GEOMETRICAL REPRESENTATION OF THE LRCS2 FUSELAGE ...... 86
A-6 GEOMETRICAL REPRESENTATION OF TIE LRCS2 FUSELAGE WITH
BASELINE MAIN ROTOR PYLON ........ .................. ... 87
A-7 GEOMETRICAL REPRESENTATION OF THE LRCS3 FUSELAGE ...... 88
A-8 GEOMETRICAL REPRESENTATION OF THE LRCS3 FUSELAGE WITH
BASELINE MAIN ROTOR PYLON ........ ................. .... 89
A-9 COMPARISON OF THE Ui16OA AND LRCSI CALCULATED SURFACE
PRESSURES, TOP CENTEMLINE, = 00, $ 00 .... . .90
A-10 COMPARISON OF THE UH60A AND LRCS1 CALCULATED SURFACE
PRESSURES, BOTTOM CENTERLINE, = 00, = 00 ...... .. 91
7  
LIST OF ILLUSTRATIONS (cont.)
FIGURE 	PAGE
A-11 COMPARISON OF THE UH6oA AND LRCSl CALCULATED SURFACE
PRESSURES, LATERAL CENTERLINE, c = 0o, 4J 00 .......... 92
A-12 COMPARISON OF THE UH60A AND LRCSi CALCULATED SURFACE
PRESSURES, TOP CENTERLINE, a.
40
, 'QO ............. 93
A-13 COMPARISON OF THE UH60A AND LRCS. CALCULATED SURFACE
PRESSURES, BOTTOM CENTERLINE,  m 40, 00 .0O, 	94
A-14 COMPARISON OF THE UH60A AND LRCSI CALCULATED SURFACE
PRESSURES, LATERAL CENTERLINE, a -40, ' 00. .............95
A-15 COMPARISON OF THE UH60A AND LRCS1 CALCULATED SURFACE
PRESSURES, TOP CENTERLINE, as 80, 00 = .0° ..... ... 96
A-16 COMPARISON OF THE UH60A AND LRCSl CALCULATED SURFACE
PRESSURES, BOTTOM CENTERLINE, a a 80, * 00.. .......... 97
A-17 COMPARISON OF THE UH60A AND LRCS1 CALCULATED SURFACE
PRESSURES, LATERAL CENTERLINE, a = 80, 4 = 00 ..	98
A-16 COMPARISON OF THE UH60A AND LRCSl CALCULATED SURFACE
PRESSURES, TOP CENTERLINE, 	.= -4, p 0 ..... .... 9
A-19 COMPARISON OF THE UH60A AND LRCSI CALCULATED SURFACE
PRESSURES, BOTTOM CENTERLINE, a -40, 'p .0 .... i..00
A-20 COMPARISON OF THE U160A AND LRCSI CALCULATED SURFACE
PRESSURES, LATERAL CENTERLINE, a -_40, 00 = o. •..... I...
A-21 COMPARISON OF THE UH60A AND LRCSJ. CALCULATED SURFACE
rnN-..xs TorENT--L-N°,) p = .. ..... 1. 2
A-22 COMPARISON OF THE Un6OA AND LRCSI CALCULATED SURFACE
PRESSURES, BOTTOM CENTERLINE, a -6
0
, p = 00 ...
A-23 COMPARISON OF THE U1160A AND LRCS1 CALCULATED SURFACE
PRESSURES, LATERAL CENTERLINE, -8, p 0°. ......... 10
A-24 COMPARISON OF T}lE Ul16OA AND LHCS2 CALCULATED SURFACE
PRESSURES, TOP CENTERLINE, a = 00, 00 ......... 05
A-25 COMPARISON OF THE UH60A AND LRCS2 CALCULATED SURFACE,
PRESSURES, BOTTOM CENTERLIWE, Q 00, 00 .°. ......
A-26 COMPARISON OF THE U1160A AND LIRC2 CALCULATED SURFACE
PRESSURES, LATFRAL CENTERLINE, a = 0°, 00 = 0 ..... 107
8  
LIST OF ILLUSTRATIONS (cont.)
FIGURE 	PAGE
AI-27 COMPARISON OF THE UH60A AND LRCS2 CALCULATED SURFACE
PRESSURES, TOP CENTERLINE, -40, 0 .0.... .... ... 108
A-28 COMPARISON OF THE UH60A AND LRCS2 CALCULATED SURFACE
PRESSURES, BOTTOM CENTERLINE, a = 0 .0. ...... ..109
A-29 COMPARISON OF THE UH60A AND LRCS2 CALCULATED SURFACE
PRESSURES, LATERAL CENTERLINE, a= 40, 0 = .
0.  . . .. 
110
A-30 COMPARISON OF THE UH60A AND LRCS2 CALCULATED SURFACE
PRESSURES, TOP CENTERLINE, a = 80, ' 00 ...... . I.. i
A-31 COMPARISON OF THE UH60A AND LRCS2 CALCULATED SURFACE
PRESSURES, BOTTOM CENTERLINE,  = 80, ' 00. ...... . 112
A-32 COMPARISON OF THE UH6oA AND LRCS2 CALCULATED SURFACE
PRESSURES, LATERAL CENTERLINE, c- 80, 4 00 .... ... .113
A-33 COMPARISON OF THE UH60A AND LRCS2 CALCULATED SURFACE
PRESSURES, TOP CENTERLINE, -4 -04, 4 -00 ..... .... . 114
A-34 COMPARISON OF THE UH60A AND LRCS2 CALCULATED SURFACE
PRESSURES, BOTTOM CENTERLINE, a --40, 4' 00 ......115
A-35 COMPARISON OF THE UH60A AND LRCS2 CALCULATED SURFACE
PRESSURES, LATERAL CENTERLINE, -40, = 00 ....... 116
A-36 COMPARISON OF THE UH60A AND LRCS2 CALCULATED SURFACE
PRESSURES, TOP CENTERLINE, -0 = °, 4 = 00. ....... i17
A-37 COMPARISON OF THE UH60A AND LRCS2 CALCULATED SURFACE
PRESSURES, BOTTOM CENTERLINE, a = -80, 00 = 0. ........
A-38 COMPARISON OF THE UH60A AND LRCS2 CALCULATED SURFACE
PRESSURES, LATERAL CENTERLINE, --80, 00. ..... 119
A-39 COMPARISON OF THE UH60A AND LRCS3 CALCULATED SURFACE
PRESSURES, TOP CENTERLINE, ai= 
0
, = 0 00 ........ .... 120
A-40 COMPARISON OF THE UHbOA AND LRCSJ CALCULATED SURFACE
PRESSURES, BOTTOM CENTERLINE, 0 = 0°, ........ . 121
A-41 COMPARISON OF THE UH60A AND LRC83 CALCULATED SURFACE
PRESSURES, LATERAL CENTERLINE, c 0 = 0, 0 = ..... 122
A-42 COMPARISON OF THE UH60A AND LRCS3 CALCULATED SURFACE
PRESSURES, TOP CENTERLINE, = 
40, = 00 .... .. ... 123
9
... ...... I 	~ .~il~l~ 41 .Ahi~lftlL\AL  
LIST OF ILLUSTRATIONS (cont.)
FIGURE 	PAGE
A-13 COMPARISON OF THE UH60A AND LRCS3 CALCULATED SURFACE
PRESSURES, BOTTOM CENTERLINE, = 4 4, 00. ..... ..
A-44 COMPARISON OF THE UH6oA AND LRCS3 CALCULATED SURFACE
PRESSURES, LATERAL CENTERLINE, ot = 4'1, .= 0°. ......... 5.
A-45 COMPARISON OF THE UH60A AND LRCS3 CALCULATED SURFACE
PRESSURES, TOP CENTERLINE, 80, 00 = 0.. ...... .26
A-46 COMPARISON OF THE UH60A AND LRCS3 CALCULATED SURFACE
PRESSURES, BOTTOM CENTERLINE, 8, = 00 ... 12..
A-47 COMPARISON OF THE U160A AND LRCS3 CALCULATED SURFACE
PRESSURES,. LATERAL CENTERLINE, c = 80, 4 = O0.. ...... 128
A-48 COMPARISON OF THE UH60A AND LRCS3 CALCULATED SURFACE
PRESSURES, TOP CENTERLINE, = -4
0
, 0O .... 129
A-49 COMPARISOIN OF THE UIH60A AND LRCS3 CALCULATED SURFACE
PRESSURES, BOTTOM CENTERLINE, = -4
0
, 4 = 00. ... 130
A-50 COMPARISON OF THE UH60A AND LRCS3 CALCULATED SURFACE
PRESSURES, LATERAL CENTERLINE, 	0= 04, = .o. ... .31
A-51 COMPARISON OF THE UH60A AND LRCS3 CALCULATED SURFACE
PRESSURES, TOP CENTERLINE, a=-80, 
0
0 .. .. 132
A-52 COMPARISON OF THE U1t60A AND LRCS3 CALCULATED SURFACE
PRESSURES, BOTTOM CENTERLINE, -8u, 0). ....133
A-53 COMPARISON OF THE UH60A AND LRCS3 CALCULATED SURFACE
PRESSURES, LATERAL CENTERLINE, 	008o, 1 3 )1
A-54 VARIATION OF LIFT WITH ANGLE OF ATTACK FOR THE UH6OA,
LRCS1, 1RCS2, LRCS3 CONFIGURATIONS ........ 	... 13
A-55 VARIATION OF DRAG WITH ANGLE OF ATTACK FOR nIE UH6OA,
LRCSI, LRCS2, IRCS3 CONFIGURATIONS ............ ....... .136
A-56 VARIATION OF PITCHING MOMENT WITH ANGLE OF ATTACK FOR T.LE
UIn6OA, LRCS1, LRCS2 AND LRCS3 CONFIGURATIONS .......137
10  
LIST OF TABLFS
TABLE 	PAGE
1 BASELINE UH60A FUSELAGE WEIGHT AND COST DATA .......20
2 BASELINE FUSELAGE SKIN/STRINGER WEIGHT FROM WEIGHT AND 34
BALANCE REPORT .................. .....................
3 CONFIGURATION 2A AND 2B SKIN/STRINGER WEIGHT ..... .... 34
4 CONFIGURATION 3A AND 3B SKIN/STRINGER WEIGHT .... 	35
5 CONFIGURATION 2C HONEYCOMB PANEL SKIN WEIGHT .... 37
6 CONFIGURATION 3C HONEYCOMB PANEL SKIN WEIGHT .... 	37
7 CONFIGURATION I FUSELAGE WEIGHT AND COST DATA ......... 39
8 CONFIGURATION 2A FUSELAGE WEIGHT AND COST DATA .4
9 CONFIGURATION 2B FUSELAGE WEIGHT AND COST DATA ..
10 CONFIGURATION 2C FUSELAGE WEIGHT AND COST DATA .... .41
11 CONFIGURATION 3A FUSELAGE WEIGHT AND COST DATA .... . 41
12 CONFIGURATION 3B FUSELAGE WEIGHT AND COST DATA .42
13 CONFIGURATION 3C FUSELAGE WEIGHT AND COST DATA . 42
14 SAFETY AND CRASH-SAFETY RANKING. . ...... . 45
15 SUMMARY OF FUSELAGE WEIGHT AND COST DATA OF CONVENTIONAL
CONSTRUCTION ........... ...................... 	46
16 FLOOR WEIGHT COMPARISON FOR CONFIGURATION 2 ..... 47
17 COCKPIT STRUCTURAL WEIGHT ...... ................. 57
18 COCKPIT STRUCTURAL WEIGHT OF CONFIGURATION IA OF CONVEN-
TIONAL MATERIALS AND ADVANCED MATERIALS ... .......... 58
19 COCKPIT STRUCTURAL WEIGHT OF CONFIGURATION 2A OF CONVEN- 59
TIONAL MATERIALS AND ADVANCED MATERIALS .... .........
20 COCKPIT STRUCTURAL WEIGHT OF CONFIGURATION 3A OF CONVEN- 6o
TIONAL MATERIALS AND ADVANCED MATERIALS ........
21 CONFIGURATION I ADVANCED MATERIALS FUSELAGE WEIGHT AND 61
COST DATA ...... .......................
11  
LIST OF TABLES (cont.)
TABLE 	PAGE
22 CONFIGURATION 2 ADVANCED MATERIALS FUSELAGE WEIGHT AND 61
COST DATA ..... .. ... .. ... .. ... ..
23 CONFIGURATION 3 ADVANCED MATERIALS FUSELAGE WEIGHT AND 62
COST DATA ......... ...............
24 SUMMARY OF WEIGHT AND COST DATA FOR CONCEPT A AND 	62
ADVANCED MATERIALS.......... ............
25 PRELIMINARY DRAG ESTIMATE ................ 	64
26 HELICOPTER DESIGN MODEL CONSTANT GROSS WEIGHT RESULTS. . 65
27 HELICOPTER DESIGN MODEL TRENDING RESULTS .. . ... 66
A-I UH-60A VERTICAL DRAG CALCULK2ION........ ...... 76
A-2 LRCS I VERTICAL DRAG CALCULATION. ........... 77
A-3 LRCS 2 V ETICAL DRAG CALCULATION ....., ...... 78
A-4 LRCS 3 VERTICAL DRAG CALCULATION. ....... .... 79
A-5 SUMMARY OF PARASITE AND VERTICAL DRAG .... ..... 80
A-6 PRIMARY MISSION PERFORMANCE SUMMARY .......... 81
12  
INTRODUCTION
The objectives of this study were: (a) to develop structural concepts
and determine their effects on weight, cost, fail-safety and maintain-
ability for th.ree low radar cross section fuselages constructed of con-
ventional materials, and to compare these to a baseline Sikorsky Utility
Tactical Transport Aircraft System (UH60A) helicopter; (b) based upon
the results of the study to select the structural concept for the three
configurations that is the lowest in weight and cost, and is the easiest
to maintain; (c) to assess the application of advanced materials for each
configuration; (d) to develop design trending data for helicopters, using
the three configurations of conventional and advanced materials' and
(e) to identify high technical risk areas.
Three fuselage configurations for low radar cross sections were developed
by the Applied Technology Laboratory. Mold line drawings of each
configuration were provided by the Army for this study. The main rotor
pylon fairings and tail surfaces aft of a tail fold hinge for each
configuration were the same as those for the baseline UH6OA.
In the initial portion of this study, the weight and costs (percent of
total) were developed for sections of the baseline UH6OA fuselage.
General arrangement drawings of each configuration were developed from
the mold line drawings. Structural concepts were developed which could
be applied to each configuration using conventional materials. An
assessment of safety, fail-safety, and maintainability for each configu-
ration was performed. The change in structural weight and the percentage
change in cost for each configuration using the concepts developed were
compared to those of the baseline. One concept was selected and applied
to the three configurations.
Having selected the structural concept with the lowest weight change and
percentage cost change for the three fuselage configurations, the effect
on weight and costs using advanced materials was developed and applied to
the three configurations.
To evaluate the impact of the results of the fuselage study, design
attributes of six helicopters were developed using a Helicopter Design
Model (HDM) computer program.
The six helicopters (three of conventional materials and three of advanced
materials) were compared to the baseline UH60A. Technical risks were
assessed.
The approach to this study is illustrated on the flow chart of Figure 1.
A detailed analytical aerodynamic investigation of the fuselage
configurations was undertaken at the conclusion of the above study. The
results of this additional work are reported in Appendix A.
13  
C.))
HH
191  
BASELINE Un60A 1USELA3E CONFIGURATION
DESCRIPTION
The baseline fuselage of this study, shown in Figure 2, is that of the
Sikorsky UH-60A. The fuselage is made up of six major sections:
1. Cockpit (or nose)
2. Mid-cabin
3. Aft-cabin (or transition)
4. Tail cone
5. Pylon
6. Stabilizer
The cockpit section is a molded fiberglass/epoxy framework above the floor.
The framework supports the windshields, doors, and overhead controls.
Structure below the floor is of built-up aluminum beams and frames. The
structure supports the pilot and copilot seats, flight controls and
electronic equipment.
The cockpit section is of double contour with many cutouts and supports
for a variety of equipment.
The mid-cabin section is of forged and built-up aluminum frames and beams.
The mid-cabin consists of an upper section, two side sections, a tub
section and a combination walking cargo floor. The entire section
supports the engines, transmission, flight controls, troop seats, litters,
cargo and the main landing gears.
The aft-cabin section, double contoured, is of' honeycomb sandwich bulk-
heads, aluminum inturcostals, stringers and skins. This section supports
two fuel cells and a small cargo deck.
The tail cone is constructed of bent-up aluminum frames which support
rolled formed stringers and aluminvm sheet skins. The tail cone is a
single-wrapped contour where the skin/stringer combination is riveted to
floating frames. Floating frames do not have a direct shear tie to the
skins. The tail cone supports the tail rotor drive Lshaft, tail landing
gear and the tail pylon fold hinges.
The pylon and the stabilizers are airfoil shaped structures of built-up
spars, formed ribs and formed stiffeners covered with aluminum sheet
skins. The pylon supports the tail rotor and gearbox. The stabilizers
provide pitch control for the helicopter.
15  
BASELINE FUSELAGE WEIGHT AND COST
The structural weights of the six sections of the baseline fuselage were
obtained from the actual weight and balance report for the UH-60A
(Reference 1).
The costs of the six sections of the baseline fuselage were obtained from
a cost/weight relationship study conducted by Sikorsky Aircraft after the
detail design of the UH60A aircraft had been completed.
The costs were determined for materials and labor for each section of the
baseline fuselage, based on the production of 276 fuselages. The costs
reflect 1977 pricing.
Material costs included purchased items such as formed stringers, rolled
sheet stock, extruded shapes, forgings and windshields. The total
material costs required to produce each section of the baseline fuselage
were given in terms of dollars per pound of structural weight of the
section. The material costs ranged from a low of approximately $2.00 per
pound to a high of approximately $10.00 per pound.
Labor hours required to fabricate each section were determined as follows:
1. Fabrication of individual structural elements that make up
frames, beams, bulkheads, fittings, stringers, intercostals,
longerons, and floors.
2. Assembly of the structural elements to produce frames, beams,
etc.
3. Installation of frames, etc., to produce a structural section of
the fuselage.
Labor costs were based on $22.50 per hour.
No tooling, engineering, or development costs were considered. It should
be noted that tooling costs are relatively small for production heli-
copters (less than 3 percent- Reference 2).
i. UH-60A VOLUME 3, PART 1-III WEIGHT AND BALANCE dated September 27,
1976.
2. Rich, M. J., INVESTIGATION OF ADVANCED HELICOPTER STRUCTURAL DESIGNS,
VOLUME 1 -ADVANCED STRUCTURAL COMPONENT DESIGN CONCEPTS STUDY,
Sikorsky Aircraft Div., USAAMRDL-TR-75-59A, U.S. Army Air Mobility
Research and Development Laboratory, Fort Eustis, Va. 23604, May
19Th, AD AO262h6.
16
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FIGURE 2. * GENlrA AiRANGD4D OF uU60 A
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M592 (2ML2, -.------ -
11 8L...... ,3.____
kLECTRI 	-3-390-i 	(32ee.8). -. ------- 	T .-- 	- -	AIL R~O 6Rj%
7UP 
NGIF MNES- 
\
STA
....	STA / .
664,376
-- --- ----
E_ 0 FTTCG0hIN- 
- CJGI
I0,6R -HEE BAS 34775 2811LPJ~4NGGEARCI~40' 	S
.	-OVE.ALL LEGH..(4I~.........-...  
".IAN OETER r644' (53e)
BLADES 
4CHORD 	1.73'/ 175'
AIRFOIL 	SCIO95/SCIO95R8
BLADE AREA 1868 FT
8
SOLIDITY 
6
TIP SWEEP 92... ..... 	.- 'TW 	IST -le'
... ....... 	.... 	BLA.ES 41 1T
CHORD 	.81 FT
AIRFOIL 	SC1095
172.6' 
BLADE AREA 17.8? FT'
(I4i4') 	SOLIDITY J875
. L 45. 	TWIST -le
L .86.. 	AREA 	4.8 FT
ROOT CHORD 44 IN
TIP CHORD 3p .5 IN
?OOA 	SWEEP A CHORD
ASPECT RATIO 4.6
..... ... .	AIPFCAI 	NArA 0014
INCIDENCE/DIHEDRAL
'  	~SPAN 	a,.9'8'
-A/ 	I32 (iId),
I u.. (AIROO DI' 	AREAL 32.PT.... .......... .. TAIL ..D. 	ROOT CHORD LOWEP 72 IN
-WL339.15 	TIP CHORD LOWER 5eIN
ROOTCHORDUPPER 45IN
.. 324.729TIP 	CHORD UPPER 341N
WLY9 6.3 	SWEEP I14 CHORD 41
ASPECT RATIO 1.921,, 
AIRFOIL MOO OF) NACA 0021 MODIFED
--LANDIfG GAR_.A_.. MAIN TAl
I 	LOCATION.STATION 297.25 645
.BUTTLINE 5Wo 0STAm( ,R,,",' ."OLLING 
RADIUS 10.6IN
6~4.?6 /FLAT 	TIRE RADIUS 7, N 4.5 IN
OUTSIDE UIIAMETER 26.00 IN 17.5 IN
--WL 2A4A -TIRE 	WIDTH 9.5 IN GC3 IN' ' 	IRE SIZE 26 X 9.5-11 6O0,6
S~17OO 20
/T ,12tI
.., ...
"VATIC GRUND LINE 	Iwir-
LANDING GEAR CMPESSED
... ..W~l, 238,949  
ANN N. Niw
"6- 	AWN 	0~	GENERAL ARRANGEMNT
"UHBGOA
0 50 100
.1 	-A
------i,u~~~~~~~~~~. ...... .............. 	,,  ,.. .. 	 ., "-q.... ..