Lee, J. B.

English

NASA Technical Reports Server

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RESEARCH MEMORANDUM 
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a INVESTIGATION OF m C T I O N  RELEASES OF AN MB-1 ROCKET 
mk FROM A 0 . O ~ ~ ~ ~ - S C A L E D  MODEL OF TIIE CONVAIR 
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F-106~ AIRPLANE AT MACH mUMBER 1.59 
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elma C O O -  NO. AF-AM-5'7 
- Sy John B. Lee 
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1 
NATIONAL ADVISORY COMMITTEE I 
Restriction/Classification 
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NACA RM SL57E07 - 
NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS 
RESEARCH MEMORANDUM 
f o r  the 
U. S. A i r  Force 
INVESTIGATION OF EJECTION REIXASES OF AN MB-1 ROmT 
FROM A 0.04956-S~AIX~ MODEL OF TRE ' C O N V D  
F-106~ AIRPLANE AT. MACH NUMBEB 1.59 
COORD. NO. AF-AM-57 
By John B. Lee 
SUMMARY 
An investigation has been conducted i n  the 27- by 27-inch pref l ight  
. j e t  of the Langley Pi lo t less  Aircraft  Research Stat ion a t  Wallops Island, 
Va., of the ejection release character is t ics  of the MB-1 rocket from the 
missile bay of a 0.04956-scaled model of the Convair F-106~ airplane. 
Y 
The MB-1 rocket w a s  ejected with i t s  f i n  t i p s  retracted,  f o r  a simulated 
a l t i tude  of 18,670 f e e t  at a Mach number of 1.59. 
Successful ejections were made with the MB-1 rocket a t  supersonic 
speeds by applying a proper combination of e ject ion velocity and nose- 
down pitching moment to  the rocket a t  release.  The pitching moment a t  
release required t o  keep the MB-1 rocket a t  a near leve l  a t t i tude  a f t e r  
release was influenced by the presence and number of Falcon missiles i n  
the missile bay. 
INTRODUCTION 
A t  the request of the U . S . Air Force, an investigation w a s  made to 
determine the eject ion character is t ics  of an in te rna l ly  carried MB-1 rocket 
from the missile bay of a model of the Convair F -106~  airplane. To carry 
the rocket i n  the F - ~ O ~ A ,  the f i n  t i p s  are  retracted inside the f i n s  with 
the f i n  t i p s  telescoping out upon the f i r i n g  of the rocket. It is required 
tha t  the rocket be a t  near leve l  f l i g h t  upon the f i r i n g  of the rocket motor 
NACA RM SL37E07 - 2 
and the extension of the f i n  t i p s .  Adverse pitching moments of a s tore  
B* 
b *  
due t o  aerodynamic forces, i n  the v ic in i ty  of the missile bay and fuse- 
B *** lage, may endanger the airplane. It was thus necessary t o  investigate 
D o  me 
D O  the release character is t ics  of the rocket and develop an eject ion method 
B  
D  .* 
that would give the desired rocket a t t i tude  a t  the ins tan t  of rocket 
D .  
D * O  . f i r ing .  This investigation included a study of the rocket with f i n s  
retracted only. An ejector  was designed that would impart an i n i t i a l  
pitching moment to  the rocket at  release tha t  would overcome any adverse 
pitching. 
In  reference 1, from a comparison of s t a t i c  and dynamic t e s t s ,  there 
were strong indications tha t  model t e s t s  should include a l l  pertinent 
de ta i l s  of the ful l -scale  bomb bay. Additional investigations of dynamic 
models ( refs .  2 and 3)  also showed t h i s  t o  be t rue.  The missile bay of 
the F-106~ i s  designed t o  carry up to four Falcon missiles with the MB-1 
rocket. This investigation included these Falcon missiles with t h e i r  rail  
launchers. The ef fec ts  of several missile bay configurations with and 
without Falcon missiles were investigated. 
The models were dynamically scaled by the light-model method as  out- 
l ined i n  reference 4. The models simulated an a l t i t ude  of 18,670 f e e t  a t  
a Mach number of 1.59 with a Reynolds number of approximately 11.3 x 10 6 
per foot. This investigation w a s  made with a 0.04956-scaled model i n  the 
pref l ight  j e t  of the Langley Pi lo t less  Aircraft  Research Stat ion a t  
Wallops Island, Va.  
diameter, 0.859 in.  f o r  rocket missile 
rocket model length, in.  
Mach number 
equivalent ful l -scale  applied moment a t  rocket release, 
posit ive nose up, f t - l b  
number of Falcon missiles i n  missile bay 
radius, in .  
time, sec 
time in terva l  of stroboscopic photographs, sec 
NACA RM SL57E07 '- 3 
x horizontal distance of rocket model center of gravity with 
or igin a t  point of release, posit ive downstream, in .  
z ve r t i ca l  distance of rocket model center of gravity with 
or igin a t  point of release, posit ive down, in .  
;o ejection velocity of rocket model a t  point of release, f t / s ec  
angle of attack of airplane fuselage, deg 
@M rocket model pi tch angle i n  reference t o  undisturbed free-  
stream direction, deg 
- MODEIS AND APPARATUS 
MB-1 Rocket 
A photograph and a sketch of the MB-1 rocket with retracted f i n  
t i p s  are  shown i n  figure 1, and the rocket model ordinates are  shown i n  
table I. To s tore  the rocket i n  the missile bay of the fu l l - sca le  a i r -  
plane, with Falcon missiles,  the MB-1 f i n  t i p s  a re  retracted in to  t h e i r  
respective f ins .  For t h i s  investigation only models with retracted f i n s  
were used. 
The MB-1 rocket has a fineness r a t i o  of 6.4 and a center-of - 
gravity posit ion of 55 percent of the rocket length from the nose. Fig- 
ure l ( b )  shows the posit ion of the ejection pins. The rocket was carr ied 
i n  the missile bay a t  a negative incidence angle of 2' with the airplane. 
A l l  t e s t s  fo r  this investigation were made a t  a fuselage angle of a t tack 
of 2O. 
A model weight of 0.201 pound and an i n e r t i a  of 0.441 pound-square 
inch simulated an a l t i t ude  of 18,670 f e e t  f o r  a ful l -scale  weight of 
800 pounds and an i n e r t i a  of 720,000 pounds-square inches. 
Fuselage and Missile Bay 
A sketch of the 0.04956-scaled model of the Convair F-106~ airplane 
used for  this investigation i s  shown i n  figure 2. The model was attached 
to  an extension of the nozzle plate  by two s t ru t s ,  one attached to each 
wing. The nose of the model extended in to  the nozzle, and the f ront  end 
of the MB-1 rocket w a s  approximately 318 inch downstream of the nozzle 
ex i t .  The airplane model was at a 2O angle of a t tack i n  the t e s t  section. 
Figure 2 shows the model s e t  up with c ~ f  = 0'. 
NACA RM SL57E07 ...\.---rrrmr 4 
.<, 
The missile bay was constructed to  carry four Falcon missiles i n  
addition to  the MB-1 rocket. The Falcon missiles were removable from 
i the model missile bay as necessary fo r  the t e s t s .  For a missile-bay 
combination of two Falcon missiles,  (Nf = 2)  the two forward Falcon 
missiles were i n  place with the two rear  Falcon missiles removed. 
Ejection Mechanism 
A n  ejector  cylinder was located d i rec t ly  above the model on the 
nozzle-top-plate extension ( f ig .  2 ( a ) ) .  The ejector  rods passed through 
protective rods tha t  connected to  the top of the airplane model. An a i r -  
pressure cylinder applied force to a crossbar ( f ig .  2 ( a ) ) .  The e jec tor  
cylinder with the crossbar could be adjusted to  apply different  forces to 
the ejector  rods t o  obtain the desired pitching moment of the rocket. 
The rocket was locked in to  the .ejector rods by pins backed by tension 
springs. The force of the ejector  rods on the ejector  pins would over- 
come the force of the tension springs and the model would be ejected. 
The ejection stroke length w a s  0.5 inch. 
Pref l ight  J e t  
This investigation w a s  made i n  the 27- by 27-inch pref l ight  j e t  of 
the Langley Pi lo t less  Aircraf t  Research Station at Wallops Island, Va. 
The t e s t  setup i s  shown i n  figure 2. A description of the tunnel i s  given 
- i n  reference 4. 
Photography 
Stroboscopic photographs were obtained by using a spinning disk with 
sl i ts  i n  f ront  of the camera lens ( re f .  2 ) .  The time in terva l  between 
frames was approximately 0.002 second. 
RESULTS AND DISCUSSION 
The purpose of t h i s  investigation was to  determine the f l i g h t  char- 
ac t e r i s t i c s  of the MB-1 rocket i n  the vicini ty  of the airplane and t o  
determine the type of release necessary to maintain a near leve l  f l i g h t  
a t t i tude .  Table I1 gives the t e s t s  and the pertinent data of each t e s t .  
Figures 3 to 6 present the stroboscopic pictures and p lo ts  of the rocket- 
- model osci l la t ions and t rajectory.  Distances divided by the maximum 
ro-cket-model diameter of d = 0.859 are shown i n  the motion plots  t o  
nondimensionalize the resu l t s .  
This investigation was made a t  M = 1.59, and an a l t i t ude  of 
18,670 f e e t  was simulated. The airplane angle of a t tack was 2' and the 
rocket incidence angle t o  the airplane w a s '  -2O. Combinations of Falcon 
missiles i n  the missile bay included Nf = 0, 2, and 4; where Nf = 2, 
the two f ront  Falcon missiles were included. Ejections were made at  
io = 23.0 t o  29.0 f e e t  per second and the pitching moment a t  release 
Mo was equivalent t o  -1,100 to  -2,000 foot-pounds, full scale.  
Figure 3 shows the e f f ec t  of changing the pitching moment a t  release 
from -2,000 to  -1,100 foot-pounds with go = 29.0 and 28.5 f e e t  per second, 
respectively, with Nf = 0. The pitching moment of -2,000 foot-pounds at 
release,  t e s t  1, was excessive and caused the MB-1 rocket to pass through 
the airstream i n  a nose-down a t t i tude .  With a decrease i n  pitching moment 
t o  -1,100 foot-pounds, t e s t  2, the rocket pi tch a t t i t ude  reached a maximum 
€lM of -lo0 a t  approximately 5 rocket diameters below the release point 
( f ig .  3(d) ) . The rocket pi tch a t t i tude  was 0' a t  10 .  s tore  diameters and 
stayed within OM = 4 O  thereaf ter .  Therefore, by regulating the pitching 
moment a t  release,  the desired pi tch a t t i tude  can be obtained to  allow the 
f i r i n g  of the missile rocket. 
Ejections of the MB-1 rocket a t  io = 28.5 f e e t  per second and 
bb = -1,100 foot-pounds with different  missile-bay combinations of Falcon 
missiles a re  shown i n  figure 4. Test 2 i s  repeated i n  figures 4(b),  ( c ) ,  
and (d)  f o r  comparison purposes. With two Falcon missiles i n  the missile 
bay, the rocket p i tch  a t t i t ude  remained within -12O f o r  10 s tore  diameters 
and then pitched to  a larger  negative angle ( t e s t  3). With four Falcon 
missiles i n  the missile bay, t e s t  4, the MB-1 rocket pitched nose up a f t e r  
release and diverged. The rocket pi tch angle, however, was l e s s  than lo0 
f o r  8 rocket diameters below the release point. Test 5 ,  made under iden- 
t i c a l  conditions, checked the resu l t s  of t e s t  4, indicating the degree of 
repeatabi l i ty  of the t e s t  technique even f o r  divergent conditions. The 
missile-bay configuration i s  thus shown to  have a large e f fec t  on the 
rocket pitching character is t ics ;  however, the rocket t ra jec tor ies  f o r  a l l  
t e s t s  remained approximately the same f o r  10 s tore  diameters. 
/ 
The greatest  change i n  release conditions appeared between missile- 
bay combinations of Nf = 2, t e s t  3, and Nf = 4, t e s t  4, with the rocket 
changing from a noseldown a t t i t ude  to  a divergent nose-up at t i tude,  
respectively. The change between Nf = 0 and Nf = 2 was small and the 
releases considered favorable, even f o r  a case of a rocket misfire. 
The e f fec t  of missile bay combinations with Mo = -2,000 foot-pounds 
on the MB-1 t rajectory i s  shown i n  figure 5. For t e s t  1, Nf = 0, and 
t e s t  6, Nf = 2, the rocket had.pitched to  -30° o r  more by the time the 
NACA RM SL37E07 
missile was 10 s tore  diameters below the release point. In  t e s t  4, 
however, with Nf = 4, the MB-1 rocket remained within BM = -11' fo r  
13 rocket diameters below the release point. 
It thus appears tha t  M, = -1,100 foot-pounds i s  suf f ic ien t  fo r  
missile bay configurations of Nf = 0 and Nf = 2 with high eject ion 
veloci t ies .  If  the missile rocket f i r e s  within 8 s tore  diameters of 
the release point, M, = -1,100 foot-pounds should a l so  be suf f ic ien t  f o r  
Nf = 4. However, an increase of pitching moment of over 80 percent, up 
t o  -2,000 foot-pounds, i s  needed to keep the rocket i n  an a t t i tude  tha t  
would not endanger the airplane i n  case of a rocket misfire.  It thus 
appears tha t  the elimination of the two rear  Falcon missiles would s i m -  
p l i f y  the release problems; tha t  i s ,  a smaller range of pitching moment 
and eject ion velocity would be needed t o  obtain good releases. 
The eject ion velocity w a s  decreased t o  23 f e e t  per second ( f i g .  6) 
with Mo = -1,170 foot-pounds. For a l l  missile-bay configurations the 
rocket pitched t o  a high posi t ive angle. The rocket remained below 
€IM = 10' within 7 s tore  diameters of the release point i n  a l l  cases. 
Thus a decrease i n  eject ion velocity without a corresponding increase 
i n  nose-down pitching moment may yield unsatisfactory release 
character is t ics .  
CONCLUSIONS 
A n  experimental investigation was conducted i n  a f ree  j e t  t o  deter- 
mine the eject ion release character is t ics  and f l i g h t  behavior of the MB-1 
rocket i n  the close v ic in i ty  of the fuselage of a model of the Convair 
F-106~ airplane. The t e s t s  were made a t  a Mach number of 1.59 f o r  a 
.6 simulated a l t i t ude  of 18,670 fee t .  The Reynolds number was 11.3 x 10 
per foot.  
Changes i n  missile-bay configurations by the addition of Falcon 
missiles caused a large change i n  the MB-1 release character is t ics .  
Successful ejections were made by applying a proper combination of 
NACA RM SL57E07 
eject ion velocity and nose-down pitching moment a t  release to  overcome 
the aerodynamic forces produced i n  the v ic in i ty  of the fuselage and 
missile bay. 
Langley Aeronautical Laboratory, 
National Advisory Committee of Aeronautics, 
Langley Field, Va., April 15, 1957. 
JOM B. Lee 
Aeronautical Research Engineer 
Approved : 
Chief &/~i%tless Aircraft  Research Division 
REFERENCES 
1. Faget, Maxime A. ,  and Carlson, Harry W . :  Experimental Techniques 
f o r  Predicting Store Motions During Release o r  Ejection. NACA 
F!M L55L20b, 1956. 
2. Lee, John B.,  and Carter, Howard S.: A n  Investigation of Ejection 
Releases of Submerged and Semisubmerged Dynamically Scaled Stores 
From a Simulated Bomb Bay of a Fighter-Bomber Airplane a t  Super- 
sonic Speeds. NACA RM ~56110, 1956. 
3 .  Carter, Howard S., and Lee, John B.: Investigation of the Ejection 
Release of Several Dynamically Scaled Bluff Internal  Stores a t  
Mach Numbers of 0.8, 1.39, and 1.98. NACA RM L36~28, 1956. 
4. Sandahl, Carl A., and Faget, Maxime A.: Similitude Relations f o r  
Free-Model Wind-Tunnel Studies of Store-Dropping Problems. NACA 
TN 3907, 1957 
NACA RM SL57E07 
TABU I.- MB-1 ROCKET MODEL ORDINATES 
TABLE 11.- TEST SEQUENCE AT M = 1.59 AND cy. = 2.0° 
SIMULATING 18,670 FEET 
X, i n .  
0.248 
497 
.744 
991 
1.239 
1.497 
1.927 
2.212 
2.618 
4 139 
4.701 
5 495 
r, in .  
0.166 
,248 
.312 
.362 
398 
.421 
.429 
.429 
372 
372 
359 
-279 
Test 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
Number of Falcon 
missiles,  Nf 
0 
o 
2 
4 
4 
2 
4 
o 
2 
4 
Figure 
3 
3 
4 
4 
4 
5 
5 
6 
6 
6 
20, 
f t / sec  
29.0 
28.5 
28.5 
28.5 
28.5 
27.3 
27.3 
23.0 
23.0 
23.0 
%, 
f t - lb  
-2,000 
-1,100 
-1,100 
-1,100 
-1,100 
-2,000 
-2,000 
-1,170 
-1,170 
-1,170 
At, 
sec . 
0.00202 
.o0205 
.o0205 
.00205 
.00205 
.00203 
.00205 
.00205 
.00205 
,00203 

- - -  
m e . .  
e e  &* om* > 1 
I 5.495 
* 
View rotated 45 O 
5.674 
(b) Sketch of model. All dimensions are in inches. 
Figure 1.- Concluded. 
 force & Release pin 
Cross bar \Store ejection pin Section - A , 
Nozzle top plote 
13.877 18.260 20.479 
Nozzle Exit 
(a) Side view. 
Figure 2 . -  The 0.04956-scaled model of the Convair F-106~ airplane in preflight test facility. 
All dimensions are in inches. 
Nozzle exit \ I 
(b) Top view. 
Figure 2.- Concluded. 

NACA RM SL'j7E07 
T*. t/a 
(b) Oscillations. 
eorizontal  a is taoos ,  x/d Roakst pitch angle, 0". d.6 
( c )  Trajectories. (a) Oscillations trajectories. 
Figure 3.- Concluded. 
1 
a*. 
F a  . 
a 
*a 
D 
8 . 
0000 
NACA RM SL57E07 
l 
om. 
(b) Oscillations. 
-5 0 5 10 15 -20 -10 0 10 20 
B o ~ i z o n t c d  d i s t a n c e ,  x/d Rocket p i t c h  u l g l s ,  By, dog 
(c) Trajectories. (d) Oscillations trajectories . 
Figure 4. - Concluded. 
Test 6; Nf = 2; i, = 27.3 feet per second. 
~ e s t  7; ~ l f  = 4; i, = 27,3 feet  per second. 
eopic photograp 
- B-I roclrat e3ectia w 
=. -2,000 foat 
NACA RM SL57E07 
Time., t/d 
(b) Oscillations. 
Bor1z0nt.l d i s t a n c e ,  x/d Rocket pitch mgls, %. dog 
(c) Trajectories. (d) Oscillations trajectories. 
Figure 5. - Concluded. 

NACA RM SL57E07 * "  4 " r U I  
INVESTIGATION OF EJECTION RELEASES OF AN MB-1 ROCKET 
FROM A 0.  O ~ ~ ~ ~ - S C U D  MODEL OF THE CONVAIR 
F-106~ AIRPLANE AT MACH NUMBER 1.59 
COORD. NO. AF-AM-57 
By John B . Lee 
ABSTRACT 
A n  investigation has been made of the release character is t ics  of 
the MB-1 rocket from a 0.04956-scaled model of the Convair F-106~ a i r -  
plane. Tests were conducted i n  the 27- by 27-inch p r e f l i g h t . j e t  of the 
Langley Pi lo t less  Aircraft  Research Station a t  Wallops Island, Va.,  a t  a 
Mach number of 1.59 a t  an 18,670-foot simulated a l t i tude .  The purpose of 
the investigation was to determine the eject ion veloci t ies  and pitching 
moments required to  e j e c t  the MB-1 rocket a t  near leve l  a t t i t ude  with 
the f i n  t i p s  retracted. Successful ejections were made by applying the 
proper combination of ejection velocity and nose-down pitching moment a t  
release t o  counteract the nose-up moments produced by aerodynamic forces. 
INDEX HEADrnGS 
Flow, Supersonic 
Stores - Airplane Components 
Aerodynamic Loads, Bodies 



Investigation of Ejection Releases of an MB-1 Rocket from a 0.04956-Scaled Model of the Convair F-106A Airplane at Mach Number 1.59

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IP
Copy £-+
RM SL57E07MHPEMTIAI
RESEARCH MEMORANDUM
for the
U. S. Air Force
INVESTIGATION OF EJECTION RELEASES OF AN MB-1 ROCKET
t
FROM A 0.04956-SCALED MODEL OF THE CONVAIR
F-106A AIRPLANE AT MACS NUMBER 1.59
COORD. NO. AF-AM-57
By John B. Lee
Langley Aeronautical Laboratory
Langley Field, Va.
This material
of the
NATIONAL ADVISORY COMMITTEE
FOR AERONAUTICS
WASHINGTON
..
00/0.5,.% 2 816 7
Restriction/Classification Cancelled
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NACA EM SL57E07
NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS
•. RESEARCH MEMORANDUM
*•••
*•"*« for the
••
•• ' U. S. Air Force
INVESTIGATION OF EJECTION RELEASES OF AN MB-1 ROCKET
FROM A 0.04956-SCALED MODEL OF THE CONVAIR
F-106A AIRPLANE AT MACH NUMBER 1.59
COORD. NO. AF-AM-57
By John B. Lee
SUMMARY
An investigation has been conducted in the 27- by 27-inch preflight
jet of the Langley Pilotless Aircraft Research Station at Wallops, Island,
Va., of the ejection release characteristics of the MB-1 rocket -from the
missile bay of a O.Olj-956-scaled model of the Convair F-106A airplane.
The MB-1 rocket was ejected vith its fin tips retracted, for a simulated
altitude of 18,670 feet at a Mach number of 1.59.
Successful ejections were made with the MB-1 rocket at supersonic
speeds by applying a proper combination of ejection velocity and nose-
down pitching moment to the rocket at release. The pitching moment at
release required to keep the MB-1 rocket at a near level attitude after
release was influenced by the presence and number of Falcon missiles in
the missile bay.
INTRODUCTION
At the request of the U. S. Air Force, an investigation was made to
determine the ejection characteristics of an internally carried MB-1 rocket
from the missile bay of a model of the Convair F-106A airplane. To carry
the rocket in the F-106A, the fin tips are retracted inside the fins with
the fin tips telescoping out upon the firing of the rocket. It is required
that the rocket be at near level flight upon the firing of the rocket motor
NACA RM SL57E07
t
and the extension of the fin tips. Adverse pitching moments of a store
.. due to aerodynamic forces, in the vicinity of the missile bay and fuse-
•**••• lage, may endanger the airplane. It was thus necessary to investigate
the release characteristics of the rocket and develop an ejection method*••» .
* that would give the desired rocket attitude at the instant of rocket
'*; firing. This investigation included a study of the rocket with fins
retracted only. An ejector was designed that would impart an initial
pitching moment to the rocket at release that would overcome any adverse
pitching.
In reference 1, from a comparison of static and dynamic tests, there
were strong indications that model tests should include all pertinent
details of the full-scale bomb bay. Additional investigations of dynamic
models (refs. 2 and j) also showed this to be true. The missile bay of
the F-106A is designed to carry up to four Falcon missiles with the MB-1
rocket. This investigation included these Falcon missiles with their rail
launchers. The effects of several missile bay configurations with and
without Falcon missiles were investigated.
The models were dynamically scaled by the light-model method as out-
lined in reference 4. The models simulated an altitude of 18,670 feet at
a, Mach number of 1.59 with a Reynolds number of approximately 11.3 X 10
per foot. This investigation was made with a 0.04956-scaled model in the
preflight jet of the Langley Pilotless Aircraft Research Station at
Wallops Island, Va.
SYMBOIS
d diameter, 0.859 in. for rocket missile
I rocket model length, in.
M Mach number
MQ equivalent full-scale applied moment at rocket release,
positive nose up, ft-lb
N-f number of Falcon missiles in missile bay
r radius, in.
t time, sec
At time interval of stroboscopic photographs, sec
NACA RM SL57E07
x horizontal distance of rocket model center of gravity with
>. origin at point of release, positive downstream, in.
*«..
z vertical distance of rocket model center of gravity with
origin at point of release, positive down, in.
z0 ejection velocity of rocket model at point of release, ft/sec
Of angle of attack of airplane fuselage, deg
QM rocket model pitch angle in reference to undisturbed free-
stream direction, deg
MODELS AND APPARATUS
MB-1 Rocket
A photograph and a sketch of the MB-1 rocket with retracted fin
tips are shown in figure 1, and the rocket model ordinates are shown in
table I. To store the rocket in the missile bay of the full-scale air-
plane, with Falcon missiles, the MB-1 fin tips are retracted into their
respective fins. For this investigation only models with retracted fins
were used.
The MB-1 rocket has a fineness ratio of 6A and a center-of-
gravity position of 55 percent of the rocket length from the nose. Fig-
ure l(b) shows the position of the ejection pins. The rocket was carried
in the missile bay at a negative incidence angle of 2° with the airplane.
All tests for this investigation were made at a fuselage angle of attack
of 2°.
A model weight of 0.201 pound and an inertia of O.MkL pound-square
inch simulated an altitude of 18,670 feet for a full-scale weight of
800 pounds and an inertia of 720,000 pounds-square inches.
Fuselage and Missile Bay
A sketch of the O.Ol4-956-scaled model of the Convair F-106A airplane
used for this investigation is shown in figure 2. The model was attached
to an extension of the nozzle plate by two struts, one attached to each
wing. The nose of the model extended into the nozzle, and the front end
of the MB-1 rocket was approximately 3/8 inch downstream of the nozzle
exit. The airplane model was at a 2° angle of attack in the test section.
Figure 2 shows the model set up with Of = 0°.
NACA RM SL57E07
The missile bay was constructed to carry four Falcon missiles in
addition to the MB-1 rocket. The Falcon missiles were removable from
the model missile bay as necessary for the tests. For a missile-bay
combination of two Falcon missiles, (Nf = 2) the two forward Falcon
missiles were in place with the two rear Falcon missiles removed.
Ejection Mechanism
An ejector cylinder was located directly above the model on the
nozzle-top-plate extension (fig. 2(a)). The ejector rods passed through
protective rods that connected to the top of the airplane model. An air-
pressure cylinder applied force to a crossbar (fig. 2(a)). The ejector
cylinder with the crossbar could be adjusted to apply different forces to
the ejector rods to obtain the desired pitching moment of the rocket.
The rocket was locked into the ejector rods by pins backed by tension
springs. The force of the ejector rods on the ejector pins would over-
come the force of the tension springs and the model would be ejected.
The ejection stroke length was 0.5 inch.
Preflight Jet
This investigation was made in the 27- by 27-inch preflight jet of
the Langley Pilotless Aircraft Research Station at Wallops Island, Va.
The test setup is shown in figure 2. A description of the tunnel is given
in reference k.
Photography
Stroboscopic photographs were obtained by using a spinning disk with
slits in front of the camera lens (ref. 2). The time interval between
frames was approximately 0.002 second.
RESULTS AND DISCUSSION
The purpose of this investigation was to determine the flight char-
acteristics of the MB-1 rocket in the vicinity of the airplane and to
determine the type of release necessary to maintain a near level flight
attitude. Table II gives the tests and the pertinent data of each test.
Figures 3 to 6 present the stroboscopic pictures and plots of the rocket-
model oscillations and trajectory. Distances divided by the maximum
rocket-model diameter of d = 0.859 are shown in the motion plots to
nondimensionalize the results.
NACA RM SL57E07
This investigation was made at M = 1.59> and an altitude of
18,670 feet was simulated. The airplane angle of attack was 2° and the
rocket incidence angle to the airplane was -2°. Combinations of Falcon
missiles in the missile bay included % = 0, 2, and 4; where Nf = 2,
the two front Falcon missiles were included. Ejections were made at
z0 = 23.0 to 29.0 feet per second and the pitching moment at release
MQ was equivalent to -1,100 to -2,000 foot-pounds, full scale.
Figure 3 shows the effect of changing the pitching moment at release
from -2,000 to -1,100 foot-pounds with zo = 29.0 and 28.5 feet per second,
respectively, with Nf = 0. The pitching moment of -2,000 foot-pounds at
release, test 1, was excessive and caused the MB-1 rocket to pass through
the airstream in a nose-down attitude. With a decrease in pitching moment
to -1,100 foot-pounds, test 2, the rocket pitch attitude reached a maximum
9™ of -10° at approximately 5 rocket diameters below the release point
(fig. 3(<i)). The rocket pitch attitude was 0° at 10 store diameters and
stayed within 9^ = k° thereafter. Therefore; by regulating the pitching
moment at release, the desired pitch attitude can be obtained to allow the
firing of the missile rocket.
Ejections of the MB-1 rocket at zo = 28.5 feet per second and
MQ = -1,100 foot-pounds with different missile-bay combinations of Falcon
missiles are shown in figure h. Test 2 is repeated in figures Mb), (c),
and (d) for comparison purposes. With two Falcon missiles in the missile
bay, the rocket pitch attitude remained within -12° for 10 store diameters
and then pitched to a larger negative angle (test 3)- With four Falcon
missiles in the missile bay, test 4, the MB-1 rocket pitched nose up after
release and diverged. The rocket pitch angle, however, was less than 10°
for 8 rocket diameters below the release point. Test 5, made under iden-
tical conditions, checked the results of test 4, indicating the degree of
repeatability of the test technique even for divergent conditions. The
missile-bay configuration is thus shown to have a large effect on the
rocket pitching characteristics; however, the rocket trajectories for all
tests remained approximately the same for 10 store diameters.
The greatest change in release conditions appeared between missile-
bay combinations of N-f = 2, test 3, and Nf = k, test 4, with the rocket
changing from a nose-down attitude to a divergent nose-up attitude,
respectively. The change between Nf = 0 and Nf = 2 was small and the
releases considered favorable, even for a case of a rocket misfire.
The effect of missile bay combinations with Mo = -2,000 foot-pounds
on the MB-1 trajectory is shown in figure 5. For test 1, Nf = 0, and
test 6, Nf = 2, the rocket had pitched to -30° or more by the time the
NACA EM SL57E07
missile was 10 store diameters below the release point. In test k,
however, with Nf = k, the MB-1 rocket remained within 9M = -11° for
13 rocket diameters below the release point.
It thus appears that MQ = -1,100 foot-pounds is sufficient for
missile bay configurations of Nf = 0 and Nf = 2 with high ejection
velocities. If the missile rocket fires within 8 store diameters of
the release point, MQ = -1,100 foot-pounds should also be sufficient for
N.f = 4. However, an increase of pitching moment of over 80 percent, up
to -2,000 foot-pounds, is needed to keep the rocket in an attitude that
would not endanger the airplane in case of a rocket misfire. It thus
appears that the elimination of the two rear Falcon missiles would sim-
plify the release problems; that is, a smaller range of pitching moment
and ejection velocity would be needed to obtain good releases.
The ejection velocity was decreased to 23 feet per second (fig. 6)
with M0 = -1,170 foot-pounds. For all missile-bay configurations the
rocket pitched to a high positive angle. The rocket remained below
Gj^ = 10° within 7 store diameters of the release point in all cases.
Thus a decrease in ejection velocity without a corresponding increase
in nose-down pitching moment may yield unsatisfactory release
characteristics.
CONCLUSIONS
An experimental investigation was conducted in a free jet to deter-
mine the ejection release characteristics and flight behavior of the MB-1
rocket in the close vicinity of the fuselage of a model of the Convair
F-106A airplane. The tests were made at a Mach number of 1.59 for a
simulated altitude of 18,670 feet. The Reynolds number was 11.3 x 10
per foot.
Changes in missile-bay configurations by the addition of Falcon
missiles caused a large change in the MB-1 release characteristics.
Successful ejections were made by applying a proper combination of
NACA KM SL57E07
ejection velocity and nose-down pitching moment at release to overcome
the aerodynamic forces produced in the vicinity of the fuselage and
missile bay.
Langley Aeronautical Laboratory,
National Advisory Committee of Aeronautics,
Langley Field, Va., April 15, 1957-
&x£?7&o/^i
Js John B. Lee
Aeronautical Research Engineer
Approved:
to. MM.
/Joseph A. Shortal
Chief $f/Pilfctless Aircraft Research Division
sam
REFERENCES
1. Faget, Maxime A., and Carlson, Harry W.: Experimental Techniques
for Predicting Store Motions During Release or Ejection. NACA
RM L55L20b, 1956.
•2. Lee, John B., and Carter, Howard S.: An Investigation of Ejection
Releases of Submerged and Semisubmerged Dynamically Scaled Stores
From a Simulated Bomb Bay of a Fighter-Bomber Airplane at Super-
sonic Speeds. NACA RM L56I10, 1956.
3- Carter, Howard S., and Lee, John B.: Investigation of the Ejection
Release of Several Dynamically Scaled Bluff Internal Stores at
Mach Numbers of 0.8, 1.39, and 1.98. NACA RM L56H28, 1956.
h. Sandahl, Carl A., and Faget, Maxime A.: Similitude Relations for
Free-Model Wind-Tunnel Studies of Store-Dropping Problems. NACA
TN 3907, 1957-
NACA KM SL57E07 8
TABLE I.- MB-1 ROCKET MODEL ORDINATES
x, in.
0.248
.497
.744
.991
1.239
1.497
1-927
2.2122.618
4.1594.701
5.495
r, in.
0.166
.248
• 312
.362
.398
.421
.429
.429
.372
• 372
.359
.279
TABLE II.- TEST SEQUENCE AT M = 1.59 AND
SIMULATING 18,670 FEET
= 2.0°
Test
1
2
3
4
5
6
7
8
9
10
Figure
3
3
4
4
4
5
5
6
6
6
Number of Falcon
missiles, Nf
0
0
2
4
4
2
4
0
2
4
*0>
ft/sec
29-0
28.5
28.5
28 = 5
28.5
27-3
27-3
23.0
23.0
23-0
MO,
ft-lb
-2,000
-1,100
-1,100
-1,100
-1,100
-2,000
-2,000
-1,170
-1,170
-1,170
At,
sec.
0.00202
.00205
.00205
=00205
.00205
.00203
.00205
.00205
.00205
.00203
(a) Photograph .of 'model. .L-96601.1
Figure 1.- A 0.0^ 956-scaled model of the MB-I rocket.
1
>
COf
5.674
View rotated 45
(t>) Sketch of model. All dimensions are in inches.
Figure 1.- '"'oncluded.
Ejection rod
Spring
Releose pin
Store ejection pin
Extension of nozzle top plote
tored position (-1419 R.L.)
Nozzle <t
-2.225 0
13.877 18.260 20.479
Nozzle Exit
35.258
COf
VJ1
(a) Side view.
Figure 2.- The O.OU956-scaled model of the Convair F-106A airplane in preflight test facility.
All dimensions are in inches.
•• • t
Nozzle
o
>
O
-J
(b) Top view.
Figure 2.- Concluded.
NACA KM SL57E07
Test 1; M0 = -2,000 foot-pounds; zo = 29.0 feet per second.
Test 2; Mo = -1,100 foot-pounds; ZQ = 28.5 feet per second.
(a) Strdboscopic photographs. L-5 i
Figure 3•- MB-I rocket ejections with changes in initial pitching moment
for Nf = 0.
NACA RM SL57E07
5 -ID
J-
.'
-Uo
-50
-to
-.005
—
>
^ , : I
.005 .010 .015 .020 .025 .050 .035 .odo
Tine, t/d
(t>) Oscillations.
vj-tr
.............
rf
.
:_
r — L-. rr —
,0 -1(0
-T ~T HgJ-
uJ^r
e^ i[
Te«\ »0
» O 1 -2000
a 2 -iioo
! . . .^^^ -,_T ,.»». ».--»-.
*t -— • • • • " —
-30 -20 -10
! ; : ! i i = ; i i ; i i ! :
T . 5
2
'-° ;j|;;i
28.5
0 11
(c) Trajectories. (d) Oscillations trajectories.
Figure 3-- Concluded.
NACA RM SL57E07 15
Test 5; Nf = 2.
Test b; Nf =
Test 5; Nf = 1+; repeatability of test 4,
(a) Stroboscopic photographs. L-57-1585
Figure U.- MB-I rocket ejections with changes in missile bay.
M0 = -1,100 foot-pounds; ZQ = 28.5 feet per second.
NACA RM SL57E07 16
hi:: : : : i: :;::;: : : : : : : :MtliiillM!
ko I::-::::-:: 4J— — *-*-|^-r
:::::: ::::::::::::::::::::: ::: if :::::::
-
30 :4±-_-- : - : t + T :;
M
•fl
-
 20 |:|!;jii;;!E!!;!;i;;i!!!i;;!;;i;;;!;!;i;^ . .
W -t ^
S < \ \ jAj
S 10 ii|ia g;;;;|ffi;|;;;:|;;:;!;p|!|
a
 ° ^i^P^ ^  i^ i ^  p ^ : i ^
-10 t — f i i i j ; : : ; ; : : :|:::!jiiiiiii —
• - - j - - ^ 1 - - - - - + —
.», ill!!
r r 4t^ tfe!Jlllilliiil I I l-U-lil l i t
lr;1'
- - 1 ; ; : : : ! ; : :
, /^ TMt »f
- ;| j ; : i ; | | ; 2 0
: - ::: O 5 2
— A 1, k
T«Bt U 7
::::::::!;;:::;:i:5:il;:::::::::::::::::::::::::
':':':': 1
__ ^ 4. 4;
::: :: -i
,
.:s ::::::::::::::::::::::::::::::
'.005 .005 .010 .015 .020 .025 .030 .035 .oltO .ol»5
Tims, t/d
(t>) Oscillations.
(c) Trajectories. (d) Oscillations trajectories.
Figure k.- Concluded.
NACA RM SL57E07 17
Test 6; Nf = 2; zo = 27.5 feet per second.
Test 7; Nf = h; ZQ = 27.5 feet per second.
(a) Stroboscopic photographs. L-57-1586
Figure 5.- MB-I rocket ejection with changes in missile "bay.
MQ = -2,000 foot-pounds.
NACA KM SL57E07 18
-Uo
-50
-to.
_
rtrr
ffi
<
r
T«.t «f «0
1 0 29.0
k 6 2 27.3
o 7 U 27.3
—
.005 .oxo .015 .020 .025 .030 .035 .ol*o
Tlie, t/d
(b) Oscillations.
15
20
?•'•
iii
-5 o 5 10
Horizontal dlatancef z/d
-50 -Uo -JO -20 -10
Rocket pitch angle, 9_f deg
(c) Trajectories. (d) Oscillations trajectories,
Figure 5.- Concluded.
NACA RM SL57E07 19
Test 8; Nf = 0.
Test 9; Nf = 2.
Test 10; Nf =
(a) Stroboscopic photographs. L-57-1587
Figure 6.- MB-I rocket ejections with changes in missile "bay.
z0 = 23.0 feet per second; MQ = -1,170 foot-pounds.
NACA RM SL57E07 20
-.005 o
.015 .020 .025
Time, t/d
(b) Oscillations.
.050 .055 .oto .ol>5
-15-
« i:
- 5 0 5 1 0 1 5
Horizontal dlstnace, x/d
10 20 30
(c) Trajectories. (d) Oscillations trajectories,
Figure 6.- Concluded.
NACA RM SL57E07
INVESTIGATION OF EJECTION RELEASES OF AN MB-1 ROCKET
FROM A 0.04956-SCALED MODEL OF THE CONVAIR
F-106A AIRPLANE AT MACH NUMBER 1.59
COORD. NO. AF-AM-57
By John B. Lee
ABSTRACT
An investigation has been made of the release characteristics of
the MB-1 rocket from a 0.04956-scaled model of the Convair F-106A air-
plane. Tests were conducted in the 27- by 27-inch preflight jet of the
Langley Pilotless Aircraft Research Station at Wallops Island, Va., at a
Mach number of 1.59 at an 18,670-foot simulated altitude. The purpose of
the investigation was to determine the ejection velocities and pitching
moments required to eject the MB-1 rocket at near level attitude with
the fin tips retracted. Successful ejections were made by applying the
proper combination of ejection velocity and nose-down pitching moment at
release to counteract the nose-up moments produced by aerodynamic forces.
INDEX HEADINGS
Flow, Supersonic 1.1.2.3
Stores - Airplane Components 1.7.1.1.5
Aerodynamic Loads, Bodies 4.1.1.3-



Investigation of Ejection Releases of an MB-1 Rocket from a 0.04956-Scaled Model of the Convair F-106A Airplane at Mach Number 1.59

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