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The following
AeroDRAG & Flight Simulation
validation analysis uses widely available V-2 rocket
physical characteristics and flight performance information
to compare range, apogee of trajectory, velocity at burnout,
velocity at impact, burnout altitude, acceleration at burn
out and acceleration at liftoff to actual V-2 rocket flight
performance information.
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INPUT DATA: Table-1 to Table-4 display the required
V-2 airframe dimensions, fin dimensions and flight input
data required for flight analysis. Please refer to Figure-3
for a screen shot of the drag analysis screen and a
summation of the input dimensional data and Figure-4 for a
screen shot of the flight results. Finally, please refer to
Figure-8 and Figure-9 for screen shots of altitude verses
time, Mach number verses time and acceleration (G) verses
time plots. Please note: This analysis is an approximation
based on the best information available for the A-4/V-2
rocket.
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Table 1: Airframe Dimensions
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Data Input |
Airframe |
Source |
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Body Diameter [in] |
65.0 |
A-4/V-2 Resource Site |
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Ogive Nose Length [in] |
208.5 |
A-4/V-2 Resource Site |
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Body Tube Length [in] |
327.9 |
A-4/V-2 Resource Site |
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Finish Quality |
Good |
A-4/V-2 Resource Site |
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Base Shape |
Boat Tail |
A-4/V-2 Resource Site |
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Boat Tail Diameter [in] |
40.9 |
A-4/V-2 Resource Site |
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Launch Lug |
None |
N/A |
Table 2: Fin Dimensions
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Data Input |
Fin-Set 1 |
Source |
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Number of Fins |
1 |
A-4/V-2 Resource Site |
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Fin Edge Shape |
Streamlined |
A-4/V-2 Resource Site |
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Fin Thickness [in] |
4.9 |
A-4/V-2 Resource Site |
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Root Chord [in] |
158.7 |
A-4/V-2 Resource Site |
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Fin Span [in] |
41.1 |
A-4/V-2 Resource Site |
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Fin Profile |
Tapered |
A-4/V-2 Resource Site |
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Tip Length [in] |
102.6 |
A-4/V-2 Resource Site |
Table 3: Flight Input Data
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Data Input |
Stage-1 |
Source |
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Motor burn time [sec] |
65.0 |
A-4/V-2 Resource Site |
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Propellant weight [lb] |
18982 |
A-4/V-2 Resource Site |
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Number of motors |
1 |
A-4/V-2 Resource Site |
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Total loaded weight w/motors [lb] |
28219 |
A-4/V-2 Resource Site |
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Reference diameter [in] |
65.0 |
A-4/V-2 Resource Site |
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Coast time [sec] |
262 |
N/A |
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Time increment [sec] |
.042869 |
N/A |
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Nozzle expansion ratio (Ae/At) |
18.2:1 |
A-4/V-2 Resource Site |
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Initial (Sea Level) thrust (lb) |
55,100 |
A-4/V-2 Resource Site |
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Final (Vacuum) thrust (lb) |
70,107 |
Encyclopedia
Astronautica
Wikipedia
Encyclopedia |
Table 4: Launch Conditions & 2-D Flight
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Data Input |
Stage-1 |
Source |
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Temperature at launch location [deg F] |
80.0 |
N/A |
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Elevation of launch location [ft] |
0.0 |
N/A |
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Flight path angle at insertion [deg] |
49.0 |
A-4/V-2 Resource Site |
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Time from lift-off to roll initiation [sec] |
5.0 |
A-4/V-2 Resource Site |
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Time from lift-off to Flight path angle insertion [sec] |
54.0 |
A-4/V-2 Resource Site |
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Lift to drag ratio [1] |
0.0 |
N/A |
Table-5, AeroDRAG Flight Results Compared to V-2 Flight Data
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Flight Data |
AeroDRAG |
V-2 Flight Data |
% Difference |
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Range (miles) |
189.5 |
199 |
-4.8% |
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Apogee of trajectory (miles) |
59.8 |
56.0 |
+6.8% |
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Velocity at burnout (ft/sec) |
5,290.6 |
5,249.3 |
+0.8% |
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Velocity at impact (ft/sec) |
2,927.8 |
3,608.9 |
-18.9% |
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Burnout altitude (miles) |
18.3 |
17.4 |
+5.2% |
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Maximum Acceleration at burnout (G's) |
6.6 |
7.0 (a)(b)(c) |
-5.7% |
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Acceleration at lift-off (G's) |
0.95 |
0.90 |
+5.6% |
| Apogee, 90 degree lift-off
(miles) |
120.0 (d) |
114.0 |
+5.3% |
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a) G modified using: G = F/W - 1,
That is, V-2 published values have been reduce by 1G.
b) When coasting vertically in space in a gravitational field, G
= -1 when F ~ 0 and W = SS1 final weight.
c) Acceleration due to gravity of a particle in space is G =
- g0 * R^2 / r^2, where r is the distance from the center of
the earth to the particle, R is the radius of the Earth and g0
is the acceleration due to gravity at the surface of the Earth.
d) This AeroDRAG apogee result is compared to the approximate maximum
altitude achieved by the V-2 rocket for vertical
flight when used as a sounding rocket. This result is achieved by performing a one-dimensional
flight analysis with the flight path angle set to 90 degrees
from the horizontal. Burn time was increased to 70 seconds
corresponding to the maximum burn time of the V-2 rocket
motor. |
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PROPELLANT WEIGHT: The V-2 rocket used 3,710 kg of Ethyl Alcohol
(75%) and 4,900 kg of Liquid-oxygen for a total of 8,610 kg
or 18,982 lb of propellant consumed during the 65 second
burn of the rocket motor for this example.
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THRUST-TIME PROFILE:
The V-2 rocket motor developed 25,000 kg (55,100 lb) of
thrust at sea level where the atmospheric pressure is
approximately 14.7 psia. Also, when the ambient pressure is
reduced to the near vacuum of space a V-2
rocket motor developed 31,800 kg (70,107 lb)
of thrust because the low pressure of high altitude flight
allows the nozzle to
expand more efficiently from the nozzle exit to low
ambient pressure. The thrust curve is constructed using
these design conditions to define the thrust-time
plot in the Thrust-Curve Generation screen. The
thrust-time curve (saved
as an FVT file) is used in this analysis to
approximate the thrust profile of the V-2 rocket. Please see Figure-1 (below) for the input screen used to
generate the thrust-time curve for this example.
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FLIGHT
RESULTS (AeroDRAG 7.0):
Comparison between AeroDRAG & Flight Simulation
results and actual V-2 flight data compare well for range,
apogee, velocity at burn out, impact velocity, burn out
altitude, acceleration at lift-off and finally the maximum
altitude achieved by the V-2 rocket for vertical flight.
Please refer to Table-5 where these results are compared.
For example, the range predicted by the simulation for the
V-2 rocket was 189.5 miles compared to 199 miles for the
published V-2 range data for a difference of 4.8 percent.
These results include the effects of Cd verses Mach number, air density verses altitude,
propellant weight as a function of time and Cd verses rocket shape and
Mach number. However, wind velocity, Earth curvature and other perturbations are not included
in the 2-D analysis at present. Please note, the effects of Earth
curvature may be neglected for ranges less than 500 km
(310.7 miles). Finally, please refer to Figure-2, Figure-3,
Figure-4 and Figure-5 for more information concerning the
procedure required to generate program output.
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Figure-1, Thrust-Time Profile - Manual Input screen and Free-Form
Input screen
AeroDRAG & Flight Simulation Input Data and Results Screen Shots

Figure-2, Drag Screen and Summation of
Input Data

Figure-3, Flight Screen and Results

Figure-4, Launch Point Specification
Screen

Figure-5, Altitude and Axial
Acceleration Plot Screen
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