Development of the HTV3X
Hypersonic Test
Vehicle
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HTV3X Hypersonic
Aircraft Wind Tunnel Model
HTV3X Hypersonic
Aircraft
AeroWindTunnel™
Wireframe Design
HTV3X Subsonic Wind Tunnel Model Orthographic Design 
The Hypersonic Test Vehicle project is AeroRocket's version of the DARPA HTV3X
also known as
the Blackswift which represents AeroRocket's proposal for a
hypersonic aircraft capable of flight to 300,000
feet and top speed from Mach 5 to Mach 10. A
miniature subsonic wind tunnel model of the HTV3X has been
fabricated for experimental determination of drag
coefficient (CD) using AeroRocket's 1 inch diameter supersonic
blowdown
wind tunnel. In addition, an
AeroWindTunnel
analysis has been performed that validates results from subsonic and
supersonic wind tunnel tests. Please see the
Wikipedia article about the HTV3X that contains DARPA video
and other interesting information about this proposed (now cancelled) space plane. 
RESOURCES AVAILABLE FOR THE DEVELOPMENT OF
THE HTV3X
SUPERSONIC/HYPERSONIC FLIGHT VEHICLE CONCEPT

SUBSONIC WIND TUNNEL
The
AeroRocket subsonic wind tunnel
is a suction system powered by a two speed 1/3 horsepower fan.
The test section is 7 inches wide x 10 inches high x 16 inches long. A research quality pitot
tube measures the difference between static and dynamic
pressure in the test section. The
resulting differential determines flow velocity using an analog velocity
meter. Small models that represent large designs are
routinely tested in the AeroRocket wind tunnel. 
SUPERSONIC BLOWDOWN WIND TUNNEL (1" DIAMETER)
The new AeroRocket 1" diameter supersonic blowdown wind tunnel performs
drag measurements up to Mach 3.
AeroRocket's expertise in the fabrication
of miniature wind tunnel models makes possible the measurement
of supersonic Cd for designs ranging from
simple high power rockets to the complex HTV3X. This
new supersonic wind tunnel has already been used to determine drag
coefficient of the HTV3X. These measurements determined drag coefficient for the HTV3X to
be: Cd = 0.2435 at M = 1.6. 
Miniature HTV3X Supersonic BlowDown Wind Tunnel Model 
Closeup view of the new 1"
diameter Supersonic BlowDown Wind Tunnel 
HTV3X BLOWDOWN
WIND TUNNEL RESULTS 
Cd, BlowDown Wind
Tunnel
Max. Frontal Reference Area 
Cd, Ideal
Wave Drag
Equation
Max. Frontal Reference Area 
Cd_{wave} = 0.2435 @ M =
1.6 
Cd_{wave}
= 0.2992 @ M =
1.6 
HTV3X MODEL (1" TUNNEL)
Length = 12.7 mm
Width = 6.35 mm
Thickness = 2.388 mm
S_{max} = 15.161 mm^{2}
P_{static} = 0.106 atm
P_{0} = 2.241 atm
Blockage Factor = 2.992%
q = 1/2
g
P_{static } Mn^{2 }= 0.518 atm 
FULL SIZE HTV3X
Lb = 15.62 m
S_{max} = 7.153 m^{2
}S_{wing} = 52.628 m^{2}
E_{wd} = 1.5
L_{LE} = 54.44 deg
A_{inlet} = 2.0 m^{2} 

Testing The miniature HTV3X in the new 1" BlowDown Wind
Tunnel at M = 1.6. 

The zerolift
drag coefficient (Cd) verses
Mach number curve displayed below
(blue line) was generated using
AeroWindTunnel
with SurfaceRoughness equal to None. For this
analysis the inlet area, A_{inlet }
is included. The classically generated Cd verses Mach number curve
(red dots) was generated
using the hypersonic wave drag equation (CD_{wave})
added to base drag (Cd_{base}) then
plotted verses
the
AeroWindTunnel
results.

AERODYNAMICS ANALYSIS
The
Computational Fluid Dynamics (CFD) pressurecontour plot
displayed to the right is the result of two separate
twodimensional
AeroCFD analyses. The upper half of the twodimensional analysis represents the upperhalf of the HTV3X airframe
and the lower twodimensional analysis in the plot
represents the lowerhalf of the airframe to form the entire
Mach 2.64 HTV3X flow pattern.
Cd 
2D AeroCFD RESULTS 
0.418 
A_{inlet} excluded. Cd_{base}
and Cd_{friction} included. 
0.301 
A_{inlet}, Cd_{base}
and Cd_{friction} included. See plot below. 
AeroWindTunnel Cd
verses M
(blue line) compared to the Cd
at M = 2.64
predicted by AeroCFD
(red dot) where A_{inlet
}
Cd_{base} and Cd_{friction} are included. 

AeroWindTunnel Fuselage Geometry
and WingFuselage Aerodynamics specifications of the HTV3X
vehicle. 
STATIC TESTING
Prior to flight testing an actual HTV3X an existing flight
vehicle, the X30 NASP representing similar aerodynamics
will be tested. The
image on the left depicts the X30 NASP mounted on its dualrail launcher.
AeroWindTunnel determined that for static and dynamic stability a forwardmounted rocket motor is
required. The
image on the right
illustrates a static test firing intended to determine extent of
damage to the airframe and ducting of the X30.
No exhaust damage was observed to the ducting indicating
additional thermal protection is not necessary.
The X30 is now ready for rocket powered glider flight testing.
Update: The first flight test of the X30 NASP was
successful. Rocket was recovered with only slight damage. 
Static test firing of the X30 NASP
QuickTime Movie (700KB)
Requires QuickTime from
Apple Computer 
FLIGHT
TESTING
The X30
NASP model rocket was successfully launched on Friday,
March 10, 2017 at 10:56 am. Video recorded the launch as the
X30 lifted off its rails at an initial flight angle of 45
degrees. During powered flight the AOA maintained
approximately 45 degrees until burnout after which the
vehicle entered the coast phase of flight. The X30's
lift to drag ratio (L/D) of 3 allowed the vehicle
to perform a rather steep glide to land undamaged
approximately 112 feet from its launch point. Table1
presents results of the successful flight and are compared
to results from the AeroDRAG
flight analysis computer program. AeroDRAG has been used
successfully to predict flight trajectory of professional
rockets like the Atlas missile and model rockets with equal
success. Please see Figure1, Figure2 and Figure3 (below)
that depict the X30 shortly after rocket motor ignition,
during ascent and finally during the glide phase of
flight. Finally, please
see a screen shot of the AeroDRAG analysis results that are also
displayed in Table1. These results will form the basis for
the analytical and fabrication capability to launch the
HTV3X. 
TABLE1, X30 NASP Flight
Information
Flight Data 
AeroDRAG Results 
Measured Flight
Data 
Maximum
Range 
122.3 ft /
37.28 m 
112 ft / 34.138 m 
Burnout
Altitude 
8.75 ft
/ 2.67 m 
 
Burnout
Velocity 
54.88
ft/sec / 16.73 m/sec 
 
Maximum
Altitude 
28.81 ft /
8.78 m 
29.0 ft /
8.84 m 
Time to
Impact 
4.05
seconds 
4.1 seconds 
Three sequences during the
successful flight of the AeroRocket X30 NASP model rocket.
Figure1 depicts the X30 shortly after ignition.
Figure2
depicts the X30 at burnout and insertion into the coast
phase of flight. Figure3 depicts the X30 glide phase of
flight.
X30 NASP model rocket flight
analysis using the
AeroDRAG
flight analysis computer program. Red line indicates powered
flight and blue line indicates coast phase of flight. 
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