I neglected to mention that RASAero II Version 1.0.1.0 can be downloaded
from the RASAero web site at _www.rasaero.com_ (http://www.rasaero.com) . A
link to the Version 1.0.1.0 download is on the home page.
Chuck Rogers
_CRogers168@aol.com_ (mailto:CRogers168@xxxxxxx)
In a message dated 4/5/2017 3:22:44 P.M. Pacific Daylight Time,
dmarc-noreply@xxxxxxxxxxxxx writes:
Back on ARocket again after a hiatus due to IT/e-mail issues.
Just a reminder that a while ago a new version of the RASAero II software
was released which, of interest to this group, included a modification to
the power-on base drag models for very large nozzle exit diameters at
supersonic and hypersonic Mach numbers, for more accurate power-on drag
coefficient (CD) predictions for the first and second stages of launch
vehicles. If
you're using RASAero II for launch vehicle aero data, be sure to download
and use RASAero II Version 1.0.1.0.
A couple of tips for using RASAero II for launch vehicle aero data:
1) Be sure to enter the nose tip radius on the nose cone input screen.
For many launch vehicles there is typically a large nose tip radius. Enter
in the nose cone basic shape (tangent ogive, power law, elliptical), and
then add the large nose tip radius.
2) For trajectory runs RASAero II continuously varies the aero data with
altitude. When generating aero data for input into other programs using the
Aero Plots (Pages 46-59 in the Users Manual), or the Run Test aero tabular
output (Pages 68-74 in the Users Manual), the default is the aero data will
be generated with the altitude held constant at sea level.
For entering a schedule for the altitude with Mach number along the ascent
trajectory, the Mach-Alt input feature (Pages 66-68 in the Users Manual)
can be used.
Typical Mach-Alt values to be used for a launch vehicle are:
Mach Alt (ft)
0.0 0.0
5.0 100,000
25.0 100,000
I recommend just holding the altitude at 100,000 ft, once 100,000 ft is
reached in the Mach-Alt inputs.
Again, there's no need to enter anything in the Mach-Alt inputs when
running a trajectory in RASAero II, the altitude with Mach number for
generating
the aero data is done automatically along the trajectory. The Mach-Alt
input is only used for the Aero Plots and the Run Test aero tabular output.
If you make no input, then the default of sea level will be used.
But if you're typing aero data from the Aero Plots or the Run Test tabular
output for a launch vehicle into another program, then the Mach-Alt input
feature should be used.
Chuck Rogers
