SRM.xls is an MS EXCEL spreadsheet that takes user-inputted motor and grain geometry data and computes Kn over the duration of the motor burn, generates a pressure-time curve, a thrust-time curve, as well as performance parameters such as total impulse and delivered specific impulse. Motor performance data is also summarized for easy input into a trajectory simulation software, such as SOAR. Although primarily intended for designing motors using KN-Dextrose or KN-Sorbitol propellant, other propellants may be specified with user inputted propellant properties.
Solely for cylindrical grain configurations, such as BATES.
Written by R.A. Nakka. SRM_2014.xls is a newly released version. Although similar to the original SRM.xls, this revised version simplifies the design process by allowing the user to specify chamber pressure (rather than Kn) as a design parameter. The propellant choice has been expanded to include additional sugar propellant variations. A nozzle design worksheet has been added to help the user to visualize the nozzle geometry. Drop-down menus have been added to ease selection of parameters.
SRM_2014_RU.ZIP 1.604 Mbytes Zipped EXCEL 2000 spreadsheet Russian language version of SRM_2014, translated by Vadim Zaharchenko. Freeware
SRM_2014_BG.RAR 485 kbytes Zipped EXCEL 2000 spreadsheet Bulgarian language version of SRM_2014, translated by George Andonov. Freeware
SRM 1.2.ZIP Version: 1.2 536 kbytes Zipped EXCEL 2000 spreadsheet Freeware
A free-to-use on-line application, METEOR is a convenient, validated tool for designing rocket motors. Includes some useful additional features not currently implemented in SRM.XLS
METEOR: DESIGN YOUR SOLID ROCKET MOTOR
Written by Jordan Content and Jérôme Bise of Lyon, France.
This is an MS EXCEL spreadsheet that is used to determine the Design Pressure and Burst Pressure of a solid rocket motor casing. Also determines the elastic deformation of the casing under pressure (important for case-bonding consideration). Strength and mechanical properties are supplied for many casing materials such as steels, aluminum alloys, PVC, etc.
Written by Richard Nakka.
CASING.XLS Version 1.03 61kbytes EXCEL 5.0 spreadsheet Freeware
CASING_BG.XLS 70kbytes EXCEL spreadsheet Bulgarian language version of CASING translated by George Andonov. Freeware
This is an MS EXCEL spreadsheet that may be used to estimate the chamber pressure that occurs in a rocket motor due to combustion of a pyrotechnic igniter. Use of a properly sized pyro igniter is important for efficient rocket motor design. The motor should reach full operating pressure rapidly without wasting propellant (and thereby reducing Isp). As well, it is important to avoid overpressurization. Although tailored for black powder igniters, this spreadsheet may be used for other pyrotechnic mixtures, as well. The latest version of this spreadsheet (v1.1) also computes parachute ejection charge force.
Written by Richard Nakka. IGNITER.XLS Version 1.1 74kbytes EXCEL 2000 spreadsheet Freeware
IGNITER_BG.XLS 47kbytes EXCEL spreadsheet Bulgarian language version of IGNITER translated by George Andonov. Freeware
Windows software that converts units for Force, Pressure, Density, Area, Distance, Volume and several other measures. Very convenient and simple to use, highly recommended. Written by Joshua F. Madison. www.joshmadison.com/soft , or download it here:
CONVERT.ZIP Version 4.08 168 kbytes Zipped file Freeware
This Excel spreadsheet is meant to serve as a design aid for amateur/experimental/model rockets. A simple, easy to use spreadsheet that determines the total impulse of a motor that is required to achieve an altitude goal. Metric units. Written by Richard Nakka.
EzImpulse_v1.01.xlsm Version 1.01 40kbytes Excel macro-enabled spreadsheet Freeware
Screen-capture of EzImpulse showing INPUT DATA and RESULTS
This Excel spreadsheet is intended as an easy-to-use design aid for hobby rocketry. Unlike most rocket simulation programs, which predict peak altitude for a given rocket and motor combination, this progam instead considers peak altitude as a design goal. Based on this goal, the program computes what size motor is required to reach this peak altitude. Both English and Metric units. Written by Richard Nakka.
EzRocket.xls Version Beta 92kbytes EXCEL 97 spreadsheet Freeware
EzRocket_BG.RAR 24 kbytes Zipped EXCEL 2000 spreadsheet Bulgarian language version of EzRocket, translated by George Andonov. Freeware
An easy to use Excel spreadsheet that predicts the peak altitude, maximum velocity, burnout altitude, acceleration and time to peak altitude of an amateur rocket. Intended primarily as a rocket design aid due to its simplicity of use and ease with which variables (such as rocket mass, motor output, drag coefficient, etc.) can be modified, and the effects of such studied. Both English and Metric units. Written by Richard Nakka.
EzAlt_1.3.xls Version 1.2 195kbytes EXCEL 97 spreadsheet Freeware
EzAlt_BG.RAR 24 kbytes Zipped EXCEL 2000 spreadsheet Bulgarian language version of EzAlt, translated by George Andonov. Freeware
EzAlt_RU.XLS 92 kbytes EXCEL 2000 spreadsheet Russian language version of EzAlt, translated by Vadim Zaharchenko. Freeware
This program predicts the flight performance of a rocket. It calculates parameters such as altitude, velocity, acceleration, drag force, dynamic pressure, Mach number, and is capable of handling single-stage, multi-stage and clustered rockets. Meant to be accurate, the program utilizes efficient professional subroutines for numerical differentiation and integration. Also meant to be versatile and user friendly, it can handle supersonic rockets with a flight ceiling to 100,000 feet. as easily as low altitude model rockets with commercial engines. Runs under DOS only. Written by Richard Nakka & B.W. Nakka.
SOAR.ZIP 187 k DOS Freeware
Data files of Model Rocket Engines, for use with SOAR program. MROCKENG.ZIP 15 k
Data files of the Kappa-DX & Kappa-SB Rocket Motor, for use with SOAR program. KAPPA.ZIP 2 k
Data files of the B-200 & C-400 Rocket Motors, for use with SOAR program. ENGINE1.ZIP 1 k
This program may be of interest to the slightly less adventurous amateur rocketeer -- it predicts the performance of a "soda bottle" rocket (aka "water rocket"). A water bottle rocket, by the way, is a rocket made from a plastic soda bottle (eg 2 litre) filled with a mixture of water and compressed air (surprising performance!).
Program calculates parameters such as thrust, jet velocity, and pressure, all as a function of time, as well as total impulse and specific impulse. May be used together with SOAR to predicts the flight performance.
Source code (FORTRAN) is available upon request.
WHOOSH.ZIP 37k MSWORD 6.0 documentation DOS Freeware
& Coefficient of Drag and Centre of Pressure Estimation
This program predicts the altitude a rocket may fly given the performance parameters of the motor and the physical characteristics of the rocket. The program also determines the optimum weight of a rocket to achieve maximum altitude. Additionally, the program can estimate the coefficient of drag (Cd) and the centre of pressure (Cp) of a rocket, based on the rocket's geometry. Includes performance parameters for the PVC "G", "H", & "I" rocket motors.
Runs under DOS only. Written by: Charles D. Knight.
ROCCAD.ZIP 169 k DOS Freeware
Aerolab is a very useful and easy to use package that estimates Drag, Lift and Center of Pressure for rockets flying at velocities up to Mach 8. It also estimates the rockets Center of Gravity and Moments of Inertia and performs stability analysis within the entire velocity range.
Runs under 32 bit Windows. Written by Hans Olaf Toft.
AeroLab_2015.zip MS Windows For free distribution 1000 kb
This Excel spreadsheet allows the user to quickly and easily compute a rocket's Center of Pressure (C.P.) using the well-known Barrowman method.
Written by Richard Nakka.
BARROWMAN.XLS Version 1.03 56kbytes EXCEL spreadsheet Freeware
Altimeter Correction to Account for Launch Site Temperature
Commerical rocket altimeters use a Standard Atmosphere algorithm to calculate the peak altitude a rocket achieves in flight. The drawback to this method of calculating altitude is the Standard Atmosphere assumption that the ground level temperature at the launch site is 15O Celsius (59O F.). If the actual launch site temperature is significantly higher or lower, the reported peak altitude can be in error by an appreciable amount. This Excel spreadsheet makes a correction to account for the launch site temperature to provide a truer peak altitude.
For more information, visit Altimeter Correction to Account for Launch Site Temperature .
Written by Richard Nakka.Barometric_altitude_correction.xlsx (U.S.units)
Barometric_altitude_correction_m.xlsx (Metric units)
Version 1.0 150kbytes EXCEL spreadsheet Freeware
OpenRocket is a free, fully featured model rocket simulator that allows you to design and simulate your rockets before actually building and flying them. The main features include:
•Six-degree-of-freedom flight simulation
•Automatic design optimization
•Realtime simulated altitude, velocity and acceleration display
•Staging and clustering support
OpenRocket is an Open Source project licensed under the GNU GPL. This means that the software is free to use for whatever purposes, and the source code is also available for studying and extending. Originally written by Sampo Niskanen.
RASAero is a combined aerodynamic analysis and flight simulation software package for model rockets, high power rockets, amateur rockets and sounding rockets. I found RASAero to be refreshingly easy to learn how to use. Menus are intuitive and the software provides a nice visual representation of the rocket being designed and good graphics showing the results of flight simulation. Simulation takes into account parameters such as launch angle, wind and parachute deployment, and as such provides results for both vertical and horizontal distance flown by a rocket. Other simulation results include mach number, angle of attack, Cd and Cl, drag force, CG and CP locations, stability margin, flight path angle and rocket attitude, over the full duration of the simulated flight. Results of simulation can be exported to Excel, which is a particularly useful feature.
RASAero software is free.
Written by Charles E. Rogers and David Cooper.
This program provides a user friendly interface to run the PROPEP propellant evaluation program. PROPEP is a program that determines the chemical equilibrium composition for the combustion of a solid or liquid rocket propellant. Additionally, it determines rocket performance parameters such as Isp and C*, and nozzle design parameters. GUIPEPis a must-have program for the rocketry propellant experimentalist.
Runs under Windows. Written by Arthur J. Lekstutis, GUIPEP is available for download at Arthur's web site, which also has a link to PROPEP.
GUIPEP and PROPEP MS Windows For free distribution
ProPep 3 by Dave Cooper, 2012 MS Windows 7/10 For free distribution
Expanded data file (pepcoded.daf) for the PROPEP program. Includes entries for Dextrose, Sorbitol, Mannitol, Xylitol, Charcoals, Asphalt, Paraffin and others.
Solid Rocket Motor Theory -- GUIPEP
A thermal analysis package that determines the temperature distribution through the thickness of a motor casing wall that results from convective heating due to propellant combustion and resulting gas flow. The package consists of DOS executable file which outputs a table of results which may be copied into a companion EXCEL spreadsheet for plotting. In addition, the spreadsheet contains thermal and material properties required as input data, as well as a calculator for determining the required heat transfer convection coefficient.
Runs under DOS only. Written by Richard Nakka.
THERMCAS.ZIP 112k DOS Freeware Version 1.01
This MS EXCEL spreadsheet may be used to create a flat pattern for a parachute gore. A gore is an individual panel that, when stitched together with adjacent gores, forms the canopy of a parachute. The user inputs the basic parachute diameter, as well as the number of gores desired (minimum of 4). The spreadsheet creates a table of coordinates as well as a plot of a single gore. When assembled, the parachute canopy is semi-ellipsoidal in shape (a "flattened" hemisphere). This form of canopy is more efficient than a hemispherical canopy, in that less material is required to provide equal drag.
Written by Richard Nakka.
PARAPAT_V1.1.XLS Version 1.1 (June 2016) 75kbytes EXCEL 97spreadsheet Freeware
PARAPAT_V1.1_BG.XLS 49kbytes EXCEL spreadsheet Bulgarian language version of PARAPT_V1.1 translated by George Andonov. Freeware
Parachute Gore DXF Generator
This is a handy, easy-to-use application that generates a parachute gore pattern in DXF file format. DXF is an open-source 2D drawing format. This allows a full-scale gore pattern to be printed using a standard CAD printer. This application plots gore pattern for both elliptical and toroidal parachutes. User can choose number of gores that make up the chute, and can choose either centimetres or inches.
Parachute Gore DXF Generator screenshot
A relatively simple-to-make beam-type loadcell may be designed by use of this Excel spreadsheet. The user specifies the dimensions of the loadcell body (basically, a rectangular block of metal) and the size of hole to be drilled through the body, in order to achieve the desired load capacity. The only other materials required are one or two strain gages, and suitable adhesive for mounting such.
Written by Richard Nakka.
LOADCELL.XLS Version 1.10 210 kbytes EXCEL spreadsheet Freeware
The most time consuming step of machining a rocket nozzle is the process of boring out the conical convergent and divergent passages. In particular, the divergent passage, which has a greater bore depth and more shallow angle. This step may be eased significantly by first drilling out these passages using a series of incrementally larger drill bits. The required drill bit sizes range from the throat diameter to the entrance (or exit) diameter of the nozzle. This operation results in a "stepped" profile which may then be bored to the final smooth profile with a standard boring bar tool. This spreadsheet is intended to aid this drilling operation by supplying the required drill depth for each drill bit size.
Written by Richard Nakka.
NOZLBORE.XLS Version 1.11 375kbytes EXCEL 2000 spreadsheet Freeware
NOZLBORE_BG.RAR 308kbytes EXCEL spreadsheet Bulgarian language version of NOZLBORE, translated by George Andonov. Freeware
Step-drilled divergent passage of A-100M nozzle.
A boring tool is then used to finish the contour.
This spreadsheet computes the Kn (burning-area to throat-area ratio) for a Pseudo-finocyl propellant grain. A Pseudo-finocyl grain configuration consists of a cylindrical grain with a circular bore, from which a number of fins extend radially (similar to a star-grain). Five independant geometric variables allow for great freedom in tailoring of the Kn profile. Such a grain may be fabricated by casting with a suitable mandrel, or by drilling the core, then cutting the fin slots.
Written by Richard Nakka.
PFC-BURN.XLS Version Beta-1 165kbytes EXCEL 2000 spreadsheet Freeware
PFC-BURN.RAR 72 kbytes Zipped EXCEL spreadsheet Bulgarian language version of PFC-BURN, translated by George Andonov. Freeware
Pseudo-finocyl grain cross-section. Example Kn chart.
Delaney/Nakka Ejection Charge Calculator
Simple to use Windows calculator that computes the mass of Black Powder needed to produce a specified pressure within a rocket parachute compartment. The resulting force tending to eject the nosecone or to separate the rocket sections is also computed.
Software written by J.Delaney
Help written by Richard Nakka
EjectionChargeCalculator.zip Version 1.3 1.4Mbytes MS Windows Freeware
This Excel spreadsheet computes the actual mass density of a sugar-propellant grain based on user input values of grain geometry and mass. This is compared to the ideal mass density by computing the ratio of the two densities. This provides the experimentalist with a "densitometric quality" assessment of a propellant grain. A good quality grain, one with minimal porosity and few voids or other flaws, will have a ratio close to one. A porous grain or a grain with hidden voids, for example, will be marked by a significantly lower density ratio. The usefulness of such a check is apparent when one considers that propellant burn rate and Kn profile can be strongly affected by such grain deficiencies. In extreme cases, a CATO could result from a grain with degraded densitometric quality.
Written by Richard Nakka.
GRAINDENSITY.XLS Version 1.00 40kbytes EXCEL 2000 spreadsheet Freeware
GRAINDENSITY_BG.RAR 13kbytes Zipped EXCEL spreadsheet Bulgarian language version of GRAINDENSITY, translated by George Andonov. Freeware
The use of o-rings is an ideal means to pressure seal a rocket nozzle or bulkhead. O-rings are inexpensive, simple to incorporate, and are highly reliable. However, it is important to choose the correct size o-ring for a given application, and to have the correct size gland (groove) into which the o-ring is seated. This Excel spreadsheet selects the appropriate sized o-ring based on user input values of casing and nozzle diameters, based on ARP 1232 specifications. Updated for 010, 100, 200 & 300 series (1/16", 3/32", 1/8" & 3/16") o-rings .
Written by Richard Nakka.
O-RING_2.4.XLS Version 2.4 872kbytes EXCEL spreadsheet Freeware
An extremely useful "open-source" (GNU GPL) software for reliably converting documents to Acrobat PDF format. Excellent for publishing articles for on-line format or for e-mailing. Can be used with any document software (examples: MS Word, MS Excel, Paint Shop Pro, etc.). Easy to use -- instead of printing to a device, you simply print to PDF Creator.
PDFCreator Version 0.9.3