Need help with the mechanical calculations
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It sounds like you're making the motor yourself? If so, then you'd need to characterize it in order to simulate a flight with your payload.
OpenMotor is pretty good for the first task, and OpenRocket for the second.
Note that discussion of particular motor recipes is not permitted on the open forum. Welcome aboard!
OpenMotor is pretty good for the first task, and OpenRocket for the second.
Note that discussion of particular motor recipes is not permitted on the open forum. Welcome aboard!
...Which calculations? Altitude predictions? Needed motor performance? Stability?
This question and your other statement that you are new to rocketry doesn't lead me to think you have any business making or using a 7 kg motor. I would strongly advise you start smaller - MUCH smaller - For your own safety and that of those around you.
Along with OpenRocket, "The Handbook of Model Rocketry" by G. Harry Stine is probably the best place to start answering your questions.
If you want to make your own motors, "Experimental Composite Propellant" by Terry McCreary is a good go-to.
This question and your other statement that you are new to rocketry doesn't lead me to think you have any business making or using a 7 kg motor. I would strongly advise you start smaller - MUCH smaller - For your own safety and that of those around you.
Along with OpenRocket, "The Handbook of Model Rocketry" by G. Harry Stine is probably the best place to start answering your questions.
If you want to make your own motors, "Experimental Composite Propellant" by Terry McCreary is a good go-to.
The motor will be provided by our university it is a project me and my friends started because we are considering to enter a contest and we just need some kind of a guide to get us started.
I'll look to OpenRocket thank you guys for your answers much appreciated
I'll look to OpenRocket thank you guys for your answers much appreciated
Makes more sense if you're doing this under supervision of a university. Good luck.
Thank you.
If you’re allowed to choose a commercially available motor, I’d suggest looking at Thrustcurve.org. The site has information on an extremely wide variety of commercially available rocketry motors. The Aerotech M2100G has a mass of 6,198 grams and delivers 7,802 Newton-seconds of total impulse. I don’t pretend to know much about Level 3 high-power rockets but something like that sounds very worthy of consideration.
The engines that we can use are Cesaroni M2150 M1545 M1675 M2020. I was thinking about using M1675. I would love to hear your suggestions on this.
I’ve never flown CTI for anything, much less for anything of this scale. I’m sure this will be plenty of power, though. These are all 75mm motors or larger, and aren’t affected by the catastrophic failures (“CATOs”) that have been affecting their 54mm motors.
For that kind of altitude, you will want dual deployment. A drogue at or near apogee to destroy the rocket’s ballistic properties but still lower it fast enough to avoid drifting out of the range, and a main deployed at <1000 ft to avoid damaging the rocket on landing. There are specialty altimeters available that can measure your altitude above your launch site and activate pyrotechnic charges at pre-programmed stages of flight to accomplish this. Some even allow backup charges to be set in case the primary ones doesn’t successfully eject the chute.
OpenRocket supports simulating rockets like this to get stability margins, apogee, rail clearance speed, angle of attack, moment of inertia, maximum speed, maximum acceleration, Mach number, descent speeds, drift distance/direction, and several dozen other flight parameters.
For that kind of altitude, you will want dual deployment. A drogue at or near apogee to destroy the rocket’s ballistic properties but still lower it fast enough to avoid drifting out of the range, and a main deployed at <1000 ft to avoid damaging the rocket on landing. There are specialty altimeters available that can measure your altitude above your launch site and activate pyrotechnic charges at pre-programmed stages of flight to accomplish this. Some even allow backup charges to be set in case the primary ones doesn’t successfully eject the chute.
OpenRocket supports simulating rockets like this to get stability margins, apogee, rail clearance speed, angle of attack, moment of inertia, maximum speed, maximum acceleration, Mach number, descent speeds, drift distance/direction, and several dozen other flight parameters.
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I strongly recommend that you go on the web to either the NAR or Tripoli web site and find the nearest club. Call the club Prefect and see if he can arrange a Mentor for your group. With a level 3 Mentor you should ace the project.
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Download OpenRocket and learn how to use it, including adding a motor file for the thrust curve of the motor that your university is providing. When used properly (which means weighing and measuring every piece carefully), you will get very good results out of it. Like any simulation, it's only as good as the data that you put into it.
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