John Ross
Active Member
- Joined
- Jul 18, 2020
- Messages
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New member John Ross here with my first post.
I was born in 1957 and started building model rockets in 1963, initially using Estes kits and components, and eventually, by the end of the decade, rockets with larger E and F motors from Flight Systems.
My dad had started teaching me woodworking skills when I was four years old, and model rocketry was a wonderful hobby to share with him until his death. In addition to being an amateur cabinetmaker, dad was also an experienced photographer, and with his help I took many photos with my Camroc, eventually some in color.
Dad got me a Cineroc when they first came out, and marveled at the footage we got. I still have it, and all the original packaging.
Dad also loved fireworks, and had displays on our hundred acre summer property on the Mississippi River 25 miles south of St. Louis. July 4 was my favorite holiday, even better than Christmas.
In August 1963, after I had been building and launching model rockets for several months, I was helping Dad set up a fireworks display for my cousin Katie's engagement party that evening, and I noticed him putting out some of the buzz bombs upside down. When I mentioned this, he considered for a moment, then said "By God, you're right. That's why some of them always just spin around on the ground. I never looked carefully enough." Then he held out the Bernz-O-Matic torch, and said "Make sure we've got everything set out right, then you light this show. I'll sit with the rest of the audience and watch."
I was thrilled.
After Dad died of pancreatic cancer in October of 1970, I pretty much stopped doing anything with model rocketry, but I kept shooting fireworks displays 1 to 3 times every year. I've now been doing that for over half a century.
In 2013 I sold my investment business to concentrate on writing as my profession, and spend more time on my other passions. I acquired the appropriate state and federal explosives licenses, dusted off my thermodynamics textbooks, and joined several fireworking forums. My main goal was to build rockets. Virtually no professional operators in this country use rockets in their public displays, so really good rockets are the one type of firework that is pretty much unavailable to buy in this country, regardless of what licenses you hold.
Before joining this forum, I pored through the rules, and could find no prohibition against talking about firework rockets. If I somehow missed such a rule, please delete this post, and I'll terminate my membership.
The reason I am making my first post to the forum in the Rocketry Electronics and Software section is that I own an Acme test stand, which records thrust and time data on the rocket motors I make, and will show predicted altitude data based on the total weight of the rocket. Thus, you can easily figure out what size ball or cylinder shell can be lifted to the desired height, and how many seconds of delay comp to use in the motor for the shell to explode at the rocket's apogee.
This brings me to the question I am posing today. Yesterday I downloaded the open source software OpenRocket. Unlike most rocket builders, I prefer to use fins instead of sticks, and launch my rockets out of large HDPE tubes. I felt that OpenRocket would be a much better tool than trial and error for determining stability levels of different fin dimensions for my rockets with various headings.
Getting OpenRocket to actually run on my computer took over an hour, and I still wish I had someone familiar with the program looking over my shoulder telling me how to do what I want. I have not been able to find a comprehensive "user's manual" to answer the two main questions that I have:
There is a large database of commercially available model rocket motors. Is there any way to create a database of homemade rocket motors, either using data acquired by my Acme test stand, or more crude methods that people have used, such as using video of kitchen scales to get an idea of duration and peak thrust?
If the moderators feel this post, and other discussions of homemade motors is not within the scope of this discussion forum, please delete it and accept my apologies for joining.
JR
I was born in 1957 and started building model rockets in 1963, initially using Estes kits and components, and eventually, by the end of the decade, rockets with larger E and F motors from Flight Systems.
My dad had started teaching me woodworking skills when I was four years old, and model rocketry was a wonderful hobby to share with him until his death. In addition to being an amateur cabinetmaker, dad was also an experienced photographer, and with his help I took many photos with my Camroc, eventually some in color.
Dad got me a Cineroc when they first came out, and marveled at the footage we got. I still have it, and all the original packaging.
Dad also loved fireworks, and had displays on our hundred acre summer property on the Mississippi River 25 miles south of St. Louis. July 4 was my favorite holiday, even better than Christmas.
In August 1963, after I had been building and launching model rockets for several months, I was helping Dad set up a fireworks display for my cousin Katie's engagement party that evening, and I noticed him putting out some of the buzz bombs upside down. When I mentioned this, he considered for a moment, then said "By God, you're right. That's why some of them always just spin around on the ground. I never looked carefully enough." Then he held out the Bernz-O-Matic torch, and said "Make sure we've got everything set out right, then you light this show. I'll sit with the rest of the audience and watch."
I was thrilled.
After Dad died of pancreatic cancer in October of 1970, I pretty much stopped doing anything with model rocketry, but I kept shooting fireworks displays 1 to 3 times every year. I've now been doing that for over half a century.
In 2013 I sold my investment business to concentrate on writing as my profession, and spend more time on my other passions. I acquired the appropriate state and federal explosives licenses, dusted off my thermodynamics textbooks, and joined several fireworking forums. My main goal was to build rockets. Virtually no professional operators in this country use rockets in their public displays, so really good rockets are the one type of firework that is pretty much unavailable to buy in this country, regardless of what licenses you hold.
Before joining this forum, I pored through the rules, and could find no prohibition against talking about firework rockets. If I somehow missed such a rule, please delete this post, and I'll terminate my membership.
The reason I am making my first post to the forum in the Rocketry Electronics and Software section is that I own an Acme test stand, which records thrust and time data on the rocket motors I make, and will show predicted altitude data based on the total weight of the rocket. Thus, you can easily figure out what size ball or cylinder shell can be lifted to the desired height, and how many seconds of delay comp to use in the motor for the shell to explode at the rocket's apogee.
This brings me to the question I am posing today. Yesterday I downloaded the open source software OpenRocket. Unlike most rocket builders, I prefer to use fins instead of sticks, and launch my rockets out of large HDPE tubes. I felt that OpenRocket would be a much better tool than trial and error for determining stability levels of different fin dimensions for my rockets with various headings.
Getting OpenRocket to actually run on my computer took over an hour, and I still wish I had someone familiar with the program looking over my shoulder telling me how to do what I want. I have not been able to find a comprehensive "user's manual" to answer the two main questions that I have:
There is a large database of commercially available model rocket motors. Is there any way to create a database of homemade rocket motors, either using data acquired by my Acme test stand, or more crude methods that people have used, such as using video of kitchen scales to get an idea of duration and peak thrust?
If the moderators feel this post, and other discussions of homemade motors is not within the scope of this discussion forum, please delete it and accept my apologies for joining.
JR
Last edited by a moderator:
Examples can be found on thrustcurve.org. Basically, they give the key statistics of the motor along with a thrust curve.
