There are lots of programs, including many commercial programs, that will predict the maximum altitude of a model rocket. There are some inexpensive altimeters out there also that can give altitude results when placed inside your model during flight. Are they trustworthy? I wasn't sure so I had an idea to see if I could come up with a LB program that would predict accurately (within 5%) the height of a model rocket. Of course this program is more involved than the others presented on this page so I needed some help. I got a great deal of help from Mr. John Fisher who lives in Merry Old England. I had the ideas of what I wanted to do and he developed the code that would get me there. I give all credit to him.
I knew published data was available for model rocket thrust curves. I was not sure how accurate this data was as I was concerned that companies that make the motors might tend to exaggerate the numbers. I began a series of tests using an analog to digital interface and a force probe to measure force and time data and integrated these curves to obtain impulse data for various rocket motors. I have to say that the published data is very close to my measurements. The first bit of code presented here represents a simple algorithm that will predict rocket altitude when average impulse is used from published motor data.
cogburn
May 23, 2012
There are lots of programs, including many commercial programs, that will predict the maximum altitude of a model rocket. There are some inexpensive altimeters out there also that can give altitude results when placed inside your model during flight. Are they trustworthy? I wasn't sure so I had an idea to see if I could come up with a LB program that would predict accurately (within 5%) the height of a model rocket. Of course this program is more involved than the others presented on this page so I needed some help. I got a great deal of help from Mr. John Fisher who lives in Merry Old England. I had the ideas of what I wanted to do and he developed the code that would get me there. I give all credit to him.
I knew published data was available for model rocket thrust curves. I was not sure how accurate this data was as I was concerned that companies that make the motors might tend to exaggerate the numbers. I began a series of tests using an analog to digital interface and a force probe to measure force and time data and integrated these curves to obtain impulse data for various rocket motors. I have to say that the published data is very close to my measurements. The first bit of code presented here represents a simple algorithm that will predict rocket altitude when average impulse is used from published motor data.