AboutDave Landgraf Expertise I will be happy to take on questions about low-power rocketry in general, including rocket design, operating characteristics of blackpowder motors, low-power motor selection, rocket construction, aerodynamics, parachute and streamer duration competition, boost glide (and a little rocket glide), egg loft, altitude competition, and scale competition. I can help you with Barrowman stability calculations, but I am not a rocksim user. I know the basics of mid-power rocketry and small composite motors but I don't fly them much (I'd rather stretch my money by sticking with low-power). I believe I can explain many concepts in a way that just about anyone can follow (and maybe even over-explain?). I absolutely do not mind "newbie" questions one bit; the only bad question is the one you don't ask!
Experience I have flown model rockets for some 40 years, including a few early years of NAR competition. I have been active at the local club level as well as in the NAR. I enjoy designing and developing unconventional designs (the kind of thing you look at and say "it won't fly!").
Organizations National Association of Rocketry
Publications Model Rocketry (magazine)
Education/Credentials I am an aerospace engineer who has worked professionally in the field for over 30 years. I have worked often with local school, church, and scout groups to lead introductory build-n-fly sessions.
Question How does weight effect altitude on rockets, and can you give me sites pertaining to your answer or evidence?
Answer Hi Bobby,
In general, a heavier rocket moves more slowly and does not fly as high as a lighter rocket when they both have the same air drag and are both powered by the same size motor. A heavier rocket will have a smaller acceleration (or, how fast the speed changes), and for the same thrust duration, will end up with a smaller final velocity. When the motor burns out and the rocket starts coasting to a stop, the pull of gravity slows the rocket to zero more quickly. A lighter rocket will build up to a higher velocity and will travel higher while it is slowing down to zero airspeed.
If you want to do a little research for yourself, your science teacher can help you learn about basic physics. There is a little algebra involved but it is rather simple. You will want to look for equations like:
F = m x a
(Force = mass x acceleration)
and:
(V)final = (V)original + a x t
([final velocity] = (original velocity) + acceleration x time )
Or, you can go to your local public library and borrow some books on basic physics. Ask your librarian for help finding books that are suitable for your age and grade level.
