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 QUESTION: I was wondering, where can i buy cheaper A6-4 rocket engines?
I love to launch rockets but its expensive,
And also, from someone on this site they said something about a rocket club
would you be able to find one for me (or give a site to find one)
If you want to pick up motors locally (and quickly), you may be able to find a selection of motors at stores like Hobby Lobby and Michael's crafts. Both of those stores offer discount coupons from time to time (check their websites on Mondays for any coupon offers that run for the week). Many of the stores in those chains stock three-packs of 18mm motors, four-packs of 13mm motors, and might even stock D and E motors. With a 40 percent discount, these motors become quite reasonably priced! If the store has an Estes "Flight Pack" on the shelf, you can get 24 assorted 18mm motors for around $55 normal price, or around $33 sale price. Getting motors for around a buck-40 apiece is about as good as you're going to find.
To locate a local club, you might try asking the local hobby shops if they know of any active clubs. Sometimes a local school will sponsor a rocket club, so when school begins again in a few weeks you could call some of the schools in your area to check (best place to start might be the science teachers). Don't forget to check the NAR (National Association of Rocketry) website and look over their list of rocket clubs at: http://www.nar.org/NARseclist.php
And you can always get lots of help quickly at model rocketry websites like: http://www.rocketryforum.com/index.php (The Rocketry Forum) http://www.oldrocketforum.com/ (Ye Olde Rocketry Forum) http://www.rocketryplanet.com/forums/ (Rocketry Planet)
and several others. These website forums are free to join, free to use, and have many experienced rocketeers who are usually happy to help you with rocketry questions or problems.
I hope that information helps you. Have fun with your rocketry projects!
Dave Landgraf
---------- FOLLOW-UP ----------
QUESTION: Thanks so much!!!!!!!!!!!!
And what will happen if i dont use a motor recommended for the rocket?
Answer Manufacturers of model rocket kits are usually pretty good about giving you several rocket motor choices. They often list this information on the outer packaging (or visible through the plastic bag) so you can read which motors you need while you are still in the store and have a chance to pick out those motors.
If you select a somewhat lower-powered motor (like an A, or 1/2A) the rocket will fly a little lower, and will not drift away as far on a windy day.
If you select a more powerful motor (like a C) the rocket will fly significantly higher.
The trick to proper motor selection is reading the manufacturer's recommendation and choosing one of the motors listed. Many people choose a motor with a different last number (after the "dash" mark, in the motor label code). They choose a motor with a bigger number and think somehow that it is more powerful. This is one of the biggest mistakes you can make in motor selection.
The "power" of the motor is shown in the first letters and numbers of the label. These show total motor power and average thrust. The last number only shows the length of time (in seconds) that the delay charge burns before the ejection charge goes off.
If your model rocket is recommended to use a A8-3 motor, that motor is designed to deploy your recovery system near the maximum altitude of the flight. If you instead selected an A8-5 motor, the motor would deliver the same total power and same average thrust and would fly no higher, but the delay charge would smoulder for five seconds---way past the maximum altitude, and probably ending when the model rocket had fallen most (or all) the way back to the ground. Then, when the ejection charge fires too late, the recovery system would probably not have enough time to open and slow the rocket and it would crash into the ground. If you are lucky, ground is all it would hit. That would be bad enough, and your rocket would likely be ruined. If there are many people in the area you will risk having your rocket strike one of them (this is not a good thing).
A simple solution would be to read the list of recommended motors and limit your motor choices to that list.
