Expert: Dave Landgraf - 7/31/2009

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)

I live in Hickory Hills Illinios


ANSWER: Hi Alex,

Everyone would like to know where to buy motors at lower cost! It is going to take a little looking around on the internet to find a store that has what you want in stock, at a decent price, and doesn't charge an arm and a leg for shipping (and special handling charges for hazardous materials). There are some stores that get it right and do not add HAZMAT fees, and if your order is large enough they don't even charge for shipping. Do a little shopping and check websites (presented in no particular order) like:
http://www.acsupplyco.com/estes/engines.htm (AC Supply)
http://www.ehobbies.com/rocketry-rocket-motors.html (eHobbies)
http://www.redarrowhobbies.com/estes_model_rocket_engines.htm (Red Arrow)
http://www.redarrowhobbies.com/quest_model_rocket_engines.htm
http://www.bellevillehobby.com/index.asp?PageAction=VIEWCATS&Category=220 (Belleville)
http://www.bellevillehobby.com/index.asp?PageAction=VIEWCATS&Category=208
http://www.a2zhobbies.com/estes_rockets.html (A to Z Hobbies)
http://www.hobbylinc.com/prods/tc.htm?g+rocket+motors (HobbyLinc)
https://www.discountrocketry.com/model-rocket-engines-c-9_38.html?osCsid=122292dfea8c33badad222400b018169 (Discount Rocketry)

The A6-4 motor that you are looking for is a Quest product. You should check their website for bulk prices, and re-visit often. Quest recently had a sale on all their products, and could well repeat it in the future. They have some great stuff!
http://www.questaerospace.com/items.asp?Cc=MotorVP&iTpStatus=0&Tp=&Bc=
http://www.questaerospace.com/items.asp?cc=MOTOR&Bc=
http://www.questaerospace.com/index.asp#

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.

More information can be found at:
http://www.ninfinger.org/rockets/nostalgia/alpha00.html
http://www.esteseducator.com/Pdf_files/POSTER%2084816A-2.pdf
http://www.esteseducator.com/Pdf_files/Engine%20ref.pdf
http://www.esteseducator.com/Pdf_files/Estes%20Model%20Rocket%20Engines.pdf

I hope that tells you what you want to know!

Dave Landgraf