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Monday, 4 September 2017

More Rocketry Tips for Beginners

If you're thinking about the Rocket hobby, just getting into it, or need a refresher these tips will be a great help. If you're in the Calgary area you can join the Calgary Rocket Association. Click Here for their website.

Please keep in mind:  
Model rockets are not toys - you can't simply plug them in and turn them on expecting them to work. They can be dangerous if not handled properly and taken seriously. They are miniature real rockets and a number of things need to work perfectly and come together at the right time to ensure a proper launch. 
Note unless otherwise stated references are to Quest or Estes model rockets (as opposed to Advanced, High Power or Amateur rockets and these tips are only our opinion through experience and research). 

Your Rocket
Don't use double sided tape or self-adhesive tape to attach shroud lines to the canopy or streamer. These can clog the body tube and will eventually lose their stickiness. Instead use paper reinforcing rings. Glue them on your recovery device, puncture though the centre hole, thread the shroud lines through the hole and tie onto the canopy with a double knot. Pull the lines firmly to make sure they won't come off when the recovery device deploys.
Using a permanent marker, write contact details on your rocket to increase your chances of getting the rocket back should you lose it. 

Make sure the launch lug is strictly parallel to the body tube and there are no stickers/decals or other things that can catch or jam; in front of or behind the lug. Note a poorly aligned body tube glued to the fin unit can also cause a jam on the launch rod).
If the launch lug is molded to the plastic fin canister, make sure any 'flashing' is removed from the inside of it.
The nose cone must be an easy but snug fit into the body tube, if it’s too loose the cone may release when the rocket slows down. Use masking tape around the nose cone if it’s too loose. Hold the cone tightly in one hand and pull on the shock with the other, to ensure your knot won't fail when the recovery device deploys.
Make sure when gluing the engine mount together that excess glue doesn’t end up inside the engine mount. This will block the fitting of the motor. Wipe away any excess glue immediately. And don't forget to glue the engine mount in - yes it does happen! 

You must use wadding and it must be flameproof. Toilet paper, paper towel and tin foil will not work and will cause your rocket to burn up, explode or melt.

The Engine
Make sure the engine is the recommended letter/number combo for your model –the letter is the engine strength, the first number is how many seconds of thrust and the last number is the seconds until the shoot deploys. Check your instructions to get the recommended engine per your kit's instructions. Using the wrong engine delay will cause you a lot of grief! The engine must be a slip fit and slide easily into the engine mount. Never force the engine into the mount. Get used to checking the engine nozzle (the hole where the igniter is inserted). It will either be clay (white) or ceramic (black) - a black ceramic type nozzle signifies a European manufactured engine and will warn you that the delay time (coasting time) may be significantly longer than expected - a 3 second delay can be more like 5 seconds, a 4 second delay can be more like 6 seconds, and a 5 second delay more like 7 seconds. Adjust the angle on your launch rod upright accordingly. Taking a long walk is better than a destroyed rocket!

The Igniter
There are two types of igniter - the copperhead and the nichrome igniter. The first looks like one piece of copper with a black tip (the squib), and the second has two silver or copper wires. The nichrome igniter has less resistance than the copperhead and requires less current to fire, however it is brittle and fragile and so it is best to use masking tape across the nozzle. The squib must be touching the propellant - (the black stuff you can see inside the nozzle). Using a plug can cause the wires to come together causing a short. And that's also why you don't remove the paper tape on the nichrome igniter which keeps those wires apart! While the copperhead igniter is 'bulletproof' it requires more current to fire, so your batteries must be new and of the right voltage. 

The Launch Controller
The battery (s) you use in your launch controller are often the sole factor of whether or not you have a successful launch. You must use the proper battery(s) and they must be new batteries. Lithium and alkaline batteries, which together have a voltage rating of at least 6v-9v, are the only batteries suitable for model rocket launch controllers. Lithium batteries are the best, rechargeable batteries can give you a lot of grief, so don't use them.
Insulating one jaw of each alligator clip (with masking tape) is recommended. 'Flip' each alligator clip when attaching to the igniter so that one uninsulated jaw is touching one side of the igniter and the other uninsulated jaw touches the other side. Lightly sand your safety key and always keep it clean.

The Launch Pad
Pin down your launch pad with tent pegs, especially on a windy day. Also, make sure the launch rod is a tight fit in its mounting hole where it fits into the base of the launcher. If using a two piece rod, the two pieces must be a tight fit into each other and have no kinks. You don't want your rocket taking the launch rod with it, when it lifts off! Sand the rod lightly before launch and coat it with a thin layer of petroleum jelly (Vaseline). Always use the 'stand off'' which ensures igniter clips do not touch the jet deflector plate and cause a 'short'. If you lose the 'stand off'' use a burnt out engine instead. Test fit your rocket on the rod to ensure it slides freely - very important Make sure the rod safety cap is replaced on the rod after each launch.
Upgrade Tip your two piece rod can be replaced by one piece rod, .9 m to 1 m long, 3 mm in diameter. Stainless steel rod is best, however piano wire from a hobby shop will do the job.

Ready to Launch
The launch circuitry can be tested by installing the igniter, battery, and safety key (not on all launch systems), and momentarily pressing the launch button. The igniter should glow red hot. Release the launch button immediately as the igniter begins to glow, otherwise it will soon melt and have to be discarded.
When the rocket is seated on the igniter make sure it’s fully inserted and centered in the nozzle of the rocket engine. Just remove the launch rod, seat the rocket correctly on the igniter and then carefully re-instal the launch rod. Note due to the differing weight and aerodynamic shape of each of the rocket, not all models will achieve the expected altitudes and some may surpass it. Rockets with AT, A and B letters in the engines are great for beginners and first  launches, larger engine sizes such a C and D should be only used by intermediate to expert and a license/permit is required for any engines larger than E.

Looking for more help and great tips? Check out our other Rocketry posts!

4 Tips to Flying Model Rockets- use/copy the engine chart 

Rocketry Tips- Recovery Wadding, Why Do I Need It? 

Next week: Car model tips!

Chinook & Hobby West
"Where the Fun Begins!"
ph: 403-243-1997
Twitter: @HobbyAndToy

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