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 Hints and Tips
Building and launching a model rocket is not difficult.
However, it is different than most any other class activity you have ever offered.
If you and your students have never built a model rocket it can seem daunting, even
with detailed instructions. After years of experience teaching model rocketry to
kids, certain areas have highlighted themselves as areas of concern or areas that need a
bit more guidance.
This section hopes to provide that guidance and to help you
in presenting model rocketry to your class. Broken into distinctive sections, it is
strongly recommended that you read all of these items before beginning your class.
The menu bar above will bring you to hints and tips that are specific to each of our Skill
Level 1 kits. Below are some hints and tips that are general in nature and apply to
most model rocket kits.
First is a summary list of common "got'cha's" that
you should be aware of and help guide your students to success. Some of these are
generic and apply to any model, others are more specific, but you will know when they
apply based on the kit you are building.
Summary assembly concerns:
- Razor knife safety - If your particular build
requires the use of a razor knife, it is important that you spend a portion of your class
describing knife safety with an emphasis on the penalties of careless use of the knife.
We suggest that you make a point in pointing out how sharp they are, how
easily they can cut and that any horse-play will be dealt with promptly (I usually take
the knife from the guilty party for the remainder of the session)
- Launch lugs missing. This can be attributed
to the idea that it is such a small part, how can it be that important. It is
important, in fact critical. Be sure that it is installed, straight and then not
clogged with paint or glue
- Engine mounts assembled backwards. Make
sure that the engine block is at one end and that the engine HOOK sticks out beyond the
OTHER end.
- Engine mounts glued IN backwards. Make
sure that the end with the engine hook is coming out the bottom of the rocket or, in the
case of mounts without hooks, that the engine BLOCK if facing forwards (top).
- Engine mounts not glued in. Or glued in with
an inadequate amount of glue. I have had students and teachers alike install the
engine mount without glue because the fit seemed "tight enough" to not need
glue. Wrong. Without adequate glue and filets, your rocket will sit on the pad
as the motor (mount and all) come shooting up out of the top of the rocket as can be seen in this
photo.
Summary launch concerns:
- Motor doesn't ignite: Usually the result of
one of three problems:
- Shorted igniter: If the wires of the igniter
or the micro clips touch each other the igniter will fail. The tricky part is that
the wires may short out under the plug inside the engine nozzle and be hard to see until
after you remove the igniter.
- Broken connection: If the fine wire tip of
the igniter is broken inside or if the micro clips are not connected or are very dirty,
this will cause an open circuit and cause a failed ignition. NOTE The
Continuity Lamp on your launch control is designed to check for JUST this
condition. If you engage the continuity lamp but it does not light, then you have a
"Broken connection" someplace along the line and your rocket will not launch.
- Inadequate power supply: If you are using dry
cells and/or less than 12 Volts you may start to experience problems with it taking longer
and longer for the rocket to ignite. The solution is fresh batteries or to switch to
a different power source. We recommend the use of your car battery.
- Parachute or streamer burns up on deployment: You
either didn't use recovery wadding, or not enough of it. Also, it is important that
the wadding be packed loosely and not squeezed into a tight ball.
- Fin broke on landing: This is a common
problem that, in some cases, is unavoidable. The good news is that you BUILT the
rocket, it should be an easy matter to REPAIR the rocket. Several things that you
can do to mitigate this problem is to launch in areas with softer surfaces (grass), pack
your parachute CAREFULLY so that it fully deploys, apply STRONG glue filets to all fins to
help hold them on.
The following sections cover these items, AND MORE, in
greater detail.
Detailed Construction/Assembly hints and tips:
- First, if at all possible, it is recommended
that you construct a model yourself before presenting to a class. This will go a
long way towards giving you the confidence you need while teaching. If you can not
do this, at least consider building one at the same time as your students.
- Second, make sure you are prepared for
construction by having all of the tools and materials ready for each student so that you
don't have to stop in the middle of your lesson to get something. You can review REQUIREMENTS for more information on this.
- The rest of this list covers basic construction tips. If
you look just below the navigation buttons at the top of this page, you will see
buttons for each of our Skill Level 1 model rocket kits. Clicking on these buttons
will provide you with additional tips about that specific model kit.
- Basic Construction:
- Test fitting: In every case where you have to
apply glue to a hidden area (like inside a body tube) and slide something into the glue,
it is STRONGLY recommended that you test fit the part and PRACTICE the step before you
apply glue. Such testing and practice can make the difference between success and
failure.
- Use adequate glue. Too much or too
little is not a good thing. When the instruction calls for a "bead of
glue", you should apply a line of glue that is about 1/8" wide in the area
indicated. If it calls for a "film of glue", the entire area indicated
should be coated in a thin layer of glue. In either case, you should be able to
clearly SEE glue in the area indicated.
- Don't force parts. Sometimes there is
difficulty in getting a centering ring in place. Working carefully with the part
will yield a good fit. Forcing the part may cause damage.
- When gluing on centering rings, fins and some
other items, the instructions will ask you to apply a "glue filet". This
is a critical step and must be performed. To apply a glue filet, run a bead of glue
at the joint that is called out (for example, the joint where a centering ring touches a
tube) then use your finger tip to smooth this glue out. NOTE: It is
important that glue filets be applied to BOTH sides of the item when
possible.
- When gluing the Engine Mount into the body
tube (not applicable on some rockets) it is imperative that you:
- Wait until the Engine Mount assembly is completely dry
- Test fit the engine mount before applying glue
- Apply a LIBERAL bead of glue inside the tube,
as instructed
- Push the engine mount into place swiftly to
prevent it getting glued in the wrong place
- Apply a glue filet to the lower engine mount ring where it
touches the inside of the body tube.
- These steps are very important to make sure that the engine
mount is securely attached to the body tube and can take the stress of launch.
- Gluing fins - Gluing fins with white or
yellow glue can be very frustrating. More than anything else, allow ample time to
allow one fin to dry before apply another. This can be the most time consuming part
of model rocket construction. Here is a neat trick: Apply a bead of
glue to the root edge of the fin (identified in the instructions), and press this to the
body tube where indicated, then remove the fin. Allow the glue on the fin and on the
body tube to dry partially (it will start to become clear and have a "skin" on
it. Before this dries completely, apply a thin FILM of glue on top of the glue on
the root of the fin and re-apply to the body tube. You will find that the glue will
GRAB very quickly and hold your fin on much better while handling.
- Straight fins - The straighter the fin, the
better the flight. The easiest way to judge how straight your fins are is to look
down the length of the rocket body, from the back end, using the fin as you would the
sight on a rifle. If the fin is straight, you will be looking right down the center
of the body tube. Crooked fins are fairly easy to see this way and can be adjusted
before the glue dries.
- Launch Lugs - The launch lug is a critical
part of the assembly. Without the lug, the model rocket can not be placed on the
launch pad and can not be launched. You can verify that your launch lug is straight
the same way as you did for the fins.
- Shock Cord Mounts - Your shock cord mount
connects the body tube to the nose cone, holding them together while the parachute returns
your rocket after a flight. It is important that this be installed properly and
securely. When installing the shock cord and it's mount in the body tube, it is
important that the shock cord is trapped inside the mount as shown in the instructions,
then that this mount be glued into the body tube firmly, such that it lays as flat as
possible inside the body. Mounts that stick up will interfere with the deployment of
your parachute and may result in a weak connection. The other end of your shock cord
needs to be securely tied to the screw eye on the nose cone.
- Parachute - First, the string supplied for
your parachute (not applicable on kits that use a streamer) is 96" long. This
needs to be cut into 3 equal pieces of 32" each. From there, the best way to
assemble the parachute is to place the provided tape disk onto the parachute, in the 6
corners as indicated, then to punch a hole in the center of each tape disk with a hole
punch. You then tie one end of one string through this hole and the other end of
this same string through the next hole in the parachute. repeat with the remaining
two strings. You then pinch the center of the parachute and gently tug at the lines,
forming the parachute into a spike. The lines should form 3 even loops. These
are gathered up and tied to the screw eye on the nose cone, with the shock cord.
Finishing your model:
- Be sure your work area is clean and protected from paint
spills
- If using aerosol paints or plastic model paints, be sure to
have adequate ventilation
- Have all clean up materials readily available
- Wear old clothes in case of accidental spills
- When applying spray (aerosol) paints, several very thin
(light) coats is much better than one thick (heavy) coat. Allow each coat to dry
20-40 minutes before applying a new coat. If masking to paint other colors, let the
first color dry completely (3-6 days) before applying masking tape.
- Make sure that you do not accidentally *glue* your nose cone
to the body tube with the paint. It is recommended that you remove the nose cone and
paint it separately. Be sure to protect the nose cone shoulder before applying
paint.
- Make sure that you do not accidentally plug up your launch lug
with paint. Clean the lug out completely if paint does get inside of it.
- Be sure to clean up your work area, tools and yourself when
complete.
Preparation for flight:
- It is recommended, as a part of the kit assembly, that you
explain to the students how to prepare their model for flight. When this is repeated
at the launch, it will serve as a refresher and will make more sense to your students.
- As with construction, make sure that you have everything that
you need so that you don't have to interrupt your class while looking for materials.
- Provide each student with their motor and igniter
and plug, instruct them how to install the igniter and plug then how to
install the motor into their model, then have them do the same.
- Provide each student with enough recovery wadding
to fill the body of their rocket about 2 times more than the width of the model (e.g.: the
Rhino is 1.637" in diameter, so you want enough wadding to fill the body tube about
3" - 3.5". NOTE: Do NOT use
tissue paper as this is a fire hazard. Use only model rocket recovery wadding
(available from your hobby shop) or cellulose insulation (available from your local home
improvement store)
- Have you students remove their nose cone and recovery device.
LOOSELY pack the recovery wadding into the body tube.
- Parachutes - Have them pack their parachute
by pinching it in the center, and gently pulling on the lines to form the parachute into a
spike. They would then fold the parachute into a thinner spike, then fold it in the
other direction to make a package small enough to fit LOOSELY into the rocket. If
the parachute is not loose, they need to refold it.
- Streamers - Fold the streamer in half, then
again and again, until it is about 4" long. Then firmly roll the streamer up
and loosely wrap the single shroud line around it. The streamer should fit loosely
in the body tube.
- Placing the rocket on the pad - Remove the safety key from
your launch controller or disconnect the battery. Have your student slide the launch
rod through the launch lug, and slide the model all the way down to the bottom of the rod.
NOTE: If there is glue or paint in the launch lug, you will need
to clean this out first! Once seated on the pad, spread the leads of the igniter and
hook up the two micro clips. NOTE: Be sure that the micro clips are
not touching each other or the blast deflector. Shorting of the clips will result in
a misfire.
- Angle the pad, as appropriate, based on field size and wind
conditions. NEVER tilt the pad more
than 30 degrees from vertical.
- Have everyone clear the launch area, hook up your battery
and/or install the safety key, give off a good loud count down and push the launch button!
I find it much more fun to get the entire class hollering out the count down!
- It is also recommended that the students recover their own
models so that they do not cause damage to someone else's model.
At this time we encourage you to review additional kit
specific hints and tips if you have selected one of our skill level 1 kits for your class:
If you have any additional questions, please do not hesitate
to contact us directly. Our goal is to help you be successful and to have fun with
your group! You can send inquires to:
FlisKits, Inc.
Education Dept
6 Jennifer Drive
Merrimack, NH 03054
or send us an email at:
sales@fliskits.com
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