Birdie Rocket

Posted April 19, 2009

See the Rocketry page for additional notes.

A typical engine used to power the birdie rocket. This is a mini-engine, usually purchased in packs of four and are available at most hobby stores. The best prices are at Hobby Lobby or Michaels using a 40% store coupon.

Mini-engines are 1 ³/₄ inches long and ¹/₂ inches in diameter. Any mini-engine will work in a birdie, although the A-class engines will fly higher than the ¹/₂ A-class engines and cost about the same.

Detail of cardstock ring used to
secure bottom of engine tube.

1/2" and 1/8" inch steel punches
can be used to cut interior
holes on paper ring.
A full set costs about $20
on Ebay.

Detail showing alignment
of launch lug

Detail showing ignitor installed in engine

Engine installed in rocket;
wire ignitor installed
in engine

It's Spring and there are birdies in the air!
Building and Flying the Birdie Rocket

Model Rockets make a great cubscout activity. Cubbies will happily spend the afternoon chasing rockets all over a school playground -- just don't tell them they're getting exercise. The equipment needed to launch a model rocket can be purchased for about $20 at most hobby stores or constructed from a 2x4 and commonly available household materials. The trick is finding a model rocket design that

1. Can be built and flown by the average cubscout and his parents within the 1-2 hour timespan of a pack meeting.
2. Will fly well in spite of minor mistakes in construction.
3. Is relatively inexpensive.

The Birdie Rocket is built from a common badminton birdie. It is a stable design that is very forgiving of minor major construction flaws. The rocket itself can be constructed for under a dollar and can be flown multiple times. The non-reusable rocket engines cost $1.25 to $2.00 apiece depending on where you purchase them. These rockets have been used at the Buckeye District camporee and daycamps. With a bit of organization and good help, it is very easy to build and fly several hundred birdies in a day long event.

The birdie presented here updates a classic Estes design first published in the late sixties. It's available as a kit from Uncle Mike's Rocket Shack for about $6.00, but is easily scratch built for about 50 cents.

The birdie rocket has four parts (see diagram at left) and can be assembed in about 2-3 minutes using hot glue. Use a low temperature glue gun so you don't melt the birdie or blister any fingers. Hot glue is not very strong, so make sure you use enough.

Birdie with the
engine installed

Put glue in the nose of the birdie to install the engine tube. Push the tube into the birdie and wait a minute or so for the glue to set.
Slip the paper ring onto the engine tube -- make sure to align the slot (or small hole) with a slot in the birdie, so the launch lug can be installed straight and parallel to the engine tube.
Run a bead of glue

Between the paper ring and the birdie
between the paper ring and the engine tube
Keep the hole for the launch lug clear of glue.

Install the launch lug tube -- slip it through the slot (or small hole) in the paper ring and out through the front of the birdie. Glue the launch lug in place. Ideally

The front of the lug should rest on the nose of the birdie
The lug should be parallel to the engine tube

Bill of Materials

Item	Source	cost
Birdie	Purchase in bulk online, e.g. sportsonline.com	0.25
Engine Tube	Balsa Machinging Service, order tube size T5-34, $1.50 as of April '09. This is a 34" tube with 1/2" diameter. Cut it into 19 1.75" lengths. A bandsaw will make quick work of cutting the tubes.	0.08
Paper Ring	Trace the pattern (left) onto heavy card stock (the kind used to matte pictures). Cut out the disks with scissors and punch the holes using a hammer and 1/2" and 1/8" steel punches. The holes can be slightly out of position without causing serious problems.	0.05
Launch Lug	The launch lug is a 1.5" length of paper straw 1/8" in diameter. Plastic straws don't work very well. Paper drinking straws are perfect but are no longer manufactured. You can buy them by the box as collectables on Ebay -- $3 - $12 for a box of 100 6" straws. Another source is Chenille Kraft Company Art Straws. If you can find a vendor, you can get enough paper straws for the rest of your scouting career for about $30.	0.05
Hot glue stick	Don't be stingy with glue. Budget one 4" glue stick for every 2 birdies and have extra on hand.	0.05
engine	Engines are good for one flight and are available at most hobby stores. The best prices seem to be at Michaels and Hobby Lobby with a store coupon. Expect to pay anywhere from $1.20 to $2.00 depending on your luck. Engines come with ignitors.	1.25

Tips for running the activity

Make sure you've built a couple birdie rockets before the event so you know the construction method before you have to explain it to scouts and parents
Have extra materials on hand. Birdies are cheap and the neighborhood kids will want to launch one too.
Make sure you check out your launcher before the event. A birdie rocket can be launched from the end of your driveway without alarming the neighbors.
Rocket engines are ignited electrically using a wire ignitor which usually works the first time. Have extra ignitors on hand for when they don't. Nichrome wire (available at hobby stores) can be used as an ignitor if your battery is big enough.
The bigger the battery, the better. Emergency batteries for starting cars work real well. The Estes launchers that use AA batteries are not reliable enough for large groups.
Get your parents involved. Anyone can build a birdie, so put half a dozen parents to work helping the kids with construction. The other bottleneck is getting the ignitor installed in the engine and hooked up to the battery. Having the parents set up several rockets at a time will speed up the event and help keep the kids focused.
Have some fine steel wool along to clean the launch rod and the alligator clips that connect to the ignitor.

Safety Disclaimer

Model rockets activities in Scouting are described in the Webelos handbook and in the Space Exploration Merit Badge Handbook. While very effort has been made to provide accurate information as part of these model rocket discussions, the maintainers of Worthington Scouts cannot be held responsible for your rocket launching activities. In particular, it is your responsibility to carry out any necessary risk assessments and to implement appropriate safety measures.