1. Bottle Rockets - B 2016-17 CeAnn Chalker ceann@chalker.org
Bro. Nigel Pratt
Jim Woodland

3. Disclaimer
This presentation was prepared using draft rules. There may be some changes in the final copy of the rules. The rules which will be in your Coaches Manual and Student Manuals will be the official rules.

4. What is Bottle Rockets? Teams -
design, construct & launch water rockets
to stay aloft
for greatest amount of time
while carrying a raw chicken egg
that survives impact

5. Event Parameters 2 Rockets are prebuilt by team members
Only 1 launch per rocket
No sharing rocket parts
Eye Protection #5 must be worn
One warning given

6. Event Supervisor Provides
Launcher
Water
Two Marked Grade A Large Chicken Eggs per team
(plus extras for breakage)

7. Construction – Pressure Vessel
The Rocket’s Pressure Vessel must be made out of a single 1-liter or smaller plastic carbonated beverage bottle
Label must be presented if removed
Inside diameter of nozzle of approximately 2.2 cm

8. Construction – Structural Integrity
Structural integrity of pressure vessel may not be altered. For example:
Physical damage
Thermal damage
Chemical damage
Safety check will be done

9. Construction – Attachments
Yes!
Only TAPE may be used to attach items to the Pressure Vessel.
NO GLUES of any type may be used on the Pressure Vessel.
Glue may be used in other parts of the rocket

10. Construction – Nose Cone
Nose of the rocket must be rounded or blunt at the tip.
The nose must be designed such that when a standard 2 liter bottle cap (~3.1 cm diameter x 1.25 cm tall) is placed on top of the nose, no portion of the nose touches the inside top of the bottle cap (see Figure 1).

11. Construction – Bottle Opening
All parts must be 5 cm above the level of the bottle’s opening
nothing may break this plane
no tethering allowed

12. Construction – Inserting the Egg
The Egg must be easily removed
Nothing may be adhered to the egg (e.g. glue or tape)

13. Construction – Design Restrictions
Rockets during launch or flight must not-
Become separated
Change shape
Deploy any type of recovery system
No parachutes!

14. Construction – Safety Restrictions
No metal may be used anywhere on the rocket.
No commercial model rocket parts.
No explosives, gases (except air), electronic devices, elastic, throwing, remote, chemical or pyrotechnics allowed.

15. Competition – Basic Details
Walk in or sign up event
Wear Safety Goggles
Students will add Egg, any amount of water, set on launcher, launch, and retrieve their rockets.
10 minutes to launch 1 or 2 rockets
(only 1 launch per rocket)

16. Competition – Loading the Egg
Teams are allowed to inspect and select the 2 eggs to launch
If a team breaks an egg before launch they may request another egg
Replacement eggs as of now will not receive a time penalty, this may change in the rules
Teams load their egg into the rocket
Reminder – nothing may adhere to the egg

17. Competition – Launching
Rockets launched using Launcher provided by supervisor
Only water/air pressure will be used for energy to the rockets
Maximum of 60 psi for launching
Once rocket is pressurized, no one may touch or approach the rocket

18. Competition – Timing
Timing begins when the rocket separates from the launcher.
Timing ends when any part of the rocket:
touches the ground or
rests on an obstruction or
goes out of sight
Rockets launched before time expires will be scored

19. Competition – Retrieval & Egg Examination
Teams will immediately retrieve each rocket
Remove the eggs in the presence of the Event Supervisor for inspection
Egg survival is defined as an egg leaving no wet spot on a paper towel

20. Scoring
Combined greatest time aloft of both rockets recorded to the nearest hundredth of a second.
If only 1 rocket is launched, the team receives the time for only that one launch.
Will be scored in either Tier 2 or Tier 3 based upon survival of the egg

21. Scoring – Tiers Tier 2: Tier 1: Tier 3: Launches with 2 surviving eggs
Launches with no surviving eggs

22. Violations Construction Violation – Competition Violation -
A Rocket with a Construction Violation will not be launched.
Competition Violation -
A Rocket with a Competition Violation will not be scored even if it has a time.
If a Team has one Legal Rocket, that Rocket will be ranked in the appropriate Tier depending upon the survival of the egg.
Note – With 1 rocket the best they can place would be in Tier 2.
If Both Rockets have violations the team will not be ranked and receive only Participation Points

23. Tie Breaker Tie Breaker
The better score of each tied team’s best rocket.

25. So, How DO you become a Rocket Scientist?

26. Research READ this Year’s SO Rules First! Search the Internet for:
“backslider”
“backglider”
“water rockets” as opposed to “bottle rockets”

27. The Bottle – MASS is Key!
ALWAYS remember: Keep MASS at a minimum!!! F=ma
Get a variety of CARBONATED 1 liter or smaller bottles from DIFFERENT companies.
You’ll be surprised at the variation of masses
Use non-carbonated bottle parts for your extension, nose cones, egg holder, etc.
these tend to be thinner and lighter weight
Trim away ANY excess parts that are buried in the rocket and will not affect it in any way
Do not cut or damage the pressure vessel!

28. The Bottle – More ways to reduce MASS
Remove the labels (keep them – know which label goes with what rocket)
Clean off the ALL the glue, but don’t scratch the rocket
Build CLEANLY! The smoother the sides of the rocket, the better
Use as little tape/glue as you can – both for mass and aerodynamic clean builds

29. The Fins – Don’t forget MASS
Use 3 Vertical Fins evenly spaced
suggestion: thin styrene sheets, thinner bottles, card stock, balsa or bass wood They do not have to be large!!!
Remember the 5 cm “No Fin Zone!”
Cut out a piece of non-carb bottle that matches the curve of your pressure chamber.
Glue the fin to the piece and then tape it to the pressure chamber!

30. The EGG… and It’s Holder (MASS again!)
What material for the holder?
bubble wrap, plastic egg suspended, foam with egg cutout, air cushions, balloons, etc…
Location?
“….must be easily removed”
Practice with plastic eggs (with masses between 57 – 60 g) for correct stability of the rocket.
Transitioning to real eggs, use zip lock bags to facilitate clean up.

31. Rocket Stability is Vital!
Center of Gravity (CG)
Center of Pressure (CP)

32. Center of Gravity (CG)
Determine the CG by balancing the rocket on a pole, dowel or pencil.
CG should be at least 1 rocket diameter higher than the CP!!

33. Center of Pressure (CP)
“2D” test to determine CP: a simple mechanical way to determine the approximate CP for the rocket.
Make a two dimensional tracing of the shape of the entire rocket on a piece of cardboard and cut out the shape.
Use a pole to determine where it balances.
The point at which the rocket is balanced is approximately the center of pressure.
It is extremely important the CP is closer to the tail than the CG.
If they are reversed or in the same place, the rocket will be unstable in flight

34. Adjustments and Size Ways to change CG and CP positions:
size of fins
location of masses (Putty could be added to the inside of the nose cone, etc.)
Total Rocket Length:
depends on mass and stability
Which depends upon design and materials
Research and Experiment with various designs and materials

35. Bottle Rockets in a Blizzard!
Have Snow Shovel, Will Launch!

36. Chasing Down a Rocket
Oh What Fun in the Ohio Snow!

37. Blue Skies are Deceptive!
Launching in Frigid, Single Digit Temperatures!

39. (Search: “water rocket” not “bottle rocket”)
Good Websites
(Search: “water rocket” not “bottle rocket”)
(Cool videos of extreme bottle rockets)
And many others!!
Good Luck…and Happy Launching!