Open Design Unreinforced Bottle General Design Parameters
- Rocket mass cannot exceed 1,500 grams. This is the total dry weight of all flying components in a flight ready condition including the pressure vessel, fins, nosecone, payload bay, camera, altimeter, flight computer, deployment system, batteries, and nozzle.(no reaction mass)
- Rocket can be of any design configuration included but not exclusive to (spliced bottle, single stage, multiple stage, drop away boosters)
- Water Rocket must use compressed ambient atmospheric air as its energy. Other gasses have much higher compression ratios and there needs to be a baseline so the record is fair to all. (see section II for special rules regarding bottled air).
- Rocket must carry onboard a mass produced recording ("Logging") altimeter to document the entire flight on a time vs. altitude graph to nonvolatile logging memory or telemetry to relay the altitude information to a remote logging receiver.
- Launch of each flight must be recorded by ground-based video.
- Entire flight including apogee must be photographed by an onboard video camera.
- Record altitude is calculated as the average of the two highest flights the rocket achieves within a 2-hour period.
(This criteria was inspired by high profile competitions such as the Ansari X-Prize.)
- The same rocket must be used for all averaged flights. The only portions of the rocket which can be replaced are expendable or consumable items. (batteries, tape, deployment chemicals, water, etc.). Items which are damaged in any record attempt must be repaired and rockets are disallowed from competing.
- If the rocket seperates during flight, all parts must have a recovery system to slow the descent to meet the maximun descent rate.
- Mechanical forms of propulsion are not allowed.
Bottled Air Rules
- Only bottled atmospheric air is allowed. No exotic gasses, cryogenics or combustibles.
- Tanks must be certified. (copies of tank certifications will be provided and filling station receipt).
- All local laws must be complied with for handling pressurized tanks as well as any certifications that the operator may need will also be provided upon a record submission.
- To prevent "stomp rockets" the rocket must remain pressurized to full launch pressure for a period of no less then ten (10) minutes. (The ground view camera will show both the tank and rocket on the launcher during this 10 minute period).
- Bottled air pressure source must be located at the minimum safe distance of 50 Feet (15 meters) from the launcher (this allows the bottle air pressure source to be safely controlled in the event of an emergency).
- All WRA2 Water Rocket Safety Rules must be followed.
- All launched parts of rocket which travel over 6 meters (20 feet) in altitude must have a recovery system which limits their descent rate at time of touchdown at ground level to a maximum velocity of 10 meters/second (33 feet per second) This includes all pieces which separate or are shed off in flight.
- Recovery system malfunctions for any part will disallow any record flights.
- Metal components including but not exclusive to items such as screws, nuts, bolts, rivets, pipe, sheet metal, steel, copper, and alumminum shall not be attached to any pressurized portions of the rocket.
Pressure Vessel Rules
- Pressure vessel and fuselage of rocket must be constructed from soft drink bottles or similar plastic containers.
- Pressure vessel and fuselage of rocket must be constructed from a single layer (overlaps due to splicing or joints permitted as long as the total overlap area of the pressure vessel does not exceed 30% of the total area of the pressure vessel).
- No forms of reinforcement are allowed.
- Plastic container can be modified in any way. (splicing, stretching, cutting, etc.).
- Composite materials are not allowed for the construction of the pressure vessel.
- Rocket must be transparent over at least 50% of its surface. (this will prevent forms of reinforcement from being hidden under paint)
- Pressure vessel and all external parts of the rocket may not be fabricated from metal. (see the WRA2 Water Rocket Safety Rules). Prohibited items include but not exclusive to are items such as screws, nuts, bolts, rivets, pipe, sheet metal, steel, copper, and alumminum.
Reaction Mass & Launcher Rules
- Rocket must be launched from a stationary position on a fixed launcher. (slingshots, trebuchets, catapults, cannons, and all other forms of launcher boost assist are forbidden). Launch tubes are allowed as long as the internal pressure of the rocket is the only supply of energy.
- Projectiles from Air Cannons are not acceptable.
- Reaction Mass must be primarily ordinary tap water.
- Thrust must come from expelling reaction mass, not from air discharge.
- Water reaction mass must fill a minimum of 20% of the volume of the Pressure vessel.
Filing a Record Claim
- Unedited onboard videos for both flights (Videos may be uploaded to Youtube).
- Mass of rocket (a photo of the rocket on scale with reading visible is also acceptable).
- Ground videos for both flights (Videos may be uploaded to Youtube).
- Detailed still photos of the finished rocket.
- Time and date for each flight.
- If using bottled air: copies of the tank and operator certifications.
- Detailed still photos or videos of the rocket being constructed (Videos may be uploaded to Youtube).
- Design drawings.
- Simulator data.
- Atmospheric data at time of launch (temperature, barometric pressure, and relative humidity).
- Launch Pressure.
All record claims must be filed to the WRA2 Contest Submissions for public review.
Maximum file size 45MB per file.
Questions & Answers
- If you have any questions about the rules or if your rocket is eligible for world record competition, please post them in the WRA2 Competition Q & A forum for a prompt answer. Remember that if you are in doubt, ask before you build.