Water Rocket Flight Duration Competition General Design Parameters
- Pressure vessel must be fabricated from a single unmodified 2 liter or less (labeled capacity) soft drink container. (a photo of the bottle with label will be included with your submission photos) The only modifications permitted are to change the nozzle size or to attach fins, payload section to the external surface of the bottle. The label can be removed after the bottle is photographed.
- Rocket must use Water as its primary reaction mass.
- Water Rocket must reach altitude using a single stage
- Water Rocket must use compressed ambient atmospheric air as its energy. All Pressurization must be done at the launch pad via a manual pump. No compressors, combustibles, or bottled gasses are allowed.
- 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.
- Rocket must be completely scratch-built using materials which are not manufactured for model rocket parts. (with the exception of the Camera) Raiding hobby shops for nosecones, or fins, or any other pre-manufactured items is prohibited.
- Flight must be recorded by ground-based video to validate flight duration and recovery.
- Entire flight including apogee must be photographed by an onboard video camera.
- Buildings, trees or other objects will be considered "ground" when landing.
- Record is calculated as the average of the two longest duration flights the rocket achieves within a 2-hour period. Duration determined from the video taken by the onboard camera by timing the flights from launch pad to ground. Results must be repeatable!
- 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..) The same rocket must be used for all attempts. Items which are damaged in any record attempt must be repaired and rockets are disallowed from competing.
This criteria was inspired by high profile competitions such as the Ansari X-Prize.
- 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. Fast falling rockets, boosters, debris, or rocket parts can be very dangerous. Recovery system malfunctions for any part will disallow any record flights.
Pressure Vessel Rules
- 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).
- Pressure vessel must be entirely fabricated by the rocket builder.
- Pressure Vessel and all external parts of the rocket may not be fabricated from metal (see the WRA2 water rocket safety rules).
Reaction Mass & Launcher Rules
- Reaction Mass must be primarily ordinary tap water.
- Thrust must come from expelling reaction mass, not from air discharge. That would be considered an Air Cannon projectile.
- Water Reaction Mass must fill a minimum of 20% of the volume of the Pressure Vessel. Token amounts of water added in an attempt to qualify an air cannon projectile as a water rocket are not allowed.
Filing a Record Claim
- Ground videos for both flights. (Videos may be uploaded to Youtube)
- Detailed still photos of the bottle used to construct the rocket (with original label visible).
- Detailed still photos of the finished rocket.
- Time and date for each flight.
- Mass of rocket (a photo of the rocket on scale with reading visible is also acceptable).
- 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.