How do you make a bottle rocket stay in the air as long as possible?

Answer 1

To have a water rocket stay in the air for a longer time make your nozzle smaller. It will allow the presurized water to escape more slowly. But do not make your nozzle to small always there will be to much drag on the rocket and not enough thrust to propel it upwards. To stabilize your rocket use fins that are down on the bottles neck, this will make your rocket more stabil in flight. Just like the feathers on the back of an arrow. I hope i helped answer your question.

Answer 2

A 2-Liter plastic soda bottle makes an excellent motor for a simple water rocket. With practice, you can make a really fine water rocket using 3 2-liter bottles, cardboard, card stock, tape, and readily available materials found in most homes. You may need a visit to the hardware store to make the required launcher, or there are commercially available launchers.

The biggest challenge for making a rocket with a soda bottle is achieving stable flight. This is because of the large diameter of the bottle relative to its length. It is possible to make the rocket body longer, and thus more stable, by adding a second bottle as a body, and a nosecone made of card stock. Parachute recovery can also be implemented using a simple Nose Separates at Apogee system.

See: http://www.water-rockets.com/article.pl?101

See also: http://www.YouTube.com/watch?v=tPN03Na2boo

Answer 3

1. Use higher pressures. As long as the rocket's pressure chamber remains within safe limits, increasing the pressure can have a significant impact on altitude gain. It may be possible to reinforce the rocket to hold higher pressures without adding too much extra weight.

2. Keep weight to a minimum. Every rocket has an optimal weight. Small and simple single bottle rockets may sometimes be under their optimal weight, and adding a little weight to the rocket may increase altitude. Due to construction techniques, larger rockets typically come in above their optimum weight and as a result need to be built as light as possible. Use a simulator to calculate the optimum weight for a particular rocket. Also keep any payload weight to a minimum.

3. Increase rocket volume. Generally increasing a rocket volume will also increase altitude. The best way to increase the volume is to make the pressure chamber longer. This doesn't increase drag significantly, although there is a corresponding weight penalty. Increasing the diameter of a rocket to increase the volume will not only result in more weight, but more drag, and generally lower the maximum pressure the pressure vessel can hold.

4. Streamline the body of the rocket to reduce drag. Avoid any unnecessary protrusions into the air stream. Keep the body of the rocket as smooth as possible, avoiding sharp transitions. The ideal shape is an elongated teardrop. Depending on the construction materials available, a minimal diameter rocket can reduce drag significantly, at the cost of volume. A smaller diameter rocket can also hold higher maximum pressure.

5. Use a launch tube on the launcher. A launch tube can have a significant effect on the apogee of a rocket. The longer the launch tube the better. The diameter of the launch tube should be as big as possible and should be about the size of the nozzle to reduce the amount of water loss as the rocket accelerates up the tube. Note that a maximum sized nozzle may not be the most optimum size after the rocket leaves the launch tube. Consider using a T-nozzle for better efficiency.

6. Use the right amount of water. While a third the volume may be a good approximation, every particular rocket will have an optimal water fill based on its weight, drag coefficient, pressure, nozzle size etc. Use a simulator to predict the best amount of water to use for each rocket configuration.

7. Use an optimum sized nozzle. The nozzle diameter should be optimized based on the various rocket parameters. Use asimulator to figure out the optimal nozzle size. There may be limitations on changing the nozzle size due to the type of launcher and launch tube used.

8. Use multiple stages. Correctly designed multi-staged rockets can increase the altitude of the sustainer over single stage designs. Consider your highly optimized rocket sitting on top of a booster.

9. Optimize stage release timing. Releasing the next stage of a multi-stage rocket is critical in maximizing the altitude reached. Use of real-time in-flight measured flight parameters for initiating staging can achieve best results. The best time to release the next stage is just after booster burn out just as the booster starts slowing down.

10. Use a boat-tail on the rocket. A smooth transition from the rocket body diameter down to the nozzle will assist with base dragreduction.

11. Allow the air to cool inside the pressure chamber. As air is compressed inside the rocket it is heated. As the air cools, the pressure will drop in proportion to the temperature decrease. You can trickle fill the rocket before launch to make sure the optimal pressure is achieved.

12. Streamline the leading and trailing edges of your fins. To reduce the profile drag of your fins they should have an aerofoil profile. See this document for more details.

13. Use 3 fins instead of 4 or more. If the launcher allows it, and the rocket is otherwise designed to be stable, the use of less fins should result in less drag and less weight on the rocket.

14. Use optimally shaped fins. The fins should have an optimal shape. See this document for more details. The optimal shape will vary based on the rocket design and the rockets flight profile.

15. Use optimally sized fins. While having the correct fin profile and shape is important, it is also important to not make the fins too large. Fins that are larger than what they need to be add to the drag and weight of the rocket. Large fins may also cause the rocket to be over-stable.

16. Ensure smooth internal water flow through the nozzle. Increase nozzle efficiency by ensuring non-turbulent flow of water and air from the pressure chamber and through the nozzle. There should be no sharp transitions in the flow. Polish the inside of the nozzle.

17. Fly on a windless day. Wind will cause the rocket to weather-cock into the wind causing it to fly in an arc and achieving a lower altitude than if it went straight up. The amount of weather-cocking will depend on the rocket's stability design and the wind speed. A rocket that is over-stable will tend to weather-cock more.

18. Use a rounded nosecone. Parabolic nosecones are the most efficient for water rockets as they travel well in the subsonic range. Here is a nosecone shape comparison documentdetailing common nosecones used by model rockets.

19. Use a less dense liquid. Lower density liquid can have a positive effect on raising the apogee of the rocket. However, using a liquid other than water may mean that the rocket may not be considered a water rocket. Changing the density of water can be achieved by aerating the water such as in a foam. Use a simulator to predict the altitude of a rocket with a lower density liquid.

20. Use a heavier gas. Some gasses like CO2 can provide better performance due to their heavier molecular weight and hence provide a greater reactive mass.

21. Align the fins properly. Misaligned fins can cause more drag and potentially excessive rotation of the rocket. The rocket looses energy due to drag and some of the energy goes into the rotation of the rocket. Fins should also be as rigid as possible to prevent fins fluttering.

22. Make the rocket stable. An unstable rocket will not fly straight and achieve a lower altitude. Rockets should be designed to bestable when they are dry. The boost phase is generally very short with larger nozzles and so the rocket spends most of its ascent dry. When using smaller nozzles, the rocket should be designed to be slightly more stable to account for the longer duration of the water being in the tail of the rocket.

23. Remove internal obstructions. Streamlining the internal water and air flow adds to the efficiency of the rocket. If the construction techniques allow, consider removing flow constrictions such as couplings/baffles to insure most efficient flow and prevent water being retained during the thrust phase.

24. Fly from higher elevation launch sites. Starting at a higher altitude means the air is less dense and therefore the rocket will experience less drag. For example on average the air in Denver, Colorado is ~15% less dense than at sea level. See here forelevation vs air density graphs.

25. Launch rockets into thermals. Flying a rocket in a thermal can add extra tail wind to the rocket reducing drag. Here is anextensive document on thermals, how they work and how to find them. Thermals are also useful for increasing the air time of your rocket.

26. Point the launcher as vertically as possible. All things being equal, a rocket that flies 2 degrees away from vertical will fly about 0.5% lower, and a rocket that flies 5 degrees away from vertical will fly about 2-3% lower.

27. Optimize direction of second stage after staging. Ensuring the next stage of a multi-stage rocket leaves as close to vertical as possible can be tricky, but is essential in reaching maximum altitude.

28. Launch rockets on a humid day. Humid air is less dense than dry air. Lower density air will lower the drag on the rocket. At standard temperature and pressure at sea level, 100% humid air is approximately ~1% less dense than dry air. See the air density calculators for more information.

29. Launch rockets on a hot day. Higher air temperature means lower density. Here is a document relating air pressure, air density and temperature. See the air density calculators for more information.

30. Grease the launch tube for less friction. If you are using a launch tube with your launcher that has a relatively tight fit on the nozzle, make sure friction is reduced by lightly lubricating the launch tube. Less friction will result in higher take-off velocity.

Answer 4

Water rockets uses the water as a fuel for take off. The water is the thing that made it fly as friction opposes the water and the air, hence , the water rocket will fly. The distance the rocket travelled is affected by how it was made, amount of water, and how well it was made.

Answer 5

Make the rocket bigger and increase its fuel supply, heat the front of the craft (front top for airplanes).

You can also add heat wich will allow rockets, planes and boats to travel faster with taking safety precautions of not heating up the fueltank (front of craft), this will reduce drag caused forward airpressure/waterpressure.

A better way of exprimenting and safer would be using water rocket or inertia rocket and always in a secluded non tree/grass area. (preferably large desert area)

This is also why meteors are some of the fastest objects on the planet due to the fact they heat up, the heat reduces drag caused by airpressure. As an object increases speed, the amount of air hitting the front increases, "slowing it down" just like blowing on an object to move it. this is why when you increase an airplanes size, you have to increase its speed, it needs more momentum to increase the amount of air hitting the bottom wich creats lift. Stop using a heat shield and give rockets what they want, that's what makes objects travel faster. (heat the top for rockets), (front stern for boats and front and top for airplanes).

Its also why mammals have nostrils and why your bodys air supply heats up, to reduce the effects of drag created by airpressure and waterpressure for seacreatures.

hot air generates lift because it is less dense than colder air (gets any colder air becomes h20).

Answer 6

Fuel inside the rocket is converted into kinetic energy that is known as thrust. The thrust pushes the air under the rocket downward which means the rocket must go up according to Newton's laws of physics.

Answer 7

add more mentos!