KX1918 fire and water arrow set (middle)
KX1919Fire and water arrow set (large)
Kx1920-a water rocket set (full set)
Kx1920-b water rocket set (launcher inflator)
Kx1920-c water rocket set (launcher)
Kx1920-d water rocket set (inflator)
KX1920-KX805 threaded nozzle
KX1920-PJ8 rocket head large

KX1920-PJ9 rocket head medium

Water rocket made accessories to protect the head suitable for all sizes of coke bottles
Details:
Rocket head: specifications:
Large rocket head: 105*105*120mm for 1.25L and 1.5L coke bottles, Sprite bottles
Medium rocket head: 75*75**110mm Applicable to 450ML and 600ML coke bottles, Sprite bottles 
Small rocket head: 25*25*67mm for 2.05 diameter tubes

1. Streamline design to reduce flight resistance and enhance aesthetics;

2. Make the center of gravity of the water rocket move forward to maintain the balance and direction of flight without additional counterweight;

3. The water rocket falls from the high altitude to protect the body of the arrow to the greatest extent.

Usage: cover the bottle, cut off part according to the size of bottle if necessary

To reduce weight, use electrical tape for reinforcement.

About bottles: suitable for the mainstream carbonated soda bottles on the market, including: Pepsi cola (recommended), Coca Cola, Sprite, fanta, mirinda, 7up, etc., can not use mineral water bottles


Water rocket is a toy designed by mass ratio and air pressure. It is also one of the famous cases in physics teaching, which can cultivate students' interest in physics learning. The physics principle contained in it is an important basis for understanding mechanics in physics.
Water rocket is called air pressure type water jet rocket, water propulsion rocket. Is the use of discarded beverage bottles into the power cabin, arrow body, arrowhead, tail wing, parachute.

1 rocket overview
Water rocket is called air pressure type water jet rocket, water propulsion rocket. Is the use of discarded beverage bottles into the power cabin, arrow body, arrowhead, tail wing, parachute. Fill in a third of the water, use the pump to fill air to reach a certain pressure after the launch. Is the ratio of the use of air and water quality (771 times), the density of water is the air, compressed air from the water down the nozzle at the end of the rocket, the under reaction, rapid water rocket, acceleration and inertial gliding in the air, like a missile has a flight path, finally reaches a certain height, open the parachute model of rocket landed in the air.

Water rocket is teaching in fun, high content of science and technology, by the majority of teenagers love hands-on, brain science teaching materials. Students can have an intuitive understanding of the launch of missiles, launch vehicles, the process of recovery, the flight of missiles and aircraft flight principles and differences. Explain Newton's first, second, and third laws (inertia, conservation of energy, action and reaction) and learn some basic aerodynamics and flight mechanics. So that the majority of young people understand space science and technology, love space science and technology, for the national space industry training, training, transport excellent talents. (many competitions have been held across the country ~~)

2 emission principle

Use rubber - tight bottles to form an enclosed space. The gas is driven into the airtight container to increase the air pressure in the container. When the maximum degree of contact between the bottle stopper and the bottle stopper is exceeded, the bottle stopper and the bottle stopper will be free from each other, and the water inside the arrow will be ejected backward to obtain the reaction force. The biggest difference between a water rocket and a rocket is that the medium of its propulsion changes from hot air to water. Before launching the water rocket, air will be injected into the rocket to reach a certain pressure. Since the high pressure will naturally flow to the low pressure, when the nozzle is opened, air will flow to the nozzle naturally. However, because the water is blocked in front, water will be pushed out of the rocket by air, and the rocket will gain forward speed.

3 rocket making


Material preparation

2~6 2.25l coke bottles, scissors, single-sided blades, corks, ball needles, ball pen refills, stapler, double-sided tape, colorful decorative paper. Tablecloths and other lightweight and airtight materials

The production process

1. Production of pressurization plug: cut off the thick end of the rubber plug with a knife, the incision diameter is 2.3cm, install valve core, rubber tube and nut through the hole, and force the rubber plug into the bottle mouth, the part exposed outside the bottle mouth is not more than 2mm; Use scissors to cut a hole about 12mm in diameter in the middle of the cap so that only the valve core is visible when the cap is tightened.

2. The flank of the production: use a cardboard cut out four wings, in order to make the rocket flight had good stability qualitative, flank must have high hardness, if paper tablet hardness is not enough, can fold two or three pieces glued together, cut after good wing, will \"paste claw\" alternately back on both sides, with transparent tape symmetrically paste side at the bottom of the rocket.

3. Take out one of the coke bottles and cut it into three equal portions about one-third apart. As shown in figure 2, leave the mouth and middle part of the bottle and turn the second coke bottle upside down. As shown in figure 3, the top of the first bottle is placed at the bottom of the second coke bottle, and the middle part of the first bottle is placed at the top of the second coke bottle. Cover with double-sided adhesive. Take out another piece of cardboard and cut out 4 balance wings. Too big balance wings are too heavy and too small to balance.

4. Make parachute, fold a square tablecloth on the edge, then fold on the edge, take the center as the center, fold in half for 2 times, cut off the excess with scissors, make it into a circle, stick the line. 1 prepare materials. Three or four 2.5-liter jianlibao bottles or coke bottles, some X-ray films, no. 3 and no. 4 soft rubber plugs for several chemical equipment, a complete set of single-cycle valve core, a pair of scissors, a knife, transparent adhesive, double-sided adhesive and insulating adhesive cloth, and a 502 glue.

The second method: 1. Making wings. Use scissors to cut the X ray into 28 pieces of the same size right Angle trapezoid, trapezoid length 12cm, 6cm high, inclined waist and long bottom included Angle about 45 degrees. Cut another 4 trapezoids of the same specification but 8cm in height, with a short bottom connected to two overlapping surfaces (used as the surface of the wing). Use double-sided tape to tightly bond 7 small trapezoids into a thick trapezoid, making it straight and flat. Then use a large double-sided trapezoid to wrap it tightly and glue it tight. To flatten the thick surface of the wing, use scissors or a knife to flatten and straighten it. Then seal the thick surface of the wing with insulating glue. Finally, fold the outgrowth on either side of the wing outward at 90 degrees. Thus, the remaining x-rays are made into three machines as described above. 2. Fuselage production. Take a jianlibao bottle (the arc of the bottle head is more natural, which can be used as the rocket head to reduce air resistance) and cut it horizontally 11cm away from the lower end. Glue the part with the bottle mouth to the bottom of the other bottle, and wrap more loops in the connection with the insulation glue to make it firmly. 3. Air plug production. Take a no. 4 soft rubber plug, use the hole opening tool to open a flat hole slightly smaller than the valve core sleeve at the bottom center of the rubber plug, and then use a knife to cut away the thin end about 0.6cm. Place a larger \"ring\" on the valve sleeve (available in hardware stores), mount the valve from the thin end of the rubber plug, put on a \"ring\" of the same size, screw and tighten slightly. Finally, the gas plug will be ground into a cylinder with a grindstone, just enough to fully enter the mouth of the coke bottle or a little tight, with the valve core can be used. 4. Gun head production. Take a no. 3 rubber plug and use a knife to sharpen and round it. Assemble the wings. Take a jianlibao bottle and cut a cylinder with length slightly longer than the length of the wing. Use transparent glue and insulating glue to glue the four wings together. Finally, the cylinder attached to the wing is placed on the bottom of the water rocket so that it is level with the mouth of the bottle (this is not necessarily the best position, but can be determined by adjusting up and down in flight practice) and is wound tightly with insulating glue. 6. Other. In order to increase the contact surface between the air plug and the bottle mouth to increase the air pressure in the bottle, the large end of the air plug can be tapered with a knife to make it round, flat and rough. Because the fuselage grew a section to do the rocket head, the rocket head part is lighter unbalanced, can be properly stuffed into the paper to achieve balance. To minimize air resistance, apply 502 glue to the nozzle of the rocket head. According to the above method a simple water rocket can be made. According to the water rocket developed by us, it can fly about 160 meters horizontally and 40~50 meters vertically through practice improvement.

Water rocket launch method: 1. Water control. There is a certain proportion between water consumption of water rocket and air capacity space of the rocket, neither too much nor too little. The optimal water consumption is about 1/4 to 2/5 of the space of air capacity of the rocket (about 600 ml in the space of 2.5 liters, which can be searched and determined several times).

2. Launch Angle. Horizontal flight, due to the air resistance, the best Angle of launch between 50 and 55 degrees, different water rockets may be different, can be determined by the control variable method of test. The best Angle for our water rocket is about 53 degrees. The vertical direction is 90 degrees.

3. Use of air plug. The use principle of the air plug is to adjust the tightness degree of the air plug by compressing the volume expansion of the soft rubber plug. The more severe the compression, the larger the volume expansion, the tighter the air plug, and the larger the air pressure to push the air plug out, that is, the more power the rocket gets. The specific method of use is as follows: first remove the valve core of the gas plug, put the gas plug into the bottle mouth of the rocket in the original shape, then tighten the screw of the gas plug with sleeve (a kind of tool specially used for screwing, which is sold in hardware store), and finally install the valve core to add gas for use. (note: the tightening degree can be adjusted as needed.)

4. Launch stability control. Only horizontal launch is discussed. Need to make a launch pad, pad to equipped with navigation, navigation track not too long nor too short, generally for 60 cm long (available three teaching with the big triangle and two broomstick patchwork, to reduce the broomstick make navigation track friction of water rocket, usable cellophane tape paste broomstick or model as shown in the illustration). When the weather is calm, the target is being launched at the best launching Angle. In windy weather, it should be adjusted according to the wind and wind direction and the direction of the launch target to maintain the best launch Angle.

5. Notes. When launching, make sure that the rocket and the orbit are straight and consistent. If it deviates from 1 to 2 degrees, it will affect the smoothness of flight and it will fly in the shape of \"8\". When pumping with the pump, to as smooth as possible, pumping frequency should not be too slow should be faster. To make the gas plug as tight as possible, adjust by tightening the screw on the gas plug. The tighter the gas plug, the higher the air pressure in the bottle and the greater the power of the rocket. Take the first bottle and call it bottle A. Draw a line on the top and bottom of the bottle, 1-1, 2-2. 1-1: the curve on the selected bottle is close to the curve of the rocket foam head. 2-2: select about 0.5cm below the curve straightening point at the bottom of the bottle.

Cut (cut) with art knife (or scissors) from the top of line 1-1 and about 0.5cm below line 2-2.

Use scissors to clip slowly to draw line place, make its level off as far as possible, so that when joining with B bottle, can close more closely. Put the rocket foam head on the top of bottle a. check whether the foam head is in the center of the approved bottle. If already put, use electrical adhesive tape to wrap at contact place, try to fix. Take another bottle and call it bottle B. Remove the cap and tighten the nozzle through the opening of the bottle. Connect bottles A and B. Then as for the flat table or ground rolling, see if the connection flat, rolling smooth. If, try to fix with electrical adhesive tape. Take the third bottle, and call it bottle C. Draw a line in each of the 3-3 and 4-4 bottles. 3-3: select the top of the bottle about 0.5cm below the turning point of the curve. 4-4: select the bottom of the bottle about 0.5cm below the turning point of the curve. Cut (cut) with art knife (scissors) from the top of line 3-3 and about 0.5cm below line 4-4. Fold the cardboard in half and draw the four trapezoids in pencil. Then cut along the edges of the scissors. Note: the size and shape of the tail can be varied to test its impact on flight. Again, slide to a trapezoid of the same size as the thick board. Cover the finished slides on the outside of the cardboard trapezoid. You can use double-sided tape to join the slides and the cardboard together. Use double-sided tape at the bottom of the folded section. This step is to make the four tail fins to stick on the C bottle. Four tail fins complete the diagram. Put the four tail fins on the C bottle, and make sure that they are cross symmetrical, so that they can be balanced. First with electrical adhesive tape paste on both sides of the tail, adhesive must pay attention to the length of electrical adhesive tape must be long enough, the top need to be higher than the tail about a tape height, the lower part of the back into the C bottle, in order to increase the degree of firmness. Then electrical tape around the tail wing upper about two turns. Connect bottle C and bottle B with electrical tape. Note: it is also necessary to keep the body of the water rocket straight to ensure the correct direction of flight.

Make key

In the production process, the nozzle is the most important, the seal must be good, otherwise it will not provide good pressure. Air needle in the cork, also to achieve the tight water, it is best to use a red-hot tip through the hole. If there is still water leakage, you can add a ball pen refill on the air needle, the top of the ball pen refill sticking out of the water, can prevent bubble tumbling and leakage when pumping. The cord of the parachute must be glued down, or the pressure may cause the cord to fall off the parachute. [1]

4 world record

The height is 830 meters and was created by several students at the university of Cape Town. The rocket has a strange shape and looks like a chopstick from a distance. It is designed by the professional team after several data collection, analysis and calculation, and made of special materials. And the traditional water rocket production process and concept are greatly different.

5 research methods

The relationship between the vertical elevation of the water rocket and the water level in the bottle

The relationship between the vertical elevation of the water rocket and the water level in the bottle can be obtained through experiments: the experiment shows that the water rocket flies the highest when the water volume is 1/3. The result shows that the air pressure is proportional to the range. This is because the greater the pressure, the greater the force of the water jet, the greater the impulse of the water rocket, the water rocket do recoil. However, when the launching water was more than 1000ml, the water in the water rocket was not sprayed out completely. Due to the decrease of air pressure, it stopped accelerating, increased the weight of the water rocket, and made the water rocket fall down in advance under the influence of gravity. The greater the mass, the greater the momentum that needs to be provided. When the mass is constant, the greater the velocity, the greater the momentum. The way to increase the speed is to increase the amount of water spraying per unit time. Therefore, only when the air pressure and water volume inside the water rocket are appropriate, can the enclave be further and higher. In the experiment, it was found that if the amount of water was larger than the upper limit of the amount of water that could be injected at a fixed pressure, the water in the water rocket would not be sprayed out. How to avoid the situation that the water would not be sprayed out? According to PV=nRT, the upper limit of the amount of water ejected at a certain pressure can be calculated. If the amount of water is not enough to a certain pressure of the water can be sprayed out earlier. According to the theory, when launching, we first measure the maximum value of the water-filled rocket, and then calculate the maximum amount of water that can be ejected at this pressure. According to these two data, the maximum range of the water-filled rocket can be reached (Pmax=Fmax×Mmax).

How to improve the stability of water rocket

In the process of rising, the water rocket does not rise vertically, but often rises horizontally or sideways. And that means we have to make it more stable, we have to make it go straight up. To improve its stability, the effect of atmospheric resistance must be considered. First, the top of the water rocket should be pointed to reduce the air resistance. Secondly, the shape of the cylinder should be close to streamline, so as to facilitate the passage of airflow. To get it up straight, and to get it up straight when we put it up, we took a tripod and held the water rocket up (not tight) so that it could stand upright.

Impact of launch orbit on range

Fixed water amount: 600ml, launch elevation Angle: 50°. Launch water rockets with trackless launcher and 70cm launcher respectively and record the results and launch situation. Compare the impact of launch orbit on flight distance. The experimental results show that the range caused by the same impulse of both the orbital and trackless launchers is about the same, so the range is not affected by the presence or absence of orbit. However, when the impulse is smaller, the water rocket launched by the trackless launcher tends to deviate from the predetermined direction. Because the launcher has two fulcrum, the water jet is not easy to produce other direction of the component force, so the water rocket can accurately straight forward. Therefore, an orbital launcher is more accurate than an trackless launcher.

Impact of warhead weight on launch trajectory

Fixed water amount of 600ml, launching elevation Angle of 50°, using an orbital launcher. The warhead is placed in sequence with the filler, with a mass of 30g, 40g, 50g, 60g. Compare the impact of warhead weight on launch trajectory of water rocket.

It is known from the experiment that the warhead without the front filler is significantly tilted backward due to the influence of the tail mass. At this time, since the center of the object rotation is the center of gravity, we can take the center of gravity G as the fulcrum, and in the case of only gravity, the warhead becomes a horizontal lever with G as the fulcrum. During flight, warhead A and projectile tail B will be affected by the same wind resistance, but due to different moment arms. AB), so the moment generated at point A is greater than that at point B, so the water rocket will rotate and affect the channel. So we have to put the front filler, move the center of gravity G toward A, make the arm AG=BG (the midpoint of the water rocket), so that A and B produce the same torque and balance. But if the front fill is placed too much, the center of gravity is pushed forward, causing a moment arm AG

The effect of launching elevation Angle

Fixed amount of 500ml water, front filling, using rail emitter. Launch elevation angles of 35°, 45°, 55°, 65° and 75° were used respectively. The effect of elevation Angle on launch distance of water rocket was compared.

The slant launch of the water rocket is related to the slant launch, so it can be theoretically obtained that when the elevation Angle of the launch is 45°, the flight distance is the longest. However, it is known from the launch results that the maximum range can be achieved when the launch elevation is between 45° and 55° (about 52°). When the launch elevation Angle is too small, the water rocket upward component force is not big, making the climbing height is not big, and because the weight of the water rocket is pulled by the gravity of the earth, it is easy to fall, resulting in a shortened range. When the Angle is too large, its upward component is large, but the forward component is too small, so that the range is too short, line into \"shot high, but not far\" situation. Therefore, in the aspect of launching Angle of water rocket, it is necessary to consider the moderate upward force and forward force, the influence of various external factors and the launching elevation Angle.

6 technical interest points

There are many types of water rocket, including single stage single push (one stage rocket, one propeller nozzle), single stage multiple push (one stage rocket, multiple propeller nozzle) and multistage multiple push (multistage rocket, multiple propeller nozzle), few multistage single push. Because single-stage multi-push is usually a \"passive separation\" of the propeller (one or several bottles in series) and the arrow body and the propeller are launched simultaneously, it is generally not considered as a multistage water rocket although it has the effect of thruster ejection. The multi-stage water rocket adopts the technology of \"active separation\" between the thruster and the body of the arrow, and is the body of the thruster. The technical interest of water rocket production mainly includes: nozzle technology, active separation technology and recovery technology.

The method of making bottle stopper with bicycle inner tube and air port is more popular in China, but this method can't control the launching time well, so it can't realize multi-push perfectly. Pulleys and wires were used to pull down the launcher sleeve ring to achieve good control of launch time.

Generally speaking, single-stage multi-thrust water rocket involves the thrust difference between the propeller and the body of the arrow. Due to the natural \"passive separation\" by gravity, the thrust of the propeller must be greater than that of the arrow body, so as to ensure the maximum thrust and maximum integration of the two when the water rocket is launched. When the thrust of the propeller is exhausted, it will fall off naturally due to the action of gravity. The main body continues to fly. The advantage of the rocket is that it does not involve complex multistage separation techniques, has a lot of thrust and is relatively simple to make. It is important to note that the diameter of the nozzle is smaller than the diameter of the propeller nozzle to achieve thrust difference. The body of an arrow usually USES parachute recovery technology.

Let's talk about the multistage multistage water rocket. The water rocket is huge and can reach a height of more than 200 meters. The highest known launch height was 864 feet, or 263 meters, created by foreign water rocket enthusiasts on October 30, 2010. Although the launch height of the rocket is not very high, it is more challenging and favored by water rocket enthusiasts because of the \"staggered ejection\" technology, \"active separation\" technology and the \"graded recovery\" technology of the body and propeller. Foreign active separation technology has different styles, but the basic principle is the same. The first and second stage active separation can be realized quickly by utilizing the gravity of the propeller when the thrust is exhausted and the spring force in the embedded separator as well as the jet thrust of the second stage arrow body at the beginning of separation. The thruster section enters the falling phase and opens the parachute, while the second stage continues to rise until the thrust is exhausted and the second stage opens the parachute. If there is a third level, advance in turn.

Single-stage water rocket and multistage water rocket can do a lot, but the difference between the two is not difficult to distinguish from the appearance can be resolved. The single-stage multistage rocket (a dummy stage) has the body of the rocket and the nozzle of the propeller on the same plane, because this is the easiest way to launch simultaneously. A multistage multistage water rocket is not. Its second stage nozzle must be connected to the propeller, because the second stage is not working at the beginning of the launch. So just look at the position of the nozzle.

7 extension production

1. After getting familiar with the basic production of water rocket, you can try to make large and multi-stage water rocket. Choose the lighter weight of the metal, provide air pressure by the air pump to complete.

2. Production of multi-stage rocket:

Several water rockets are tied together and air pressure is provided by an air inlet. At the same time ejecting the water column, enhances the water rocket flight ability.

After more than half a semester of exploration, research, experiment we initially completed the water rocket development work, from which we have improved in many aspects. Through the method of searching information, we have a very deep understanding of the development history of rockets, especially the development history of rocket technology in China. We know that rockets are a necessary means of delivery for modern space flight. China is the birthplace of rocket technology. However, due to the shortage of funds and technical defects, the space industry is developing slowly.

2. Divide one of the bottles into three parts; Leave the mouth and middle of the bottle

3. Cover the remaining bottle mouth and middle part with the bottom and mouth of another bottle respectively, apply adhesive and fix with insulating tape

Ps: the rocket must be kept in a straight line

4. Use thick transparent film or pearl version to make four tail fins and fix them in the fire evenly
The second half of the water rocket ps: apply adhesive and secure with tape. Unevenly distributed or unfixed will affect the direction of the rocket

5, set fire arrow and nozzle, ready to fly

6. Prepare for launch from the launch pad