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A water rocket is a type of model rocket using water as its reaction mass. The pressure vessel (the engine of the rocket) is constructed from thin plastic or other non metallic materials (usually a used plastic soft drink bottle) weighing 1,500 grams or less. The water is forced out by compressed air. It is an example of Newton's third law of motion.


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Class B clarification

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SaskAlex
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Class B clarification

Post by SaskAlex » Sat Feb 06, 2010 12:22 pm

High, I was just wondering whether there was a strict distinction between a two-stage rocket and a rocket with drop away boosters, in terms of eligibility for class B. I have a rocket in mind I might try to build this summer. In almost all respects, it's like any other two-stage rocket: sustainer goes on top of booster, booster volume much greater than sustainer, and there is no launch tube for the sustainer. However, it's a cluster booster and the sustainer will actually be firing right from launch.

So is it eligible? And just out of curiosity, if it is, would rockets like those of Air Command also be eligible?



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Re: Class B clarification

Post by WRA2 » Sat Feb 06, 2010 6:33 pm

SaskAlex wrote:High, I was just wondering whether there was a strict distinction between a two-stage rocket and a rocket with drop away boosters, in terms of eligibility for class B. I have a rocket in mind I might try to build this summer. In almost all respects, it's like any other two-stage rocket: sustainer goes on top of booster, booster volume much greater than sustainer, and there is no launch tube for the sustainer. However, it's a cluster booster and the sustainer will actually be firing right from launch.
Any rocket with "drop away" boosters would be considered "multi stage" and would be eligible to compete in the "Class B" competitions. It does not matter if the engines are all fired ar once or in series. Now if you constructed the same rocket and had the "boosters" permenently attached then it would be considered a single stage. The difference is that to be considered multiple stage the rocket sheds "engines" during the flight thus reducing weight and drag.
SaskAlex wrote:So is it eligible? And just out of curiosity, if it is, would rockets like those of Air Command also be eligible?
Rockets using the method of parallel boosters similar to the rockets built by Air command are eligible for the class B competitions. Just be careful about the weight as the total dry weight of the entire rocket (including boosters, staging mechanism, payload, recovery system, and any structural components to keep boosters in alignment). Meeting the weight requirement will be the most challenging part.

Good luck.


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SaskAlex
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Re: Class B clarification

Post by SaskAlex » Sat Feb 06, 2010 6:55 pm

Thanks, that what I thought. I just wanted to make sure before I started, because it's going to be a lot of work. I'm thinking fairly small compared to most people's two stage rockets, so I shouldn't have too much trouble staying under 1500 grams.



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U.S. Water Rockets1
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Re: Class B clarification

Post by U.S. Water Rockets1 » Sat Feb 06, 2010 11:19 pm

If your rocket exceeds 1500 grams in weight, most countries consider it to be in the "high power" class, and you won't be able to launch it without special licensing and permits and there's usually rules about informing air traffic control and proper authorities of your launch. You may be breaking the law if you launch a water rocket that is too heavy. It's not worth risking getting arrested over.


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RaZias
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Re: Class B clarification

Post by RaZias » Sun Feb 07, 2010 4:20 am

U.S. Water Rockets1 wrote:If your rocket exceeds 1500 grams in weight, most countries consider it to be in the "high power" class, and you won't be able to launch it without special licensing and permits and there's usually rules about informing air traffic control and proper authorities of your launch. You may be breaking the law if you launch a water rocket that is too heavy. It's not worth risking getting arrested over.
Unfortenatly that depends of the country you are, I still belive that some countries don´t give a damn about the weight of the rocket (unless you are launching giant 50-100L barrels because someone will tell the cops that there is a crazy person trowing heavy stuff that can break a roof).

If I launch a 3Kg rocket here in Portugal nobody will complaint, unless the rocket looks massive in size because it will look dangerous to eyes of the people.

So before launching anything try to talk with a rocket association to know the laws, it doesn´t hurt to follow the laws.

I going to start to make WR in the beaches without no one near by but I am afraid from what a policeman can say so I am going to check it out.

Making WR near those guys addicted to kitting will be cool to call more persons to WR.


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SaskAlex
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Re: Class B clarification

Post by SaskAlex » Sun Feb 07, 2010 1:10 pm

That's funny Razias. I'm actually a bit of a kiter myself. But I think the two hobbies generally have very different people participating in them. It might not be the easiest group to recruit from.



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Re: Class B clarification

Post by Spaceman Spiff » Mon Feb 08, 2010 1:44 pm

From what people have said over the years, 1500g seems to be where all the countries with restrictive regulations draw the line. That's not saying that you can't do whatever you want for your own experiments, but in the competitions we all have to work under the same limitations.

The Olympics has prohibited the fancy low-drag swimsuits for their races, but nothing says you can't practice with them on. It would probably just make it more difficult to win without one.


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Re: Class B clarification

Post by WRA2 » Mon Feb 08, 2010 5:30 pm

Spaceman Spiff wrote:From what people have said over the years, 1500g seems to be where all the countries with restrictive regulations draw the line. That's not saying that you can't do whatever you want for your own experiments, but in the competitions we all have to work under the same limitations.

The Olympics has prohibited the fancy low-drag swimsuits for their races, but nothing says you can't practice with them on. It would probably just make it more difficult to win without one.
Spaceman is correct, We had to draw the line where the most participants would be able to comply.
Another reason is safety. Not everyone can launch in the middle of the desert or has the desire to launch at pyro meets. A heavy mass falling from the sky could injure or even kill. The beauty of the WRA2 is anyone has a chance to set a world record while launching from their own backyard. :WRA2:


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Re: Class B clarification

Post by U.S. Water Rockets1 » Sat Feb 13, 2010 11:02 pm

The weight limit has the added benefit of keeping the sport affordable! Everyone might think that a higher weight limit would make the rocket less expensive because they could use heavier materials that cost less. But in reality you're going to have big budget teams which will build their rocket right up to the max weight using the lighter and more expensive materials. 1500g of carbon fiber costs less than a higher weight of carbon fiber... so the price is limited by the weight limit. If there was no limit at all, then you'd have water rockets of virtually unlimited cost.


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