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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.

Airborn WRC

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Airborn WRC

Post by Water Rocket Expert » Tue Mar 18, 2014 3:28 pm

Hello

I have been going over the rules for different competitions and I had a question. For the WRC (Water Rocket Car) does the car have to touch the ground at all times. What would be the outcome if USWR put tiny little cardboard wheels on the X-12 and launched it horizontally. I didn't see a rule against that so is that a problem or does it have to touch the ground.


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Re: Airborn WRC

Post by WRA2 » Tue Mar 18, 2014 5:45 pm

Water Rocket Expert wrote:Hello

I have been going over the rules for different competitions and I had a question. For the WRC (Water Rocket Car) does the car have to touch the ground at all times. What would be the outcome if USWR put tiny little cardboard wheels on the X-12 and launched it horizontally. I didn't see a rule against that so is that a problem or does it have to touch the ground.
The term "water rocket car" means it has to roll on the ground. If it leaves the ground it would be classified as a rocket or plane.


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Re: Airborn WRC

Post by Water Rocket Expert » Tue Mar 18, 2014 9:09 pm

Some cars "bump" along the ground because of the rough surface. Is there a limit about how big those bumps can be?


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Re: Airborn WRC

Post by Water Rocket Expert » Tue Mar 18, 2014 9:20 pm

What if the car goes so fast it's bumps are like 100 feet?


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Re: Airborn WRC

Post by WRA2 » Tue Mar 18, 2014 10:05 pm

Water Rocket Expert wrote:Some cars "bump" along the ground because of the rough surface. Is there a limit about how big those bumps can be?
Skipping along over a rough surface would not be allowed and would disqualify the attempt. A rough surface would be a poor choice for a track to attempt a record on.


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Re: Airborn WRC

Post by bugwubber » Wed Mar 19, 2014 1:48 am

It would be wicked hard to get a horizontal water rocket car to leave the ground without a large wing. Even x12 would noseplant without wings. The current speed record is 150ft in just over 5 seconds. I think 30ft/sec works out to around 20mph.

If you leave the ground from a bump, you are pretty much guaranteed it is not going to come down right side up AND still heading in a straight line.

You also don't get as hard a kick that you get from vertical rockets because the air and water tend to mix as the come out.

The pyro guys that I've seen run their lightweight cars on guide wires for safety because if they didn't those cars would bounce all over the countryside. And set it on fire of course.

Just my 2 cents.

Oh and, try it- the sleds have been a lot of fun!


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Re: Airborn WRC

Post by Water Rocket Expert » Wed Mar 19, 2014 10:53 am

The rough surface would be as-fault. I like the sled idea. The only reason I asked was because I remembered several years ago in science class we made balloon powered cars. Anything as long as the balloon powered it and it had to have at least three wheels. Somebody made a plane and used the balloon as the rubber band. He won. Somebody else drew wheels on the side of a balloon with fins and the "car" never touched the ground except for liftoff. The cars fit the rules and were accepted because the rule maker hadn't put anything that restricted them in the rules.

Consider editing the rules to clarify on this. Most motor bikes leave the the ground on ramps and things and so does my dads Traxxas when it reaches about 50 mph.


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Re: Airborn WRC

Post by Water Rocket Expert » Wed Mar 19, 2014 11:01 am

Oh and actually you do get as hard of kick if when you make a splice you make a plastic sheet inside so the water is above the nozzle level. I have tried it and it worked exceptionally well.


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Re: Airborn WRC

Post by U.S. Water Rockets1 » Sat Mar 22, 2014 10:22 pm

Water Rocket Expert wrote:Oh and actually you do get as hard of kick if when you make a splice you make a plastic sheet inside so the water is above the nozzle level. I have tried it and it worked exceptionally well.
Do you mean some kind of baffle that keeps the water out of the nozzle?


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Re: Airborn WRC

Post by Water Rocket Expert » Sun Mar 23, 2014 12:24 am

I is just a cross section of the bottle so water is forced out the bottle. It pretty much just makes the bottom of the water be at or above the nozzle.


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