WRA2 Class A rules Q & A

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tsumrall
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Post by tsumrall »

There are non-metallic materials that are a lot stronger than aluminum... or steel for that matter. And we don't even own a lathe! There is no metal used in the construction of the pressure vessel used in the record flights.
Excellent.
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Post by rockets42 »

(sorry I posted this question earlier in the wrong thread, but could not delete it)

There is no mention of legal requirements within the class A rules.

Is a water rocket flight that does not meet the FAA rules still eligible to be considered for the class A competition?
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Post by Drag_Racer408a »

I don't think that your rockets will have a problem with the FAA. I found thisd on there site.
It is air traffic policy that all rocket launch vehicle proposals that seek a waiver of part 101 requirements, and that are expected to reach an altitude higher than 25,000 feet above ground level.
But i remeber that USWR said once that they always call there local airport since they are located right near it to make sure that there aren't any low flying planes going over there launch site.
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Post by rockets42 »

b. Other unmanned rockets. Those rockets or missiles that use more than 125 grams of propellant, or weigh more than 1,500 grams, including the propellant, must comply with all the requirements of part 101, Subpart C - Unmanned Rockets, and may require a license (or exemption) to operate under part 400 depending on other rocket characteristics.
The problem we have that although our rocket is under 1500grams dry with the water (propellant) it puts it over the 1500gram limit according to the regulations and is classified as an Amateur rocket.

Here is a succinct version of the rules, although you should verify with the actual ones on the FAA site. (I checked, they are the same)

http://www.seanet.com/~ssstolt/regs/faaregs.htm

Actually, it is not the altitude that is a concern, it is all the other conditions such as 1500feet clearance of any structures or people not associated with the launch, and the notification that has to be given to the FAA no more than 48 hours before and no less than 24 hours before the event, cloud cover conditions etc.

Our rocket may fit within the competition rules, but it may still be flown illegally, and that's why I asked whether its okay to fly in the competion illegally?
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Post by Tim Chen »

I don't think it would be wise to do anything illegal. It sounds like they did their homework and built their rockets so they would not exceed to hobby class and that would make it much easier to be legal.
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Post by dleatham »

can you tell me if you allow the using of ARB bottles on the launcher for this contest? i have trialed this idea and think it would be a helpful mod for my launch-pad design.
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Post by The Mooseheads »

dleatham wrote:can you tell me if you allow the using of ARB bottles on the launcher for this contest? i have trialed this idea and think it would be a helpful mod for my launch-pad design.
I guess that might depend on what the definition of an ARB Bottle is. Can you describe them in a little more detail?

Thanks.
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Post by dleatham »

The Mooseheads wrote:
dleatham wrote:can you tell me if you allow the using of ARB bottles on the launcher for this contest? i have trialed this idea and think it would be a helpful mod for my launch-pad design.
I guess that might depend on what the definition of an ARB Bottle is. Can you describe them in a little more detail?

Thanks.
we call them air reservoir boosters. they help to make the rocket go higher by storing air pressure lost inside the rocket due to the launch tube coming out when the rocket is launched.

see linked video for a proof it works!
http://vids.myspace.com/index.cfm?fusea ... =157446586
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Post by rockets42 »

Interesting question. Class A rules clearly state that no launcher assist features are allowed. See rule I.5)

"Slingshots, trebuchets, catapults, cannons, and all other forms of launcher boost assist are forbidden"

Class B rules state the same thing, but say Launch tubes are allowed.

"Launch tubes (external or internal) are allowed as long as the internal pressure of the rocket is the only supply of energy." see rule I.5)

Now my interpretation of that says in class A you can't use a launch tube, but in class B you can since the additional clause mentioning of a launch tubes is included. A launch tube is clearly a launcher boost assist feature.

Because it says "internal pressure of the rocket is the only supply of energy" to me would mean that the launch tube has to be solid and not hollow, although it probably has to be hollow to let air in.

Now since ARBs are really an extension of the launch tube below the nozzle, it will be interesting to see what the admin has to say.

The rules don't cover anything about how far the launch tube and its capacity below the rocket can extend. Essentially you could just use a fat hose as your air supply line to act as an ARB since it could potentially have the same volume capacity as ARB bottles. The rules don't cover anything about the size of the hose so I would guess that ARB's could be used for class A and B. Since class A does not allow launch tubes ARBs probably would have no effect anyway.

And no I am not nit picking .....
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Post by WRA2 »

rockets42 wrote:Interesting question. Class A rules clearly state that no launcher assist features are allowed. See rule I.5)

"Slingshots, trebuchets, catapults, cannons, and all other forms of launcher boost assist are forbidden"

Class B rules state the same thing, but say Launch tubes are allowed.

"Launch tubes (external or internal) are allowed as long as the internal pressure of the rocket is the only supply of energy." see rule I.5)

Now my interpretation of that says in class A you can't use a launch tube, but in class B you can since the additional clause mentioning of a launch tubes is included. A launch tube is clearly a launcher boost assist feature.

Because it says "internal pressure of the rocket is the only supply of energy" to me would mean that the launch tube has to be solid and not hollow, although it probably has to be hollow to let air in.

Now since ARBs are really an extension of the launch tube below the nozzle, it will be interesting to see what the admin has to say.

The rules don't cover anything about how far the launch tube and its capacity below the rocket can extend. Essentially you could just use a fat hose as your air supply line to act as an ARB since it could potentially have the same volume capacity as ARB bottles. The rules don't cover anything about the size of the hose so I would guess that ARB's could be used for class A and B. Since class A does not allow launch tubes ARBs probably would have no effect anyway.

And no I am not nit picking .....
As long as the rules are followed the ARB acts like nothing more than an extra long air hose. The volume of air displaced by the launch tube is insignificant with respect to the total volume of the rocket, so the advantage of the ARB is only imaginary. It can be viewed as a liability when you consider that the air must be compressed in situ at the launch site and would take more time and effort.

ARB's cannot have more pressure in them than the rocket itself and cannot be configured in such a way as to have their energy applied to the outside of the rocket (this would be an air cannon), so dleatham can use them but just be sure to make it clear in any submission that the ARB is connected in parallel to the launch tube and there are no valves or regulators creating a differential pressure between the ARB and the pressure vessel.

Launch tubes are allowed for Class A. Is there a clarification needed to the class A rules? We wouldn't want someone investing a lot of time and effort on a non compliant design and having their claim denied. Feel free to offer suggestions to help us clarify this.
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Post by rockets42 »

The volume of air displaced by the launch tube is insignificant with respect to the total volume of the rocket, so the advantage of the ARB is only imaginary.
hmmm interesting, I wonder why people continue to use ARBs? Robert Youens sure did. I would have thought that a full length 22mm launch tube inside of a 30mm FTC rocket was not insiginificant. Even if the tube is hollow, it may not displace that much air directly but displaces the water which displaces the air. I think a good ARB in that situation could give you at least a 20% advantage.

But that's cool 8) that they are allowed in the competition. :)
Launch tubes are allowed for Class A. Is there a clarification needed to the class A rules?
Yes please. I was just curious why class A had not mentioned anything about launch tubes, but they were mentioned in the same clause in the Class B rules. Was the launch tube implied in class A, or the launch tube reference just missing?
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Post by Tim Chen »

My interpretation is that so long as you only put energy in the form of compressed air into the rocket and there's no other means of accelerating the rocket (like springs or slingshots) that a launch tube is fine. External reservoirs don't look like they would help at all because there would be no pressure difference between the rocket and the reservoir. If you used a reservoir to push a piston or used some kind of external launch tube fed by the reservoir then you'd be breaking the rules because you were using the launcher to push the rocket and not the rocket to push the launcher.
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Post by The Mooseheads »

...using the launcher to push the rocket and not the rocket to push the launcher.
I think you really nailed it, Tim. This could easily be reworded and added to the rules to clarify the idea!
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Post by WRA2 »

Tim Chen wrote:My interpretation is that so long as you only put energy in the form of compressed air into the rocket and there's no other means of accelerating the rocket (like springs or slingshots) that a launch tube is fine. External reservoirs don't look like they would help at all because there would be no pressure difference between the rocket and the reservoir. If you used a reservoir to push a piston or used some kind of external launch tube fed by the reservoir then you'd be breaking the rules because you were using the launcher to push the rocket and not the rocket to push the launcher.
Thanks for the suggestion Tim,

The launcher rules second draft is now posted in the WRA2 rules forum.
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Post by The Mooseheads »

WRA2 wrote:
Tim Chen wrote:My interpretation is that so long as you only put energy in the form of compressed air into the rocket and there's no other means of accelerating the rocket (like springs or slingshots) that a launch tube is fine. External reservoirs don't look like they would help at all because there would be no pressure difference between the rocket and the reservoir. If you used a reservoir to push a piston or used some kind of external launch tube fed by the reservoir then you'd be breaking the rules because you were using the launcher to push the rocket and not the rocket to push the launcher.
Thanks for the suggestion Tim,

The launcher rules second draft is now posted in the WRA2 rules forum.
I'll check it out. Thanks, Lisa.
Rick C.
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