New Competition Class

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The Sky Dart
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Re: New Competition Class

Postby The Sky Dart » Sat Sep 26, 2009 6:45 pm

andicirk wrote:reading this with interest although im a little confused about the cheap 250 psi compressors ( they dont exist where i live , cheap compressors are still $100 and are maximum 8 bar which is a long way shorrt of the 250 psi mark)

other than that all good

andi


How about something like this:

http://www.justoffbase.co.uk/Mini-Air-C ... ey-MAC1250
http://www.m-99.co.uk/Electrical/Car_Ai ... essor.html

Even ordered from the UK it'll be less than 100USD.
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Re: New Competition Class

Postby andicirk » Sat Sep 26, 2009 8:19 pm

ok i didnt think of 12 volt car compressoers but , most of them lie , ie 250 psi compressor etc and it only goes up to 8 bar 135 ish, so if anyone has tested any of these id be interested to hear
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Re: New Competition Class

Postby U.S. Water Rockets1 » Sat Sep 26, 2009 10:29 pm

andicirk wrote:ok i didnt think of 12 volt car compressoers but , most of them lie , ie 250 psi compressor etc and it only goes up to 8 bar 135 ish, so if anyone has tested any of these id be interested to hear


We reported on the fake claims of compressors many years ago in our news story: http://www.uswaterrockets.com/business/ ... ory_01.htm but we had been using a 300PSI compressor. The ones we tested could reach the rated pressures but we had to follow very strict instructions in the manual that prescribed how long the compressor had to cool off and how long it could run continuously. In all cases even following the procedures in the manual, the nylon gears would wear out after several uses. It should be possible to change the plastic gears for metal ones and make these into a useful compressor.
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Re: New Competition Class

Postby The Sky Dart » Sun Sep 27, 2009 4:09 am

andicirk wrote:ok i didnt think of 12 volt car compressoers but , most of them lie , ie 250 psi compressor etc and it only goes up to 8 bar 135 ish, so if anyone has tested any of these id be interested to hear

We've been using a one similar to the posted above (http://sites.google.com/site/theskydartteam/projects/pdu). At this moment we are not able to verify whether 300psi are indeed 300psi, but the pump gets to the end of its manometer without any problems. We thought about adding a cooling fan to the pump, but at the end decided to leave it to a later stage.
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Re: New Competition Class

Postby WRA2 » Thu Oct 08, 2009 4:15 pm

1ST draft of new competition class rules.


I. WRA2 Altitude Challenge Design Parameters

1) Rocket must reach record altitude using a single stage. Multiple Stage Water Rockets compete in the WRA2 Class B. More discussion needed to determine if single or multiple stages are allowed.
2) Rocket must use Water as its primary reaction mass.
3) Water Rocket must use compressed ambient atmospheric air at no more then 200 PSI (250?) as its energy. Other gasses have much higher compression ratios and there needs to be a baseline so the record is fair to all. (see section II for special rules regarding bottled air).
4) Pressure Vessel and Fuselage of Rocket must be constructed from lightweight nonmetallic materials.
5) Rocket must be launched from a stationary position on a fixed launcher. (Slingshots, trebuchets, catapults, cannons, and all other forms of launcher boost assist are forbidden). Launch tubes are allowed as long as the internal pressure of the rocket is the only supply of energy.
6) Rocket must be completely scratch-built using materials which are not manufactured for model rocket parts. (with the exception of the Camera and Altimeter) Raiding hobby shops for nosecones, or fins, or any other pre-manufactured items is prohibited.(manufactured items that are not designed for rocketry such as wind up toys are allowed)
7) Rocket must carry onboard a commercially produced recording ("Logging") altimeter to document the entire flight on a Time vs. Altitude Graph to nonvolatile logging memory or telemetry to relay the altitude information to a remote logging receiver. Ground based and/or timing based altitude measurements are too error prone and are unacceptable. Discussion needed to determine the use of “peak altimeters” (if peak altimeters were to be used then the ground video must show the altimeter display after each flight)

So-called "Peak Altitude" altimeters are also unacceptable because they are subject to false peak readings caused by external factors such as:


• Recovery system deployment.
• Landing impact.
• Improper installation.
• Unstable flight characteristics.

8) Flight must be recorded by ground-based video to validate flight duration and recovery. It is required proof the flight actually happened. (if using bottled air is used then the 10 minute max pressure hold must be shown) Ground video must show launch pressure used.
9) Entire flight including apogee must be photographed by an onboard video camera.
10) Record Altitude is calculated as the average of the two highest flights the rocket achieves within a 2-hour period. This prevents dumb luck, the “perfect storm” scenario or false readings from giving a false record. Results must be repeatable!

This criteria was inspired by high profile competitions such as the Ansari X-Prize.
11) The same rocket must be used for all averaged flights. The only portions of the rocket which can be replaced are expendable or consumable items. (batteries, tape, deployment chemicals, water, etc..) The same rocket must be used for all attempts. Items which are damaged in any record attempt must be repaired and reused. Any competing rocket must be sturdy enough to survive multiple launches and the recovery system must be robust enough to prevent damage. “Expendable” rockets are disallowed from competing.

II. Bottled Air Rules (do we restrict to only compressors and manual pumps?)

1) Only bottled atmospheric air is allowed. No exotic gasses, cryogenics or combustibles.
2) Tanks must be certified. (copies of tank certifications will be provided and filling station receipt).
3) All local laws must be complied with for handling pressurized tanks as well as any certifications that the operator may need will also be provided upon a record submission.
4) To prevent "stomp rockets" the rocket must remain pressurized to full launch pressure for a period of no less then ten (10) minuets. (The ground view camera will show both the tank and rocket on the launcher during this 10 minute period).
5) Bottled air pressure source must be located at the minimum safe distance of 50 Feet (15 meters) from the launcher (this allows the bottled air pressure source to be safely controlled in the event of an emergency).

III. Safety Rules

1) All WRA2 Water Rocket Safety Rules must be followed.

2) All launched parts of rocket which travel over 6 meters (20 feet) in altitude must have a recovery system which limits their descent rate at time of touchdown at ground level to a maximum velocity of 10 meters/second (33 feet per second) This includes all pieces which separate or are shed off in flight. Fast falling rockets, boosters, debris, or rocket parts can be very dangerous. Recovery system malfunctions for any part will disallow any record flights.

IV. Pressure Vessel Rules

1) Rocket cannot exceed 1,500 grams empty (no reaction mass).. More discussion needed to decide if the limit can be 1000 grams?
2) Pressure vessel must be entirely fabricated by the rocket builder.
3) Pressure Vessel cannot be constructed using any portion of an existing high pressure enclosure. (i.e. no Paintball tanks, CO2 tanks, SCUBA tanks, Propane Tanks, etc.). The object is to engineer and build your rocket yourself.

4) Pressure Vessel and all external parts of the rocket may not be fabricated from metal. (see the WRA2 water rocket safety rules).

5) Pressure vessel must be entirely fabricated by the rocket builder.

V. Reaction Mass Rules

1) Reaction Mass must be primarily ordinary tap water.
2) Thrust must come from expelling reaction mass, not from air discharge. That would be considered an Air Cannon projectile.
3) Water Reaction Mass must fill a minimum of 20% of the volume of the Pressure Vessel. Token amounts of water added in an attempt to qualify an air cannon projectile as a water rocket are not allowed.

VI. Filing a Record Claim

1) All record claims must be filed to the WRA2 Contest Submissions for public review.
2) Items required:

-Onboard video for both flights.

-Ground videos for both flights

-Raw altimeter data for both flights

-Time and date for each flight.

-If using bottled air: copies of the tank and operator certifications.

Optional Items:

-Design drawings

-Detailed still photos

-Simulator data

3) Maximum file size 20MB per file
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Re: New Competition Class

Postby The Sky Dart » Fri Oct 09, 2009 5:19 pm

0) What is the name of the class going to be? I suggest "Class D"

1) Rocket must reach record altitude using a single stage. Multiple Stage Water Rockets compete in the WRA2 Class B. More discussion needed to determine if single or multiple stages are allowed.

Limit entries to a single stage. As soon as the class is not the open one, there is no reason to make it complicated.

3) Water Rocket must use compressed ambient atmospheric air at no more then 200 PSI (250?) as its energy.

I am for 250 psi. As I commented already, this level is safe enough, but at the save time challenging enough to create a good healthy competition.

6) Rocket must be completely scratch-built using materials which are not manufactured for model rocket parts. (with the exception of the Camera and Altimeter) Raiding hobby shops for nosecones, or fins, or any other pre-manufactured items is prohibited.(manufactured items that are not designed for rocketry such as wind up toys are allowed)

How about servos?

7) Rocket must carry onboard a commercially produced recording ("Logging") altimeter to document the entire flight on a Time vs. Altitude Graph to nonvolatile logging memory or telemetry to relay the altitude information to a remote logging receiver. Ground based and/or timing based altitude measurements are too error prone and are unacceptable. Discussion needed to determine the use of “peak altimeters” (if peak altimeters were to be used then the ground video must show the altimeter display after each flight)

Several questions here:
1) What exactly constitute "commercially produced recording ("Logging") altimeter"?
2) I think any recording altimeter should be allowed as soon as strong evidence of their correct calibration is provided. At the end buying an altimeter does not guaranty its correct operation.
3) I think peak altimeters should be allowed. However, a number of mandatory flight should be increased to, for example, 5


10) Record Altitude is calculated as the average of the two highest flights the rocket achieves within a 2-hour period.

Two flight in case a recording altimeter is used and 5 flights in case of a peak one

1) Rocket cannot exceed 1,500 grams empty (no reaction mass).. More discussion needed to decide if the limit can be 1000 grams?

I am for 1000 grams for the same reason as for 250psi. Limiting mass will inspire competition in reducing the payload mass

5) Pressure vessel must be entirely fabricated by the rocket builder.

point 5) repeats 2). Should be deleted

3) Water Reaction Mass must fill a minimum of 20% of the volume of the Pressure Vessel. Token amounts of water added in an attempt to qualify an air cannon projectile as a water rocket are not allowed.

Two thoughts here.
- How is it to be controlled?
- I suggest 15% instead of 20%
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Re: New Competition Class

Postby SaskAlex » Fri Oct 09, 2009 7:31 pm

I also think we should keep it to one stage. The current two stage record isn't that high. If anyone is serious about making two stage rockets, they can compete in class B.

I think either 200 psi or 250 psi are fine.

I'd say servos should be allowed. Never used one myself, but they seem pretty popular. And I don't really think they are intended for model rockets.

My vote is to allow peak altitude altimeters, and I think a five flight average sounds fair enough. I also think all flights should be within a 10% range. And of course, the standard two-flight average would hold for logging altimeters.

As for ground video showing launch pressure, I definitely think it's necessary. Unfortunately, I don't know just how accurate everyone's gauges will be, but I think that's something we will just have to live with.

I think 1000g limit might be a good idea, too. It makes it more about making quality rockets, not just giant ones.

As for fill level, I don't see why anyone would put less than 20% water in a true water rocket. I don't think it should be lowered. As for controlling it, it would be the same as all the other rules: the honour system.

It's looking pretty good to me.

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Re: New Competition Class

Postby RaZias » Sat Oct 10, 2009 4:25 am

The 200 or 250 psi should depend of the avaiability of the pressure pumps in the market.

I think the pressure should stick to the most easy to find in the market.

That´s the reason of this new class, the avaiability of making this type of rockets, otherwise it would run in the same problem as the world record class...no one knows how to find a 2000psi compressor.

One solution is to the who makes the records to post to public in the forum the compressor or pump that was used.
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Re: New Competition Class

Postby andicirk » Sat Oct 10, 2009 4:51 am

That´s the reason of this new class, the avaiability of making this type of rockets, otherwise it would run in the same problem as the world record class...no one knows how to find a 2000psi compressor.

One solution is to the who makes the records to post to public in the forum the compressor or pump that was used.


i can find a 2000psi compressor no problem , i just cant afford it .......

i think the main problem is going to be finding a reasonable 250psi compressor that is capable of launching the wrockets without melting...
so are we allowed to modify the 12volt car compressos etc so they can run cooler ?
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Re: New Competition Class

Postby The Sky Dart » Sat Oct 10, 2009 9:04 am

andicirk wrote:
That´s the reason of this new class, the avaiability of making this type of rockets, otherwise it would run in the same problem as the world record class...no one knows how to find a 2000psi compressor.

One solution is to the who makes the records to post to public in the forum the compressor or pump that was used.


i can find a 2000psi compressor no problem , i just cant afford it .......

i think the main problem is going to be finding a reasonable 250psi compressor that is capable of launching the wrockets without melting...
so are we allowed to modify the 12volt car compressos etc so they can run cooler ?


Well, I personally can't see why not. At the end it's about rockets, not compressors. I would say any kind of compressors including DIY onse should be OK as long as the required pressure is confirmed.
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Re: New Competition Class

Postby SaskAlex » Sat Oct 10, 2009 3:21 pm

And if anyone is concerned about the safety of modified compressors, make them remotely operated. For those 12V car ones, it would be as simple as extending the power cord. Also, this means you don't need 50 feet of high pressure air line. You just need a big pressure gauge, and maybe binoculars.
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Re: New Competition Class

Postby The Sky Dart » Sat Oct 10, 2009 4:47 pm

SaskAlex wrote:And if anyone is concerned about the safety of modified compressors, make them remotely operated. For those 12V car ones, it would be as simple as extending the power cord. Also, this means you don't need 50 feet of high pressure air line. You just need a big pressure gauge, and maybe binoculars.

This is exactly how we do it spare the binoculars.
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Re: New Competition Class

Postby U.S. Water Rockets1 » Sat Oct 10, 2009 10:45 pm

The Sky Dart wrote:
SaskAlex wrote:And if anyone is concerned about the safety of modified compressors, make them remotely operated. For those 12V car ones, it would be as simple as extending the power cord. Also, this means you don't need 50 feet of high pressure air line. You just need a big pressure gauge, and maybe binoculars.

This is exactly how we do it spare the binoculars.


You could also use a radio transmitter camera or a webcam to see the pressure gauge. We did this when we were pressure testing our very first designs. There's a video where we show a pressure test explosion and another one where we show a compressor failure and those we both done with remote video.
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Re: New Competition Class

Postby Cloud Dancers » Mon Oct 19, 2009 9:57 pm

The Sky Dart wrote:0) What is the name of the class going to be? I suggest "Class D"

1) Rocket must reach record altitude using a single stage. Multiple Stage Water Rockets compete in the WRA2 Class B. More discussion needed to determine if single or multiple stages are allowed.

Limit entries to a single stage. As soon as the class is not the open one, there is no reason to make it complicated.

3) Water Rocket must use compressed ambient atmospheric air at no more then 200 PSI (250?) as its energy.

I am for 250 psi. As I commented already, this level is safe enough, but at the save time challenging enough to create a good healthy competition.

6) Rocket must be completely scratch-built using materials which are not manufactured for model rocket parts. (with the exception of the Camera and Altimeter) Raiding hobby shops for nosecones, or fins, or any other pre-manufactured items is prohibited.(manufactured items that are not designed for rocketry such as wind up toys are allowed)

How about servos?

7) Rocket must carry onboard a commercially produced recording ("Logging") altimeter to document the entire flight on a Time vs. Altitude Graph to nonvolatile logging memory or telemetry to relay the altitude information to a remote logging receiver. Ground based and/or timing based altitude measurements are too error prone and are unacceptable. Discussion needed to determine the use of “peak altimeters” (if peak altimeters were to be used then the ground video must show the altimeter display after each flight)

Several questions here:
1) What exactly constitute "commercially produced recording ("Logging") altimeter"?
2) I think any recording altimeter should be allowed as soon as strong evidence of their correct calibration is provided. At the end buying an altimeter does not guaranty its correct operation.
3) I think peak altimeters should be allowed. However, a number of mandatory flight should be increased to, for example, 5


10) Record Altitude is calculated as the average of the two highest flights the rocket achieves within a 2-hour period.

Two flight in case a recording altimeter is used and 5 flights in case of a peak one

1) Rocket cannot exceed 1,500 grams empty (no reaction mass).. More discussion needed to decide if the limit can be 1000 grams?

I am for 1000 grams for the same reason as for 250psi. Limiting mass will inspire competition in reducing the payload mass

5) Pressure vessel must be entirely fabricated by the rocket builder.

point 5) repeats 2). Should be deleted

3) Water Reaction Mass must fill a minimum of 20% of the volume of the Pressure Vessel. Token amounts of water added in an attempt to qualify an air cannon projectile as a water rocket are not allowed.

Two thoughts here.
- How is it to be controlled?
- I suggest 15% instead of 20%


Here is my 2c

1 limit the pressure to 200psi, I can buy a compressor that will do that at my local hardware store.

2 keep the maxximim weight to 1500 grams

if higher pressures are allowed along with a lower weight limit then I may as well compete in the other classes. Someone will just build a super strong and light rocket to win it. With the weight at 1500 and the lower pressure limit of 200 it will open the door to all kinds of different possibilities like spliced rockets. 200 is enough so that a person have a choice to reinforce or to build a larger volume unreinforced rocket using less pressure and both would fit in the rules.

3 I think 3 flights in 2 hours would be a good limit if peak altimeters are allowed. That might get more people interested in competing because the cost would be lower. The only problem would be in the reporting of the altitude. If I remember correctly from the antigravity video their peak altimeter beeped out the maxximim altitude. The person filming on the ground would have to videotape the altimiter showing the altitude of each flight like antigravity did.

4 Keep the camera, those things are cheap enough these days and the videos are always cool to watch.

5 Keep it one stage, KISS.
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Re: New Competition Class

Postby Tim Chen » Tue Oct 20, 2009 9:59 pm

If you limit the weight then the volume will naturally be lowered and that will make it easier for a pump to last. A huge rocket will be hard to pump up to 200PSI because the pump's gotta run so long it will get too hot and melt the gears. I like the proposed 1500g limit and the pressure limit of 200PSI. That should make it so that anyone can find a pump that will be capable.
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