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The Lemming Water Rocket Cannons

Principles

Documentation History

The first use of water rocket cannon in the SCA in Lochac (Australia) dates back to around 1990 when it was introduced by Lord Drew Steele. Drew's design featured a similar release mechanism to the one discussed below but used the power of the water rockets to throw a soft ball or a number of squash balls. Drew's cannon was used with limited success for two years before it stopped making an appearance.

The use of the water rockets cannons was revived in 1995 by Baron Tanw the Confused, head of the Lemming Household, when he built the organ gun pictured below. Tanw's gun originally fired 1.25 litre (35 fl oz) coke bottle that had a weighted and foam padded head and short plastic streamers for stability. In it's first incarnation the gun had only the lower 6 barrels which were fired simultaneously by pulling up a locking bar.

Baron Tanw the Confused's Organ Gun

The organ gun was not an initial success. Instability in the flight characteristics of the rockets combined with a non-existent elevation mechanism made hits a rare occurrence.

To combat the rockets inaccuracy the tactic developed of wheeling the gun up to near its minimum range of 10 meters (30 feet) behind a shield war. Just prior to firing the four fighters in front of the gun would stand aside to create a gap through which to aim. The addition of an elevation mechanism used in conjunction with the new tactic increased the gun's effectiveness to the point where if fired at a shield wall at minimum range, i.e. in ideal conditions, it would have a fifty / fifty chance of hitting.

Longer ranges or individual targets were, and still are, a problem. Beyond 10 meters the gun's performance quickly dropped off. At 20 meters the chance of hitting a shield wall dropped to about 1 shot in 10. Hitting an isolated target at that range was nigh on impossible.

About the middle of this period, or three years after the gun had come into action, we also came to the obvious realisation that having an experienced crew helped. In the early days finding crew who wanted work with the gun on repeated occasions was difficult, largely because of the effort involved.

Loading the organ gun takes a crew of two about 15 minutes which is usually all the rest allowed between battles. It also takes a lot of muscle power to pump up the bottles which leaves the crew tired before the battle even begins. The crew's involvement in the battle typically entails 1 minutes maneuvering followed by 5 seconds firing before they have to do all that work again. After an initial dearth of volunteers a few die-hards emerged who soon showed that even a couple of wars practice made a lot of difference.

The Lemmings (Blue and White) face off against Ventbarre.
The organ gun can be seen in front of the tree.

The gun's next incarnation included the addition of 5 new barrels on top of the existing six. Each of the new barrels could be fired independently which, as well as extra fire power, gave the ability to use the top barrels for ranging shots. With an experienced crew and the ability to fire of one or two shots to get the elevation right the guns accuracy increased to the point where the main volley almost never missed at minimum range. The long range accuracy, however, remained about the same.

The latest innovation has involved swapping the 1.25 litre bottles with 600 ml (17 fl oz) bottles and replacing the streamers with plastic or rubber fins. The fins greatly increase both the accuracy of the rockets and their range since the fins provide much less drag than the streamers. The new rocket design has yet to be tested in a battle.

In order to improve the appearance of their artillery the Lemming Household has embarked on the construction of their next cannon (pictures of the incomplete cannon are shown below). The cannons 'quintuple bored' barrel is based on a triple bored one built for Henry the Eighth while the carriage is loosely based on a drawing by Leonardo da Vinci.

Cannon in the Process of being constructed by Corin and Tanw

History

Documentation Operating Principles

The missiles used by the Lemming cannon are based on the same principle as employed by toy water rockets. A PET plastic drink bottle with a half tennis ball taped to the bottom end and fins or streamers for stability is used as the projectile.

The bottle is filled with an amount of water to act as the reaction mass and then locked into a breechblock. The breechblock mechanism consists of an airtight plug that fits into the opening of the bottle and a pin or slide that locks onto the lip below the screw thread, securing the plug into the bottle. The plug has a hole through the center to accommodate a tubeless car tire valve.

Once the bottle is fixed into the breechblock it is pressurized to 100 PSI with a hand pump of the kind used for inflating car tyres. A pressure gauge on the pump is used to indicate when the appropriate pressure has been reached.

The breechblock and pressurized bottle are placed into the breech of the cannon barrel and locked into place. The cannon is fired by pulling the pin / slide to release the bottle.

Older Rocket with polystyrene fins

Latest design Rocket with rubber fins

Diagram of bottle water rocket

Disassembled breechblock

Breechblock assembled with bottle locked in

Diagram of the breechblock mechanism

History

Principles Documentation

The following images are shown to demonstrate the kind historical sources that provided much of the inspiration for the Lemming cannons.

For many more images of pre 17th century guns visit the gallery.

Drawing by Leonardo Da Vinci of an organ gun and a modern construction based on his drawing. The carriage for the Lemming cannon is based loosely on this design.

Triple bored, breech loading cannon that was the inspiration for the latest Lemming cannon. It was commissioned by Henry the Eighth in 1533. The cannon currently is held in the Tower of London.

Two images from either end of the SCA period that provide examples of cannon projectiles for which the water rocket design provides a reasonable facsimile. The first is the earliest image of a cannon and dates from 1327. The projectile it fires is an iron arrow. The second image is a drawing by Leonardo Da Vinci of vaned cannon shell designs.

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Principles Documentation	History The first use of water rocket cannon in the SCA in Lochac (Australia) dates back to around 1990 when it was introduced by Lord Drew Steele. Drew's design featured a similar release mechanism to the one discussed below but used the power of the water rockets to throw a soft ball or a number of squash balls. Drew's cannon was used with limited success for two years before it stopped making an appearance. The use of the water rockets cannons was revived in 1995 by Baron Tanw the Confused, head of the Lemming Household, when he built the organ gun pictured below. Tanw's gun originally fired 1.25 litre (35 fl oz) coke bottle that had a weighted and foam padded head and short plastic streamers for stability. In it's first incarnation the gun had only the lower 6 barrels which were fired simultaneously by pulling up a locking bar.


	Baron Tanw the Confused's Organ Gun

	The organ gun was not an initial success. Instability in the flight characteristics of the rockets combined with a non-existent elevation mechanism made hits a rare occurrence. To combat the rockets inaccuracy the tactic developed of wheeling the gun up to near its minimum range of 10 meters (30 feet) behind a shield war. Just prior to firing the four fighters in front of the gun would stand aside to create a gap through which to aim. The addition of an elevation mechanism used in conjunction with the new tactic increased the gun's effectiveness to the point where if fired at a shield wall at minimum range, i.e. in ideal conditions, it would have a fifty / fifty chance of hitting. Longer ranges or individual targets were, and still are, a problem. Beyond 10 meters the gun's performance quickly dropped off. At 20 meters the chance of hitting a shield wall dropped to about 1 shot in 10. Hitting an isolated target at that range was nigh on impossible. About the middle of this period, or three years after the gun had come into action, we also came to the obvious realisation that having an experienced crew helped. In the early days finding crew who wanted work with the gun on repeated occasions was difficult, largely because of the effort involved. Loading the organ gun takes a crew of two about 15 minutes which is usually all the rest allowed between battles. It also takes a lot of muscle power to pump up the bottles which leaves the crew tired before the battle even begins. The crew's involvement in the battle typically entails 1 minutes maneuvering followed by 5 seconds firing before they have to do all that work again. After an initial dearth of volunteers a few die-hards emerged who soon showed that even a couple of wars practice made a lot of difference. The Lemmings (Blue and White) face off against Ventbarre. The organ gun can be seen in front of the tree. The gun's next incarnation included the addition of 5 new barrels on top of the existing six. Each of the new barrels could be fired independently which, as well as extra fire power, gave the ability to use the top barrels for ranging shots. With an experienced crew and the ability to fire of one or two shots to get the elevation right the guns accuracy increased to the point where the main volley almost never missed at minimum range. The long range accuracy, however, remained about the same. The latest innovation has involved swapping the 1.25 litre bottles with 600 ml (17 fl oz) bottles and replacing the streamers with plastic or rubber fins. The fins greatly increase both the accuracy of the rockets and their range since the fins provide much less drag than the streamers. The new rocket design has yet to be tested in a battle. In order to improve the appearance of their artillery the Lemming Household has embarked on the construction of their next cannon (pictures of the incomplete cannon are shown below). The cannons 'quintuple bored' barrel is based on a triple bored one built for Henry the Eighth while the carriage is loosely based on a drawing by Leonardo da Vinci.


	Cannon in the Process of being constructed by Corin and Tanw



History Documentation	Operating Principles The missiles used by the Lemming cannon are based on the same principle as employed by toy water rockets. A PET plastic drink bottle with a half tennis ball taped to the bottom end and fins or streamers for stability is used as the projectile. The bottle is filled with an amount of water to act as the reaction mass and then locked into a breechblock. The breechblock mechanism consists of an airtight plug that fits into the opening of the bottle and a pin or slide that locks onto the lip below the screw thread, securing the plug into the bottle. The plug has a hole through the center to accommodate a tubeless car tire valve. Once the bottle is fixed into the breechblock it is pressurized to 100 PSI with a hand pump of the kind used for inflating car tyres. A pressure gauge on the pump is used to indicate when the appropriate pressure has been reached. The breechblock and pressurized bottle are placed into the breech of the cannon barrel and locked into place. The cannon is fired by pulling the pin / slide to release the bottle.


	Older Rocket with polystyrene fins	Latest design Rocket with rubber fins


	Diagram of bottle water rocket


	Disassembled breechblock	Breechblock assembled with bottle locked in


	Diagram of the breechblock mechanism



History Principles	Documentation The following images are shown to demonstrate the kind historical sources that provided much of the inspiration for the Lemming cannons. For many more images of pre 17th century guns visit the gallery.


	Drawing by Leonardo Da Vinci of an organ gun and a modern construction based on his drawing. The carriage for the Lemming cannon is based loosely on this design.


	Triple bored, breech loading cannon that was the inspiration for the latest Lemming cannon. It was commissioned by Henry the Eighth in 1533. The cannon currently is held in the Tower of London.


	Two images from either end of the SCA period that provide examples of cannon projectiles for which the water rocket design provides a reasonable facsimile. The first is the earliest image of a cannon and dates from 1327. The projectile it fires is an iron arrow. The second image is a drawing by Leonardo Da Vinci of vaned cannon shell designs.