Dreamair Pneumatic Cable Drive Speargun

[popgun pete]

The Infinitengines Company has been developing their "Dreamair" pneumatic speargun for many years. It is basically a high speed winching system where compressed air in the gun body is further compressed when you cock the gun by moving a large piston. Unlike nearly every other pneumatic speargun the piston is dragged forwards in the gun when you cock it and when the gun shoots the piston travels rearwards. The reason for this is the piston is attached to a cable that winds on and off an inner axle inside the pressurized spaces of the gun. On the exterior of the gun and mounted either side of the same axle are winding drums that that are turned and haul the long cable wishbones in that pull on the shaft. So externally it looks much like a band gun, but instead of rubber bands the cables wind up on the external grooved drums when you shoot and when you pull the cable back to cock the gun that action rotates the drums and axle and a co-axial inner drum that via an inner cable hauls the internal piston forwards thereby recharging the gun for the next shot.

Recently a Carbon version of the "Dreamair" was announced, the first version was an alloy gun that has never been marketed as a couple of years ago the company suddenly decided that more divers would be interested in a carbon fiber version of the gun.



https://www.youtube.com/watch?time_cont ... ZnqMrFt7ys

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This diagram shows the outer cable/wishbone track in plan view as the gun shoots. Cocking the gun the process is reversed.

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By the way the guns do work as this fish had an encounter with one.

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Here is the gun layout drawing. The patented design has multi-axle versions, however these allow an incremented loading of the gun as each wishbone draw would haul the piston along the pressure barrel in stages. For example a twin axle gun would pull the piston forwards to the half way mark with the first wishbone draw, then the second wishbone draw would complete the cocking of the gun. The second wishbone draw would be more difficult than the first, but would allow the gun to be used at a higher loading pressure. For now the gun is loaded in one draw, but a very clever loading gadget can break this up using twin pull handles and a system of knotted cords and hooks that engage the wishbone. In the YouTube video you can see these at work as there are two versions.

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Servicing the gun has not been neglected, anyone could do it if they have the ability to use simple tools that will be supplied with each gun.

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A schematic showing an overview of the major components. The winding drum covers part 6 have proven not to be needed.

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Here is the second version of the loader which utilizes the "block and tackle" principle, i.e. pull for twice the distance, but half the force level. The same amount of work is involved, but is a more distributed effort.

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A close-up of the loading handle slots that catch onto knots in the cord.

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A new photo of the "Dreamair Unreal" has just been added to the site. It appears to not have the outer drums fitted as you can see the ends of the axle.

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These guns are now able to be ordered and will be built in batches. The first version being offered has a carbon fiber body and an inner alloy tube buried inside the gun for the piston to travel in. These guns have a cylindrical drum inside and the outer beehive shaped spiral track drums, so the latter drums provide the leverage changes as you pull the wishbone back. Price of these carbon fiber guns is 800 euro. Later carbon fiber versions will have a variable profile inner drum and flanking alloy tubes buried inside to provide a different compression ratio by increasing the head space (think of the cylinder head on an automobile engine) inside the gun, while the top version will be all carbon fiber with filament wound tubes for the central and flanking tubes.

[popgun pete]

Here is a video of the carbon fiber, single alloy barrel gun in action. The alloy barrels have been introduced to make for easier and faster constuction at a more economical price.
https://youtu.be/E9-hmkNtW6Y

The carbon fiber guns have a different construction as can be seen here.

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For those wondering why a gun should be made this way the answer is that it allows a big piston pneumatic gun which for a given pressure level has a lot of force to propel a spear. Standard pneumatic guns would have to push a large column of water using a large diameter piston, but here instead of the piston being where the pressure boundary is crossed in the “Dreamair” it is the axle that does that. Consequently the inner parts of the gun are never exposed to water as internal motions are transferred by a cable turning the axle via an inner drum and that creates a winching system using the outer drums that drives the spear from the gun using a cable wishbone.

[Donzi Paul]

Peter thanks for posting the innovative Dreamair gun over as well.

All the best, Don

[popgun pete]

800 euro is about what you would pay for a C4, although this gun has a lot more parts than one of those, especially with the machined inner and outer drums and the roller bearing axle isolated by pressure seals. You also get a hand pump and a Dreamloader which is shown above. The pulley sitting on top of the rear butt is used with the Dreamloader instead of using a shaft notch or tab as a rear anchor for the Dreamloader cable.

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A dinner guest. Stratis Gelagotis with catch.

[Donzi Paul]

Wow,,,so cool Peter, Looks like it works great mate.


Cheers, Don

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Bagging a Dentex.

[Donzi Paul]

Quality fish


Cheers. Don

[popgun pete]

The guns from the first production batch have been delivered to their owners.