New oleopneumatic invention traction roller Dyneema

  • Up until now most of my diagrams have used estimates based on what the winding drum proportions look like in their profile photos when trying to put numbers on the gearing, but now inventor Andreas has published some numbers of his own. The original is in Greek, so the auto-translator has made a few errors, but you can understand it.


    In the Dreamair aluminum, the piston is 1000mm2 (ie 10Kg armature / atm pressure) with the simple armor having a maximum armature of about 8.5 atm. That is, arming starts at 85kg and ends at 60kg (CVT use). However, since the exterior with the inner winding drum does not start with a 1: 1 transmission ratio, you are arming from 75 kg to 60 kg. The piston at 8,5atm respectively starts charging at 85kg and ends up at about 130kg.

    In the Dreamair Unreal the piston is 500mm2 (that is, 5Kg of armature / atm pressure) with the simple armor having a maximum armature of about 16 atm and the difference between the initial and final power being about the same as the aluminum. In the Dreamair Unreal, the inner drum is not capable of a high call because it anchors within this inner rope of the gun and for this reason you manufacture the Dreamair Unreal with three balloons
    (three air chambers, a central cylindrical one and two flanking chambers as per the patent drawings).
    Dreamair fig 13 & 14.jpg

    The larger the two flanking chamber volumes are then the lower the compression ratio of the gun. In such an arrangement you can use a longer piston travel than you would have in a monotube as in the latter half the tube length travel takes you to a compression ratio of 2.0.


    We have not seen a cross-section of the "Dreamair Unreal" barrel tube, but the closest approximation would be the Sporasub "One Air" tank tube.

  • The possibility of making a "Dreamair" type of gun with dual power occurred to me while looking at an old diagram of the Mares partitioned reservoir system. In the Mares "Sten" and its many descendants and clones the gun can shoot with all the tank volume (full power) or just a fraction of it from what is often referred to as the pre-chamber (low power). Low power is approximately a half to a third of full power depending on how small the pre-chamber is. The presence of a one-way valve as well as a plug that closes or opens the partition in the gun's bulkhead that separates the tank volumes also allows easy loading in that the gun can be incrementally charged by repeated pushes on the spear during muzzle loading. For a "Dreamair" version this would translate to repeated pulls on the cable wishbone in an analogous process to the muzzle loading of the pneumatic.


    Maybe easier to draw than do, but here the concept is illustrated diagrammatically.

    It is the same idea, but turned back to front as in the "Dreamair" when the gun shoots the piston that hauls the cable flies rearwards inside the gun, not forwards. That means the power selector gate will be in the muzzle, however a remote control position may be installed at the rear handle by either a connecting rod or a hydraulic line to operate the selector switch.

  • The main difference, bar being "back to front", is that a pneumatic speargun is totally surrounded by its tank, whereas a "Dreamair" type gun has its tank on either side in two separate "pipes". The two pipes could be joined if the barrel was raised in the gun and the separate pipes were connected at the bottom. However such a shape may be difficult to produce and the rigidity would be different than a fully integrated central pipe top and bottom. The advantage would be only one plug power controller and one-way valve instead of two with the separate side tanks. In some guns, such as the old Scubapro "Magnum" and its "Vintair" successor, the plug and one-way valve are both combined in a system that functions similar to the "Sten" except that high and low power positions are reversed in the power selector gate. Like this version from Salvimar.



    tank with raised barrel.jpg


  • No, but given the use of more than two carbon fiber sub-components it will be expensive! There is the cylindrical central carbon fiber tube, the two flanking tapered side tank tubes (think of an oversize fishing rod butt end) and the body outer shell with muzzle and rear grip handle, all of which are aligned and bonded together in a monobloc construction. Compare that with a C4 Carbon that is just one component, although that component is cooked under pressure in a very expensive external mold. Then there are all the metal components, the CNC machined winding drums, of which there are three, and keyway axle and ball bearings and seals with their threaded mounts it is all going to add up.

  • The next two images show the gun body being moved back for the operator to grab the two “Dreamloader” handles that are now located just behind the pulley equipped hooks that are holding onto the cord wishbone. Once these handles are grasped they offer a two-to-one advantage in drawing the wishbone back. Knots strategically placed in the “Dreamloader” cords allow the handles to be slid forwards and engage the next set of knots so that the handles pull from further up the gun barrel each time. By working your way up the "ladder" of knots the wishbone can be drawn back to the rear shaft tab with a reduced pull effort, however the work done is still the same, but proceeds in stages to spread the effort. The pulleys in the hooks lock the cords and hold position while you slide the handles on the cords.



    loading dreamair unreal.jpg



    grabbing the Dreamloader handles.jpg

    • Helpful

    Andreas says the compression ratio is about 1.5. The central tube is a cylinder, but the flanking side tubes are tapered, so the volumes of these outer cones determines the compression ratio as well as the stroke of the piston in the central tube. Shorter or longer guns may have different tapers on their flanking tubes which would mean slight variations in the compression ratio for those guns. The shape of the outer hull determines what can be fitted inside it.

    Bear in mind that the discharged gun has the piston at the rear of the central tube. When you load it by drawing the wishbone back the inner cable draws the piston forwards to about half way up the central tube, this distance being dictated by the length of the spiral tracks on the inner and outer winding drums.


  • From the facebook page.

    In January 2020, a version of Dreamair Unreal was built with aluminium air barrels in order to reduce construction time and costs.

    Dreamair Unreal will be available in 3 versions:

    1) Dreamair Unreal with 3 air barrels made of Carbon Fiber with CNC & Filament Winding. It is the top version and supports the highest loads and performance.

    2) Dreamair Unreal with 3 air barrels made of aluminium, similar in architecture with CF. It is the middle class of charges, performance and cost.

    3) Dreamair Unreal with single aluminium air barrel which is the most economical version and supports the lowest loads and performance. In this version the load diagram is not inverted and looks like conventional airguns.

    Dreamair Unreal with aluminium air chambers does not show galvanic corrosion between carbon fiber and aluminium (there is a relevant guarantee).

    The Dreamair Unreal with single aluminium air barrel can be loaded with 26 bar pressure max and it will be the first to be available.
    Cost of first guns is around 800 euro.


    You can place an order now for the number 3 model by emailing the inventor/manufacturer zournatzis@gmail.com.

    I think this is a batch price and not the price of one gun being ordered on its own.


    Edited 3 times, last by popgun pete: added an image ().

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