Posts by popgun pete

And more of the gun itself.

Some new material which has just appeared.

Spinal surgery, none of the patients recovered, but were able to serve in the kitchen.

The much and probably deservedly maligned full-face snorkel dive mask may be getting a new lease on life as it may help in supplying protective breathing gear for hard pressed medical workers by providing a reusable mask that completely shields the face.

Ocean Reef Launches Adaptor To Change Full-face Snorkel Mask Into COVID-19 Protective Mask | Scuba Diver Mag

Ocean Reef, which produces full-face diving and snorkelling masks, has created an adaptor which will fit to their snorkelling product and transform it into a COVID-19 protective mask.
http://www.scubadivermag.com

Here are modified dive masks already in action produced by another group. As the situation worsens there has been a shortage of protective gear, much of it single use, but here only the cartridge needs replacing as the masks are able to be cleaned.

Closest that I can get to freezing the moment of the shot on the last fish at about 2.27 seconds into the video. Note the cavitation bubbles in the shaft’s wake along the top deck.

More shots.

Some shots

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.

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.

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).

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.

Nice job, I like the 3 porthole muzzle! Curving the lower section of the stock to match the Riffe handle is often a turn off for those contemplating using that handle, but at least you had the damaged stock to work with.

The gun and its victim.

This is how it was originally set up. The drums have to rotate in the opposite directions if they pull from on top.

Still dreaming!

Another morsel of information.

Spearing with the Dreamair Unreal

You probably need to make a few of them if you plan to use it as pins are easily dropped and impossible to find.

Feeding on shark by hand is perfectly acceptable.

Sharks have never quite mastered the "don't bite the hand that feeds you"!

Interesting to see two into one bands on each side.

A victim of the Pelengas Max.(from the official Pelengas Facebook page)

A "Horseshoe Crab" I think that they are called, saw them on a TV show about both them and another living fossil the Chambered Nautilus. From memory a dish was prepared from one which was not particularly appetizing and involved the creature's eggs which are contained in the horseshoe shape around the head. Closest thing to a Trilobite which once was the dominant species in the oceans millions of years ago. Apparently their blue blood is used for testing of biological contamination in laboratories due to some unique properties which have enabled the species to survive the millennia without getting diseased by bacteria and pathogens.