Posts by popgun pete

Quote from Don Paul

Pete I wonder if this piston damper and bits have recently been added to the prototype design?
That could be the reason for a delayed production. I really like the use of fluid dynamics to help slow down the piston energy. I cant wait to put one of these guns in my sons collection some day.

Cheers, Don

Yes, I think that could be the reason as the piston slamming into the rear bulkhead would deliver a substantial thump to the structure of the gun if there was no shock absorbing system in place. The conical nose of the rear bulkhead, and the matching recess in the rear end of the sliding piston, were probably shaped that way as a form of hydraulic shock absorber using the existing oil supply in the rear tank, but with the oil pooling at the bottom of the tank (due to gravity with the gun held horizontally) it would be forced upwards only in the very last section of piston travel. Hence the hydraulic action shock absorber would be deprived of a fluid to pump and would then be effective only when the volumetric capacity available had substantially closed up.

A shock absorbing column using an oil damper arrangement is now used to slow the sliding oval piston down before it strikes the rear bulkhead during the shot. A composite photo indicates how this additional refinement has been integrated into the conical nose of the rear bulkhead.

Some information supplied by the "Infinitengines" Company concerning the current gun's physical dimensions.

The size of the "Dreamair" speargun is 110 cm (130 cm overall length). The dimensions of the oval barrel tube are 55 mm x 38 mm. (Note that a "standard" pneumatic gun, e.g. Mares "Sten", has a 40 mm OD tank tube with a 38 mm ID.) The weight of the gun without the spear is 1800 g and the gun can shoot spears from 6.5 mm to 8 mm in diameter with 150 cm length; spear shafts of a diameter larger than 8 mm can be used if a flotation element is added to the gun. The "Dreamair" speargun can be manufactured in various barrel lengths.

The winding drums and rotating axle are seen in this annotated photo. Note that the engineering design is very advanced for a speargun of any type and demonstrates that this is a serious effort to produce a gun that operates on an entirely different principle to anything that has gone before.

Quote from Ramon

PETE To me it seems strange to see photos without firing a rifle support for video and any video
I only see a gun in plane with a bunch of little pieces and the cost of its realization can be very expensive
that has an exit on the market.

A rifle shots, theoretical is one thing in practice is another, already you discuss Mr Andreas Zournatzis by direct message
on his Facebook profile and I promised that in the autumn of 2015 would be completed and tested, I've only seen what
I comment above.

https://www.facebook.com/ramon.javier.B

A mi me parece raro ver fotos sin disparos, un soporte en el fusil para video y ningun video
solo veo un fusil en plano con un monton de piececitas y el coste de su realizacion puede ser carisimo y que tenga salida en el mercado.

Un fusil en planos, teorica es una cosa en la practica es otra, Ya se lo comente al Sr Andreas Zournatzis por mensaje directo
en su perfil de Facebook y me prometio que en otoño del 2015 estaria terminado y probado, solo he visto lo que comento arriba.

Display More

I have no idea why there is a delay in these things being made available, however logic would suggest an unexpected problem or difficulty in sourcing some component that has made the project run later than expected. Sooner or later we will find out, but for now all we can do is wait.

A close encounter with the "Dreamair" turns a dream into a reality. (from the "Infinitengines" Facebook page)

Inner cables are routed around a pulley on the front of the piston, in fact there is only one inner cable which attaches to each axle's inner winding drum. A means to opposing their travel is shown here by reversing one of the inner drums. Multi-axle versions (more than 2) would need to separate the cable runs to avoid unwanted interactions between them.

Now shown in separate diagrams which makes the cable on winding drum process much clearer.

Another view of how the winding drums operate, there being separate inner and outer cables whose length is dictated by the lengths of the spiral tracks on the respective drums. Thus for the same number of axle revolutions each cable is hauled in, or let out, at different rates and different lengths.

Looks like the "Dreamair" is getting its feet wet here. Cocked to shoot and targets lined up at a distance. All we lack is the shaft heading out and hauling the shooting line behind it, note the number of wraps on the line release finger.

Photos taken from the web-site circa September 2016.

Here is a ”Hurricane” brochure/advert both in French and English where we can see exactly what the claims are for the “Carabine” dry spring guns. They are for the most part either wildly optimistic or deliberately misleading lies!

Immediately the claimed shooting ranges are seen to be beyond being optimistic, they are impossible (for straight line, horizontal shaft flight). The working course of the piston in these dry spring guns is too short to deliver the performance stated here. The reference to a “pneumatic surcompressor” is also a lie as to be a surcompressor the air pressure in the guns would need to be well above ambient pressure, but any gun you can pump up with your thumb or finger acting as a non-return valve on the hole in the rear of the pump handle can only be pumped to slightly over ambient pressure before it again equalizes with the surroundings. The lack of any seals on the sliding piston and the sear tooth acting on its leading edge make elevated pressure behind the piston impossible as any air present inside the gun barrels is always connected front and rear. The “Carabine surcompressor” is the equivalent of blowing water clear of a drinking straw placed at the bottom of the glass, excess air bubbles out and if you close the top of the straw off by placing the tip of your tongue over it then the straw’s interior stays dry, but only while the rear hole is kept blocked off. In the “Carabine” gun a one-way valve does this job, but if you lift the muzzle up past the horizontal then air will bubble out of the muzzle as water gurgles in to fill up the gun. Dive down and water will penetrate along the barrel as pressure inside the guns equalizes with pressure outside at the tip of the muzzle. Hence the “Carabine” is a type of diving bell which is open at the bottom rather than a pressure sealed gun. Many of the claims here are basically over blown BS.

No doubt “Carabine” speargun owners, having paid a lot of money for their guns, kept quiet about their disappointment, either that or their expectations were very low in the first place.

The original 1945 French patent diagram and what was really inside the gun once the sealed grip handle was removed.

These two French "Hurricane" brochure pages show the four "Carabine" models; the "Mosquito" being the shortest version and the "Rafale" the longest version. The "Carabine" guns were produced throughout the forties, but by the fifties it was obvious that the pneumatic guns would soon eclipse their performance once they stopped leaking air. Many earlier pneumatic spearguns had a built-in hand pump to add more air as required, but not while in the water of course. Once the pressure sealing was made good enough to hold air for weeks, if not months, then the "Carabine" guns were well and truly obsolete, as in a sense a pneumatic gun is the perfect spring gun using a pressurized column of air as its "spring". With no (or very slow) air leaks, then the pneumatic gun hand pump could be a separate component and not built into the fabric of the pneumatic gun.

Back in the period just after the conclusion of WWII inventors were competing to produce the best spearfishing gun, and due to the reliability of spring propulsion a lot of effort was expended in that area.

One solution was to have a "dry spring gun" where you either tipped the water out or pumped it out and the latter system was perfected by Pierre Martineau. His French "Hurricane" brand also produced some of the first rollerguns, so he was a prolific inventor and saw most of his ideas put into production, and that included the "Carabine" dry spring gun. Unfortunately it was only dry after you had pumped it out, so the springs needed to be cleaned or at least rinsed because when you muzzle loaded the gun the seawater gurgled down the barrel and filled the gun up. The diagrams and photos show how the gun worked, but only recently has one been opened up to check what is inside and there were a few surprises.

Cleaning one of these heavy guns would have been a lengthy task as with no holes in the barrel tube the gun’s interior would not have dried out any time soon. A number of "Carabine" guns survive as owners no doubt abandoned their use once good rubber for band guns arrived, and the perfected pneumatic gun was many times more efficient than any spring gun as the buckling coils rubbing on the barrel tube dissipate energy that could otherwise have been used for spear propulsion.

Seems that the old plastic reel has passed into history, but you can see them here and there must be something very similar today.

Academy – Australian Fishing Museum

http://australianfishingmuseum…DEMY_FISHING_REEL_020.JPG

This one is green, but they were either black or white when I was buying them.

Guys remember what will be at the other end of this sling type shooter, a fish of modest proportions for which the sling has been selected. Line handling and retrieve is the key attribute here, so reel quality and capacity needs to be matched to the job. The "Academy" reel was cheap and cheerful in its day and I am sure a simple drum reel equivalent is all that is required. From memory the "Academy" reel was $4.00 and many spearoes of my vintage used them as a simple line gatherer fit for the modest task required of it. Of course that was about 30 years ago!

Here is another of my home-made guns with an "Academy" reel, on this one I kept the "clicker" by making a new flattened control lever. Used for grouper and other reef residential fish the long 3/8" shaft did the damage and the fish never ran far heading for their nearest bolt hole. Line retrieve was important as this gun has line wraps on each side running the full length of the gun. Now retired and restored as the era it was used in has passed, its potential victims are now protected species as less discriminating spearoes nearly wiped the big ones out and are only now recovering their numbers.

Quote from silverspearo

Thanks for taking the time to reply Pete - good quality brass for me then - with a small hole to avoid a splitting I'm thinking! You've got my imagination going with a oranger head and have to see one of these! I simply must have one as it sounds so cool ; ) I'll google it and see what comes up.

Off spearfishing from the shore nw Anglesey - an island off North Wales early next week so make have a go with a longer line and an old fly reel I own - and then think about a more permanent rig taking on board some of these suggestions.

Best wishes Rick

Sent from my iPhone using Tapatalk

Display More

Here is the front end of that gun with the pranger head. This is a short tine or barb version, there are longer ones for a deeper reach into the meat of bigger specimens and slightly more streamlined versions for higher speed, but you still need to be close for the shot and have a reasonably powerful gun. Not too much power or you will dissipate energy in turbulence behind the pranger head.

Quote from silverspearo

Would you recommend brass or stainless screws? Which in teak I suppose you would need to drill a smaller hole to avoid the risk of splitting the wood?

Sent from my iPhone using Tapatalk

I use chrome plated brass, but now all our fasteners come from China these are hard to get here unless old stock. Stainless is OK, but it can corrode in the wood as oxygen is denied to the chrome and you can have rust form on the screw threads. May sound funny, but raw brass will be OK provided the brass is of good quality. When I drove the stainless steel mechanism holding pins out of that home-made gun they keyed out pieces of timber due to rust on the pins despite being heavily painted over with marine varnish. So stainless steel can be a liability despite its greater strength. That timber gun was made in 1976 and is equipped with a pranger head for close range shooting and non-escapees.

The Speardiver Reel has now appeared at post #2. Did I blink and miss this or has it just appeared? Anyway it looks a good solution if you can screw it onto the shooter, which I am sure you can do.

Another possibility is to buy a cheap moulded all-plastic fishing reel and cut off the rod attachment post flush with the edge of the reel. The reel is then affixed by two wood screws placed through the backing plate after dismantling the drum off the spindle and would probably fit under your shooter. Here is a home-made band gun using an "Academy" fishing reel in a drum mounting. I have shot plenty of fish with it and few have ever escaped.