Infinitengines "Dreamair" pneumatic speargun

[Diving Gecko]

I don’t know what you mean about parachute. If you mean a cone, then a spearo who has done a lot more testing than most of us has shown that cones improve accuracy and penetration. If you are referring to a big slider then that’s exactly why I started my searched for small sliders long ago.
Finally, I don’t take much of what any of they italian brands say as gospel. Least of all Omer. On that same note, I suspect they say max. 30 bar and that would make sense with an 11mm barrel. My One Air is at 29bar and it’s basically the same gun.


Sent from my iPhone using Tapatalk

 

[ECK]

Yes, I mean the bad Slaider. + bad flopper = parachute.

I use my design.

This is so far the best. But there is an idea to tie the Shaft tail without Slaider

 

[popgun pete]

Iron logic!
Cavitation will not produce destruction.
But let's look with a different eye. OMER makes a recommendation on the Airbalete = 30bar and on Spear wears a parachute.
If you press the gas with one foot in your car, and apply the brake with the other. What will happen to the car?

When you make statements it pays to research your facts. https://ittc.info/media/5866/volume-ii-specialist-committee-on-cepahphss.pdf
Howver as DG says spears and spearguns don't enter this problem area.

 

[tromic]

Yes, I mean the bad Slaider. + bad flopper = parachute.

I use my design.

This is so far the best. But there is an idea to tie the Shaft tail without Slaider

Sergei, this is nice, hydrodynamic, but there would be hammering on the back end of the slider and at the front end of the cone tail end.
I am curious about your idea to tie the shaft without slider.. I have some ideas too but not very practical for usage.

 

[ECK]

Мои извенения. Я сделал фото без полиуретанового рукава.

Так и должно быть.

 

[ECK]

tromic : I am curious about your idea to tie the shaft without slider.. I have some ideas too but not very practical for usage.



Tomislav! This is a "bare" idea, made only drawings. Need a test.​

 

[popgun pete]

Some new material which has just appeared.

 

[popgun pete]

And more of the gun itself.

 

[popgun pete]

Well now we know the side tanks are just that and it is not like the three chamber extrusion that was proposed for the alloy version of the "Dreamair" gun. As the central tank has the sliding piston it must have some surface treatment to provide a suitable surface for the piston seals. The side tanks just hold air and nothing slides inside them. The outer hull is a jacket integrated with the handle and butt and providing the muzzle which mounts the winding drums and axle.

A lot of work involved in putting one of these together, I wonder how much is permanently bonded and which parts can be disassembled. Over a period access would be needed to the piston and possibly the inner cable with its tensioning element.

Answer just received is that the gun body is a Monobloc, but you can still access the internal moving parts. Looking at the trigger finger guard area the silverly cylinder must be the depressurization valve if any compressed air leaks into the area at the rear of the piston which will be under a vacuum when the gun is cocked to shoot. A loss of vacuum would not normally happen, but the valve was discussed earlier in this thread and acts as a check on the piston seals not letting air past.

 

[popgun pete]

If like me you have been wondering what the round object is on top of the "Dreamair Unreal" gun's rear butt it is a horizontal pulley that can anchor the Dreamloader cable as shown below.

 

[popgun pete]

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.

 

[Diving Gecko]

Thought I'd asked this already, but guess it didn't get posted (bad internet where I am).
Given that the rear attachment point is now a pulley would you get a better purchase if you only pulled on one handle (3:1)? Maybe at the very end of the loading "stroke" this could be an option.

 

[popgun pete]

I think the knots being ordered in pairs are intended to pull the wishbone evenly from side to side and would be a problem going around the rear pulley if you only pulled on one handle instead of two. Plus the mechanical advantage of one pulley hook would be lost. The only time consuming aspect is sliding the handles up to and catching them onto the next knot which I guess would improve with practice. The Dreamloader would be handy on an inverted rollergun as you are pulling against pre-tensioned bands from the start, although you have the sub or side-pulleys to help lower that effort.

 

[Diving Gecko]

I think the knots being ordered in pairs are intended to pull the wishbone evenly from side to side and would be a problem going around the rear pulley if you only pulled on one handle instead of two. Plus the mechanical advantage of one pulley hook would be lost. The only time consuming aspect is sliding the handles up to and catching them onto the next knot which I guess would improve with practice. The Dreamloader would be handy on an inverted rollergun as you are pulling against pre-tensioned bands from the start, although you have the sub or side-pulleys to help lower that effort.

I guess you have to pull the knots over the pulleys at the front, too but perhaps the "loading pad pulley" is not big enough to let them pass.
You know my thoughts on why I think the Dreamloader has seen the day of light, but others will have to judge for themselves whether it is too big a hassle.

I thought of something else and as often is the case with me on this thread, it's pure speculation. But I see that Andreas says the barrel are "CNC" and "filament wound". Simply told, instead of hand laying CF laminate onto a mandrel it is done by a robotic arm. Think of a "lathe" turning the mandrel while the robot arm travels back and forth laying up a narrow strip of unidirectional, continuous CF fiber - which has just passed through a vat of epoxy resin. Now, that's actually a quite specialized process and much more advanced than just laying up sheets of prepreg onto a mandrel for tubes. As such, it's probably not a cheap way of manufacturing at all. But... like a lot of other things CNC, filament winding has had a few "people projects" already harvesting the cheap technology that is now abundant in terms of CNC controllers, stepper motors and such. One guy did a kickstarter project and now sells a filament winder for the DIY (perhaps called X-winder) but at least one or two other guys have made one themselves from scratch. The hardware is fairly simple, the main challenge on that side is likely the articulating head and the resin bath roller squeegees - but I suspect the real challenge is the software. But what I am speculating is that Andreas or a buddy of his may actually have built their own winder for just a few hundred Euros ... Either that or I truly hope they have a friend with a pro facility where they don't have to pay the going rate...

[EDIT] Ah! I hadn't looked into filament winders for a few years but just had another peek now and here's a more recent DIY project:

Carbon Framebuilding: Die Faserwickelmaschine

Today I’m switching gears from cross-continent trips to my further experiments in carbon fiber framebuilding. I’ve spent the second half of this year bumbling my way through the first q…

bryanmkevan.bike

 

[popgun pete]

The two flanking side tubes are tapered to fit into a tapered outer gun body, sort of like tapered fishing rods, but without the narrow taper to a tip. I have never really thought about how fishing rods are made out of carbon fiber, but some sort of winding motion must create them in order to have seamless tubes. Earlier fiberglass fishing rods were solid core, however that technology was ditched many decades ago as such rods were heavy.

Just thinking about it some more I would expect that masts and spars for yachting are probably a big user of hollow carbon fiber composites.

Carbon Fibre Yacht Masts, Pauger Australia Tempo Spars

 

[Diving Gecko]

Mast and booms are often hand laid up on a mandrel using patches of prepreg, bagged and then cured in an auto clave (though sometimes, and perhaps more and more lately, they are made in molds). I think a lot of fishing rods and golf clubs are hand laid up a bit the same. But i guess since the mandrel is much smaller, they can roll the prepreg sheets onto the mandrel. I have seen it being called "roll wrapping" in a few places. After being laid up with fabric, the laminated mandrel is wrapped with a heat shrink tape for curing and placed in an oven.
Now, when "filament winding" is mentioned it is specifically about winding the CF tow (narrow strip of continuous fibers) onto a turning mandrel. It is not laying up sheets or patches of CF fabric onto a mandrel like described above. Filament winding needs more complex CNC machinery than roll wrapping which can be done much more manually. Now, why Andreas designed his inner reservoirs to need winding instead of a simpler method, I don't know. But he has proved an affinity for taking the difficult path more than once

 

[ECK]

Is there water inside the gun? What do you think?

 

[popgun pete]

Is there water inside the gun? What do you think?

There is no water inside the gun except around the trigger mechanism, all the other spaces are sealed. The separate tubes are bonded together by the gun outer jacket so that the final stock is one-piece with no gaps.

 

[popgun pete]

Another fish skewered over a rocky bottom.

Note that in the video the drive cable is again winding from the bottom of the drums. I think this stops the drive cable from flopping over the end of the muzzle if it was wound the other way after a shot, there being no wishbone catcher.

 

[Diving Gecko]

Looking at the latest video, I slow mo'ed it to check the recoil in detail. I have recently shot my Evo in the pool at 30bar (8mm, 145cm shaft) and with that shaft the gun has some proper recoil and I could see the Dreamair was not too far of, so it must really be powered up and almost certainly loaded with the pulley loader. But to be sure, I asked Andreas and he already replied:

"Yes Dreamair Unreal was loaded with the Dreamloader whith pulley at 19atm or 95Kgf on the piston. The piston has an area of 500mm2."