Infinitengines "Dreamair" pneumatic speargun

[popgun pete]

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.

 

[popgun pete]

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. That is based on a batch being ordered, not one gun on its own.

 

[popgun pete]

New single barrel alloy gun in a carbon fiber hull.

 

[popgun pete]

Another view of the gun and the hand pump for pressurizing it at the start of the season.

 

[popgun pete]

Inner cable sweeps the interior as the inner drum winds in the piston, as shown in the sketch. The bore size of the barrel determines whether it has a free path without touching anything as it traverses the surface of the drum. The gun will be longer than the sketch image shows, but gives a general idea of how it needs to work.

 

[marco15499]

This is really unreal!

I wonder if the system is reliable to be used in remote locations without any needs of preventive (or corrective) maintenance. I really like the concept and the performance of this gun!

 

[Diving Gecko]

I think it will be fine in terms maintenance but ding the drums on a remote location and you may be in trouble.


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[popgun pete]

Another video. In this video we see the gun floating after the shot, tail down due to the reel. All carbon version of the "Dreamair".
Dentex Passion

Moment of hit.

In this next video the alloy internal barrel gun is shown in action, note the changing graph displayed on the left hand side of the screen as shots are taken at different ranges.

 

[popgun pete]

Apparently the inner drum is more of a cylinder in the third version, so its contribution to gearing is fixed in the single alloy barrel model. You would still have some gearing in the beehive shaped outer drums, but the advantage is less than with spiral track drums on both. One needs to remember that the shot is the loading effort replayed in reverse, hence provided you can cock the gun it does not really matter. On a standard pneumatic the compression ratio is about 1.10, so the force at latch is 10% greater. Might not sound much, but with pneumatic guns that are pumped right up that extra 10% can be an eye-popping effort with your arm in a position where you cannot apply much more grunt. If the gun had a constant pressure then loading would be easier, but that would require a massive air reservoir allowing the gun to have a compression ratio of 1.0. Now with the Dreamair you can offset that 10%, or part of it, by the gearing system offered by the spiral drums. That means you have a chance of loading it at higher pressures, so any gearing helps. In fact you really need it as the compression ratio is about 1.50, which is 50% more effort at latch.

The downside, if say you are comparing it to a multiple band gun, is that in effect you are loading all the bands at once, there is no splitting of the loading effort. That is why for higher pressure you need the Dreamloader, which stages your effort rather than splits it. Compressed air is a lot more efficient at energy storage than rubber bands, but losses in the drum and sliding piston system are unknown, although they should be low with some energy being required to spin the drums and axle.

The “Dreamair” is a big piston gun which would not be practical in a standard pneumatic gun layout with a wet barrel, but provides higher force levels thanks to that larger cross-sectional area facing the gun’s internal air pressure.

 

[popgun pete]

I inquired and the "Dreamair Unreal" does disassemble, even though it looks to be one-piece in the existing photos. Photos are going to be made available showing the sub-assemblies, so it will be interesting to see how the new gun goes together. Bar checking the inner cable and the oil there is not much need to go inside as water should never penetrate the gun. Some gas and oil might get past the piston seals into the vacuum area, but it can be purged using the rear valve.

 

[marco15499]

This doesn't stops to amaze me!

 

[popgun pete]

A few more photos. (taken by Stratis Gelagotis)

Note cable winding from the bottom of the drum.

 

[popgun pete]

A side view of the rear handle and butt.

 

[popgun pete]

Look who is coming to dinner.

Stratis Gelagotis with catch.

 

[marco15499]

I am really impressed with this speargun.

 

[popgun pete]

Bagging a Dentex.

 

[popgun pete]

I had hoped owners of the first batch of carbon and alloy inner tubing "Dreamair" guns might be posting about their guns by now, but a lack of any news seems to indicate that they have not received them yet or maybe only very recently and have had no chance to use them. Here summer has started, but the weather is very variable when cold winds blow up from Antarctica and I expect it is wintery in the northern hemisphere, so diving is out of season.

 

[popgun pete]

There is now a version of the "Dreamloader" which gives a 3:1 mechanical advantage by adding another set of pulleys on each side of the loader cables. The original "Dreamloader" with the pulleys in the wishbone hooks gives a 2:1 advantage. The loading handles need to pull three times the wishbone draw distance instead of twice the distance if you use the extra pulley sets.

 

[popgun pete]

The first guns with an aluminium tube inside the carbon fibre bodies have been delivered. Cost is 800 euro each for the first batch which includes hand pump and “Dreamloader”.

 

[Diving Gecko]

There is now a version of the "Dreamloader" which gives a 3:1 mechanical advantage by adding another set of pulleys on each side of the loader cables. The original "Dreamloader" with the pulleys in the wishbone hooks gives a 2:1 advantage. The loading handles need to pull three times the wishbone draw distance instead of twice the distance if you use the extra pulley sets.
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Thanks for the update Pete.

I actually had a 3:1 version of my PulleyLoader for my airgun under construction but turned out 2:1 was enough for my use. 3:1 would possibly give me a bit more control of the shaft during loading so I may still make it one day to test that.

I’ve said this a ton of times, I have so much respect for Andreas’ tenacity and don’t want to sound like a downer but I just have a bit of a hard time to see the positives in the DreamAir needing a loader and now, an even more powerful one at that. If I was really skeptical, I’d have to say it could point to the gun not being as powerful as he expected. But at least, it should show that the internals are well designed and built if he can power it up the much and the parts can take the beating.

Also, I made one for my own airgun as an alternative to a Mirage mechanism and while it’s an extra bit of kit that takes time rigging and storing, it’s not that big a deal on a big gun. Still a bit slower than a three banded classic gun but if you are already missing out on super fast reloading, I don’t think it matters if you’re 30-60 secs slower.

I would really like to see a proper Majd-style pool test to see how the gun shoots with and without the loader.


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