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Infinitengines "Dreamair" pneumatic speargun
- Thread starterpopgun pete
- Start date
Thread Status: Hello
, There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.
It can take a long time to get an up-to-date response or contact with relevant users.
You can see the target in the distance being hit and moving with the shaft impacts. The shaft flies very quickly and there seems to be little recoil as the "Dreamair" gun shoots. I think that the multitude of shots shown indicates that the gun works reliably and consistently which is what you want in a speargun. Considering the technical challenges that had to be overcome, and I had my doubts earlier due to the attention to detail required to make everything work, I think the gun is a great achievement.
I take my hat off, pretty amazing what they have accomplished so far. I really appreciate the attention to detail and quality. I can't wait to see more videos to get an idea about accuracy.
At the end of the footage it seems like the target is 6m away if the bobbers are spaced 1meter which is likely.
If it is accurate at that distance it is going to attract a lot attention.
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At the end of the footage it seems like the target is 6m away if the bobbers are spaced 1meter which is likely.
If it is accurate at that distance it is going to attract a lot attention.
Sent from my iPhone using Tapatalk
Here is the version with the pulley built into the hooks; the metal ring attaches to the shaft as a fixed anchor point that you can then pull against as you haul the wishbone(s) back. Doubling the line at the hook pulleys halves the pull effort, but you have to pull twice as far which is what you expect to do with a "block and tackle" device. A very ingenious design!
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The only current video is the one showing the gun being shot at an underwater target, but at the start you can see the gun being charged and it appears to happen with two separate draws of the loading device. The knots may trap the line once they pass through the rollers built into the hook bodies and thus create a "one-way" action for the operator to then take that second draw and complete loading to the shaft's rear wishbone notch or tab. That would explain the second draw after pushing the cylindrical grip handles forwards under or over the outer cables, in fact you can see the operator wiggling the black grip handles forwards along the gun body.
The "Dreamair" speargun should be more efficient than a band gun as its "pneumatic spring" energy storage will be more efficient than using stretched rubber bands as an energy storage medium. Also the effects of "band soak" mean that the longer a band gun is cocked then the force available for shooting decreases from that which was required to cock each band in the first place, however the loss is not great and we don't generally notice it.
The big bore pneumatic speargun has always been problematic as water around the spear has to be pushed out of the gun which slows down the shot. In a hydropneumatic speargun this water braking effect is used to push the spear out of the gun because in a sense it is an extended barrel pneumatic speargun where the speargun has a big diameter (annular) piston that shoots backwards and the moving water is driven in the opposite direction by doing a 180 degree turn down a narrower ID barrel extension that actually holds the spear. These guns gain their performance by using very high start pressures, up to 3 times that used in pneumatic spearguns. Efficiency is not their strong point!
The "Dreamair" has a very big sliding oval shaped piston, so has a lot of force to play with (Force equals Gun Pressure x Cross-Sectional Area) and thus can power other moving elements (drums and cables) besides the spear and still provide good shooting performance. Also, unlike all other pneumatic spearguns, it will not be affected by increased ambient pressure at depth as the pneumatic energy storage system is completely sealed off from the environment. Although the cable drive system seems incongruous at first, it is the only way to use a big piston pneumatic speargun as the spinning winding drum axle is the only element that crosses the gun's pressure boundary. Like a balanced scuba regulator valve each end of the axle sees exactly the same pressure, which is ambient pressure.
The big bore pneumatic speargun has always been problematic as water around the spear has to be pushed out of the gun which slows down the shot. In a hydropneumatic speargun this water braking effect is used to push the spear out of the gun because in a sense it is an extended barrel pneumatic speargun where the speargun has a big diameter (annular) piston that shoots backwards and the moving water is driven in the opposite direction by doing a 180 degree turn down a narrower ID barrel extension that actually holds the spear. These guns gain their performance by using very high start pressures, up to 3 times that used in pneumatic spearguns. Efficiency is not their strong point!
The "Dreamair" has a very big sliding oval shaped piston, so has a lot of force to play with (Force equals Gun Pressure x Cross-Sectional Area) and thus can power other moving elements (drums and cables) besides the spear and still provide good shooting performance. Also, unlike all other pneumatic spearguns, it will not be affected by increased ambient pressure at depth as the pneumatic energy storage system is completely sealed off from the environment. Although the cable drive system seems incongruous at first, it is the only way to use a big piston pneumatic speargun as the spinning winding drum axle is the only element that crosses the gun's pressure boundary. Like a balanced scuba regulator valve each end of the axle sees exactly the same pressure, which is ambient pressure.
I suggest that if you want to keep tabs on when the "Dreamair" speargun will go on sale then you should periodically check the website set up for it.
http://www.infinitengines.com/
Right now there is nothing there, but when the gun is released it will be used as not everyone has a Facebook account, which is where the current info mostly comes from.
https://www.facebook.com/infinitengines/?fref=ts
http://www.infinitengines.com/
Right now there is nothing there, but when the gun is released it will be used as not everyone has a Facebook account, which is where the current info mostly comes from.
https://www.facebook.com/infinitengines/?fref=ts
Four cross-sectioned views of the "Dreamair" show its internal layout and the compact arrangement of the winding drums, axle, bearings and seals.
Note that these views are looking at the gun with it turned upside down as the inlet valve opening is underneath the muzzle. The shaft guide track is facing downwards and thus out of sight.
Note that these views are looking at the gun with it turned upside down as the inlet valve opening is underneath the muzzle. The shaft guide track is facing downwards and thus out of sight.
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Here you can see the spiral cable tracks on the winding drums, the housings for the spinning axle roller bearings and seals are screwed into the gun body, hence the screw threads on their surfaces. The "window" in the inner drum is the inner cable attachment point. The varying leverage or CVT aspect is obtained from the ratio of the drum diameters at the various points on their surfaces where the cables are simultaneously pulling or being pulled.
During transport I think that the outer drums would need to be protected against damage, so no stowing the gun in the car boot and then dropping a weight belt on top of it. I expect that a carry bag will be available and maybe a "gundom" protective cover, the latter being neoprene zippered bags that closely fit the stock at the front. I have a couple of these for my latest euroguns.
During transport I think that the outer drums would need to be protected against damage, so no stowing the gun in the car boot and then dropping a weight belt on top of it. I expect that a carry bag will be available and maybe a "gundom" protective cover, the latter being neoprene zippered bags that closely fit the stock at the front. I have a couple of these for my latest euroguns.
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Latest photo of a "Dreamair" gun down at the beach, so maybe not long to go now. This is a sample of the production model.
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I would love to see this system being tested for range, accuracy and recoil. It is so unique I find it very intriguing.
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
Just to clarify how the cables travel on the drums during the shot, black marks the start positions. During loading the cables reverse this movement, thus as one set of drums wind on the other winds off or vice versa. The "Dreamair" speargun is essentially a pneumatically powered high speed winch for launching the spear with the operator re-compressing the air storage system for the next shot via their manual loading effort.
Compressed air energy storage is much more efficient than using stretched rubber bands which suffer loss during "band soak" in their loaded up state.
Compressed air energy storage is much more efficient than using stretched rubber bands which suffer loss during "band soak" in their loaded up state.
This is a photo of the outer cables fully wound on the outer drums, the actual wishbone being a separate cord tied onto the end loops on the outer cables on each side.
I have been told that the website http://www.infinitengines.com/ will function like an e-shop at the time of the "Dreamair" gun's release. There is no content currently showing on that website, but something should be happening there once the northern hemisphere spearfishing season gets underway.
Nothing further to report, I recently asked and was told there would be more news soon, that was about a week ago. Checking the "infinitengines" website, which is to act as an "e-shop", shows that it has not been activated. Being summer I thought some guns might have become available.