Could an irregular ...
 

Could an irregular shaped tank be used for HPA tank in a PCP?  

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NOVAir
(@novair)
Joined: 2 years ago
Posts: 18
2018-07-27 20:05:11  

As the title says:   Could an irregular shaped tank be used for HPA storage?   For example, instead of the Air Force style HPA bottle-shaped stock, the HPA tank would be shaped like a regular rifle stock.   Composition would be the same as any 4500psi+ paintball tank or PCP bottle tank. 

I assume that the irregular shape/jagged edges corners of such a stock would result in much higher psi pressure at those locations compared to a perfectly round shaped tank where the pressure is evenly spread out against the round walls.  Is that so?    How much more pressure would be at those points and would they result in a failure when using materials/design-structure of a normal HPA tank?

 


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Doug Wall
(@doug-wall)
Joined: 2 years ago
Posts: 111
2018-07-27 20:27:26  

Not a good idea. The cylindrical shape and, in some, rounded ends, are the strongest shape. The aluminum liners are also drawn/extruded from a single piece of metal. About the only way to shape something like a stock would be to weld pieces together, and I don't know how they would wind the carbon fiber around it. The flatish sides of a stock would be a weak point, and might bulge out.


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garczar88
(@garczar88)
Joined: 2 years ago
Posts: 44
2018-07-29 11:06:40  
Posted by: NOVAir

As the title says:   Could an irregular shaped tank be used for HPA storage?   For example, instead of the Air Force style HPA bottle-shaped stock, the HPA tank would be shaped like a regular rifle stock.   Composition would be the same as any 4500psi+ paintball tank or PCP bottle tank. 

I assume that the irregular shape/jagged edges corners of such a stock would result in much higher psi pressure at those locations compared to a perfectly round shaped tank where the pressure is evenly spread out against the round walls.  Is that so?    How much more pressure would be at those points and would they result in a failure when using materials/design-structure of a normal HPA tank?

 

Don't EVEN think about it. Pressure vessels are shaped they way are for a reason.


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awilde
(@alex-from-upstate-ny)
Joined: 2 years ago
Posts: 116
2018-07-29 11:20:32  

You could probably have a couple of smaller diameter mini tube tanks connected in series that simply slid inside a hollowed out stock (would still be somewhat limited as I believe they all need to be the same size for that kind of connection and would only fit but so many inside of a standard stock shape). Just my machinations for what they're worth.


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NOVAir
(@novair)
Joined: 2 years ago
Posts: 18
2018-07-29 12:55:00  
Posted by: garczar88
Posted by: NOVAir

As the title says:   Could an irregular shaped tank be used for HPA storage?   For example, instead of the Air Force style HPA bottle-shaped stock, the HPA tank would be shaped like a regular rifle stock.   Composition would be the same as any 4500psi+ paintball tank or PCP bottle tank. 

I assume that the irregular shape/jagged edges corners of such a stock would result in much higher psi pressure at those locations compared to a perfectly round shaped tank where the pressure is evenly spread out against the round walls.  Is that so?    How much more pressure would be at those points and would they result in a failure when using materials/design-structure of a normal HPA tank?

 

Don't EVEN think about it. Pressure vessels are shaped they way are for a reason.

Thank you for the reply and the warning, but a response such as yours is unhelpful on so  many levels that I am not even sure where to start.

 1.    I believe that my question was fairly clear that I hope to find an answer "in theory" ...as in "describing what is supposed to happen or be possible, usually with the implication that it does not in fact happen"

2.   You are implying without actually asking/knowing that I plan to implement this vs. wanted to shed more light on the reasons and limitations of vessel designs

3.  I let that possibility to go without taking offense that you may have assumed I would implement something potentially dangerous without getting all the facts and information first 

4.  Any answer that states "it cannot or should not be done because it was always done this way" or "there is a reason why it is always done this way"  shows a certain level of (sorry to say) ignorance. If people throughout history would have never questioned the conventional wisdom, we would be still be using rocks as tools inside a cave, would think the Earth is flat, and that the Moon cannot be reached by humans. 

Now back to my original question:  let's assume that there is an HPA tank that is shaped like a rifle stock and built with same materials as a 4500 psi carbon fiber tank (a paintball tank which has a burst pressure of about 7,500-10,000 psi).   Would you agree that it can be filled with 1 psi air?  What about 10 psi air?  What about 100psi?  And what if 1,000psi? 1,500psi? 2,000 psi?  4,000psi? etc.   Do you see my point?  At what point may there be a failure of such design vs. the conventional design that was designed to be operated up to 4500psi? 

I know that a specific and actionable answer cannot be found unless the specifics of the exact angles, thickness, materials, etc of the irregularly shaped tank is known.  But there should a point somewhere between 1psi and 4,500psi where to irregular tank CAN BE operated safely.

To illustrate this, I took some photos of my Impact tank showing that the conventional tank design (albeit no sharp edges) does allow for a 90 degree turn of the walls within a distance of half inch. Also, the other photo shows that there is a 90 degree turn in a matter of about 1 inch and a full 180 degree turn in 2 1/4 inches (the width of the tank). 

Without the mathematics and physics  genius of "Steve in NC" and probably countless hours of calculations/modeling there may not be a precise answer. But "in theory" there is a point where within the parameters of certain design limitations an irregularly shaped tank COULD BE incorporated inside a conventional rifle stock.  The question still remains: what would be the max. pressure limitation? 

IMG 9074
IMG 9075


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Doug Wall
(@doug-wall)
Joined: 2 years ago
Posts: 111
2018-07-29 14:50:47  

OK, since you don't seem to be understanding that a rifle stock shaped tank CAN'T be fabricated the same way as a cylindrical tank, here's a little experiment for you, Take a round, 2L soda bottle, and a rectangular 64 ox (1.89 L) juice bottle (simulating a flattish rifle stock). Blow into each one. The round soda bottle won't deform at all. The rectangular shaped juice bottle, will have the flat sides bulge out, and if you were to put a compressor on it, and pressurize it to say 100 psi, the bottle would bulge enough to approximate a cylinder. any flattish tank would do the same. Once the structural shape of a tank starts to deform, failure usually isn't too far behind. As has been said, don't bother trying.


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NOVAir
(@novair)
Joined: 2 years ago
Posts: 18
2018-07-29 16:44:18  

Thank you everyone for their inputs.  DomingoT, thank you very much for taking your time to highlight the major reasons why such irregular shape vessel may be impractical design-wise and economically.    I am sure this is not the first time such question was asked and most likely in each case the possible solution suggested high costs and a severely reduced utility for such vessels.

So  based on what "awilde" and you are pointing to as a the potentially easiest (a relative term) way,  is to have several tubes in parallel and arranged in close approximation to the shape of a traditional rifle stock.  I can see how such solution could be difficult and pricey to implement.  I attached a couple of photos of commercial boiler tubes, and one end of a boiler vessel with such tubes inside.  Of course the pressures inside these boilers are not even close to HPA levels (and do not require special materials and an intricate design). But in theory a rifle stock shape may be able to be formed, albeit the actual inside capacity could be quite limited.  

Still curious what the maximum pressure limitations of an irregularly shaped vessel may be.  One specific shape I would be interested in calculating is a vessel in the shape of a hip flask  that could slide inside the rifle stock.   But short of having some sort of a specific design already in public domain (as you noted) arriving to one would require some heavy-duty computing power with sophisticated modeling. 

Thank you again for your inputs.

stainless steel boiler tube 500x500
images (1)

1441435464 image59
monel pipes


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garczar88
(@garczar88)
Joined: 2 years ago
Posts: 44
2018-07-29 16:46:38  
Posted by: DomingoT

@NOVair,

Your question is excellent, and more profound that it looks.

What constraints the design of a high-pressure vessel (or a vessel subjected to external pressure, such as a submarine) are the stresses that can cause it to fail.  There are two kinds of stresses in a pressure vessel: tensile stresses and bending stresses. The combination of these two stresses is what may cause the vessel to fail.  Tensile stress happens when you pull something apart - these stresses are related to the size of the vessel. Bending stress happens when you bend something - these stresses are related to the curvature of the vessel walls.

A vessel of cylindrical shape has the enormous advantage that the material is subjected "almost" entirely to tensile stress. The moment the vessel is not cylindrical, bending stresses appear, making failure more likely unless the vessel has been carefully calculated. That is why non-circular shapes are avoided in airliners and gas tanks.

There is another, more pedestrian advantage to circular pressure vessels: They are easy to calculate - no need for fancy math. Designing a vessel of arbitrary shape, on the other hand, requires the use of specialized math and computational techniques (the theory that deals with this is known as "theory of shells").

Does this mean there are NO alternatives to the circular vessels? The answer is no. There are two alternatives that could be applied to airguns, but to my knowledge haven't been used so far.

One, mentioned by awilde, is a battery of circular skinny reservoirs connected in series or parallel, that you could fit in a conventional-looking stock.

Another alternative is the so-called "double-bubble" arrangement, where you have two cylinders that intercept, and where the lines of contact are held at constant distance by plane sheets. This idea was used successfully in some aircraft pressurized cabins.

Finally, to your main question: It is perfectly possible to design a pressure reservoir of unconventional shape that can be operated safely, but the calculations are complicated and the manufacturing is expensive.

Don't forget DOT approval. Nothing is impossible but at what cost? Hey, deHavilland thought that square airplane windows would be ok. How many died proving that little theory wrong?


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Hector J Medina G
(@hector-j-medina-g)
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Posts: 286
2018-07-29 16:54:51  

There seems to be a lack of knowledge about antique airguns history here.

A few centuries ago, some airguns were made with CONICAL reservoirs that also doubled as a "buttstock". Not exactly a flat sided modern buttstock, but at the time, even the buttstock was in evolution and different designers/builders used completely different approaches (chin stocks, chest stocks, over the shoulder stocks, etc.) The modern buttstock (shoulder supported, cheek rested, forearm holding) probably came into being about the 1700's

The Girandonis were, in a way, similar to the Talon, but different.

Those old guns, when handled are vastly superior in performance, balance, and ergonomics to their spherical reservoir counterparts (the other main design of the time).

The conical tank was made brazing a flat sheet into a cone, and then that cone brazed to a hemisphere on the large end, and to a valve/connection on the small end.

Could conical tanks be made with  modern technology? Yes, but the truth is that no one seems to be interested. Shot count is more important and a cone will hold only 1/3 of the volume of the circumscribed cylinder containing it.

Modern replicas are rated to about 1,500 PSI's, (the originals, charged to 800 PSI could fire 20 good shots: 800 fps with a 120 grains round ball), and are very interesting. Also expensive (like $34,000) because they are all handmade.

So, there is a somewhat positive answer to your very good question.

 

 

Keep well and shoot straight!

 

 

HM


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NOVAir
(@novair)
Joined: 2 years ago
Posts: 18
2018-07-29 17:05:41  
Posted by: garczar88

Don't forget DOT approval. Nothing is impossible but at what cost? Hey, deHavilland thought that square airplane windows would be ok. How many died proving that little theory wrong?

I agree with part of your statement:  "Nothing is impossible".      I lived by that motto during my previous life and it helped me overcome many adversities, tasks, and events when I and others could have easily just walked away from.  My motto in my signature block was:  "Only those who see the invisible can do the impossible!"

The way I approach things, if I am facing a challenge, is to investigate if it's even possible.  That means to think outside of the box and throw out conventional wisdom until proven wrong.   Determination on economies of scale comes later and is not the primary focus when seeking to solve a theoretical problem.   Albeit a huge stretch from HPA vessels:  getting humans on the Moon was an enormously expensive project with very little utility, but it was something that was eventually accomplished thanks to American ingenuity.   Obviously, the costs vs. benefits of regular adventures to the moon prevent such projects from continuing...


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NOVAir
(@novair)
Joined: 2 years ago
Posts: 18
2018-07-29 17:19:41  
Posted by: Hector J Medina G

There seems to be a lack of knowledge about antique airguns history here.

A few centuries ago, some airguns were made with CONICAL reservoirs that also doubled as a "buttstock". Not exactly a flat sided modern buttstock, but at the time, even the buttstock was in evolution and different designers/builders used completely different approaches (chin stocks, chest stocks, over the shoulder stocks, etc.) The modern buttstock (shoulder supported, cheek rested, forearm holding) probably came into being about the 1700's

The Girandonis were, in a way, similar to the Talon, but different.

Those old guns, when handled are vastly superior in performance, balance, and ergonomics to their spherical reservoir counterparts (the other main design of the time).

The conical tank was made brazing a flat sheet into a cone, and then that cone brazed to a hemisphere on the large end, and to a valve/connection on the small end.

Could conical tanks be made with  modern technology? Yes, but the truth is that no one seems to be interested. Shot count is more important and a cone will hold only 1/3 of the volume of the circumscribed cylinder containing it.

Modern replicas are rated to about 1,500 PSI's, (the originals, charged to 800 PSI could fire 20 good shots: 800 fps with a 120 grains round ball), and are very interesting. Also expensive (like $34,000) because they are all handmade.

So, there is a somewhat positive answer to your very good question.

 

 

Keep well and shoot straight!

 

 

HM

HM,  thank you for that nice piece of airgun history.   I actually posted on another airgun forum (are we allowed to link here?) about a month ago similar pictures of antique airguns.  I will copy and paste some of the photos that really amazed me about how similar airgunning was back in the days but also how much airgunning has evolved thanks to non-stop innovation and thinking outside the box.  But before you look at those photos here is on that may baffle the mind and it illustrates the point of thinking outside the box.  This air pistol by FWB actually worked and was quite accurate according to what's written below.

From Beemansnet.com:

” After one of the big SHOT trade shows, the owners of the Westinger & Altenburger Co. (Feinwerkbau) of Germany presented us with this amazing feat of airgunsmithing – a Beeman/Feinwerkbau Model 2 CO2 pistol with the barrel making a complete twist around the gas cylinder! The gun actually shoots quite well! Note that the all-important final inch(25 mm) or so is straight – that and the crown are the only really important parts of the barrel as far as accuracy is concerned. When some shooter would say ” I think I see some little defect in the rifling way down inside my barrel, or the middle is a little off, or the barrel is not quite straight, and that is why I am not shooting well” , the airgunsmiths loved to bring out this gun and ask if his gun was more off line than this one! Beeman collection.”

Here are the rest:

https://www.beemans.net/Austrian%20airguns.htm

  https://www.beemans.net/lewis-assault-rifle.htm  

https://www.beemans.net/collection.htm

1529009120 14358991525b22d3e08c9a98.57063741 1197
1529009129 18236291875b22d3e9961e30.54333211 1344
1529009180 20194907905b22d41c5aae47.73661964 c3c5c5302cb1f6ae39119259bbbd442a
1529009783 407872515b22d677f0a6e5.59446989 BGR balls 9k
1529009802 6249947385b22d68ac94c56.65648261 Gir left
1529009970 4555030755b22d7327580e0.08313650 RA 6  Austrian Partisan Det
1529010013 9053076435b22d75d0ee956.27101661 e6a14e43c302c6928f955354a529dfa9  flintlock pistol steampunk weapons
1529009929 18108306235b22d7092ddef4.23698663 RA5  Austrian Partisan Airg
1529010505 18391728855b22d9493893a6.86193920 584a42549e3a7ba719686b22011c8d4d
1529010505 18391728855b22d9493893a6.86193920 584a42549e3a7ba719686b22011c8d4d (1)
1529009770 10449771655b22d66a871220.78366146 BG reservoir RH 19k


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Hector J Medina G
(@hector-j-medina-g)
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2018-07-31 06:27:28  

NovAir,

Those that have known me for some time know that I have had an excellent relationship with DIANA (Mayer and Grammelspacher).

M&G's seat of business was Rastatt, an "Imperial City" since very old times. At the museum in Rastatt there is one of the very few remaining pristine examples of a Girandoni military rifle, as well as some other excellent airguns of the spherical reservoir design.

As is normal when a company has been in operation over 120 years in a city, there was "perks" to being an official invitee. One of them was a private viewing of the Imperial Museum's airguns. That's how I know first hand the difference in ergonomics and handling of the two different systems. The spherical reservoir is heavy and clumsy, felling like a 2" x 4". The Girandoni comes up to shoulder, shoulders, and points, like a modern carbine, even with  its long barrel. Naturally, it's all about the balance.

Performance wise, other museums report that spherical reservoir rifles yield 4 to 5 shots, clearly inferior to the Girandoni's 20.

Fast forward to modern times and we are now working with DIANA on a coaxial (I wouldn't call it concentric) design where the tank surrounds the barrel. Problem there is that, to have a useful shot count,  the assembly needs to be long, and it doesn't have the balance and nimbleness of handling we would like. But we are working on it.

Someone once said that those that don't know History are doomed to repeat it. I prefer to take a more positive attitude and think that when history was young there were much less naysayers and pessimists.

Before thinking "outside the box" it behooves us to know how big really the box is.

😉

 

Keep well and shoot straight!

 

HM


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NOVAir
(@novair)
Joined: 2 years ago
Posts: 18
2018-07-31 14:25:06  

HM,

Thanks for sharing the Diana company background information and the museum experience.  My second springer (in the 90's) was the RWS-54 (before I went to the darkside).  It is/was an amazing piece of machinery and innovation in my opinion with the recoilless feature.   A bit heavy but was a pleasure to shoot.   I wish they had JSBs back in those days (I wasn't aware of them). 

Having a Girandoni back in those days must have been a high-tech endeavour for the times.  Your post about it prompted me to dig up some information about them. It's impressive to have so many lethal shots (about 20) with such heavy balls (140 grn)  at  120-150 meters distances.  The design limitations of those times (based on the info) required extensive training by the soldiers, extra care and maintenance for the reservoirs, and compex manufacturing of the parts. These factors eventually led to their discontinuation.

Like you said, now comes 2018, and two centuries worth of innovations which may open up previously visited airgun areas for new development.  As you mentioned Diana along with experts is looking into a "coaxial" type barrel/tank setup. I assume that the reservoir would be completely around most of the barrel.  It seems one the benefit would be better sound suppression.  As far a more capacity, did you consider an offset tank/barrel design similar to the Edgun Leshiy moderator/barrel? (see attached)   The wider part could be facing towards the ground.

s408647811433489150 p18 i6 w160
s408647811433489150 p40 i1 w640

 

 

airgun 920x431


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Citizen K
(@citizen-k)
Administrator
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2018-07-31 14:50:33  

@hector-j-medina-g

I assume the Diana effort will be trying to "fix" the Artemis M30 design?  https://www.airrifle.co.za/threads/47392-SPA-Artemis-M30

 

Forum Janitorial Services Specialist


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Hector J Medina G
(@hector-j-medina-g)
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2018-08-01 06:08:05  

NovAir,

It would be an interesting idea, but the offset parts would add much cost that would translate into a high price.

Sound suppressors can use 3D printed parts. HPA tanks can't.  Maybe one day when we can print Steel or Titanium directly. That is about 5 years in the future, so it could come.

CitizenK,

You are partially right, yes, that is where we're starting from, but it's not a "fix". The rifle, as is, works very well. It just doesn't HANDLE well and looks a bit like an Aardvark.

Shortening the barrelled action and using a different Stock it can look like a Delisle Carbine. Making the reservoir a little slimmer and with little changes in the action and you have something like a sporterized Small ring Mauser or Springfield. Equip it with an externally adjustable scope and you have an early ScharfSchützen Gewehr.

😉

With current technologies we're finding it is better all around to use higher fill pressures than to use very large tanks.

Thanks for your very accurate comment.

Keep well and shoot straight!

 

HM


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Gratewhitehuntr
(@gratewhitehuntr)
Joined: 2 years ago
Posts: 263
2018-08-01 07:48:43  

The last time I asked a question about limitations (what is the highest pressure successfully used in a pcp?) it resulted in a thread full of heckling.

Specifically Dan House and Steve NC. I lost a lot of respect for both of them, and the Yellow that day.

 

Glad to see that you are doing better, and the answers have been useful to read.

 

Here is a bit of reading, you really only have to read item #1, then check below for the * associated with #1

It should clarify why cylinders are skinny, why the move away from integral, and why 3D printing a buttstock around the cylinder is no-go.

 

https://www.law.cornell.edu/cfr/text/49/180.209

 

 

Re-edit.

When someone tells me things "Have been that way a long time" I assume that they are too lazy, or lack required intelligence, to change anything. Keep thinking, it's what dragged humans out of the mud.

Remember, you don't have to run faster than mud, just walk slowly away from the guy who thinks mud is the pinnacle of human tech.

( a bear joke)

There you have it, the world according to John.


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NOVAir
(@novair)
Joined: 2 years ago
Posts: 18
2018-08-06 01:35:14  

HM,  

Looking at the Artemis M-30 design and you mentioning the Delisle Carbine....may be moving the entire barrel/tank all the way to the rear as in a bullpup configuration could address the center of gravity and balance/handling issue.   With that however the traditional lines are lost unless there is a creative way to shape the stock around it.   

But, with moving the entire barrel/tank to the rear the opportunity presents itself to widen the tank in the rear area in a sort of a triangle shape since it's hidden by the stock around it.   Similar to the antique stock-tank posted previously.

Or shape half of the tank like the tank/stock in the antique rifle and connect the other part of the tank/barrel to it at an angle like in the antique rifle.  

 

 

Gratewhitehuntr,  thanks for posting the DOT info:                                                               

 "1 Any cylinder not exceeding 2 inches outside diameter and less than 2 feet in length is excepted from volumetric expansion test."

Unless there are other rules applicable here, I see the issue here. If the tank exceeds these dimensions it has to be able to be tested and removed for testing.  With two separate (not exceeding the specs individually) but interconnected tanks joined at an angle to form a "stock" and "action" this requirement  may be by-passed(?)

 

 

1529009770 10449771655b22d66a871220.78366146 BG reservoir RH 19k
1529010505 18391728855b22d9493893a6.86193920 584a42549e3a7ba719686b22011c8d4d

 


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garczar88
(@garczar88)
Joined: 2 years ago
Posts: 44
2018-08-06 08:21:43  

As for the Giradoni, what i was able to search out was it shot 210gr., 46cal. ball at 500fps. Also, what does "30 shots at useful pressure" really mean? From that size of tank 10-15 full power shots would have been quite respectable. I've seen one of the copies at a show and was blown away by the design and features.


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boscoebrea
(@boscoebrea)
Joined: 2 years ago
Posts: 174
2018-08-06 21:55:39  

Wow that was fun!Glad I listened ,learning is such turn-on.

 


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Hector J Medina G
(@hector-j-medina-g)
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2018-08-07 11:01:45  

NovAir.- Again, it is a question of a combination of factors. Design-wise and engineering-wise, everything is possible (at a price), but some things (like the Edsel) are way ahead of their time, if the market does not like the idea, you have a flash in the pan that is quickly discontinued. No sense going there.

Of course a few knowledgeable shooters will appreciate the effort and the engineering prowess, but the market right now seems to be pointing to the $2-$400 PCP's Making a two part air reservoir was tried by Logun with the Gladiator and the market did not accept the price difference, even with the very smart swing over two cylinders magazines. So it was discontinued. And other great airguns have been discontinued for lack of sales even with excellent engineering and manufacturing. Think of the P-H Phoenix, or the Whiscombe, the Firebird, or many others.

Here is not the place to discuss in detail the difficulties of making a firing mechanism act through pressurized vessels, it is a technology all of its own, as are the airways that allow guns like the M-30 to be regulated AND to have the TWO manometers, plus a well functioning valve, suffice to say here that adding complications to an already reasonably good design invites commercial disaster.

Garczar88.- I don't know where you read that about the Girandoni (210 grs @ 500 fps), but you should not believe everything you read on the internet without a modicum of research and sanity checks. Look up the weight of the ROUND BALL in 0.46" cal (the military caliber issue of choice by the Austrian Army), and then compare what I am saying to what you said you read somewhere; to make it easy for you, here is a link to the standard weights of round balls.

The surviving documents in the Austrian Army archives call for a gun capable of firing 20 accurate shots at a human torso sized target from 300 yards, which gives you a trajectory and wind drift "window" you need to attain, and where the 800 fps comes from. Back in those days, there were no Chronographs and the ballistic pendulum, that had been invented about 100 years before the Napoleonic wars was so expensive to use that only large artillery factories, or state arsenals, could use it. In the case of Girandoni, he was a small entrepreneur and worked over designs by Lukens, and by creating a TIMING valve was able to comply with the Austrian Army's specs with a repeater that could hold 20 round balls in the tubular magazine.

To all: Since we are talking of the Lukens, here is an exquisitely executed modern muzzle loading replica, I am sure the stock will be more to the liking of the traditionalists, and there is no magazine nor shuttle. it does have a "false flintlock holder" not only for looks, but to act as the hammer cocking mechanism. It is a great gun:

Back to history: There is evidence of a "crew serving" horse driven pump that was a carriage, but when turned over was a pump that would pump up 8 reservoirs at a time, ideally, a carriage for every platoon, should have kept the whole platoon firing indefinitely, if the men timed their firings to about double the rate of fire of the muzzle-loading muskets of the time (smoothbore). Those were limited in their accuracy (same torso sized target) to about 60-75 yrds and would foul up badly enough after 25 to 50 shots of government issued ammunition to make them impossible to load (hence the need for a bayonet), so, in theory, a well disciplined platoon of Girandoni equipped soldiers could have held at bay a whole regiment of enemies (and they did in several occasions).

There is a LOT to consider when designing an airgun if we want that airgun to be in production for many years to come.

History teaches us that it is not only brilliant engineering what takes the field.

My conclusion to this is that no one should ever be discouraged about new ideas, some new ideas are actually quite old. And nothing ever got done without someone actually driving the idea. It may need time, and money, and taking risks, but heck, it is YOUR idea and you should do every possible effort to bring it to fruition.

Good luck and keep us posted!

 

 

 

 

HM


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Bean
 Bean
(@steeve11)
Joined: 2 years ago
Posts: 17
2018-08-07 20:41:02  

My 2 cents as a successful, "outside the box" Engineer;  Future air gun design efficiency improvements will come from better valve designs and increased reservoir pressures.   First, you can't ignore the cost, weight and size limitations;  we have to be reasonable about what we can afford and carry around.  That is why there is no better shape for a high pressure air gun reservoir than a cylinder, when you consider cost, weight and a shape that lends itself to air gun ergonomics.   A "random" shape reservoir with "flatish" sections will only match a cylinder's capabilities if the wall thickness is increased dramatically, resulting in prohibitive weight and size; how would you like a conventional looking gun stock, but larger, that weighed 75 pounds made of half inch thick steel? That's roughly what you would need to hold 500cc of air, safely rated for 3,000 PSI.  The cylinder is the lightest, easiest/cheapest design, for high pressure air....it is a step backwards to use the low pressure vessels, as once used on the antique guns.... those guns used a much more complex and costly valve system in order to make efficient use of the lower pressure air, and even then, were no match for today's PCP in reliability, cost or performance.   Modern, high pressure air guns are co-evolving with the new generation of inexpensive HPA compressors; costs and efficiencies of both are improving, along with the increasing demand, and in fact are spurring demand.  I believe that from here, air cylinder pressures will increase, pressure regulators will proliferate,  and HPA compressors will continue to get better & cheaper.  In the higher end guns, more efficient PCP valve designs will replace the standard hammer & poppet types which will probably remain the standard only because of their low cost and simplicity.  

Regarding the twice mentioned reference to the manned Moon flight;  We still do not and may never get the technology to land and return a human, alive, from the moon.  That is a far bigger problem than most people realize.  It is far easier to perpetrate the hoax.  


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Bean
 Bean
(@steeve11)
Joined: 2 years ago
Posts: 17
2018-08-07 22:51:56  

Yes, we all, (who pay US  taxes), contributed to the NASA efforts....whether we wanted to or not. Our government would never think of lying to it's citizens, would they?  If you would like to discuss it further, PM me or email.  I am now retired and have plenty of time to talk about it.  Otherwise It could easily clog up this thread and get it shut down.


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