Compressed air powered repeating crossbow idea, input needed.

[AnthonyCumia]

I would like to know if their is any reason why it has not been done.

Any legal issues I would need to be aware of?

Any mechanical reason why this is not possible?

[elephant]

I am in the hydraulic industry. I see a couple of problems. Air supply- is the crossbow permanently hooked up to a constant air supply line? Or does it have an onboard air tank? If on board tank, how much air volume? If your going to be using a pneumatic system to pull the bow string back into firing position and place a bolt/arrow into the ready position you would need a pneumatic power system that can repeat several times without loosing pressure- much like a paintball gun or air powered pellet gun. It can only work for so long until it has exhausted all of its stored power. Hypothetically, if your crossbow is constantly being supplied compressed air via air compressor, then it could work for the amount of bolts/arrows you have. But you are limited to the amount of air line you have. Having said that, how much force does it take to pull the string on the crossbow back the total distance? What ever that number is, you would need a pneumatic air cylinder with greater force, and to get that force you would need to either have (a) a large bore air cylinder or (b) high pressure air cylinder. Weight could be an issue, most pneumatic cylinders are aluminum though. A self loading crossbow mechanism, a guess it would be some type of gravity fed device that would have an interrupter to allow only one arrow to be inserted at a time. - I don't see that as being a barrier. Then you would need a pneumatic manifold, and a spring loaded 3 position valve that would work via the trigger, or you could have a small 6v system and have solenoid valves. I can see it being done, but not a hand held crossbow, it would resemble a smaller high tech version of Leonardo DiVinci's infantry powered auto/self loading crossbow contraption.

[SteyrAUG]

Arrow magazine.

Works only in the movies. Recocking isn't the problem, it's reliably feeding arrows.

[Moose-Knuckle]

Arrow magazine.

Works only in the movies. Recocking isn't the problem, it's reliably feeding arrows.

With your knowledge of ancient Chinese weapons, does this also plague the Chinese repeating crossbows of old? IIRC they had a gravity fed magazine on top like a Gatling, but instead of a crank they had a pump lever.

[JC5188]

With your knowledge of ancient Chinese weapons, does this also plague the Chinese repeating crossbows of old? IIRC they had a gravity fed magazine on top like a Gatling, but instead of a crank they had a pump lever.

Not only that, but the amount of air required for a "hi-cap" mag. The only way to concealed carry is to dress like an old lady with emphysema (tank dragger).

Just a range toy otherwise. :/


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[AnthonyCumia]

I am in the hydraulic industry. I see a couple of problems. Air supply- is the crossbow permanently hooked up to a constant air supply line? Or does it have an onboard air tank? If on board tank, how much air volume? If your going to be using a pneumatic system to pull the bow string back into firing position and place a bolt/arrow into the ready position you would need a pneumatic power system that can repeat several times without loosing pressure- much like a paintball gun or air powered pellet gun. It can only work for so long until it has exhausted all of its stored power. Hypothetically, if your crossbow is constantly being supplied compressed air via air compressor, then it could work for the amount of bolts/arrows you have. But you are limited to the amount of air line you have. Having said that, how much force does it take to pull the string on the crossbow back the total distance? What ever that number is, you would need a pneumatic air cylinder with greater force, and to get that force you would need to either have (a) a large bore air cylinder or (b) high pressure air cylinder. Weight could be an issue, most pneumatic cylinders are aluminum though. A self loading crossbow mechanism, a guess it would be some type of gravity fed device that would have an interrupter to allow only one arrow to be inserted at a time. - I don't see that as being a barrier. Then you would need a pneumatic manifold, and a spring loaded 3 position valve that would work via the trigger, or you could have a small 6v system and have solenoid valves. I can see it being done, but not a hand held crossbow, it would resemble a smaller high tech version of Leonardo DiVinci's infantry powered auto/self loading crossbow contraption.

I would be using the power of the gas itself and not a bow string. So I guess its not a "true crossbow".

I think a rotary mag might be doable but I did think of a gravity fed system.

[_Stormin_]

So you want an air rifle that fires bolts instead of pellets?

[AnthonyCumia]

So you want an air rifle that fires bolts instead of pellets?

Repeating air rifle that fires bolts, yes.

[elephant]

perhaps, re-designing the bolt would be the easy way to start. I'm thinking about a bolt with spring powered automatic expanding stabilizing fins that expand once the bolt is in flight. The bolt would be a simple tubular hollow shaft with a point on one end and some type of seal on the other. The bolt would be fired from a smooth bore barrel and once the bolt has left the barrel, the fins automatically engage and stabilize the flight? Not hard. Trajectory is another topic, but basically, your calculating the weight(mass) of the bolt, your expectation on total velocity(fpm) and total range(distance) and figure out how much air volume and air pressure you will need to achieve those results.

[Auto-X Fil]

How about removing the fletching from the arrow, and making it short enough to feed from a traditional magazine? Make it out of lead to keep the mass reasonable, and you've got a winner!

[AnthonyCumia]

perhaps, re-designing the bolt would be the easy way to start. I'm thinking about a bolt with spring powered automatic expanding stabilizing fins that expand once the bolt is in flight. The bolt would be a simple tubular hollow shaft with a point on one end and some type of seal on the other. The bolt would be fired from a smooth bore barrel and once the bolt has left the barrel, the fins automatically engage and stabilize the flight? Not hard. Trajectory is another topic, but basically, your calculating the weight(mass) of the bolt, your expectation on total velocity(fpm) and total range(distance) and figure out how much air volume and air pressure you will need to achieve those results.

Great minds think alike I did think about fins that retract as to make mag storage/feeding easier.

Any idea how that would happen? Any guesses?

What about cutting groves into the shaft of the arrow?

[SteyrAUG]

With your knowledge of ancient Chinese weapons, does this also plague the Chinese repeating crossbows of old? IIRC they had a gravity fed magazine on top like a Gatling, but instead of a crank they had a pump lever.

Seen lots of pictures of them, never actually seen a practical, working example.