GTA
All Springer/NP/PCP Air Gun Discussion General => Machine Shop Talk & AG Parts Machining => Engineering- Research & Development => Topic started by: condor22 on March 06, 2014, 07:31:53 PM
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Just something I have wondered about for years now. All mobile gun platforms utilize some method of gun stabilization. Battleships, tanks, railroad car mounted guns. Typically analog gyroscopes. A flywheel spinning at high rpm. Same principle that keeps spinning tops from falling over. Digital gyroscopes used in inertial navigation systems won't work, no spinning flywheel. Digital gyros are on a chip, a bit bigger than a postage stamp, if they can be used let me in on that theory.
A air rifle mounted stabilization system could consist two small analog gyro's, one on the Horizontal axis (windage) and one on the vertical axis (elevation). Mounted in a box about 3in. Use would be on demand, acquire the target. Press a button to engage the gyros. This should lock the rifle in place preventing any movement. Take the shot. Press the button again, to engage braking, to stop the spinning gyros quickly. It should be hard to move the air rifle with the stabilizer activated.
Shooting long distance, off hand or in windy conditions, could benefit from Air rifle stabilization.
Machining two small heavy, high speed flywheels, mounted solid, in a box with the drive motors shouldn't be hard to fabricate. The electronic motor drive and breaking circuits could be expensive, but doable. Or may be available as a package deal as motor/motor drive unit.
Seeking feed back, pros, cons, hair brained idea, Why it won't work or it just won't work on air rifles? :P
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I like it but know nothing about gyroscope dynamics :o
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One word,,,,,,,,,,,,,Torque Bringing a mass to speed in the time you're thinking about, will put the muzzle anywhere but target. :o Bringing it to a stop, would reverse the direction. ::)
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One word,,,,,,,,,,,,,Torque Bringing a mass to speed in the time you're thinking about, will put the muzzle anywhere but target. :o Bringing it to a stop, would reverse the direction. ::)
Hadn't thought about that, but easy to fix. Makes it a bit more complicated. Stacked, dual, counter rotating fly wheels. No more start-stop torque.
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Given that you have perfected your gyroscopic gun mount. Do you then have this mount attached rigidly to the stock? Is this intended just for PCP or planned for springers as well? Have you taken into account the z axis movement? How about the movement of the barrel as the pellet travels through it. That leaves one only to compensate for wind and pellet drop.
I think for it to work you would probably have to figure on the gyros spinning all the time. Regardless of whether they are counter rotating or not there is mass which must be put into motion. You can use a small motor over a long time or a larger motor over a shorter time. The mass is there regardless. Usually they are on pretty small bearings to reduce friction, too.
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just for fun
If you used a wheel 10cm across and 1cm thick made of steel and spinning at 1000 rpm you would have a gyroscopic couple force of 8kg
Thats significant.
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just for fun
If you used a wheel 10cm across and 1cm thick made of steel and spinning at 1000 rpm you would have a gyroscopic couple force of 8kg
Thats significant.
If you use 2 counter rotating wheels 10cm across and 1cm thick made of steel and spinning at 1000 rpm you would have a gyroscopic couple force of how much? ???
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2x8kg
It will just have much less precession
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The US Army has been testing Gyroscopically-stabilized rifles for more than a decade. The first Gyro units I saw looked like a small football mounted below the midpoint of the forearm. The latest ones look like a piece of PVC pipe.
They discovered a few odd things about them, IIRC. Depending on where the stabilizer was mounted, some heavy-barrelled rifles shot to a very different point of aim (Stabilized vs. Unstabilized) because the gyro resisted recoil to the point it affected a free-floated barrel (the action tweaking the barrel under recoil). The Gyros themselves couldn't take much recoil from large caliber rifles, either.
For a nearly recoilless arm, this might have some possibilities.
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My guess would be that if you ONLY shot it with the Gyro unit enabled, and sighted it that way, it would be OK, but I can certainly see the POI changing from unstablized....
Bob
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From what I getting from here, a rifle would need to be designed around the stabilizer, as an integral part of the rifle, rather than having stabilization unit added/attached to existing rifles. PCP Rifles only!
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Actually I don't think you need to get that complicated to test your theories. You could mount the gyros to hand stop rail on the forearm. As long as its strong enough to be rigid with the couple forces applied then it would be fine.
The fun part would be figuring out what plane to orient the gyro in to stabilize the gun
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One of my other hobbies is RC helicopters. Digital gyros would work, particularly an AVCS gyro also called "head holding" in the heli world. AVCS means Angular Vector Control System. But you would need servos to control the movement. The digital gyro just tells the servo to move in a certain direction, a certain distance, at a certain speed and all done VERY fast. A digital gyro would also be able to hold position better than a gyroscope gyro. The digital gyros can eliminate drift with AVCS type gyros, which I would think would be pretty important in your application. You can get very inexpensive AVCS digital gyros at HobbyKing.com as well as servos. The other problem is that you would need something to control the setup (you can also get at HobbyKing). It would basically become a joystick (remote) controlled gun. You could put a camera on the scope and use a controller to control the guns direction, the gyros would keep the gun pointed where you want and a button would become the trigger.
I have done this with an airsoft gun and an RC helicopter.
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I have seen rifle mounted gyros on occasion at the CASA FT matches. That is Hector Alfaro in the first picture. He is good shot and has cleaned the course before. He does not really need the gyro in order to shoot well, he just likes gadgets.
(http://i691.photobucket.com/albums/vv278/SDplinker/CASA%20FT/WP_000101.jpg)
(http://i932.photobucket.com/albums/ad168/HectorAlfaro/DSCN0132.jpg)
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Gyro-stabilzed Hamster....
Bob
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Special racing hamsters I would think. Probably sprinters.
Is this the general type of device on Hector Alfaro's gun?
https://www.ken-lab.com/ (https://www.ken-lab.com/)
Looks pretty slick.
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I hate to revise a dead post, but I love this idea. I've got a little bit of a motor reflex issue caused by repetitive session disorder type trauma and have issue holding still long enough to shot at long range. Couldn't you test your idea with some kind of hand loaded spring powered devise such as found on kids toys just as a quick and cheap proof of concept?
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Attach a angle grinder to the gun to test things? It will cause some stabilization effect with fast turning wheel.