Notice on this wadcutter the build up of air in front of the flat nose make it's own wave
because it's acting as a solid.
http://bulletin.accurateshooter.com/...ripple-bullet/
notice even the small meplat shows a build up of air between shock wave and bullet.
The holey Bullets seem to have disappeared
this was the "Comp Bullet" - an Italian company design
many claims for it magical holiness.
Last edited by Artful; 09-28-2013 at 03:02 PM.
je suis charlie
It is better to live one day as a LION than a dozen days as a Sheep.
Thomas Jefferson Quotations:
"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government."
You know what would be really funny? If in the end, I was able to get my uneducated theory to actually work. That would be hilarious to me. I think that, that reason alone is enough to make an attempt worth while; even if it's just another failed attempt at something that's already been tried.
I can see why many would state or agree that such a cockamamy idea wouldn't work. And, when viewed or attempted from the perspective of their education, experience or whatever, they're most likely right. It's destined to fail before it's even started.
I don't view it from inside the same box that their viewing it from. In spite of this I'm under do illusion that the "Box" I'm working outside of is any more or less conducive to reaching a successful end of such a project. I think it's just a matter of one person viewing things from a different perspective that another.
HollowPoint
Ok, so what's the easiest way to trial your theory? - first calculate the twist needed on your fin's, then find a lathe or screw machine that's free to play - make it out of copper, brass or bronze I'd say as lead isn't very machinable. What can we do to help?
Looking at your original post do you have a gain twist on the wings/fins - what do you want to call them?
Last edited by Artful; 09-28-2013 at 05:27 PM.
je suis charlie
It is better to live one day as a LION than a dozen days as a Sheep.
Thomas Jefferson Quotations:
"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government."
You need to hook up with the guy in a forum up top that has made tons of custom molds of all sorts of designs. IIRC he had little houses on top, some looked like driver tips and I think he was even working on a screw mold at one point.
This is his thread.
http://castboolits.gunloads.com/show...ps-head-anyone
Excellent - I remember that thread now -
http://castboolits.gunloads.com/show...91#post2407591
je suis charlie
It is better to live one day as a LION than a dozen days as a Sheep.
Thomas Jefferson Quotations:
"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government."
Gee guys that is what I suggested in the beginnig. "Phillips head anyone" by OLDPARA He is pretty sharp onthe programs and design of some fantastic art style bullets that do shoot pretty well.
Hollowpoint I say go for it and I hope you suceed and prove some doughter wrong. Even if you don't suceed completly you will have further imfor. to try again with an adjusted design. As one of my old boss's said" I may not always be ALL right ,But I will never be ALL wrong!!!
Good luck
CD
Sure enough, right there in post #8. I didn't remember the Op's name or the name of the thread, until I found it again.
He even made one on a suggestion that had threads on it. I beleive it was about a 5/16s tap in size. Be interesting to see the air wave off of it! I would think if it shoots a reasonable group and has a lower noise level then Hollowpoints design could be considered a success, yes or no???? We all would learn something from it anyway.
CD
The threaded mold part is page 5 starting around post 87 or so.
The image and the analogy I posted are just that; just and image to give you an idea of what my theory is based on. The tunnel-digging analogy was just to paint a mental picture but, some have taken these examples far to literally so it's no wonder there's so much doubt surrounding my theory.Originally Posted by Artful
I do envision the initial prototypes being machined from brass or copper rod but, for the bench testing this won't be necessary. I planned on turning a one inch piece of delrin rod to the desired bullet profile, attaching adjustable Impeller-Fins so that I don't have to turn a new example with every degree of adjustment I make to the fins.
I have air tools that spin at real high RPMs. I can adapt one of them to spin my mock-up in order to adjust the fins on the Impeller section of my bullet to the optimum air-flow position. This can be done by mounting this test-bullet inside an enclosure with a small viewing window. Smoke or water can be used as the medium to simulate the movement of air flowing around and past the bullet.
Once the proper pitch is established for the Impeller-Fins, I can then move forward to calculating with mathematics what I can expect when or if the bullet is moving forward at a given velocity and at a given rate of spin.
The tail end of my delrin mock-up-bullet will have the heel threaded so as to be able to screw on different boat-tail lengths or angles. Again; this is so that I don't have to turn a new delrin mock-up bullet in order to hit on the right length or angle for the boat tail heel. It should be just a matter of making up boat tail heels that I can quickly swap out until I get the optimum configuration. Even better still might be the use of an old antenna-type of set-up that consists of various diameter hollow rods; one fitting snuggly inside the other mounted on the heel of my mock-up and just sliding them in or out to the optimum length.
Right now I'm just telling you the steps that I hope to go through as I envision it in my mind; not what I've actually done so far. I don't see it as being as complicated as many seem to believe. Maybe it's because I'm just to much of a simpleton.
In my mind, the price of success and the price of failure are exactly the same. We all know that failure is easy to achieve. From this point of view, achieving success should be easy; provided you go about it correctly.
Even with what I've written up to now, I've gotten way, way, way ahead of myself. I still have to finish the final stages of my Boat-Tailed Gas-Checks project and then finish up the upgrade of my Soft-Pointing-Tool. Then I can think about move forward to trying to prove this Sonic-Crack-Theory.
I came up with this theory just lately while was laying on my back feeling under the weather. Now that I'm back on my feet I can make plans to finish up one project and move onto the next.
I'm afraid I've gotten back into the bad habit of posting my ideas before I've had a chance to prove them. I had stopped doing that shortly after joining this forum but, with the success I've had with the Boat-Tailed Gas-Checks idea I'm afraid I let myself drift back into this bad habit.
After this thread runs its course I won't be posting any more of my ideas, theories or inventions until I've had a chance to complete them. In any forum-setting there are just way to many dream-killers with good intentions to keep one from bringing their dreams to fruition. I thank God for those here who still have dreams of their own and encourage others who do.
In regard to the work that our fellow forum member oldpara goes; I've been following his post since he started the thread in question. He has some awesome creations. I love that kind of stuff. I absolutely love it. I've always been drawn toward creative people but, in my own case and with my own ideas, I prefer to do all my own work. This way any failures I encounter are my own and any successes I achieve are my own; otherwise it's to easy to blame others for one's failures and to easy for others to steal your successes.
Artful: I don't think I've ever mentioned to you how grateful I am for your inputs on this and some of my threads throughout this forum. I may be way off base with my interpretations of the number of hits that some of my other project-threads have gotten over time but, I'm thinking there are thousands of lurkers on these threads that never say a word one way or the other. Then there are those who chime in with their well meaning cliches only to tell me why they think my ideas won't work. And then there's yourself and a handful of others that will post replies of encouragement. Many thanks for the offers to help.
Right now I have my hands full with the projects I'm working on now. If any of you want to help, here's how you can help me. Next time you say your prayers, mention me and this project. I'm kind of wanting to see it succeed.
HollowPoint
Last edited by HollowPoint; 09-29-2013 at 01:52 PM.
Ok, we'll leave it in your hands - glad your feeling better - one suggestion look into super sonic propeller driven plane history.
je suis charlie
It is better to live one day as a LION than a dozen days as a Sheep.
Thomas Jefferson Quotations:
"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government."
As you already have the solid drawing, any chance that you could just get someone to 3D print your prototypes?
The small amount of information on "Propellers" (not Impellers) that I came across seemed to indicate that a "Propeller-Type" of configuration would become limited by the Propeller itself.
In the old WWII aircraft for example, the air speed of these craft would only allow then to travel up to a certain speed before the propeller started hindering the flight characteristics of the plane. I can't remember exactly what that air speed was but, this is the reason I opted for the "Impeller" configuration as apposed to the "Propeller" configuration. Both will suck volumes of air and create forward momentum but in my estimation, the "Impeller" configuration does so with less resistance.
Even so, I'll check into your suggestion a little more.
It is possible to have prototypes 3D printed. Both in the plastic medium that the lower end printers put out and in "Sintered" metal 3D printing. The "Sintered" metal printing would be out of the realm for me because It's to expensive; especially if more than one prototype is needed.
The plastic medium 3D printing wouldn't be so bad but, I have the lathe and mill to make up these prototype so why pay the additional expense of 3D printing them?
I'm doing it on the cheap. It's a basically a million-dollar idea with a fifty-dollar R and D budget. (optimistic I guess)
HollowPoint
Non engineers have solved lots of the worlds mysteries and needs...I for example devised a disposable handkerchief many years ago...didn't pursue it and someone did...it's called Kleenex.
Whatever comes of the whole thing...I like the CAD design drawing
opos:
Thanks for the kind word.
I'm tickled that the drawing came out as clear as it did. I used the Solidworks software to draw it up. I'm self-taught so my drawings don't always come out as I'd like.
I've mentioned this before in some of my other post and topics. When you're self-taught, you have a teacher that's just as ignorant as the student. It's a hit or miss affair.
HollowPoint
The thing about being self taught is there is no lesson plan, which slows the learning process - but it also allows side trips to things outside a traditional course of education. At one point I thought I had a unique idea for a suppressor baffle design - turns out it was a reinvention - I have one now made by someone else and it works well for what it is, not the quietest but the quietest for it's size.
Let me spark your fertile mind
http://www.heliciel.com/en/logiciel-...s%20helice.htm
http://en.wikipedia.org/wiki/Republic_XF-84H -
"Thunderscreech" was an experimental turboprop aircraft derived from the F-84F Thunderstreak.
Powered by a turbine engine that was mated to a supersonic propeller,
http://www.langleyflyingschool.com/P...0Part%201.html
http://history.nasa.gov/SP-4219/Chapter14.html
An advanced propeller swirl recovery model is shown in the NASA Lewis Research Centers 8 x 6 foot supersonic wind tunnel. Propeller efficiencies and noise are measured at cruise much numbers up to 0. 80 and at takeoff and approach conditions. Vane pitch angles and propfan-to-vane axial spacings are varied. The testing was part of the Advanced Turboprop Project, with the goal of providing the technology base to enable the U.S. development of quieter, fuel efficient turboprop engines with a comfortable aircraft interior environment. (NASA photo no. 90-H-78).
You of course don't need the entire propeller as your not using it as a driving force.
Remember Air is compressible - Liquids are not so much
The other thought is Ventura effect and ducting like the bullet I showed above. I never bought any but the hole taking air into a central chamber and allowed to exit out the back is a interesting idea - no? What if you combined the two - your prop/impeller directing towards a vent into the body to exhaust out the back?
Last edited by Artful; 09-30-2013 at 06:13 PM.
je suis charlie
It is better to live one day as a LION than a dozen days as a Sheep.
Thomas Jefferson Quotations:
"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government."
When we picture our own ideas in our minds we're able to see them in their perfect state. When I picture my own theory as it pertains to the bullet design I have in mind, I can see it as I want it to be, functioning as I want it to function; and it functions perfectly.
Fabricating and testing our ideas generally turns out to be anything but perfect.
It can be incredibly difficult to explain our personal views of our perfectly envisioned idea to others, especially when trying to do so with the written word.
I'm having trouble wrapping my head around the "Propeller" as a viable method for this particular application. My difficulty in understanding how a Propeller would work is due to the interior dimensions of a rifle bore.
My miniscule understanding of Propellers as a means of creating forward momentum of any kind is that the Propeller blades themselves have to have a certain amount of length in order to have the surface area to displace sufficient amounts of air to accomplish their intended task.
On an aircraft, the Propellers can be made as long and as many as needed for optimum performance because they're basically rotating in open air. On a 30 caliber bullet launched at 2700 fps, I'm picturing a Propeller being sheared off by the velocity and centrifugal force as soon as it leaves the muzzle.
To my way of thinking, Propellers are used to pull an object forward. I'm not sure exactly how to describe it so it makes sense to everyone but, the Impeller setup I'm envisioning is design to bore a bullet-sized-diameter hole through the air in front of my bullet, pulling that bit of air backward and thus mitigate or eliminate the pressure wave that would otherwise stack up in front of the bullet and eventually initiate a Sonic-Crack.
I don't know if this makes any sense or not. It's just the way I picture it in my mind.
Perhaps a Propeller setup will work as you're seeing it in your mind. I'm struggling to see it that way. Maybe you can elaborate a little more. Then it might make it easier to see it how you're see it.
HollowPoint
Last edited by HollowPoint; 10-01-2013 at 05:24 PM.
I wish I had the computer drawing skills to picture what I see in my minds viewpoint ... but alas I do not. If you look at your original drawing I'm seeing your impeller and I'm seeing the air build up in front of it. As the boolit rotates at high RPM it's trying to cut into the compressed air and move it out of the way.
I see a change in the impeller to make the bite work better in supersonic air - if you keep the vanes and use them to channel the compressed air to a vent on the body of the boolit that connects to a central cavity that has an exit to the rear you can move the compressed air out the back into the low pressure zone that forms behind a normal boolit. In the past the air force did this and several car makers do so also to improve the aerodynamic's.
In the airplane pictures, you have to understand the propellers stick out so they have a place to move the air (behind the aircraft), what I'm trying to get you to see is the supersonic propellers don't look like grandpa's propeller for sub-sonic aircraft - they have a different shape to try and keep turbulence from forming and making more drag. I don't see a boolit with prop sticking out
Even if you just took a regular J-word bullet - drilled a central cavity from the back and then cut smaller holes in such a way as to help scoop the air into the cavity and exhausted out the rear (much as the Italian design) it might make a difference - I don't know.
I'd ditch the holes around the mid-section and move the remaining ones further up the ogive and angle them to help pull air in.
Last edited by Artful; 10-01-2013 at 09:46 PM.
je suis charlie
It is better to live one day as a LION than a dozen days as a Sheep.
Thomas Jefferson Quotations:
"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government."
Sorry, it's not the burble that causes the boom. It's the >1000x pressure cone that your ear detects. Note the primary wave and secondary waves in the pic. If you can cause the waves to make an interference pattern, you can reduce the boom. If you make the interference pattern 'move' you can mask the identifiable noise.
Whatever!
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