FlaMtnBkr Posted June 18, 2016 Share Posted June 18, 2016 If that was for my benefit, I got that down. Thank you. It's the "gyroscopic precession" I can't fully picture. Link to comment Share on other sites More sharing options...
lloyd Posted June 18, 2016 Share Posted June 18, 2016 I posted this elsewhere. It's an explanation I got from an older engineer back (way back) when I was 22, and it explained precession in a way that finally made sense:0---------0Precession can be hard to explain in terms of a spinning wheel. It's hard to imagine how putting a force on a wheel can have its effect 90-degrees further along the rotation. But it's EASY to understand if you look at it in terms of orbital mechanics. Just imagine a SINGLE particle in orbit around a point. Now, apply a force at any point along its flight that is perpendicular to the orbit and parallel to the old axis of rotation. You'll immediately see the particle's vector change; it doesn't move away from the applied force at the point where that force was applied, but changes it's path away from that point. The plane of rotation changes in a way that makes it seem to 'pivot' about the point where the force was applied. If that isn't too clear initially, imagine a billiard ball rolling slowly down the table from end to end. A ball is shot across the table such that it hits the first one right as it passes the side pockets. Now... ask yourself... does the first ball continue in a straight line perfectly parallel to its original track, or does it now 'angle away' from the original track? And... of course, the answer is it 'angles away'. The same thing happens in orbital mechanics, but "in the round". A gyroscope is just a large mass of particles orbiting together. LLoyd Link to comment Share on other sites More sharing options...
JohnFRoss Posted June 19, 2016 Share Posted June 19, 2016 (edited) I have seen similar items with a small report at the end, how is that accomplished? I did it by using a tube length that was longer than standard for the spindle I was using. Drill the tangential hole 1/2 tube ID above the tip of the spindle. Press your rocket with your chosen fuel up to the tip of the spindle. Then switch to a slower "delay comp" above the spindle for 1 1/2 tube I.D., so there is twice as much delay comp above the fuse as compared to between the fuse and spindle tip. Now press a clay bulkhead with a hole in it, either with a tool from Caleb or drill a hole by hand. Now put in your choice of loose report comp in the remaining space and glue an end disc on the top of the tube. Make sure you light this device in an area where there are no things you would mind damaging within range, particularly in the larger sizes... Edited June 19, 2016 by JohnFRoss Link to comment Share on other sites More sharing options...
dagabu Posted June 21, 2016 Share Posted June 21, 2016 I did it by using a tube length that was longer than standard for the spindle I was using. Drill the tangential hole 1/2 tube ID above the tip of the spindle. Press your rocket with your chosen fuel up to the tip of the spindle. Then switch to a slower "delay comp" above the spindle for 1 1/2 tube I.D., so there is twice as much delay comp above the fuse as compared to between the fuse and spindle tip. Now press a clay bulkhead with a hole in it, either with a tool from Caleb or drill a hole by hand. Now put in your choice of loose report comp in the remaining space and glue an end disc on the top of the tube. Make sure you light this device in an area where there are no things you would mind damaging within range, particularly in the larger sizes... Outstanding! Thanks john, that is much as I envisioned it to work like but I am thrilled that you have made them work! So much testing I don't have to do now. Link to comment Share on other sites More sharing options...
dagabu Posted July 30, 2016 Share Posted July 30, 2016 I made some very large Zipps this week with a few different hole locations and nozzle sizes. These will get fired at PGI this next weekend and I will take all the video I can. Here are some pictures of the finished ones. Link to comment Share on other sites More sharing options...
pyrojig Posted July 30, 2016 Share Posted July 30, 2016 (edited) I have seen these devices with a small load of slow flash and stars . The effect is like a cheap insert from a cake, but a working burst at the apex of flight. I was most impressed that they got these 1" x3" devices to fly vertical with a heavy payload off setting the balance of the device. It was constructed as john describes but with 1/8" stars in the loose flash/burst. I have put together a jig for these in the 1/2 and 3/8 sizes, but they dont have a report.//// not at least yet. They are a very rewarding effect for min. materials and tooling . + kids go absolutely nuts when they see them being shot. Love the neighborhood dogs howling after the zip of these devices. ( dont have updated pics of the new tooling but some of the 1st ones I started with ) http://i918.photobucket.com/albums/ad24/pyrojig/content---media-external-images-media-44.jpg http://i918.photobucket.com/albums/ad24/pyrojig/content---media-external-images-media-38.jpg Edited July 30, 2016 by pyrojig Link to comment Share on other sites More sharing options...
lloyd Posted July 30, 2016 Share Posted July 30, 2016 The 'secret' to the report is to press the charge with a 'header' portion of powder above the core, and below the top of the tube by whatever distance you deem necessary to put in some flash and a top seal (probably of hot glue, or an invert cap, white glue, and THEN a dose of hot-melt, if you're delicate about letting hot-melt touch flash). Lloyd Link to comment Share on other sites More sharing options...
pyrojig Posted July 31, 2016 Share Posted July 31, 2016 I want to re-create the cool effect of a star burst . It seems necessary to get a tight packing so the stars/load doesn't shift. I love the fact that hot glue is way under temp to be of danger for flash . It seems like it was meant for pyro use. lol Link to comment Share on other sites More sharing options...
schroedinger Posted July 31, 2016 Share Posted July 31, 2016 The 'secret' to the report is to press the charge with a 'header' portion of powder above the core, and below the top of the tube by whatever distance you deem necessary to put in some flash and a top seal (probably of hot glue, or an invert cap, white glue, and THEN a dose of hot-melt, if you're delicate about letting hot-melt touch flash). LloydJust fill the last void and cover with Al tape. Link to comment Share on other sites More sharing options...
mondalfiona Posted December 4, 2017 Share Posted December 4, 2017 (edited) If anyone is interested in making these I have a Tutorial I could dig out. https://www.youtube.com/watch?v=utqnO1DBFyk https://www.youtube.com/watch?v=7mikXso4T_g https://www.youtube.com/watch?v=N38GI7Bm3f0I wish to learn this process of making. Edited December 4, 2017 by mondalfiona Link to comment Share on other sites More sharing options...
dagabu Posted December 7, 2017 Share Posted December 7, 2017 Only 16 months late but here is the video of my zips. 2 Link to comment Share on other sites More sharing options...
Mixer Posted December 7, 2017 Author Share Posted December 7, 2017 (edited) They only work and sound as intended if they are kept small. A good effort though For those interested, the article is in `Member Tutorials` Edited December 7, 2017 by Mixer Link to comment Share on other sites More sharing options...
calebkessinger Posted December 7, 2017 Share Posted December 7, 2017 That was a nice one.. Whistle would liven it right up! The big ones can put the hurt on ya if you get hit with one. Link to comment Share on other sites More sharing options...
Svimmer Posted December 8, 2017 Share Posted December 8, 2017 These looks fun defintley something i need to try. Do i need the tool to drill the side ? or does it just make the job 10 times easier. Link to comment Share on other sites More sharing options...
Mixer Posted December 8, 2017 Author Share Posted December 8, 2017 These looks fun defintley something i need to try. Do i need the tool to drill the side ? or does it just make the job 10 times easier.A tool is very useful if you are making a lot of them. I made mine from a piece of aluminum angle. 1 Link to comment Share on other sites More sharing options...
Recommended Posts