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  1. #271
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    Dick,

    It was about 10.98" long and about 5.38" in diameter and weighed about 16.79 oz. without motor. It flew on a E15-4. I will see if I can attach the Rocksim file here. I looked at the file today. It needed to be moving about 40 fps leaving the rail and according to the simulation it was about half of that.

    Years ago I documented this build on Rocketry Planet.

    Attached Files Attached Files
    Last edited by aerostadt; 25th November 2016 at 02:30 AM.

  2. #272
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    Both appear to have been well underpowered. Need a CTI 1G G75. With that loaded it looks stable and you haven't considered base drag.

    Dick Stafford
    The Original Rocket Dungeon
    Volunteer compiler of product news for ROCKETS Magazine

  3. #273
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    In my haste I forgot one important thing....even if they did not fly so well, they look awesome!
    Dick Stafford
    The Original Rocket Dungeon
    Volunteer compiler of product news for ROCKETS Magazine

  4. #274
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    Quote Originally Posted by rstaff3 View Post
    I admire you for approaching these designs so scientifically. I neither have the launch site availability, or the patience, to try multiple iterations. If I don't get something going in 2 tries, it seems to get on the permanent back burner.
    Quote Originally Posted by aerostadt View Post
    I like KenEC's work on the finless design. It looks like the RAIStone has long slots in the side and flies well.

    I also tried an Apollo capsule design about 6 years ago for a Club Christmas oddroc contest. It had clear base fins, but did not do as well as KenC's model. It had AA batteries in the nose cone to light up Rudolph's nose. The large model went up only about 10 feet and did cartwheels. The smaller model did a little better. Rocksim said that it was stable, but it was not. I did not check the Rocksim simulation to see if there was a minimum velocity for leaving the rail.
    Thanks guys!

    Dick - For me, I wish I could give it a few tries and then shelve it, but all too often I'm OCD (my wife would say stubborn) and once I'm on it, I want to get it right. Unfortunately something like this is very difficult to get right. Still, sometimes I feel like a kid who just launched his first rocket when one of my wacky designs works...and that makes all those test flights worthwhile.

    Aerostadt - that capsule looks great! Also great holiday theme! I think you were on the right path with the big fins and they disappear against the snow too, which is awesome. However I think Dick is right that more thrust/speed off the rod is needed...the short & squat rockets are so draggy with the CP so forward that it's hard to overcome. Plus adding more motor doesn't necessarily solve things since the bigger motor brings the CG back, hence more nose weight & lower speed, therefore more motor...uh oh.
    Side effects of following my advice may include dizziness, frequent urination, decreased suction, vomiting, everything tasting like chicken and loss of rockets.
    METRA
    Radical Rocketeers
    NAR & Tripoli L2
    2016 Number of flights: 200+ (Losses=1 MIA)
    The most dangerous thing in this Forum isn't any rocket or motor...it is the "Reply" button. You have been warned.
    Believe it or not, I'm providing my opinion to try to help...annoying others is just a side benefit!
    ;)

  5. #275
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    Quote Originally Posted by rstaff3 View Post
    In my haste I forgot one important thing....even if they did not fly so well, they look awesome!
    I think so too!
    Side effects of following my advice may include dizziness, frequent urination, decreased suction, vomiting, everything tasting like chicken and loss of rockets.
    METRA
    Radical Rocketeers
    NAR & Tripoli L2
    2016 Number of flights: 200+ (Losses=1 MIA)
    The most dangerous thing in this Forum isn't any rocket or motor...it is the "Reply" button. You have been warned.
    Believe it or not, I'm providing my opinion to try to help...annoying others is just a side benefit!
    ;)

  6. #276
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    Click image for larger version. 

Name:	20161126_112448.jpg 
Views:	56 
Size:	162.1 KB 
ID:	306147

    It's coming along. Psuccess estimated at around 15%.
    Last edited by rstaff3; 26th November 2016 at 08:25 PM.
    Dick Stafford
    The Original Rocket Dungeon
    Volunteer compiler of product news for ROCKETS Magazine

  7. #277
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    I have been following this in the shadows and have been intrigued by the idea. The problem is that, as I was catching up on your progress, the wheels started turning and I started inventorying my spare tubes in my mind. I have some T20, T50 and T60 tubes downstairs that don't have pointy ends yet. It will be near spring before I can begin in earnest but I may have to try my hand at this

    My question is, have you done anything to alter the geometry of the air channel inside the rocket to utilize changes in internal air pressure/velocity to help stability?
    Bill

    I won't be wronged, I won't be insulted, and I won't be laid a hand on. I don't do these things to other people and I expect the same from them.
    John Wayne, The Shootist

    In the Hangar:
    A pile 'O' Fun

    On The Bench:
    Pieces 'O' Fun

  8. #278
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    Quote Originally Posted by Screaminhelo View Post

    My question is, have you done anything to alter the geometry of the air channel inside the rocket to utilize changes in internal air pressure/velocity to help stability?
    All I've thought about doing is smoothing the joint between the inner BT-60 and the lower plate. So far, I haven't addressed even that.
    Dick Stafford
    The Original Rocket Dungeon
    Volunteer compiler of product news for ROCKETS Magazine

  9. #279
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    Quote Originally Posted by rstaff3 View Post
    Click image for larger version. 

Name:	20161126_112448.jpg 
Views:	56 
Size:	162.1 KB 
ID:	306147

    It's coming along. Psuccess estimated at around 15%.
    Ooooh...that does look very good! Mindsim says 51% success!

    The mod I was mentioning was almost like that, however it wouldn't leave it fully open at the bottom and would instead have upside down "T" slots.
    Side effects of following my advice may include dizziness, frequent urination, decreased suction, vomiting, everything tasting like chicken and loss of rockets.
    METRA
    Radical Rocketeers
    NAR & Tripoli L2
    2016 Number of flights: 200+ (Losses=1 MIA)
    The most dangerous thing in this Forum isn't any rocket or motor...it is the "Reply" button. You have been warned.
    Believe it or not, I'm providing my opinion to try to help...annoying others is just a side benefit!
    ;)

  10. #280
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    Quote Originally Posted by Screaminhelo View Post
    My question is, have you done anything to alter the geometry of the air channel inside the rocket to utilize changes in internal air pressure/velocity to help stability?
    I actually did a LOT of things to alter the internal air pressure/velocity...however none of it was calculated or programmed..it was mostly trial, error, success and fine tune. For my RAIS rockets, I started testing with Area Rule/1:1; however each rocket seemed to need something different depending upon so, so many factors (speed, intake shape, length, weight, vent shape, etc.).
    Side effects of following my advice may include dizziness, frequent urination, decreased suction, vomiting, everything tasting like chicken and loss of rockets.
    METRA
    Radical Rocketeers
    NAR & Tripoli L2
    2016 Number of flights: 200+ (Losses=1 MIA)
    The most dangerous thing in this Forum isn't any rocket or motor...it is the "Reply" button. You have been warned.
    Believe it or not, I'm providing my opinion to try to help...annoying others is just a side benefit!
    ;)

  11. #281
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    Here's a bit more eye candy for those of you who are dedicated enough to read through 10 pages of this stuff...

    One of the test designs I was most proud of was this one which I thought up and made myself...helical vanes!









    It was really cool to build and spun the rocket up like mad. I only got a few tests on it and on it's first A10 launch, it went up straight, but there was an extended/faulty delay and it lawn darted before it ejected, causing major damage to the forward tube, to which the vanes were glued to the bottom of. It seemed to be a bad batch of A10s since two other motors from the same lot also exhibited very long delays. I did repair it (as well as I could) and also made another less "helical" version since it seems that the first spins the rocket almost too much. Both worked well (even did some tests without nose weight) and I am hoping to one day kit this design as the second & higher level "finless" kit after the RAIStone. Maybe one day.
    Side effects of following my advice may include dizziness, frequent urination, decreased suction, vomiting, everything tasting like chicken and loss of rockets.
    METRA
    Radical Rocketeers
    NAR & Tripoli L2
    2016 Number of flights: 200+ (Losses=1 MIA)
    The most dangerous thing in this Forum isn't any rocket or motor...it is the "Reply" button. You have been warned.
    Believe it or not, I'm providing my opinion to try to help...annoying others is just a side benefit!
    ;)

  12. #282
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    31st January 2013
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    Laying out those helical vanes makes my brain hurt. The idea I understand but getting them to fit would drive me up a wall.
    Bill

    I won't be wronged, I won't be insulted, and I won't be laid a hand on. I don't do these things to other people and I expect the same from them.
    John Wayne, The Shootist

    In the Hangar:
    A pile 'O' Fun

    On The Bench:
    Pieces 'O' Fun

  13. #283
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    Quote Originally Posted by KenECoyote View Post
    Here's a bit more eye candy for those of you who are dedicated enough to read through 10 pages of this stuff...

    One of the test designs I was most proud of was this one which I thought up and made myself...helical vanes!









    It was really cool to build and spun the rocket up like mad. I only got a few tests on it and on it's first A10 launch, it went up straight, but there was an extended/faulty delay and it lawn darted before it ejected, causing major damage to the forward tube, to which the vanes were glued to the bottom of. It seemed to be a bad batch of A10s since two other motors from the same lot also exhibited very long delays. I did repair it (as well as I could) and also made another less "helical" version since it seems that the first spins the rocket almost too much. Both worked well (even did some tests without nose weight) and I am hoping to one day kit this design as the second & higher level "finless" kit after the RAIStone. Maybe one day.
    That's awesome for sure. I don't know whether I'm more impressed with the concept or you ability to build it.
    Dick Stafford
    The Original Rocket Dungeon
    Volunteer compiler of product news for ROCKETS Magazine

  14. #284
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    Quote Originally Posted by rstaff3 View Post
    That's awesome for sure. I don't know whether I'm more impressed with the concept or you ability to build it.
    Thanks Dick! I'm flattered! Once you get the arc correct, it's not that hard. I actually tried some calculations, but they didn't work right and in the end it was simpler to try trial and error...guess the arc...too big, try less...too small, try more, etc. I work on the computer all day and likely for most of my time now, but I usually prefer to just work with my hands when building things.

    Building this gave me the idea of the spiral rotating fins on the summer build-off. If I do start making kits, I would likely have the modular can rockets as the first kit since they aren't difficult to build, they fly so well and are just plain fun.

    If I get this helical finless version done up as a test kit I'll send the first one to you to try - it shouldn't be hard...biggest problem is finding the time & templates and making the instructions. Just don't wait on me or hold me to any specific timing since work gets obscenely crazy for me this time of year all the way through January - once it was really busy through March...ugh.
    Side effects of following my advice may include dizziness, frequent urination, decreased suction, vomiting, everything tasting like chicken and loss of rockets.
    METRA
    Radical Rocketeers
    NAR & Tripoli L2
    2016 Number of flights: 200+ (Losses=1 MIA)
    The most dangerous thing in this Forum isn't any rocket or motor...it is the "Reply" button. You have been warned.
    Believe it or not, I'm providing my opinion to try to help...annoying others is just a side benefit!
    ;)

  15. #285
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    Quote Originally Posted by KenECoyote View Post
    If I get this helical finless version done up as a test kit I'll send the first one to you to try - it shouldn't be hard...biggest problem is finding the time & templates and making the instructions. Just don't wait on me or hold me to any specific timing since work gets obscenely crazy for me this time of year all the way through January - once it was really busy through March...ugh.
    Or, you could kit up a finless SSC. I know, lots more challenges to iron out on that but it would certainly be a departure from the 3FNC pattern.
    Bill

    I won't be wronged, I won't be insulted, and I won't be laid a hand on. I don't do these things to other people and I expect the same from them.
    John Wayne, The Shootist

    In the Hangar:
    A pile 'O' Fun

    On The Bench:
    Pieces 'O' Fun

  16. #286
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    Quote Originally Posted by Screaminhelo View Post
    Or, you could kit up a finless SSC. I know, lots more challenges to iron out on that but it would certainly be a departure from the 3FNC pattern.
    Actually I was just thinking of something like that this afternoon...my current 29mm mmt SSC is modular and can accommodate the ball bearing 38mm fin can (which I really, really want to finish) and therefore, I believe I can try a spinning vented finless can (54mm?) as a test after that...hmmm....
    Side effects of following my advice may include dizziness, frequent urination, decreased suction, vomiting, everything tasting like chicken and loss of rockets.
    METRA
    Radical Rocketeers
    NAR & Tripoli L2
    2016 Number of flights: 200+ (Losses=1 MIA)
    The most dangerous thing in this Forum isn't any rocket or motor...it is the "Reply" button. You have been warned.
    Believe it or not, I'm providing my opinion to try to help...annoying others is just a side benefit!
    ;)

  17. #287
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    I hate when I think I'm on to something just to find its been done . I've enjoyed reading this thread and understand where you're going while curious about something too. On your earlier rockets, what if you left the base open, forego the slots, and extend the outer tube and internal vanes two or three inches below the lip of the motor (taper the fins to the external wall)? You have the helical fin directing air along the airframe already. The heated air from the motor mixing with the air along the lower part of the helical will increase the flow through the outer can thereby increasing the pressure somewhat, of the air being pulled in. Plus it should keep the heat from the motor from coming in to contact with the outer casing (boundary layer air). In my novice mind, the endplate is also a drag inducer internally, adds weight, and also creates a cavitation wave behind the rocket. Cool concepts, great learning experience for me, and enjoyed the vids. Hope your neighbors are understanding
    Instructions are just another man's opinion...

  18. #288
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    and then I find part of the answer! There is sooo much info available on this forum. Thanks to all that offer their insight!
    http://www.rocketryforum.com/showthr...entation/page3
    Instructions are just another man's opinion...

  19. #289
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    Quote Originally Posted by Knuckledragger View Post
    On your earlier rockets, what if you left the base open, forego the slots, and extend the outer tube and internal vanes two or three inches below the lip of the motor (taper the fins to the external wall)?
    You sir, sound like you would enjoy something called Gas Dynamic Stabilization!

    Guaranteed to get you some sideeye at every launch!

  20. #290
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    Thanks Nytrunner, I am, finless and GDS combined. Boyles' laws, boat tails, laminar airflow, drag vortices, CG/CP, divergent surfaces, and airfoilless designs dance through the vast void of my noggin daily. I keep a notebook of ideas that I sketch out when the thought or possibilities hit me. Last night, I came across the info on here and saw that others are chasing that rabbit too. I read your link and bookmarked it for reading later tonight. Thank you. What happens if the lower tube is a couple of millimeters larger than the upper and the upper is boat tailed? Over thinking this or unnecessary weight? As for an internal fire retardant in the lower tube, has anyone used crushed perlite adhered to the inner tube as an insulator from the nozzle exhaust heat? A slurry would introduce the adhesive to the heat and conduct it. I was wondering if the tube was coated with a thin coat of glue and perlite dust was poured and shaken inside that tube, the insulative property somewhat protect the adhesive. Will have to raid the wife's gardening supplies and introduce it to a blowtorch! Just a hair brain thought.
    Instructions are just another man's opinion...

  21. #291
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    I've been applying Minwax wood hardener to the back end of my GBIs. Its helped the delamination although my first few launches were without it. The first two barely had scorch specks, but it started bubbling slightly on the 3rd. That's with BP motors, I haven't tried Composites yet (although I've got an extra D10 in my box!)

    Forward tailcone and enlarged rear tube inlet? The tailcone sounds cool, I'm worried the larger tube would become a giant rearwards ring fin with the associated drag.

    There are only a couple ways to find out though: Build or Compute! (either way, please return the results to us )

  22. #292
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    Quote Originally Posted by Nytrunner View Post
    I've been applying Minwax wood hardener to the back end of my GBIs. Its helped the delamination although my first few launches were without it. The first two barely had scorch specks, but it started bubbling slightly on the 3rd. That's with BP motors, I haven't tried Composites yet (although I've got an extra D10 in my box!)

    Forward tailcone and enlarged rear tube inlet? The tailcone sounds cool, I'm worried the larger tube would become a giant rearwards ring fin with the associated drag.

    There are only a couple ways to find out though: Build or Compute! (either way, please return the results to us )
    The best way to do this would be to get a baseline design then make copies with variations. Various inlet sizes, varying GDS tube diameters or whatever. I am too impatient for that, unfortunately.

    Basically unrelated, but the water rocket folks commonly use a ring fin that is the same diameter as the body but is offset below the nozzle with spars. Always wanted to try that on a small Estes class rocket.
    Dick Stafford
    The Original Rocket Dungeon
    Volunteer compiler of product news for ROCKETS Magazine

  23. #293
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    I find that as I think I have a great idea, like pyramids in Egypt and Latin America, someone did it already! But then again, the V-22 Osprey and B-2 aren't new designs...
    Images aren't attaching for some reason, computer or web, but here is the link http://warisboring.com/from-nazi-ger...ruise-missile/
    Minus the wing, with a convergent inner tube and the motor being farther aft for CG purposes, is it a ring fin or passive expansion nozzle? Will have to do my homework on Ring Fin concepts.

    If you're replying, you're teaching, and I thank you.
    Instructions are just another man's opinion...

  24. #294
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    The page would not fully load on my phone ...will look at the site later. There are multiple things that tend to creep in together. Ring fins provide stabilty, air intakes help to defeat Mr. Krushnik, thrust augmenters do nothing with our short burn motors and at low speed, GDS tubes add stability but have a limited range of designs on which they work, RAIS (ram air induction stabilization) works but is also limited in what it can do.
    Dick Stafford
    The Original Rocket Dungeon
    Volunteer compiler of product news for ROCKETS Magazine

  25. #295
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    Quote Originally Posted by rstaff3 View Post
    The best way to do this would be to get a baseline design then make copies with variations. Various inlet sizes, varying GDS tube diameters or whatever. I am too impatient for that, unfortunately.

    And then there's me, who chooses a target geometry and stubbornly insists on trying to make it work.

  26. #296
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    Quote Originally Posted by Nytrunner View Post
    And then there's me, who chooses a target geometry and stubbornly insists on trying to make it work.
    That's more me too
    Dick Stafford
    The Original Rocket Dungeon
    Volunteer compiler of product news for ROCKETS Magazine

  27. #297
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    Quote Originally Posted by Nytrunner View Post
    And then there's me, who chooses a target geometry and stubbornly insists on trying to make it work.
    Quote Originally Posted by rstaff3 View Post
    That's more me too
    Umm...mee three?

    Sorry I've been away guys...life happens. Looking forward to getting back to this, but for now it seems to be at the limits of stability and fairly inefficient, so it would take a LOT more testing (which I'm not at the luxury of doing at this time). The recent discussion does make things interesting though. I'd love to really test the limits by combining some of the things mentioned recently, but that just muddies things up as to what is really working to help with stability.

    Still, this has been an extremely interesting and cool endeavor for me so far and I hope to continue it when I have more time. Thanks for everyone's attention, feedback, input and patience.
    Side effects of following my advice may include dizziness, frequent urination, decreased suction, vomiting, everything tasting like chicken and loss of rockets.
    METRA
    Radical Rocketeers
    NAR & Tripoli L2
    2016 Number of flights: 200+ (Losses=1 MIA)
    The most dangerous thing in this Forum isn't any rocket or motor...it is the "Reply" button. You have been warned.
    Believe it or not, I'm providing my opinion to try to help...annoying others is just a side benefit!
    ;)

  28. #298
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    Quote Originally Posted by KenECoyote View Post
    Sorry I've been away guys...life happens.
    Nice to have you back. Hope all is well.
    Recently completed: upscale Quinstar; in progress: APRO Lander II and Starship Avalon
    My photo albums: fleet pics and OR Models

  29. #299
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    Quote Originally Posted by neil_w View Post
    Nice to have you back. Hope all is well.
    Thanks Neil! Life can at times get a bit "unstable", but I'll always aim to get up off the ground.

    Side effects of following my advice may include dizziness, frequent urination, decreased suction, vomiting, everything tasting like chicken and loss of rockets.
    METRA
    Radical Rocketeers
    NAR & Tripoli L2
    2016 Number of flights: 200+ (Losses=1 MIA)
    The most dangerous thing in this Forum isn't any rocket or motor...it is the "Reply" button. You have been warned.
    Believe it or not, I'm providing my opinion to try to help...annoying others is just a side benefit!
    ;)

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