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  1. #31
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    Most production motors are reliable if handled properly.

    Over the years I have had two motors CATO during two different highly clustered flights. Both times none of the other motors were affected and the flights completed successfully.

    Never had a problem with an Estes or CTI motor.

    Boris Katan
    NAR / TRA L3
    Lots of fun cluster rocket pictures and video at: www.bpasa.com

  2. #32
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    I had what appears to be a faulty batch of Estes E9s earlier this year. 4 out of 6 blew their nozzles on ignition, and a number of our local club members had problems with them as well--apparently we all buy from the same big box retailer. These do happen.

    However, I feel that the key difficulty of the 300-D flight Mark is describing is insufficient thrust safety margin. If one or two motors explode but the rest provide enough thrust for safe flight, I feel quite comfortable with that flight.

    Ari.

    2013 41,122Ns; 2014 27,030Ns; 2015 23,202Ns; 2016 16,474Ns

  3. #33
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    Ari / iter,

    Your Vulcan rocket glider (link in signature) is gorgeous. A real work of art.

    Could I buy the same shaped wings from FlyingFoam?

    Agree that a thrust safety margin is key for clusters.
    Boris Katan
    NAR / TRA L3
    Lots of fun cluster rocket pictures and video at: www.bpasa.com

  4. #34
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    After gradually sanding down stage mating surfaces for over an hour, got the "just right" fit for the booster into the sustainer. The same snug but not stuck fit used for a NC, just enough to stay in place until tugged.

    Then attached the ring fins. These are 6" phenolic liner parts I had laying around that seem to be the perfect balance of weight, thickness, strength and size. The size of the pieces I had on hand required second stage fins to be out of alignment with first stage.

    Still plenty of clearance for the launch rail and lots of stabilization surface.
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    Boris Katan
    NAR / TRA L3
    Lots of fun cluster rocket pictures and video at: www.bpasa.com

  5. #35
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    Attached is screenshot of proposed Raven3 settings.

    Flight profile and staging criteria are listed in first post of this thread.

    Does channel 3 look correct for stage 2 firing channel?

    Channels 1 and 2 will handle dual deploy. Channel 4 is not used.
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    Last edited by delta22; 30th October 2012 at 02:43 AM.
    Boris Katan
    NAR / TRA L3
    Lots of fun cluster rocket pictures and video at: www.bpasa.com

  6. #36
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    Quote Originally Posted by delta22 View Post
    Ari / iter,

    Your Vulcan rocket glider (link in signature) is gorgeous. A real work of art.

    Could I buy the same shaped wings from FlyingFoam?

    Agree that a thrust safety margin is key for clusters.
    Thank you for your compliments Boris. Yes, you can call Coby and say, "I want what Ari's having." You may want to double-check the OD of your fuselage tube. I got it slightly undersize--enough to fit a thin-wall BMS BT70 tube but too small for LOC 2.14. If you decide to use LOC tube, tell Coby to cut the larger diameter. This allows you to use standard CRs instead of laser-cutting custom ornaments as I do. Also, now that it's flying, I wonder about omitting the 38mm MMT and just using a 54mm retainer. AeroTech J90 is calling me.

    Ari.
    2013 41,122Ns; 2014 27,030Ns; 2015 23,202Ns; 2016 16,474Ns

  7. #37
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    I like the flame job on your Fatboy! It's remarkably similar to my Vulcan's--I wonder if I'm subconsciously following your pattern here. If yours homemade, from Stickershock or where?

    Ari.
    2013 41,122Ns; 2014 27,030Ns; 2015 23,202Ns; 2016 16,474Ns

  8. #38
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    I remember a few batches of D12s that were bad at least 10 years ago. My viper IV had to have all 4 motor mounts replaced at one point or another. Don't think it was ever 2 at a time.
    Kevin Wuchevich
    Tripoli Pittsburgh
    TRA 12238

  9. #39
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    Quote Originally Posted by delta22 View Post
    Wow. That is very cool.

    Looks like a great liftoff.

    Is there any more info on this flight on the web?

    Google search on Medusa 88+1 gets some interesting results but nothing on this flight.
    You can find a build thread here. The text is in German, but the pictures should speak for themselves. Note that most of the thread is dedicated to Medusa I, which was destroyed in a fire (I believe before it could be flown). Medusa II is a rebuild, so details may vary. You will see that Andreas takes the "flash in the pan" concept quite literally. Surprisingly, the pan was nearly undamaged with only a few bright spots on the anti stick coating.

    Launch videos can be found here (1:42) and here in slow motion (0:45).

    Reinhard

  10. #40
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    ...Glad I found this before you launched. You seem to be making progress quite fast.

    I would call you crazy buttttttttt.... This is going to be too cool. You know what you are doing, where as I would have no idea to even start from.

    One question: In case something does goes wrong, you have a ton of motors and fire on your hands... Any plans safety wise?
    Last edited by Orion14ed; 30th October 2012 at 10:57 PM.
    || NAR Member #94750 ||| Junior Level One Madcow Patriot 4" H144 |||

  11. #41
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    Quote Originally Posted by Orion14ed View Post
    One question: How much water do you plan on bringing?
    We had Sandy bring some water to the field; in fact, she's still at it.

    In addition, the club has two pump and one pressurized bottles along with fire brooms and some training. We have more issues with cato incidents than we have with Boris's clusters.
    KENN BLADE
    NAR #80160
    CMASS President
    MMMSC Ambassador-at-Large
    NAR S&T Member

  12. #42
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    Quote Originally Posted by iter View Post
    I like the flame job on your Fatboy! It's remarkably similar to my Vulcan's--I wonder if I'm subconsciously following your pattern here. If yours homemade, from Stickershock or where?

    Ari.
    The flames are some very nice Stickershock vinyl decals.
    Boris Katan
    NAR / TRA L3
    Lots of fun cluster rocket pictures and video at: www.bpasa.com

  13. #43
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    Quote Originally Posted by Reinhard View Post
    You can find a build thread here. The text is in German, but the pictures should speak for themselves. Note that most of the thread is dedicated to Medusa I, which was destroyed in a fire (I believe before it could be flown). Medusa II is a rebuild, so details may vary. You will see that Andreas takes the "flash in the pan" concept quite literally. Surprisingly, the pan was nearly undamaged with only a few bright spots on the anti stick coating.

    Launch videos can be found here (1:42) and here in slow motion (0:45).

    Reinhard
    Thanks for the links, that slow motion video is awesome.
    Boris Katan
    NAR / TRA L3
    Lots of fun cluster rocket pictures and video at: www.bpasa.com

  14. #44
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    Quote Originally Posted by Orion14ed View Post
    ...Glad I found this before you launched. You seem to be making progress quite fast.

    I would call you crazy buttttttttt.... This is going to be too cool. You know what you are doing, where as I would have no idea to even start from.

    One question: In case something does goes wrong, you have a ton of motors and fire on your hands... Any plans safety wise?
    As noted in the first post:
    > one safety person with fire extinguisher to hose down booster
    > second safety person with RC control of additional deployment charge in case we don't like the direction of the flight
    > also Raven3 flight computer with multiple criteria that all must be OK before stage 2 fires

    > plus Sandy has wetted down the field
    Boris Katan
    NAR / TRA L3
    Lots of fun cluster rocket pictures and video at: www.bpasa.com

  15. #45
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    Quote Originally Posted by delta22 View Post
    As noted in the first post:
    > one safety person with fire extinguisher to hose down booster
    > second safety person with RC control of additional deployment charge in case we don't like the direction of the flight
    > also Raven3 flight computer with multiple criteria that all must be OK before stage 2 fires

    > plus Sandy has wetted down the field
    Let's hope the weather forecast for Saturday continues to improve. Earlier in the week they were calling for 19 mph winds. It's down to 12 mph now. A little less would be nice. What do you have for a top of the rail velocity?

  16. #46
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    Quote Originally Posted by billspad View Post
    Let's hope the weather forecast for Saturday continues to improve. Earlier in the week they were calling for 19 mph winds. It's down to 12 mph now. A little less would be nice. What do you have for a top of the rail velocity?
    The 31 Estes motors in the booster have a delightful thrust spike right at the start of the burn. The 19x D11 each have a max thrust of 27N and the 12x C11 each a max of 22N. Averaging thrust for the 0.2 seconds it will be accelerating up the rail, the cluster is pushing well over 600N, lifting the 12lb rocket at more than 12Gs. It should leave a 6ft rail at about 60ft/sec.

    The 12x C11s included in the first stage and 19x C11s in the second will accelerate the rocket quickly without sustained burns. Max velocity should be under 200mph and altitude under 1300ft.
    Last edited by delta22; 31st October 2012 at 01:37 PM.
    Boris Katan
    NAR / TRA L3
    Lots of fun cluster rocket pictures and video at: www.bpasa.com

  17. #47
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    Ran the Raven3 in simulated flight mode and successfully fired ematches for 2nd stage ignition, apogee and drogue as planned for the flight.

    The completed rocket will fly at 12lbs. A few shots of the rocket fully assembled.
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    Boris Katan
    NAR / TRA L3
    Lots of fun cluster rocket pictures and video at: www.bpasa.com

  18. #48
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    It's beautiful!

    Ari.
    2013 41,122Ns; 2014 27,030Ns; 2015 23,202Ns; 2016 16,474Ns

  19. #49
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    Quote Originally Posted by Reinhard View Post
    You can find a build thread here.

    You will see that Andreas takes the "flash in the pan" concept quite literally. Surprisingly, the pan was nearly undamaged with only a few bright spots on the anti stick coating.
    Huh. A cooking flash pan. I wonder if the German term carries the same pun. It looks like Andreas drills a hole in his pan for the J igniter. Also, I wonder if he uses any powder in the pan, or just lets the blast deflect from it and ignite the rest of the motors.

    Ari.
    2013 41,122Ns; 2014 27,030Ns; 2015 23,202Ns; 2016 16,474Ns

  20. #50
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    How did he get the pink smoke before liftoff?
    Matt, Tripoli #14257
    L1 11/13/16
    L2 2/25/17
    L3 Spring 2018....
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  21. #51
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    Quote Originally Posted by iter View Post
    It's beautiful!

    Ari.
    Thank you. Fortunately the red flame decals and red painted NC matched perfectly.

    Quote Originally Posted by iter View Post
    Huh. A cooking flash pan. I wonder if the German term carries the same pun. It looks like Andreas drills a hole in his pan for the J igniter. Also, I wonder if he uses any powder in the pan, or just lets the blast deflect from it and ignite the rest of the motors.

    Ari.
    Ideally for motor ignition something that throws hot particles is most effective, this needs to happen for a couple tenths of a second before the rocket starts to move up the rail. Definitely need BP powder in the flashpan to fire all the BP motors.

    In the slow motion video of the launch you can see the big red J come up to pressure with a dramatic red flame after all the BP motors have already started pushing hard and moving the rocket quickly up the rail.

    To reduce the risk of a delayed AP motor ignition in a cluster, I prefer to use CTI/AMW/ProX motors with the built-in BP quick pressurization pellet. Many of these motors will actually start pushing hard 0.1 to 0.2 seconds before the BP motors.

    While many folks believe that BP motors are instant on, examining slow motion video or Estes' published thrust curves show that they take about 1/4 sec to start pushing hard.
    Boris Katan
    NAR / TRA L3
    Lots of fun cluster rocket pictures and video at: www.bpasa.com

  22. #52
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    It looks fantastic. Best of luck on the launch. Video with good sound will be taken I hope.
    John

    NAR 92621
    TRA 17131
    Level 2

  23. #53
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    Quote Originally Posted by Rocket86 View Post
    It looks fantastic. Best of luck on the launch. Video with good sound will be taken I hope.
    HD video on the rocket, from a tripod near the pad and from the spectator's view. Also digital stills.
    Boris Katan
    NAR / TRA L3
    Lots of fun cluster rocket pictures and video at: www.bpasa.com

  24. #54
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    HellBoy 50 flew early in the afternoon on 11/3/12. The weather was mostly sunny, about 50F and windy.

    The first stage flashpan fired all 31 engines in the booster in a big cloud of smoke and a trail of flames.

    The rocket weathercocked severely due to the windy conditions and being overstable, becoming more horizontal than vertical at about the time the second stage was due to fire. Because of the safety conditions set for the Raven, the second stage did not fire.

    As the rocket continued to arc over and started to drop while traveling horizontally, both the drogue and main were deployed by the Raven at about 400ft altitude.

    The first stage was dramatic and the flight was safe.

    As a planned precaution, Bill Spadafora used the RC control to fire the safety ejection charge after the chutes deployed to clear that charge before the rocket touched down.
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    Boris Katan
    NAR / TRA L3
    Lots of fun cluster rocket pictures and video at: www.bpasa.com

  25. #55
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    Unfortunately, due to the speed the rocket was traveling when the chutes deployed, the onboard video camera (Boostervision HD Gearcam) was separated from the rocket. It had been taped to the rocket very near where the Kevlar recovery harness caused a slight zipper in the HellBoy.

    Thanks to Bill, Ken and several other folks who were kind enough to help look for the video camera. Despite looking for the camera for over an hour, it was not found.

    I will post the other video from this flight tomorrow.

    The HellBoy (sustainer) still has its 19x C11 motors and second stage flashpan ready to go. Igniter is removed, of course.
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    Boris Katan
    NAR / TRA L3
    Lots of fun cluster rocket pictures and video at: www.bpasa.com

  26. #56
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    CMASS has its last launch of the season in two weeks....

    I plan to fix the small zipper on the sustainer, and re-use the inter-stage coupling part of the booster with a new pack of engines and fins, and try this flight again...

    BUT the booster will be loaded with all C11 engines and MORE of them, at least 40 motors in the booster.

    This will allow for the rocket to get off the pad faster and the second stage to be fired at 0.9 seconds, reducing the opportunity for the rocket to weathercock.
    Boris Katan
    NAR / TRA L3
    Lots of fun cluster rocket pictures and video at: www.bpasa.com

  27. #57
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    Cool photos, and good job on making the safety call. I wish you fuller success next flight!

    Ari.
    2013 41,122Ns; 2014 27,030Ns; 2015 23,202Ns; 2016 16,474Ns

  28. #58
    troj's Avatar
    troj is offline Wielder Of the Skillet Of Harsh Discipline, Potentate of Perilous Pans TRF_ADMIN.png
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    Nice job, Boris; too bad you weren't able to stage it.

    Quote Originally Posted by delta22 View Post
    Bill Spadafora used the RC control to fire the safety ejection charge after the chutes deployed to clear that charge before the rocket touched down.
    I vote we blame it all on Bill.

    -Kevin

  29. #59
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    Quote Originally Posted by delta22 View Post
    > Use of Raven logic to prevent 2nd stage ignition if safety criteria are not met. From the Raven manual: "A deployment channel is triggered when all of the checked flight events are true."
    1) Set timer to 1.8 sec
    The other three logic settings are the safeties:
    2) Vertical speed > safety threshold (80% of sim)
    3) Altitude > safety threshold (80% of sim)
    4) Baro pressure decreasing (going up)
    All four logic conditions must be true at the same time for the second stage to fire.
    When you look at the sim data can you tell which conditions were not met for the second stage ignition, and what the values were?

  30. #60
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    Quote Originally Posted by troj View Post
    I vote we blame it all on Bill.
    If it was going to fail I was hoping it would do it earlier so I could feel like a real RSO and terminate the flight.

    We'll know better when Boris gets the data out of the Raven but I think it did what was best. From my point of view it looked like the rocket was horizontal or close to it at first stage burnout. That would have resulted in a power prang or a swamp landing or both.


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