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  1. #151
    Join Date
    24th June 2013
    Location
    Raleigh, NC
    Posts
    18
    I didn't have my JLCR in time for my L1 cert, but I have flown in twice in my L1 cert rocket.

    The first time, I was flying with no vent hole in the airframe (having read it's not required), set the JLCR for 500', and watched it release with no tangles... shortly after hitting the ground. Fortunately, there was no damage.

    The second time, 45 minutes later, I drilled a 1/4" vent hole, and everything worked perfectly.

    My theory is that with a relatively small airframe volume and a tight nose cone, the pressure spike caused by inserting the nose cone interfered with the barometric value used for ground level. I would welcome additional input.

    L1: ARR Blue Phenix, I357, 9/23/2017 [USR Stiletto, H128, 1997]
    L2: Giant Leap Liberty 4, K550, Raven 3, 1/21/2018 [PML Sudden Rush, J350, ALTS2, 1999]
    L3: 1/2 scale Aerobee 150A, under construction

  2. #152
    Join Date
    11th February 2017
    Location
    south Florida
    Posts
    634
    Quote Originally Posted by Vombatidae View Post
    I didn't have my JLCR in time for my L1 cert, but I have flown in twice in my L1 cert rocket.

    The first time, I was flying with no vent hole in the airframe (having read it's not required), set the JLCR for 500', and watched it release with no tangles... shortly after hitting the ground. Fortunately, there was no damage.

    The second time, 45 minutes later, I drilled a 1/4" vent hole, and everything worked perfectly.

    My theory is that with a relatively small airframe volume and a tight nose cone, the pressure spike caused by inserting the nose cone interfered with the barometric value used for ground level. I would welcome additional input.
    Did your chute eject from the rocket? As the JLCR does not release the chute until after ejection, when it is in the open air, it's hard to see why a vent hole in the airframe would affect the JLCR's performance.

    That being said, in my experience the JLCR has likewise failed to release the chute until impact on at least 2 occasions out of 20 or so, not sure why.


    L1 3/25/17 H135 Wildman Darkstar Jr
    L2 8/12/17 J180 LOC Expediter
    L3 3/17/18 M1350 Painkiller Max

  3. #153
    Join Date
    24th June 2013
    Location
    Raleigh, NC
    Posts
    18
    Quote Originally Posted by billdz View Post
    Did your chute eject from the rocket? As the JLCR does not release the chute until after ejection, when it is in the open air, it's hard to see why a vent hole in the airframe would affect the JLCR's performance.

    That being said, in my experience the JLCR has likewise failed to release the chute until impact on at least 2 occasions out of 20 or so, not sure why.
    Yes, the bundled chute was out at apogee - made a pretty effective drogue.

    To elaborate on my theory, the pressure inside the airframe at the time of the first launch was probably significantly above the ambient ground level barometric pressure, and I'm speculating that could interfere with the 500' AGL detection.
    L1: ARR Blue Phenix, I357, 9/23/2017 [USR Stiletto, H128, 1997]
    L2: Giant Leap Liberty 4, K550, Raven 3, 1/21/2018 [PML Sudden Rush, J350, ALTS2, 1999]
    L3: 1/2 scale Aerobee 150A, under construction

  4. #154
    Join Date
    28th November 2014
    Location
    Indiana
    Posts
    332
    ...
    TRA #16452
    L1 Wildman Drago

  5. #155
    Join Date
    1st December 2012
    Location
    San Antonio, TX
    Posts
    164
    Quote Originally Posted by BryRocket View Post
    Here are some photos of the rocket I'm working on now. Its almost exactly the same design as the one from the video (I guess that ebay is at home after all). The runcam2 has worked out pretty good for me. No complaints. Let me know if you have any questions.

    Attachment 341703
    Attachment 341702

    Attachment 341706
    Attachment 341705
    Attachment 341704
    Did you print your own sled? Pretty slick setup you got there. I have been thinking of something similar from the same company (different lens) and wondered how the lens holds up without a shroud.
    In thrust we trust

  6. #156
    Join Date
    19th June 2017
    Location
    Austin TX
    Posts
    60
    Quote Originally Posted by Vombatidae View Post
    Yes, the bundled chute was out at apogee - made a pretty effective drogue.

    To elaborate on my theory, the pressure inside the airframe at the time of the first launch was probably significantly above the ambient ground level barometric pressure, and I'm speculating that could interfere with the 500' AGL detection.
    When did you turn on the JLCR and set the release elevation? That is when it would take the baseline reading Iíd assume. Iím guessing you did that before stuffing it into the rocket right? Are you thinking that, after you set the JLCR, when you pushed the nosecone in the rocket it raised the pressure and messed with the reading?


    Sent from my iPhone using Rocketry Forum
    NAR 102867
    L1 06/2017
    L2 08/2017

  7. #157
    Join Date
    19th June 2017
    Location
    Austin TX
    Posts
    60
    Quote Originally Posted by Performance nut View Post
    Did you print your own sled? Pretty slick setup you got there. I have been thinking of something similar from the same company (different lens) and wondered how the lens holds up without a shroud.
    The sled is from Andrew at Additive Aerospace. His stuff is awesome.

    The lens is great without a shroud. I epoxy a piece of polycarbonate to the back of the lens so I can mount it a few different ways.


    Sent from my iPhone using Rocketry Forum
    NAR 102867
    L1 06/2017
    L2 08/2017

  8. #158
    Join Date
    24th June 2013
    Location
    Raleigh, NC
    Posts
    18
    Quote Originally Posted by BryRocket View Post
    When did you turn on the JLCR and set the release elevation? That is when it would take the baseline reading I’d assume. I’m guessing you did that before stuffing it into the rocket right? Are you thinking that, after you set the JLCR, when you pushed the nosecone in the rocket it raised the pressure and messed with the reading?


    Sent from my iPhone using Rocketry Forum
    Exactly. I powered it up, got a solid green led at 500', and popped it in. I was first up on that rack, so it flew only a couple of minutes after arming.
    L1: ARR Blue Phenix, I357, 9/23/2017 [USR Stiletto, H128, 1997]
    L2: Giant Leap Liberty 4, K550, Raven 3, 1/21/2018 [PML Sudden Rush, J350, ALTS2, 1999]
    L3: 1/2 scale Aerobee 150A, under construction

  9. #159
    Join Date
    11th February 2017
    Location
    south Florida
    Posts
    634
    Quote Originally Posted by Vombatidae View Post
    Exactly. I powered it up, got a solid green led at 500', and popped it in. I was first up on that rack, so it flew only a couple of minutes after arming.
    Interesting theory but I doubt that is the reason the JLCR failed to release, hopefully John Beans will comment. After my first fail with the JLCR, someone suggested the cause was the lack of a vent hole in the airframe, but John told me no vent hole was needed. See also: http://www.rocketryforum.com/showthr...lease-Question (ejection charge pressure does not cause false reading).

    L1 3/25/17 H135 Wildman Darkstar Jr
    L2 8/12/17 J180 LOC Expediter
    L3 3/17/18 M1350 Painkiller Max

  10. #160
    Join Date
    18th January 2009
    Location
    Urff
    Posts
    6,845
    After spending a month exposed to sunshine, wind, and rain on Snow Ranch, my lost/found Chute Release charged up and works perfectly. It was enclosed in a Dino Chutes JLCR sleeve that faded from bright red to a pale orange also.

    Hats off to John Beans for crafting a very durable device.
    Cranky Kong, L2 Certified Rocket Monkey
    "But we were promised jet packs!"

    Total Impulse in 2018: 1,402.35 Ns (Equivalent to a 10% K motor.)
    Total Impulse since 2010: 15,274.46 Ns (Equivalent to a 49% N motor.)

  11. #161
    Join Date
    11th April 2017
    Location
    Brisbane Australia
    Posts
    711
    Quote Originally Posted by BryRocket View Post
    When did you turn on the JLCR and set the release elevation? That is when it would take the baseline reading Iíd assume. Iím guessing you did that before stuffing it into the rocket right? Are you thinking that, after you set the JLCR, when you pushed the nosecone in the rocket it raised the pressure and messed with the reading?


    Sent from my iPhone using Rocketry Forum
    Iíve heard this trigger the servo release in a JLCR when the nose cone went on - the other member couldnít figure out why he kept hearing the JLCR open in the pad while prepping and asked us what we thought was happening.

    Told him to vent the body and 30sec of cordless drill work later, JLCR worked flawlessly.
    Reasonably new to rocketry and hailing from the land down under.. I speak metric... I know not of these feet and inches you speak of...

    QRS: #193
    AMRS: #148

    AMRS L1 (2018-03-18 - Mk4 Rocket Propelled Companion Pod)

  12. #162
    Join Date
    23rd July 2011
    Location
    Butte, MT
    Posts
    2,557
    If youíre using motor deployment, put your motor in after putting on your nosecone so you donít cause a pressure spike by inserting the nosecone.

    Steve Shannon
    L3CC, TAP, Director, Tripoli Rocketry Association

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