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  1. #1
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    Lightbulb Please Post Your Drogueless Descent Rates Here.

    When Jolly Logic released the Chute Release, John Beans requested that people would post their drogueless decent rates so we can perhaps learn about what is a realistic decent rate for OR (and possibly RockSim) simulations. To date, nobody has in that thread. So, Let's make it easy to find. Please post your decent rates here.

    We need to know what your kit's specs are (.ork or .rkt sims help), and how it performed after separation.

    Thanks!

    Dreaming of making the rockets I dreamed of as a kid (and then some).


    NAR L1 Cert flight: Sheridan, Oregon, USA. Sept. 19, 2015. Flew Deep Space OFFl on an I357T-14A Blue Thunder

  2. #2
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    26th November 2009
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    Quote Originally Posted by K'Tesh View Post
    When Jolly Logic released the Chute Release, John Beans requested that people would post their drogueless decent rates so we can perhaps learn about what is a realistic decent rate for OR (and possibly RockSim) simulations. To date, nobody has in that thread. So, Let's make it easy to find. Please post your decent rates here.

    We need to know what your kit's specs are (.ork or .rkt sims help), and how it performed after separation.

    Thanks!
    Uhhhhhh, Me thinks a lot of folks are flying the chute release without any additional electronics. That said, I agree it would be interesting for those that have a recording device along for the ride post their descent rates. That of course would
    depend on the rocket and the size of the reefed chute packet. A good sized reefed chute may act as a pseudo streamer of sorts. Kurt


  3. #3
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    A few data points from my two BAR Crayon kits (both about 40 oz loaded, 4" diameter, nose break):
    Drogueless with 48" bundled Spherachute ~40-45 ft/s (2 flights)
    12" drogue at nosecone with 48" bundled Spherachute-40 ft/s, much more stable descent and more responsive main deploy (3 flights now)
    15" drogue at nosecone with 50" bundled Top Flite ~35 ft/s (1 flight)

    While the drogueless rate and rate on the drogue are about the same, I'd definitely recommend a drogue on anything heavier than a Leviathan or so, just to stabilize the descent. With no drogue, the Crayon oscillates between the nose leading the booster and the booster leading the nose, and also drifts more horizontally ("side gliding"). With the drogue descent is much more stable and vertical. That said, drogueless is really nice on light rockets to simplify recovery.
    Last edited by SCrocketfan; 31st May 2016 at 06:41 PM.
    NAR Jr. L1-2014, Tripoli TMP (L2 hopefully in early 2017)
    "If at first you don't succeed, you must be flying rockets"-Stanley Knapp

  4. #4
    Join Date
    28th November 2014
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    Indiana
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    Flew a Estes Mammoth today with a Chute Release and Alt3, almost 1100ft, see Alt3 graph...

    edit: drougueless decent = ~38ft/s, on 24" chute ~20 ft/s.

    Click image for larger version. 

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    Last edited by dhkaiser; 1st June 2016 at 02:35 AM.

  5. #5
    Join Date
    22nd May 2014
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    Most of my flights with the chute release have included the a Jolly Logic II and some tracker (mostly BRB900) so I don't have a drogue descent rate for those flights.

    However, the Lava Laguna is a night rocket with 4 NiteBows, 2 fore and 2 aft so I have to use a RRC3 to separate it at apogee and until now had used cable cutters to deploy the main. With the Chute Release, the setup was so easy even with a 50" Top Flight chute and paralite.

    Accoding to the LCD on the RRC3 the drogueless descent rate was 51 fps (and main at 22 fps). See OR and mDACS screen caps below.

    Click image for larger version. 

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    Miles A.
    TRA# 14639 - NAR# 95695
    L1 - Polecat Aerospace Spike - CTI H133 - 04-27-13
    L2 - "Tubula Rasa" - CTI J270 - 08-24-13
    L3 - Mad Dog 6 "Blue Moon" - CTI M1670 - 10-25-14
    Ns Burned 1969-2012 < 100
    Ns Burned 2013 - 11,983
    Ns Burned 2014 - 30,585
    Ns Burned 2015 - 49804.5 (17268 at NARAM 57)
    Ns Burned 2016 - 46268
    Ns Burned 2017 - 28943.4

    "It is by caffeine alone I set my mind in motion. It is by the beans of Java that thoughts acquire speed, the hands acquire shakes, the shakes become a warning. It is by caffeine alone I set my mind in motion." - The Programmer's Mantra

  6. #6
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    5th June 2010
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    Great thread!

    If anyone knows their flight weights, those would be good to list, too. Many people get nervous when they have a 5 pound or 9 pound rocket, and worry about the tumble rate.

  7. #7
    Join Date
    15th May 2016
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    Ballpark weights, all were with payload bays and about 15' cords. I have video of the Screech and villain falling with no drogue if anyone's interested.


    6 pound 4" rocket






    3" 6 pound MAC villain. This guy comes in HOT.



    5 pound 4"


    The rest of these only graph G load :/ Unless I can't figure out the MARSA software.

    nine pound 3"


    3" Villain 6 pound





    The following 4 are from my 2.6" screech, 7.5 pounds loaded, so ballpark 6 ish burnout?
    k1127


    J510W


    K1127 (ok I posted this, looked at it stupid and then realized it blew the main at 8700' ><

    J1026 LC




    Hope these help. I like drogueless, and think it's fine if you're balanced right and the rocket isn't coming in ballistic dragging the NC behind it.
    Last edited by DavidMcCann; 1st June 2016 at 05:53 AM.
    David McCann
    Dave's Rockets | My Flights
    URRG |URRF 4| Level 2 | TRA# 14210

  8. #8
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    Quote Originally Posted by John Beans View Post
    Great thread!
    I though you'd get a kick out of it.

    Thanks to everyone who's posted their statistics. This is going to help a lot of people!

    Pointy Side UP!
    Dreaming of making the rockets I dreamed of as a kid (and then some).


    NAR L1 Cert flight: Sheridan, Oregon, USA. Sept. 19, 2015. Flew Deep Space OFFl on an I357T-14A Blue Thunder

  9. #9
    Join Date
    13th February 2016
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    Gilroy, CA
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    Estes PSII Nike Smoke

    Estes Pro Series II Nike Smoke. AeroTech RMS 29-40/120 with a G76-10G reload. Generally stock build, added a light parachute shelf and replaced the estes shock cord with a 10' of 900# tubular Kevlar. Weight was about 17 oz without the motor. Had both the JLCR and a JLAltimter3 attached to the chute and nosecone. Stock 24" chute.
    Descent Rate without a drogue was about 41 ft/sec. (1319 ft / 32 seconds) = 41.2

    Click image for larger version. 

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  10. #10
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    Videos at realtime speed, just for giggles- Yellow rocket is the Villain, Blue/green is the Screech. I've got no problem popping these guys at 80 fps, and pretty sure thats the speed my 9 pound DS is falling as well. Chutes for the screech and villain are 4' Rocketman or 48" fruity chutes Iris. DS is on the iris.

    Villain (3 flights)-
    https://youtu.be/mXfD646uURc
    https://youtu.be/euJD8tX0Sew

    Screech (2 flights)-
    https://youtu.be/rCW0Ot4SfFw
    Last edited by DavidMcCann; 1st June 2016 at 05:55 PM.
    David McCann
    Dave's Rockets | My Flights
    URRG |URRF 4| Level 2 | TRA# 14210

  11. #11
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    13th February 2016
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    Estes Pros Series II Mega Der Red Max

    Rocket: Estes Pro Series II - Mega Der Red Max
    Build Details: Stock plus small eyebolt in fwd CR with short length of Kevlar and a swivel inside body tube to prevent shock cord wind up during droguless descent using the JLCR.
    18" Nomex Chute Protector. Weight also includes the JLCR and a JL Altimeter 3.
    Notes: This setup falls slowly, and the booster with the big fins falls in horizontal orientation and spins quite a lot when falling without the chute.
    Weight w/o Motor: 36.3 oz

    Weight with a G80-7T as flown in the video and plot below: 40.8 oz

    Droguless Descent Rate: 33 ft/sec

    The chute took a few seconds on open in the plot below.. and as you can see.. the chute only slowed it down a little more than the droguless descent rate.
    Will Ferry posted a nice video with zoom where you can see the droguless descent and also the chute release let go.. then the chute take a few seconds to open. Here's a link:

    https://photos.google.com/share/AF1Q...95Q1ppZ1RzQXdR

    Click image for larger version. 

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    Last edited by kevinkal; 1st June 2016 at 06:42 AM.

  12. #12
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    3rd February 2012
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    I've flown a number of smaller rockets drogueless (wouldn't do it with anything above 3#...), and the typical descent rate is 40-50 fps. That seems to be about what everybody else sees, too. You want the rocket to break roughly in the middle, and the pieces should weigh about the same. Something light and large like a Partizon would probably come down slow enough drogueless that if the main didn't come out you'd probably get it back unharmed.

  13. #13
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    I and many people I know routinely fly 6-15 pounders drogueless, Any reason you suggest 3 pounds? Larger rocket, larger chute, absorbs the speeds just fine to me.
    David McCann
    Dave's Rockets | My Flights
    URRG |URRF 4| Level 2 | TRA# 14210

  14. #14
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    Quote Originally Posted by DavidMcCann View Post
    I and many people I know routinely fly 6-15 pounders drogueless, Any reason you suggest 3 pounds? Larger rocket, larger chute, absorbs the speeds just fine to me.
    I absolutely agree. Even larger is fine. A large rocket in a flat spin can fall slower than the same rocket under a drogue. A drogue usually prevents a flat spin. Unfortunately, I don't know how to reliably cause flat spins.


    Steve Shannon
    Steve Shannon
    L3CC, TAP, Director, Tripoli Rocketry Association

  15. #15
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    Name the rocket "maverick"
    David McCann
    Dave's Rockets | My Flights
    URRG |URRF 4| Level 2 | TRA# 14210

  16. #16
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    Quote Originally Posted by DavidMcCann View Post
    Name the rocket "maverick"



    Steve Shannon
    Steve Shannon
    L3CC, TAP, Director, Tripoli Rocketry Association

  17. #17
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    Quote Originally Posted by DavidMcCann View Post
    I and many people I know routinely fly 6-15 pounders drogueless, Any reason you suggest 3 pounds? Larger rocket, larger chute, absorbs the speeds just fine to me.
    It's size (cross sectional area) vs. weight. Most larger rockets have a disproportionately larger amount of weight, mainly because they're usually fiberglass vs. cardboard. That means that their drogueless descent rate will be higher. Does it mean that it's unacceptably high? Probably not, but I tend to be a little conservative in these matters.

  18. #18
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    Quote Originally Posted by cerving View Post
    It's size (cross sectional area) vs. weight. Most larger rockets have a disproportionately larger amount of weight, mainly because they're usually fiberglass vs. cardboard. That means that their drogueless descent rate will be higher. Does it mean that it's unacceptably high? Probably not, but I tend to be a little conservative in these matters.
    and usually proportionally bigger fins. I Don't have a CR, so no dog in this fight, but I wouldn't have an issue dropping a ten pounder with one using motor deploy and and no traditional altimeter.
    David McCann
    Dave's Rockets | My Flights
    URRG |URRF 4| Level 2 | TRA# 14210

  19. #19
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    17th November 2015
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    Don't have descent data but here's a video of my Wildman Punisher popping a CR'd chute at apogee then opening at 300(I think? Maybe 400?) It was a windy day so the flight arced a bit near the top. Even with the CR, it was about 1/3 of a mile (on a 1500' apogee). Spun like CRAZY on the way down, but that didn't seem to hurt anything.

    Will post more data when I finish building my Eggtimer. SMTs are HARD.



    (Side note - watch the clouds after it lands. Doing that was fun)

  20. #20
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    David, great data! Thanks.

  21. #21
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    This IQSY Tomahawk was coming down really fast (over 150 fps, is that too fast?) until JLCR released the chute exactly at 500 feet for a nice landing. Weight was 3480g with the I-500 motor (2900g with no motor).
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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    L1 3/25/17 H135
    L2 8/12/17 J180

  22. #22
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    I only fly one rocket drogueless, that's a 3" LOC tube scratch built that weighs about 4 lbs.

    I have no problem flying a JLCR on a motor eject because the bundled chute works like a drogue and controls the decent.

    I do have a problem with flying large DD rockets without a drogue and allowing the majority of the flight, apogee to main deploy, to be flown with NO control of the flight profile. Chaos will eventually get you! Sure, a well balance rocket will drop right without a drogue, until it doesn't. Without a drogue to set and control the flight profile during the drop, there is nothing to prevent the main from deploying under the fin can and everything come crashing down.

    I know flying HPR is all about risk management. If you are OK with risking a crash on a 15 lb rocket because the drop from apogee didn't happen the way it had the previous 5 or 10 flights that's OK. The risk of injury is probably super small, the risk of damage to the rocket might be higher, but still acceptably small.

    I've just seen too many failures or near misses because of drogueless flights that I won't do it except on small DD flights. Again, risk management.

    BTW, just because the LCO says congrats and great flight over the PA, doesn't mean the flight wasn't a near miss. </rant off>
    Handeman

    TRA #09903 L3 3/29/2015

    "If you don't use your head, you have to use your feet!" my Dad

    Tripoli Central Virginia #25 - BattlePark.org

  23. #23
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    19th February 2017
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    Recently flew my scratch Vesta on a G80. Standard LOC 1.6" tube, ply fins. 1lb loaded, like 12ish oz w/o motor. 40" long. That thing left in a hurry!

    Very similar to a beefy Estes Star Orbiter.

    vesta-camera.ork

    Anyway, estimated drogueless speed 50ft/s.

    Last edited by LithosphereRocketry; 26th October 2017 at 11:30 PM. Reason: Added OpenRocket sim
    NAR #104043

    crmrc.org

  24. #24
    Join Date
    22nd January 2009
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    Palo Alto, CA
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    My L record rocket had 150 feet/second descent rate. The CTI 6XL 75mm case is pretty substantial.


    http://www.rocketryforum.com/showthr...567#post243567

    L3L Oct9 2011.FIPa
    Adrian Adamson
    Featherweight Altimeters LLC
    www.featherweightaltimeters.com

  25. #25
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    21st September 2017
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    PML BumbleBee flying on J270W motor, 22530g / 5.0 lbs.
    Hit 3572" altitude (lower than simmed, due to suspected weak motor that finished burn earlier than the projected 2.6 secs).
    At apogee, ejection charges deployed JLCR folded 48" chute that had stabilized descent rate to 52 fps. 48" folded chute / semi-streamer descent rate is functionally equivalent to that of a 12.5" drogue chute, per OR simulation.
    Once JLCR release at 300", the descent rate slowed down to 21 fps.

    Click image for larger version. 

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    a
    __
    Radrocketeers.org NAR L2

  26. #26
    Join Date
    17th November 2015
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    I have some really good and unique information to add!!
    My "Mega Vector Force" had an Altimeter 3 in it when it failed to deploy. Dry weight is about 1400g. With a failed deployment, its initial descent rate was 130 fps; ground hit was at 190 fps.* Since this is a stable rocket with a heavy nose and nice big fins, I'd think it just arced over gracefully at apogee and came straight at the ground.

    With the altimeter 3 in place and a successful deployment with the Chute Release set to 400', initial descent was 63 fps and ground hit was at 22.7 fps.
    In OpenRocket, I have a "faux drogue" parachute to simulate the post-break tumble that I've now tweaked so that it will give me that descent rate. My rocket is 1.78m long; lower section is 57.5 mm, upper section is 39.5mm.

    *sidebar - a shout-out to Always Ready Rocketry; the fin can and a good chunk of airframe was quite usable after that crash)


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