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  1. #1
    Join Date
    18th June 2014
    Posts
    123

    2.6" Competitor 2 Stage - Configuration

    I just finished up my 2.6 Competitor 2 stage built. I'd like a bit of a sanity check to make sure I don't make any stupid mistakes, this is my first 2-stage HPR.

    Here is the Openrocket file : Red Tenacity - 2 stage.ork

    I plan to fly it with DMS H550 (0.6s burn time) in booster and a Loki H160-LB (w/pyrodex pellet) in the sustainer. Setup is as follows.

    Booster
    Eggtimer Quantum #1 (Drogue Channel) - separation charge at 0.7s,
    Eggtimer Quantum #1 (Main Channel) - chute deploy at apogee
    motor backup @ 7s

    Sustainer
    - Sustainer ignitor will be handled by Quantum #2 in middle ebay via conduit through MMT centering rings into bottom of motor as per normal launch, wire will be twisted and taped to allow break during drogue deploy
    Eggtimer Quantum #2 (Drogue Channel), airstart @ 1s after launch, altitude minimum (none), velocity minimum 100ft/s
    Eggtimer Quantum #2 (Main Channel), drogue deploy @ apogee
    Eggtimer TRS (Drogue Channel), drogue deploy @ apogee + 1s
    Eggtimer TRS (Main Channel), deploy @ 500ft

    My sim shows sustainer ignition @ 1s will be at height 156 ft, velocity 216 ft/s.

    For pad setup, I'll bring it up to the pad with both ignitors out
    - load the booster on the rail, arm the Quantum #1 via wifi and insert motor ignitor
    - load the sustainer on the booster (ignitor out)
    - arm eggtimer TRS
    - insert ignitor in sustainer
    - back off, ensure area is clear and arm Quantum #2

    Screenshots of the SIM & OR screen showing weights/motor selection.

    Click image for larger version. 

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    Click image for larger version. 

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    Thanks for any help/advice you can offer.

    cheers - mark


  2. #2
    Join Date
    22nd August 2015
    Location
    Rhode Island
    Posts
    1,284
    Lots of us are trying to use Eggtimer Quantum’s for staging. Please tell us how it works out.

    I don’t have the the manual in front of me right now, but I’m wondering if you can set the minimum altitude to 100 ft. I think the minimum value in the software is 300 ft. (I hope I’m wrong about that.)

    NAR #100940, RIMRA & CMASS
    L1 - 4/17/16, Tyrannosaur (by Binder Design), Loki H144
    L2 - 8/19/17, Terrordactyl (by Binder Design), CTI J250

  3. #3
    Join Date
    18th June 2014
    Posts
    123
    Quote Originally Posted by BDB View Post
    Lots of us are trying to use Eggtimer Quantum’s for staging. Please tell us how it works out.
    I don’t have the the manual in front of me right now, but I’m wondering if you can set the minimum altitude to 100 ft. I think the minimum value in the software is 300 ft. (I hope I’m wrong about that.)
    You are correct, I misread the manual. 300ft min, and min speed is 100ft/s change by 100ft/s. I'll edit my first post to reflect these changes.

  4. #4
    Join Date
    22nd August 2015
    Location
    Rhode Island
    Posts
    1,284
    But that creates the problem. According to your simulation plot, you won't be over 300 ft when you want to light the sustainer. I'm having some of the same issues with my simulations and I know one other TRF member here is too. We have both had the sustainer not light because we didn't exceed the minimum altitude for the safety lockout. I want to make this work for MPR and low HPR, but it seems like it's a matter of go big or go home (or build a MD 2-stage rocket that will stage above 300 ft on a G or H motor).
    NAR #100940, RIMRA & CMASS
    L1 - 4/17/16, Tyrannosaur (by Binder Design), Loki H144
    L2 - 8/19/17, Terrordactyl (by Binder Design), CTI J250

  5. #5
    Join Date
    18th June 2014
    Posts
    123
    Quote Originally Posted by BDB View Post
    But that creates the problem. According to your simulation plot, you won't be over 300 ft when you want to light the sustainer. I'm having some of the same issues with my simulations and I know one other TRF member here is too. We have both had the sustainer not light because we didn't exceed the minimum altitude for the safety lockout. I want to make this work for MPR and low HPR, but it seems like it's a matter of go big or go home (or build a MD 2-stage rocket that will stage above 300 ft on a G or H motor).
    Yes, I'll set the altitude minimum to 'OFF' to avoid that problem. It'll still have the velocity check of 100ft/s as a safety. I'd have to bump to booster up to an i500T (380ft) or larger to be able to use the altitude minimum check.

  6. #6
    Join Date
    22nd August 2015
    Location
    Rhode Island
    Posts
    1,284
    Good point. This is one of the cases where it makes sense to only use velocity as the safety lockout.
    NAR #100940, RIMRA & CMASS
    L1 - 4/17/16, Tyrannosaur (by Binder Design), Loki H144
    L2 - 8/19/17, Terrordactyl (by Binder Design), CTI J250

  7. #7
    Join Date
    29th December 2013
    Location
    Bayport MN
    Posts
    167
    Be sure to check your launch detect altitude.

    Sent from my LG-V521 using Rocketry Forum mobile app
    L1 - Madcow 4" Phoenix I180 Skidmark 1651 feet
    L2 - Darkstar 2.6" J145 Skidmark longburn 4787 feet
    L3 - Terminator 5" M1297 White Lightning 8602 feet

    TRA 15743
    NAR 30949
    http://www.rocketreviews.com/karl-tyrrells-page.html

  8. #8
    Join Date
    18th June 2014
    Posts
    123
    Okay, I put the whole shebang together last night and here is the final setup for flight on Saturday :

    Booster
    - H550ST, delay 7 seconds
    - Quantum Drogue - nose over (1g) for parachute
    - Quantum Main - timer - 0.7s (5g) for separation charge

    Sustainer
    - Loki H160 w/pyrodex pellet, 12 second delay
    - TRS Main - 500 ft (1g)
    - TRS Drogue - Nose-over + 1s (1g)
    - Quantum Drogue - Nose-over (1g), 2 sec pulse
    - Quantum Main - air start, timer 0.9s, min velocity 100ft/s, 2 sec pulse

    The main only has one charge as the Quantum can't do an altitude release when in airstart mode. I may drop a Quark in there in the future to have a redundant main. The drogue has 3 charges, so that should get out for sure.

    If that flight goes well, I'll fly it again on Sunday with an I500/H90Red.

    If it doesn't go well I'll delete this post and pretend it never happened

    cheers - mark

  9. #9
    Join Date
    18th January 2009
    Posts
    1,888
    Good luck on your project. I haven't studied it in any detail, but I have a couple of comments (if I'm off base, just delete and pretent it never happened).

    I think your general timing seems a bit quick. With a motor burn of 0.6 seconds and a separation charge at 0.7, it doesn't seem like it would take much for the two events to overlap. Why not allow a little coast and then also be able to use an altitude check? I'd separate at 1 second and light at 2.

    I'm not familiar with the quantum, but why would you use a 2 second pulse? If this is the altimeter latch time, I always try to use the shortest possible time in case the igniter shorts.

    I'd put in the booster igniter last.

    I would also recommend an all-up test of the electronics before loading the sustainer. With the igniter out and the rocket vertical, turn on all the electronics and make sure the igniter doesn't fire. Turn everything off, load the rocket and go. You want to do everything you can to ensure the sustainer won't fire on the pad, even if you back off before arming the Quantum.

    Jim

  10. #10
    Join Date
    18th June 2014
    Posts
    123
    Hi Jim,

    Thanks for your comments. I welcome your advice!

    Quote Originally Posted by JimJarvis50 View Post
    I think your general timing seems a bit quick. With a motor burn of 0.6 seconds and a separation charge at 0.7, it doesn't seem like it would take much for the two events to overlap. Why not allow a little coast and then also be able to use an altitude check? I'd separate at 1 second and light at 2.
    I reread the Quantum documentation and Cris suggests burn time + 20%, so 0.7 is a little quick. I'll bump it to 1 second. My sim shows velocity at 216ft/s at 1s, 196ft/s at 1.5 and 180ft/s at 2s. I thought it would be best to get the sustainer lit as soon as possible, that's why I set it at 0.9s. I'm also not sure how fast the sustainer will start and get up to pressure, so I figured sooner is better than later?

    If I change the sim to 1s separation and 2s ignition, it drops the altitude by about 100ft. I'm not going for altitude, so this doesn't bother me. I just want to make sure the rocket is pointing up when the sustainer lights!

    Okay, I ran the sim again. Even if I light at 3s, it is still going 142ft/s, which should still be fine. I'm going to change it to 1s separation, 2s ignition.

    Quote Originally Posted by JimJarvis50 View Post
    I'm not familiar with the quantum, but why would you use a 2 second pulse? If this is the altimeter latch time, I always try to use the shortest possible time in case the igniter shorts.
    2 seconds is the default on the Quantum. From the Quantum airstart manual, Cris gives the settings for his flight, he used a pulse time of 4 seconds. Also according to the Quantum manual, it should survive a short from the igniter. I have redundancy on the Drogue and the Main is handled by another computer, so even if the Quantum craps out after sustainer ignition I should be okay.

    Quote Originally Posted by JimJarvis50 View Post
    I'd put in the booster igniter last.
    I would also recommend an all-up test of the electronics before loading the sustainer. With the igniter out and the rocket vertical, turn on all the electronics and make sure the igniter doesn't fire. Turn everything off, load the rocket and go. You want to do everything you can to ensure the sustainer won't fire on the pad, even if you back off before arming the Quantum.
    Sounds like a good plan, I'll alter my checklist to match.

    cheers - mark

  11. #11
    Join Date
    18th January 2009
    Posts
    1,888
    I'm not sure if you're pyrodex pellet is something you're adding or built into the motor, like CTI. If it's built in, ignition would be fast. If you're adding it, then who knows. Pyrodex pellets burn pretty fast. I don't use them any more, but when I did, I would fill the center hole with epoxy to slow down the burn a little. Now, I use dipped ematches using the PML magnelite. It works quite well.

    I see the 1-9 seconds for the firing time. Not sure why that is (maybe Cris can explain the philosophy of that), but I guess it doesn't hurt anything. Just for reference, I typically use 0.1 seconds for ematches.

    Jim


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