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  1. Coop

    30" chute with hole on top vs. 24" standard chute?

    As Terry said, spill holes (AKA Apex Vents) will increase stability --and up to a certain point, performance as well. How you'd size them entirely depends on the Cd of the chute. Flat chutes --like the plastic jobs that come in Estes kits-- are poor performers with Cds in the range of 0.65...
  2. Coop

    3/4 Mercury Redstone

    Last 2 bags are done --there was a shipping delay because local post office hasn't figured out how to navigate a field of the Pennsylvania state flower... Later! --Coop
  3. Coop

    4 inch diam / 29 mm ??

    2.25 lb? 3 or 4 grain H will give you a decent ride. Heaviest I've flown on a 29mm was my 6.8lb Phoenix-- CTI 6XL 29mm white. I-243? Is that right (no worries; someone'll correct me if it ain't)? puts that up in the high 1400's or so... Later! --Coop
  4. Coop

    Equinox - reducing two chutes to one?

    30" seems... excessive for a rocket that light, but if the 30" has as low a Cd as the pair of 18's, it may be about equal in performance. Not being familiar with the 30" you mentioned, I'd ask about its opening characteristics, if your expected ceiling is only 500'. I'd think a smaller...
  5. Coop

    What is the weight limit for streamer recovery?

    A lot of those calculators made odd assumptions about streamer size and material and Cd that may or may not line up with reality. Where they may serve as a guide, I'd expect some trial and error to achieve desired results. Not saying they're useless--merely to proceed with caution and due...
  6. Coop

    What is the weight limit for streamer recovery?

    Thanks, Les! Later! --Coop
  7. Coop

    What is the weight limit for streamer recovery?

    Most I, personally, ever recovered on a streamer as primary recovery was in the neighborhood of 5 lbs. That was on a QRS-36. Streamers really excel at apogee events in traditional dual-deploy setups. Makes it much easier to visually track. I used them on both my L2 and L3 cert flights...
  8. Coop

    3/4 Mercury Redstone

    I cannot help but note that the vast majority of people who do rocketry AT ALL will never make a rocket with a diameter equal to or larger than the center core of those grains. Very very impressive, sir. Later! --Coop
  9. Coop

    Custom rings and fins needed

    Upscale CNC is still taking orders. I emailed him recently --said he may be busy for a week or so upcoming, therefore, I would encourage patience, but he has always been very good at getting back to customers. He's made a few things for me. Later! --Coop
  10. Coop

    3/4 Mercury Redstone

    I'm still blown away by the component sizes of this thing--and that, for its size, is surprisingly light. I cannot wait to see it all together. Later! --Coop
  11. Coop

    3/4 Mercury Redstone

    Thanks so much! I made one or two Higgs flights since we moved there last fall, but have missed a couple due to work schedule--on night shift now, and often switch up to do a 24-hr shift, so I have to commute fewer days per month--and the schedule with the kids has been a little nuts --read...
  12. Coop

    3/4 Mercury Redstone

    Like the rest of TRF, I've been enjoying this build thread immensely, and thought it was an insane project in the very best way since I first learned of it. I would never state that I know what the world needs at any given point in time, but I'm pretty extra-special sure that an amateur-built...
  13. Coop

    Thrust to Weight & Getting Off The Pad Calculation

    If concerned, one can reach out to the club before loading up the car and see what rail lengths are available... if an 8-foot won't do, inquire about the availability of a 10, if that will suit. Or secure your own that's compatible with their particular mounting system and bring it with...
  14. Coop

    Vacuum Chamber on the Cheap

    Interesting! I fabricated a vacuum chamber for altimeter testing --merely verifying operation with christmas tree lights in place of ejection charges-- by stretching a nitrile glove over the top of a plastic cup, securing with a rubber band, and pulling the fingers until I saw the apogee light...
  15. Coop

    Chute Release Again!!!

    Yes it is. Had it downloaded to my phone and able to show the RSO by the time I returned from where the rocket had landed. I cracked the case and screen on the next flight... still got data. And on the flight after that. I used the chute release 5 times, had perfect operation 4 of them...
  16. Coop

    Chute Release Again!!!

    I just giggle myself stupid when I realize I got flight data off of a 1.6 diameter LPR rocket zooming to the extreme altitude of 533 feet on a mighty D-12 black powder motor. And yes, that is a dual-deploy profile, courtesy of the Chute Release. Later! --Coop
  17. Coop

    Chute Release Again!!!

    Not only are there lower opening speeds, our shroud lines are much shorter than any skydiving rig, thus do not have the length to build up friction heat as they're pulled across the canopy. Consider: even larger hobby chutes are typically packed in a bag. The ones that the JLCR will typically be...
  18. Coop

    R.I.P. Mega Der Red Max

    What I have done in the past with good success is use the dremel with sanding disks stacked to appropriate thickness. Short work of the slots.... or one of the dremel bits of the correct thickness.... Merely a suggestion. Later! --Coop
  19. Coop

    CTI reload does not fit into casing, help please

    I have run into this a few times over the years--not often enough to fret about, but I do keep some sandpaper in my range box just in case... Later! --Coop
  20. Coop

    Shock cord stuck on fin?

    I have video of this occurring on my Hellraiser flight. I puzzled at the cause, until I got the flight data. Primary altimeter failed to detect apogee. Therefore, rocket had an appreciable amount of forward speed at separation when the back up charge fired two seconds later. This slightly late...
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