What Body Tube Fits A 6'' Parachute?

Discussion in 'The Watering Hole' started by Matt_The_RocketMan, Sep 11, 2019.

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  1. Sep 11, 2019 #1

    Matt_The_RocketMan

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    I would like to know if an alpha, wizard rocket can comply with 6 in parachutes.
    Body tube wise would be nice to know.....
     
  2. Sep 11, 2019 #2

    Eric

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    I don't necessarily think body tube has much to do with parachute size. It's more dependent on your total rocket weight after motor burnout for deciding if a parachute will give you an acceptable descent rate.
     
  3. Sep 11, 2019 #3

    Matt_The_RocketMan

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    But would a 6" support a alpha rocket flying on a 1/2 A6-3?
    or would it be better for a smaller rocket like Viking or Wizard?
     
  4. Sep 11, 2019 #4

    ebruce1361

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    The Alpha is a BT50 (24mm I.D.) and the Wizard is a BT20 (18mm I.D.). Both are lightweight enough, that a six inch parachute should be okay. The Alpha will descend faster due to being heavier, but I wouldn't call that a problem since a full 12 inch parachute like what comes in the kit will make it drift for a while.

    If you've ever flown any of the Estes "3 Bandits" rockets, that'll give you an idea of how Wizard will behave on a 6 inch parachute. Personally, I like streamers better for these little rockets, but the chute still works.
     
  5. Sep 11, 2019 #5

    Nytrunner

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    Matt, you've called yourself a 'rocket commander', 'team leader', and 'rocket expert/wiz' in several previous posts on here.

    Taking into account the very basic questions you've been asking also, I think you need to study some more on the fundamentals of rocket design and rocket performance, as well as gain some experience using simulation software before you call yourself any of those again.
    You will benefit from the research, as will any team you find yourself in charge of.
     
  6. Sep 11, 2019 #6

    Steve Shannon

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    Matt,
    The simple answer is yes, a six inch parachute can fit into those rockets as long as you fold them correctly and use a chute made of the right fabric. But that’s not how chutes are matched to rockets. You match them according to the weight and descent speed you want.
     
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  7. Sep 11, 2019 #7

    BABAR

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    Tagging onto this, WHAT is the goal for your recovery device? Sounds like in your case, you may want to swap out a streamer for a chute. WHY?

    Generally goals ranked as follows.

    1. Safety. The first thought is: "Is the recovery device BIG enough to slow down the descent so it doesn't hurt anyone or break anything it lands on?" But you also need to think: "Is this device likely to be successfully deployed? e.g., maybe I can get an 18" chute in a BT-5 but how likely is it that the ejection charge is going to actually get it OUT of the rocket?!" There is a term for a chute or streamer that is too big to be deployed. It is called "ballast."

    2. Will the device slow the rocket down enough that the rocket doesn't break? A lot of this depends on rocket design, particularly fins. Airfoiled fins, rear swept fins (classic Alpha), and fancy fins and landing gear (Mar Snooper), anything built by @neil_w , may benefit from a larger chute and a softer landing than something like an Estes Viking built with fins swept FORWARD. (my bias is showing, I LOVE forward swept fins both because they look cool and because when rocket lands usually the motor casing hits and takes brunt of impact before fins get involved with the ground.)

    3. Speed. As funny as it sounds, once you accomplish 1 and 2 above, in most cases aside from duration competition events you want the rocket to get back to earth as otherwise quickly as possible to save you a long walk or a lost rocket. The most advanced form of this (I think) is Dual Deploy, send that puppy way out beyond visual range, blow the nose and maybe a drogue, let it drop slightly slower than a rock, then deploy the main at a few hundred feet up. This minimizes drift, decreases the number of steps you get on your FitBit, and increases probability rocket will come home with you. This (and the challenge of packing a big chute loosely enough that it will reliably deploy) is why you do not want too LARGE a chute.

    4. Coolness factor. Some types of recovery are in the eyes of some beholders cooler than others, examples include tumble, glider, helicopter, airbrake recovery, magnus, horizontal spin, featherweight...... there are certainly others I don't know about and likely some that haven't been invented yet.
     
    Last edited: Sep 11, 2019
  8. Sep 11, 2019 #8

    neil_w

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    Also depends on what your launch fields are like. Mine are usually pretty soft farmland, so I err on the side of smaller chutes, except for designs more likely to be vulnerable to landing damage (i.e. APRO Lander II).

    That said, those smaller chutes will not serve me well if the rocket finds the road for its landing. I keep my fingers crossed. :)
     
  9. Sep 12, 2019 #9

    Matt_The_RocketMan

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    That is exactly why i am asking more experienced people, who have used 6" parachutes, I am preparing the team for up coming comp. . I wouldn't say its a bad thing to ask questions?
    Overall I like to ask for opinions, wisdom and knowledge saves money and time on my hand...
     
  10. Sep 12, 2019 #10

    Eric

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    Flying even the basic and most simple rocket even a few times will answer all your basic parachute needs questions.

    There is no simple answer to what size parachute will work with your rocket. There are several things to take into account.

    And yes. There are some bad questions. That's why there is a search function as well as Google.
     
  11. Sep 12, 2019 #11

    Matt_The_RocketMan

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    I would say, you guys are like google, but you already know the topic (rocketry) so I mean, I have never used a 6" parachute, with any rocket. I believe asking a person rather than a PC is bound to give you answers that are more likely to help the person asking them.
     
  12. Sep 12, 2019 #12

    Eric

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    In all my rocketry. I have never used a 6-inch parachute. That is very small. How many grams does your rocket weigh?
     
  13. Sep 12, 2019 #13

    kuririn

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    I have heard 15 fps as a good rule of thumb for descent rate.
    Much slower than that and your rocket might drift out of sight.
    Much faster than that and you might be harvesting pieces of your build.
    Here's a link to a descent rate calculator. Just enter weight of your rocket (with expended casing) and size and shape of your chute. https://www.rocketreviews.com/descent-rate-calculator.html
    I think a streamer might work just as well for the tiny rockets as a 6" chute.
    Laters.
     
  14. Sep 12, 2019 #14

    AfterBurners

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    And since you are using plastic chutes I would suggest sprinkle some talcum powder on the chute so it opens more easily.
     
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  15. Sep 12, 2019 #15

    kuririn

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    Yes, they do exist. Pulled one from my spare parts pile. I think it came with a mini engine RTF kit, but don't remember which one. I probably subbed a streamer for it for faster pre-flight prep.
    Cheers.
    IMG_20190911_135927.jpg
     
  16. Sep 12, 2019 #16

    BABAR

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    I think the Estes Tercel Pod has a 6 inch chute
     
  17. Sep 12, 2019 #17

    Matt_The_RocketMan

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    I actually own one 6" parachute, i don't know that ill be using it any time soon.
     
  18. Sep 12, 2019 #18

    Charles_McG

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    Those little black Estes chutes never open for me. I have better luck with streamers.
     
  19. Sep 12, 2019 #19

    Matt_The_RocketMan

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    I would like to know if cutting a spill hole in a 6" parachute would defeat the purpose of the chute, when used with a Alpha Rocket
     
  20. Sep 12, 2019 #20

    Nytrunner

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    2 effects:

    How much area will you remove from the chute? You may end up with the equivalent of a 5.5 or 5" chute

    Air will vent out of the middle instead of spilling out the sides. This will stabilize the descent slightly. (In some cases, the parachute will fall slower because it doesn't periodically dump all its air)
     
  21. Sep 12, 2019 #21

    neil_w

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    I cut spill holes in most of my plastic chutes to stabilize descent. In this case you are taking a tiny chute and making it tinier... but if a smaller effective size is OK then go for it.
     
  22. Sep 12, 2019 #22

    ebruce1361

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    Spill holes (also known as apex vents in some cases) are good features to have for larger parachutes because like Nytrunner said, it can improve stability. However, in the case of an Estes Alpha, if you're already wanting to use a 6" parachute, that's half the size of the parachute that comes with the kit. At this point, you'll likely get too much descent speed and could break a fin or two. With Alpha III rockets, the fins are one plastic piece, so those do just fine on even a streamer because they usually bounce upon landing, but a regular Alpha has rigid balsa fins that need that extra drag coming down. If anything, you can use a regular 12" parachute and cut the middle half out so you'll get approximately the same descent speed as a 6" parachute without the wobble, but with how little drag the 6" chute will offer to begin with, wobble might not be that big of a deal given the mass of the rocket.
     
  23. Sep 13, 2019 #23

    Flyfalcons

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    I have had nothing but bad luck with 6" Estes chutes. They never open consistently, no matter how I pack them. The 9" works much better.
     
  24. Sep 13, 2019 #24

    Matt_The_RocketMan

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    Yeah for my Competition on Sep 21st we are required to use 6" parachutes, when all our gear is fitted with 12". So i guess I am going to have to do some back tracking on the newer rockets we built, and install the 6in parachutes... Hopefully this Saturday I can make some adjustments and try out my only 6" with a alpha rocket..
     
  25. Sep 13, 2019 #25

    ebruce1361

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    I am not familiar with a competition involving 6" parachutes. I know about duration competitions using the biggest streamers or parachutes one can fit in a rocket, but the idea there is to big, not small.
     
  26. Sep 13, 2019 #26

    Matt_The_RocketMan

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    Yeah, they want 6" I was questioning the comp when they also wanted 1/2A6-3 engines, but a competition is a competition and we abide by the rules... Just fyi these are competitions held and run by AFJROTC Units, they have at least 3 NAR refs there...
     
  27. Sep 13, 2019 #27

    ebruce1361

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    Maybe that's why I've never heard heard of it. I am not versed in any JROTC competitions for rocketry. Do you have a link you could share?
     
  28. Sep 13, 2019 #28

    Matt_The_RocketMan

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    Ill get a PDF for you to look over, Ill also try to share some pics of recent comp i went to...
     
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  29. Sep 14, 2019 #29

    Matt_The_RocketMan

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  30. Sep 14, 2019 #30

    Matt_The_RocketMan

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    Hopefully this will answer all questions and doubts....
     

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