Odd C6-5's

Discussion in 'Propulsion' started by Karl, Apr 21, 2019.

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  1. Apr 21, 2019 #1

    Karl

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    I was opening a couple packs of C6-5's earlier to top my launch box up and noticed that the motors were physically different. One pack had the usual 'grey' nozzles that I'm used to but the others were completely white. They are also filled to different levels despite both being the same engine. Any ideas why that would be?
     

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  2. Apr 21, 2019 #2

    Lukun7

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    That's strange. I once had a C6-5 with the BP ejection charge showing at the top. Maybe these motors were made with a bad batch of clay. It should still fly, though
     
  3. Apr 21, 2019 #3

    Lukun7

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    Do the motor cases look the same or have the same writing on them? If not, Estes may have given you something that they didn't mean for you to have.
     
  4. Apr 21, 2019 #4

    djs

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    I’ve had this before- there’s some small variation in how everything is packed. All the motors performed nominally.
     
  5. Apr 21, 2019 #5

    hcmbanjo

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    The whiter nozzles are older.
    I always thought the darker, gray speckled nozzles might be made using compressed kitty litter.
     
  6. Apr 21, 2019 #6

    djs

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    The dark spots are where they ran out of the new stuff and had to go fishing for the raw material out of the cat box :)
     
  7. Apr 21, 2019 #7

    Zeus-cat

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    Hopefully not used kitty litter.
     
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  8. Apr 21, 2019 #8

    Rex R

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    variations in BP ingredients, not all charcoal is the same. with each shipment Estes has to test and adjust their engines to keep them to meet the thrust curve, one batch of bp may provide more thrust than other batches so they adjust the amount used (and nozzles), as well as other factors to keep the motors in spec.
    Rex
     
  9. Apr 21, 2019 #9

    cavecentral

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    The light one is likely pure bentonite clay. The grayer ones with the chunks are likely mixed with grog (pottery shards). This helps it bite into the cardboard wall better when pressed.
     
  10. Apr 21, 2019 #10

    djs

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    If you get the right kind of used kitty litter, it’s kind of like a hybrid motor?
     
  11. Apr 21, 2019 #11

    dhbarr

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    Wrong kind of ammonia :-D
     
  12. Apr 21, 2019 #12

    Karl

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    Thanks for the heads up. I presumed it was some change in manufacturing process or manufacturer that caused the difference.
     
  13. Apr 21, 2019 #13

    BABAR

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    Grog and rocketry May not be best mix.

    Sort of like the old pilot rules, don’t smoke within 12 hours of the flight and don’t drink within 100 feet of the aircraft.
     
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  14. Apr 21, 2019 #14

    Eric Jimenez

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    Yup, I once opened a really old kit and it had those white nozzles. They performed the same as the current ones.
     
  15. Apr 21, 2019 #15

    lakeroadster

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    Hold my Grog... I got this!
     
  16. Apr 23, 2019 #16

    shreadvector

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    If the nozzles are extremely white, they are "Poopy Clay" and they will erode when fired. The erosion can be uniform, resulting in a larger nozz-hole and lower thrust, or the erosion can be asymmetrical, resulting in vectored thrust. Either variation will result in bad flights or crashes.

    If the nozzles are not extremely white (like talcum powder) and just look like concrete, then they are fine. The original motors from the 1970s and 1980s had the concrete looking clay. Around the time of Star Wars Episode 1, they switched to the "Poopy Clay" which was very , very bad. After enough reports from consumers, they then switched to the "Strong Like Ox" clay which has a mottled appearance and does not erode at all.
     
  17. Apr 23, 2019 #17

    Jim Hinton

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    Hi Folks;

    I would guess then that the E9 motors were equipped with the 'super poopy can't wait to get out of here' clay nozzles? I'm not sure of the color, one usually sees them blasted all over the deflector.

    Jim
     
  18. Apr 23, 2019 #18

    rharshberger

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    E9 were the same clay as all the other currently made motors from Estes. It was the peopellant having issues causing overpressuring.
     
  19. Apr 23, 2019 #19

    Jim Hinton

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    Bummer, I liked the wimpy clay story better. But I guess if you're going to insist on being technically correct...
    Just kidding of course. They always had a lot more issues with their larger BP motors. I flew a number of E9's but I never had one blow out the nozzle. Just lucky I guess.

    Jim
     
  20. Apr 24, 2019 #20

    RoyAtl

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    Estes has used different clays in the past. The white stuff Fred Shecter (ShredVector) calls "poopy clay". Not exactly sure why, except he says they resulted in weaker nozzles (and more catos).

    The clay before that was grainier but a consistent gray color, unlike the clay since which has had that mottled appearance, but definitely seems tougher. Back when Centuri had their own motor machines in the early 70's they experimented with a clay mixed with the grindings from their Enerjet graphite nozzles. The clays used in the German manufactured motors for MRC and Quest had a shiny metallic ingredient (maybe graphite, maybe not), and the clay used in MRI/MPC/AVI/FSI 18mm/Quest self made motors was white (and softer). The Chinese motors for Quest had a harder reddish clay.

    Amateurs often use compressed kitty litter (usually bentonite clay) for their nozzles
     
  21. Apr 24, 2019 #21

    BEC

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    Some pictures might help. These are all B6-4s. The one on the left is from the period that used what Fred referred to as "poopy clay". The date code on this one 17Q11 - November 17, 1986. I have examples with nozzles like this from the very early 1980s to the early 1990s. The second one is like the one in the first post. This one is dated 033001 - so March 30, 2001. The one on the right is much more recent - June 19, 2015.

    I have some "poopy clay" motors whose nozzles haven't needed any exhaust to erode....they come apart of their own accord (and so these motors get soaked and discarded). But generally they work well enough at least in low-value rockets.

    I don't know when E9s first appeared and therefore whether or not they overlap the "poopy clay" period which runs, based on motors I have on hand, from around 1982 through 1993 or so.
     

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