Estes Avenger Body Tube Length

Discussion in 'Low Power Rocketry (LPR)' started by Swany, Nov 6, 2018.

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  1. Nov 6, 2018 #1

    Swany

    Swany

    Swany

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    I'm in the process of restoring what I thought was an original Estes Astron Avenger, but after a little digging I'm starting to wonder. The question is what should the length of the main BT-55 body tube be and what is the true overall length (with the booster) ? The original kit comes with a BT-55 tube that is 18" long, but if I add up the various components to get an overall length, it comes out to 33.75 inches: 2.75 (Booster) + 18 (Main BT-55 Body) + 1 (Exposed part of transition section) + 7.75 (BT-50 Payload Section) + 4.25 (PNC-50Y Nose cone). The Rocksim file I downloaded and the actual rocket I have has a 16 in. BT-55 Tube, which is closer to the advertised overall length of 32" in the old catalogs I have. Are you supposed to cut the 18" tube down to 16" ? I couldn't find anything in the instructions that says to do so. I'm sure I'm missing something basic...
     
    Last edited: Nov 6, 2018
  2. Nov 6, 2018 #2

    kuririn

    kuririn

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    Per John Brohm's Estes body tube reference, the upper main tube is a BT-55V at 16.35". The face page of the instructions lists the overall length as 32.25". It is possible that an original kit was supplied with a tube that varied from the correct length. It's been known to happen, not only with Estes but other manufacturers as well.
     
  3. Nov 6, 2018 #3

    Leo

    Leo

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    I have an original from the late 70's built and it measures 18" body tube.
     
  4. Nov 6, 2018 #4

    kuririn

    kuririn

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    P.S.: The original K-38 instructions from JimZ's website lists that as part# BT-55V. I also found an addendum regarding this kit in appendix 1 of John Brohm's reference, excerpted below:

    4) K-38 Avenger
    The instructions for the K-version have the illustrations for Part D (BT-20J) and Part E (BT-20M) reversed; BT-20J was the longer part at 2.75”, while the BT-20M was 2.25” long.
     
  5. Nov 7, 2018 #5

    Swany

    Swany

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    I think I have figured it out with help from input from this thread. The original issue of the Avenger (K-38 kits) used the BT-55V, but I think around 1975, Estes switched to the 1238 Kit number and a standard 18” BT-55. Thanks for the replies !
     
  6. Nov 10, 2018 at 6:03 AM #6

    mwtoelle

    mwtoelle

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    They switched to a full length BT-55 when Estes made the change to the PNC-50Y for the nose cone. The ARCAS (K-26/1226) was probably switched at around the same time. Estes was probably trying to save some money by not having to carry the BT-55V.
     

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