More Q-Jets

Discussion in 'Propulsion' started by jqavins, Sep 19, 2019.

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  1. Sep 20, 2019 #31

    Nytrunner

    Nytrunner

    Nytrunner

    Master of Rivets

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    Additional manual steps add to the cost per unit significantly.

    And making/buying new industrial machinery to do those fiddly steps is a non-negligible investment
     
  2. Sep 21, 2019 #32

    georgegassaway

    georgegassaway

    georgegassaway

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    A motor with an Avg N-sec of 10, burning for 2 seconds, would be a 20 N-sec "D". If you want a "real" A10, then it would burn for 0.25 second at most (2.5 N-sec for A class, divided by 10 Newton Avg thrust).
     
  3. Sep 21, 2019 #33

    solid_fuel

    solid_fuel

    solid_fuel

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    I’m fine if they come out with 18x100 and longer motors.
     
  4. Sep 21, 2019 #34

    Wallace

    Wallace

    Wallace

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    Estes 13mm A3-4T being a "full" A is a pretty cool motor in the right application. Would certainly be cool to up the 13mm game if it makes economic sense. Don't see it happening though...
     
  5. Sep 21, 2019 #35

    Alan15578

    Alan15578

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    For some definition of "full". I find the A3-4t nearly useless, and I would fly many nore A3-2t and A3-6t motors, if they were still available.
     
  6. Sep 21, 2019 #36

    jlabrasca

    jlabrasca

    jlabrasca

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    I was wondering if somebody was going to correct me on that. >smile< I would like everyone to pretend that it was a typographical error.
     
  7. Sep 21, 2019 #37

    Initiator001

    Initiator001

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    The C10, C4, B7 (and maybe the D3) motors were designed and developed at AeroTech back when Ed LaCroix still owned Apogee.

    Ed wanted a smaller 'C' motor for Eggloft so the C10 motor was developed.
    A longer-burn C4 motor for gliders was another specialty motor for Apogee developed by AeroTech.
    These were both 18mm diameter motors but less than two inches long.

    Ed really wanted a 13mm diameter motor.
    The largest performance we could get out of a 13mm phenolic case would be a 'full' 'B' motor.

    The B7 was a real challenge.
    Scott Pearce spent a lot of time with Gary Rosenfield developing that motor.
    Getting the 13mm casing was not an issue.
    Creating a nozzle for the motor WAS an issue.
    Ed didn't want to spring for a nozzle mold and AeroTech had no use for a 13mm nozzle.
    Solution: Scott took 18mm nozzles and machined each one on a lathe to the size needed for the B7 motors.
    It took him all day to make 100 of the nozzles.
    Casting the propellant was another challenge as the propellant was difficult to pour into such small casting tubes.
    Scott and Gary eventually figured it out.
    Making the small diameter delays for the motors was not easy either.

    Eventually, the first batch of B7 motors was created by AeroTech.
    The motors were NAR certified with -4, -6, -8 and -10 second delays.

    Those were cool motors. I still have several in my collection.
    I used two of the B7 motors as a cluster in a 'C' eggloft event at a NAR meet.
    Scott developed a special two-headed Copperhead igniter for clustered B7s.
    The igniter worked great! I messed up by forgetting about drag-separation as the egg capsule came off the rocket at motor burn-out.
    Qualified but last place.

    Later, Ed would come up to AeroTech and do the final assembly of the B7 motors.
    The propellant/delay would have already been cast and the nozzles made.

    All the Apogee composite propellant motors were produced at AeroTech by AeroTech staff or later with Ed LaCroix handling some of the final assembly work. I was gone from AeroTech when Ed sold Apogee to Tim van Milligan so I don't know how/who made these special motors at that time.

    That's the story of the origin of the Apogee composite propellant motors.
     
  8. Sep 21, 2019 #38

    Charles_McG

    Charles_McG

    Charles_McG

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    I have a stash of Centuri 13mm B4s. A B7 would be a fine thing. It’s a nice upgrade over an A for a small but draggy rocket. I wouldn’t say a 13mm C would be overkill - but they are little rockets, after all.
     
  9. Sep 21, 2019 #39

    beeblebrox

    beeblebrox

    beeblebrox

    8 C6-0, 12 D11-9, 20 D20-0, 20 E5-0, 3 Cinerocs

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    The B7 was not designed by a third party, I designed that motor along with Gary Rosenfield when I was working for AeroTech. I still have one from the first batches. They were produced by AeroTech Initially, and later by contract by Apogee. I also designed a B14 & C26 but there was no interest from AeroTech to make those...
    1.jpg 2.jpg 3.jpg
     
  10. Sep 21, 2019 #40

    Alan15578

    Alan15578

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    THanks. I guess you are the "third party" I referred to.
     
  11. Sep 21, 2019 #41

    Alan15578

    Alan15578

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    Thank you very much for the development history of those motors. I knew the story started with Ed LaCroix when he owned Apogge. Tim continued the operation and even added some contest BP motors, and Tim stopped making or having the motors made after the AT fire and relocation.
     
  12. Sep 21, 2019 #42

    Rocketjunkie

    Rocketjunkie

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    There was briefly a 13mm C6. I had a few when they were available. White Lightning, moon burner. I had a cato and the pieces show the liner was peeled down 10.5mm body tube. It was longer than a A3, iirc about 60 mm. Wish I still had some but they probably would be impossible to light.
     

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