AeroTech Open Thread

Discussion in 'Propulsion' started by ATGM, May 16, 2015.

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  1. Dec 7, 2019 #3,211

    Rocketjunkie

    Rocketjunkie

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    I had the last J99 cato Aerotech replaced the casing but wouldn't replace the reload. They had me choose an equal value in other motors. The cato ejected the forward closure. I glued in the forward closure and flew the other J99 I had. It worked Glad to see it coming back :)
     
  2. Dec 8, 2019 #3,212

    boatgeek

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    Forgive me if this is answered elsewhere, but is it legal (ie within manufacturer's instructions and therefore not a research motor) to remove the BP ejection charge from a Q Jet motor? I have a saucer that I like to fly on Q Jets but the shortest delay is still long enough that it has landed by the time the ejection charge goes. I would much rather peel back the red caps, dump the charges into my BP can, and not risk starting a fire on the ground.

    Thanks!
     
  3. Dec 8, 2019 #3,213

    BEC

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    I have been known to remove part of the BP from a Q-Jet (especially the early ones that had KILLER ejection charges). It certainly makes sense to do as you suggest.

    I know that doesn’t exactly answer your question. If I were the LCO or RSO at the launch I’d certainly be OK with it as I think doing what you suggest for the reason you suggest it outweighs technically “modifying” the motor.
     
  4. Dec 9, 2019 #3,214

    beeblebrox

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

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    Geeeezzz, just do it already and be done with it. If someone dimed you out for that, then THEY need to find another hobby and stop nit pickin'
     
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  5. Dec 9, 2019 #3,215

    jetlag

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    I'd like to know why there are no more G80-4's. Indeed, any SU G80. Are the G79,78,77's just as good?
     
  6. Dec 9, 2019 #3,216

    rcktnut

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    I don't believe the G80's are discontinued, they are now considered DMS all with 14 sec. adjustable delays. They used to be in the Hobbyline category with the various delays. The G80's have a considerably higher total impulse than the others you listed.
     
  7. Dec 9, 2019 #3,217

    Steve Shannon

    Steve Shannon

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    In my opinion there’s nothing wrong with that. One of the scariest fires I’ve seen was started by an ejection charge on the ground.
     
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  8. Dec 9, 2019 #3,218

    dpower

    dpower

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    I routinely remove ejection charges from AT SU motors when using in saucers, pyramids, etc. Then put in a little super lube, and put the cap back on.
     
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  9. Dec 10, 2019 #3,219

    John Taylor

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    They are available just expensive!!!
     
  10. Dec 10, 2019 #3,220

    jnelson

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    They're available in 7, 10, and 13 second lengths, plus the DMS version
     
  11. Dec 10, 2019 #3,221

    Theory

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    yea they are! really hard to justify the price
     
  12. Dec 10, 2019 #3,222

    bronicabill

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    That's good information to know! While I haven't flown enough MPR to experience a defect in my AT stuff, now that I'm jumping back into it with a new build, it is good to know somebody covers warranty issues when "user error" is not the problem!
     
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  13. Dec 10, 2019 #3,223

    emckee

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    Sometimes I wish Aerotech would be a bit more selective on the warranties that they do honor, or that we, as users of the equipment and reloads, would be more honest with ourselves as to whether the issue was really, truly a problem with the hardware or reload... Yes, it stings when $200 in hardware and reload go up in smoke, potentially destroying your $500 project with countless hours of labor invested, but as Rick mentioned, there are a lot of "user error" issues on assembly that lead to motor failure, and because they're difficult to show conclusive evidence one way or another, AT will typically honor the warrantee, even if it may be or is likely a user error. That's great, except for the fact that they need to cover the cost of the warrantee replacements... Nothing is free, after all. So ALL USERS end up paying for all of those warrantee replacement hardware bits and reloads in the form of increased prices.

    One option, would be to simplify the assembly of the motor - I believe this is the direction AT was going when they released the RMS-EZ reloads, where the delay assembly was fully assembled. However, we all know how that ended up. Another option would be to put some serious effort into making the instructions provided with each reload more accurate and easier to understand for those who may not be used to the way the motors go together. But then you have the problem of those people (including myself) who don't always use the instructions because "I've build this reload dozens of times"... It's difficult to make something idiot-proof - they keep inventing new kinds of idiots. :)
     
  14. Dec 11, 2019 #3,224

    Andrew_ASC

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    Just bought an L1000W and threw AT H-130W
     
  15. Dec 11, 2019 #3,225

    emckee

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    Throwing motors is not recommended. :p
     
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  16. Dec 11, 2019 #3,226

    RobCamele

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    I recently burned an AT J180T with normal motor function. When I attempted to clean the motor hardware, after it cooled, I discovered that the phenolic liner was essentially welded or melted to the inside of the motor casing and can not be removed. I did use a generous coating of Super Lube on the outside of the liner when I assembled the motor about an hour before the flight and I'm certain that I followed the assembly instructions correctly. I've never had this happen before and was wondering if anybody else has. Does anybody know any procedure for removing the liner in this situation without damaging the hardware or am I just going to have to buy a new 54/852 case?

    IMG_0376.jpeg
     
  17. Dec 11, 2019 #3,227

    Rocketjunkie

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    Here's a copy of my post in the J180T problem thread. I make D grain reloads for Aerotech cases and this is the method I use to remove stuck liners. I do not grease liners in Aerotech or CTI motors.

    You greased the liner, now it's glued in. The C-slot core allows heat build up on the side with the slot.You will need a seal disk without O-ring, some WD40 or other penetrating oil, and a piece of wood dowel at least 1" diameter.
    Apply WD40 to both ends of liner and allow it to suck in between liner and case. Let sit for at least an hour. Insert seal disk into one end of liner. Put other end of case on a soft surface and push out the liner using the wood dowel. If it still won't move, use a hammer on the wood to get it started moving, then push it out. You can use steel wool to get the remaining gunk out of the case.
     
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  18. Dec 11, 2019 #3,228

    jd2cylman

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    Gently heat the case in an oven (less than 200°) or with a heat gun on a moderate setting. Then grab the case with a oven mitt and push the liner out with a seal disc and a stick.
    The last three I burned at LDRS, I did not grease the liners.
     
  19. Dec 11, 2019 #3,229

    Cory

    Cory

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    I like the seal disc on a stick...but prefer a well lubricated liner...just personal preference.
     
  20. Dec 11, 2019 #3,230

    John Taylor

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    Lube the liner,.... wait, don't lube the liner,.... you need to lube the liner,.... no way am I gonna lube the liner........
    ...........which is correct???
     
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  21. Dec 11, 2019 #3,231

    Nytrunner

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    Yes :cool:

    *I joke. This is one of the many beautiful facets of rocketry where there is no single right answer. In such cases you can ask 3 people and get 4 answers. Maybe the best answer I've gotten to these situations is "Try both, see what works best for you"
     
  22. Dec 12, 2019 #3,232

    Banzai88

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    And the really funny thing about that piece of advice is that you'll do it one way for 3 burns, and the 4th time it'll be all different, all over again!
     
  23. Dec 12, 2019 #3,233

    BradMilkomeda

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    I always try to remove the linear and remnants ASAP after the flight. IMHO it might have prevented this stuck situation.

    I wonder if their are people who swear by delaying the clean up is easier.:music1:
     
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  24. Dec 12, 2019 #3,234

    ATGM

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    The G80 is offered in the 14 second adjustable format as a DMS motor as well as 7, 10 and 13 second delays. The G80 is the most powerful of the G's that you listed so you're gonna get a bigger push.
     
  25. Dec 12, 2019 #3,235

    ATGM

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    You can leave out the BP and then the delay element will become a nice smoke element. You could also go with backup motor ejection along with your electronics.
     
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  26. Dec 12, 2019 #3,236

    John Taylor

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    Smart flier!
     
  27. Dec 13, 2019 #3,237

    ChicagoDave

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    I’ve also noticed that it is easier to remove the liner as soon as practicable. Once I left a liner in until I got home from a launch and it took me 3 days to extract it.

    Since then I extract as soon as I can. Gloves help to hold the hot casing.
     
  28. Dec 13, 2019 #3,238

    Arsenal78

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    Does Aerotech have plans to make a G64-6? 8 is too long for some rockets and 4 is too short. Flew a PML Mini BBX on a G64-4 and it was too short (needed a 6). Being quantum there was no damage but how long will that last?
     
  29. Dec 13, 2019 #3,239

    dmgrime

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    This is the RMS for the 29/40-120 case yes? Assuming yes, buy the -8 and use the delay drilling tool to take it down to 6.

    I tend to always buy the longest possible delay and then drill for the specific flight.

    If we are talking SU (non DMS), then this doesn't apply...
     
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  30. Dec 13, 2019 #3,240

    Andrew_ASC

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    Typo meant three. Anyways your comment made my day.
     
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