LOC? Kit.

Discussion in 'High Power Rocketry (HPR)' started by Jarhead, Mar 21, 2020.

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  1. Mar 21, 2020 #1

    Jarhead

    Jarhead

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    6950A2E6-C8E0-44A7-83C8-9F746EBB316A.jpeg I was gifted a built kit and haven’t done much with it. Now that we are staying close to home I’m going to get it ready to fly.
    Maybe a LOC lot but not sure.
    Not fiberglass. 5.5 inch diameter. 90 inches long. 6 fins. 7 x 38mm motor mounts.
    Any ideas? And does anyone have the RocSim file?
    Thanks in advance!
     
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  2. Mar 21, 2020 #2

    Speaknoevil

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    @ECayemberg is an expert on big LOC clusters and, although he doesn't use Rocksim (does his calcs on his own), he can probably identify the rocket.
     
  3. Mar 21, 2020 #3

    3stoogesrocketry

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    That is a loc ultimate max . If you wanna sell it , let me know .

    Eric
     
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  4. Mar 21, 2020 #4

    LOC

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    That is exactly what it is. I'm not sure how long it's been out of production. But, I do know we haven't made any since 3.0 took over. And the reason is as follows... Find out what motors you plan on using, and check their aft thrust ring diameter... You may have a difficult time fitting all 7 motors. Old school kits were designed around HPR motors that didn't have that. You wrapped masking tape and friction fit just like low power so the tubes could all be stacked together. Now the motor companies are making aft rings that we're all familiar with, and these old cluster kits may, or may not work. Some say sand the motor thrust ring down, But I can't speak to that. I've never tried...
     
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  5. Mar 22, 2020 #5

    Rocketjunkie

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    I have one. 38 mm reload cases fit fine. However, I did build it in the time of SU motors and I have to friction fit the motors. If I were building it now, I'd put threaded inserts between the motor tubes for retention. Here it is flying on a J350 and 3 38/240 Rx H130s. The J350 took its time coming up to pressure so the air started outboards (at about 1/2 second) lit at the same time.
     
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  6. Mar 26, 2020 at 11:26 PM #6

    DeeRoc29

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    Interesting timing. just finished mine!
     

    Attached Files:

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  7. Mar 27, 2020 at 12:51 PM #7

    Theory

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    yall know im not a cluster guy, but i would absolutely pick (if i could) one of these up and get in the game.

    a trio of I357's would be cool for the smaller east coast fields, and should also be easy to light.
     
  8. Mar 27, 2020 at 8:07 PM #8

    Rocketjunkie

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    With the stock kit, the rear centering ring has 7 (touching) holes. 3 of the motor tubes are much longer and the front centering ring has 3 in line holes. The 3 tubes are long enough to handle 38-6GXL cases in the short tubes. This allows 3 motors to provide motor ejection. I put a solid bulkhead in mine for electronic ejection only and none of the motors have to withstand the pressure of ejection, only enough not to fall out when the shock cord reaches full extension. I do still have an extra pair of centering rings in case I have to do a rebuild. It does have a fin flutter problem so I added a single layer of 4 oz glass tip to tip on the fins. Built before rails became common, if flies off a 1/2" rod.
     
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  9. Mar 27, 2020 at 9:01 PM #9

    DeeRoc29

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    I felt obligated to put 1/2" lugs on mine, and included buttons just in case. I also put in a bulkhead above the mmt like you did, Tom. I hope we get to drag race our UM's someday!
     

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    Last edited: Mar 27, 2020 at 9:25 PM
  10. Mar 30, 2020 at 1:42 AM #10

    Performance nut

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    I made a similar cluster not long ago. Here are my lessons learned:
    • Use single use motors. You will have to trim thrust rings some. Be careful how you do this or you may compromise the thrust ring and end up with a motor launching tube. I had 5 engines. The center engine was not trimmed, the outer engines were notched to accept the center.
    • It will get unholy hot in the aft area. All my motor nozzles, aft body tube, and aft thrust ring was significantly toasted. I recommend against air starting motors due to the heat likely burning your igniter wires before they light. Mine were 5 G80T's if you want to reference power and heat.
    • I staggered my ejection charges on three engines in the event I had engines that didnt light or if I did not achieve separation.
    • Block the unused tubes you don't use. Yes it is common sense, yes we all know why, and yes I did it as I was eager to launch and treated it as a normal rocket. Side note, stout baffles make great lawn dart buffers. Upper BT was totaled, MMT section was very good (slightly smashed where BTs meet).
     
  11. Mar 30, 2020 at 1:47 PM #11

    GaryT

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    If you wanted to fly all 7 motors make a thrust plate with the same OD as the body tube, use L brackets that connect to the trust plate and continue up the side of the rocket between the fins. There's plenty of different ways to screw/bolt to the side, might not be the prettiest but it'll definitely be strong enough and work.
     

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