My LOC IV Build Thread

Discussion in 'Techniques' started by Curtis Enlow, Apr 15, 2019.

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  1. May 27, 2019 #31

    mbeels

    mbeels

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    I've had that happen with other brands as well. My thought that it wasn't so much the paint getting applied to the top of another layer, but it seemed to happen when the top paint layer had an opportunity to seep under the edge and reacted with the layer below it. But it is inconsistent, and still happens occasionally, I don't know why.
     
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  2. Jun 1, 2019 #32

    Curtis Enlow

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    As the Tri-City Rocketeers SWOOSH! fly-in nears i get closer to completion. With some help from some of the kind folks here (and several frustrating hours slaving over a hot keyboard on Open Rocket) I think I have a selection of motors that will A) maiden the stock LOC IV on a short hop with a 29mm 'G' just to make sure the darned thing flies, and then B) a pop-at-the-top 'H' motor that will, hopefully, earn me my L1 (Yes, those voices that said I should keep it simple for my L1 finally got through my thick and somewhat stubborn skull), and finally C) a beefier, but more workable 'H' that will allow me to fly the HP/DD version of the IV I call the Super IV. The 'I' I was contemplating had too quick of a motor ejection charge. Maybe I'll find a suitable higher impulse motor for later in the season if all goes well on the 'H'.

    Today I tested the RRC3 in sim mode with e-matches only in the sled with fllght batteries (300mAh LiPo) and they fired off just fine.



    I also built some charges for the test deploy tomorrow (if all goes well). I used the floral foam the muzzle loading gun shop proprietor told me about as wadding and it worked really well. It compresses nicely with the butt-end of a hobby knife and was easy to load just by pushing the open end of the vial into the block and tamping it down.

    [​IMG]

    My scale only goes down to a tenth of a gram, so I went .1g lighter on the calculated load for first shot, then have the calculated loads, as well - 0.86g. for the drogue and 0.76g. for the main. I may have to get a more sensitive scale for future use (or if the test proves i need to be more precise).

    [​IMG]

    BUT...this might all be moot.

    My Father's recent illness, a flurry of work including a business trip and a later-than-anticipated delivery from a vendor (that set me back about a week and a half) has kept me on my toes, and I didn't have the time to simulate and order motors from an online vendor. I was given contact information for a vendor that might have the motors I need that might be at Tri-Cities, but if I can't source the proper motors...I'm not flyin'. And that would suck.

    Sent off an email but no response yet. If this vendor doesn't work i can appeal on the local club email chain and see if anything pops up.

    Wish me luck with that and with the deployment test tomorrow.
     
    Last edited: Jun 1, 2019
  3. Jun 2, 2019 #33

    Curtis Enlow

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    The good news is that I did a successful ground deploy test of my main using a shop-vac and an RRC2-Mini.

    The bad news is that the nose cone bulkhead...ummm...departed the aircraft (as the NTSB would say) well before reaching the end of the shock cord, sending the nose cone across the yard like a 16" shell heading for the battleship Bismarck. From the slo-mo on the video, the bulkhead parted ways with the nose cone almost as quickly as it left the forward BT.



    At first I thought the load was too great and my cheapie harbor Freight digital postage scale was WAY off, but after running and getting a more accurate scale (small and has hundredths of a gram: https://www.target.com/p/taylor-digital-food-scale/-/A-53280869) I found the HF scale was surprisingly accurate (though it only has tenths of a gram). I started with a light load - the numbers said I needed 0.76g charge for the main, but this charge was only 0.5 (the HF scale only had tenths, my new one has hundredths).

    Now, the bulkhead was a tight fit, in fact after inserting it past the shoulder I had to grab the U-bolt and give it a pretty good tug to pull it against the shoulder inside the NC, and it was set with 30-min epoxy. I am assuming that the charge 'ballooned' the nose cone, forcing the bulkhead forward like a piston and the resulting pressure blew it out, since it is pretty clear the shock cord had nothing to do with it. To be honest i think I just didn't take the due care & diligence I should have in preparing the inside of the nose cone; I washed but didn't scrub the interior and there was probably still release film there. Also, I noticed there was really no epoxy on the nose cone shoulder at all, so I need to roughen that area significantly with coarse sandpaper. Also, I used a 30 min epoxy, and noticed it was quite brittle - I could snap it off with my finger tips and should should have been hard and sharp. So i will use a better quality, long-setting epoxy and will weigh it instead of measuring it.

    I need to clean up the bulkhead, really roughen up the shoulder and use a longer-setting epoxy with some glass fiber for added strength.

    Generally, though, I was happy with the test (other than the little set-back with the nose cone mod). The RRC2-Mini fired off as it should have. The charge would have, otherwise, been sufficient for the Main deployment, and the AV bay was sealed pretty well, and the high-pressure hose I used to extend the charge cups withstood the blast perfectly.

    The other good news is that I found a rocketeer who lives very close to me and who has a bevy of motors that will work perfectly for both the LOC IV and the Super IV, so I will be able to attend the Tri-Cities SWOOSH! after all. Well, that is if all the other stars in my Universe align, as well.

    More tests tomorrow (and this time Mr. Professional Sound Guy will set the borrowed camcorder mics properly so the video actually has native sound ;)
     
  4. Jun 2, 2019 #34

    Steve Shannon

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    Are you sure you didn’t have the charge inside the nosecone?
     
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  5. Jun 2, 2019 #35

    Banzai88

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    60 grit scuff and rocketpoxy. Never had a nose cone bulkhead give way having done that.
     
  6. Jun 2, 2019 #36

    Curtis Enlow

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    Ya know, Tom, there is another aspect i didn't consider yesterday: You may have noticed in the latter part of the video I have two T-nut provisions for nose cone weight in the bulkhead and those two 1/8" holes were unplugged. So the idea that, somehow, the bulkhead was blown in to the nose cone and then the resulting increase in pressure inside the nose cone blew it back out sounded logical at the time but may not be accurate.

    I think the failure on my part of due diligence in securing the bulkhead properly is key, however, I think the open holes allowed the charge pressure to equalize quickly, however, and combined with the weak adhesion was also the fact that there was no internal pressure inside the nose cone to support, if you will, the bulkhead against the forces of deployment allowing it to become detached, rotate and exit the nose cone easily.

    But, yes, I scuffed the heck out of it, used weighed high-quality, long set epoxy and milled glass fibers, and I plugged the weight adjustment holes. I think that should do it, but in the future, before finishing i am gonig to also install small rods, radially, to help secure nose cone bulkheads.

    Live, screw up, be a warning to others & learn. I should make that my new motto ;)
     
  7. Jun 2, 2019 #37

    Curtis Enlow

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    LOL, I know, right...?
     
  8. Jun 3, 2019 #38

    Curtis Enlow

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    Things went much better with the main & drogue tests today, starting well below calculator recommendations and working my way up. Waiting on a larger sized chute from Spherachutes and picking up a range of motors tomorrow that will get me from a low Mid-power stock LOC IV up to a near 2K HP/DD on the Super IV kit mashup. Now, if the weather at the launch site will just hold up, by golly, I might just get to go :)

     
  9. Jun 3, 2019 #39

    rharshberger

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    If your larger chute doesnt show up by this weekend I have at least one you can borrow that will do the job its a 60", so that offer still stands.
     
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  10. Jun 3, 2019 #40

    Curtis Enlow

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    Thanks, Rich!

    I wrote the folks at Spherachutes and they promised it out on Monday, and that means it usually gets here by Wednesday. I appreciate the back-up, tho!

    C
     
  11. Jun 6, 2019 #41

    Curtis Enlow

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    I found the perfect motor for my L1!

    [​IMG]
     
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  12. Jun 7, 2019 #42

    Curtis Enlow

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    Rocketry will be on the back burner for a week, or two, as my Father passed this morning.

    I will be back.
     
  13. Jun 7, 2019 #43

    Scott Hala

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    I am saddened to hear of your loss. Please pass along my condolences to your family. :(
     
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  14. Jun 7, 2019 #44

    Steve Shannon

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    I’m sorry.
     
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  15. Jun 7, 2019 #45

    Nytrunner

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    I'm terribly sorry to hear that Curtis, may you and your family have peace and comfort in the days ahead.

    (rockets will be there if you need to clear your head in awhile)
     
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  16. Jun 8, 2019 #46

    boatgeek

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    I'm so sorry to hear that. Best wishes to you and your family in a difficult time.
     
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  17. Jun 11, 2019 #47

    Curtis Enlow

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    Thank you, everyone, for your kind words & thoughts,it is comforting and I appreciate it.

    Curtis
     
  18. Jun 17, 2019 #48

    Curtis Enlow

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    My local rocket friend, Nick, invited me out for a Father's Day Launch a Box 'O Rockets day with him and his awesome daughters, so I brought along the standard LOC IV for its maiden - flew perfectly straight up on a G76 and returned safely to Earth and iI was very happy & re-inspired after a difficult week and a half. Thanks, Nick.

    Pardon the phone video and its refusal to focus at the end, but you'll get the idea. Next up, Richland, Wa. for the HP/DD Super IV version!

     
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