ESTES PSII Super Big Bertha - Build Thread

Discussion in 'Mid Power Rocketry (MPR)' started by Pull_and_Twist, Mar 18, 2018.

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  1. Mar 27, 2018 #31

    Pull_and_Twist

    Pull_and_Twist

    Pull_and_Twist

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    Day 8:

    Got my centering rings in. Now I can start working again.

    IMG_1187.jpg

    So I started by gluing the forward and middle ring onto the motor tube (middle ring is stock paper one) using ProBond. I don't glue on the aft ring so that I can access the fin tabs after installation.

    IMG_1188.jpg

    Then I gave the rings epoxy fillets for more strength.

    IMG_1189.jpg

    Then I realized I needed to stop and think about how I want to install my rail buttons so that I don't have to keep them on while painting.
     
  2. Mar 30, 2018 #32

    Pull_and_Twist

    Pull_and_Twist

    Pull_and_Twist

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    Day 9:

    Today I decided to glue in the motor mount and attach the fins.

    Started by attaching some eyelets to the aft centering ring. That way I can use it to center the motor mount while I glue the forward and center ring... but still maintain the ability to pull it out after the fins are attached so I can add epoxy fillets on the inside.

    IMG_1207.jpg

    Then I decided where I wanted to put my rail buttons and launch lugs. Marked the locations on the tube.

    IMG_1208.jpg

    I shoved in the motor mount and used the fins to help me position it.

    IMG_1209.jpg

    After, I glued the first ring into position with 5-min epoxy.

    IMG_1211.jpg

    I then headed over to payloadbay.com and printed myself out a fin guide and glued it to some foam core board. Cut out the inner portion so I can use it as a jig for when I glue the fins on.

    IMG_1215.jpg

    I finally attached the fins using some ProBond and slipped the fin guide onto the tube and fins.

    IMG_1216.jpg

    Now I will let it sit like that for 24 hours.
     
  3. Mar 30, 2018 #33

    Pull_and_Twist

    Pull_and_Twist

    Pull_and_Twist

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    Day 10:

    Continued working on the fin can...

    Pulled out the aft centering ring so I can epoxy the fins to the motor mount.

    IMG_1218.jpg

    Added 5-min epoxy fillets to the fin tabs where they met the motor tube as well as next to the body wall. Then I covered the middle centering ring in 30-min epoxy and let that all set.

    IMG_1221.jpg

    I then replaced the aft centering ring and added the rear rail button nut. I made sure to keep the threads epoxy free so I can screw in my rail buttons after paint.

    IMG_1227.jpg

    Did the same for the forward one.

    IMG_1229.jpg

    Turned out pretty good for my first time using rail buttons.

    IMG_1231.jpg

    I then laid down a layer of 30-min epoxy over the aft centering ring.

    IMG_1233.jpg

    After that cured, I started to mark my fillet lines. I used a piece of 1/4" dowel covered in pencil to do that. I will also be using a 1/4" dowel to shape it.

    IMG_1234.jpg

    I then masked the rocket where the lines were drawn.

    IMG_1235.jpg

    Finally I put 30-min epoxy into the edge and ran the forming dowel down the fin. After 10 mins I pulled off the masking tape.

    IMG_1236.jpg

    I let the epoxy set for an hour before moving onto the next side. I managed to finish two sides today.
     
  4. Mar 30, 2018 #34

    Deke

    Deke

    Deke

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    Pull_and_Twist - I have the same rocket and I like the idea of the centering rings you upgraded to but I'm not quote sure which ones to get. Looks like part # CR6080-W from Balsa Machining Service?
     
  5. Mar 30, 2018 #35

    Pull_and_Twist

    Pull_and_Twist

    Pull_and_Twist

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    CR52H80-W is what I used.
     
  6. Mar 30, 2018 #36

    Deke

    Deke

    Deke

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    THANK YOU!!!

    Outstanding build by the way!
     
  7. Mar 31, 2018 #37

    FlyBy01

    FlyBy01

    FlyBy01

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  8. Apr 3, 2018 #38

    Pull_and_Twist

    Pull_and_Twist

    Pull_and_Twist

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    Day 11:

    Finished the other two sides of epoxy fillets and decided it was time to push foreword to the paint stage.

    But first I had to apply the launch lugs using 5-min epoxy.

    IMG_1257.jpg

    Then I coated the inside aft end of the motor tube with super glue to make the cardboard stronger. I also utilized some 5-min epoxy to attach the motor mount.

    IMG_1258.jpg

    I then applied fillets to the lugs using the same technique as used on the fins.

    IMG_1274.jpg

    Following that I decided to glue the bottom fin can to the coupler with epoxy and attached the bottom portion of the shock cord: 750 lb Kevlar cord.

    IMG_1287.jpg

    I then glued on the top tube with epoxy and got rid of the seam with wood filler. Also coated the top inside of the tube with super glue so it can better handle the nose cone being repeatedly pushed in and out of it.

    IMG_1290.jpg

    Finally everything is assembled; next is priming and paint.
     
  9. Apr 12, 2018 #39

    Pull_and_Twist

    Pull_and_Twist

    Pull_and_Twist

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    Day 12 - 16:

    Finally was able to start painting. I covered it in two coats of white primer and sanded it like crazy.

    Then I gave it two strong coats of gloss white.

    IMG_1354.jpg

    Followed by the red fin can.

    IMG_1358.jpg

    Finally I was able to put it all together and get the decals on. Turned out pretty good. Still needs a solid coat of clear.

    IMG_1359.jpg IMG_1360.jpg

    Can't wait to launch it.
     
  10. Apr 12, 2018 #40

    qquake2k

    qquake2k

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    Looks really nice!
     
  11. Apr 12, 2018 #41

    Jozef

    Jozef

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    Very nice build and finish. Do you have a weight without motor?
     
  12. Apr 12, 2018 #42

    Pull_and_Twist

    Pull_and_Twist

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    Thank you.

    Thanks. The weight comes in at 73.26 oz / 376 g with everything but motor and chute release installed.
     
  13. Apr 12, 2018 #43

    liv3mind

    liv3mind

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  14. Apr 12, 2018 #44

    BEC

    BEC

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    Uh....which is it? 376g is 13.26 ounces, not 73.26. 73.26 ounces is 2077g, which puts it firmly over the limit for an FAA Class 1 rocket and therefore it needs to be flown only under a high power waiver. Since the kit parts weigh on the order of 360g (I just weighed one but I didn't take the fins or the small parts out of the bags) I have to think it's the latter - 2.08 kg. No flying of that one at Sixty Acres.....not that that's happening this weekend anyway. This one will need to fly over with Rich at Tri Cities or at FITS or something.

    That said, it IS gorgeous.
     
  15. Apr 12, 2018 #45

    bibbster

    bibbster

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    I'd say his '7' is a typo since if it were a '1' it would match the gram conversion, 13.26oz.
     
  16. Apr 12, 2018 #46

    BEC

    BEC

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    Yeah, I noticed that. It can't be that light though - an unbuilt and unmodified kit weighs more than that. With all his mods, it's going to be rather heavier.
     
  17. Apr 12, 2018 #47

    bibbster

    bibbster

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    Oh yeah. Duh. Monday round four. :lol:
     
  18. Apr 12, 2018 #48

    Pull_and_Twist

    Pull_and_Twist

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    The 7 was a typo... it’s 13.26 oz according to the shipping scale I used. I’ll make sure it’s calibrated correctly and weigh it again when I get home from work.
     
  19. Apr 12, 2018 #49

    Pull_and_Twist

    Pull_and_Twist

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    Its definitely not 2077 g... my Argent is about 2.5 lbs loaded and this one feels slightly heavier then my Star Orbiter and nowhere near as heavy as the Argent.
     
  20. Apr 12, 2018 #50

    BEC

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    It will be interesting to see what it really is. Even with the mods there's no way you doubled the weight.

    I'll go back and re-weigh the kit I did earlier. Admittedly it has plastic bags and the full fin sheets in the weight I listed above. I don't remember what my first SBB weighed, and the wreckage is gone (it hung in a tree for over a month in the winter, then got bashed around on the ground before it was recovered - or so it appeared).

    A nearly stock Star Orbiter is less than 6 ounces though....
     
  21. Apr 12, 2018 #51

    Pull_and_Twist

    Pull_and_Twist

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    Ok... I calibrated the scale and it's outputting valid values... final results are:

    Super Big Bertha 13.30oz / 377g / 0.831lb

    and in comparison;

    Star Orbiter 7.16oz / 203g / 0.448lb

    My Star Orbiter isn't built stock either... pretty much has the same mods as the Bertha but with no baffle.
     
  22. Apr 13, 2018 #52

    BEC

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    Cool. Thanks for the info.

    The Star Orbiter I checked has a simple baffle and the upper six inches made into a payload compartment with a stage coupler, a ply disc and a screw eye (see the Star Orbiter thread for a bit more). But it doesn’t have any beef-ups. It came in at 5.77 ounces.

    I gotta get on the build of my next SBB....
     
  23. Apr 13, 2018 #53

    Jozef

    Jozef

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    What primer and color paint system did you use?
     
  24. Apr 13, 2018 #54

    Pull_and_Twist

    Pull_and_Twist

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    On this one I used Rustoleum painters touch for primer, then gloss white and gloss apple red. I always get crinkling with their clear though so I plan to use a high gloss acrylic for that. Tend to stick with one brand and line for the entire process if I can to avoid adverse reactions.
     
  25. Apr 13, 2018 #55

    Jozef

    Jozef

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    Thanks, Very nice work.
     
  26. Apr 22, 2018 #56

    Pull_and_Twist

    Pull_and_Twist

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    Day 17:

    Finally got some good weather and managed to clear coat her.

    Finally attached everything together too. Used elastic shock cord connected to the kevlar bottom and a quick link up at the nosecone. Replaced the shoot with a nylon one and have that hooked to a swivel and then the quick link as well.

    IMG_1445.jpg

    These are the swivels I use... they're made for fishing and come in strengths ranging from 20lb to 1000lb. I used a 380lb one for this build.

    IMG_1439.jpg

    I then attach kevlar loops to the ends so that I can run my parachute and quick link through it (used 500lb kevlar here.) The knots are epoxied.

    IMG_1440.jpg

    In a week I'll be able to finally launch it.
    Can't wait.
     
  27. May 7, 2018 #57

    Pull_and_Twist

    Pull_and_Twist

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    Launch Day:

    Finally got to let this thing fly... and it did fantastic.

    IMG_E1559.jpg

    Made it to 645ft on a Estes F15-6.

    IMG_E1561.jpg

    Enjoy the video!



    Put it up a second time and it performed just as well.

    Might try some composite motors on it next time.
     
  28. May 7, 2018 #58

    BEC

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    It sure puts up the prettiest flights, doesn't it?

    The improvements did cost you some altitude....the two F15 flights for which I have data went to 820 and 929 feet (but no Chute release, and the altimeter was the smaller, lighter FireFly).

    I shot the second color on my replacement SBB today. It again was built essentially stock (except for adding a baffle). It weighed just under 9 ounces before paint. I'll have a final weight in a day or two.
     
  29. May 7, 2018 #59

    RocketFeller

    RocketFeller

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    We flew my son's Super Big Bertha last Thursday at the weekly rocket club meeting at our school. We used an adapter and flew it on a D12-3. It was a perfect flight to around 200-300' (just a guess, no altimeter on board) with deployment just as it arced over.

    Ours was 12.6 ounces ready to fly, the only deviation from stock build was a nylon parachute.
     
  30. May 9, 2018 #60

    BSNW

    BSNW

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    That is a beautiful ride! I bet it would also be glorious on an F40-W for a nice long slow boost OR even a G64W! No problem with your chute release. I think the H128 would be too fast....more like artillery. I say try the F40!
    Andrew
     

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