2.6" ASP WAC Corporal Build

Discussion in 'Mid Power Rocketry (MPR)' started by Theory, Feb 4, 2019.

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  1. Feb 4, 2019 #1

    Theory

    Theory

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    SSSSSSSSOOOOOOOOOOOOOO my 2.6" ASP WAC Corporal kit has arrived and assembly will begin shortly. I haven't seen a build thread for this kit so I figured I would try my hand at one. I am planning a few minor deviations from the directions, but nothing crazy. I am going to replace the 1/4" lugs with rail buttons, likely going to replace the elastic with tubular nylon and will also add a Kevlar chute' protector. I am also not 100% sure about the cable shock cord mount; that may be replaced with a longer Kevlar solution. Finally I plan to permanently mount the 29mm adapter to the MMT and add an Aeropack retainer. The kit will be well under 30oz when complete and flight ready. With the number of 29mm motors on the market I will have plenty of options for VERY respectable flights. Also, the idea of using an adapter for 99% of my flights isn't my style. This is also why I'm posting this in the 'mid-power' sections as the vast majority of her flights will fall in the G to "baby H" range.

    This build will be taking place along side a few others (note the High Flyer XL) in the background (it will be strengthened to take advantage of the Aerotech 24/60 case) and I also have an Aerotech Arreaux on the way. But I digress...

    Adhesives will be hobby epoxy, so nothing crazy there, and finishing will be rattle can primer and satin white & black.

    Stay tuned as I anticipate good things!!!
     
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  2. Feb 4, 2019 #2

    Theory

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    0EBBB74F-CE2C-4B73-ACD5-5CBBA354B71E.jpeg The obligatory parts picture
     
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  3. Feb 4, 2019 #3

    lawndartman

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    Many flights on mine... great for a quick shot... I will be watching for your build thread. BTW this kit is perfect for a JLCR!
     
  4. Feb 5, 2019 #4

    Theory

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    Yes, a JLCR is on my list of “rocket stuff to buy”
     
  5. Feb 5, 2019 #5

    Mugs914

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    Excited to see your build. I have wanted one of those for a while now, but this is the first time I've actually seen one. Even nicer looking than I expected!
     
  6. Feb 5, 2019 #6

    NAR29996

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    I have several flights on mine without any upgrades to the recovery system.
     
  7. Feb 6, 2019 #7

    Theory

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    Made a little progress this evening.

    Sealed the tube edges with CA and test fit the tail cone, motor tube and fin. All looks good there. So far I am VERY happy with the quality of the kit.

    I also began working the anchor location for the aft rail button in the tail cone. Drilled a hole and inserted a pice of dowel then soaked it all in CA. Love the way this turned out.

    Finally I used some 30min to adhere the tail cone and aft most centering ring to the motor mount.
     
  8. Feb 6, 2019 #8

    Theory

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  9. Feb 6, 2019 #9

    Theory

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    recovery system modification idea:

    replace the short (and thin) steel cable with 20" of 750 pound tubular Kevlar. This would be wrapped, tied and epoxied around the MMT below the forward centering ring, and passed through a slot cut (really this slot would be made with a semi-circular file to make the transition very smooth) between the forward centering ring and the MMT. The other end would be tied into a loop and secured to 15' of 5/8" nylon strap. I would also use this "junction" to tie in a 9X9 reusable chute protector.

    thinking that this should be plenty strong and also fairly flame proof.

    thoughts?
     
  10. Feb 6, 2019 #10

    dr wogz

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    Motor retention?

    I do that with a lot of my builds: Kevlar shock cord tied around the MMT. If you can, add a bit of shrink tube over the lower portion, for a little added shielding. Make sure you work the epoxy into the Kevlar weave.. I like to have my loop at the top end extend pas the BT by a few inches. I then tie in a bowline knot, and a half hitch on the tag end to be secure. Kevlar tends to unravel / untie fairly easy! And a piece of tape over that!
     
  11. Feb 6, 2019 #11

    Theory

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    rodger that!

    motor retention to be handled by an Aeropack retainer
     
  12. Feb 6, 2019 #12

    lawndartman

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    I LOVE the dowel idea, thanks for that tip. BTW, I used a GLR retainer. I used a drummel to open the tailcone a tad and mounted it flush.
     
  13. Feb 6, 2019 #13

    Theory

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    thank you, though I must give credit for the idea to Steve Shannon (https://www.rocketryforum.com/threads/conformal-guides-vs-buttons-for-my-wac-corporal.150763/)

    as for the retainer, I am going to be permanently installing the 29mm adapter and using an Aeropack system for retention. the 29mm H and I motors from Aerotech and most of all CTI will be all the motivation this sub 30oz bird will need.
     
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  14. Feb 6, 2019 #14

    lawndartman

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    So true on the motors. Light and fast. This is what makes this kit so nice.... Mine was gone on a CTI-I205 Imax.
     
  15. Feb 7, 2019 #15

    Theory

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    Got a little more done today. Gotta say that I am a sucker for detailed fins, and these really drew me to the kit. The ply core is laminated on each side my a piece of balsa of the same thickness. The final assembly is a tick over 3/8”.

    I went with titebond for the laminating, and why not - wood to wood, no mixing and you can spread it with your finger!

    B1A8756F-C057-4BEE-AC77-55E603CB0401.jpeg

    Once each side was covered in glue and placed I sandwiched them between some pieces of granite covered with parchment paper. (Pro tip - nothing sticks to parchment paper!)

    5EE0E1B1-5496-4631-95E0-0BDA2523A181.jpeg


    I also addressed the forward centering rings. They were glued together with titebond and once dry, the edges were doused with thin CA. I then “cut” in a notch for the Kevlar with a file

    7D880E6C-81C7-4D88-AD0C-F5B514413676.jpeg


    Very happy with the progress and the way everything is going together

    Next up, glassing the nose cone, marking the airframe and cutting the slots.
     
  16. Feb 7, 2019 #16

    dr wogz

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    To me, this seems wrong. Adding CA to the edge seals it up, so the next glue you use (epoxy, wood glue..) won't penetrate into the wood when you go to glue the mmt assembly in place.

    But, I am enjoying your build! keep it up!
     
  17. Feb 7, 2019 #17

    Nytrunner

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    This sentence makes be sad, but otherwise nice build!
     
  18. Feb 7, 2019 #18

    Theory

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  19. Feb 7, 2019 #19

    Theory

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    thanks! ...and don't be sad as there is nothing sad about a 29mm 5 or 6 grain CTI motor!!!!!!!!!!!!!!!!!!! a 312H160 Classic would orbit this thing!
     
  20. Feb 10, 2019 #20

    Theory

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    Got a little more done today. Tube marked, slotted and everything test fit. Not a ton of progress, but moving forward. Tomorrow I will likely tackle the nose cone or begin creating a jig to bevel the fins.

    4D3C858C-6DB4-4A34-9402-0CF17BACCAA4.jpeg
     
  21. Feb 10, 2019 #21

    Theory

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    Fins...

    DCE3AF19-A7C7-41CF-9EA7-DD06618D7C95.jpeg B33C1260-2FDB-4DB4-A050-A3CE972C31DD.jpeg AC3CF9FE-C9C3-41BE-9457-95F206F2C437.jpeg F44CB1DB-5AF9-4BA3-BE57-4DAF95B09154.jpeg 72E690C3-B1C9-4E65-A51E-E3000F382B61.jpeg
     
  22. Feb 10, 2019 #22

    Theory

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    Nosecone work. Warm 20 BSI laminating epoxy and the provided light glass cloth.

    AE34E0C6-A270-4A82-A978-F2385D78E0F1.jpeg
     
  23. Feb 10, 2019 #23

    Theory

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    All done. A good deal of sanding in my future, but no worries.


    12B68A7D-9F53-49CD-A4C3-BF8550689D94.jpeg
     
  24. Feb 10, 2019 #24

    aerostadt

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    Nice bevel on the fins! How did you do that?

    (Nice close-up photo shot!)
     
  25. Feb 11, 2019 at 1:21 AM #25

    Theory

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    Aero-

    Made a quick jig with some wood blocks and some 220 grit. Keep them square and you can sand to any degree you want.

    I didn’t take mine to s knife edge as I doubt the actual rocket had a razor for a leading edge

    3F68444C-C7CF-4E2D-98A4-4766A4F727CA.jpeg
     
  26. Feb 11, 2019 at 3:53 AM #26

    jlabrasca

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    Nice build.

    The WAC Corporal actually had airfoiled fins.

    Pictures here

    https://airandspace.si.edu/collection-objects/rocket-liquid-fuel-sounding-wac-corporal

    Peter Alway's drawing (by way of John Coker) here

    http://www.jcrocket.com/images/waccorporal/rotwdrawing.jpg

    The 3-sided bevel was Estes' idea, I think -- as was moving the conduit around to a position where it could hide the launch lugs.

    edit: I remember, but cannot find, a forum thread about a pre-estes WAC Corporal model. MMC? IIRC (and I probably don't) it had the same bevels as the Estes kit. An even more vague recollection that the bevel was something to do with a period photograph of the rocket in which the glint of light from the fins gave the impression of a double-diamond profile.
     
  27. Feb 11, 2019 at 4:32 AM #27

    Mugs914

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    This is one of the pics that suggested that the WAC had bevelled fins. (They actually have a lenticular airfoil, evident in the second pic)
    WAC-Corporal_color.jpg

    wac_corporal_missile_hero_1280x436.jpg It looks like the fins were buffed around the edges resulting in the different tone to the bare aluminum.

    It also shows how crude the WACs were, by modern standards. Just had to be good enough to fly once, I reckon...

    One of my all-time favorite rockets.
     
  28. Feb 11, 2019 at 11:40 AM #28

    Theory

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    One lucky thing about living in the DC area is my proximity to both Air and Space museums. (note the WAC picture in my avatar) In fact when I am working down town (every other month or so) I walk right past it. As of now I am scheduled to be down there next week and plan on stopping in to take several more pictures. I want to take notes on the fins to include the locations of the mounting 'screws' (there look to be 9 per fin), and also make notes on paint.
     
  29. Feb 11, 2019 at 2:59 PM #29

    jlabrasca

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    Yeah - I spotted your avatar picture right after I posted the bloviation on the fin profile <smile>.

    There is also a WAC Corporal at the White Sands museum. Its stripped (or it was never painted) so it doesn't photograph as well as the SI specimen.

    WSWAC1.png [​IMG]

    John Coker has some good reference material collected from his 1:1 build.

    http://jcrocket.com/waccorporal.shtml

    The SI site describes those transparent cones protruding from two of the fins as "flare housings". You can see the same feature eon the White Sands specimen. My desultory and inexpert searching hasn't turned up the full story on those -- but they look cool. It'd be a nice challenge to model those, with lights for a night launch. <smile>

    Yeah, that's what I figured too. According to this entry,

    http://www.astronautix.com/w/wac.html

    the WAC Corporal was designed to be recoverable and reusable.

    (In case you were wondering if it would be period-appropriate to fly yours with field dirt on it)
     
    Last edited: Feb 11, 2019 at 3:07 PM
  30. Feb 12, 2019 at 4:30 PM #30

    Theory

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    Thinking about creating the flare housings on the fins out of a piece of 1/4 dowel. It will take a good deal of sanding, but I bet I could get close. I will likely skip the portion that protrudes past the bottom of the fin as it will be asking to snap off on the first flight

    As for the nose cone, sanding went well. I may lay one more thin layer of epoxy on the hit it with some 320 grit before priming and paint
     

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