Revisiting the Estes Maxi Brute V-2...

Discussion in 'Mid Power Rocketry (MPR)' started by James Duffy, Apr 21, 2017.

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  1. Aug 13, 2017 #121

    Glasspack

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    I have a kit like that. The "E" powered 3.94" Dia; 33.5" Tall kit # 1952.

    Been thinking of putting up on the Sale board here on the Forum.......... 20170810_121425.jpg


    I wonder if there would be anyone else interested in building one of these old kits
    I am SURE it would be less than it lists at AMAZON right now ........ HOLY Crap that has to be an error......


    Amazon AD: https://www.amazon.com/gp/product/B01N5H8FVP/?tag=skimlinks_replacement-20

    $1,799.00 + $8.99 shipping
    Only 1 left in stock - order soon. Sold by Vintage Lock
    Add to Cart

    [HR][/HR] [HR][/HR]
     
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  2. Aug 13, 2017 #122

    Woody's Workshop

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  3. Aug 13, 2017 #123

    Steve Shannon

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  4. Aug 13, 2017 #124

    Trident

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    About 5 years ago I had a nice Orbital Transport with custom green decals develop a brownish haze over most of the rocket. What caused it? Testors Dullcote. I switched to Krylon UV-resistant Acrylic Clears. No issues in those past five years. I've used it over every imaginable enamel and lacquer with no issues, and no yellowing. If you buy it at Hobby Lobby, you can also use the 40% discount coupon on your smartphone, or print one from their website. At our HLs, it can be found in the Art Dept., and not with the spray paints.

    I use Matte mostly on anything military or scale, Gloss otherwise. It's also an excellent protective coating for old decals prior to cutting up and dipping in water. If I paint with flats, I Gloss coat the model, decal it, then Matte coat it to restore the flat finish.
     
  5. Aug 14, 2017 #125

    Nytrunner

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    "
    I've used the krylon acrylic clear, but its left my L1 rocket very slightly "sticky". Occasionally it has a sticky sound when leaned against the wall, and once pillow was placed against it (grr.....) and it left these fuzzies all over the nose cone.
     
  6. Oct 22, 2017 #126

    Ez2cDave

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    "Custom" Aerotech motor ???
     
  7. Jan 19, 2018 #127

    aerostadt

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    I just saw in the latest issue of Sport Rocketry that Mr. Duffy's model took 3rd place in the S7 Scale in the U.S. International Flyoffs.
     
  8. Sep 10, 2018 #128

    James Duffy

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    Just as an FYI, a couple more of these Estes Maxi Brute V-2 kits have hit the workbench. If you'd like to see any of the tips or tricks from my previous V-2 build threads amplified or clarified, feel free to ask here...

    James

    IMG_1379.jpg
     
  9. Sep 21, 2018 #129

    James Duffy

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    When this thread started a couple of years ago I noted that I would do things differently if it were ever to become a "serious" (whatever that means) scale project. I've decided to go down that dark path, and build another Bumper WAC that can be used for both the US FAI Team selection event that will take place at NARAM next summer, and might also be flown at the European Spacemodeling Championships to be held in Romania a few weeks later.

    The Estes Maxi Brute kit is a good starting point, but lacks most of the intriguing surface detail found on a real V-2. We'll be trying to add as much as possible, and a good starting point is the field of rivets found just aft of the missile warhead. That area can be seen in this photo of the V-2 on display at the Imperial War Museum in London.

    L1000132.jpg

    The first task is to create a rivet map in Illustrator. There are 32 repeated rivet patterns on each side of the airframe, stacked on two levels. The pattern seems to vary slightly on each preserved V-2, so the rivet map follows the most consistently used pattern. A shroud calculator was used to determine the shroud parameters for the map, and a PDF is attached below.

    More in a bit,
    James
     

    Attached Files:

  10. Sep 21, 2018 #130

    James Duffy

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    The next step is to print out the rivet map, cut out the shroud, and wrap it around the kit nose cone.

    IMG_3518.JPG

    The top edge of the shroud is aligned with the lower scored circumferential line found on the nose cone, and everything is taped into place. The joint on the shroud is aligned with the seam line on the nose cone. That will become critical in a future step, as we'll be covering the nose cone seam with some additional detail.

    IMG_3520.JPG

    A small awl is then used to punch through the pattern, marking the rivet locations on the surface of the plastic nose cone below. There are 38 rivet locations in each rivet group, and two levels of 32 circumferential rivet groups. That means we'll be marking 2,432 rivet locations.

    IMG_3519.JPG

    More later,
    James
     
  11. Sep 21, 2018 #131

    James Duffy

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    With all 2400+ rivet locations marked, we can now remove the shroud pattern. It's tough to make out the rivet locations on this photo, but they are there, and for most projects this would be more than adequate. (Click for full-size image)

    IMG_3523.JPG

    We're going to take this a step beyond, though, and lightly drill out each of the rivet locations with a #64 drill bit held in a pin vise. Each section of 38 rivets takes about six minutes to complete, so this step may take a few days.

    More later,
    James
     
  12. Sep 22, 2018 #132

    zog139

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    Ahh... King of the S7 rivets is making another appearance...
     
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  13. Sep 22, 2018 #133

    TheAviator

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    Hoo boy, here we go. Really looking forward to your build.

    (And I thought you said you'd never touch another Bumper :p)
     
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  14. Sep 22, 2018 #134

    James Duffy

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    The rivet locations are drilled with the #64 bit only deep enough to mark the surface. A few turns of the pin vise are plenty.

    IMG_3531.JPG

    A quarter of the rivets have been drilled so far, or just over 600 locations. The darker rivet locations are the result of a test to improve visibility of the marks with some pencil lead.

    IMG_3532.JPG

    I should also mention that magnification was an absolute must for this little task, and that my cheapo optivisor has become an indispensable tool.

    James
     
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  15. Sep 24, 2018 #135

    James Duffy

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    The last of the 2,400+ rivets have been drilled, and the surface sanded smooth. A rough estimate puts the time needed to complete this task at roughly 6.5 hours, spread over four days.

    IMG_3536.JPG

    Progress was impeded slightly by the fact that our dog has learned how to climb from the back of the hobby room couch onto my workbench.

    IMG_3534.JPG

    Next up is to research, draw, and etch the detail on the forward end of the cone. The arrangement of access doors on the Bumper WAC differed a bit from the standard research V-2 rounds flown at White Sands, so this may take a few days.

    James
     
  16. Sep 29, 2018 #136

    Andrew_ASC

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    That is the most rivets I’ve ever seen added on a rocket. Good luck with your entries.
     
  17. Sep 29, 2018 #137

    Steve Shannon

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    Wow! Looks like Braille!
     
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  18. Jan 24, 2019 #138

    James Duffy

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    Or months, even...

    Still haven't gotten around to the doors, but I did knock out the airframe tube for the V-2 today. Having declared a personal jihad against paper tubes in all their many forms, a replacement was fashioned from a rolled sheet of .015" G10 glass. This isn't a new technique; I freely admit I stole the technique from Mike Nowak and Chris Flanigan, who have successfully used this trick on their large Saturn models.

    First, a piece of .015" thick G10 sheet was sourced from ACP Composites: https://store.acpsales.com/products/2342/fiberglass-sheets-natural

    Next, a section of this sheet measuring 214mm (the height of the tube section) x 316mm (the diameter of the tube X pi) is marked and cut. The maker space through which I had access to a laser cutter went belly-up, so I had to cut this out like a common cave-dwelling savage. A 8mm-wide strip was also cut out to help back up the tube seam.

    I carefully planned out how all of this was going to be clamped up once the epoxy was applied, and did a dry run. Waxed paper was taped into place to keep everything clean.

    IMG_3816.JPG

    Once the clamp sequence was figured out the seam of the rolled tube section was butted together, epoxy brushed into place, and the backing strip positioned. A long caul was placed over the backing strip and the clamps where put into place. Five-minute epoxy was used.

    After allowing the tube to cure for a couple of hours the clamps were removed and a bit of epoxy spoob was cleaned up from the ends of the seam. With that task out of the way the tube was test-fit with the tail and nose cones. A little bit of tape was needed to refine the fit on the tail cone, but this will work just fine.

    IMG_3820.JPG

    So far I'm very pleased with the results. The seam line will eventually be hidden under a scale representation of the longitudinal airframe join strip found on actual V-2 hardware. This was quick, easy, and will certainly yield better results in less time than it would take to do the primer/sand/repeat dance that a paper tube would require.

    More later,
    James
     
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  19. Jan 25, 2019 #139

    Andrew_ASC

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    This is the coolest MPR threads for sure. Not the quickest build, but the coolest.
     
  20. Jan 25, 2019 #140

    Ez2cDave

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  21. Jan 25, 2019 #141

    Scott_650

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    James - does the backing strip end up expoxied to the inside of the tube? Or do you separate it with something? Making tubes from thin G10 is intriguing...
     
  22. Jan 25, 2019 #142

    James Duffy

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    Yes, the backing strip is epoxied directly to the inside surface of the tube. Here's a shot of what the interior surface looks like with the strip in place. (You can see that I used far, far more epoxy than was necessary!)

    IMG_3821.JPG

    This is the first time I have done a rolled G10 glass tube, although I have laid up plenty of glass tubes with cloth and epoxy. The rolled tube technique was far easier than a tube laid up over a mandrel, although it is better suited to larger diameters. I can't imagine making a rolled G10 tube in a diameter smaller than 3" due to the difficulty of getting one's fingers, a caul, and clamps inside the tube to accurately position the join strip.

    James
     
  23. Jan 27, 2019 #143

    James Duffy

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    Another quick update...

    In addition to the main airframe tube that is constructed from rolled G10 fiberglass sheet, there will be two other significant glass tubes on this upgraded Bumper model. One will be the motor mount tube, and the airframe tube for the WAC sustainer will also be glass. Unlike the main airframe tube, these will be created from glass cloth and epoxy laid up over mandrels.

    Here are two tubes are still on their 18mm and 24mm mandrels. Both are made from four wraps of .5 oz. glass cloth and West 105/206 epoxy. The yellow color comes from a single wrap of Japanese tissue that goes on the tube before the glass. The aluminum mandrels are cheap thick-wall aluminum tube sourced from China on eBay, and run about $10 each, shipped. Several heavy coats of Aervoe 3470 mold release are sprayed on the mandrels and allowed to dry thoroughly before the layup starts.

    Once the epoxy has cured for a few days, the mandrel is placed in a 200º oven for about five minutes to soften the wax mold release, then carefully slid off.

    IMG_3823.JPG

    Here are four tubes currently in process. The two bright yellow tubes (#1 and #3) are the 18mm and 24mm tubes that were just removed from the mandrels. #2 and #4 are earlier tubes that have already been primed and sanded. All four will go though a few more prime/sand cycles, then trimmed to the appropriate lengths. Two of the 24mm tubes will be joined together to create the long stuffer tube that the model requires.

    IMG_3824.JPG

    At least one of the 18mm tubes needs to be damn near perfect, as it will be an external, "cosmetic" element of the finished model. The 24mm tubes will be hidden within the model, so we have a bit more aesthetic leeway there.

    This is simply being passed along as an FYI-style post. If there is any interest, I could do a separate thread highlighting how these tubes are made.

    James
     
    Last edited: Jan 27, 2019
  24. Jan 11, 2020 #144

    James Duffy

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    OK, let's see if we can get this project back on track after a year-long pause and resurrect this long-dormant thread.

    The Bumper WAC model featured throughout this thread flew successfully at the first annual Firefly International Rocket Event last March. Unfortunately, the lower section of the model ended up safely out of reach on a power line. Scratch that, no recovery possible.

    Fortunately, the nose cone section was recovered, and I have three (!!) additional Maxi Brute V-2 kits on the shelf, so the elements for a reconstruction are already on hand. So, let's build a new Bumper WAC for the upcoming second edition of the F.I.R.E. international contest, folding in a few more tricks and techniques.

    The first step is to take the recovered Bumper nose cone and add the rivet pattern, as shown earlier in this thread with another untrimmed V-2 cone. Here's what that looks like after the locate/drill/sand process is completed for the 2,500ish rivets:

    IMG_4379.JPG Bumper cone rivets.jpg


    More later,
    James
     
  25. Jan 11, 2020 #145

    James Duffy

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    The fins have been prepared using the techniques shown at the beginning of this thread, and attached to the aft cone. Tamiya putty has also been applied to refine the fit between the fins and the cone using the technique shown is this post. The stuffer tube unit using the 24mm glass tubes we produced last year is assembled using epoxy, and hatch details are added to the exterior of the aft cone.

    V-2 lower components.jpg

    More later,
    James
     
  26. Jan 11, 2020 #146

    James Duffy

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    The stuffer tube assembly is next epoxied into place atop the fin can.

    V-2 aft cone with stuffer.jpg
    Note that a kevlar shock cord anchor has been added to the stuffer tube assembly, and tucked away inside the motor mount tube for later retrieval.

    More later,
    James
     
  27. Jan 11, 2020 #147

    James Duffy

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    Next, we add the cylindrical airframe section we previously rolled from a sheet of G10 fiberglass. There is an opportunity to hide the tube joint under a longitudinal detail that we will be adding later, but we need to plan ahead. The prototypical V-2 tank section is produced in two halves, and then the joints are covered with a pair of long aluminum strips. These strips are (I think...) 15º out of phase from the fin locations. To make sure that we get the G10 tube joint in the correct location, I whipped up a locator template in Adobe Illustrator. (PDF file attached below.)

    After test-fitting everything several times, the G10 tube is epoxied into place with the joint line in the correct location.

    V-2 lower alignment.jpg
    More later,
    James
     

    Attached Files:

  28. Jan 12, 2020 #148

    James Duffy

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    The next step will be to mark and etch the detail for the access panels at the nose of the V-2. The first line to be marked is the joint between the equipment bay and the warhead of the rocket. The Bumper WAC vehicles obviously lacked a warhead (as did all US-launched V-2 vehicles), bit the joint is still there. Intriguingly, the warhead was needed for stability on the V-2, so US rounds filled the warhead with inert weight.

    Long ago whipped up a little jig from a scrap section of BT-70 fitted with a single BT-50 to BT-70 centering ring to help mark this location. The centering ring centers the tube atop the cone, allowing us to mark
    an accurate circumferential line.

    IMG_4381D.jpg

    IMG_4382D.jpg

    After I'm done with jigs like these I throw them into a box for later use.

    More later,
    James
     
    Last edited: Jan 13, 2020
  29. Jan 13, 2020 #149

    James Duffy

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    With the line for the warhead break defined, we can define each of the four quadrants on the nose cone that feature an access hatch. Each hatch is slightly different, but each resides within a single quadrant, and each quadrant is centered extending upward from a fin. Because the fin slots on the WAC launch adapter are centered between the V-2 fins, the slots are a convenient starting point for the lines that we will use to define the hatch quadrants.
    IMG_4383D.jpg
    A flexible ruler is used to follow the curve of the cone and guide the pencil. I didn't capture a photo of it, but the ruler was taped in place to keep it from wiggling around.
    IMG_4384D.jpg
    With the four lines drawn we can see the location of each hatch quadrant.

    More later,
    James
     
    Last edited: Jan 13, 2020
  30. Jan 13, 2020 #150

    James Duffy

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    After plowing through hundreds of photos that I have snapped of V-2s over the years, and consulting a wide range of drawings (none of which seem to agree with each other), here's my take on the hatches that occupy the area just aft of the warhead on the missile. Can I commit that this is 100% accurate? No, but I can tell you that it is a pretty good, well-informed guess.

    V-2 Nose Hatch Details.png

    This drawing is attached below as a PDF file. Next step is to transfer these details from this drawing to the model.

    More later,
    James
     

    Attached Files:

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