Delta IV Heavy

Discussion in 'Internet Finds' started by dhanners, Feb 27, 2005.

  1. dhanners

    dhanners Member

    I was wanting a quick weekend project, and I've been wanting to add a Delta IV Heavy launch vehicle to my collection, so this is the result.

    This model is a departure, of sorts, from my usual stuff. I prefer to work in 1/96th scale, but this is in 1/144th scale. I chose the smaller scale because A) a 1/96th-scale Delta IV Heavy would not be a quick weekend project, and B) Erik te Groen is coming out with a card 1/96th-scale Delta IV Heavy later this year, and if it is anything like the other models he offers, it'll be great.

    The model features my normal skin-on-tube construction. (Sounds vaguely pornographic....) I design and cut the rockets "skins" to shape, then find model rocket tubes that are the appropriate diameter and that's about it. From a building standpoint, the challenges were the thrust structure for the engines and the nosecones. The nosecones aren't the "perfect" shape, but I just couldn't figure out how to incorporate the appropriate "bulge" in them in paper.

    One of the prominent visual features of the real Delta IV Heavy is the ridged and weathered insulation on the fuel and oxidizer tanks. The insulation is sprayed on somewhat like the shuttle's External Tank, but on the Delta IV Heavy, it has a dual purpose -- fire retardant. The rocket is actually designed to catch fire when it launches. If you've seen photos of December's first launch of a Delta IV Heavy, you've probably seen the heavy charring. On the model, the tanks were covered with a ridged paper that I found at an art supply store. I airbrushed it brown, then sanded the paper, giving it the proper weathered look.
  2. dhanners

    dhanners Member

    I posted this on another (plastic) modeling website when somebody asked me how I built the Delta IV Heavy. I thought it might be informative here. Then again, you folks already know a lot of this stuff....

    As promised, here's the "recipe" for my 1/144th-scale Delta IV Heavy. Get out your rulers, T-squares and X-acto knives....

    The rocket is built around three tubes -- the core Common Core Booster and the two strap-on CBCs. I used 1 1/4-inch diameter (or 3.4 cm) cardboard model rocket tube. You'll need 89.6 cm of tubing in all, and since most lengths of the tubing I've found in the hobby shop don't come that long, you'll have to get two.

    The tube for the core CBC is 41.2 cm long, while the tubes for the two strap-ons are each 24.3 cm long. There will also be conical thrust structures, nosecones and payload fairings, but we'll get to those in a moment.

    I cover the tubes with "skins" that I make out of paper or cardstock. I usually use 65-lb. cardstock or lighter, but a weight heavier than regular typing paper.

    There are five skins common to all three CBCs. Each will be 10.6 cm wide. (It's not a bad idea to cut it to 10.7 cm width, then trim as necessary to fit the tube.) From the bottom up, here are the skins and their length:

    * Engine section -- 2.5 cm long. White cardstock.
    * LH2 tank -- 13.8 cm long. I used a paper with soft ridges that I found at an art supply store.
    * Centerbody -- 3.3 cm long. White cardstock. (If you can find corrugated paper at an art supply store, stick a piece 2.3 cm long in the center of this piece.)
    * LO2 tank -- 3.7 cm long. Same paper as the LH2 tank.
    * Top band (an instrument unit, perhaps?) -- 1 cm long. White cardstock.

    A note here on the tank skins. I mentioned that I used a ridged paper that I found at an art supply store. I don't know how to describe it except its ridges are soft and rounded. The sheet I got (and they come in big sheets, but they're inexpensive) was a khaki color. I airbrushed the tank skins with Badger ModelFlex "Shipyard Rust," (and the paint job doesn't have to be perfect or uniform) then when dry, I sanded the skins to rub the paint off the raised portions, giving the tanks the weathered look you see in photos. You can do this sanding before you apply the skins to the tube, or afterwards. If you do it afterwards, though, be careful to not get the sanding dust on the white sections of the rocket.

    The core CBC has additional skins, and again, they are each 10.6 cm wide. Again, from the top band upwards:
    * Interstage -- 5.7 cm long. White cardstock.
    * 2nd stage LH2 tank -- 1.8 cm long. White cardstock, with narrow bands of corrugated paper at the top and bottom.
    * Payload fairing -- 9.4 cm long. White cardstock.

    It's a good idea to use a sharp blade and a T-square to cut the skins, since you want all the angles a perfect 90-degrees; if they're not, they'll come out crooked on the rocket. Once all the skins are cut, you can affix them to the tubes with glue or tape. I usually use double-sided tape since it allows me to pick the skin back up and re-position it if I get it on wrong.

    To do this, I start by laying a piece of angled brass on the tubes and using it as a straight-edge to draw a pencil line down the length of the tube. This will be the line that I use to line up the edges of the skins. On th is model, I applied the Engine Section skins so the edges were on the "side" of the CBC (for purposes of this discussion, we'll call the side of the CBC that has the plumbing and utility tunnel the "front") and then I generally lined up the skins above that on the line I drew, since you can cover the seam with the utility tunnel. Working from bottom to top, I apply the skins one by one, making sure there are no gaps between each skin.

    Now it is time for the conical sections of the rocket -- the Engine Section, the RS-68 nozzles, the nozzles' flexible insulation cover, and the nosecones. There will be three of each.

    The Engine Section is a truncated cone, and I made them out of white cardstock, cut to the following dimensions:

    Small radius -- 2.1 cm
    Large radius -- 3.9 cm
    Angle -- 153.3 degrees

    Once cut, you roll the piece into a cone. I assemble mine with butt joints, but if you don't want to do that, add a degree or two to the angle and use the extra degree as the gluing surface. I then cut disks out of heavy cardstock to glue to the top and bottom of the cone (3.4 cm diameter for the top, 1.8 cm diameter for the bottom) and this will help the cone keep its shape and provided rigidity for the surgery to follow.

    The Engine Section is actually a truncated cone with one side (the "back" side of the CBC) squashed in with a rectangular-shaped fairing running from top to bottom. It's hard to describe it in print, so check photos online, at, for example. Or at or

    I made mine by trial and error, cutting and gluing until I got something that looked decent. Also, on the "front" side of the cone, there are two half-oval shaped indentations. I cut those out and glued in a piece of paper that I rounded to give the proper shape. The paper was cut roughly to shape, and when the glue dried, I sanded the edges.

    A word here about glues.... I usually use PVA glue on my models. It's basically a purer form of Elmer's Glue, is neutral pH and doesn't wrinkle. Elmer's is perfectly suitable, though, and in fact, on applications where I'm going to sand the paper when the glue is dry to get a more rounded shape, I use Elmer's because it sands better than PVA glue.

    The nozzles for the RS-68 engines are next. For mine, I used a silver paper that I found at the art supply store. They were cut to the following dimensions, then rolled into a cone:

    Small radius -- 1.4 cm
    Large radius -- 3.5 cm
    Angle -- 87.3 degrees

    (And speaking of cutting, to make things easier -- and the pieces uniform -- I drew the templates on one piece of paper, then held it and two other pieces together and cut along the lines, making three copies as I cut.)

    There is a flexible heat shield surrounding the base of the nozzle. It is another truncated cone, and here are the dimensions for it:

    Small radius -- 3.8 cm
    Large radius -- 4.3 cm
    Angle -- 70.6 degrees

    Now for the nosecones for the strap-on CBCs and core CBC's upper payload fairing. They're all the same shape, and basically being lazy and figuring there was no need to re-invent the wheel, I borrowed the nosecones from Erik te Groen's excellent Delta III model, which can be found at These are done in white cardstock, and the parts you're looking for are NC2, NC3 and NC4, found on page 5. They need to be reduced in size, though, and if you photocopy the page at 80 percent, it'll be the right size. (And yes, they aren't a perfect match for the Delta IV's nosecones, but with careful construction and sanding, they can come about as close as you'll get working in paper. Paper does have it's limitations, after all....)

    After the nosecones were assembled, a glued a 3.4 cm-diameter disk (again, cut out of heavy cardstock) to the bottom. This provides rigidity for the sanding that will follow. I spread glue along the seams of the pieces of the nosecone, and when dry, sand it with a light-grit sand paper to make the seams more gentle and rounded.

    Once you get the nosecones done and glued to the tubes, your basic rocket is finished. Now it's time for the details, such as the plumbing, utility tunnel, vents, access panels and other bits and pieces. I made the LO2 feedline by rolling the same paper I used for the LH2 and LO2 tanks around a small plastic rod. The utility tunnel that goes right next to it (which is what I used to cover the skin seams on the CBCs) can be made out of laminated several pieces of white poster board and cutting it to size. Or you can form paper around a small piece of wood to get the right shape.

    The rest of the nernie detail was added using various references I've come up with (all from the Internet) and by employing some "creative gizmology," as Shep Paine would say.

    That's all I can think of for now....

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