1/48 Northrop Grumman RQ-4B Global Hawk

[Downen Scaled Replicas]

Models of UAVs are few and far between. The number of options in 1/48 scale can just about be counted on one hand. As they become more prevalent in both military and civilian service hopefully we’ll see more kits become available.

 

I’m glad to finally get started on the 1/48 Northrop Grumman RQ-4B Global Hawk from Skunk Models Workshop. There were a few pre-production “A” vehicles with shorter wingspans and fuselages, and the Navy has contracted for a “C” version with a strengthened wing. This “B” version is the most widely operated today.

 

 

The kit comes with four sprues covering the fuselage and two very long wings (this is going to be a BIG kit in 1/48 scale).

 

 

 

 

Instructions are contained in a small pamphlet (it’s not a complex build) and the decal sheet includes options for German Luftwaffe and USAF vehicles.

 

 

The Allison Rolls-Royce AE3007H turbofan engine is adequately represented with the fan face visible through the inlet duct and the mixer in the nozzle.

 

 

Construction starts with the cockpit and the ejection seat is… oops… no cockpit on this one! It’s actually a quick build to get something that begins looking like an air vehicle, which is refreshing. The fuselage comes in two halves plus the bottom which will trap the wing halves a bit later.

 

 

You can see here that there will be a gap between the aft fuselage right/left halves and the bottom fuselage. Placing a support tab inside the fuselage in this area will really help with alignment later.

 

 

Access panels for the engine are separate, but unfortunately there is no engine to display! Too bad… this would make a terrific diorama.

 

 

Installing the bottom wing parts into the top wings reveals gaps at the roots and a bit of overhang at the tips. No big deal. I’m also going to display my model in flight, so the landing gear doors will be closed. There’s not much detail inside those gear bays anyway, so plan to do a bit of scratch-building if you want to display the gear down.

 

 

I really do prefer to display aircraft models doing what they were designed to do: fly. One of my approaches is to drill a hole in the bottom of the fuselage to accept a 5/32” diameter brass rod.

 

 

Here you can see a short length of 7/32” diameter plastic tube cemented into the fuselage and fixed in with a blob of Milliput epoxy putty. The wing will sit directly above this area and act as the stop when I insert the brass rod. Also note that I’ve backed the main gear doors with Milliput to make the doors a bit more robust; I’m going to need to sand the outside of the doors to get them to fit smoothly and that process can be rough if they don’t have a good, solid attachment to the wing.

 

 

So far it’s a quick build. The wings in my kit are warped / drooped which I don’t believe is intentional and which won’t look right in flight. I’ve got to think a bit about how to fix that and perhaps give them some upward flex. More later…

[dnl42]

Nice start on this.

 

As you noted, the wings are quite long and will droop due to their weight. But, they should indeed bend up due to air loads. I wonder if this would work: jig the upper wing to the proper bend, bond some carbon fibre on the bottom of the upper wing with epoxy, wait for the epoxy to cure, and finally glue the lower wing onto the upper wing while in the jig.

[skyhawk174]

Nice start on this big kit. I too have it in my stash. I plan to have mine on its gear and I am think ing of how to fix a couple of issues I am sure will creep up.

 

1. Those wings are long and I worry about drooping. I am thinking of adding some sort of spar like a carbon fibre rod. I am also going to try and use some rare earth magnets so that I can remove them for transport.

2. I saw someone had some RAAF decals for this kit but I think that is a what-if. Will look for it.

3. Be careful about the wheels. If you look at the box top is shows two wheels per gear but I don't see it on your instructions. Ther is only supposed to be one per gear. I have the first release and it has me putting on 2 wheels.

 

I will follow this build.

 

[dnl42]

I just measured the wing droop on my model, built about 4-5y ago. The wing leading edge is 30mm at the wing root and 15mm at the tip.

 

My model only has 1 wheel on each MLG, which is apparently correct for an RQ-4B. 2 wheels on each MLG are apparently correct for an RQ-4A.

 

Also, check out those WALK WAY decals. On my kit, the starboard side decals are a mirror image of the port side decals, including backward text! 

[Downen Scaled Replicas]

Droopy McCool...  LOL

 

 

[Downen Scaled Replicas]

Hey dnl42 and skyhawk174, thanks for the alerts on the main gear wheels. I'll do this one gear up, hence the preoccupation with the wing droop. I'll take a look at those wing walk decals... mirror image text, eh? Great!

 

I worked a bit last night on the wing droop. I anchored the wings to a slightly curved surface (curved them up) and hit them (gently) with a heat gun. SOME improvement from that effort. I also worked inside the fuselage to ensure that the wing root attach point did not permit any droop. I actually gave them just a teensy bit of dihedral. Together, both of those efforts appear to have given me wings that are level. I agree that a spar of some sort - even just a brass rod - would not be a bad idea. These wings are light, so it does not have to be very beefy.

[Downen Scaled Replicas]

Paints have arrived! This will be my first time using the MCW brand of paints so I’m anxious to get started with them. On the far left are the two colors for the Global Hawk: Gunship Gray and White. The remainder of the paints are for upcoming UAV projects.

 

 

I’ve been working the wings with a heat gun and there is some improvement, but I’m not overly happy with the result.

 

 

It was suggested that the wings be made removable for transport. I like that idea AND it will give me the option of replacing them later if opportunity arises (more on that in a minute). Meanwhile, you can see in the picture how the wings are “trapped” between the lower and upper fuselage parts via four pins that fit into the wing roots. I have cut slots into the wing roots so that the wings can slide in and out of the fuselage.

 

 

Because I’m not happy with the wing droop on the Global Hawk, and because I really want to pose it in flight with the wings flexed up, I’m considering designing and 3D printing replacement wings for the kit. I’m starting to work with a 3D SLA printer which can print fine details in high resolution. I’ve designed a companion for the Global Hawk, a 1/48 scale Lockheed DarkStar, and now I’m starting to think that I might need to print a few things for the Global Hawk as well. Flight wings, perhaps an engine for a maintenance diorama… I’ll see.

 

 

Visit the Downen Scaled Replicas website or Facebook page if you want to see more about the DarkStar. Meanwhile, I need to start sanding on the Global Hawk… Thanks for watching. More soon...

Edited June 26, 2019 by Downen Scaled Replicas

[Mstor]

Let us know how the paint behaves. They look interesting. Airbrush ready gloss lacquers.

[Downen Scaled Replicas]

Some really cool progress to report today. First, I’ve mentioned that I’m not happy with the kit wings due to the droop and because I’m planning to pose the Global Hawk in flight. So, I modeled some new “flight” wings showing the 4-foot flex at the wingtip (full scale) designed into the wings for cruise flight. I printed them overnight and here are the first pictures. Top (planform) view (dark gray is the new 3D printed wing, light gray is kit wing):

 

 

The white lines show where the parts join; I had to print them in three parts due to the size limit of the 3D printer. BTW, these are SLA-printed, so the print lines are minimal and barely noticeable to the naked eye (the camera always over-emphasizes them). The camera angle in the photo also makes the new wings appear to be longer than the kit wings. This is not the case.

 

Bottom view showing the main gear bay fairing and gear door outline.

 

 

With these new wings, Droopy McCool has now become Joe Cool… (LOL):

 

 

These are designed to be plug-and-play with the kit (no modifications required), and can be removed when transporting the model. I am super-happy with the new wings, but I have a few tweaks to make to the design based on this prototype, then the wing set will be available for purchase at DownenScaledReplicas.com.

 

One more bit I accomplished this weekend was to paint the engine inlet and nozzle and get those parts installed so that I can close up the fuselage.

 

 

 

 

I used the MCW paints and I’m really impressed with how well these airbrush. They are easy to apply (no thinning required) and go on with a smooth finish that will be perfect for decals when I get to that point. I can’t wait to put these on the entire model; they are going to look GREAT!

[dnl42]

Those wings look great! I hope they stand up to creep; the kit's wings didn't.

 

I assume the MCW paints are lacquer. Yes? If so, I've been very happy with the fabulous finishes I get from Mr Color. As you note, quite smooth, with no need for a glossy clear coat prior to decals.

[Downen Scaled Replicas]

Yes, the paints are lacquers. They flow very well and give a great, tough surface for sanding, decals, etc. I use Mr. Color and like them as well. Lacquers are my preferred paint if I can get hold of them to use. It's becoming more and more difficult to get them in the States.

[Downen Scaled Replicas]

Back on the Global Hawk after taking a short break. The fit of the V-tails is not as positive as one might prefer; they can be installed at different angles so I held them against the grid on my cutting mat to ensure that I got both tails at the same angle. The base of the tails could use some work to blend them in.

 

 

Lots of interesting details on the top and side of the engine nacelle. I had to replace one of the antennas with a styrene disk because I sanded off the molded detail.

 

 

 

I cut a styrene rod to replace the nose gear bay doors; the kit parts were not going to fit well in the closed position.

 

 

All primed up and ready to go with the new wings.

 

 

And back to those wings. I made a few design tweaks to the original set and printed a new set which will actually go on the model. They are printed in three parts per side (six parts for a total wing set). When fresh from the printer they look like this (this is the left hand side wing only):

 

 

I will make these available very shortly via my website (www.DownenScaledReplicas.com), and when ordered the wings will already have the supports “rough trimmed”, so they’ll look like this:

 

 

 

You can see the support stubs still visible on the trailing edge of the wing parts and a few on the main gear bay fairing. All of these stubs are easily trimmed with a pair of sprue cutters, a hobby knife and/or sandpaper. The resin material is very easy to work with, so I recommend 400 grit sandpaper; anything rougher than that and you might find that you’ve gone through more material than you realize.

 

After about 10 minutes or so of cleaning up the support stubs, you’ll have a root wing section, mid section and outboard section that fit together with tab/slot joints. I’ve also designed-in a channel for a 1/16 inch diameter brass rod to help stabilize the wing over time and ensure that it does not droop (although I don’t believe there is much risk of that anyway). You can see the brass rod and trimmed parts in this photo:

 

 

The brass rod is 5-1/2 inches in length and spans from the inboard to the outboard section.

 

 

 

 

The wing root has been designed to match the kit’s root airfoil, and will slide right into the fuselage slot without any modifications to the kit (and this means that the wings will be removable for transportation):

 

 

When assembled, the kit wingspan is approximately 33 inches. WOW! (Camera perspective makes it look longer, but when measured it is 33 inches.)

 

 

 

Now everything is primed and ready for color. I’m going to do the traditional overall gunship gray with white upper wing surfaces. Hopefully I’ll have that soon.

[dnl42]

Nice! That really looks the part for an in-flight display!!! 

[CaptainObvious]

Those new wings really make the difference!
-co

[Downen Scaled Replicas]

Thanks dnl42 and CaptainObvious! I do really like the look so far.

 

Some white on the upper surfaces of the wings and gunship gray on the bottoms. I wasn’t sure just where the white and gray intersected on the wings, but several photos I was looking at seemed to indicate that the white might wrap under the leading edge of the wing. It also made things easier to mask while painting!

 

 

It’s hard to see in the previous photo the different shading that I did on the fuselage parts which are composite. I ended up masking and painting those parts straight dark gray, then coming back with a very thin / highly diluted overspray of the gunship gray to blend things together. Overall I’m happy with the look, but a few clearcoats and decals will really serve to tell if the effect works.

 

 

[Downen Scaled Replicas]

Wings and fuselage are both decaled and ready for flight!

 

 

 

The decals perform okay overall. They’re thick enough to withstand some rough handling during application, but not so thick that they don’t settle down well around details and in panel lines. My process includes using Micro Sol and Set, plus Solvaset in stubborn areas.

 

 

 

 

 

 

This kit is such a monster (33 inches from wingtip to wingtip!) that it was best for me to pose it in flight. I did not plan to design and print new wings, but it quickly became obvious that the kit wings with their built-in droop just would not work for me. So, I really like the effect given by the new in-flight wings which are now available for other modelers who might like to pose their Global Hawk in flight as well: www.DownenScaledReplicas.com

 

A complete video of this build is also available on YouTube: https://youtu.be/_apXWqjZIeg

 

 

 

The 1/48 Global Hawk posed next to my 1/48 scale Lockheed RQ-3 Darkstar. This is an original design and is currently also available at the website: www.DownenScaledReplicas.com

 

 

 

The Global Hawk kit is not a bad build. Overall the fit is good (be prepared to work on those seams, though) and the decal performance is average. I probably spent about 30 hours on the build itself, plus the time it took to design and build prototypes of the new wings which I had not originally planned to do.

 

Happy modeling everyone.

[dnl42]

Bravo! Well done.

[Downen Scaled Replicas]

On 8/18/2019 at 6:47 PM, dnl42 said:

Bravo! Well done.

 

Thank you! I appreciate it. This was an enjoyable build.