Build Thread: Nibiru Interceptor

[neil_w]

From the website of the Galactic Armaments Group:

The Galactic Armaments Group is proud to introduce the Nibiru Interceptor, a next-generation hybrid fighter craft designed for dominating the skies and​

beyond. With its revolutionary aerodynamic design and patented Plasma Core™ drives, this aircraft can operate seamlessly in the Earth's atmosphere and deep space, boasting a combination of speed and maneuverability that will leave the enemy chasing shadows.​

​

The Nibiru Interceptor features an array of advanced weaponry, including precision-guided Plasma Dart™ missiles and powerful ion cannons, providing its​

pilots with unparalleled superiority in any encounter. A proprietary cloaking system renders it nearly invisible to enemy radar, enabling it to fly undetected through enemy (air)space.​

​

This hybrid fighter represents the pinnacle of aerospace engineering and is designed to meet the demands of even the most challenging missions. Whether engaging enemy aircraft in the Earth's atmosphere or carrying out strategic operations in space, the Nibiru-X Interceptor is truly the ultimate weapon for air and space supremacy.​

​

Galactic Armaments Group: Hurling into the Future!™​

Vital Statistics:

• Length: 23.625"
• Diameter: 1.325"
• Mass: 3.1 oz (very optimistic, wouldn't be surprised to see it end up at 4 oz)
• Motor mount: 24mm
• Recovery: 15" parachute
• Skill Level: Expert (using the new Estes designations)

 

[jmasterj]

It has begun! I'm looking forward to seeing pictures of the construction solutions you chose/choose.

 

[neil_w]

A few random notes, before we get started

1. This design is almost seven years old, even before the start of my half-baked thread, back from the days of when I was actually coming up with some decent rocket designs. I've delayed starting it because (a) I wasn't satisfied with the paint scheme, and (b) I couldn't quite figure out how to build it. I still don't have everything completely nailed down but I'm comfortable enough with both of those situations to move ahead. We'll see how it goes.
2. The paint scheme is almost certainly not finalized, and I am still fiddling with it. I probably will not be completely satisfied with it fight up until it is finished. Suggestions welcome.
3. Despite my various dissatisfactions, this has always been one of my favorite designs. It is aerodynamically nonsensical but cool.
4. Joe Denay built a lovely upscale of this six years ago, with some enhancements/modifications. I may steal some of his ideas. I've already stolen the name (or the essence of it).
5. Thanks to ChatGPT for helping me compose the drivel in the first post above. I did clean it up a bit and add some of my own drivel, but the bones of it are from ChatGPT, and the fabulous company name "Galactic Armaments Group" is straight out of a list that it generated for me (slogan is mine, though. )
6. This build is going to take a while. My builds are generally pretty leisurely; this one might be even more so than usual. Just lettin' ya know.

OK, that should cover it for now.

 

[Charles_McG]

I think it's called 'puffery', rather than 'drivel'.

 

[BABAR]

​

Galactic Armaments Group: Hurling into the Future!™​

if it carries a video camera and it corkscrews, this could be literally true!

 

[Bruiser]

Looking forward to the build

-Bob

 

[neil_w]

Pod Tubes

For better or worse, I decided to slot and tab all the tubes and fins. The reason this is not simply "better" is two reasons:
1) Cutting TTW fins by hand is a bit fraught
2) The pod tubes won't have an inner tube, so the tabs-and-slots will be primarily for alignment.

In any case, I didn't really doing all this stuff with the pod tubes being plain old BT5, so I doubled them using @BABAR's favorite technique:

I had a piece of warped tube from my Mini A Heli, so i cut it into 3" pieces, and slice out enough so it could go inside the actual tubes. The reason I did it in two separate 3" pieces instead of one long one was that I thought a full-length insert would simply be too hard to manage.

I used Elmer's Glue-All for this... even still, once the piece was most of the way in it kind of stuck. I wanted to each end to be a bit indented in, because I have stuff to attach at each end. One of them resisted my pushing (using a spend 13mm motor), as you can see below.

These tubes are now much sturdier for handling, and should be able to handled the slotting without too much trouble.

 

[Starfire73]

Awesome work as always Neil!

 

[PaddyDaddy]

I know that Galactic Armaments Group is known for using
Variable Orbit Modulation Induction Technology
Will this ship have that?

 

[neil_w]

I know that Galactic Armaments Group is known for using
Variable Orbit Modulation Induction Technology
Will this ship have that?

Yes, absolutely. A whole range of proprietary technologies* are included, such as Yttrium-Atomic Kinematics and Bio-Alchemical Reactive Fuel Ejectors.

Still in development is the Hydrogen-Excited Antiproton Vacuum Engine.

Galactic Armaments Group: Hurling into the Future!™


*thanks again ChatGPT

 

[Sandy H.]

Glad to see another cool-as-heck Neil W build. I'd say I'm subscribed, but I don't know if that's a forum feature or not. Having said that, I'm sure I'll see updates as they happen!

Sandy.

 

[neil_w]

Pod Support Fins

I decided to go with basswood for my fins on this build, not for strength but because there is going to be a lot of delicate pieces an basswood is infinitely better at surviving rough handling than balsa. Fortunately I still had most of a nice sheet of 3/32" basswood on hand so I was ready to go.

I started with the pod support fins (yeah, that's an embarrassingly dumb name, but I don't know what else to call them.) These are four little guys with tabs on top and bottom. I decided to really try for precise fin cutting on this build. Here are my four cut fins:



The mini tabs are very messy because they don't need to be precise. Hopefully I did a better job on the full tabs. These fins are a good example of why I used basswood. They would have been very delicate as balsa.

I rounded the leading and trailing edges. Well, slightly; I didn't go whole hog but at least knocked down the sharp edges. Then of course I papered them. Here they are as the thin CA applied to the edges was drying:


And here is the finished set:

The full tabs really don't look perfectly square to me; I'm probably going to have to do some fitting there. Unfortunately I won't know until I have a slotted body tube to try them with (it'll be some time before I get there.) If I really botched them I'll just have to make another set.

Needless to say, laser cutting would be a big help here, but I don't have a cutter and enjoy the challenge of doing all this stuff old-school.

 

[neil_w]

Galactic Arms Group needs a logo (preferably, a tasteful one), if anyone wants to mess around.

 

[mbeels]

Looks great, I like this design.

patented Plasma Core™ drives

precision-guided Plasma Dart™ missiles

Will any of the Plasma Cores be shown as graphical features?

 

[neil_w]

Will any of the Plasma Cores be shown as graphical features?

No plans at present, although always subject to change. Threw that in the description just because I "had to", but without any particular forethought.

I think that the most plausible way to add plasma core graphics to this would be to add "slots" along the motor pods, but I haven't tried yet to see how it would look. As always, suggestions welcome.

 

[kuririn]

Yes, absolutely. A whole range of proprietary technologies* are included, such as Yttrium-Atomic Kinematics and Bio-Alchemical Reactive Fuel Ejectors.

Still in development is the Hydrogen-Excited Antiproton Vacuum Engine.

Galactic Armaments Group: Hurling into the Future!™


*thanks again ChatGPT

Don't forget the defensive weapons, like the Phased Unimatrix Kinetic Energy guns.

Galactic Arms Group needs a logo (preferably, a tasteful one), if anyone wants to mess around.

 

[BABAR]

Don't forget the defensive weapons, like the Phased Unimatrix Kinetic Energy guns.

I hope nobody has to get the NibuRuns between Saturn and Uranus.

 

[BABAR]

Revisiting design. Would it be a cosmeticmic atrocity to run the ring fin completely OUTSIDE the pods? Sure would simplify the build. Beauty however being in the eye of the builder….,

 

[neil_w]

Revisiting design. Would it be a cosmeticmic atrocity to run the ring fin completely OUTSIDE the pods?

Yes.

 

[neil_w]

Pod Cones

I purchased these little jet cones from BMS quite a while (like, years) back when planning this build:

However, I decided that these just didn't have the look that I wanted for this rocket. So I decided to try to transform them, and if I ruined them then I'd just replace them with 3D-printed cones or somesuch. Note that the one on the left is already CAed... I made the decision to rework them at rather at the last minute, after I had already started prepping them.

First I kind of rough-whittled them down like so:


And then I got to work with sandpaper. I got to this point and was pretty happy:


Then I realized that the whole thing was going to need to fit inside the BT5, so back with more sandpaper...


That's better. There's not a lot of shoulder left to glue them in, so I wanted a reasonably tight fit. A wrap of cardstock around the ends gave me that.


Let me tell you, the hardest part of this job *by far* was holding onto these little buggers. I must have dropped them 100 times. Eventually I had this idea which helped a bit, but it was still a struggle.

I then dry-fit one into the end of a pod tube (note the end of the tube had not yet been cleaned up, and yeah this is the look I was going for:


A coating of CWF and filler/primer followed.

 

[jqavins]

Pod Support Fins

(yeah, that's an embarrassingly dumb name, but I don't know what else to call them.)

Galactic Armament Group's patented Support Hybrid Integration Technology (GAG SH...) Or maybe"pylons".

 

[neil_w]

Or maybe"pylons".

Rocksim calls the fins that support a ring tail "pylons". I don't know if that applies here. I've also been having a hard time finding a definition of pylons that is relevant to rocket fins.

Maybe Bilateral Aerodynamic Radiator Fins.

 

[kuririn]

Pile-ons?
...
I'll excuse myself.

 

[Raythain]

Galactic Armament Group's patented Support Hybrid Integration Technology (GAG SH...) Or maybe"pylons".

They were called the Support Hybrid Integration Technology when they were still excremen.. *ahem* experimental.

Now they’re the Radiative Assistants and Large Pylon Hardpoints.

 

[neil_w]

Pod Tubes, again

Upon inspecting the BT5 stock I was using, I decided that the grooves were small enough that they might be filled just with filler/primer, and I could skip the usual CWF step. So I put on a pretty thick layer, sanded, and I think we're good.


Somehow, after sanding, I almost always end up with an area of less-sanded primer near the end, but an excessively sanded-off area right at the end of the tube. I haven't figured out why this is the case.

Oh, and one thing here that's a bit interesting, at least to me: most tubes have a primary groove and a much subtler, "secondary" groove that sometimes is easy to miss when applying CWF. This tubing actually had the primary groove, and then a secondary "ridge", easily visible in the primer pattern. Not sure I've encountered that before in round tubing.


As much as I hate sanding the stuff, filler-primer on body tubes serves double-purpose: smoothing out the spirals, but also the whole surface of the tube, which is not at all perfectly smooth when new. If you compare the feeling of an unfinished tube with one after applying and sanding the filler primer, you'll feel a huge difference.

Based on this success, I'm also not going to apply CWF to the main body tube. That BT55 has no spiral grooves that I can feel, at all. I don't even think I'll need a particularly heavy coat to smooth the whole thing out.

 

[jqavins]

I think that the most plausible way to add plasma core graphics to this would be to add "slots" along the motor pods, but I haven't tried yet to see how it would look. As always, suggestions welcome.

By that, I suppose you mean slots that allow stripes of plasma core to show through? What about such slots on the aft portion of the main tube, with narrower stripes along the RALPHs that indicate plasma being generated in the main body of the vehicle and conducted out to the engine modules to power them? Too Star Trek?

Somehow, after sanding, I almost always end up with an area of less-sanded primer near the end, but an excessively sanded-off area right at the end of the tube. I haven't figured out why this is the case.

I'm just speculating; here's what it looks like to me. The end of the tube, obviously, has a little more give than the middle. So the edge, when pressed on, flexes in a little. As you must keep the sanding block in contact with the tube, you unconsciously press in a little harder. That gives the oversnding at the end. At the same time, since one end of the sanding block is tipping down, the other end is tipped up, away from the tube, and thus you get undersanding there.

Oh, and one thing here that's a bit interesting, at least to me: most tubes have a primary groove and a much subtler, "secondary" groove that sometimes is easy to miss when applying CWF. This tubing actually had the primary groove, and then a secondary "ridge", easily visible in the primer pattern. Not sure I've encountered that before in round tubing.
View attachment 575235

I've seen that once. It's weird.

 

[BABAR]

Why don’t you just incorporate “Helical Ionic Conduits” in your next project, and highlight the spirals with a Sharpie?

also wondering, has anybody papered a TUBE? Okay, you will end up with a seam on one side, but that is longitudinally linear and could easily be incorporated in the decor. Kind of like the Christmas tree with one bad side you just place against the wall…..

 

[neil_w]

Fin Marking Guides

You lucky readers are now going to get treated to a whole (and rather lengthy) post about fin marking guides, because they were a mini-project unto themselves for this rocket. You're welcome!

OpenRocket helpfully generates fin marking guides for each body tube that has fins attached. For this rocket there are three problems:

1. OR is blissfully unaware of the points where the ring intersects with the pod tubes (I need marks for those)
2. The pod support fins are only connected (in the ORK file) to the main body tube, not to the pod tubes, so their position would not be marked on the pods
3. If I modify nothing but try to print the fin marking guides I get this:
   
   Oops.

Let's address #1 first. I wanted the two point where the ring intersects the pod tubes to be at 180 degrees. How to determine the position? Well, I could solve a pointlessly confusing trig problem, or I could do it the easy way: visually. I turned on the back view in OR, and zoomed in. Then I created a set of two tiny fins and added it to the pod, approximately at the angles where the ring would intersect. Then I tweaked the position of the ring up and down, and the angle of the finset, until they all intersected. The end result looked like this:

Now I have the position of the ring locked in, *and* a set of fins on the pod that will be shown on the marking guide. I named this finset "Ring Slot Placement".

Next I address #2 and #3 together. I created a new copy of the ORK file just for the pod marking guides (note that the left and right guides are different). I removed all the fins from the main body tube (so it wouldn't generate a guide), and added a new fin opposite the wing, to create a mark. This eventually looked like this:

Printing the marking guides from this file yielded what I wanted: one fully-marked guide for left and right pods:

Then I created yet another version of the ORK file, and this time deleted the pods. This left me with the third marking guide:


Whew.

 

[BABAR]

Fin Marking Guides

You lucky readers are now going to get treated to a whole (and rather lengthy) post about fin marking guides, because they were a mini-project unto themselves for this rocket. You're welcome!

OpenRocket helpfully generates fin marking guides for each body tube that has fins attached. For this rocket there are three problems:

1. OR is blissfully unaware of the points where the ring intersects with the pod tubes (I need marks for those)
2. The pod support fins are only connected (in the ORK file) to the main body tube, not to the pod tubes, so their position would not be marked on the pods
3. If I modify nothing but try to print the fin marking guides I get this:
   View attachment 575508
   Oops.

Let's address #1 first. I wanted the two point where the ring intersects the pod tubes to be at 180 degrees. How to determine the position? Well, I could solve a pointlessly confusing trig problem, or I could do it the easy way: visually. I turned on the back view in OR, and zoomed in. Then I created a set of two tiny fins and added it to the pod, approximately at the angles where the ring would intersect. Then I tweaked the position of the ring up and down, and the angle of the finset, until they all intersected. The end result looked like this:
View attachment 575509
Now I have the position of the ring locked in, *and* a set of fins on the pod that will be shown on the marking guide. I named this finset "Ring Slot Placement".

Next I address #2 and #3 together. I created a new copy of the ORK file just for the pod marking guides (note that the left and right guides are different). I removed all the fins from the main body tube (so it wouldn't generate a guide), and added a new fin opposite the wing, to create a mark. This eventually looked like this:
View attachment 575510
Printing the marking guides from this file yielded what I wanted: one fully-marked guide for left and right pods:
View attachment 575511
Then I created yet another version of the ORK file, and this time deleted the pods. This left me with the third marking guide:
View attachment 575512

Whew.

Your attention to detail puts you right up there with @lakeroadster .

of course, this is coming from someone who’s definition of “detail” is “de rear end of de chicken……”

seriously, I haven’t seen any other models with vertically (dorsal-ventral) asymmetric centered single ring fin, except maybe some that were attached direction to the main tube, like the CorkScrew.

do the flying surfaces have equivalent dorsal-ventral drag (I.e., aerodynamically symmetric even if visually asymmetric?) Not that it likely matters so long as the surfaces are all parallel to the rocket’s long axis.

 

[neil_w]

Your attention to detail puts you right up there with @lakeroadster .

Thanks, but in this case I'm not sure what choice I had. The geometry of this thing is pretty weird; exactly *how* weird wasn't obvious to me until I tried to figure out how the heck to mark the positions of the fins and ring slots. Without OpenRocket to help I'm not sure if I even would have attempted it.

Seriously, I haven’t seen any other models with vertically (dorsal-ventral) asymmetric centered single ring fin, except maybe some that were attached direction to the main tube, like the CorkScrew.

do the flying surfaces have equivalent dorsal-ventral drag (I.e., aerodynamically symmetric even if visually asymmetric?) Not that it likely matters so long as the surfaces are all parallel to the rocket’s long axis.

It is definitely a bit unusual, and one of the things I like about the design. My mindsim says that the drag and mass are balanced well enough that this thing will fly straight. Only one way to find out.