Gatchaman (Battle of the Planets) God Phoenix Spaceship

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BigMacDaddy

BigMacDaddy

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So what do you guys think, can this [theoretically] be made stable? I don't want to put a huge tube out behind it or anything but might make it a bit longer or make top fins a bit larger for example. I would plan 2x engines in the back so could go with 18mm or 24mm so could be somewhat heavy (which it will be with all those 3D printed parts and necessary nose weight).

Next question is, what parts can I replace w/ 2mm basswood, standard body tubes, etc... to keep weight down? Easy parts: 2mm basswood = Fins & Wings + Vertical wing pasts in middle. Body Tube: center portion of wing pods. 3D Printed = Nose cone, front/rear of wing tip pods, top pod slotted for top fins, vents, transitions. Questionable: Wondering if I can make the body out of rectangle(s) of basswood (possibly mounted on a 3D printed frame).

This is actually one of my favorite shows from my childhood. Some pictures of the "prototype" to inspire us...

1634084504840.jpeg

1634084513451.jpeg 1634084529786.jpeg1634084520936.jpeg
 
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I think it is doable. The bass wood body could have a balsa frame. Build it like a wall for a house, beams and cross members. As far as stability. It is going to have a lot of base drag. Especially with those intakes. Probably need shear pins to hold the nose cone on. Because of the base drag you might not need a full caliber between the CG and CP. My concern would be with the dropped nose. But then the fins may counteract the nose shape. Give it a shot. If it doesn't fly you still have a good looking model.
 
I suspect rear-ejection?

Also, looking at this:
1634084529786.jpeg
... the motors seem very off-centered toward the bottom. I think the bigger the rocket, the greater the issue.

I'd say if you're willing to spend weeks or months on the project, then go for it!
 
Funkworks said:
I suspect rear-ejection?

Also, looking at this:
View attachment 485945
... the motors seem very off-centered toward the bottom. I think the bigger the rocket, the greater the issue.

I'd say if you're willing to spend weeks or months on the project, then go for it!
Click to expand...

Good point about the motors being off-center. I may be able to fix that somewhat.

I can also straighten the nose out some (would still be asymmetrical to maintain the look but could angle it so bottom is straight at least.

I wonder if the curved nose would offset the additional top drag...
 
teepot said:
. If it doesn't fly you still have a good looking model.
Click to expand...
that depends on HOW you proved it couldn’t fly.

If it fails the string test and becomes an instant hanger queen without even a whiff of propellant, then yes.

If you take the @Daddyisabar “away pad” let’s just launch it and see what happens, then perhaps not…..
 
This would be a fun model but I cannot see a way to break it down into a simpler number of parts.

What do those companies that make square rockets make the rectangular airframes out of? There are a number of models that would be possible if I had inexpensive rectangular airframes to work with...
 
BigMacDaddy said:
This would be a fun model but I cannot see a way to break it down into a simpler number of parts.

What do those companies that make square rockets make the rectangular airframes out of? There are a number of models that would be possible if I had inexpensive rectangular airframes to work with...
Click to expand...
Newway uses convolute wound paper tubes. Presumably they just us a square mandrel, although there may be more to it than that. The walls are somewhat thicker than the typical round tubes.
 
neil_w said:
Newway uses convolute wound paper tubes. Presumably they just us a square mandrel, although there may be more to it than that. The walls are somewhat thicker than the typical round tubes.
Click to expand...
Do you (does anyone) know if you can buy just the tubes? (although for this model I would need a rectangular tube for the main body)
 
neil_w said:
Newway uses convolute wound paper tubes. Presumably they just us a square mandrel, although there may be more to it than that. The walls are somewhat thicker than the typical round tubes.
Click to expand...
I had thought that New Way was buying them from a manufacturer because I think I've come across similar square tubing in the past, but can't recall for what. Regardless it would be a specialty item and likely much more expensive.
BigMacDaddy said:
Do you (does anyone) know if you can buy just the tubes? (although for this model I would need a rectangular tube for the main body)
Click to expand...
It should be easy enough to fold your own out of cardstock or cardboard (score inside edges).
 
BigMacDaddy said:
Good point about the motors being off-center. I may be able to fix that somewhat.

I can also straighten the nose out some (would still be asymmetrical to maintain the look but could angle it so bottom is straight at least.

I wonder if the curved nose would offset the additional top drag...
Click to expand...

Neat concept.

You may want to leave the motor(s) offset below the rockets c/l. The design has a slanting nose and body, which will make the rocket nose dive. The offset thrust will help to counteract that.

As far as the cardboard tube... why not just 3d print the entire rocket? It won't be to heavy for a G80T motor. :clapping:

This rocket would be quite the challenge to replicate in Open Rocket... A series of horizontal pods using multiple transitions to form an arcing profile.... gnarly :clapping:
 
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lakeroadster said:
Neat concept.

You may want to leave the motor(s) offset below the rockets c/l. The design has a slanting nose and body, which will make the rocket nose dive. The offset thrust will help to counteract that.

As far as the cardboard tube... why not just 3d print the entire rocket? It won't be to heavy for a G80T motor. :clapping:

This rocket would be quite the challenge to replicate in Open Rocket... A series of horizontal pods using multiple transitions to form an arcing profile.... gnarly :clapping:
Click to expand...
Yes, 3D printing the whole thing would be possible. And actually it is possible to keep the weight relatively light (basically print a hollow shell that is only a couple of layers thick). More or less the issue becomes design -- need to keep all your design elements slanting upwards or it will need lots of supports (or creativity to build in some supports). It is just a bit time consuming to do this -- although I have been learning some tricks to make printing faster. Maybe this is the route I will go when I get back to this design.

Given that this has two engines in the "real" thing, a pair of 24mm engines can lift quite a bit.
 
KenECoyote said:
How about internal round tubing as the main construction with a thin outer shroud for the midsection?
Click to expand...

If I wanted to keep weight and print time down this is basically what I would do. Maybe a BT-60 main tube with 3D printed frames that would be used to mount cardstock on (for the main square body -- which is actually tapered in the "real" thing). Nosecone would insert into BT-60 tube and tube would hold parachute. I would 3D print motor mounts and funnel to feed 2x 24mm motor ejections into the BT-60 tube.

Still quite a bit of 3D printed details so not sure how much weight this would save ultimately (although it saves a ton of print time).

Whole model would make an interesting cardstock model but that is not my expertise.
 
lakeroadster said:
Neat concept.

You may want to leave the motor(s) offset below the rockets c/l. The design has a slanting nose and body, which will make the rocket nose dive. The offset thrust will help to counteract that.

As far as the cardboard tube... why not just 3d print the entire rocket? It won't be to heavy for a G80T motor. :clapping:

This rocket would be quite the challenge to replicate in Open Rocket... A series of horizontal pods using multiple transitions to form an arcing profile.... gnarly :clapping:
Click to expand...

I am not sure how this would model in OpenRocket (I can get it to visualize but not sure the CP calculation would be useful). I would likely leave the wing vents open through the model to function as ring fins. I am pretty confident that this would be stable if CG is in front of the vents and probably stable if CG is in front of the outer wing portions (but getting riskier). I guess I would build it and swing test with increasing amounts of nose weight.
 
BigMacDaddy said:
Yes, 3D printing the whole thing would be possible. And actually it is possible to keep the weight relatively light (basically print a hollow shell that is only a couple of layers thick). More or less the issue becomes design -- need to keep all your design elements slanting upwards or it will need lots of supports (or creativity to build in some supports). It is just a bit time consuming to do this -- although I have been learning some tricks to make printing faster. Maybe this is the route I will go when I get back to this design.

Given that this has two engines in the "real" thing, a pair of 24mm engines can lift quite a bit.
Click to expand...

That 1st photo of an actual model has a much better look than most of the models I'm finding online. Any idea where you got that photo from? Is that a model that you could purchase, to pull dimensions from, to create the CAD model?

1676554297624.png
 
lakeroadster said:
That 1st photo of an actual model has a much better look than most of the models I'm finding online. Any idea where you got that photo from? Is that a model that you could purchase, to pull dimensions from, to create the CAD model?

View attachment 563659
Click to expand...

I think this is a new version of the God Phoenix (I needed to add in the God to find it)... Academy made the model (I think).

www.facebook.com/media/set/?set=a.2683851485211511&type=3

Looks like around $50 which is not bad.

www.ebay.com/itm/265400756131
 
Depending on how much you will deviate on looks, especially on the sloped nose, this is a fairly straightforward airplane oddroc. No problem, easy peasy lemon squeezy, kid tested, mother approved.

To get decent performance, strength and reusability, it would take some time and old world building techniques. Only the patience of a Jedi will work. Light and strong papered balsa & card stock on the hind end. Heavy hand shaped plastic epoxy clay up front. Put the gear down to offset asymmetric drag. Funnel ejection for traditional two chute deployment or go with hipster rear eject. All the grumpy old dudes will be enthralled!

Then there is the Dark Side. Just 3D print and stick in some composite motors. Fly like a PMC! Easy, fast machine construction while drinking as many Sunny D juice boxes as possible. Instant gratification using modern, high tech manufacturing techniques. Get in a lot of good video gaming while it prints. Who cares how it flys, a participation trophy is waiting along with a pizza lunch. So lucky the kidz these days!
 
BigMacDaddy said:
Otherwise I guess I need to start investing in some more cardstock for building models.
Click to expand...
I have bought just tubes from NewWay.

You’d have to contact them either by email of a contact on the website. Price was reasonable, but it’s been several years and inflation has hit everything. Alternative is buy a kit and kitbash it.
 
Didn't New Way say at NARCON that they were having a hard time getting square tubes, and some of their new kits would use round ones?
 

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