Neil_W's half-baked design thread

[PatD]

Hey buds,
Did you see the latest Apogee Newsletter? There's a finishing technique that's really cool. No spoilers, but the first thing I thought of was your designs. Let me know what you think.
https://www.apogeerockets.com/education/downloads/Newsletter525.pdf

I wonder how much weight that adds. Excellent finishes tho.

 

[neil_w]

How about an embedded floating plasma ball? Never mind how to properly decorate that ball for now.

 

[mbeels]

How about an embedded floating plasma ball? Never mind how to properly decorate that ball for now.

That would be really cool. Are you thinking of having in invisibly supported, like with fishing string or something? The floating effect would be a head turner.

 

[neil_w]

That would be really cool. Are you thinking of having in invisibly supported, like with fishing string or something? The floating effect would be a head turner.

No, it'd have to have a tube running through it. How convincing the floating effect would be is hard to say.

I was thinking that could be a replacement for the plasma core in the Radiant, could make it more interesting.

 

[jqavins]

But why not a fishing line running through it? That would give a much better chance of a good floating effect. On the other hand, you could incorporate the tube into the design concept; hot gas is injected through the small tube at the forward end, compressed and ionized by the EM fields generated within the surrounding structures, and plasma is tapped off through the aft small tube for acceleration by more EM fields out the nozzle.

 

[BABAR]

Since you have “re-done” a classic with your SkyWriter, how about redoing the “Pop Fly”. I had the original, the design was kind of cheesy.

Except do it to scale, Major League Baseball bat and ball. Use a real ball for the nose, for safety reasons I would recommend It come down by chute, either attached to or separate from the bat.

Call it the Louisville Slugger, or since your from Joizy, the Yogi Berra

I looked up weight of a baseball on Wikipedia


Under the current rules, a major league baseball weighs between 5 and 5 1⁄4 ounces (142 and 149 g), and is 9 to 9 1⁄4 inches (229–235 mm) in circumference (2 7⁄8–3 in or 73–76 mm in diameter).

I have done some designs like this, running the rod/lug THROUGH the ball makes a much more secure rocket on the pad.

 

[neil_w]

But why not a fishing line running through it?

1) The rocket needs to hold together.
2) There needs to be a path for ejection gasses. This would be pretty close the rear of the rocket, I doubt there would be room for rear eject.

 

[jqavins]

1) Those ribs around the ball would hold it together.
2) Yeah, good point.
2a) One could use electronic deployment, but I know that is not your way.

 

[boatgeek]

1) The rocket needs to hold together.
2) There needs to be a path for ejection gasses. This would be pretty close the rear of the rocket, I doubt there would be room for rear eject.

Volunteering you for more work...

What about mitered tubes to carry the ejection gases forward? I'm thinking a 3-part section with tubes at +/- 45 degrees to the main axis, and a short piece parallel to the main axis. With some filled in fins along the lines of what you have above, it would be pretty strong too.

 

[BABAR]

1) The rocket needs to hold together.
2) There needs to be a path for ejection gasses. This would be pretty close the rear of the rocket, I doubt there would be room for rear eject.

Put the ball in a “cage” of BT-5 bars. Ball can freely rotate. Maybe make the cage a little long so it can bounce up and down.

Run the ejection gases through the BT-5s.

Presto, Ball Cage and Baffle, all in one swell foop.

 

[BABAR]

Volunteering you for more work...

What about mitered tubes to carry the ejection gases forward? I'm thinking a 3-part section with tubes at +/- 45 degrees to the main axis, and a short piece parallel to the main axis. With some filled in fins along the lines of what you have above, it would be pretty strong too.

You beat me!

 

[jqavins]

Electronic sounds a whole lot easier to me. And a cage of six BT5-based assemblies like that would get quite large. (Of course, I'm the one who some posts back suggested going large for the mothership.)

 

[neil_w]

I could imagine doing it with 3D-printed curvy tube, but not with little pieces of BT5. They would also tend to obscure the view of the ball somewhat.

Not interested in doing electronic deployment.

Also I couldn't model it in OR in any reasonable way.

 

[jqavins]

BT5s wouldn't obscure the ball if you scale up. If one were to make the angled portions long then they also get far apart. Then use a bigger ball to suit. But that's why I was thinking it would get big. Even 3D printed, you'd need a reasonable minimum ID of the channels, and length to gain separation for visibility, and that would force the overall size.

And yeah, I know that you're not interested in electronics. I just think that would be the only practical way. Other than the tube up the middle that you've already decided on anyway. And I doubt you'll be able to hide that, so you might as well embrace it.

 

[boatgeek]

Electronic sounds a whole lot easier to me. And a cage of six BT5-based assemblies like that would get quite large. (Of course, I'm the one who some posts back suggested going large for the mothership.)

I was thinking more of 3-4 BT-5-ish tubes.

I could imagine doing it with 3D-printed curvy tube, but not with little pieces of BT5. They would also tend to obscure the view of the ball somewhat.

I'll volunteer if you need someone to put together a 3-D model for printing. I have some good tools for that from work.

 

[neil_w]

I'll volunteer if you need someone to put together a 3-D model for printing. I have some good tools for that from work.

Thanks. Long way away from actually thinking about a build.

 

[neil_w]

Here it is with a black BT50 stuck through the middle, and the BT55 extended to cover it.

To me, that's good enough to continue exploring. Still a loooooong way from anything resembling a completed design, still just noodling.

 

[neil_w]

Here it is with the Radiant wings:


Has potential I think. Definitely a more interesting look for the Radiant, which I've been wanting to "finish" for a long time.

 

[mbeels]

Here it is with a black BT50 stuck through the middle, and the BT55 extended to cover it.

Nice, I like it. It definitely gives the illusion of floating, the BT-50 won't be easy to see. I'd almost want to open up the gap between the ribs and the ball, so as the ball is viewed at different angles, there is always a gap visible between the ball and the ribs. Maybe that is the case currently.

 

[neil_w]

Nice, I like it. It definitely gives the illusion of floating, the BT-50 won't be easy to see. I'd almost want to open up the gap between the ribs and the ball, so as the ball is viewed at different angles, there is always a gap visible between the ball and the ribs. Maybe that is the case currently.

Fewer ribs would help in that regard:

That opens it up but the cage is a bit less cool-looking I think. Not sure whether it's net positive or not. What do you think?

 

[mbeels]

That opens it up but the cage is a bit less cool-looking I think. Not sure whether it's net positive or not. What do you think?

I don't know. What does it look like with 6 slightly larger ribs?

 

[neil_w]

 

[mbeels]

Hmm..... I think I definitely like the 6 ribs better than 4. Maybe a slight preference for the larger ribs, but not a terribly big difference. Hard to say.

 

[Nytrunner]

Bonus points if you know where apogee jacked that image from for their cover

 

[BABAR]

If the central tube is longer than the ball, and the central hole in the ball is bigger than the outer diameter of the tube, then the ball could both rotate axially and bounce forward and back. Could out a bigger body tube along the ball that slides back and forth on the central gas channel.

I have done pop pods for min diameter rear eject boost gliders with the central “chimney” smaller than the motor mount. I lined the internal surface with rolled up soda can just forward of the motor (the smaller diameter gets toasted by the ejection charge if you don’t. So you CAN channel the ejection charge of a larger motor through a relatively small tube.

Not sure the degree of motion you would get is really worth your while.

I think for the effect you are going for, you really need to consider LED lights and a dusk or nighttime launch.

 

[Senior Space Cadet]

It's pretty obvious that a lot more can be done with Open Rocket than I'm capable of. I've barely scratched the surface. Neil seems to be the Yoda of Open Rocket.
I've got a lot more learning to do.
Hopefully, some day, I can come close to Neil's skill, then I can show you how twisted my mind really is.

 

[dhbarr]

It's pretty obvious that a lot more can be done with Open Rocket than I'm capable of. I've barely scratched the surface. Neil seems to be the Yoda of Open Rocket.
I've got a lot more learning to do.
Hopefully, some day, I can come close to Neil's skill, then I can show you how twisted my mind really is.

@K'Tesh apparently made some kind of deal with the devil in this regard, viz.
https://www.rocketryforum.com/threads/kteshs-openrocket-files.123564/page-17#post-1942850

 

[Senior Space Cadet]

Here's an idea that I've been working on, but can't seem to get it to work. Even without a motor, CP is ahead of CG. Neil's would actually fly.

 

[jqavins]

OK, first, I stand corrected on the ability to hide the tube through the ball. The main tube coming in close and the small flares at the ends really do the job well.

Six ribs rather than four is hands-down better.

If Neil is the Yoda of OR then K'Tesh is Palpatine. But less evil. As far as we know.

As for the above design, I've tried designs like this before, as have many others I'm sure. The main problem with them is that the fins are too tall. Because the geometric centroid of the fin's planform is so far forward they don't move the CP as far aft as they need to. In other words, your CG is fine, but you have a CP problem.

I suggest starting a new thread, so as not to hijack Neil's half baked design discussion.

 

[neil_w]

If the central tube is longer than the ball, and the central hole in the ball is bigger than the outer diameter of the tube, then the ball could both rotate axially and bounce forward and back. Could out a bigger body tube along the ball that slides back and forth on the central gas channel.

Having the ball be loose would be an interesting novelty but not in any way related to being a plasma-ball-thingie in a preposterous sci-fi design.

I think for the effect you are going for, you really need to consider LED lights and a dusk or nighttime launch.

Now that's a whole lot more interesting. I had a similar thought for PDII, although the inner core tube was essentially minimum size so there'd be no place to put LEDs inside. This one would have room inside the ball.

Unfortunately, I have zero prospects for attending a night launch, so if I lit a rocket like this it would purely be for my own amusement, not that there's anything wrong with that.

Decorating the ball is already a vexing problem here, now you'd have to add the requirement that it be translucent, which would probably dictate clear decal paper. How do you cover a ball with decals?

In any case this is putting the cart way before the horse. Goal is to get to a decent-looking design first, then worry about that other stuff. There is still a lot of do here. I like it as a starting point, but that's all it is for the moment.