A neil_w inspired design...

[LithosphereRocketry]

I have always loved Neil_W's designs, but I don't typically like just building other people's designs. Therefore, I decided to put together a build with a Neil "look" to it while still being my own design. I will probably have access to a laser cutter soon, so I need to come up with something with crazy fins... I also love gap staging, so staged it is. I have lots of BT-50 lying around, so that gives me a tube size... Papered fins to support crazy shapes, etc.

Combining all of these aspects, I present...

...

...err, it doesn't actually have a name yet.

But it has a design!


The square crossfins are actually fintabs with no fin, so they don't sim. Additionally, they're the "wrong way", so they have to be square. The actual crossfins will interlock, like this:

The gap is intentional- I never do anything precisely, so I don't want to have to align them. Thus, an intentional 1/4" gap.

The booster borrows liberally from the Biohazard, but it has plates rather than a ring, so it has a different feel to it - more angles than curves.

The whole thing is so anti-3FNC that OR flatly refuses to sim it. No, really!


Therefore, I have two .ork's, one that sims but is ugly and one that doesn't but looks nice.

The paint scheme is definitely not set in stone, so feel free to suggest something else! Same with just about everything else, for that matter...

 

[K'Tesh]

1) NICE!!!
2) Get OR 15.03dev and you can do the fins the way you want to... kinda

 

[Charles_McG]

I like the two stage stealth photon disruptor vibe.


Sent from my iPhone using Rocketry Forum

 

[LithosphereRocketry]

1) NICE!!!
2) Get OR 15.03dev and you can do the fins the way you want to... kinda

Does it save now? I heard it was having problems with that before.

Sent from my LGL44VL using Rocketry Forum mobile app

 

[neil_w]

Very nice, like it a lot!!! I've been wanting to do a 2-stage design for a while and this really hits a lot of the points I would have been trying for. You can definitely tighten up that 1/4" gap though.

The new OR would be able to handle this design, since your pods are in groups of 3 and symmetrical.

When I get a chance I'll have a look at the ORK files.

(not sure I really need credit in the thread title)

 

[K'Tesh]

Does it save now? I heard it was having problems with that before.

Depends... I'd guess not... well, not as you'd hope. To do the fins, you'll need to have pods set to 1 more than likely. Once you've got the fins and everything where you like, make a note of the location in either the comments, or the name of the component on the offsets, and angles. OR will probably set your pods to 2 by default, and zero the offsets and angles when you save, close, and reopen the file again. Flight characteristics will be highly suspect.

Oh, and you'll not be able to scale a fin (after importing it from an image). I suggest using the older version of OR to import the fin shape, and scale, then copy it, and paste it into the developer's version.

 

[Nytrunner]

The new rocket chic......Neil-Scale!

I wonder how Rocksim would handle this form.

 

[neil_w]

Played with the design in new the new OR today, indeed it doesn't handle the angles of fins on pods correctly, so you'd need to do three separate individual pods, which is totally not worth the trouble so I dropped it there.
For what it's worth, I found it a bit more pleasing to my eyeballs to move the transition back a couple of inches.

I have to say I am totally digging this design. Look forward to seeing the build!

 

[LithosphereRocketry]

Played with the design in new the new OR today, indeed it doesn't handle the angles of fins on pods correctly, so you'd need to do three separate individual pods, which is totally not worth the trouble so I dropped it there.
For what it's worth, I found it a bit more pleasing to my eyeballs to move the transition back a couple of inches.

I have to say I am totally digging this design. Look forward to seeing the build!

Thanks!

The main tube length is pretty much fixed - it uses exactly one 18" tube. I'll try stretching the fore tube next time I'm at a real computer though.

Sent from my LGL44VL using Rocketry Forum mobile app

 

[LithosphereRocketry]

I like it! Thanks for the suggestion, Neil! You definitely get credit for this design... It steals liberally from just about all of your recent designs!

 

[LithosphereRocketry]

So... I might actually build this thing...

I got fins laser-cut today. No pics yet, I'll post them later.

Yes, laser cutting is amazing. But these could've turned out better. I'm not sure if it wasn't focused correctly or what, but it cut a fairly large groove in the wood compared to what I've seen in the past. Of course, this is the one model where parts actually have to fit together well. It'll work fine.

The other problem is that the fan that clears the smoke away from the cutting area started blowing the already-cut fins around. Not a good time. A few fins got a little scorched when they flopped too close to the laser. No biggie, just annoying.

The one really disappointing thing...

I just realized I forgot the little nose strakes in my laser file. :bangpan: :bang:

Again, not anything horrible. They're simple and mostly along the grain, so they shouldn't be hard to cut by hand.

I already have plans for a BT-70 upscale as an excuse to get into electronic staging... Don't know if/when that'll actually happen.

In other news, I thought up a bit of backstory... This is a commercial spaceliner based on a standard LH2 engine in the first stage and a horrifically toxic but efficient nuclear sustainer. The first stage gets it up to a high enough altitude so that those on the ground aren't harmed... Then it drops away and SpaceX-es itself using three weak but efficient airbreathing engines on its fins. How does the sustainer get back? No clue. I'll get back to you on that one.

 

[LithosphereRocketry]

Picture time!

Aforementioned laser cut fins, sans nose strakes:

Also some tubes and the Tomahawk's cone for scale...


I decided not to paper the fins- they felt strong enough as-is. They're also extremely light and easy to sand, so I decided to airfoil them. How did I trick myself into that?

Being the idiot I am, I of course rounded several spots where the fins will eventually glue together.


Next step will be brushing off the Xacto knife- those tubes and fins won't cut themselves!

 

[neil_w]

That is a fine looking load of lumber ya got there. Look forward to seeing this come together!

 

[LithosphereRocketry]

So I got a bunch done but my thread updating is behind schedule.

First step was to start fabricating a few parts. Rummaging around in my parts box, I realized that I didn't have any BT-50 couplers. So I repurposed a bit of tube that got a "hook zipper" when a booster didn't tumble quite as much as I would have liked. I glued a strip of scrap paper to either side of the seam and let it dry inside a tube. Came out nicer than I expected. I also made an engine block from a motor casing. 29mm retainer for scale.


Next thing I forgot to check if I had: Centering rings. Luckily I had about a million (alright, 6) 5-50 CR's, so I just tore out the middles. One even came out nice enough for another engine block! I was already epoxying for another build so I also glued the shoulder onto the NC.


Then I glued the strakes onto the main booster fins- the other booster fins have strakes too, but they're too thin to stay on before I glue the fin to the BT.


I also did a bit of work on the MMT/stuffer system. Both stages will use homemade engine hooks, which I thought I got a picture of- apparently I didn't. You can see them OK in these pictures. The front end of the booster stuffer is notched to accept the hook.

Yes, someone is going to complain that I put finger tabs on my engine hooks. I personally like finger tabs, especially with wiper-blade hooks that are stiffer than standard. The sustainer hook has a low-profile tab to fit better in the stuffer.


One more small step- put together the transition/upper BT assembly.

 

[neil_w]

Good progress, I like the way the two motor mounts fit together. But don’t forget to vent the booster motor mount, since you’re gap-staging.

 

[LithosphereRocketry]

Good progress, I like the way the two motor mounts fit together. But don’t forget to vent the booster motor mount, since you’re gap-staging.

My plan is to drill a 1/8" hole through the entire diameter of the booster once I get the MMT installed. Any reason not to? I've gap staged 18mm with 2 1/8" vents before... Admittedly, the booster CATOed. But it still lit the sustainer!

 

[LithosphereRocketry]

Just remembered, I still need a name. I'm open to suggestions!

 

[neil_w]

My plan is to drill a 1/8" hole through the entire diameter of the booster once I get the MMT installed. Any reason not to? I've gap staged 18mm with 2 1/8" vents before... Admittedly, the booster CATOed. But it still lit the sustainer!

That seems fine, sounds like you have it well in hand.

Admittedly, it seems to me like making the holes in the MMT before it’s installed would be easier, and anyway the holes in the MMT and outer BT don’t need to be aligned. But if you’re comfortable drilling through the whole assembly then go for it.

 

[LithosphereRocketry]

That seems fine, sounds like you have it well in hand.

Admittedly, it seems to me like making the holes in the MMT before it’s installed would be easier, and anyway the holes in the MMT and outer BT don’t need to be aligned. But if you’re comfortable drilling through the whole assembly then go for it.

I might go for the drill-separately option. The only issue I would worry about is catching the fore CR with the drill hole.

Seriously, though. This thing needs a name.

 

[neil_w]

Names are Hard. I have a better feel for names for my own designs because I know what I was thinking during the design (still not always easy). But I shall ponder.

 

[GlenP]

I like the interlocking tip fins on the interstage.

For the booster tumble recovery, can you check c.g. and c.p. of the booster alone? Might have to balance that after built with a spent engine casing to make sure you get a good tumble rather than a lawn dart. Or, go Black Widow style and trim that thing for glide!

 

[LithosphereRocketry]

I like the interlocking tip fins on the interstage.

For the booster tumble recovery, can you check c.g. and c.p. of the booster alone? Might have to balance that after built with a spent engine casing to make sure you get a good tumble rather than a lawn dart. Or, go Black Widow style and trim that thing for glide!

I've already learned to do that the hard way... I'd attach a picture but my phone won't upload images for some reason.

Long story short- I built a gap staged Boosted Arcas but didn't tumble check my booster. Shoved the stuffer/lattice assembly up the tube. D12-0 made a nice zipper via the engine hook, giving me lots of free coupler material. The booster lived to fly again- with rear ejection.

Sent from my LGL44VL using Rocketry Forum mobile app

 

[neil_w]

[posted to the wrong thread, darnit]

 

[neil_w]

For hard-to-explain reasons, the name "Splinter" has been stuck in my head for this rocket.

 

[LithosphereRocketry]

For hard-to-explain reasons, the name "Splinter" has been stuck in my head for this rocket.

What will happen when those booster fins hit the ground?

By the way, I noticed a mistake I made with the fins on this rocket. A big round of applause to anyone who can figure out what it is... I'll give you a hint- you can't figure it out without using the OR renderings in the OP or post #10 (revised fore section).

 

[LithosphereRocketry]

A bit of progress... Got the fin lines marked on the BTs.



Still no takers on the stupid mistake in post #12 (easier to see in post #14)?...

 

[dmgrime]

Staging coupler in aft end of sustainer MMT? No way to insert/secure sustainer motor?

Sent from my SM-G920V using Rocketry Forum mobile app

 

[LithosphereRocketry]

Staging coupler in aft end of sustainer MMT? No way to insert/secure sustainer motor?

Sent from my SM-G920V using Rocketry Forum mobile app

Nope, try again. Good idea though.

Sent from my LGL44VL using Rocketry Forum mobile app

 

[LithosphereRocketry]

Lotsa progress, complemented by thread updating laziness...

Installed the MMTs and drilled vents. Could've gone better, but it worked OK.
View attachment 334490
View attachment 334491

Attached strakes to the sustainer. Pretty easy.
View attachment 334492
View attachment 334493

Glued the tubefins onto the main booster fins. I took pictures of all 3 but they all pretty much look like this.
View attachment 334494

So important life lesson here: Don't Titebond on aluminum.

I was gluing the T fins together, so I started with Elmer's wood glue since I'm trying to get rid of it in favor of TBIII. That worked fine. But on one, I already had the Titebond out, I decided to use that instead.
View attachment 334495

News flash- TBIII sticks to aluminum. Not well, but given the amount of surface area touching the angle, it was enough to make pulling the fin off a nightmare.

I have a picture of the slight damage but I can't attach it for some reason- I'll try again later.

Long story short- attached the sustainer T fins.
View attachment 334496
View attachment 334497

Starting to look llike a rocket!

Sent from my LGL44VL using Tapatalk

 

[LithosphereRocketry]

More progress- attached the T fins to the booster.


Still looking for a name for this thing...

Sent from my LGL44VL using Tapatalk