MX-570 / JB-3 Tiamat (3D Printed + Plywood + Cardboard Body Tubes)

[BigMacDaddy]

I know a couple of folks on here have made this one but at the urging of @CTimm I am gonna have a go at making one from 3D printed parts. I am gonna make the clustered booster version (there is also a single engine booster version, but that one looks too much like the R1 that I already made). There are not too many pictures of the real thing out there but here are some.



I mostly worked off of this diagram:


Here is what I have so far -- what do you guys think? 18mm motor in sustainer, 13mm mini engine cluster in rear around a single 24mm mount in center (designed to have BT-5 tubes used in rear to keep weight down). I can easily drop the center booster mount down to a 13mm as well (or 18mm) but it is pretty convenient to launch with a single 24mm in booster in some cases. I have not setup all the motor mounts / retainers yet so could easily setup the 24mm mount so you could screw in dummy plate that would convert between 24mm and 13mm. 47.5cm (almost 19”) long and 16.3cm wide

 

[CTimm]

Wow!
Looks very nice!

Possibly facet the booster fins (see photos 20C, 25C, and 27C) and size the cluster tubes for paper tubes to be sleeved?
That would be a sizable one-piece fin can!

 

[BigMacDaddy]

Wow!
Looks very nice!

Possibly facet the booster fins (see photos 20C, 25C, and 27C) and size the cluster tubes for paper tubes to be sleeved?
That would be a sizable one-piece fin can!

Thanks -- yes, the rear booster is setup so that all those tubes would be BT-5 tubes (I just put placeholding tubes in there but that actual 3D printed part has tube cut outs). I usually ignore fin profiles and do flat plywood fins but will do a version w/ 3D printed fins for both booster and sustainer.

 

[David Schwantz]

Go for it. Looks like a great flying project to me

 

[BigMacDaddy]

Do you guys think that museum pieces are ever "after market" - in other words are mocked up for display or rebuilt when parts are not available? Many of the rockets or parts of rockets that I see in some displays seem to just be sheet metal and do not quite have the finishing I would expect of a launched rocket. I always assumed that the museum might rebuild or even scratch build a part if they did not have the [entire] original and wanted to display it. Am I wrong about this?

In this case that yellow booster (and maybe the whole rocket) in the Wallops display looks a bit different than the photos of the actual launch -- this rocket was the 1st test launch ever done at Wallops which is pretty cool so I can imagine they want to display it. I can also imagine that the rocket may not have survived its actual flight.

 

[David Schwantz]

Must of the ones that I have seen will say if they are original or a copy. For example, the Saturn V that sits on the outside at Huntsville is a mockup. But the parts inside are actual, I believe.

 

[kenstarr]

Looks awesome! I can't wait to see the finished product.
Ken

 

[lakeroadster]

Have you attempted an Open Rocket simulation? Seems like a good idea to have the canted motors aligned with the rocket cg... but it looks like that would be way to far forward?

 

[BigMacDaddy]

Have you attempted an Open Rocket simulation? Seems like a good idea to have the canted motors aligned with the rocket cg... but it looks like that would be way to far forward?

Thanks for reminder -- I had not previously but did just do one. This is very rough as I am not sure how much 3D printed parts (particularly in the rear) will weigh. However, having a rough idea of where CP winds up helps me imagine how much nose weight I will need. The booster engines are on the 10 degree angle. I think the prototype was around 8 or 10 degrees.

 

[lakeroadster]

That is one weird looking rocket... no slam on you... it just... is.

Looks like a torpedo towing a U-Haul Trailer.

 

[BigMacDaddy]

I usually have used some more esoteric programs to measure rockets, convert images to SVG files so I can import into 3D design packages, etc... However, today I realized that I can use Powerpoint to check how my model matches a prototype since it is really easy to make images partially transparent to make an overlay.

 

[BigMacDaddy]

Ok, I finally had time to make the sustainer portion -- check out how hidden that retainer cap is

I am loving ABS glue to assemble these mostly 3D printed models. Do you all think that ABS glue will help glue plywood or balsa to plastic? I wonder if it would soak into the grain at all. Maybe for internal fillets?



I am going to make the booster now - let the weirdness begin!

 

[lakeroadster]

Ok, I finally had time to make the sustainer portion -- check out how hidden that retainer cap is

I am loving ABS glue to assemble these mostly 3D printed models. Do you all think that ABS glue will help glue plywood or balsa to plastic? I wonder if it would soak into the grain at all. Maybe for internal fillets?

View attachment 521669

I am going to make the booster now - let the weirdness begin!

That looks great!

The ABS to wood joint would have a better chance of being successful if you drilled a series of small holes through the fins, thus allowing the glue to fill the holes, the finished product will be like small glue "dowels" through the wood, attached to the glue fillets.

Also, roughing up the surface to be glued with sandpaper (80-100 grit) helps to give the surface a "tooth" for the glue to hold on to.

 

[BigMacDaddy]

Ok, scrapping the BT-5 cardboard tubes in the cluster booster. When I printed the parts with cut-outs for tubes they were too flimsy and looked like a beast to build the model and cut the angles on all the cardboard tubes. Anyway, fully 3D printed part comes out nice and clean and is only 31g (still needs a few other parts) for the whole booster. New ABS is a bit more streaky than the other stuff I had (need to try drying out the rolls I bought since vacuum seal on packaging was not intact).

 

[BigMacDaddy]

That looks great!

The ABS to wood joint would have a better chance of being successful if you drilled a series of small holes through the fins, thus allowing the glue to fill the holes, the finished product will be like small glue "dowels" through the wood, attached to the glue fillets.

Also, roughing up the surface to be glued with sandpaper (80-100 grit) helps to give the surface a "tooth" for the glue to hold on to.

Thanks -- good idea and easy to do with the CNC - I can just setup a series of 2mm holes for it to drill.

I have usually just glued with CA glue and the joints are very strong (especially with tabs). I am just probably falling too much in love with the ABS glue since I have so much waste support material coming out of the printer and it is fun to brush it on the parts.

 

[neil_w]

If it's a brush-on glue, then I would presume it's the sort that works by melting the two plastic parts together, in which case I would not expect it to do *anything* on wood. However, it should be something you can test and evaluate using scrap parts.

 

[BigMacDaddy]

Very pleased with the way this came out... Quite a challenge designing this but I think it came out looking like the prototype. Just a small amount more tweaking to better stabilize sustainer to booster connection and this is ready to launch (well, also need to figure out how much weight to put in the nose). Model is 19.25" / 49cm long.

 

[kenstarr]

This is a work of art! Have you considered selling the 3D printed parts yet?
Ken

 

[BigMacDaddy]

This is a work of art! Have you considered selling the 3D printed parts yet?
Ken

Thank you Ken! I did post them here with a disclaimer that I have not flown this yet -- https://cults3d.com/en/3d-model/game/mx-570-jb-3-tiamat-model-rocket

 

[kenstarr]

That's awesome! Unfortunately I've not entered the 3D printing game yet. I've been tossing the idea around in my head lately though.

 

[aerostadt]

I would think that these models might do well in NAR Sports Scale competition depending on how well they fly.

 

[BigMacDaddy]

I would think that these models might do well in NAR Sports Scale competition depending on how well they fly.

Thanks for that -- I have never gone to those launches. I would love to work with someone on getting this model entered in the competition (can a team submit or can I be sighted as the source of the design?).

 

[aerostadt]

If you launch with a local club, you might check to see if they have a NAR Section. Sometimes a local NAR Section might hold a local competition with selected events with Sports Scale being one of the selected events chosen by the members.

 

[BigMacDaddy]

Revised booster version is done that better matches original photos and diagrams (and has a better connection to booster). I am making a version slotted for plywood fins as well as one with integrated 3D printed fins with airfoil profile like the prototype. I just printed the revised version for slotted fins and it comes in at 64.6g (software estimated 64.1g so pretty close) + plywood fins are around 12.7g. The version with the 3D printed airfoil fins is 92.67g so only adding around 15.5g with 3D printed fins (although this model will need nose weight so that equates to at least 30 grams extra in total due to match in nose).

 

[BigMacDaddy]

Ok, Finally got all the parts put together (although not glued yet) so I can see where weight and CG wind up being on final model.

Simulated this in OR with a variety of motor configurations. I think I am winding up with 3oz in nose to make this stable with all that rear 3D print weight. OR does not really handle this very well so not sure how accurate the sim is.



I was hoping to launch with a D12-0 in booster and C6 but it might be too slow off the rod. Sadly, not quite stable enough with the mini engines or E-engine in rear (without more nose weight). Although, again, all of this is premised on assumption that OR is accurate enough to model this (I had to turn the canted engine tubes into thick fins which violate some assumptions).

 

[jqavins]

Ok, I know, I'm late to the party again. So sue me.

First, that is a super cool design.

I have not setup all the motor mounts / retainers yet so could easily setup the 24mm mount so you could screw in dummy plate that would convert between 24mm and 13mm.

Motor adapters for LP stuff like this don't need to be anything more that a piece tube with CRs and a hook. Put one CR flush with the front of the tube so it's up against the larger MMT's engine block. Easy to build, easy to use, and weighs practically nothing. Also easy to keep in your range box for last minute uses.

Do you guys think that museum pieces are ever "after market" - in other words are mocked up for display or rebuilt when parts are not available? Many of the

Yes, routinely. And marked as such in the plaque, as David said, but often in the small print.

This is making me want to do something similar but simpler. Just a single stage, with a cluster of motor mounts built into the fin roots, maybe canted and maybe not

 

[Pepe Le Pew]

Excellent work BMD!!!

 

[BigMacDaddy]

Model flew so much better than I ever expected it to... D12-0 in Booster and C6-5 in Sustainer. No damage to either part despite a couple of shroud lines getting burnt.

 

[BigMacDaddy]

I would think that these models might do well in NAR Sports Scale competition depending on how well they fly.

I am not sure how much more nose weight would be needed if I 3D printed the beveled fins that look more prototypical.

 

[shockie]

Here's a Tiamat variant from 1947: