(Relatively) affordable 1:72 radial engines for backpacks?

[Evil Eye]

I work in an aircraft museum, with a small selection of models representing various aircraft (mostly donated by friends of the museum). Anyway, I was admiring them when a thought occurred to me- 1:72 radial engines, with a tiny bit of conversion, would make for excellent alternative backpacks for power armour (especially Plague Marines with their very industrial, somewhat 30s-40s inspired look).

 

The only problem is, most of the separately available engines for aircraft in that scale are finely detailed resin pieces that cost about £5 for a single engine. If you're being sensible and buying a Bristol Jupiter to upgrade a Gloster Gamecock which may be a bad example as I don't think there is a 1:72 Gamecock, sadly then that's fine as you only need one anyway, but for nerds like me that want to use them for silly grimdark toy soldiers, it's a little bit on the pricey side for equipping multiple models. For "one off" models (such as a true-scaled CSM for say a Kill Team/INQ28 force) it's fine, admittedly, but for anything more than that you risk spending more on backpacks than you do on the actual models!

 

So basically, are there any affordable sources of radial engine models (preferably in 1:72) available in good numbers and not impractical to acquire in the UK? They don't have to be especially accurate or extremely detailed for obvious reasons.

[Sword Brother Adelard]

Have you thought about using one to make a press mould?

[Evil Eye]

I have, but generally speaking I tend to avoid duplicating parts that I haven't made myself out of some bizarre ethical considerations. Also I've never actually done press molding before, so there's that...

 

But yes, that is one solution.

[Fajita Fan]

Okay, I'm totally intrigued by this idea as I love random or novel conversions.  This is absolutely an opportunity for 3d printing but finding a good model to work with might take some effort.  Are you talking something like this?
https://www.thingiverse.com/thing:331491

https://www.thingiverse.com/thing:2085491

 

 

There's a few working models on Thingiverse meant to be printed as demonstrations of how a radial works but it seems like you'd want something simple to be scaled down.

[Evil Eye]

Okay, I'm totally intrigued by this idea as I love random or novel conversions.  This is absolutely an opportunity for 3d printing but finding a good model to work with might take some effort.  Are you talking something like this?

https://www.thingiverse.com/thing:331491

https://www.thingiverse.com/thing:2085491

 

 

There's a few working models on Thingiverse meant to be printed as demonstrations of how a radial works but it seems like you'd want something simple to be scaled down.

Sort of, those are obviously much too big but that is certainly the kind of engine I had in mind. I was thinking something like this, albeit it doesn't need to be ultra-detailed. This would be perfect for a one-off model mind you.

[Fajita Fan]

Well you scale it down.  I don't go back to work till Monday but I'll give it a shot and see what it looks like.  Are you talking in place of the backpack entirely or glued to a backpack?  No rounded vents on top or exhausts coming out the middle?  

[Fajita Fan]

Something like this?  The radial engine can be scaled and moved around, I cut the normal vents of someone's model of a SM powerpack and added some simple industrial looking exhausts.  

https://www.tinkercad.com/things/2Ja6WgeRWYb

[Evil Eye]

I was thinking of in place of a backpack, maybe with a few extra bitz grafted on to help with mounting and "grimdarking it up" a bit. But For the most part, in place of the normal backpacks.

 

That design you made is rather excellent though!

Edited July 19, 2019 by Evil Eye

[Fajita Fan]

The file is public, just make a Tinkercad account and start playing with it.  3d printing is really the way to get niche parts like this done and I'm totally on board with this for an inquisitor.  I'll keep playing with it too.

Edited July 20, 2019 by Fajita Fan

[Fajita Fan]

I made it bigger, added a turbopump with a single exhaust, and a couple of orange cylinders to be painted as dials.  The top is made in a way that it hopefully prints easily on a standard FDM printer.  I need to find a power armor inquisitor to mess with and I'll get one printed this week to see how it looks, this was just a few minutes of effort.

 

Next to it is a powerpack I found on Thingiverse for scale, not for printing.  The footprint is 20mm end to end, dunno how that will come out. 

 

https://www.tinkercad.com/things/kzHl0z80syf

Edited July 20, 2019 by Fajita Fan

[Evil Eye]

That's really cool and more or less exactly what I had in mind.

[Fajita Fan]

I'll clean it up during the week as I see how it prints.  

[Fajita Fan]

First try didn't print well, the fins on the heatsinks of the cylinder walls are just too tiny for the slicer and my extruder tip to handle at 17mm across and using .05mm layer heights.  I'm going to just make a simple radial cylinder unless I can find something on V twin motorcycle engine that I can pull apart.  After that it's a simple matter of attaching them to a pentagon, hexagon, septagon (sp?), octagon depending on how many cylinder we want this to have.  How many were you thinking?  I think 6 looks right and has fewer travel moves for the print head to handle.  I also really want some steampunk-esque exhaust pipes and gauges on there so the center crankcase of the engine may be bigger and the cylinder themselves shorter to cram more detail on the top.

 

Thoughts?

[Evil Eye]

I was thinking of 7 cylinders (as I had these in mind for Plague Marines, sacred numerology and all). I do like the idea of a steam/dieselpunk exhaust too, and I wouldn't mind futzing with the overall shape of the thing for the sake of 40King it up a bit.

[Fajita Fan]

Ah, 7 would be 51.4 degrees around the center so I can modify it.  I'm keeping the cylinder head and heat exchanger fins VERY simple unless you know someone with a liquid resin printer like an Anycubic Photon.  I'll keep working on this and try printing again along with some modified titan guns for Titanicus.