Today I have some issues regarding the geometry of this part I want to built as accurate as possible, it’s a Hamilton Standard Hydromatic Propeller Hub ( the part that holds the blades together and allow the pitch movements )
From my basic mechanical understanding, it consists of four cylinders at 90° ( one for each blade ) that sinks into the main cylinder, the one that is bolted onto the engine shaft.
But I can’t figure out what’s really happening during that merge, cause the intersection lines I got when merging these geometries doesn’t resemble at all what I see on the real one.
I’m not a expert in Blender, just a medium/advanced user, but most of the time I’m stuck with geometry understanding problem ( how it’s built IRL ) rather than software " how to " related stuff.
Do you have any directions, or tips to achieve that ?
Here are some shots of the final result I want to achieve, and where I’m currently stuck out.
I wonder whether I should directly start modeling that in a CAD software then exporting it to Blender, those usually are easier to handle mechanical parts such this than Blender.
Well, I will also have to model this Hamilton Standard hub, when I will work on the SBD-4 or one of the later Dauntless versions :yes:.
Your approach seems correct, the cross-section on the forward part of the hub can be OK - just take into account two elements your model is still missing: the thick flange in the middle of this hub, and relatively large fillets around every edge (I used your drawing to show what I mean):
The intersection curve in the rear part: from your photos it seems that there is an additional, thicker body in the middle - something that resembles a cylinder of somewhat larger diameter, but less regular (see the picture above).
I suggest to experiment with these basic elements using Boolean modifier (in the Union mode). You can also create fillets them using after Boolean another modifier (Bevel, in its multi-segment mode). In this way you can quickly determine appropriate proportions of these basic bodies.
If you do not want the Boolean modifiers - you can also use this add-on to quickly find intersection edges.
BTW: did you notice that there are significant differences between the hubs on your photos?:
(Which one of these two are you modeling? I have impression that the left one is a modern version, while the right one is a original from the middle of previous century…)
To answer your question, it’s the exact same hub, just the left chromed and shiny one is the BACKPLATE of the Hub, while the right one, old rusty metal is the front part ( look at the whole complete Hub Assy, the chromed one, on my original post )
Oh, I see! So this is an evidence that there is “somewhat bigger” block (cylinder?) in the rear, as it could be deduced from the intersection edge of the smaller rear cylinder with the rest of this hub body!
I want to model BOTH 3 and 4 blade versions, but they are obviously not the same, one with three holes at 120° and 3X4 bolts ( 4 per side ) and the other with 4 holes at 90° and 3 bolts per side
You just re-used that Hartzell hub, if I would have wanted it I could have done this, but thanks for the sympathetic gesture
But no, I really need to built this one from scratch, and am currently experimenting different approaches to reach it, shouldn’t be that hard, but as Witold said, there is this strange and mystery " kinda somewhat bigger " cylinder in the middle of the hub.
Hi After some times playing around with it, it starting to take shape. Still I can’t get the same " intersection curves " shape as the real one… Mathematically, there is only one intersection between two cylinders of a given diameter, but on the real hub the intersection curve is different than the one I got here.
and can you show on pic which part seems to be off with red marker
so we know which parts are not as pic
did the last pic help a little to see 3D shape ?
but what precision are you looking for?
I mean do you want to do very close shots of it or only from far away?
I’m looking for as accuracy as possible, for close shots ( among other things ) but the also to serve as a base for a Solid Works model and eventually a CNC machined working Hub.
Anyone would have ideas for a cool way to make that flange that contains bolts and bolts housings between blades shank cylinders ?
not certain how well you can export this to a CNC which needs precision down to 1/1000 In or less
I mean blender use polygonal mesh so if you want it with high precision then it would need to be high segment value for circular things
unless the smooth is included in the export !
may be @Witold_Jaworski
has an idea on this !
PM him and ask may be!
you should open new thread in python forum and ask about that CNC export from Bl and precision
other people have use this and might be able to help on the precision thing !
also don’t forget Bl is limited to 7 digits precision !
so scale is important here !
