Phil,You are correct that three spokes to center the barrel are optimal. They are strongly self centering, with the least flow area loss, and least surface area skin friction.The reason why I used 20 spokes in my design is because I combined two parts. In order to print them without internal supports turned on, the spokes themselves form printer support with short bridging spans. I combined parts because that way there is no question about their alignment. Splitting the parts should enable better air flow designs, although the total reflex flow area in the above design is large, compared to many factory designs. More flow area is generally better, but it matter a lot more when flow area is a primary restriction.My suggestion is that you explore making your custom shroud ID a little larger than stock. Not just to increase its internal volume, but because persuading the air leaving the barrel muzzle to make a "u-turn", without massive turbulence restricting reflex flow is much easier if design aspects have more room.
Phil,That sounds like a big project, with potential "mission creep" making it harder to finish. The fact that you lay all the parts out in CAD should help prevent surprises.
Phil,I made a 47.2 mm OD version of V3 for you. STL attached below. Had to zip the file for GTA to accept the size:
Don't know if I am confused, but my part for you above seems longer than required Phil. So, here is a shortened version of the 47.2 mm OD part, with the barrel seat one barrel diameter long.STL attached as zip file.
Fusion360 doesn't want to delete features on an imported STL, I think there ought to be a way to do that, but it's not something I've figured out yet
Quote from: Clicky on November 05, 2022, 12:14:33 AMFusion360 doesn't want to delete features on an imported STL, I think there ought to be a way to do that, but it's not something I've figured out yetI use Solidworks. The only way I can delete features from an STL is to convert it to a part file, then cut the features off using one of the regular forming operations. In the same way, I can add features. However, often the X, Y & Z axiis are shifted on such imported parts. That can limit some operations, such as revolving a profile sketch about the bore axis. A pity, because I find that the most efficient profile generation for the parts in this thread. I would often create a new part from scratch, based on dimensions taken from an STL file. It is faster than reworking STLs, and I can more easily get the shape I want. And more easily modify it later. Starting with a STEP file is preferred to starting from an STL; but modifying them is also a lot of work. How ever, STEP files can be created and read by all 3D CAD packages. So measuring key dimensions off them is easy.