I figure if I’m going to discuss modifying the spinner flow guide that ya’ll might want a reminder of what the current one looks like. I’m sure you’ve seen this “lampshade” style flow guide before since it’s probably the most common, or close to it, for the ‘Hershey Kiss’ style spinner.
Here’s an inside shot as well. This flow guide is designed to mount to the prop flange on the prop extension side and then butt up against the aft side of the flywheel on the forward side.
Again, in its current stock state this “lampshade” style flow guide will not fit into the aft opening of my cowlings. To use the Catto prop spinner I need to modify the flow guide shape to be more along the line of the style Klaus Savier sells on his Lightspeed Engineering website:
Although it’s not overly visible, notice that the flow guide above does not butt up against the aft face of the flywheel, but rather curves around and free floats over the prop extension. In order to install the flow guide it clearly has to fit around the prop extension prop flange, which is normally 7″ in diameter.
I plan to reuse the aluminum mounting plate, mounting flange and nut plates from the current flow guide, and remove all but the aft 1.3″ of it. Moreover, in my design modification I need to ensure that its configuration avoids the cowlings’ aft opening edges, thus the resulting design on mine is not curved like the one above, but rather straighter.
After getting the bolt patterns dialed in and test-fitted, I then modeled up the rest of the modified prop spinner flow guide in Fusion 360 CAD:
Here’s another shot of the aft face of the flow guide with the mounting flange for the spinner and the bolt stud holes.
Finally, a look at the inside of the new, modified prop spinner flow guide.
As I discussed yesterday, since “Geeks gonna geek!” for no real damn good reason, I spent a good 2-1/2 hours recoding and re-tweaking my firmware settings because somewhere there is a momma’s-boy that apparently needs to have a sense of purpose in life by arbitrarily changing crap!!
But I finally got it. One more round of this BS and I’ll be changing my firmware from the 3D printing world’s darling, Klipper, back to something stable and boring like Marlin.
Here’s the initial part of the print: the aft face of the flow guide. I started with blue ABS but didn’t want to burn through the entire roll of it.
Although I made the mounting face only 0.05″ thick, for something this big around it took a good bit to lay down that much plastic. If you look closely at the screen below you can see at this point this thing had already been printing for 5 hours and 11 minutes, with another estimated 12-1/2 hours to go. And that’s at a speed nearly twice as fast as my other 3D printers!
About an hour after I grabbed this shot I swapped the filament out to a fresh new roll of silver ABS to ensure that the print didn’t run out of plastic in the middle of the night. Plus I didn’t want to use all my blue ABS in this one print.
A bit later in the evening I sanded the micro I had applied to the bottom inboard edges of the rudders. I also removed all the protective tape and cleaned up the surrounding glass.
Yes, definitely not good enough for the actual finish of the rudders, but good enough for what I’m doing here: just getting a decent straight fill for the tape to sit straight on….
I then taped up the bottom of the rudders and cut the associated peel ply for the upcoming layups for the winglet intersection fairing, which I had planned on doing tonight.
But I hadn’t sat down and really thought through my layup schedule from A-Z, and it was starting to get a bit later in the evening. Jess had just arrived, being sweet to come over and cook dinner, so I decided to kick this layup can down the road until tomorrow.
After a great meal with Jess, and then switching the filament over to the silver roll… and with all looking good with Max (my new 3D printer), I called it a night.