Replica Merlin Head Parts 3D Printed. Awaiting final touches….

Hello Group;

Sept 27 was my last post, so the months really tick by. That’s how long it has taken to print 12 parts of the left Merlin head. And a few valve sets.

The head is around 42 inches long, so no chance of printing it in one shot. At best, if I owned the printer, it would be 3 large parts. Doing it in 12 parts made it easier to add parts of the head into other project builds, when there was spare room. Fitting in a few valves and springs, here and there, is easy.

I have a lot of work to do to complete this head. I’ll meticulously clean each tongue-and-groove glue joint, and then glue all the parts. I’ll have to create some alignment jig to make sure all the parts are nice and straight as the glue cures. Then I’ll do some “bondo” work at each joint to conceal each crevice that is visible, so that it looks like it was made in 1 piece.

I’ll post a few more pics of the individual 12 pieces, for those who are interested, and some decent closeups. Here is the address to my Flickr site;

https://www.flickr.com/photos/130143587@N02/albums/with/72157650467086187

More later, Tom.

SabreJet, Tony (or is it Darryl?), you guys are awesome. Thanks for this early digging. It appears that some of the details that you have found are lining up reasonably well with my father’s recollections. He mentioned that the appendicitis came first, he thinks 1915 or early 1916. He told me that the Manchester Regiment troops were literally formed into ranks on the dock when he became incapacitated enough that they had to take him away to the hospital. Your service number, 125931 also aligns with what my dad wrote to me yesterday, so you’ve got the right TC Kay.

Thanks again, Tom.

Hi Brian;

Thanks for the reply, and the link to that website. My Grandfather’s name was same as mine, Thomas C. Kay, except that my “C” is for Charles, his was for “Clampitt” after his mother’s maiden name. Thomas Clampitt Kay.

(I added a second t to his middle name, as corrected by my dad)

3D Scanned Merlin Parts. A look at the Process

Hi;

Just wanted to share a bit about the process of how some replica Merlin parts are made, at least by me. I took the 3D scanner from work and visited Vintage Wings in Gatineau Quebec last Saturday, and came away with some very usable scan data. My goal was to capture as many of the parts that I don’t have as I could, with hopes of reverse engineering them into a clean CAD model. I would then take the models, cut them into printable sized pieces, print, glue them into one part, paint them, then mount them onto my ongoing project.

I need quite a few parts, such as the aftercooler box, valve covers, and many others. Scanning took longer than I’d hoped, so I limited my attention to those items. It’s always better to have any item to be scanned, sitting on a bench in front of you, rather than scanning it in-situ. This is because you can roll the item into several orientations to effectively scan all surfaces and capture as much near-watertight data as possible. Scanning the aftercooler box while it’s on the Merlin was useful, but not perfect, as you can see from the pictures below. The partial, sort of shredded looking box is actually a merge of 3 scans, and unfortunately I’m still missing the entire bottom surface, and most of the front. Oh well, it’s a decent start.

The valve covers worked out better. They are flat on the bottom, and even mounted on the Merlin, stick out prominently enough that I captured the entire upper surface (almost). That way, I don’t have to guess at reconstructing much of the scan data to make it watertight and usable for reverse engineering or 3D printing. The grid-like things and the goofy bumps that are visible on the top surface of the valve cover, are both parts of the net that I had to drape over the valve cover as I scanned it. This net has a grid-like pattern of reflective targets which the scanner must see in order to acquire its scan data. There are many different scanners, but our hand held scanner relies on this 3D grid of “stepping stones” to understand what it’s seeing.

After scanning, I can “switch off” the target dots, and just work on cleaning up the ugly, rough scan data. The 2 valve cover images are both ends of the left valve cover, and the first thing that comes to mind is, “Where the hell do I start?” The extra peripheral junk is cleaned away. Then the 2 clean pieces that I want are carefully aligned and merged into one semi-ugly scanned model. From there, it’s a case of removing bumps, fixing holes, and eventually getting to the point where it looks finished, like the green valve cover. Since it’s an stl file (called STereo Lithography) I can actually print the item right from this format, or I can choose to use a reverse engineering software to make it into a really clean, crisp model. The softwares I use to reverse engineer the stl scan data, are Geomagic, and the user-friendly SpaceClaim. Sometimes good old Rhino, although it’s not really a proper rev-eng tool. Rhino is usually good for simpler parts, where I import the 3D scan data as an actual “part” and then build shapes that mimic the scan model. I weld those parts together until I have a big, often complex assembly. That’s how I modeled the entire V-Drive, cylinder skirt and head. Only now am I starting to use proper reverse engineering software to make solid models from scan data, and it’s been incredibly helpful. The advantage of having good software is massive time savings, in preparing the scan data to become printable 3D models. The cylinder head has taken well over a year, and is not quite ready to print. Still more details to add. The valve cover, admittedly much simpler, has taken 2 days of spare time to go from hideous to almost printable. I’ll add the Rolls-Royce label, because even P-51 owners with Packard Merlins strive to find the valve covers that say “Rolls-Royce.” I would !

So, bored with details? Have a look at the images and enjoy. Cheers from Canuckville, Tom.

Merlin Restoration. Some recent progress.

Alright gents,

I’m getting excited because I’m getting closer to 3D print time. I have the CAD model of the left cylinder head almost complete. It’s taken months to get to this point, although this is what I call spare time, not full time. It really helps that I was able to scan the right head, mirror image it and use it as a visual reference while CAD modeling the left head. There are differences between the left-right heads, but not too many.

Some of you eagle-eyed Merlin gurus will spot some errors or things not yet complete. The biggest change to come, are a bunch of blind holes that will be printed, tapped, and then accept studs which hold the head to the cylinder skirt, or the valve cover to the head, that sort of thing. I also have to hollow out this solid model, but with modern software, that’s not too hard. I want the inside coolant passages to look like the real thing.

So, Chevy Orange, Royal Purple, or red with black accessories? Still can’t decide.