Been doing a CAD model of the Merlin Engine just for fun
Sat Dec 05, 2020 4:34 am
I've been working on this for a couple of years now but I haven't had a lot of time to focus on it until recently so I thought I'd finally share it.
This is a CAD model of the Merlin engine, specifically the Packard V-1650-7 as was flown in the P-51 Mustang. It is modeled and rendered in
SolidWorks using blueprints from Aircorps Library. I'm currently working on the upper crankcase assembly, I've been working on the main
casting for the better part of a year now. I have more time to focus on it now so finishing it up should go quicker.
The hardest part was filleting. I swear to ... heaven ... that I spent at least 20 hours or more doing filleting on this thing. Filleting, in CAD, is to
add rounds to all the sharp inside and outside corners. On a casting it's generally the last thing you do so I saved it all up till the end. That
was a fun few days where it was really hard to motivate myself to open the model. I've done three other top level assemblies that I will post
about shortly. If you want a sneak peak of the model and can open various types of CAD files, I've posted the ssolidworks, parasolid, iges, and
step files on my grabcad page. If I did my signature right you can find the link down there.
I've also picked up my blog again where I will be posting the progress as it happens, you can find that link down below, too, if you care to follow
along at all. I'll keep posting the progress in here as well.
Thanks for looking and I'll post the other assemblies in the morning.
Edit: sorry for the poorly sized images, I'll see if I can fix that somehow.
This is a CAD model of the Merlin engine, specifically the Packard V-1650-7 as was flown in the P-51 Mustang. It is modeled and rendered in
SolidWorks using blueprints from Aircorps Library. I'm currently working on the upper crankcase assembly, I've been working on the main
casting for the better part of a year now. I have more time to focus on it now so finishing it up should go quicker.
The hardest part was filleting. I swear to ... heaven ... that I spent at least 20 hours or more doing filleting on this thing. Filleting, in CAD, is to
add rounds to all the sharp inside and outside corners. On a casting it's generally the last thing you do so I saved it all up till the end. That
was a fun few days where it was really hard to motivate myself to open the model. I've done three other top level assemblies that I will post
about shortly. If you want a sneak peak of the model and can open various types of CAD files, I've posted the ssolidworks, parasolid, iges, and
step files on my grabcad page. If I did my signature right you can find the link down there.
I've also picked up my blog again where I will be posting the progress as it happens, you can find that link down below, too, if you care to follow
along at all. I'll keep posting the progress in here as well.
Thanks for looking and I'll post the other assemblies in the morning.
Edit: sorry for the poorly sized images, I'll see if I can fix that somehow.
Re: Been doing a CAD model of the Merlin Engine just for fun
Sat Dec 05, 2020 5:49 am
Fantastic 
Love the rendered images as well.
As someone who has spent over 20 years involved with 3D CAD/BIM (but in a different discipline) I can really appreciate the work involved in doing this.
Love the rendered images as well.
As someone who has spent over 20 years involved with 3D CAD/BIM (but in a different discipline) I can really appreciate the work involved in doing this.
Re: Been doing a CAD model of the Merlin Engine just for fun
Sat Dec 05, 2020 5:54 am
How bigs your 3D printer?
I did a rough Db605 in ProDesktop 2000ic.That was fun.
I did a rough Db605 in ProDesktop 2000ic.That was fun.
Re: Been doing a CAD model of the Merlin Engine just for fun
Sat Dec 05, 2020 6:42 am
Nice work. I would pay good money for a quality engine series that was 3D printed in a manageable scale and could be assembled into display models. Metal hardware would be a bonus or a good parts list to order and finish construction.
Re: Been doing a CAD model of the Merlin Engine just for fun
Sat Dec 05, 2020 7:01 am
Great work! I've just started teaching myself Solidworks to help with a Zero model, so I will be following your blog for sure.
Mac
Mac
Re: Been doing a CAD model of the Merlin Engine just for fun
Sat Dec 05, 2020 12:26 pm
Is this just a hobby or are you hoping to turn this into a profit/business ?
Phil
Phil
Re: Been doing a CAD model of the Merlin Engine just for fun
Sat Dec 05, 2020 1:38 pm
Thanks for the response, guys. I appreciate it.
Firebird, you must know my pain with the fillets then.
Spitty and Dora, I have a Creality CR-10S but I doubt it would be up to the task with the level of details involved here. My buddy is getting a resin based one next year, maybe then.
Hey Jim, how are things going? I'm the guy who was going to borrow your corsair drawings but then ended up working at Aircorps. I think I still have a portable hard drive you sent me. You finally started learning 3D modeling yourself, huh? Did you get the EAA deal? I have a LOT more experience with modeling airframes now so ask me anything you need help with, I have some really good methods for modeling airframes in SolidWorks. Send me an email at my gmail account using this username, let's catch up.
Just for fun, Phil, and maybe a little bit of marketing now that I am no longer gainfully employed at Aircorps (the business slump has hit the industry hard). Well, maybe I should say 100% for fun but I am not passing up on the opportunity to use it as a marketing ploy. I don't have an intended output, I just really love doing fun and challenging projects in CAD. I wouldn't mind monetizing it once it's done if that were an option, but I kinda doubt anyone is paying good money for this kinda thing.
Firebird, you must know my pain with the fillets then.
Spitty and Dora, I have a Creality CR-10S but I doubt it would be up to the task with the level of details involved here. My buddy is getting a resin based one next year, maybe then.
Hey Jim, how are things going? I'm the guy who was going to borrow your corsair drawings but then ended up working at Aircorps. I think I still have a portable hard drive you sent me. You finally started learning 3D modeling yourself, huh? Did you get the EAA deal? I have a LOT more experience with modeling airframes now so ask me anything you need help with, I have some really good methods for modeling airframes in SolidWorks. Send me an email at my gmail account using this username, let's catch up.
Just for fun, Phil, and maybe a little bit of marketing now that I am no longer gainfully employed at Aircorps (the business slump has hit the industry hard). Well, maybe I should say 100% for fun but I am not passing up on the opportunity to use it as a marketing ploy. I don't have an intended output, I just really love doing fun and challenging projects in CAD. I wouldn't mind monetizing it once it's done if that were an option, but I kinda doubt anyone is paying good money for this kinda thing.
Re: Been doing a CAD model of the Merlin Engine just for fun
Sat Dec 05, 2020 2:07 pm
I've messed with Autocad and know that this is no small job. Great work!
Re: Been doing a CAD model of the Merlin Engine just for fun
Sat Dec 05, 2020 5:06 pm
Thanks Scott, it's appreciated.
Here's the first and second assemblies I modeled. The first is the Starter, I did it back in 2018. It was pretty straightforward, but those of you who know SolidWorks know that it doesn't do gears well. There was a learning curve but the gears in this assembly are accurate and machine quality. I wasn't able to do or approximate the windings, not because they were too hard or because I didn't want to, but because they were one of the very few drawings that are not in the blueprint set. Still I got everything else in there done.
The next assembly I started in early 2019, it's called the starter engagement mechanism. It's a clutch mechanism that acts in place of a modern solenoid to cause the gears to mesh while the engine is starting but then declutch once it's above a certain speed. You can see the clutch pack in the cross section view.
And here's the last, it's an intermediate drive shaft that takes power from the crankshaft/supercharger input shaft and drives the pair of magnetos that are mounted to the wheelcase. The wheelcase is the big casting behind the crankcase that supports the supercharger assembly and air intake.
Here's the first and second assemblies I modeled. The first is the Starter, I did it back in 2018. It was pretty straightforward, but those of you who know SolidWorks know that it doesn't do gears well. There was a learning curve but the gears in this assembly are accurate and machine quality. I wasn't able to do or approximate the windings, not because they were too hard or because I didn't want to, but because they were one of the very few drawings that are not in the blueprint set. Still I got everything else in there done.
The next assembly I started in early 2019, it's called the starter engagement mechanism. It's a clutch mechanism that acts in place of a modern solenoid to cause the gears to mesh while the engine is starting but then declutch once it's above a certain speed. You can see the clutch pack in the cross section view.
And here's the last, it's an intermediate drive shaft that takes power from the crankshaft/supercharger input shaft and drives the pair of magnetos that are mounted to the wheelcase. The wheelcase is the big casting behind the crankcase that supports the supercharger assembly and air intake.
Re: Been doing a CAD model of the Merlin Engine just for fun
Sat Dec 05, 2020 5:57 pm
Nice job, bit the OCD in me just wants to bend that cotter pin over... 
Phil
Phil
Re: Been doing a CAD model of the Merlin Engine just for fun
Sat Dec 05, 2020 6:15 pm
Trust me Phil, there was a debate in my head, but I ended up doing it similar to the drawing rather than what I'm used to doing which would be like on car wheel bearings and split the legs left and right.
Re: Been doing a CAD model of the Merlin Engine just for fun
Sat Dec 05, 2020 8:28 pm
Wow you guys are talented. As technology progresses we will be able to re make anything for a relatively cost effective price.
Re: Been doing a CAD model of the Merlin Engine just for fun
Sat Dec 05, 2020 8:47 pm
I think at some point single material "replicators" like in Star Trek will be a thing. 3D printing taken to it's natural conclusion, you'll be able to make something from whatever material you are working in and it'll just be a finished part that will be useable in any application. I am hoping that means people like me who make the models will be in high demand for a long time to come.
Re: Been doing a CAD model of the Merlin Engine just for fun
Sun Dec 06, 2020 4:30 am
A few years ago someone was finishing off his Merlin with 3D printed parts..
https://www.flickr.com/photos/130143587@N02/albums/72157650467086187
https://www.flickr.com/photos/130143587@N02/albums/72157650467086187
Re: Been doing a CAD model of the Merlin Engine just for fun
Sun Dec 06, 2020 7:24 am
Yeah, that's Tom Kay, I was introduced to him through work a while back and he was kind enough to share a 3D scan he had taken of his crankcase and wheel house assemblies. I intend to make those part of another blog post soon. He's a great guy, he's got some Merlin parts in his basement and is 3D printing stuff like the heads and stuff in order to finish it off as a display model. You know, just to have a Merlin in your parlor!