Wanted: P-51 Propeller info, for 3D Printed Replica. Mounted to Packard Merlin Engine.

[rrmerlin60]

Hello All;

I just joined, but have been watching this forum for a while. I am almost done creating the CAD models for a Mustang 24D50 propeller. Most parts are quite a challenge, but I feel that I'm doing OK. The blades are really hard to loft smoothly.

The purpose of doing the CAD model, is so that I can 3D print the propeller, and the complete hub, although the 4 blades will be clipped. The propeller, once assembled, will be mounted onto my Packard Merlin -9 engine. It's not a complete engine, and has many 3D printed parts as well. It will never actually run.

I would like to have any good photos I can of the propeller hub parts or blades. They are surprisingly scarce on the web. Again, it's specifically the 24D50 propeller, with paddle blades (not cuffed). Anyone have decent pics of internal parts ?

If anyone has an interest in seeing what I'm doing, please visit my Flickr page. By the way, I am not selling anything, in case you're curious. I just do this as a guilty pleasure. If you look under "Tom's Merlin Parts" all the white items are printed Nylon parts, full size. It's taken me years to get to this point. The other metal parts are real.

Here is the link; rrmerlin60's albums | Flickr

Thanks for any photos you might have. Cheers, Tom.

 

[Dash119]

Tom,

Welcome to the forum from California. Unfortunately I can't help you with any pictures or diagrams, but I must say that is one hell of a guilty pleasure...

Good luck.

 

[Michael Hope]

Which blade model do you want the one with the fully round tips, or the ones with the squared off blades with 4 inch radius on the tips. I my be able to give you some of the info you need, if internal part schematics scanned from the propeller O/H manual, which is copy righted material, so I do not want to give large sections publicly.

 

[rrmerlin60]

Hello Michael Hope.

Thanks for replying. Ideally, I'd like the paddle blades that are squared off with a radius at the tips (4 inches ? I'll assume you're right. I'll have to tweak my model. I set mine at 5 inch diameter). Do you have any pics of the root end, or the pitch change gear segment ? Or any hub internals ?

See picture.

Cheers and thanks again, Tom.

 

[rrmerlin60]

Oh, I paid better attention to your text just now. I have access to some manuals, from the website Aircorpslibrary.com. I am not affiliated with this, nor do I publicly endorse this site. I will say, that I get real value out of the site, which has some Hamilton Standard manuals. Even better, it has excellent dimensioned drawings of Packard Merlin parts. These are hard to find, so I love wading through the hundreds or thousands of drawings they have for this engine, plus many others. Again, not an official endorsement, just a confession that in my opinion, this is an excellent, low cost resource.

So if you have propeller manuals, I am guessing that images of each part is very small, with no dimensions, etc. Am I wrong ?

Thanks, Tom.

 

[Michael Hope]

Hello Michael Hope.

Thanks for replying. Ideally, I'd like the paddle blades that are squared off with a radius at the tips (4 inches ? I'll assume you're right. I'll have to tweak my model. I set mine at 5 inch diameter). Do you have any pics of the root end, or the pitch change gear segment ? Or any hub internals ?

See picture.

Cheers and thanks again, Tom.

Here are the pages that I can access, one is the difference in data between the 23E50 propeller and the 24D50 series, note the cams shown are for the full feathering propeller, i.e. P-82, not the straight slope cams as the P-51 used. The other is a sheet with the blade dimensions, and a page for making the templates for checking the angles, but it gives the blade width plus the curvature of the leading edge.

 

[rrmerlin60]

Hi Michael;

Thanks for this. It'll take me a while to grasp all the data in your second attachment. But much appreciated.

Tom.

 

[MiTasol]

One of the Aircorps Library manuals has all the exact dimensions of the blades - look for blade repair or similar title

There may also be hub, dome and spider dimensions in repair manuals and in the overhaul manuals where they usually list dimensional tolerances for the parts. These will only show significant dimensions but you can scale the drawings from there. Your software will probably show when items interfere with each other.

 

[fshort]

Hi Tom:

Your parts are fabulous! The amount of modeling you've done is just staggering...

I didn't know how much work the research is on a project like this - I thought the parts-building would be the hard part!

Please post your progress.

Regards,
James

 

[Jim MacDonald]

Wow, what an awesome project. The amount of work that you've put into it and the amount of detail is incredible. Please keep us posted as you continue your work.

Mac

 

[rrmerlin60]

James and Jim (or Mac, I suspect you prefer),

Thanks. It is a lot of work, but I really get serious enjoyment out of it. My workplace also benefits, although, they'd never understand it. My voluntary practice of reverse-engineering has made me much better at my job. When I'm motivated to succeed at creating a model, I work harder at it.

Cheers, Tom.

 

[rrmerlin60]

Mitasol;

I'll ask Ester at Aircorps about any dimensioned propeller parts drawings. I didn't see any when I looked through, but I admit that I didn't closely scour every page. Thanks for the idea. Aircorpslibrary is an outstanding resource.

Tom.

 

[Jim MacDonald]

Tom,

Thanks for your reply. I sent this link to my Nephew. He is very much into 3D printing and was blown away by your work. He'd like to know what printer you are using? Your reply also piqued my curiosity on what you do for a living. I'm looking forward to see more of your work. I'm currently trying to get a handle on Solidworks to help me with building a Zero model (definitely not 1:1 scale).

Mac

 

[MiTasol]

Aluminum Blade Overhaul Manual for Hamilton Standard Propellers | AirCorps Library
This manual has blade dimensions - see below page at random

random page from Hamilton Standard Blade Repair Manual | AirCorps Library

Random page from Hamilton Standard Multiple Blade Design Dimensions and Service Bulletins | AirCorps Library

 

[rrmerlin60]

Hi Mac;

I use a 3D Systems HiQ, Selective Laser Sintering station (SLS). It's an industrial printer, not what you'd find in a kid's bedroom. Although, any reliable printer is an excellent start. Your nephew will learn a lot about file creation or repair, maybe reverse-engineering, which is a challenge, but for me, very rewarding.

I work at Canada's National Research Council. I was with the Aerospace department for 10 years, and then suddenly transferred overnight, as government organizations will do, to the main machine shop. I thought this was a horrible demotion, but I wouldn't go back if you doubled my salary. Suddenly, I'm put in charge of a good 3D printer, and I've been the sole user of it for almost 10 years. I create parts for research projects of all types, mostly wind tunnel models, so my work is running the printer, but mostly designing and prepping parts to print. And as I mentioned, my interest in rev-enging Merlin parts has forced me to get to know the software better.

I don't use Solidworks, but a few years ago, that became the standard design software for our Design Office, replacing Pro-E, which I've also never used. I am self-taught in Rhino 3D software, which I found fairly intuitive and enjoyable. Self-taught means I might know 2% of the total software package, which means, I can still do a lot. Others laugh at me, but I'm glad I fit into an "experimental" group that has carte-blanche on tools that we use, such as Rhino, ancient CorelDraw and Corel Photopaint (still very useful), Spaceclaim, the main reverse-engineering software, and Magics, the printing file prep software.

So that's the Readers' Digest story of me. I had hoped to get my Merlin running, but I'm missing so many real parts and internals, that I will settle for sprucing it up to appear complete. My goal is to fool a Merlin expert. Still years to go on that, but most of the big parts are now done, and I consider a propeller and working hub as icing on the cake.

Good to talk to you, and best of luck on the Zero project. Please keep the forum posted on your progress.

Tom.

 

[rrmerlin60]

Thanks for the data sheets, MiTasol. I will try to digest what they mean at some point.

Cheers, Tom.

 

[Jim MacDonald]

Hi Tom,

Thanks for the info. Sounds like you have a real interesting job and are in a good win-win situation to boot. Your job helps you with your hobby and your hobby has improved your abilities at work.

If I can teach myself 1% of Solidworks I'll be doing pretty good. Actually though, Youtube is a great resource with many excellent Solidworks tutorials. So I might actually get to 2% myself.

Take care,

Mac

 

[Bigmerle]

RRMerlin60,
Interested to know where you came up with a -9 Merlin? Used in the H model Mustang and don't know where else. Just curious.

 

[rrmerlin60]

Well, that's a good point. I bought a -9 crankcase from California. So I call it a dash 9. No doubt, the total collection is a mish mash of Merlin parts, of different marks. But I'm calling it a dash9. I guess I'm not a purist.

 

[Tom Fey]

Ironically, the P-51H used the Aeroproducts A542 propeller exclusively.