Hartzell Hub and Blade Proxies

[TParker]

In an effort to make things easier where I can, I've developed a set of 3D printed files that can be used to make proxies for Hartzell hubs and blades. I think this would allow the actual bulkhead to be mocked up to the cowling and also make spinner cutouts easier. I've got hubs for the most common Hartzell props sold through Vans, and blade stubs for the 7497 and 8068, the most common blades where builders are using the kit spinner. The only critical hardware is the spinner mounting kit (spacers and washers) where you need to ensure the same dimensions between the real hardware and the stand ins or use the real spacers/washers. Otherwise, whatever hardware is handy suffices.

Here's an example installation just starting:

I've also made additional parts that could help builders complete their spinner by providing replica blades, with pitch adjustment, and location for the forward. Here's a complete mockup for one side:

Might be easier to build the spinner if you use 2x the blade parts rather than one side at a time.

The pitch adjustment keys on a curved slot with the angles predefined to match what we ship, plus some margin.

You can see this spinner cutout needs some tweaking.

After the first mockup, I made lightweight versions to use less material:

Compared to an actual prop:

Print settings are left to the user, I generally printed this in PETG with 3 or 4 walls and 15% infill. They're designed to be printed without supports, and mine were successful that way.

I've written a preliminary guide of instructions, eventually it'll end up being absorbed into Manual 193, Volume 3. The guide and files (in both STL and 3MF) are available for download here, until we find a more permanent home for them.

If you use them and run into issues, or have ideas for improvement, please let me know.

 

[graywoodworking]

That's very nice. I wish I had that two years ago!

 

[Richard Connell]

That’s such a good solution to this problem.
Bravo.
I still have an unairworthy compact hub sitting in my roof from almost 20y ago that I used. That worked too but this is much better. Especially the blade roots.

 

[DeltaRomeo]

Trevor, thank you for posting this! I took the liberty of making this a sticky in the 3-D printing sub forum. Thank you again!

 

[kiwipete]

Brilliant, I just wish these were available when I did mine.

 

[Estevanb]

In an effort to make things easier where I can, I've developed a set of 3D printed files that can be used to make proxies for Hartzell hubs and blades. I think this would allow the actual bulkhead to be mocked up to the cowling and also make spinner cutouts easier. I've got hubs for the most common Hartzell props sold through Vans, and blade stubs for the 7497 and 8068, the most common blades where builders are using the kit spinner. The only critical hardware is the spinner mounting kit (spacers and washers) where you need to ensure the same dimensions between the real hardware and the stand ins or use the real spacers/washers. Otherwise, whatever hardware is handy suffices.

Here's an example installation just starting:
View attachment 57302
I've also made additional parts that could help builders complete their spinner by providing replica blades, with pitch adjustment, and location for the forward. Here's a complete mockup for one side:
View attachment 57305
Might be easier to build the spinner if you use 2x the blade parts rather than one side at a time.

The pitch adjustment keys on a curved slot with the angles predefined to match what we ship, plus some margin.
View attachment 57306View attachment 57307
You can see this spinner cutout needs some tweaking.

After the first mockup, I made lightweight versions to use less material:
View attachment 57308

Compared to an actual prop:
View attachment 57309

Print settings are left to the user, I generally printed this in PETG with 3 or 4 walls and 15% infill. They're designed to be printed without supports, and mine were successful that way.

I've written a preliminary guide of instructions, eventually it'll end up being absorbed into Manual 193, Volume 3. The guide and files (in both STL and 3MF) are available for download here, until we find a more permanent home for them.

If you use them and run into issues, or have ideas for improvement, please let me know.

Great job!

Thanks for sharing this with the community!

 

[georgemohr]

Looks great!!! We used Vans method of building standoffs, and man let me tell you it was a scary moment when be brought the completed cowl up to the mounted prop for the first time

 

[jandetlefsen]

and blade stubs for the 7497 and 8068

Hello, this is amazing. Just started working on my spinner. I'm not too familiar with the prop series naming rules. I got a 3 blade prop with blade model 76C03-2X2. Can i use any of those stubs?

 

[TParker]

Hello, this is amazing. Just started working on my spinner. I'm not too familiar with the prop series naming rules. I got a 3 blade prop with blade model 76C03-2X2. Can i use any of those stubs?

That's a different blade, so you'll need the stub specific to it. It also will need a different blade adapter because it's a different propeller type. I didn't make those parts yet since most people don't build their own spinner for the three blade props. I'll try to make and upload the parts you need next week.

There's a prop configuration section in Manual 193, Volume 2 (on our website) that helps explain the propeller model naming. The instructions for these 3D printed parts also reference that manual.

 

[jandetlefsen]

That's a different blade, so you'll need the stub specific to it. It also will need a different blade adapter because it's a different propeller type. I didn't make those parts yet since most people don't build their own spinner for the three blade props. I'll try to make and upload the parts you need next week.

There's a prop configuration section in Manual 193, Volume 2 (on our website) that helps explain the propeller model naming. The instructions for these 3D printed parts also reference that manual.

That would be amazing and make the process so much easier. Thank you. Will have a look at that PDF again.

 

[TParker]

In working on some new parts, I found an error in the Compact blade adapter part; I transposed two digits on a dimension for it which resulted in the rotation axis being 0.090" too close to the flange. Revised part files (rev1) have been added to the folder, please update your parts. Sorry about that.

 

[TParker]

That would be amazing and make the process so much easier. Thank you. Will have a look at that PDF again.

I've created and added the files you should need to the download folder.
The full set of files you need should be:

1. 3C1_R430_SpinnerMountFixture_LWT_rev0
2. 76C03_BladeStub_IDS-3632_Rev0
3. 3C1_RaptorBladeAdapter_Rev0
4. 3C1_CylinderPost_2Pc_PartA_Rev0
5. 3C1_CylinderPost_2Pc_PartB_Rev0
6. CylinderPostPeg_Rev0 (optional)

Please let me know if you run into any issues.

 

[jandetlefsen]

This is great, thank you so much!

 

[jandetlefsen]

Found a minor bug in your design. Filename 3C1_R430_SpinnerMountFixture_LWT_rev0. One of the fixture to engine holes doesn't have a flange, see screenshot from my slicer. Unless that's intended.

 

[Richard Connell]

Found a minor bug in your design. Filename 3C1_R430_SpinnerMountFixture_LWT_rev0. One of the fixture to engine holes doesn't have a flange, see screenshot from my slicer. Unless that's intended.

View attachment 60341

Intentional. For indexing the hub on the crank/flywheel.

 

[jandetlefsen]

Here is how i've been using it.

First off a tip: Check your prints for dimensions after printing. I had some shrinkage between base and the spinner forward flange but that was easy to compensate with a printed shim.

My job for now is to cut out the spinner for my 3 blade prop with the help of those parts. I found out right away that my spinner front plate is too big. So i designed a new one and did a test 3D print before having it machined. Having all those mockup parts on your desk helped immensely. The new front plate did fit on first try.

I've done a partial layup of the spinner perviously as a method to create a cutout template. So i used a piece of that and glassed it to an piece of angled aluminum sheet that fits right under the screws. That way i can use the 3D printed prop studs and then transfer it to each of the 3 cutouts onto the actual spinner. Since the spinner is carbon fibre i rather prep more and cut less. I used slots so it's very easy to take off, work on the cutouts and then mount them back with precision every time. That makes it fun actually.

Started with a line laser to mark the middle of the prop stub and cut a round hole. Once the round piece of the adapter fit through the hole i was able to stick on the blade stub on and copy the outlines on the glassfibre. From there i was easy to widen the gap to what i wanted while turning the blade stub was limited in angle by the screw and the slot in the 3D print.

To be continued but wanted to share and say thank for the 3D print files that make it so much easier.