First prints of Cleaver style propellers for RC Boats.

Very exciting to receive the first test prints in WSF of these Cleaver style propellers. Turned out very nice.

The blade profile is calculated using a spreadsheet with the inputs being diameter, pitch, rake, max blade width, leading edge pitch and trailing edge cup resulting in a propeller with progressive pitch. Pure linear pitch propellers can also be made.

The data is exported as a profile for 16 radial sections and exported in xyz format (x,y,z coordinates) and then imported into DesignCAD 3D Max for lofting into a low/med poly count mesh. The model is then exported to an .obj file and imported into Blender for final modeling (addition of hub, part numbers, and the final blade count). Subsurface division is used to create a smooth lofted model.

All in all 9 slightly different propellers were printed and they turned out very nice. Thx SW for the service.

they look great - what is the size/scale of the engine, it looks huge for RC!

The engine itself is a .21 cui (3.5cc) 1-cyl running on a methanol/nitro fuel mix and it is mounted on an outboard drive unit.
In this configuration is generates around ~1hp at 28-30k rpm.
Size wise this is actually one of the smaller displacement engines but it is one of the most common

The propeller is 42mm in diameter and the final product material is bronze. It is for sale but haven't had any prints made yet.
The goal is to test a few of these (and more upcoming types) and race them as well as offer them for sale.

There are a few brands already available and the raw castings are not very expensive ($10 - $15) but they do require balancing as well as sharpening. On top of that they are usually hand modified to adjust the pitch. The end product usually sells for $50 and up. A really good race propeller will easily sell for $100.

By calculating the profile and generating the end product like this it will be possible to offer a huge range of configurations at a reasonable cost. They will still need to be sharpened and balanced but if the Bronze prints are anything like the WSF test prints in quality the work should be minimal.

In any case it was a fun exercise.

that's awesome.

I really love the process you have gone through to show how there is value in 3D printing an object such as a propeller that arrives ready to run 'out of the box'.

It is very easy to see the cost of 3D printing as higher than other options, but in some situations there are a lot of hidden costs.

I have been going through a similar process with model train parts - comparison of an identical piece often means that the 3D printed option is more expensive (sometimes by a lot). However, I can offer a single piece in 4 or 5 variations which means a consumer can get exactly what they are after, read to go.

Thank you.

There is definitely a place for 3D printed hardware. In this case the end product could be marketable. The per item cost is higher but there is a possibility to have a 100% custom propeller made at a very reasonable cost.

Making a lost wax casting would be much more expensive.
Making a CNC milled version would also be quite expensive but would on the other hand not require any post processing.

It will be interesting to see a Bronze print.

The full scale version of the racing boats these props are used on can be seen here:

http://www.f1h2o.com/video/index.php?type=vod&idsaison=3 7&idrace=202&idcat=2

There are videos of complete races and seasons on that site too.

First print in Raw Bronze. It turned out very nice.