The new rotor pulleys and axles are starting to be tested. At the end of November, the first rotor pulley as completed and before moving on to the other 3 pulleys, the first pulley was tested to ensure that the design was acceptable. To do this, Goliath was set up with just the single sided belt, with the new pulley with the original flight rotors and one old pulley with a dummy rotor. The original flight rotors were used so that if something breaks, I won't run the risk of having to make more update rotors. This test was number 27. The video for tests 27 and 28 is below:

The first test went well. The rotor was run at idle for a while and the new pulley showed no issues and all of the bolts held. The one thing that is obvious in the video is that the nut underneath the pulley comes loose. The nuts above and below the pulley are held in place with external toothed lock washers. The don't always hold though, probably because it's difficult to tighten the nuts correctly when the rotor is attached to the pulley. After gaining some experience with machining the rotor pulleys, it was time to start making custom axles.

The axles are just 5/8" drive shafts, 12" long (5947K14 from McMaster-Carr). The drive shaft and rotor are held in place using bowed E-clips (98398A140 from McMaster-Carr). I was a little hesitant to use E-clips to hold the thrust from the rotors considering they are only grabbing onto a small groove in the shaft. A look a the specs though show that the E-Clip is rated to about a 1000 lbs. The rotors will be putting out 70 lbs at max thrust, so there's a Factor of Safety of about 14.

The machining went ok. I don't have the right grooving tools for this, but those are more expensive. If I end up doing this more, I'd get more appropriate tooling. Here's a shot of one of the grooves.

Below is the E-clip compared to the bearings that are used. (Note this was just a test fit with the bearings in the old bushings)

The overall axle has six grooves. Where the axles attach to the frame, I've left room for large washers to act as shims. This way I can adjust the height +/- the width of one of the washers. Once assembled the axles simply slides onto the frame with the frame between two of the washers.

The entire assembly with the axle, E-clips, shims, rotor, rotor pulley and rotor bolts weighs 4.9 lbs.

For test 28, Goliath was configured again with just the single sided belt. One of the rotors has the new pulley and the new axle. The other rotor has a new pulley, but with the old axle setup. Both rotors have the original flight rotors.

The pulleys are still holding up and the axle also didn't have any issues. There is some unidentified nose in the test, that needs to be figured out. Either the belts are getting clipped by the rotors or the tensioner isn't configured correctly. That issue needs to be figured out and then additional testing can be done with more hardware.