Rebuilt thrust hub

Since I was having trouble with the lift fan propeller and I've tested it more than the thrust fan I decided to do the same operation for the thrust fan just in case.

Dissassembling it there were no major signs of wear from spinning like the lift fan which had shavings everwhere and clear galling and grooves. There is a little bit of wear.

The thrust fan shaft after 

The collet freshly removed

Since I used the end cap in the middle of the lift engine hub I needed to make another one. 

Here's the end result, not pretty, but effective enough. 

The hub assembled with longer bolts extra washers and locknuts.

The final assembly from slightly behind.

The hub before assembly with the keys installed.

The keys and bolt in a fit check. 

And here's the evidence that the fan stayed on. For at least 5 minutes....



While running this test I was watching closely for wear and tear and any malfunction. And I noticed that the grill protecting the fanwas flexing quite a bit when I throttled up. So I setup the camera in a different vantage point. Sorry it's a little bouncy since the tripod is now on the hovercraft. But you can see the grill flex when I throttle up best by watching how much of the engine shaft you can see.

TODO lift

I also did some continued testing of the lift fan. I found two more points of failure. Since i've dissassembled and reassembled the lift fan so many times, two of the screws holding the grill down wiggled out of place. it was kind of exciting to watch one of them start bouncing across the grill and then disappear between the wires never to be seen again. One more reason I'm glad that I have the metal housing. And there's the thick piece of wood between me and the lift fan too.

I filmed the lift engine tests but unfortunately the gopro had operator error and so I have two unexciting pictures for each test. One before the test, and one after the test. During this test I was excited to realized that the tilting of the hovercraft does effectively allow me to move it side to side by releasing air out from the side of the skirt. By leaning I could choose to loosen or tension the docking lines on either side of the vehicle.

The other interesting result of the lift engine test was the below grill failure. As far as I can tell this wire was vibrated free from its housing. It does not appear to have had a traumatic experience from cutting and just sprung itself loose from a weakness in the weld under the high vibration environment of the lift engine.

The one piece of wire that has proven to be not well attached.  You can also see the hold where the sheet metal screw has self vacated. 

The whole loose strand, and both screw holes which were vacated.

I am going to be looking for ways to decrease the vibrations of the lift engine. Mounting it on the two horizontal bars is generally strong enough but leads to a lot of resonances which I think are making everything harder to keep in place. And also makes things louder and less comfortable on the craft.