Hrs: 24

Nose wheel strut reduce friction

One post but actually work of the past days to reduce the force to rotate the nose wheel strut.

The nose wheel strut took quite some force to rotate and it felt as if the tube was oval and not perfectly round. After disassembling the strut the problem became obvious: there was a nick and a dent at the top of the strut:

Sling technical advised to sand the nick smooth and that this would not make the strut unsafe to use. So after quite some sanding the nick was “removed”. The dent is still there but no factor since this location is inside the top bushing. Furthermore the top part of the strut was sanded down by 0.1 mm so that the needle pin thrust bearings could rotate freely:

Free movement of the bearings and washers:

Next was painting the strut with black DTM paint (direct to metal). This paint doesn’t need a primer and that limits the thickness of the paint:

The engine mount needed a bit of touch up where the control horn hit the engine mount. First primer and thereafter the same gray color:

After the paint was cured the strut could be assembled again. Some grease was applied to the bearings:

In multiple iterations the strut was mounted and tested for easy movement. The top bushing and thrust bearing rotate freely now. The lower bushings cause a lot of friction. With multiple grits of sandpaper they were sanded down a little bit:

The bushing received some grease as well:

I noted that the bushing were not equally split in half. The best combination was made and the bushings marked:

About 1-2 mm difference in height:

When the lower and upper bushings are not perfectly aligned there will always be friction. On the Sling Builder Facebook group some builders advised to use a dowel or pvc pipe with sandpaper:

After another re-installation the friction was mostly removed:

However I think it’s not yet perfect, so I will order new bushings and start from scratch and only use the pvc pipe method. To be continued…