Decorative American farm windmill fail video

[tractorgp]

I bought this windmill kit years ago and finally got around to putting it together and modifying it to have overspeed control (I paid about $50 for it at the time). On the first test the rotor and yaw bearings failed so I installed new rotor bearings and upgraded the yaw bearing. I used a well tested overspeed technique that has been in use in these farm windmills for more than 100 years... the rotor is hinged with the tail and under some kind of resistance to fold or furl. With this windmill I went with relatively light tension provided by an extension spring. Although I didn't make any kind of measurement I think furling was taking place after 30 or so mph.

So everything went fine for about an hour or so but it looks like a strong wind gust forced a blade into the spring support arm... and thats how the self-destruct process started. At least that's what I think happened - I'll take a closer look later today.

The wind speed was up to about 80 km/h at the time (about 50 mph) of the incident.

(These windmill kits are still available on ebay but they don't come with any form of overspeed control)

 

[coolreinfarm]

I have a very similar windmill I bought from harbor freight many years ago with out the speed control, just greased it a few times a year it takes 50 mph winds with no problems. I’d check those lights out, I bet the blades damaged the wires.

 

[zzvyb6]

Interesting. I have 9 vintage water pumping windmills on my ranch (Flint & Walling and Baker Heller-Aller models). To get the 'governor' effect properly working, you need to offset the tail hinge a few inches in the rear view. This makes the fan turn away from the wind while the tail tries to keep it aligned with the wind. The tail spring, when properly sized (for stiffness) gets you wind protection. In strong winds, the fan would be completely furled. In calm winds, the fan would be facing fully into the wind.

 

[George2615]

Looks like the fan blade welds let loose where they connect to the inner and outer rings. Blades are still on the outer ring.

 

[oldballs]

This one has taken 70 mph winds so far...but it is just a "wannabe".

 

[buckeyefarmer]

I had one that lasted years.

 

[tractorgp]

Looks like the fan blade welds let loose where they connect to the inner and outer rings. Blades are still on the outer ring.

After looking closely at the video and the windmill (on the bench) I concur with your analysis.

In the video at the beginning of 0:58 (normal speed part) and 1:08 in the slo-mo part you see a blade (maybe blades) come loose and when that blade(s) continues turning in the circle of rotation it slams into the spring support arm and bends and twists it in an upwards direction.

Then, at 1:08 in the slo-mo view the extension spring flies away (from being violently stretched by the distorted support arm) and finally disappears from view at 1:16. The spring was the only component that actually got away from the windmill, I found it on the ground a short distance from the tower.

I found it amazing the amount of bending and distortion of parts (as seen the video) that took place during the event. While mounted on the bench I tried to duplicate the distortions observed in the video by applying force at different points on the windmill - I wasn't able to bend to the same degree.

So the free flying blades (ended up being three) held on by the outer ring, made contact with the tree lights and sliced the tip off one of them... but that was collateral damage, the xmas lights are not to blame for starting the event. I Will probably change the video title to reflect this.

 

[tractorgp]

Interesting. I have 9 vintage water pumping windmills on my ranch (Flint & Walling and Baker Heller-Aller models). To get the 'governor' effect properly working, you need to offset the tail hinge a few inches in the rear view. This makes the fan turn away from the wind while the tail tries to keep it aligned with the wind. The tail spring, when properly sized (for stiffness) gets you wind protection. In strong winds, the fan would be completely furled. In calm winds, the fan would be facing fully into the wind.View attachment 531584View attachment 531585

Yes the rotor is offset from the tail and it worked fine until the incident described in the video happened (see my analysis below in response to George2615)

 

[oosik]

zzvyb6 - don't think I've ever seen a windmill with so many blades. Like the look on your face - how high there - 35 feet?? And what took the pics - they are straight on, not angled up.