Sunday, June 24, 2007

Whirligig #37 on Youtube

Whirligig #37 is on my YouTube channel. (http://www.youtube.com/watch?v=t9V-Gpm0o5Q) Wednesday, June 20, I woke up to a typical New Mexico wind gusting to 30 mph (http://en.wikipedia.org/wiki/Beaufort_scale.) I took #37 out to a flat near the paved arroya a short distance from our house. At second 53 of the video I turn down Wynton’s trumpet so you can hear the whistling. What sounds like birds chirping is the whirligig. I’m not sure what’s making the metallic clicking noise. That may interesting to add on purpose.
 
Obviously, I have to make some technical improvements. Spinning in a 30 mph wind, the air movement across the sound tube openings is more than enough to produce a sound. The center blade set and its open tube is spinning in the opposite direction from the other two blade sets. This may be causing turbulence so that air does not pass over the tube openings for the second and third blade sets smoothly enough for them to sound continuously. The rapid wind direction change is probably affecting the sound too. I need to (Well, I don’t need to but, you know.) find a way to determine rotational speed.
Posted by Chuck at 18:31:56 | Permalink | Comments (1) »

Sunday, June 17, 2007

Whirligig #37

Whirligig #37, 22″ x 18 1/2″ x 8 3/4″ (56cm x 47cm x 22cm), aircraft plywood, African mahogany, brass and assorted metal parts, sign paint

Whriligig #37

Three Independent Twirling Blades Sets

Shiny Brass Blades

Three Musical Tubes in C, E and G

Zypher Rated*

*blade rotation with 2 mph breeze 

Detail of Hub Assembly

I only finished this whirligig yesterday afternoon. There hasn’t been a wind significant enough to get it up to sound making speed. In fact, I don’t know if it will whistle at any speed. I only know that when I blow over the hollow brass tubes, I get a sound. The collars on the arms balance the blade sets.

 

Posted by Chuck at 05:35:05 | Permalink | No Comments »

Friday, June 1, 2007

Whirligig #36

 

Brass blades for Whirligig #36

Whirligig production has slowed from a spin to a crawl. Whirligig #36 did not work. I expected that V-shaped blades would rotate horizontally on a vertical axle; the force of the wind in pocket of the V would be greater than the force of the wind against the point of the V. It simply did not work, even a little bit. The blades were 4” (10 cm) high. Maybe I can use the blades in a different context.

Next was Whirligig #37. I attempted to use aluminum sheet for the vane, but it was too flexible. Since I had already made the mast and other parts, I made an aircraft plywood vane to replace the metal one. I will have to use heavier gage aluminum or make a design that includes bends and folds to stiffen the vane. For # 37 I am using a heavy walled ¼” brass tube (.29” wall thickness) to hold the blades. I have bought all the ¼” thick walled tubing in Albuquerque. I ordered some over the internet, but when the order arrived, the tubing was the wrong size. The reshipment has yet to arrive. When the correct size gets here, I’ll finish the blades for #37. There will be four arms, but only three will have blades. The fourth arm will carry a thin walled ¼” tube that I hope will whistle. Balancing the whistling arm against the opposite blade-carrying arm should not be difficult. I’ve already weighed out the pieces. The spinning asymmetrical blade arrangement should be appear interesting, as there will be three blade hubs as in #30 and #32 and three differently pitched hollow tubes.

Posted by Chuck at 05:09:34 | Permalink | No Comments »