Rotornuts and all,
Since we got goofy a few days ago speculating how and why to do do a single blade rotor, I submit the first ugly prototype.
I started with a couple of parts from propset that went to their resting places in the windy great beyond. The single blad I had that was still intact was from an old 5 ft unit that met its fate about a year ago before I learned how to do the gravity furling system that is popular on this site. The other (stubbys) cam from a 3 ft prop that the set screw on the hub (pully) worket its way lose and the entire prop came off in a big blow.
I was going to insert an image here but even though I uploaded and can view the files in my files it is not showing up the file names on the select image box.
Maybe Ill continue with the story and see if they are ready by the time I get finished and put the pics at the end.
I weighed and found the center of gravity of the 5 ft blade and then cut off the shattered tips of a couble of the 3 ft blades. I then added weights (chunks of rebar cut to the correct length to give me the needed weight) to make the stubbies weigh about the same as the 5 ft blade. I mounted the stubbies and the 5 ft on a well used wooden hub in the appropriate 120 degree spacing. I then glued the rebar pieces to the ends of the stubbies and tested the balance. The assembly was heavy on the 5 ft end so I started attaching small magnets to the rebar until I go it pretty closely balanced. I cut some additional ssmaller pieces of rebar to match the weight of the magnets used and glued them on then did some additional fine balancing. To balance it all I did was insert a long shaft into the hole in the center of the wooden hub and rest it on a level smooth flat surface (or the corners of pieces of angle iron setting on a table work well). I balanced it only in one (rotational) plane. It is quite possible that the center of mass of the stubbies relative to the center of mass of the 5 ft blade may not forward or behind as viewed from the edge of the prop. But it would rotate with little to no favor for a heavy blade. I then mounted a small pully to the wooden hub and mounted the thing to an old converted fan motor I had laying around and then mounted it on my quick and dirty small mill plarform with tail attached. Took it outside far away from anything and set it up. And guess what .... no wind. I thought today would be a good day to do this as earlier there wer just gentle breezes in the 3 to 7 mph range. I didnt want to try this thing in any real wind due to the precarious nature in which I threw it together.
I see I still cannot view my files in the select file to insert box so I will try copy and pasting the shortcuts.
What I started with above,
The stubbies and 5 ft blade mounted on the rotor hub. The rebar is attached to the stubbies.
The whole assembly, ugly as it is.
Waiting for a puff of wind.
Ill be back with the rest of the story after I get some wind. And please understand I realize this setup looks and is pretty precarious, unguyed pole, rebar possibly flying off into my head if im not careful etc. Just had to do something to see if it works.
Johnlm
I think I got the right pictures in the right spots for you.
Tom
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