# Old rotary blade design



## Cap'nBill (Dec 27, 2008)

I've look at probably dozens of pics on the web looking to see if I could figure how to make a more scale blade then the vacuum cleaner blade I started with. I always wondered what was behind the 'VVVV' blades, thinking there had to be something I couldn't see. Finally happened upon these old pics. Now, how to make the' scoops'....cut funnels in half? Maybe these will inspire someone else, too.


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## Totalwrecker (Feb 26, 2009)

Use a tapered bit and mill them into wood. 
Looks like 75% circumfrence with a slot for the snow. 
Use two blocks of wood, clamped together, so the bit doesn't grab in the slot. 
Notch for the blade centers between the slots, the cutters are hinged and raised depending on rotation... 

Now the tilting blades to make them efficient is another big ol' can o' wormies, but are probably controled by centrifical force and snow drag... leading edge bites and rod pushes trailing blade down so snow is fed into slots... 

We want pics! ... the above were great 

John


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## Semper Vaporo (Jan 2, 2008)

I have cogitated on this design for a looooong time. My thoughts were to drill a series of radial, tapered holes into the edge of a disk at an angle equal to the taper, such that one side of taper is parallel to the side of the disk. and offset just far enough that it breaks through the side of the disk, producing a uniform width slot in the flat side of the disk. The disk being contained in a close fitting tube with an opening on the top to allow the snow to exit the assembly. Centrifugal force would fling the ground up snow/ice to the outer edge of the disk and out from the whole assembly. The tapered hole would hold more snow toward the outer edge than the inner volume so it could be stored for the partial revolution it would take before the opening in the tube (that the the disk is in) is reached to allow the snow to exit. A deflector at this opening would direct the snow to one side or the other depending on needs, but it would probably work best if the deflector is set to help the snow continue in the direction of rotation of the disk/blade assembly.

Over each slot formed by the tapered holes are two doors, or blades capable of covering 1/2 the slot width. The blades are hinged to the edge of each slot. The blade on one side of one opening is tied to the closest blade on the next slot such that if the disk is rotated in one direction, the snow will catch on the blade cutting into the snow and get pulled out, away from the disk and this will in turn push the next blade back into the slot it is adjacent to... or... the blade that is sliding backward over the snow would be pushed back into the slot it is over and that would pull on the blade leading it in the direction of rotation, pulling it out away from the disk to cut into the snow to pull the snow into the slot that the blade is over.

If the whole assembly is reversed in rotation, the configuration of the blades would automatically adjust so the leading blade would cut into the snow and the trailing blade would be pushed back into the slot letting the snow being cut by the next leading blade to enter the tapered hole.

The cone in the center has a couple of angled bars extending from it to drill into, grind up and push aside the snow that the blades cannot reach in the center.

The thing I cannot decide how to do is make the tool to drill the tapered hole. I am sure it can be done, I just don't know HOW. Then there is the setup of the machine to do the drilling to get the tapered holes drilled at the correct angle to produce parallel edged slots. Then how to hinge the blades securely and robustly tie the pairs together so they don't break easily. 

Real 1:1 rotary snow plows have thick metal to handle the real 1:1 snow...Miniature scale rotary snow plows have to handle the same 1:1 snow and that may be difficult to build robust enough to do so.


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## Cap'nBill (Dec 27, 2008)

Until I saw the pic above, I didn't realize the cone design of the scoops. Having thought about this a bit, my immediate solution was to look for preformed brass 'cones' that could be slit, split, or separated fairly easily.....and solderable! Roughly the radius for cones and blades would be about 2"..+, or-. I had bought some brass hinges with the idea of using these as a start point, for the blades. I don't have the equipment to do a tapered bore. I have a small lathe and thought about a brass disc of about 4" at the rear, to which the cones could be soldered. In the full size the blades are massive, movable, and flex under their own weight, and torque seems the main requirement( going by a YouTube demo). My starting point is a geared 12v motor(RC and battery powered) which would allow fairly powerful torque and variable speed. I'm guessing a 'scale', workable, snow fall would be in the 3" range. Seems to me, in some of the videos, guys are trying to penetrate snow unrealistically deep. I'm not sure if a full size rotary could handle a 12' snow.....maybe they could. Without some kind of cam arrangement, I'm not sure we could make small 'hinged' blades move under centrifigal force. In any case, it's an interesting exercise.....at least to me! Bill


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