Some more nacell renderings V0.2

[wgatenson04]

Here is my second attempt, please feel free to critique, nothing will hurt my feelings.  The bolts, blades, brake, and stator are not shown in this rendering.  That is a hinge on the front of the pic, not rendered very well.  Thinking of replacing the pillow blocks with U-bolts.  Thoes steel peices on the top are 1" thick each.  Bearings are 2, dual row angular contact bearings.  The shaft is 2"D hardend steel.  Disks are 24" D with 40 (3/4" x 2" x 1/4") N40 neos on each.  Output has been estimated arround 5kw, even though the genny has not been tested yet.  Thoes results will derermine exact blade size and TSR.  Yaw bearing is 4" pipe with a 1/2" wall on a 3" pipe with a 3/4" wall, and a thrust bearing on top of the 3" pipe.

[wgatenson04]

[wgatenson04]

The tail, or the yaw control motor are not snown either.

[kitno455]

hello again

where are the thrust faces on the rotor shaft? pillow blocks dont like side load. ubolts are worse your tapered roller bearings will do it, if you have shoulders cut into the shaft. but then the pillow blocks are completely unsupported on their lower side...

yaw bearing is much better now.

what is the point of the hinge? is that your furling device? if so, it is going to tend to bend toward the tower at the bottom under load. the opposite of what you want.

you are going to have some point where the rear of the hinged part makes contact. then, due to the distance of the mainshaft from the hinged section, you are going to have a noticable bending moment around that point of contact. 2 inch thick steel is not really a good answer. a hollow, 3-d section is better than a thick flat bar. lighter and easier to build too.

allan

[wgatenson04]

yes the hinge is for furling, and the bolts and structure won't allow it to go less than 12.5 degrees.  I would imagine because the top blade is more perpendicular to the wind speed, it should have more of a linear load than the bottom half of the hub, then again I could be wrong.  

If I swich to U-Bolts, I will probiblly have to add a "stop plate" behind the shaft to stop it from sliding back.  

[kitno455]

so you plan to have some kind of piston or screw motor where that hinged part makes contact? (and use a bit of electronics to drive that device?)

have you looked at the dragonfly? it uses the propshaft above the hinge, and it leans back into the wind against a spring/damper or some such. i like that design better, since it will require less active management (wind dies down, prop drops naturally).

always keep in mind what will happen when your electronics break. that is where a fixed tail and a mechanical furling system, if kept simple enough, will often win out.

allan

[Dave B]

Looks very interesting and I see it as a down wind machine (wind blowing left to right). If the rotor ends up balanced as shown then gravity will hold the  blades near perpendicular to the wind. High winds will over come gravity and the blades will "hinge" or swing upward (more horizontal) to effectively furl the blades out of the wind. The amount of tilt will vary with the higher wind speed chosen at which to start to furl. This should allow fairly consistant power even in high winds. Just my look at it, nice drawings.  Dave B.

[kitno455]

unfortunately, with a big prop, the forces on the top half of the blade are often a bit stronger than the bottom, since the windspeed increases at higher altitudes, and there is a turbulent 'shadow' behind the tower on the bottom. so as a down wind, you will be fighting those forces.

to get the best effect, use an upwind with the propshaft above the hinge.

allan