Inspiration for Homebuilders

Orval Fairbairn wrote:
In article ,
Charlie wrote:


Orval Fairbairn wrote:

In article ,
Jerry Wass wrote:


Orval Fairbairn wrote:

In article ,
Brian Whatcott wrote:


Orval Fairbairn wrote:

In article ,
Brian Whatcott wrote:


This is a pointer to a home build 20 ft diam windmill on a 70 ft pole.
It features three 10 ft long laminated red cedar blades and nice
looking
generator, tower couplings and gin....


http://www.otherpower.com/20page1.html

Brian W

(Thanks to Larry for the pointer on rec.boats)

I hope that you have good lightning suppression!


Ha! I noticed the maker specified a blade angle of 3 degrees at the
tips, increasing to (approaching) 9 degrees at the roots.
It took me a little while to get my head round this. The maker mentioned
the blades are set flat (undersurface) forward into the wind, and I
think he mentioned a target rotation rate of 65 rpm.
I imagine he was thinking of an AoA of 15 degrees at the rated wind. The
tips do a revolution in pi x 20 ft = 63 ft per rev - so the rotation
rate at 65 rpm would give a tip speed of 65rpm X 63ft/rev X 60 min/hr /
5280 ft/mile or 47 mph.

I guess the pitch angle for zero AoA at the starting windspeed 16 mph
would be atan 16/47 = 19 degrees from the plane of revolution, so for 15
deg AoA the pitch angle might be 4 degrees from the plane of revolution
at the tips.
And he mentions 3 degrees. But getting up to speed with stalled blades
would be an issue...
What's your take, Orville?


Regards

Brian W

My first take is that you misspelled my name.

We had a big windmill on our farm when I was growing up. The plane of
rotation was parallel to the wind, rather than at a right angle. The fan
acted more as a wind turbine than a propeller. IIRC, the fan had about a
dozen curved steel blades. It also had a brake on it for when the winds
got too high.


The blades were turned sideways (parallel to the tail) if they didn't
want it to pump any water---If you needed water you operated the lever
that placed the blades perpendicular to the rudder, tail,
whatever,-pointing into the wind, then you got some POWER..---OR--
did you have one of those weird looking things where the blades were
raked back severely at an angle about like the back 2/3 of a snowcone
cup? Jerry

Neither. The fan was 10-12 ft diameter, fixed so the wind would always
turn the fan. Since the blades were curved (cambered), the advancing
blade had less drag than the receding blade. I think it was a
Fairbanks-Morse product, but don't hold me to that, and it was built
about 1910.

A lot of windmills in our area (Northern Illinois) were of similar
design.


Sounds like a pelton wheel.
http://www.google.com/search?hl=en&q...on+w&aqi=g 10


Nope -- it wasn't a Pelton Wheel!

As I posted earlier, I thought it was a Fairbanks-Morse model.

See the picture at: http://www.agwt.org/store/FairbanksWindmill.htm

The fan disc was parallel to the wind direction. This raises the
question: Could we dispense with the directional pivot and mount the fan
horizontal to the ground? It should be able to rotate with any direction
of wind.

Of course, good lightning protection is a MUST!

A windmill with the fan mounted horizontal to the ground is called a "vertical axis wind turbine". The Savonius and Darrieus are
examples of this.

On a Fairbanks-Morse type windmill, when the vane is parallel to the disk, it is "out of gear" (according to the windmill brochure I
found). As wind speed increases above 15 MPH, the disk of the windmill turns more and more away from the wind to maintain constant
RPM. At very high wind speeds, the disk is parallel to the wind and a brake is engaged to stop it rotating altogether. To take the
windmill off line, (as you would if you've upgraded to an electric pump), you lock the vane and the brake in the furled position.
http://vintagewindmillpartslist.com/FMWGtrade.pdf

John Kimmel wrote:
Orval Fairbairn wrote:
In article ,
Charlie wrote:


Orval Fairbairn wrote:

In article ,
Jerry Wass wrote:


Orval Fairbairn wrote:

In article ,
Brian Whatcott wrote:


Orval Fairbairn wrote:

In article ,
Brian Whatcott wrote:


This is a pointer to a home build 20 ft diam windmill on a 70
ft pole.
It features three 10 ft long laminated red cedar blades and
nice looking generator, tower couplings and gin....


http://www.otherpower.com/20page1.html

Brian W

(Thanks to Larry for the pointer on rec.boats)

I hope that you have good lightning suppression!


Ha! I noticed the maker specified a blade angle of 3 degrees at
the tips, increasing to (approaching) 9 degrees at the roots.
It took me a little while to get my head round this. The maker
mentioned the blades are set flat (undersurface) forward into the
wind, and I think he mentioned a target rotation rate of 65 rpm.
I imagine he was thinking of an AoA of 15 degrees at the rated
wind. The tips do a revolution in pi x 20 ft = 63 ft per rev - so
the rotation rate at 65 rpm would give a tip speed of 65rpm X
63ft/rev X 60 min/hr / 5280 ft/mile or 47 mph.

I guess the pitch angle for zero AoA at the starting windspeed
16 mph would be atan 16/47 = 19 degrees from the plane of
revolution, so for 15 deg AoA the pitch angle might be 4 degrees
from the plane of revolution at the tips.
And he mentions 3 degrees. But getting up to speed with stalled
blades would be an issue...
What's your take, Orville?


Regards

Brian W

My first take is that you misspelled my name.
We had a big windmill on our farm when I was growing up. The plane
of rotation was parallel to the wind, rather than at a right
angle. The fan acted more as a wind turbine than a propeller.
IIRC, the fan had about a dozen curved steel blades. It also had a
brake on it for when the winds got too high.


The blades were turned sideways (parallel to the tail) if they
didn't want it to pump any water---If you needed water you operated
the lever that placed the blades perpendicular to the rudder, tail,
whatever,-pointing into the wind, then you got some POWER..---OR--
did you have one of those weird looking things where the blades
were raked back severely at an angle about like the back 2/3 of a
snowcone cup? Jerry

Neither. The fan was 10-12 ft diameter, fixed so the wind would
always turn the fan. Since the blades were curved (cambered), the
advancing blade had less drag than the receding blade. I think it
was a Fairbanks-Morse product, but don't hold me to that, and it was
built about 1910.
A lot of windmills in our area (Northern Illinois) were of similar
design.


Sounds like a pelton wheel.
http://www.google.com/search?hl=en&q...on+w&aqi=g 10



Nope -- it wasn't a Pelton Wheel!
As I posted earlier, I thought it was a Fairbanks-Morse model.
See the picture at: http://www.agwt.org/store/FairbanksWindmill.htm

The fan disc was parallel to the wind direction. This raises the
question: Could we dispense with the directional pivot and mount the
fan horizontal to the ground? It should be able to rotate with any
direction of wind.
Of course, good lightning protection is a MUST!

A windmill with the fan mounted horizontal to the ground is called a
"vertical axis wind turbine". The Savonius and Darrieus are examples of
this.

On a Fairbanks-Morse type windmill, when the vane is parallel to the
disk, it is "out of gear" (according to the windmill brochure I found).
As wind speed increases above 15 MPH, the disk of the windmill turns
more and more away from the wind to maintain constant RPM. At very high
wind speeds, the disk is parallel to the wind and a brake is engaged to
stop it rotating altogether. To take the windmill off line, (as you
would if you've upgraded to an electric pump), you lock the vane and the
brake in the furled position.
http://vintagewindmillpartslist.com/FMWGtrade.pdf

I notice that the design which started this thread seems to have a
particularly simple wind overspeed unloader.
The mill rotation axis is offset to one side of the mast rotary
bearing, and the tail vane is offset to the other side of the mast
bearing, but it is also set on a pivot tube oriented 45 degrees or so to
the vertical. The M.O seems to be that excess wind tries to "fold the
fan and the tail in two, resisted by the tail's lifting away from the
horizontal as the wind blows harder.

Brian W