What kind of wind turbine is this?

4 Posts
Sep 28, 2008 10:51 pm
What kind of wind turbine is this?

Has anybody seen one of these?  I'm wondering where I can get some info and if this is an available product.  This one seemed to run at a much higher TSR compared to other VAWTs, and has a larger swept area.


351 Posts
Sep 29, 2008 12:26 pm
Re: What kind of wind turbine is this?

It is a subvarient of a Darrieus type design. The video is not clear enough to tell whether it is a Giromill or a Cycloturbine. If you trust the windspeed estimate of the photographer, it would most likely be a cycloturbine.

My guess is that it is a home built, not a production machine.
4 Posts
Sep 29, 2008 07:33 pm
Re: What kind of wind turbine is this?

Ken, you sound like you know your stuff.  Question: Giromill = fixed pitch blades and Cycloturbine = pitch of airfoils change relative to wind direction and rotation position?
351 Posts
Sep 29, 2008 08:13 pm
Re: What kind of wind turbine is this?

You have the classifications correct.

4 Posts
Oct 4, 2008 07:34 pm
Re: What kind of wind turbine is this?

I stopped by the farmer's house and got some information on the turbine.  I did some research and contacted the company that is building it.  I've updated the YouTube video info based on what they told me.
220 Posts
Oct 5, 2008 02:53 pm
Re: What kind of wind turbine is this?

�  it looks like they had you pull your video off the you tube site. and they replaced it with their own demo video with even more information. looks like a nice machine. this new design seems to fall into it's own category with the tilt rotor and changing pitch? this video looks like the same location. super cool.

heres the new link
�  http://www.youtube.com/watch?v=C4-MuOFl1ts

more info about the company (hope it's ok to post here)

all the best.
« Last Edit: Oct 5, 2008 03:12 pm by david ames »
4 Posts
Oct 6, 2008 09:07 pm
Re: What kind of wind turbine is this?

David - They emailed me and said they'd been keeping the development of this turbine pretty quiet, but they plan to have an unveiling of the product later this month. Right now this is the only one in existence, and you're right - it's totally a new approach. They said they were going to post the YouTube videos and info, so I decided to pull my video because it had obviously become moot!  I will email back the engineer and ask him to monitor this thread.
2 Posts
Oct 7, 2008 04:39 am
Re: What kind of wind turbine is this?

The Blackhawk makes a lot of sense, but they don't give any data for wattage output at various mph over time, other than producing energy when the wind speed is greater than 7mph....and producing as much as 1.5kw (per hour? at what wind speed?) up to a wind speed of 30mph.

What happens at winds over 30mph? Does the turbine peak in output and stay at that level, or does it shut down to protect itself?

The website states it will be priced "less than the standard economy car", so I'm guessing it will cost less than a $8,000 Kia? Or would that be a $14,000 Chevy/Dodge/Ford?

The life of the turbine is estimated to be "two decades at least", but the few vertical axis turbines I've found that have made it into production and whose developers WILL QUOTE PRICES all take 15-20 years for purchase costs payback at average wind speeds of 10-15mph. I have to assume those who won't quote prices (like the Finnish Windside) are so *outrageously* expensive they're embarrassed/ashamed to tell anyone.

How much do these turbines ACTUALLY COST to produce, and how much of the retail prices are attempts to funnel profits back to investors ASAP? I don't think the wind market is ever going to take off until prices are drastically reduced through mass production. Tax credits for both manufacturers and buyers wouldn't hurt, either.
16 Posts
Oct 7, 2008 12:12 pm
Re: What kind of wind turbine is this?

Hi Carla,
I am the chief engineer on the Blackhawk Project. Thank you for your observations regarding the information (or lack of it) pertaining to the AR-10 Tilt Rotor.

First, the AR-10 is not a product yet - it is currently in the middle of an extended testing cycle that is dependent on a number of factors, including wind conditions at the test site.  I'll be glad to discuss any technical aspects of the design, but until we get a large enough statistical database, I feel very uncomfortable about making any unsubstantiated claims regarding performance based on wishful thinking.  This industry is rife with that kind of stuff, and I refuse to be a part of it.  I'm trying to do my best to rein in the marketing guys, but they don't have much specific technical detail to work with - thus all the vague language.  But like most people who've watched it fly, they're pretty excited about it and want to get it on the market.

Secondly, it's impossible to keep anything a secret forever, and when you have a unit deployed, even at a remote site, it is just a matter of time before a knowledgeable person recognizes it for what it is.  Therefore we have decided to release the YouTube videos and take some control over the accuracy of the information.

This has been a fascinating project to be involved with and I've gotten some incredible support, both financially and from the CPM machine shop.  The project is internally funded and so does not need to solicit investors.  We're currently building 10 identical units for Beta site testing through the Spring of '09.  Our goal is to keep all the manufacturing in the U.S., even though we could obviously have it done cheaper in China.

It's refreshing to find a forum like this where people actually seem to know what they're talking about, and are civil.  I'd be glad to answer any questions about the design.

Bruce Boatner
The Blackhawk Project LLC
Boise, ID
220 Posts
Oct 7, 2008 09:56 pm
Re: What kind of wind turbine is this?



  thanks for taking the time and effort to join us here on the altE forum. it's not all that common to be able to discuss a new idea with the inventor.

  please correct me if some of my observations are not accurate. it looks as if your design is based on the emergency procedure called autorotation used to bring a disabled helicopter in for a safe landing after an engine failure. the common myth with helicopters is that they drop out of the sky like a brick if the engine fails. but actually when the proper inputs are used a controlled and safe landing are even more likely than with a fixed wing aircraft.

  a few questions if i may. how are you able to control the cyclic pitch of this machine? (the counter rotation caused as a byproduct of lift) also are you seeing any noticeable ground effect on the low airfoil? also have you considered installing your machine inside a caged corral of air straighting fins?

 this is a groundbreaking design..do you believe it is scaleable?

 thanks, dave. kb1mzf. asel vfr only

 and as always thanks to our hosts here at altE for making this forum possible and keeping it civil when required.
16 Posts
Oct 8, 2008 12:13 am
Re: What kind of wind turbine is this?

Thanks for the kind words.  You raise a very interesting point regarding autorotation.  You know, I've never really thought about it in exactly those terms, but in fact you're right.  (BTW I got this idea while studying aerodynamics for my helicopter pilot's exam.) 

Simply put the helicopter puts energy into the air while a wind turbine takes energy out of the air, both via an impeller.  During helicopter autorotation the airfoils are executing a very complex combination of both functions.  Now I'll have some fun thinking about that!

Surprisingly, when I conducted the patent search I found that nobody had previously associated these basic rotor head/VAWT design concepts.  The patent is called "Vertical Axis Wind Turbine With Articulating Rotor", or VAWT/AR for short.  It encompasses both the teetering rotor (2-bladed ala Bell 47/Huey/JetRanger or Robinson R22/44), and fully articulated rotor systems (3+ blades).

The cyclic pitch function on the VAWT/AR is an interaction between the tilt of the overall rotor (which is easily seen in the videos), and the instantaneous Angle Of Attack (AOA) of the airfoils (which is not easy to see).  As Ken Hall rightly observed, this is a type of Cycloturbine, wherein the AOA of the airfoils is constantly being controlled to provide a beneficial lifting force to produce rotation, based on the instantaneous relative wind impinging on the airfoils.  It is reliably self-starting, and has an interesting characteristic of being able to respond to increased loads by increasing torque.

The center of inertia of the entire system is located at a still point at the geometric dead center of the universal joint in the hub.  Thus there is no wobble or vibration at any speed or any rotor tilt angle.

The airfoils are canted in such a manner as to produce lift on two perpendicular axes simultaneously.  There's the normal rotational lift, but also vertical lift created by a fixed angle of the airfoils (pitch bearing housings) mounted relative to the rotor arms.  The lift created in the perpendicular dimension causes a tilting action...which causes the overall rotor to align itself with the wind...which causes the proper AOA to be set for each airfoil...and it's off to the races!

There's no ground effect, but we do need to get the turbine up higher into cleaner wind.  It's convenient right now to make quick adjustments.  In terms of external shrouds etc., one should consider the materials used to construct such are more efficient when "put to work" on the moving sections of the turbine, based on what I've read, anyway.

This all sounds pretty complicated, but today I sent the CNC parts for a new protytpe out for anodizing, and they all fit easily in a fairly small box.  Also the airfoils are a simple NACA 0012 style, like typical symmetrical heli blades, so there's nothing exotic for production.  So there's a relatively complex set of physics being executed by a relatively simple set of mechanics.

And we haven't even talked about how it automatically compensates for gyroscopic precession!  Way too much information, I'll bet...

16 Posts
Oct 8, 2008 12:24 am
Re: What kind of wind turbine is this?

Here are the 3 Blackhawk AR-10 videos currently posted on YouTube so you don't have to search for them.  I noticed they don't come up together on the screen when one is played:


220 Posts
Oct 10, 2008 07:57 pm
Re: What kind of wind turbine is this?

  hi folks,

 for anyone interested in wind turbines or those folks just interested in interesting things i would recommend having a look at this new wind machine.

 bruce, i looked at the video shot a few more times trying to get my head around the center of rotation.

"The center of inertia of the entire system is located at a still point at the geometric dead center of the universal joint in the hub.  Thus there is no wobble or vibration at any speed or any rotor tilt angle."

  it looks like your universal joint/hub design takes all the side to side loads as well as the thrusting loads into the hub assembly and only lets through the rotational torque to the alternator/generator. nice...that also means it's reasonably easy to swap out different spec generators based on wind resources and power needs?

 i looked up that four digit airfoil. was that 12% by design
or trial and error.

 i hope you can tell us more about your choice for the powerplant as well as the gyroscopic precession correction methods you teased us about.

 all the best.
16 Posts
Oct 10, 2008 11:00 pm
Re: What kind of wind turbine is this?

Hi David,
Thanks for your interest. When I read back over my post I thought to myself "Dude, who's going to read all this?".  Obviously you did, so...cheers!

Yes, the U-J only passes the rotational component through to the drive shaft, and maintains all the other forces neutral.  This turbine produces high torque, due to its long moment arms and large swept area, but it turns at a relatively slow RPM.

I tested the turbine without a load to determine the proper cut-in speed and operating range, then I designed a generator to match the aerodynamic characteristics of the rotor.

The AFPMG (Axial Flux Permanent Magnet Generator - really an alternator) starts producing a charging voltage of 25V at a cut-in speed of 40 RPM (0.625 V/RPM) in about a 7-8 MPH wind.  It is designed to operate mostly in the 40 - 60 RPM range but is capable of running at 80 RPM (~ 1KW) without burning out the coils based on the wire gauge I used.  Of course driving a generator to that level of output is quite a challenge indeed!

Having the basic design parameters for the very low RPM generator, it is easy to mod the stator for a 12V or 48V simply by altering the coil wraps and wire size.  The rotor/magnet wheels remain constant.  Also with its low RPM and high torque we've looked into direct mechanical water pumping.

The NACA 0012 was a jumping-off point for experimentation.  We're building a set of 14% airfoils right now.  The airfoils are foam core with thin aluminum sheeting - accurate, strong, light and inexpensive.

Gyroscopic precession - next post!

16 Posts
Oct 10, 2008 11:46 pm
Gyroscopic Precession

Gyroscopic precession seems pretty complex and mysterious at first, but in fact it is simply due to the fact that mass cannot change direction instantly - there is always a delay between the application of force and the movement of the mass.  In the case of a gyroscope, the response to a force is seen 90 degrees after the application of the force.

In other words if you press down at the 12 o'clock position, the clockwise-spinning gyroscope will dip at the 3 o'clock position.  This is simply because the mass passing the 12 o'clock position BEGINS to respond to the force, but it does not reach its full excursion until it reaches the 3 o'clock position.  No mass can respond instantaneously.

In helicopter rotor heads, the desired change to the pitch of the rotating blades must be applied exactly 90 degrees prior to the position that it will take effect.

In the VAWT/AR Tilt Rotor, gyroscopic precession must be compensated for, or the system will not run at its full potential TSR (Tip Speed Ratio - but for a VAWT, rotor speed relative to wind speed).  Here's why:

Let's say there's no wind and the AR is still, with its rotor level.  The wind begins to blow, and the rotor tilts into the wind, causing the airfoils to pitch correctly to produce rotational lift, and the rotor begins to turn.

Now the rotor starts to spin up, faster and faster, and as it does the effects of gyroscopic precession begin to take effect, causing the low tilt point of the rotor, which is supposed to be directly into the wind, to start to drift over to a point 90 degrees to the side. 

If the rotor were allowed to tilt 90 degrees off the windward mark, it would stop running very quickly, because the airfoils would not be positioned correctly to produce lift.  In fact, the airfoil that is swinging directly upwind - that should be perfectly faired into the wind - would start acting like a giant speed brake!

Early prototypes showed that without some means of correcting for gyroscopic precession, the turbines would settle into a tilt angle about 45 degrees between the optimal position and the show-stopper position.  The TSR would then be limited to around 1.5, whereas I've measured a TSR of 3 when correcting for gyroscopic precession.

How the VAWT/AR corrects for this is quite simple.  As I said before, as the rotor tilt angle starts to move away from the optimal windward position, the airfoil swinging in the upwind position begins to present drag because it is not perfectly faired into the wind.  However, due to the fixed cant angle of the airfoil relative to the rotor arm, any non-zero pitch in this airfoil is translated into a lifting force on the rotor arm, thus raising it back into its proper position. 

Remember, though, that gyroscopic precession is acting on this force as well!  But in this case it turns out to work in our favor, the final result of which is to nudge the rotor back into its proper windward tilt position.

So the airfoils are performing triple duty: 1) rotational force (produce rotor torque), 2) tilting force (orient the rotor to produce proper instantaneous airfoil AOA), and 3) correct for gyroscopic precession.  Once again, complex physics, simple design.

220 Posts
Oct 14, 2008 01:20 am
Re: What kind of wind turbine is this?

  hi folks,

  for any of you who may be following this vawt discussion on this thread. take a moment and see if you share any of the impressions that i have come to regarding this blackhawk ar-10 prototype and its designer.

  i have found this discussion to be very interesting, extremely educational and darn right refreshing.

  here we have a prototype turbine that was stumbled upon and basically outed to the public - way before its intended rollout.

  then we have the inventor sign on and proceed to give us every detail of his propriety designs on this public forum without any wild claims or requests for funding.

  i for one will be watching for the production development of this tilt rotor vawt with interest.

  edit.(i have removed a comment about project funding here..pure speculation on my part, that i later thought of as better left out).

  in any case i believe we have been treated to a look at a real project with real numbers using real engineering methods by a true pioneer!

  well done! mr. bruce boatner

cheers, dave
« Last Edit: Oct 18, 2008 01:09 pm by david ames »
1 Posts
Oct 27, 2008 08:34 am
Re: What kind of wind turbine is this?

I have been following the blackhawk ar-10 prototype. I am excited about a alternative source of power. I live in Fairfield and have many acres of land and god only knows enough wind to power the blackhawk. I would certainly be interested in having a test site set up on my property. I would love to be a part of this project. I have no brain power, however I do have wind power.  Thanks for your contributions to the earth Bruce. Thanks Marilyn Dillard
16 Posts
Oct 27, 2008 10:40 pm
Re: What kind of wind turbine is this?

Dave - you are too kind.

Marilyn, please go the the cpmach[dot]com web site and get the contact information for Dave Robison.  I have emailed him to expect your call.  Have a chat with Dave, and I'll get your phone number from him as well.  You're just down the road ... relatively speaking, from an Idaho perspective.

49 Posts
Nov 13, 2008 10:19 pm
Re: What kind of wind turbine is this?

  Thanks for the educational reading. Jim
1 Posts
Nov 28, 2008 07:19 pm
Re: What kind of wind turbine is this?

Hi Bruce,

I found your project on the internet, and I am quite impressed.

I already sent an email to David Robison, but couldn't find your contact information, so I thought I might catch you here.

I work on an Wolfe's Neck Farm in Freeport, Maine.  We are a 626 acre non-profit farm on the coast of Maine committed to sustainable agriculture, and we are currently pursuing grants to develop our solar/wind facilities.  We can't talk seriously about sustainable agriculture without also addressing energy.  We get good prevailing winds off the ocean, and our data indicates our site is promising for wind power.

We are currently sponsoring a series of talks on wind and solar energy as well, the next on January 22nd features former Governor Angus King of Maine, a wind power advocate.  Dr. Richard Komp, the president of the Maine Solar Energy Association, was our first speaker November 20th.

I saw the article on your vertical windmills and was impressed.  I am wondering what the price will be for the product?  Also, what will the availability be?

What would the possibility be of being a dealer/demo site for your product?  We are focused on agriculture and environmental education here at the farm.  This summer we will be launching our Green Energy Fellows program which will train 20 high school students in constructing solar and wind energy projects.  Each year we have more than 7000 children come to the farm for visits, field trips, farm school, and camp programs. 

Our goal is to take the word "alternative" out of solar and wind energy, and build a culture that actively plans, purchases, and constructs renewable energy facilities.

As a Maine Army National Guard combat veteran of Operation Iraqi Freedom ('04-'05), who is scheduled to return for another tour of duty in 2010, I believe it is a pressing issue for our nation to develop personal, local, regional, and national sources of energy to ease the political pressures on the political and military control and influence of the oil producing areas of the world.

Please let me know about your windmill and what we can do to be involved.

I am hopeful your prices will be accessible for small organizations.

All the Best,
M D "Mitch" Mitchell
Education Director
Wolfe's Neck Farm
Freeport, Maine 

mmitchell @ wolfesneckfarm . org  (take spaces out to reply)
16 Posts
Nov 30, 2008 11:30 pm
Re: Wolfe Neck's Farm Project

Hi Mitch,
For some reason I'm not getting alerted via email of postings, so I'm glad I happened to stumble upon your posting.  Dave did copy me on his response to your email.

Your project in Maine sounds fascinating, so congratulations.  Not to repeat what Dave told you, I'm really hoping we can work together into the future on projects of mutual interest like this.  We have found that peoples' visceral reaction to the tilt rotor turbine is quite profound when they encounter it for the first time.  I don't know exactly how to explain it, except that it has a sort of presence about it "in person" that doesn't necessarily come across in pictures & videos.  I'm sure you'd enjoy working with the machines. I'm confident the quietness and aesthetics of the turbine will fit the kind of quality plans you have in mind.

We're finishing up the CNC parts for a run of 10 production/Beta site units, which we hope to start installing in January, after evaluating a number of sites near enough to establish a "Pony Express" route for gathering test data.  The current run is also allowing us to capture the true build costs for the unit, which in turn will dictate what we can sell them for.  We've decided to build 100% of the unit here in the U.S., even though we could make a lot more money by having some of the components manufactured in China.  Currently it's looking like the Beta Site units are going to sell for around $5800, but this is UNOFFICIAL.

We plan to go into full production sometime in 1Q09, and will probably be building about 100 units per quarter, depending on demand.  Right now we have approximately 150 requests for the 10 Beta units, but until we actually start qualifying individual sites, there's no way to know how many of those are for real.

I hope you don't have to go back to Iraq, but thanks for serving.  I was an Army crewchief on a DeHavilland Otter, and some of my adventures in Viet Nam have found their way onto the internet.  No telling what the situation in Iraq will be by 2010.  Things seem to be changing pretty fast.  Perhaps in the long run the impact of your work at Wolfe Neck's Farm may be just as important for making our country more secure.

Thanks again for your interest,
1 Posts
May 26, 2009 07:59 am
Re: What kind of wind turbine is this?

A windmill is a machine that converts kinetic wind energy into mechanical energy.  A turbine is a machine that further converts that mechanical energy into electrical energy.  A turbine is also referred to as a wind energy converter.

Wind turbines are of two types; a horizontal wind turbine, which has its rotor shaft placed at the top of its body and must be pointed at the wind, and a vertical wind turbinewhich has its rotor placed vertically and at a lower point.

351 Posts
May 26, 2009 03:06 pm
Re: What kind of wind turbine is this?

You seem to be separating the mills and the turbines by the end work performed.  While it is true that windmills are best at mechanical tasks and turbines are usually making electricity, that is not what separates them.  Windmills can generate electricity and turbines can pump water.

Windmills are drag machines. Their “sails” or blades are pushed by the wind.  There is very little or no lift generated by the blades.  Turbines use airfoils that generate a substantial amount of lift.

Your belief that HAWT’s must be pointed upwind is incorrect.  While the majority of them are upwind machines, downwind designs do exist. Here is a good write up on some of the differences.


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