Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

OT: Wind turbine

Matronics Email Lists Forum Index -> Kitfox-List

View previous topic :: View next topic

Author Message

Michel

Joined: 10 Jan 2006
Posts: 966
Location: Norway

Posted: Tue Feb 26, 2008 1:47 pm Post subject: OT: Wind turbine

 	  Quote: 	
		   From: Marco Menezes [msm_9949(at)yahoo.com]

 Are we sure the prop on that machine was facing into the wind?


	


Norway doesn't have any wind turbines, Marco. We have plenty of hydro-energy from the waterfalls. But as soon as you cross the border to Sweden and even much more when you come to Denmark, north Germany and The Netherlands, they are everywhere and I really mean: everywhere! Even in the final approach line of airfields.

All those I have seen (the actual accident happened in Denmark) have the rotor facing the wind. They don't have a wind vane to turn them mechanically, instead they have a tiny one that activated a step motor to turn them. What was also strange in the video is that the rotor was turning very, very fast. Probably way above what it was designed for. Usually, once they have enough wind, they turn at a constant speed. If the wind increases, so does the pitch and the produce more electricity. But, from all my days of flying and sailing in those regions; they are either stopped, or moving at a constant speed. I even remember being in Scheveningen, in the Netherlands, harboring a storm in the harbour and looking at the wind turbine at the entrance of it. It turned quite slowly.



Cheers,

Michel Verheughe

Norway

Kitfox 3 - Jabiru 2200

Do not archive

<pre><b><font size  color="#000000" face="courier new,courier">

- The Matronics Kitfox-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Kitfox-List

_________________
Kitfox 3 - Jabiru 2200

JohnA

Joined: 22 Dec 2007
Posts: 26
Location: Woodland, CA

Posted: Tue Feb 26, 2008 4:48 pm Post subject: OT: Wind Turbine

Actually what I was getting at was that the turbine reacted according to 

the laws governing a gyroscope - that is, a gyro will react 90 degrees 

to the force applied to it.  The departing blade left an imbalance which 

tried to turn the turbine.  The 90 degree rule dictated (in this case) 

that that action should express by nodding down and the blade whacked 

the pylon.



This is something we get ground into us in gyro training.  When you tilt 

the rotor back to flair to land, the gyro will tend to tip left or 

right, depending on the rotation.  This is pronounced in larger gyros.  

Likewise (with mine), left stick would induce a forward pitch.  You 

learn to deal with it.



With the turbine in question, the force of the wind on the blades is 

negligible compared to the outward centrifugal forces from the rotation 

of the blades.  There will have been very little coning effect due to 

the induced rigidity of the rotor disk.  The first blade simply failed 

mechanically as will any blade if you spin it fast enough.  From there, 

the dynamic imbalance created pure havoc in a very short period of time.



The important lesson there is that all rotating parts should be in 

excellent balance.  The weight of smashed bugs were enough to induce 

significant stick-shake on my gyro with a 25 foot rotor and it only spun 

at 350 rpm.  The weight of a 1cm square of duct tape at the tip of a 

prop will induce a lot of vibration.  Vibration robs performance, 

shortens engine and airframe life, and fatigues the pilot.



I'm still in awe of the Carbon Cub, though.



John Alexander



Noel Loveys wrote:

[quote] 



 Michel:



 I think waht john was getting at is on a gyro the high pressure area is

 under the rotor...  the same side as the axel that carries it.  On the

 generator the high pressure is opposite the axel which would make the cone

 effect to occur toward the axel or into the support.

 Noel



 --

- The Matronics Kitfox-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Kitfox-List

_________________
John Alexander
Woodland, CA

Michel

Joined: 10 Jan 2006
Posts: 966
Location: Norway

Posted: Wed Feb 27, 2008 1:36 am Post subject: OT: Wind Turbine

 	  Quote: 	
		   From: John Alexander [alexandj(at)preachain.org] 

 Actually what I was getting at was that the turbine reacted according to 

 the laws governing a gyroscope


	


Thanks John, very interesting.



(at)Noel. Yes, I was wrong in my first assumption. But my last email was about the departing of only one blade.



John, isn't the rotor of a gyrocopter simply a revolving wing? I mean, you can't change the pitch of it, can you? We have a nice Xenon gyrocopter at our airfield and I am pretty sure that both blades of the rotor are joined together in a way that it would be impossible for only one blade to depart.



http://www.gyrokopter.no/xenon_firstflight_norge.html



Cheers,

Michel Verheughe

Norway

Kitfox 3 - Jabiru 2200



Do not archive

<pre><b><font size  color="#000000" face="courier new,courier">

- The Matronics Kitfox-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Kitfox-List

_________________
Kitfox 3 - Jabiru 2200

JohnA

Joined: 22 Dec 2007
Posts: 26
Location: Woodland, CA

Posted: Wed Feb 27, 2008 9:12 am Post subject: OT: Wind Turbine

The majority of gyroplanes have fixed pitch, 2-bladed rotor systems and 

yes, it's a rotary wing system.  The blades are typically VERY strongly 

connected to the center hub bar and blade departures are rare, but occur 

upon blade strikes and (very rarely) mechanical failure of the blade.  

Flying one is all about energy management.  Gyros are always in 

autorotation.

The first thing I saw with the Xenon design is that he is NOT going to 

want to yaw the airframe very much while in flight.  The frontal area 

ahead of the rotor mast looks like it somewhat exceeds the area of the 

vertical stabilizers.  The Air and Space 18A (one of 2 certified gyro 

types) was strictly limited in yaw.

It's a really spiffy looking design though.  I'd love to fly it.

John Alexander

Michel Verheughe wrote:

 	  Quote: 	
		  > From: John Alexander [alexandj(at)preachain.org] 

> Actually what I was getting at was that the turbine reacted according to 

> the laws governing a gyroscope

>     

 Thanks John, very interesting.

 (at)Noel. Yes, I was wrong in my first assumption. But my last email was about the departing of only one blade.

 John, isn't the rotor of a gyrocopter simply a revolving wing? I mean, you can't change the pitch of it, can you? We have a nice Xenon gyrocopter at our airfield and I am pretty sure that both blades of the rotor are joined together in a way that it would be impossible for only one blade to depart.

 http://www.gyrokopter.no/xenon_firstflight_norge.html

 Cheers,

 Michel Verheughe

 Norway

 Kitfox 3 - Jabiru 2200

 Do not archive

 <pre><b><font size  color="#000000" face="courier new,courier">

 </b></font></pre>

- The Matronics Kitfox-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Kitfox-List

_________________
John Alexander
Woodland, CA

Michel

Joined: 10 Jan 2006
Posts: 966
Location: Norway

Posted: Wed Feb 27, 2008 1:03 pm Post subject: OT: Wind Turbine

On Feb 27, 2008, at 6:04 PM, John Alexander wrote:

 	  Quote: 	
		   The first thing I saw with the Xenon design is that he is NOT going to 

 want to yaw the airframe very much while in flight.


	


Could be, John. I don't know anything about those strange birds. 

Incidentally I was going to fly formation with this gyrocopter to 

another place for a fly-in, last fall. But before departure, he wanted 

first to take some photos together with a photographer. He went up and 

the photographer opened the  plexiglas door when it broke in two, one 

part felt but, in the process, hit the tip of one of the Rotax's 

propeller blades. He did a perfect landing on idle and the gyrocopter 

went into the hangar. The owner then became my right seat passenger for 

the fly-in.



Cheers,

Michel Verheughe

Norway

Kitfox 3 - Jabiru 2200

Do not archive

- The Matronics Kitfox-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Kitfox-List

_________________
Kitfox 3 - Jabiru 2200

Display posts from previous:

	Matronics Email Lists Forum Index -> Kitfox-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum