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Winglets or modified winglets?

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pequeajim

Joined: 03 Sep 2006
Posts: 708
Location: New Holland, PA

Posted: Sat May 05, 2007 4:35 pm Post subject: Winglets or modified winglets?

Has Arion considered using modified winglets on the Lightning? Would there be any advantages to doing this?

Rick

Joined: 24 Jul 2006
Posts: 113
Location: Colonial Beach, Virginia

Posted: Sat May 05, 2007 4:48 pm Post subject: Winglets or modified winglets?

Lets just say it has been "discussed"...  



Rick

N727RB



 	  Quote: 	
		  From: "pequeajim" <pequeajim(at)gmail.com>

Reply-To: lightning-list(at)matronics.com

To: lightning-list(at)matronics.com

Subject: Winglets or modified winglets?

Date: Sat,  5 May 2007 17:35:27 -0700






Has Arion considered using modified winglets on the Lightning?  Would there 

be any advantages to doing this?




	


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N1BZRich(at)AOL.COM
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Posted: Sat May 05, 2007 6:53 pm Post subject: Winglets or modified winglets?

Jim,

     Interesting you should ask about winglets.   Pete, Nick, and I spent some time discussing wing tip extensions (as well as  other changes) while at SNF.  Their fiber glass expert from  Wisconsin (Rick Disher  ?) was there as well and he, Pete, and  I actually walked around looking at various examples of tip extensions -  some with winglets.  Rick took some photos of the Lancair and Toxo  tips.  He has a great eye and it will be interesting to see what he comes  up with.  The idea for tip extensions will be to lower the stall speed  (without using VGs) for those wishing to fly with a sport pilot license.   If the new tip can add about 5 square feet of wing area per side it should  be no problem for Lightnings built to 1320 gross weight to easily make the 45  knot stall requirement.  

 Blue Skies,

 Buz



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  [quote][b]

pequeajim

Joined: 03 Sep 2006
Posts: 708
Location: New Holland, PA

Posted: Sat May 05, 2007 8:00 pm Post subject: Winglets or modified winglets?

Thanks for the info Buz.  What do the winglets do for the top end?  

         

  

From: owner-lightning-list-server(at)matronics.com [mailto:owner-lightning-list-server(at)matronics.com] On Behalf Of N1BZRich(at)aol.com

 Sent: Saturday, May 05, 2007 10:53 PM

 To: lightning-list(at)matronics.com

 Subject: Re: Lightning-List: Winglets or modified winglets?  

  

     

Jim,  

    

    Interesting you should ask about winglets.  Pete, Nick, and I spent some time discussing wing tip extensions (as well as other changes) while at SNF.  Their fiber glass expert from Wisconsin (Rick Disher  ?) was there as well and he, Pete, and I actually walked around looking at various examples of tip extensions - some with winglets.  Rick took some photos of the Lancair and Toxo tips.  He has a great eye and it will be interesting to see what he comes up with.  The idea for tip extensions will be to lower the stall speed (without using VGs) for those wishing to fly with a sport pilot license.  If the new tip can add about 5 square feet of wing area per side it should be no problem for Lightnings built to 1320 gross weight to easily make the 45 knot stall requirement.    

    

Blue Skies,  

    

Buz  

  



 

         

  

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N1BZRich(at)aol.com
Guest

Posted: Sun May 06, 2007 9:19 am Post subject: Winglets or modified winglets?

In a message dated 5/6/2007 12:01:48 A.M. Eastern Daylight Time,  pequeajim(at)gmail.com writes:

  	  Quote: 	
		     

Thanks for the info    Buz.  What do the winglets do for the top    end? 	


 

 Jim, 

     The answer to your question is "It all  depends".  Winglets seem to be a part of aviation design that is part  science and part magic - kind of like finding the right propeller for a  specific airplane (more on that later in another e-mail).  The idea behind  winglets is that, properly designed, they reduce the wingtip vortices, and thus  decreases overall drag.  What really happens is that the winglet is  designed to produce a vortex that is opposite to the wing vortex and  thus cancel out each other (therefore less overall drag).  There  is also a somewhat effective span increase when using winglets - so you in  effect you have a longer wing without the increased drag penalty.   Therefore, you can sometimes get two drag reductions by using winglets.   Burt Rutan has used them effectively on several of his designs as well as some  of the more modern "super gliders" use them to great effect.  The real key  to any improvement totally depends on how they are designed.  The obvious  questions are: how large to make them and at what angle should they be  installed?  Throw in the question of the specific airfoil shape on the  winglet and you start to see just how much science and magic is involved.   I am sure that most winglets you are starting to see on experimental aircraft  are just there to make the design look more modern with probably not much  overall effect of drag reduction.  In fact, if they are not done correctly  they can have an adverse effect on the yaw stability of an airplane - not so  much making it more yaw unstable, but instead causing the opposite effect where  it takes much more rudder to yaw the airplane.  Bottom line, I really have  no clue as to how much winglets might do for top end on a Lightning.  They  will probably help, but until installed and flight tested how do we really  know.  The idea behind the tip extensions and possible winglets on the  Lightning will be to add wing area ant thus lower stall speed for those who want  to have it meet light sport requirements.  Any increase in top end will  also result in more efficient cruise numbers as far a fuel burn.  Should be  a win-win situation.  You can bet that the Lightning team will do it right  if they do it at all.  I am that confident in the way they do things.   

 Blue Skies,

 Buz



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  [quote][b]

pequeajim

Joined: 03 Sep 2006
Posts: 708
Location: New Holland, PA

Posted: Sun May 06, 2007 2:31 pm Post subject: Winglets or modified winglets?

Buz:  

   

I believe the tips on the Lightning are regular tips with a rounded edge?  Has Arion considered Horner tips?  I’m not suggesting those, but they are very common with the Murphy aircraft and my Rebel lowered stall by a few mph, and increased the top end by 1 or 2.  When you’re flying at 100-110mph, that’s a lot.  They effectively increase the wingspan by a similar effect as the winglets that we were talking about.   

   

With a quick Google, there seems to be quite a bit of information on the subject relating to the Van’s kits.    

   

Looks like some late night reading to catch up on.  

   

Jim!  

N730AL  

         

  

From: owner-lightning-list-server(at)matronics.com [mailto:owner-lightning-list-server(at)matronics.com] On Behalf Of N1BZRich(at)aol.com

 Sent: Sunday, May 06, 2007 1:16 PM

 To: lightning-list(at)matronics.com

 Subject: Re: Lightning-List: Winglets or modified winglets?  

  

       

In a message dated 5/6/2007 12:01:48 A.M. Eastern Daylight Time, pequeajim(at)gmail.com writes:  

   	  Quote: 	
		    

Thanks for the info Buz.  What do the winglets do for the top end?  	
  

    

Jim,   

    

    The answer to your question is "It all depends".  Winglets seem to be a part of aviation design that is part science and part magic - kind of like finding the right propeller for a specific airplane (more on that later in another e-mail).  The idea behind winglets is that, properly designed, they reduce the wingtip vortices, and thus decreases overall drag.  What really happens is that the winglet is designed to produce a vortex that is opposite to the wing vortex and thus cancel out each other (therefore less overall drag).  There is also a somewhat effective span increase when using winglets - so you in effect you have a longer wing without the increased drag penalty.  Therefore, you can sometimes get two drag reductions by using winglets.  Burt Rutan has used them effectively on several of his designs as well as some of the more modern "super gliders" use them to great effect.  The real key to any improvement totally depends on how they are designed.  The obvious questions are: how large to make them and at what angle should they be installed?  Throw in the question of the specific airfoil shape on the winglet and you start to see just how much science and magic is involved.  I am sure that most winglets you are starting to see on experimental aircraft are just there to make the design look more modern with probably not much overall effect of drag reduction.  In fact, if they are not done correctly they can have an adverse effect on the yaw stability of an airplane - not so much making it more yaw unstable, but instead causing the opposite effect where it takes much more rudder to yaw the airplane.  Bottom line, I really have no clue as to how much winglets might do for top end on a Lightning.  They will probably help, but until installed and flight tested how do we really know.  The idea behind the tip extensions and possible winglets on the Lightning will be to add wing area ant thus lower stall speed for those who want to have it meet light sport requirements.  Any increase in top end will also result in more efficient cruise numbers as far a fuel burn.  Should be a win-win situation.  You can bet that the Lightning team will do it right if they do it at all.  I am that confident in the way they do things.    

    

Blue Skies,  

    

Buz  

  



 

         

  

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N1BZRich(at)AOL.COM
Guest

Posted: Sun May 06, 2007 5:04 pm Post subject: Winglets or modified winglets?

Jim,

 Yes, the current Lightning tips are the standard rounded type.  So far  they have not tried Hoerner tips.  As I understand it, Hoerner tips which  turn up (and droop tips which obviously turn down) attempt to reduce the  effect of wing tip vortices by "throwing" the vortex out further from the wing  thereby making the wing "think" it were a few inches longer.  The droop  tips do seem to help stall when in ground effect.  However, neither of  these would have enough effect on the Lightning wing (and the required reduction  in stall speed to meet LSA).  What will be needed for that requirement is  some additional wing area.  That additional area and some effective tips  are what they will be looking at.  And yes, there is lots of need for  studying all available information on the subject.  I feel confident the  Lightning team is already involved in that.

 Buz



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  [quote][b]

pequeajim

Joined: 03 Sep 2006
Posts: 708
Location: New Holland, PA

Posted: Sun May 06, 2007 6:04 pm Post subject: Winglets or modified winglets?

There is a very simple discussion by Chris Heinz of wing and wingtip design at the following link if anyone is interested…  

   

http://www.zenithair.com/stolch801/design/design.html  

   

   

Jim!  

         

  

From: owner-lightning-list-server(at)matronics.com [mailto:owner-lightning-list-server(at)matronics.com] On Behalf Of N1BZRich(at)aol.com

 Sent: Sunday, May 06, 2007 9:04 PM

 To: lightning-list(at)matronics.com

 Subject: Re: Lightning-List: Winglets or modified winglets?  

  

     

Jim,  

    

Yes, the current Lightning tips are the standard rounded type.  So far they have not tried Hoerner tips.  As I understand it, Hoerner tips which turn up (and droop tips which obviously turn down) attempt to reduce the effect of wing tip vortices by "throwing" the vortex out further from the wing thereby making the wing "think" it were a few inches longer.  The droop tips do seem to help stall when in ground effect.  However, neither of these would have enough effect on the Lightning wing (and the required reduction in stall speed to meet LSA).  What will be needed for that requirement is some additional wing area.  That additional area and some effective tips are what they will be looking at.  And yes, there is lots of need for studying all available information on the subject.  I feel confident the Lightning team is already involved in that.  

    

Buz  

  



 

         

  

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dashvii(at)hotmail.com
Guest

Posted: Sun May 06, 2007 7:07 pm Post subject: Winglets or modified winglets?

In all my reading on winglet design I have found that it is very much trial 

and error on the angle of attachment.  Thorough testing needs to be done in 

order to verify all performance data.  In addition it is going to effect the 

wings torsional properties.  Most current winglets are added to reduce fuel 

consumption by about 1-3%.  They aren't added as a way to increase speed, 

although it stands to reason with reduced drag you should get a byproduct of 

speed.  Also, from all the current stuff written on Horner tips, it all says 

that in cruising flight there is no difference in data obtained with regards 

to the Horner tips.



Current aircraft typically utilize a winglet of about 1/3 the height that 

they would need to be in order to see the potential they could gain.  The 

reason why they don't make them taller?  Looks.  It would look bad.  Also 

most winglets are a post production modification.  The increase in vertical 

surface area makes the plane too stable, which means you would need to 

decrease tail volume and/or increase rudder.  The most current aircraft are 

looking to utilize horizontal winglets, or raked tips like the 777 and 787 

have.  These keep from having to structurally reinforce the wingtip extra, 

keeps stability the same, but adds wing area while decreasing the wingtip 

vortices.



I'm not sure of any GA aircraft that has raked tips.  There's another kind 

of wingtip though.  The one like which was used on the Esqual wing like Buz 

has.  This looks almost like a little mini blended winglet (like SouthWest 

737's).  I'm not sure how much they would decrease tip vortices, but they 

would act as a wing endplate which would keep the airflow from traveling 

laterally across the wing (although that benefit would be more apparent with 

a highly swept wing than a straight wing).  The Airbus A-320 uses a wingtip 

fence, which is more like this end plating than a winglet.



The actual purpose of a winglet though isn't to reduce drag, it isn't to 

gain speed, it is "to add additional wing area without paying the drag 

penalty that would be associated with a typical extension."



The easiest thing to do would be something similar to the Esqual.

Brian W.



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pjdisher(at)bigpond.com
Guest

Posted: Mon May 07, 2007 12:37 am Post subject: Winglets or modified winglets?

Hi Buz,Nick & Brian,

  

 Earlier email failed now one picture only of our winglet sugestion for my  a/c.

  

 Its our effot to date and your thoughts on this design would be  appreciated. 

  

 Would somethink like this work?

  

 Regards,

  

 Peter Disher

 Hallidays Point

 Australia

 [quote]   ---

N1BZRich(at)AOL.COM
Guest

Posted: Mon May 07, 2007 7:26 pm Post subject: Winglets or modified winglets?

Hi Peter,

 The tip looks good, but until you try it, there is no way to know how it  might work.  I have no idea how you determine the various sizes and angles  to use, but what you have done certainly looka unique.  And it is  an impressive bit of fiberglass work with the compound curves and angles.   I have never seen anyone combine a droop tip with a winglet.  I have  seen the up turned Hoerner tips with winglets (I think they have started calling  them "blended tips") and they obviously work.  That way should be much  easier to construct. Be sure to let us know how your design works  out.  

 Blue Skies,

 Buz 



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  [quote][b]

lozhoffman(at)yahoo.com
Guest

Posted: Mon May 07, 2007 11:52 pm Post subject: Winglets or modified winglets?

Hi All,

I just sent an email to Peter saying the same as you

Buz before I read your post..I've never seen a

combination droop tip/winglet before and the idea is

fascinating.



Sailplanes have ben using winglets for many years now

and few current production models would not have them

fitted at the factory or as an option. Two later

versions of my motorglider that I share hangarage with

both have removeable winglets fitted.



This source of expereince and technology may not be as

removed from the Lightning application as one might

think, especially in terms of airspeed. Inter thermal

speeds of modern open class gliders (spans of over

15metres) are regularly in the range of 120-140mph and

often up to 170mph during final glide.



Sailplane manufacturers have already developed

winglets suited to Lightning speeds so would be a

source of aplicable info. 



Pilot reports are often non committal about large

performance gains but are consistent when it comes to

at least some gains. Dont know of any one removing

winglets once fitted or electing to never use

removable ones. Of course this may be something to do

with just how hot aircraft look with them fitted!



Laurie

Sydney

--- N1BZRich(at)aol.com wrote:



 	  Quote: 	
		   Hi Peter,

 The tip looks good, but until you try it, there is

 no way to know how it  

 might work.  I have no idea how you determine the

 various sizes and angles  to 

 use, but what you have done certainly looka unique. 

 And it is  an impressive 

 bit of fiberglass work with the compound curves and

 angles.   I have never seen 

 anyone combine a droop tip with a winglet.  I have 

 seen the up turned Hoerner 

 tips with winglets (I think they have started

 calling  them "blended tips") 

 and they obviously work.  That way should be much 

 easier to construct. Be sure 

 to let us know how your design works  out.  

 Blue Skies,

 Buz 

 

 

 

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