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

Slats & vgs

Matronics Email Lists Forum Index -> Zenith701801-List

View previous topic :: View next topic

Author Message

frank goodnight

Joined: 27 Dec 2011
Posts: 126

Posted: Mon Mar 18, 2013 9:52 am Post subject: Slats & vgs

Hi,

I haven't had my 701 long enough to know what I like , or dislike about it or 

what I want to put on it -- Fairings etc-- .Don't plan on doing anything to it anytime soon

just fly it until i get to know it good enough to know what if anything I want to change.

Right now it's stock with a 100 hp rotax.

  Having said that , it seems as if the people that have replaced the slats with VGs

are really happy with the change. as it is cheap and easy to do I may want to try it.

I would like to know what the change does to the cg? Are the slats considered to be part of the wing chord? where is the range without the slats.Does it move from where it was the the slats? May seem simple to some of you but it has me  somewhat confused.

Thanks for any thoughts you may have

Frank

Fayetteville ,AR

 



   

 [quote][b]

- The Matronics Zenith701801-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?Zenith701801-List

dougsnash

Joined: 14 Apr 2008
Posts: 281

Posted: Mon Mar 18, 2013 10:59 am Post subject: Slats & vgs

Frank, first off let me say that I am one of those stubborn 701 owners who feel that if I'd wanted a plane without slats, I would have built something other than a 701.



According to Chris Heintz (at an Oshkosh forum), the slats are part of the chord of the wing.  The airfoil shape (I forget the number) includes the slat.  The airfoil without the slat is an "untested" airfoil which he never intended to be flown.  Chris further claimed that air is not supposed to be flowing through the slot unless the wing is at a fairly high angle of attack and thus should have minimal drag while in cruise.  Chris claimed slats are essentially the best high lift device that can be installed on this class of aircraft in a simple and light fashion.



All of Chris's statements aside, it is undeniable that many 701 owners have  chosen to remove their slats and install VGs and have seen a 5-10 MPH increase in cruise speed.  I suspect the removal of the slat has reduced the effective chord of the wing and thus increased the aspect ratio of the wing.  Therefore, a 701 minus the slats essentially has a smaller wing than one with slats.  Smaller wing equals less drag equals more speed.  Problem is, the wing sans slat looses much of its STOL capability.  When you add the VGs, you recover much (not quite all) of the lost STOL capability.  The increased speed of a 701 with VGs instead of slats does not come from the VGs, it comes from the removal of wing area, weight, and drag.  The VGs are only a band-aid to repair the STOL capabilities lost by removal of the slats.



As for the changes to the CofG with the slats removed, the slats are fairly close to the CofG of the plane so their removal should have minimal effect.  Since the center of  lift theoretically moves aft when the slats are removed at the same time as the Cof G moves aft, the total change to how the plane responds is supposedly very little.  Thus, you get the typical response from 701 owners who elect to remove their slats saying they notice very little negative effect and the big positive effect of the increased speed or economy (depending on how you choose to fly).



I am trying to present as balanced a point of view here as I can.  As I've stated, I have no intention of removing my slats.  I can understand the urge to remove slats though given the potential increase in speed for negligible negative side effect.  John Gilpen (sp?) from Australia has done a bunch of flight testing and supposedly has an extensive website (www.stolspeed.com I think) documenting his experiences with 701s and Savannahs flying without slats.  While I have not looked at his site (as I don't plan on removing my slats)  many people claim it has great information.  One caveat to keep in mind is that JG sells VG kits for 701s and Savannahs so view his information with a critical eye.  This being said, however, he seems to have many satisfied customers so you will have to decide for yourself.



I hope my little ramble about slats vs VGs has been of some use and I have provided the balanced opinion I was attempting to present.



Doug M

701 from scratch

NW Ontario, Canada

        From: frank goodnight <frank.goodnight(at)att.net>

 To: zenith701801-list(at)matronics.com 

 Sent:  Monday, March 18, 2013 12:52:11 PM

 Subject: Slats & vgs

  

 

Hi,

I haven't had my 701 long enough to know what I like , or dislike about it or 

what I want to put on it -- Fairings etc-- .Don't plan on doing anything to it anytime soon

just fly it until i get to know it good enough to know what if anything I want to change.

Right now it's stock with a 100 hp rotax.

  Having said that , it seems as if the people that have replaced the slats with VGs

are really happy with the change. as it is cheap and easy to do I may want to try it.

I would like to know what the change does to the cg? Are the slats  considered to be part of the wing chord? where is the range without the slats.Does it move from where it was the the slats? May seem simple to some of you but it has me  somewhat confused.

Thanks for any thoughts you may have

Frank

Fayetteville ,AR



 





 

  

 [quote][b]

- The Matronics Zenith701801-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?Zenith701801-List

roger(at)nwtradingpost.co
Guest

Posted: Mon Mar 18, 2013 11:20 am Post subject: Slats & vgs

Doug

 

Thanks, this is the best (and most balanced!) discourse that I have seen on this perennially occurring topic

 

Like you I do no t plan on removing the slats but I have added vg’s to the elevator as suggested by Zenith (yes, there is a place for vg’s on the 701!)

 

Roger

 

From: owner-zenith701801-list-server(at)matronics.com [mailto:owner-zenith701801-list-server(at)matronics.com] On Behalf Of MacDonald Doug

Sent: Monday, March 18, 2013 11:59 AM

To: zenith701801-list(at)matronics.com

Subject: Re: Slats & vgs

 

Frank, first off let me say that I am one of those stubborn 701 owners who feel that if I'd wanted a plane without slats, I would have built something other than a 701.



According to Chris Heintz (at an Oshkosh forum), the slats are part of the chord of the wing.  The airfoil shape (I forget the number) includes the slat.  The airfoil without the slat is an "untested" airfoil which he never intended to be flown.  Chris further claimed that air is not supposed to be flowing through the slot unless the wing is at a fairly high angle of attack and thus should have minimal drag while in cruise.  Chris claimed slats are essentially the best high lift device that can be installed on this class of aircraft in a simple and light fashion.



All of Chris's statements aside, it is undeniable that many 701 owners have chosen to remove their slats and install VGs and have seen a 5-10 MPH increase in cruise speed.  I suspect the removal of the slat has reduced the effective chord of the wing and thus increased the aspect ratio of the wing.  Therefore, a 701 minus the slats essentially has a smaller wing than one with slats.  Smaller wing equals less drag equals more speed.  Problem is, the wing sans slat looses much of its STOL capability.  When you add the VGs, you recover much (not quite all) of the lost STOL capability.  The increased speed of a 701 with VGs instead of slats does not come from the VGs, it comes from the removal of wing area, weight, and drag.  The VGs are only a band-aid to repair the STOL capabilities lost by removal of the slats.



As for the changes to the CofG with the slats removed, the slats are fairly close to the CofG of the plane so their removal should have minimal effect.  Since the center of lift theoretically moves aft when the slats are removed at the same time as the Cof G moves aft, the total change to how the plane responds is supposedly very little.  Thus, you get the typical response from 701 owners who elect to remove their slats saying they notice very little negative effect and the big positive effect of the increased speed or economy (depending on how you choose to fly).



I am trying to present as balanced a point of view here as I can.  As I've stated, I have no intention of removing my slats.  I can understand the urge to remove slats though given the potential increase in speed for negligible negative side effect.  John Gilpen (sp?) from Australia has done a bunch of flight testing and supposedly has an extensive website (www.stolspeed.com I think) documenting his experiences with 701s and Savannahs flying without slats.  While I have not looked at his site (as I don't plan on removing my slats) many people claim it has great information.  One caveat to keep in mind is that JG sells VG kits for 701s and Savannahs so view his information with a critical eye.  This being said, however, he seems to have many satisfied customers so you will have to decide for yourself.



I hope my little ramble about slats vs VGs has been of some use and I have provided the balanced opinion I was attempting to present.



Doug M

701 from scratch

NW Ontario, Canada

 

From: frank goodnight <frank.goodnight(at)att.net (frank.goodnight(at)att.net)>

To: zenith701801-list(at)matronics.com (zenith701801-list(at)matronics.com) 

Sent: Monday, March 18, 2013 12:52:11 PM

Subject: Slats & vgs



 

Hi,



I haven't had my 701 long enough to know what I like , or dislike about it or 



what I want to put on it -- Fairings etc-- .Don't plan on doing anything to it anytime soon



just fly it until i get to know it good enough to know what if anything I want to change.



Right now it's stock with a 100 hp rotax.



  Having said that , it seems as if the people that have replaced the slats with VGs



are really happy with the change. as it is cheap and easy to do I may want to try it.



I would like to know what the change does to the cg? Are the slats considered to be part of the wing chord? where is the range without the slats.Does it move from where it was the the slats? May seem simple to some of you but it has me somewhat confused.



Thanks for any thoughts you may have



Frank



Fayetteville ,AR



 



 

 	  Quote: 	
		    http://www.matronics.com/Navigator?Zenith701801-List 	
0 	  Quote: 	
		   	
1 	  Quote: 	
		   	
2 	  Quote: 	
		   	
3 	  Quote: 	
		   	
4 	  Quote: 	
		   	
5 	  Quote: 	
		   	
6 	  Quote: 	
		   	
7 	  Quote: 	
		   	
8

   [quote][b]

- The Matronics Zenith701801-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?Zenith701801-List

frank goodnight

Joined: 27 Dec 2011
Posts: 126

Posted: Mon Mar 18, 2013 3:09 pm Post subject: Slats & vgs

Hi Doug,

Thanks for your answer. Hope I get a couple from people that have replaced the 

slats to tell how things go. 

Frank

do not archive

From: MacDonald Doug <dougsnash(at)yahoo.com>

To: "zenith701801-list(at)matronics.com" <zenith701801-list(at)matronics.com>

Sent: Mon, March  18, 2013 1:59:42 PM

Subject: Re: Slats & vgs



 Frank, first off let me say that I am one of those stubborn 701 owners who feel that if I'd wanted a plane without slats, I would have built something other than a 701.



According to Chris Heintz (at an Oshkosh forum), the slats are part of the chord of the wing.  The airfoil shape (I forget the number) includes the slat.  The airfoil without the slat is an "untested" airfoil which he never intended to be flown.  Chris further claimed that air is not supposed to be flowing through the slot unless the wing is at a fairly high angle of attack and thus should have minimal drag while in cruise.  Chris claimed slats are essentially the best high lift device that can be installed on this class of aircraft in a simple and light fashion.



All of Chris's statements aside, it is undeniable that many 701 owners have  chosen to remove their slats and install VGs and have seen a 5-10 MPH increase in cruise speed.  I suspect the removal of the slat has reduced the effective chord of the wing and thus increased the aspect ratio of the wing.  Therefore, a 701 minus the slats essentially has a smaller wing than one with slats.  Smaller wing equals less drag equals more speed.  Problem is, the wing sans slat looses much of its STOL capability.  When you add the VGs, you recover much (not quite all) of the lost STOL capability.  The increased speed of a 701 with VGs instead of slats does not come from the VGs, it comes from the removal of wing area, weight, and drag.  The VGs are only a band-aid to repair the STOL capabilities lost by removal of the slats.



As for the changes to the CofG with the slats removed, the slats are fairly close to the CofG of the plane so their removal should have minimal effect.  Since the center of  lift theoretically moves aft when the slats are removed at the same time as the Cof G moves aft, the total change to how the plane responds is supposedly very little.  Thus, you get the typical response from 701 owners who elect to remove their slats saying they notice very little negative effect and the big positive effect of the increased speed or economy (depending on how you choose to fly).



I am trying to present as balanced a point of view here as I can.  As I've stated, I have no intention of removing my slats.  I can understand the urge to remove slats though given the potential increase in speed for negligible negative side effect.  John Gilpen (sp?) from Australia has done a bunch of flight testing and supposedly has an extensive website (www.stolspeed.com I think) documenting his experiences with 701s and Savannahs flying without slats.  While I have  not looked at his site (as I don't plan on removing my slats)  many people claim it has great information.  One caveat to keep in mind is that JG sells VG kits for 701s and Savannahs so view his information with a critical eye.  This being said, however, he seems to have many satisfied customers so you will have to decide for yourself.



I hope my little ramble about slats vs VGs has been of some use and I have provided the balanced opinion I was attempting to present.



Doug M

701 from scratch

NW Ontario, Canada

        From: frank goodnight <frank.goodnight(at)att.net>

 To: zenith701801-list(at)matronics.com 

 Sent:  Monday, March 18, 2013 12:52:11 PM

 Subject: Slats & vgs

  

 

Hi,

I haven't had my 701 long enough to know what I like , or dislike about it or 

what I want to put on it -- Fairings etc-- .Don't plan on doing anything to it anytime soon

just fly it until i get to know it good enough to know what if anything I want to change.

Right now it's stock with a 100 hp rotax.

  Having said that , it seems as if the people that have replaced the slats with VGs

are really happy with the change. as it is cheap and easy to do I may want to try it.

I would like to know what the change does to the cg? Are the slats  considered to be part of the wing chord? where is the range without the slats.Does it move from where it was the the slats? May seem simple to some of you but it has me  somewhat confused.

Thanks for any thoughts you may have

Frank

Fayetteville ,AR



 





 

  

  	  Quote: 	
		  

	


   

 [quote][b]

- The Matronics Zenith701801-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?Zenith701801-List

ronlee

Joined: 25 Dec 2006
Posts: 141

Posted: Tue Mar 26, 2013 12:05 pm Post subject: Re: Slats & vgs

I personally have removed the slats from my 701 and would rather fly without them for at least two reasons.  

#1 it is easier to land.

#2 it is easier to take off.

I have VG's from John Gilpin. If you order from him you will receive them with full instructions for proper installation.

In the air you will not notice any difference, increase in speed, not enough to talk about.

One more thing, With slats you will command lots of attention and get lots of questions. Without them nothing special so no questions or curiosity about the plane. In other words slats are a great attention generator and I believe a great sales tool. Mine are sitting on a shelf and will include them someday when I sell my 701.

- The Matronics Zenith701801-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?Zenith701801-List

_________________
Ron Lee
Tucson, Arizona

Display posts from previous:

	Matronics Email Lists Forum Index -> Zenith701801-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