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Flap Seals

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fklein(at)orcasonline.com
Guest

Posted: Sun May 06, 2007 9:28 am Post subject: Flap Seals

 	  Quote: 	
		    John mentioned how sealing up the aircraft would clean up the lines, 

 resulting in better speeds.  I decided to add some gap seals to the 

 wing, to seal the flaps, upon retraction.  What I used was a 2.25" 

 wide piece of .020" styrene, a product that I use, almost daily in my 

 sign/graphics business.  I attached it to the wing using 1" hem tape 

 (a very strong, two sided tape, used to hem banners).


	


Hey Jeff...



I've also had email exchanges w/ John Lawton and have perused a site he 

recommended for info on gap seals...all very interesting. Could you go 

into a little more detail on the nature of your installation? Exactly 

where and in what plane have you attached this styrene? Does it create 

a pressure seal?. In what way does it alter the airflow?



Fred

A194



working on cockpit module (finally!)

topglock(at)cox.net
Guest

Posted: Sun May 06, 2007 12:30 pm Post subject: Flap Seals

Fred,

I took some pics, but haven't had a chance to post them.  The process is 

dead simple, though.  I cut two pieces of styrene, 2.25" wide, the 

length of the flaps (about 63"), then added the hem tape to one edge.  

The tape is 1" wide, so I marked back 1" onto the wing and drew a line 

with a grease pen, parallel to the underside of the wing edge.  I then 

notched the styrene, where it had to clear the flap hinges, removed the 

backing tape from the hem tape and applied the strip to the wing.  The 

width was such that it covered the gap, spilling over onto the flaps.  

It is not truly a pressure seal, but is sufficient to direct the air 

under the flap and not up, into the closeout.  My guess is that it also 

deflects the air, under the flaps, even with the flaps deployed, as 

there is a definite lack of drag.  If you do this mod, be prepared to 

re-learn your approaches and it wouldn't hurt to have a good bit of 

runway on the first few attempts...

Jeff - Baby Blue

Fred Klein wrote:

 	  Quote: 	

>  John mentioned how sealing up the aircraft would clean up the lines, 

> resulting in better speeds.  I decided to add some gap seals to the 

> wing, to seal the flaps, upon retraction.  What I used was a 2.25" 

> wide piece of .020" styrene, a product that I use, almost daily in my 

> sign/graphics business.  I attached it to the wing using 1" hem tape 

> (a very strong, two sided tape, used to hem banners).

 Hey Jeff...

 I've also had email exchanges w/ John Lawton and have perused a site 

 he recommended for info on gap seals...all very interesting. Could you 

 go into a little more detail on the nature of your installation? 

 Exactly where and in what plane have you attached this styrene? Does 

 it create a pressure seal?. In what way does it alter the airflow?

 Fred

 A194

 working on cockpit module (finally!)

garrys(at)tampabay.rr.com
Guest

Posted: Sun May 06, 2007 1:07 pm Post subject: Flap Seals

Jeff, did you think about applying gap seals to the ailerons?  Any reason to 

do just the flaps?



Garry

---

96victor(at)gmail.com
Guest

Posted: Sun May 06, 2007 3:14 pm Post subject: Flap Seals

Thanks Jeff

 Is the hemtape "Orabond?'

 Is the styrene available at sign makers?

 Don't some of the glider guys use mylar for seals/

 Tom

 On 5/6/07, Rman <topglock(at)cox.net (topglock(at)cox.net)> wrote: [quote]--> Europa-List message posted by: Rman <topglock(at)cox.net (topglock(at)cox.net)>

Fred,

I took some pics, but haven't had a chance to post them.  The process is

dead simple, though.  I cut two pieces of styrene, 2.25" wide, the

length of the flaps (about 63"), then added the hem tape to one edge. 

The tape is 1" wide, so I marked back 1" onto the wing and drew a line

with a grease pen, parallel to the underside of the wing edge.  I then

notched the styrene, where it had to clear the flap hinges, removed the 

backing tape from the hem tape and applied the strip to the wing.  The

width was such that it covered the gap, spilling over onto the flaps.

It is not truly a pressure seal, but is sufficient to direct the air

 under the flap and not up, into the closeout.  My guess is that it also

deflects the air, under the flaps, even with the flaps deployed, as

there is a definite lack of drag.  If you do this mod, be prepared to

re-learn your approaches and it wouldn't hurt to have a good bit of 

runway on the first few attempts...

Jeff - Baby Blue

Fred Klein wrote:

 	  Quote: 	
		   --> Europa-List message posted by: Fred Klein <fklein(at)orcasonline.com (fklein(at)orcasonline.com)>

 >

[quote]

>  John mentioned how sealing up the aircraft would clean up the lines,

> resulting in better speeds.  I decided to add some gap seals to the

> wing, to seal the flaps, upon retraction.  What I used was a  2.25"

> wide piece of .020" styrene, a product that I use, almost daily in my

> sign/graphics business.  I attached it to the wing using 1" hem tape

> (a very strong, two sided tape, used to hem banners). 

 Hey Jeff...

 I've also had email exchanges w/ John Lawton and have perused a site

 he recommended for info on gap seals...all very interesting. Could you

 go into a little more detail on the nature of your installation? 

 Exactly where and in what plane have you attached this styrene? Does

 it create a pressure seal?. In what way does it alter the airflow?

 Fred

 A194

 working on cockpit module (finally!)  [quote][b]

daseitz(at)cfl.rr.com
Guest

Posted: Sun May 06, 2007 3:49 pm Post subject: Flap Seals

The flaps on the Europa are Slotted Flaps.  They are designed to let the air

go thru the slot from the bottom to the top of the flap. The next step up is

the Fowler Flap design.



Dean Seitz

fklein(at)orcasonline.com
Guest

Posted: Sun May 06, 2007 4:19 pm Post subject: Flap Seals

On Sunday, May 6, 2007, at 01:29  PM, Rman wrote:



 	  Quote: 	
		   



  It has also resulted in more float, during landing, which I attribute 

 to reduced stall speeds.  I say reduced stall speeds, because, by 

 reducing my final approach from 65 kph to 60 kph, across the numbers, 

 Baby Blue lands like she used to.



 It is not truly a pressure seal, but is sufficient to direct the air 

 under the flap and not up, into the closeout.  My guess is that it 

 also deflects the air, under the flaps, even with the flaps deployed, 

 as there is a definite lack of drag.  If you do this mod, be prepared 

 to re-learn your approaches and it wouldn't hurt to have a good bit of 

 runway on the first few attempts...


	


Jeff...Thanks for your very clear explanation of your installation.



There are no doubt folks on this list w/ more knowledge of aerodynamics 

than I, but I believe that the Europa flap design is such that when 

deployed, some portion of the increased lift is the result of air 

flowing over the top of the flap as the flap drops and moves to the 

rear when deployed.



Of course even when the flap is retracted, some air will find its way 

up thru the gap between the leading edge of the flap and the vertical 

face of the wing closeout, and it is this airflow which one wants to 

eliminate in order to enhance cruise efficiency.



If this is so, it would seem that another way to get this increase in 

cruise efficiency might be to install a compressible strip which would 

close the gap when flaps are retracted but allow airflow over the flaps 

when they are deployed, thus maintaining the short field 

characteristics of the aircraft which, if I understand you correctly, 

have been changed.



Keep us posted on your testing,



Fred

tonyk(at)kaon.co.nz
Guest

Posted: Sun May 06, 2007 4:47 pm Post subject: Flap Seals

 	  Quote: 	
		  > 

Of course even when the flap is retracted, some air will find its way 
	


up thru the gap between the leading edge of the flap and the vertical 

face of the wing closeout, and it is this airflow which one wants to 

eliminate in order to enhance cruise efficiency.



If this is so, it would seem that another way to get this increase in 

cruise efficiency might be to install a compressible strip which would 

close the gap when flaps are retracted but allow airflow over the flaps 

when they are deployed, thus maintaining the short field 

characteristics of the aircraft which, if I understand you correctly, 

have been changed. <<



Adding compressible strips in the flap closeout was suggested to me some

time ago by a person with many years of aeronautical design experience. 



The key is to close the airflow from lower to upper surface during

cruise but to ensure that the lower to upper airflow over the flap

remains per the design spec when the flaps are down.



This is quite easy to achieve by adding some light doorstop strip into

the flap closeout and, in many cases, will have already been achieved on

the port side if the pitot/static lines were run in the flap closout as

part of a retrofit.



Tony

topglock(at)cox.net
Guest

Posted: Sun May 06, 2007 7:13 pm Post subject: Flap Seals

Tom Friedland wrote:  	  Quote: 	
		     Thanks Jeff

    

   Is the hemtape "Orabond?'

 	
 Yes.  Very strong stuff...

  	  Quote: 	
		      

   Is the styrene available at sign makers?

 	
 Usually from a supplier, but some, such as myself will have some in stock...

  	  Quote: 	
		      

   Don't some of the glider guys use mylar for seals/

 	
 I believe they do...

 [quote]    

   Tom

   

  

   On 5/6/07, Rman <topglock(at)cox.net (topglock(at)cox.net)> wrote:    	  Quote: 	
		  --> Europa-List message posted by: Rman <topglock(at)cox.net (topglock(at)cox.net)>

     

 Fred,

     

 I took some pics, but haven't had a chance to post them.  The process is

 dead simple, though.  I cut two pieces of styrene, 2.25" wide, the

 length of the flaps (about 63"), then added the hem tape to one edge.     

 The tape is 1" wide, so I marked back 1" onto the wing and drew a line

 with a grease pen, parallel to the underside of the wing edge.  I then

 notched the styrene, where it had to clear the flap hinges, removed the     

 backing tape from the hem tape and applied the strip to the wing.  The

 width was such that it covered the gap, spilling over onto the flaps.

 It is not truly a pressure seal, but is sufficient to direct the air

 under the flap and not up, into the closeout.  My guess is that it also

 deflects the air, under the flaps, even with the flaps deployed, as

 there is a definite lack of drag.  If you do this mod, be prepared to

 re-learn your approaches and it wouldn't hurt to have a good bit of     

 runway on the first few attempts...

     

 Jeff - Baby Blue

     

 Fred Klein wrote:

 > --> Europa-List message posted by: Fred Klein <fklein(at)orcasonline.com (fklein(at)orcasonline.com)>

 >

 >

 >>  John mentioned how sealing up the aircraft would clean up the lines,

 >> resulting in better speeds.  I decided to add some gap seals to the

 >> wing, to seal the flaps, upon retraction.  What I used was a 2.25"

 >> wide piece of .020" styrene, a product that I use, almost daily in my

 >> sign/graphics business.  I attached it to the wing using 1" hem tape

 >> (a very strong, two sided tape, used to hem banners).     

 >

 > Hey Jeff...

 >

 > I've also had email exchanges w/ John Lawton and have perused a site

 > he recommended for info on gap seals...all very interesting. Could you

 > go into a little more detail on the nature of your installation?     

 > Exactly where and in what plane have you attached this styrene? Does

 > it create a pressure seal?. In what way does it alter the airflow?

 >

 > Fred

 > A194

 >

 > working on cockpit module (finally!)      	  Quote: 	
		  





    	
   	
   

 [b]

topglock(at)cox.net
Guest

Posted: Sun May 06, 2007 7:15 pm Post subject: Flap Seals

I thought about it, but believe that the aileron is sufficiently 

recessed to negate the need.  My opinion, of course.  I also considered 

the compressible seal, but did not have any around the shop.  Might 

still try it out, as replacing the styrene would be easy and cheap, 

should I decide to return to that...



Jeff



Garry wrote:

[quote] 



 Jeff, did you think about applying gap seals to the ailerons?  Any 

 reason to do just the flaps?



 Garry

 ---

william(at)wrmills.plus.c
Guest

Posted: Mon May 07, 2007 12:11 am Post subject: Flap Seals

If anyone in the UK finds a suitable lightweight compressible strip, please 

let us know the source and the material spec.

The ailerons can be sealed by flexible adhesive tape placed over the 

underside gap along the hinge line with the aileron in the full up position 

(so as not to restrict any movement).

Regards,

William

---

wdaniell(at)etb.net.co
Guest

Posted: Mon May 07, 2007 1:56 am Post subject: Flap Seals

Hmmm that would have been my question too.  My understanding was that the

flaps were designed to ensure flow up through the gap.  Perhaps someone can

shed light on this.

Will



--

willie.harrison(at)tinyon
Guest

Posted: Mon May 07, 2007 3:19 am Post subject: Flap Seals

Presumably, UK aircraft couldn't have this mod without the blessing  

of the PFA??

On 7 May 2007, at 10:55, William Daniell wrote:



[quote] 

 <wdaniell(at)etb.net.co>



 Hmmm that would have been my question too.  My understanding was  

 that the

 flaps were designed to ensure flow up through the gap.  Perhaps  

 someone can

 shed light on this.

 Will



 --

rogerabc

Joined: 19 Oct 2006
Posts: 11

Posted: Mon May 07, 2007 11:37 am Post subject: Flap Seals

This appears to fit the bill:



http://www.lasaero.com/las/30?part=DTD5531-60



10mm very soft silicone P seal which compresses easily to 3mm



They sent me a sample but I haven't bought the full length yet.



Cheers,

Roger

On 7 May 2007, at 09:09, William Mills wrote:



[quote] 

 <william(at)wrmills.plus.com>



 If anyone in the UK finds a suitable lightweight compressible  

 strip, please let us know the source and the material spec.

 The ailerons can be sealed by flexible adhesive tape placed over  

 the underside gap along the hinge line with the aileron in the full  

 up position (so as not to restrict any movement).

 Regards,

 William

 ---

ami(at)mcfadyean.freeserv
Guest

Posted: Mon May 07, 2007 12:12 pm Post subject: Flap Seals

Roger,

Could you double-confirm please that the 10mm dimension is the thickness 

prior to compression, or the width.



Duncan McF.

do not archive

---

fklein(at)orcasonline.com
Guest

Posted: Mon May 07, 2007 2:17 pm Post subject: Flap Seals

If this seal is suitable, it would appear that it would stop airflow 

thru flap gap when flaps are both deployed and retracted.

Is it then incorrect to believe that air flowing thru the gap w/ flaps 

deployed is desireable for max. lift?



Fred

A194



On Monday, May 7, 2007, at 12:35  PM, Roger Sheridan wrote:



 	  Quote: 	
		   

 <rogerjohnsheridan(at)yahoo.co.uk>



 This appears to fit the bill:



 http://www.lasaero.com/las/30?part=DTD5531-60



 10mm very soft silicone P seal which compresses easily to 3mm



 They sent me a sample but I haven't bought the full length yet.



 Cheers,

 Roger

>>


	


 	  Quote: 	
		  >> The key is to close the airflow from lower to upper surface during

>> cruise but to ensure that the lower to upper airflow over the flap

>> remains per the design spec when the flaps are down.

>>

>> Tony

rogerabc

Joined: 19 Oct 2006
Posts: 11

Posted: Mon May 07, 2007 11:14 pm Post subject: Flap Seals

It's the diameter of the circular section of the P & hence the  

thickness.



On 7 May 2007, at 21:11, Duncan & Ami McFadyean wrote:



[quote] 

 <ami(at)mcfadyean.freeserve.co.uk>



 Roger,

 Could you double-confirm please that the 10mm dimension is the  

 thickness prior to compression, or the width.



 Duncan McF.

 do not archive

 ---

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