Today's Message Index:
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1. 02:00 AM - Re: Europa-List Digest: 2 Msgs - 08/04/12 (C DREWETT)
2. 02:13 AM - Re: seals for control surfaces (craig)
3. 02:51 AM - Re: seals for control surfaces (GRAHAM SINGLETON)
4. 04:03 AM - Re: seals for control surfaces (GRAHAM SINGLETON)
5. 06:10 AM - Re: Re: Europa-List Digest: 2 Msgs - 08/04/12 (klinefelter.kevin@gmail.com)
Message 1
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| Subject: | Re: Europa-List Digest: 2 Msgs - 08/04/12 |
please de-list me=0AChris Drewett=0A=0A=0A________________________________
=0A From: Europa-List Digest Server <europa-list@matronics.com>=0ATo: Europ
a-List Digest List <europa-list-digest@matronics.com> =0ASent: Sunday, 5 Au
gust 2012, 8:01=0ASubject: Europa-List Digest: 2 Msgs - 08/04/12=0A =0A*=0A
=0A========================
==0A- Online Versions of Today's List Digest Archive=0A=====
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omplete Europa-List Digest can also be found in either of the =0Atwo Web Li
nks listed below.- The .html file includes the Digest formatted =0Ain HTM
L for viewing with a web browser and features Hyperlinked Indexes =0Aand Me
ssage Navigation.- The .txt file includes the plain ASCII version =0Aof t
he Europa-List Digest and can be viewed with a generic text editor =0Asuch
as Notepad or with a web browser. =0A=0AHTML Version:=0A=0A- - http://w
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2012-08-04&Archive=Europa=0A=0AText Version:=0A=0A- - http://www.matr
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-List Digest Archive=0A- - - - - - - - - - - - -
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l Messages Posted Sat 08/04/12: 2=0A- - - - - ------------------
----------------------------------------=0A=0A=0AToday's Message Index:=0A-
---------------------=0A=0A- - 1. 10:06 AM - seals for control surface
s- (Fred Klein)=0A- - 2. 10:52 AM - Re: seals for control surfaces
- (Robert Borger)=0A=0A=0A=0A________________________________- Message
1- _____________________________________=0A=0A=0ATime: 10:06:37 AM PST US
=0AFrom: Fred Klein <fklein@orcasonline.com>=0ASubject: Europa-List: seals
for control surfaces=0A=0AApropos the recent thread on this topic, I found
an old posting by- =0AJohn Lawton which may be enlightening:=0A=0A> In a
message dated 5/9/2007 2:59:30 AM Eastern Daylight Time, europa-list@matron
ics.com=0A=0A>- writes:=0A> My understanding is that preventing the air g
oing over the flap, in=0A> cruise, reduces drag, resulting in higher cruise
speed, which I have=0A> experienced.- I don't have the engineering backg
round to completely=0A> understand what is happening to the wing, in flight
.- That's why I=0A> depend on the guys on the list to keep me straight.
- I'm more of a- =0A> "try=0A> it and see" kinda guy... :)- John's ad
vice is based on the success- =0A> that=0A> the glider guys have had, sea
ling the gaps.- It seems to have worked- =0A> on=0A> Baby Blue, as well
.- Continued testing will tell to what degree of=0A> advantage the seals
make.- It may very well prove that the extra few=0A> knots is not worth t
he float upon landing.- I won't know until I- =0A> satisfy=0A> myself t
hat I've explored all the angles (and strip widths)... ;)=0A>=0A> Hey Jeff,
et al,=0A>=0A> The concept behind seals is pretty simple. In flight the wi
ng- =0A> creates a low pressure area on the top and high pressure on the
- =0A> bottom. (Bernoulli at it again) This pressure differential will tr
y- =0A> to equalize through the gap in the flap area and the hinge line o
f- =0A> the ailerons. This is also true to some extent on the rudder hing
e- =0A> line and the trim tabs when they are deflected. This equalization
- =0A> causes drag, a lot of drag. So, the idea behind seals, both flap g
ap- =0A> and positive seals on ailerons (and rudder and trim tabs), is to
- =0A> prevent this pressure equalization.=0A>=0A> On N245E I used PVC we
ather-strip to create the flap gap seal. The- =0A> size will depend on ho
w big your gap is between the leading edge of- =0A> the flap and the flap
closeout when retracted. Choose a foam that is- =0A> slightly thicker th
an the widest spot in the gap you have. The XS- =0A> flap closeout looks
as if it were designed to be sealed, given the- =0A> flat area at the bot
tom rear of the closeout. If you apply the foam- =0A> strip to the area w
here the flap "noses" into the closeout when up- =0A> it will seal this a
rea for cruise flight, but still allow air to- =0A> flow over the flap wh
en extended. Use a foam that crushes easily- =0A> when the flap comes in
contact with it. You don't want to use a foam- =0A> that is too stiff or
too thick or else your flaps won't fully- =0A> retract. PVC weather-strip
is soft and pliable and works quite well.- =0A> It is also fairly UV res
istant and is very cheap. It's available at- =0A> any hardware store in v
arious thicknesses. We've found that open- =0A> cell foams tend to not la
st very long due to UV and they don't seal- =0A> as well as closed cell f
oams like PVC. I also used weather-strip on- =0A> the ends of my flaps so
that they seal against the side of the- =0A> fuselage when they are in t
he up position. According to Bruce- =0A> Carmichael, renowned Aerodynamic
ist who wrote a book on drag- =0A> reduction in homebuilts, the wing root
/fuselage junction is another- =0A> area of high drag on most airplanes.
Sealing it up helps, too.=0A>=0A> Aileron seals are a bit more tricky to em
ploy. Some folks apply- =0A> Mylar strips over the hinge lines and think
they've sealed their- =0A> ailerons. This is not true. Mylar is not a sea
l, but rather is- =0A> applied to help the boundary flow stay attached ov
er the hinge line.- =0A> Mylar is also somewhat cosmetic in that it hides
the hinge line. At- =0A> high speeds the Mylar will lift up off the wing
due to the pressure- =0A> equalization, thus negating the effects of any
sealing the Mylar- =0A> might be offering. In some cases the Mylar will
"buzz" at high speeds.=0A>=0A> For sealing ailerons you need to install wha
t are known as positive- =0A> seals. These seals go from the leading edge
of the aileron to the- =0A> rear of the closeout. There are commercially
available materials for- =0A> this, including various types of cloth and
Teflon tapes. Some folks- =0A> even use cloth tape along the length of t
he aileron on the- =0A> undersurface. This is fine on low speed gliders,
but I think at the- =0A> speeds we fly this method likely creates more dr
ag. Personally, I- =0A> like parachute cloth for making positive seals. W
hatever you use it- =0A> needs to be zero porosity, i.e., allowing no air
flow through the- =0A> material. Parachute cloth is thin, flexible, zero
porosity and fits- =0A> the bill here perfectly. Here at the 'Possum Werk
s we use Parachute- =0A> cloth almost exclusively to fabricate positive s
eals. (it also helps- =0A> that we have a parachute manufacturer a few mi
les down the road that- =0A> gives us their scraps)=0A>=0A> First remove
the aileron. Then, cut a strip of parachute cloth about- =0A> 3" wide exa
ctly the length of the aileron. The width you use might- =0A> take some t
rial and error to get it right. You don't want it so wide- =0A> the the m
aterial bunches up when the aileron is deflected. 2.5' to- =0A> 3" width
should work on most Europas. Then, yellow contact cement is- =0A> applied
to the leading edge of the aileron, the rear of the closeout- =0A> and t
he mating surfaces of the cloth. We use a brand of glue called- =0A> Plio
-bond. It's handy in that it comes in a small bottle with a- =0A> brush a
pplicator. 3M also makes good contact cement if you can find- =0A> it. Av
oid the water based stuff. It is crap.=0A>=0A> Scuff the area to be glued w
ith 180 to enhance the adhesion. Apply- =0A> the glue in a swath about 3/
8" wide to both the seal, the aileron- =0A> and closeout. Use masking tap
e to keep your glue line to the- =0A> prescribed width and remove the tap
e once the glue is dry.- You can- =0A> also use the masking tape to pro
vide a guide when you scuff the area- =0A> to be glued, but wipe it with
acetone to remove dust before putting- =0A> the glue on. Allow the glue t
o dry, usually about 20 minutes, remove- =0A> the masking tape, then stic
k the seal to the leading edge of the- =0A> aileron first, preferably whi
le on your work bench. If you screw- =0A> something up Xylene will remove
the glue easily without harming your- =0A> paint. The next part takes an
extra set of hands.=0A>=0A> With one person holding the aileron close to t
he wing, attach the- =0A> other half of the cloth to the closeout forming
an "S" pattern.- =0A> Avoid wrinkles. See this drawing for details: http
://wingsandwheels.com/page28.htm=0A>=0A> Then, reattach the aileron as you
would normally do. Check the throw- =0A> and make sure you are not bindin
g! If you apply the seal correctly- =0A> you will not even know it is the
re. I have also sealed my rudder in- =0A> a similar fashion as well as th
e trim tabs. They create similar drag- =0A> when deflected.=0A>=0A> I can
't say specifically what improvements have occurred in N245E as- =0A> a r
esult of the seals since I've not ever flown it without them. I- =0A> can
tell you that I exceed Europas published numbers with a fixed- =0A> pitc
h prop. I can also tell you that on gliders we generally see 2- =0A> to 4
points increase in glide and a noticeable decrease in sink- =0A> rate, e
ven on the old "woodies", after the application of seals. In- =0A> power
planes this translates to faster cruise, better climb rates- =0A> and bet
ter fuel economy.=0A>=0A> Anyway, hope it helps!=0A>=0A> Regards,=0A>=0A> J
ohn Lawton=0A=0A________________________________- Message 2- __________
___________________________=0A=0A=0ATime: 10:52:40 AM PST US=0ASubject: Re:
Europa-List: seals for control surfaces=0AFrom: Robert Borger <rlborger@ma
c.com>=0A=0AFred,=0A=0AThanks for digging this up.- Very informative.-
Now, if I could just get =0Amy 914 running right=85=0A=0ABlue skies & tai
lwinds,=0ABob Borger=0AEuropa XS Tri, Rotax 914, Airmaster C/S Prop.=0ALitt
le Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP=0A3705 Lynchburg D
r.=0ACorinth, TX- 76208-5331=0ACel: 817-992-1117=0Arlborger@mac.com=0A=0A
On Aug 4, 2012, at 12:03 PM, Fred Klein <fklein@orcasonline.com> wrote:=0A
=0AApropos the recent thread on this topic, I found an old posting by John
=0ALawton which may be enlightening:=0A=0A> In a message dated 5/9/2007 2:5
9:30 AM Eastern Daylight Time, =0Aeuropa-list@matronics.com writes:=0A> My
understanding is that preventing the air going over the flap, in =0A> cruis
e, reduces drag, resulting in higher cruise speed, which I have =0A=0A> exp
erienced.- I don't have the engineering background to completely =0A> und
erstand what is happening to the wing, in flight.- That's why I =0A> depe
nd on the guys on the list to keep me straight.- I'm more of a =0A"try
=0A> it and see" kinda guy... :)- John's advice is based on the success
=0Athat =0A> the glider guys have had, sealing the gaps.- It seems to hav
e worked =0Aon =0A> Baby Blue, as well.- Continued testing will tell to w
hat degree of =0A> advantage the seals make.- It may very well prove that
the extra few =0A=0A> knots is not worth the float upon landing.- I won'
t know until I =0Asatisfy =0A> myself that I've explored all the angles (an
d strip widths)... ;)=0A>- =0A> Hey Jeff, et al,=0A>- =0A> The concept
behind seals is pretty simple. In flight the wing creates =0Aa low pressure
area on the top and high pressure on the bottom. =0A(Bernoulli at it again
) This pressure differential will try to equalize =0Athrough the gap in the
flap area and the hinge line of the ailerons. =0AThis is also true to some
extent on the rudder hinge line and the trim =0Atabs when they are deflect
ed. This equalization causes drag, a lot of =0Adrag. So, the idea behind se
als, both flap gap and positive seals on =0Aailerons (and rudder and trim t
abs), is to prevent this pressure =0Aequalization.=0A>- =0A> On N245E I u
sed PVC weather-strip to create the flap gap seal. The =0Asize will depend
on how big your gap is between the leading edge of the =0Aflap and the flap
closeout when retracted. Choose a foam that is =0Aslightly thicker than th
e widest spot in the gap you have. The XS flap =0Acloseout looks as if it w
ere designed to be sealed, given the flat area =0Aat the bottom rear of the
closeout. If you apply the foam strip to the =0Aarea where the flap "noses
" into the closeout when up it will seal this =0Aarea for cruise flight, bu
t still allow air to flow over the flap when =0Aextended. Use a foam that c
rushes easily when the flap comes in contact =0Awith it. You don't want to
use a foam that is too stiff or too thick or =0Aelse your flaps won't fully
retract. PVC weather-strip is soft and =0Apliable and works quite well. It
is also fairly UV resistant and is very =0Acheap. It's available at any ha
rdware store in various thicknesses. =0AWe've found that open cell foams te
nd to not last very long due to UV =0Aand they don't seal as well as closed
cell foams like PVC. I also used =0Aweather-strip on the ends of my flaps
so that they seal against the side =0Aof the fuselage when they are in the
up position. According to Bruce =0ACarmichael, renowned Aerodynamicist who
wrote a book on drag reduction =0Ain homebuilts, the wing root/fuselage jun
ction is another area of high =0Adrag on most airplanes. Sealing it up help
s, too.=0A>- =0A> Aileron seals are a bit more tricky to employ. Some fol
ks apply Mylar =0Astrips over the hinge lines and think they've sealed thei
r ailerons. =0AThis is not true. Mylar is not a seal, but rather is applied
to help the =0Aboundary flow stay attached over the hinge line. Mylar is a
lso somewhat =0Acosmetic in that it hides the hinge line. At high speeds th
e Mylar will =0Alift up off the wing due to the pressure equalization, thus
negating the =0Aeffects of any sealing the Mylar might be offering. In som
e cases the =0AMylar will "buzz" at high speeds.=0A>- =0A> For sealing ai
lerons you need to install what are known as positive =0Aseals. These seals
go from the leading edge of the aileron to the rear =0Aof the closeout. Th
ere are commercially available materials for this, =0Aincluding various typ
es of cloth and Teflon tapes. Some folks even use =0Acloth tape along the l
ength of the aileron on the undersurface. This is =0Afine on low speed glid
ers, but I think at the speeds we fly this method =0Alikely creates more dr
ag. Personally, I like parachute cloth for making =0Apositive seals. Whatev
er you use it needs to be zero porosity, i.e., =0Aallowing no airflow throu
gh the material. Parachute cloth is thin, =0Aflexible, zero porosity and fi
ts the bill here perfectly. Here at the =0A'Possum Werks we use Parachute c
loth almost exclusively to fabricate =0Apositive seals. (it also helps that
we have a parachute manufacturer a =0Afew miles down the road that gives u
s their scraps)=0A>- =0A> First remove the aileron. Then, cut a strip of
parachute cloth about =0A3" wide exactly the length of the aileron. The wid
th you use might take =0Asome trial and error to get it right. You don't wa
nt it so wide the the =0Amaterial bunches up when the aileron is deflected.
2.5' to 3" width =0Ashould work on most Europas. Then, yellow contact ceme
nt is applied to =0Athe leading edge of the aileron, the rear of the closeo
ut and the mating =0Asurfaces of the cloth. We use a brand of glue called P
lio-bond. It's =0Ahandy in that it comes in a small bottle with a brush app
licator. 3M =0Aalso makes good contact cement if you can find it. Avoid the
water based =0Astuff. It is crap.=0A>- =0A> Scuff the area to be glued w
ith 180 to enhance the adhesion. Apply the =0Aglue in a swath about 3/8" wi
de to both the seal, the aileron and =0Acloseout. Use masking tape to keep
your glue line to the prescribed =0Awidth and remove the tape once the glue
is dry.- You can also use the =0Amasking tape to provide a guide when yo
u scuff the area to be glued, but =0Awipe it with acetone to remove dust be
fore putting the glue on. Allow =0Athe glue to dry, usually about 20 minute
s, remove the masking tape, then =0Astick the seal to the leading edge of t
he aileron first, preferably =0Awhile on your work bench. If you screw some
thing up Xylene will remove =0Athe glue easily without harming your paint.
The next part takes an extra =0Aset of hands.=0A>- =0A> With one person h
olding the aileron close to the wing, attach the =0Aother half of the cloth
to the closeout forming an "S" pattern. Avoid =0Awrinkles. See this drawin
g for details: =0Ahttp://wingsandwheels.com/page28.htm=0A>- =0A> Then, re
attach the aileron as you would normally do. Check the throw =0Aand make su
re you are not binding! If you apply the seal correctly you =0Awill not eve
n know it is there. I have also sealed my rudder in a =0Asimilar fashion as
well as the trim tabs. They create similar drag when =0Adeflected.=0A>-
=0A> I can't say specifically what improvements have occurred in N245E as a
=0Aresult of the seals since I've not ever flown it without them. I can
=0Atell you that I exceed Europas published numbers with a fixed pitch =0Ap
rop. I can also tell you that on gliders we generally see 2 to 4 points =0A
increase in glide and a noticeable decrease in sink rate, even on the =0Aol
d "woodies", after the application of seals. In power planes this =0Atransl
ates to faster cruise, better climb rates and better fuel economy.=0A>-
=0A> Anyway, hope it helps!=0A> =0A> Regards,=0A>- =0A> John Lawton=0A=0A
==================
Message 2
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| Subject: | seals for control surfaces |
While the subject of seals has veered into the subject of Drag, has anyone
considered converting the outrigger hinge into a wing fence to help stop
spanwise
Flow and thus induced drag in this area. Most of us use the speed kit
fairings to reduce drag, surely extending this fairing forward just short
of the leading edge and nicely blending it would improve the rather abrupt
protrusion of the fairing now and help to stop spanwise flow at the same
time.
Just a thought
Regards
Craig
Do Not Archive
Message 3
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| Subject: | Re: seals for control surfaces |
Craig=0AI don't think it would. First it would tend to disrupt the laminar
flow on the first 40% of the wing and that would increase it.=0ALaminar flo
w is just as important under the wing as on top imho.=0AGraham=0A=0A=0A=0A_
_______________________________=0A From: craig <craigb@onthenet.com.au>=0AT
o: europa-list@matronics.com =0ASent: Sunday, 5 August 2012, 10:13=0ASubjec
t: RE: Europa-List: seals for control surfaces=0A =0A=0A =0AWhile the subje
ct of seals has veered into the subject of Drag,=0Ahas anyone considered co
nverting the outrigger hinge into a wing fence to help=0Astop spanwise=0AFl
ow and thus induced drag in this area. Most of us use the=0Aspeed kit fairi
ngs to reduce drag, surely -extending this fairing forward=0Ajust short o
f the leading edge and nicely blending it would improve the rather=0Aabrupt
protrusion of the fairing now and help to stop spanwise flow at the same
=0Atime.=0A-=0AJust a thought=0A-=0ARegards=0ACraig=0A-=0ADo Not Arch
================
Message 4
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| Subject: | Re: seals for control surfaces |
Well spotted Fred! What John says makes sense to me=0AGraham=0A=0A=0A=0A___
_____________________________=0A From: Fred Klein <fklein@orcasonline.com>
=0ATo: europa-list@matronics.com =0ASent: Saturday, 4 August 2012, 18:03=0A
Subject: Europa-List: seals for control surfaces=0A =0A=0AApropos the recen
t thread on this topic, I found an old posting by John Lawton which may be
enlightening:=0A=0AIn a message dated 5/9/2007 2:59:30 AM Eastern Daylight
Time,-europa-list@matronics.com-writes:=0A>My understanding is that pre
venting the air going over the flap, in-=0A>>cruise, reduces drag, result
ing in higher cruise speed, which I have-=0A>>experienced.- I don't hav
e the engineering background to completely-=0A>>understand what is happen
ing to the wing, in flight.- That's why I-=0A>>depend on the guys on th
e list to keep me straight.- I'm more of a "try-=0A>>it and see" kinda
guy... :)- John's advice is based on the success that-=0A>>the glider g
uys have had, sealing the gaps.- It seems to have worked on-=0A>>Baby B
lue, as well.- Continued testing will tell to what degree of-=0A>>advan
tage the seals make.- It may very well prove that the extra few-=0A>>kn
ots is not worth the float upon landing.- I won't know until I satisfy-
=0A>>myself that I've explored all the angles (and strip widths)... ;)=0A>
-=0A>Hey Jeff, et al,=0A>-=0A>The concept behind seals is pretty simple
. In flight the wing creates a low pressure area on the top and high pressu
re on the bottom.-(Bernoulli at it again)-This pressure differential wi
ll try to equalize through the gap in the flap area and the hinge line of t
he ailerons. This is also true to some extent on the rudder hinge line and
the-trim tabs when they are deflected.-This equalization causes drag, a
lot of drag. So, the idea behind seals, both flap gap and positive seals o
n ailerons (and rudder and trim tabs), is to prevent this pressure equaliza
tion.=0A>-=0A>On N245E I used PVC weather-strip to create the flap gap se
al. The size will depend on how big your gap is between the leading edge of
the flap and the flap closeout when retracted. Choose a foam that is sligh
tly thicker than the widest spot in the gap you have. The XS flap closeout
looks as if it were designed to be sealed, given the flat area at the botto
m rear-of the closeout. If you apply the foam strip to the area where the
flap "noses" into the closeout when up it will seal this area for cruise f
light, but still allow air to flow over the flap when extended. Use a foam
that crushes easily when the flap comes in contact with it. You-don't wan
t to use a foam that is too stiff or too thick or-else your flaps won't f
ully-retract. PVC weather-strip is-soft and pliable and works quite wel
l. It is also fairly UV resistant and is very cheap. It's available at any
hardware store in various thicknesses. We've found that open cell foams ten
d to not last
very long due to UV-and they don't seal as well as closed cell-foams l
ike PVC.-I also used weather-strip on the ends of my flaps so that they s
eal against the side of the fuselage when they are in the up position. Acco
rding to Bruce Carmichael, renowned Aerodynamicist who wrote a book on drag
reduction in homebuilts, the wing root/fuselage junction is another area o
f high drag on most airplanes. Sealing it up helps, too.=0A>-=0A>Aileron
seals are a bit more tricky to employ. Some folks apply Mylar strips over t
he hinge lines and think they've sealed their ailerons. This-is not-tru
e. Mylar-is not-a seal, but rather is applied-to help the boundary fl
ow stay attached over the hinge line.-Mylar is also somewhat cosmetic in
that-it hides the hinge line. At high speeds the Mylar will lift up off t
he wing due to the pressure equalization, thus negating the effects of any
sealing the Mylar might be offering. In some cases the Mylar will "buzz" at
high speeds.=0A>-=0A>For sealing ailerons you need to install what are k
nown as positive seals. These seals go from the leading edge of the aileron
to the rear of the closeout. There are commercially available materials fo
r this, including various types of cloth and Teflon tapes. Some folks even
use-cloth-tape along the length of the aileron on the undersurface. Thi
s is fine on low speed gliders, but I think at the speeds we fly this metho
d-likely creates more drag.-Personally, I like parachute cloth for maki
ng positive seals. Whatever you use it needs to be zero porosity, i.e., all
owing no airflow through the material. Parachute cloth is thin, flexible, z
ero porosity and-fits the bill here perfectly. Here at the 'Possum Werks
we use Parachute cloth almost exclusively to fabricate positive seals. (it
also helps that we have a parachute manufacturer a few miles down the road
that gives us their scraps)=0A>-=0A>First remove the aileron. Then, cut a
strip of parachute cloth about 3" wide exactly the length of the aileron.
The width you use might take some trial and error to get it right.-You do
n't want it so wide the-the material-bunches up when the aileron is-d
eflected. 2.5' to 3"-width should work on most Europas. Then, yellow cont
act cement is applied to the leading edge of the aileron, the rear of the c
loseout and the mating surfaces of the cloth. We use a brand of glue-call
ed Plio-bond. It's handy in that it comes in a small bottle with a brush ap
plicator.-3M also makes-good contact-cement if you can find it. Avoid
the water based stuff. It is crap.=0A>-=0A>Scuff the area to be glued wi
th 180 to-enhance the adhesion. Apply the glue in a swath about 3/8" wide
to both the seal, the aileron and closeout.-Use masking tape to keep you
r glue line to the prescribed width and remove the tape once the glue is dr
y.- You can also use the masking tape to provide a guide when you scuff t
he area to be glued, but wipe it with acetone to remove dust before putting
the-glue on.-Allow the glue to dry, usually about 20 minutes, remove t
he masking tape,-then stick the seal to the leading edge of the aileron f
irst, preferably while on your work bench. If you-screw something up Xyle
ne will remove the glue easily without harming your paint.-The next part
takes an extra set of hands.=0A>-=0A>With one person holding the aileron
close to the wing, attach the other half of the cloth to the closeout formi
ng an "S" pattern. Avoid wrinkles.-See this drawing for details:-http:/
/wingsandwheels.com/page28.htm=0A>-=0A>Then, reattach the aileron as you
would normally do. Check the throw and make sure you are not binding! If yo
u apply the seal correctly you will not even know it is there. I have also
sealed my rudder in a similar fashion as well as the trim tabs. They create
similar drag when deflected.=0A>-=0A>I can't say specifically-what imp
rovements have occurred in N245E as a result of the seals since I've not ev
er flown it without them. I can tell you that I exceed Europas published nu
mbers with a fixed pitch prop. I can also tell you that on gliders we gener
ally see 2 to 4 points increase in glide and a noticeable-decrease in sin
k rate, even on the old-"woodies",-after the application of seals.-In
power planes this translates to faster cruise, better climb rates-and be
tter fuel economy.=0A>-=0A>Anyway, hope it helps!=0A>=0A>Regards,=0A>-
==================
Message 5
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| Subject: | Re: Europa-List Digest: 2 Msgs - 08/04/12 |
Chris, go all the way down to the end any list message and you will find a l
ink for list un/subscription.
Do not archive
On Aug 5, 2012, at 1:59 AM, C DREWETT <drewettcj@btinternet.com> wrote:
> please de-list me
> Chris Drewett
>
> From: Europa-List Digest Server <europa-list@matronics.com>
> To: Europa-List Digest List <europa-list-digest@matronics.com>
> Sent: Sunday, 5 August 2012, 8:01
> Subject: Europa-List Digest: 2 Msgs - 08/04/12
>
> *
>
> =========================
> Online Versions of Today's List Digest Archive
> =========================
>
> Today's complete Europa-List Digest can also be found in either of the
> two Web Links listed below. The .html file includes the Digest formatted
> in HTML for viewing with a web browser and features Hyperlinked Indexes
> and Message Navigation. The .txt file includes the plain ASCII version
> of the Europa-List Digest and can be viewed with a generic text editor
> such as Notepad or with a web browser.
>
> HTML Version:
>
> http://www.matronics.com/digest/digestview.php?Style=82701&View=ht
ml&Chapter 12-08-04&Archive=Europa
>
> Text Version:
>
> http://www.matronics.com/digest/digestview.php?Style=82701&View=tx
t&Chapter 12-08-04&Archive=Europa
>
>
> ======================
> EMail Version of Today's List Digest Archive
> ======================
>
>
> ----------------------------------------------------------
> Europa-List Digest Archive
> ---
> Total Messages Posted Sat 08/04/12: 2
> ----------------------------------------------------------
>
>
> Today's Message Index:
> ----------------------
>
> 1. 10:06 AM - seals for control surfaces (Fred Klein)
> 2. 10:52 AM - Re: seals for control surfaces (Robert Borger)
>
>
>
> ________________________________ Message 1 _____________________________
________
>
>
> Time: 10:06:37 AM PST US
> From: Fred Klein <fklein@orcasonline.com>
> Subject: Europa-List: seals for control surfaces
>
> Apropos the recent thread on this topic, I found an old posting by
> John Lawton which may be enlightening:
>
> > In a message dated 5/9/2007 2:59:30 AM Eastern Daylight Time, europa-lis
t@matronics.com
>
> > writes:
> > My understanding is that preventing the air going over the flap, in
> > cruise, reduces drag, resulting in higher cruise speed, which I have
> > experienced. I don't have the engineering background to completely
> > understand what is happening to the wing, in flight. That's why I
> > depend on the guys on the list to keep me straight. I'm more of a
> > "try
> > it and see" kinda guy... :) John's advice is based on the success
> > that
> > the glider guys have had, sealing the gaps. It seems to have worked
> > on
> > Baby Blue, as well. Continued testing will tell to what degree of
> > advantage the seals make. It may very well prove that the extra few
> > knots is not worth the float upon landing. I won't know until I
> > satisfy
> > myself that I've explored all the angles (and strip widths)... ;)
> >
> > Hey Jeff, et al,
> >
> > The concept behind seals is pretty simple. In flight the wing
> > creates a low pressure area on the top and high pressure on the
> > bottom. (Bernoulli at it again) This pressure differential will try
> > to equalize through the gap in the flap area and the hinge line of
> > the ailerons. This is also true to some extent on the rudder hinge
> > line and the trim tabs when they are deflected. This equalization
> > causes drag, a lot of drag. So, the idea behind seals, both flap gap
> > and positive seals on ailerons (and rudder and trim tabs), is to
> > prevent this pressure equalization.
> >
> > On N245E I used PVC weather-strip to create the flap gap seal. The
> > size will depend on how big your gap is between the leading edge of
> > the flap and the flap closeout when retracted. Choose a foam that is
> > slightly thicker than the widest spot in the gap you have. The XS
> > flap closeout looks as if it were designed to be sealed, given the
> > flat area at the bottom rear of the closeout. If you apply the foam
> > strip to the area where the flap "noses" into the closeout when up
> > it will seal this area for cruise flight, but still allow air to
> > flow over the flap when extended. Use a foam that crushes easily
> > when the flap comes in contact with it. You don't want to use a foam
> > that is too stiff or too thick or else your flaps won't fully
> > retract. PVC weather-strip is soft and pliable and works quite well.
> > It is also fairly UV resistant and is very cheap. It's available at
> > any hardware store in various thicknesses. We've found that open
> > cell foams tend to not last very long due to UV and they don't seal
> > as well as closed cell foams like PVC. I also used weather-strip on
> > the ends of my flaps so that they seal against the side of the
> > fuselage when they are in the up position. According to Bruce
> > Carmichael, renowned Aerodynamicist who wrote a book on drag
> > reduction in homebuilts, the wing root/fuselage junction is another
> > area of high drag on most airplanes. Sealing it up helps, too.
> >
> > Aileron seals are a bit more tricky to employ. Some folks apply
> > Mylar strips over the hinge lines and think they've sealed their
> > ailerons. This is not true. Mylar is not a seal, but rather is
> > applied to help the boundary flow stay attached over the hinge line.
> > Mylar is also somewhat cosmetic in that it hides the hinge line. At
> > high speeds the Mylar will lift up off the wing due to the pressure
> > equalization, thus negating the effects of any sealing the Mylar
> > might be offering. In some cases the Mylar will "buzz" at high speeds.
> >
> > For sealing ailerons you need to install what are known as positive
> > seals. These seals go from the leading edge of the aileron to the
> > rear of the closeout. There are commercially available materials for
> > this, including various types of cloth and Teflon tapes. Some folks
> > even use cloth tape along the length of the aileron on the
> > undersurface. This is fine on low speed gliders, but I think at the
> > speeds we fly this method likely creates more drag. Personally, I
> > like parachute cloth for making positive seals. Whatever you use it
> > needs to be zero porosity, i.e., allowing no airflow through the
> > material. Parachute cloth is thin, flexible, zero porosity and fits
> > the bill here perfectly. Here at the 'Possum Werks we use Parachute
> > cloth almost exclusively to fabricate positive seals. (it also helps
> > that we have a parachute manufacturer a few miles down the road that
> > gives us their scraps)
> >
> > First remove the aileron. Then, cut a strip of parachute cloth about
> > 3" wide exactly the length of the aileron. The width you use might
> > take some trial and error to get it right. You don't want it so wide
> > the the material bunches up when the aileron is deflected. 2.5' to
> > 3" width should work on most Europas. Then, yellow contact cement is
> > applied to the leading edge of the aileron, the rear of the closeout
> > and the mating surfaces of the cloth. We use a brand of glue called
> > Plio-bond. It's handy in that it comes in a small bottle with a
> > brush applicator. 3M also makes good contact cement if you can find
> > it. Avoid the water based stuff. It is crap.
> >
> > Scuff the area to be glued with 180 to enhance the adhesion. Apply
> > the glue in a swath about 3/8" wide to both the seal, the aileron
> > and closeout. Use masking tape to keep your glue line to the
> > prescribed width and remove the tape once the glue is dry. You can
> > also use the masking tape to provide a guide when you scuff the area
> > to be glued, but wipe it with acetone to remove dust before putting
> > the glue on. Allow the glue to dry, usually about 20 minutes, remove
> > the masking tape, then stick the seal to the leading edge of the
> > aileron first, preferably while on your work bench. If you screw
> > something up Xylene will remove the glue easily without harming your
> > paint. The next part takes an extra set of hands.
> >
> > With one person holding the aileron close to the wing, attach the
> > other half of the cloth to the closeout forming an "S" pattern.
> > Avoid wrinkles. See this drawing for details: http://wingsandwheels.com/
page28.htm
> >
> > Then, reattach the aileron as you would normally do. Check the throw
> > and make sure you are not binding! If you apply the seal correctly
> > you will not even know it is there. I have also sealed my rudder in
> > a similar fashion as well as the trim tabs. They create similar drag
> > when deflected.
> >
> > I can't say specifically what improvements have occurred in N245E as
> > a result of the seals since I've not ever flown it without them. I
> > can tell you that I exceed Europas published numbers with a fixed
> > pitch prop. I can also tell you that on gliders we generally see 2
> > to 4 points increase in glide and a noticeable decrease in sink
> > rate, even on the old "woodies", after the application of seals. In
> > power planes this translates to faster cruise, better climb rates
> > and better fuel economy.
> >
> > Anyway, hope it helps!
> >
> > Regards,
> >
> > John Lawton
>
> ________________________________ Message 2 _____________________________
________
>
>
> Time: 10:52:40 AM PST US
> Subject: Re: Europa-List: seals for control surfaces
> From: Robert Borger <rlborger@mac.com>
>
> Fred,
>
> Thanks for digging this up. Very informative. Now, if I could just get
> my 914 running right=85
>
> Blue skies & tailwinds,
> Bob Borger
> Europa XS Tri, Rotax 914, Airmaster C/S Prop.
> Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP
> 3705 Lynchburg Dr.
> Corinth, TX 76208-5331
> Cel: 817-992-1117
> rlborger@mac.com
>
> On Aug 4, 2012, at 12:03 PM, Fred Klein <fklein@orcasonline.com> wrote:
>
> Apropos the recent thread on this topic, I found an old posting by John
> Lawton which may be enlightening:
>
> > In a message dated 5/9/2007 2:59:30 AM Eastern Daylight Time,
> europa-list@matronics.com writes:
> > My understanding is that preventing the air going over the flap, in
> > cruise, reduces drag, resulting in higher cruise speed, which I have
>
> > experienced. I don't have the engineering background to completely
> > understand what is happening to the wing, in flight. That's why I
> > depend on the guys on the list to keep me straight. I'm more of a
> "try
> > it and see" kinda guy... :) John's advice is based on the success
> that
> > the glider guys have had, sealing the gaps. It seems to have worked
> on
> > Baby Blue, as well. Continued testing will tell to what degree of
> > advantage the seals make. It may very well prove that the extra few
>
> > knots is not worth the float upon landing. I won't know until I
> satisfy
> > myself that I've explored all the angles (and strip widths)... ;)
> >
> > Hey Jeff, et al,
> >
> > The concept behind seals is pretty simple. In flight the wing creates
> a low pressure area on the top and high pressure on the bottom.
> (Bernoulli at it again) This pressure differential will try to equalize
> through the gap in the flap area and the hinge line of the ailerons.
> This is also true to some extent on the rudder hinge line and the trim
> tabs when they are deflected. This equalization causes drag, a lot of
> drag. So, the idea behind seals, both flap gap and positive seals on
> ailerons (and rudder and trim tabs), is to prevent this pressure
> equalization.
> >
> > On N245E I used PVC weather-strip to create the flap gap seal. The
> size will depend on how big your gap is between the leading edge of the
> flap and the flap closeout when retracted. Choose a foam that is
> slightly thicker than the widest spot in the gap you have. The XS flap
> closeout looks as if it were designed to be sealed, given the flat area
> at the bottom rear of the closeout. If you apply the foam strip to the
> area where the flap "noses" into the closeout when up it will seal this
> area for cruise flight, but still allow air to flow over the flap when
> extended. Use a foam that crushes easily when the flap comes in contact
> with it. You don't want to use a foam that is too stiff or too thick or
> else your flaps won't fully retract. PVC weather-strip is soft and
> pliable and works quite well. It is also fairly UV resistant and is very
> cheap. It's available at any hardware store in various thicknesses.
> We've found that open cell foams tend to not last very long due to UV
> and they don't seal as well as closed cell foams like PVC. I also used
> weather-strip on the ends of my flaps so that they seal against the side
> of the fuselage when they are in the up position. According to Bruce
> Carmichael, renowned Aerodynamicist who wrote a book on drag reduction
> in homebuilts, the wing root/fuselage junction is another area of high
> drag on most airplanes. Sealing it up helps, too.
> >
> > Aileron seals are a bit more tricky to employ. Some folks apply Mylar
> strips over the hinge lines and think they've sealed their ailerons.
> This is not true. Mylar is not a seal, but rather is applied to help the
> boundary flow stay attached over the hinge line. Mylar is also somewhat
> cosmetic in that it hides the hinge line. At high speeds the Mylar will
> lift up off the wing due to the pressure equalization, thus negating the
> effects of any sealing the Mylar might be offering. In some cases the
> Mylar will "buzz" at high speeds.
> >
> > For sealing ailerons you need to install what are known as positive
> seals. These seals go from the leading edge of the aileron to the rear
> of the closeout. There are commercially available materials for this,
> including various types of cloth and Teflon tapes. Some folks even use
> cloth tape along the length of the aileron on the undersurface. This is
> fine on low speed gliders, but I think at the speeds we fly this method
> likely creates more drag. Personally, I like parachute cloth for making
> positive seals. Whatever you use it needs to be zero porosity, i.e.,
> allowing no airflow through the material. Parachute cloth is thin,
> flexible, zero porosity and fits the bill here perfectly. Here at the
> 'Possum Werks we use Parachute cloth almost exclusively to fabricate
> positive seals. (it also helps that we have a parachute manufacturer a
> few miles down the road that gives us their scraps)
> >
> > First remove the aileron. Then, cut a strip of parachute cloth about
> 3" wide exactly the length of the aileron. The width you use might take
> some trial and error to get it right. You don't want it so wide the the
> material bunches up when the aileron is deflected. 2.5' to 3" width
> should work on most Europas. Then, yellow contact cement is applied to
> the leading edge of the aileron, the rear of the closeout and the mating
> surfaces of the cloth. We use a brand of glue called Plio-bond. It's
> handy in that it comes in a small bottle with a brush applicator. 3M
> also makes good contact cement if you can find it. Avoid the water based
> stuff. It is crap.
> >
> > Scuff the area to be glued with 180 to enhance the adhesion. Apply the
> glue in a swath about 3/8" wide to both the seal, the aileron and
> closeout. Use masking tape to keep your glue line to the prescribed
> width and remove the tape once the glue is dry. You can also use the
> masking tape to provide a guide when you scuff the area to be glued, but
> wipe it with acetone to remove dust before putting the glue on. Allow
> the glue to dry, usually about 20 minutes, remove the masking tape, then
> stick the seal to the leading edge of the aileron first, preferably
> while on your work bench. If you screw something up Xylene will remove
> the glue easily without harming your paint. The next part takes an extra
> set of hands.
> >
> > With one person holding the aileron close to the wing, attach the
> other half of the cloth to the closeout forming an "S" pattern. Avoid
> wrinkles. See this drawing for details:
> http://wingsandwheels.com/page28.htm
> >
> > Then, reattach the aileron as you would normally do. Check the throw
> and make sure you are not binding! If you apply the seal correctly you
> will not even know it is there. I have also sealed my rudder in a
> similar fashion as well as the trim tabs. They create similar drag when
> deflected.
> >
> > I can't say specifically what improvements have occurred in N245E as a
> result of the seals since I've not ever flown it without them. I can
> tell you that I exceed Europas published numbers with a fixed pitch
> prop. I can also tell you that on gliders we generally see 2 to 4 points
> increase in glide and a noticeable decrease in sink rate, even on the
> old "woodies", after the application of seals. In power planes this
> translates to faster cruise, better climb rates and better fuel economy.
> >
> > Anyway, hope it helps!
> >
> > Regards,
> >
> > John Lawton
>
>
> --> p; -Matt Dralle, Libution" ======
>
>
>
>
>
>
>
>
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