---------------------------------------------------------- Europa-List Digest Archive --- Total Messages Posted Mon 08/06/12: 10 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:50 AM - Re: seals for control surfaces (Frans Veldman) 2. 07:19 AM - Re: seals for control surfaces (Fred Klein) 3. 09:00 AM - big singles (Fred Klein) 4. 01:06 PM - Re: seals for control surfaces (Frans Veldman) 5. 02:28 PM - Winching attachment points to Tri Gear for Trailering (Alan Carter) 6. 04:55 PM - Re: Winching attachment points to Tri Gear for Trailering (Frans Veldman) 7. 05:30 PM - Re: Winching attachment points to Tri Gear for Trailering (Karl Heindl) 8. 07:06 PM - Re: seals for control surfaces (klinefelter.kevin@gmail.com) 9. 07:12 PM - Re: seals for control surfaces (Fred Klein) 10. 11:49 PM - Re: seals for control surfaces (GRAHAM SINGLETON) ________________________________ Message 1 _____________________________________ Time: 02:50:09 AM PST US From: Frans Veldman Subject: Re: Europa-List: seals for control surfaces On 08/04/2012 07:03 PM, Fred Klein wrote: > Apropos the recent thread on this topic, I found an old posting by John > Lawton which may be enlightening: Thanks Fred! >> 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. I never understood why these seals are not standard on the Europa. I have seen them on other brands of homebuilts. Not only do they enhance the performance, but they are also esthetically more attractive than just a (often uneven) gap or a hinge line. >> 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. How much air is going to this gap with the flaps extended? Is it possible to make the underside of the wing flush with the flaps when the flaps are retracted? This would reduce the size of the gap with the flaps extended, does this have consequences? >> 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. Especially on the Europa, where both the wing and fuselage have a very low pressure area at the same datum, the only good solution is to fill in this area, like with Fred Klein's wing root fairings. Another important thing here is to seal the doors properly. Otherwise the suction will cause the doors to bulge out, releasing massive amounts of turbulent air. >> 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, What if you seal both surfaces of the ailerons? The seal where the highest pressure is (most likely the one at the underside of the wing) will be pushed snug against the surface, blocking any leakage. I have seals on the flaps and aileron and haven't observed any lifting of the seals during flight. >> 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. I find this a bit tricky. I can imagine that with such seals, inside the closeout, can deform, get loose, wrap up, bulge out, and somehow jam the ailerons. With standard Mylar seals applied on the outside you can't think of any serious failure. If they get loose, they will just fly away. >> In power planes >> this translates to faster cruise, better climb rates and better fuel >> economy. I think many of us have invested more time and money for less performance gain... Frans ________________________________ Message 2 _____________________________________ Time: 07:19:25 AM PST US From: Fred Klein Subject: Re: Europa-List: seals for control surfaces Frans...see indented comments below...Fred On Aug 6, 2012, at 3:42 AM, Frans Veldman wrote: > How much air is going to this gap with the flaps extended? Is it > possible to make the underside of the wing flush with the flaps when > the > flaps are retracted? ..."possible"...but not necessarily desireable...this type of gap seal was installed on Cessna 180s with decidedly mixed results...though it was a factory engineered mod which (presumably) thru testing showed benefits, many Cessna owners have faulted them as the source of nasty manners during landings & takeoffs...I found a current thread on the subject w/ the help of Mr. Google, and by chance had a lengthy conversation w/ a 180 owner this weekend who is very happy that he removed them. > This would reduce the size of the gap with the flaps extended, does > this have consequences? I would think so, and not necessarily positive. I'd classify the Europa flap as a "slotted flap" which is generally designed to allow substantial airflow thru the slot which I believe is intended to promote the attachment of the boundary layer to the upper surface of the flap...a good thing, no? I would think that if the compressible flap gap seal which John Lawton recommends was sliced from a circular rod of closed cell foam (known as "backer rod" and used in the US for sealing the joint between concrete and the sill plate of a wood wall) would have minimal disruption of airflow thru the slot. As you can read from my use of terms that I have only a fuzzy awareness of this stuff, so take my comments with a grain of salt. Fred ________________________________ Message 3 _____________________________________ Time: 09:00:15 AM PST US From: Fred Klein Subject: Europa-List: big singles After Raimo's upcoming adventures w/ his AN-2, these pixs may pale by comparison, but here on little Orcas Island in the Pacific NW (KORS) of the US are based two large singles from 1929...the last flying Hamilton Metal Plane, and a Travel Air S6000B which were on display at our annual fly-in this weekend...quite a treat! Fred do not archive DSCN6485.JPG DSCN6488.JPG ________________________________ Message 4 _____________________________________ Time: 01:06:20 PM PST US From: Frans Veldman Subject: Re: Europa-List: seals for control surfaces On 08/06/2012 04:18 PM, Fred Klein wrote: >> How much air is going to this gap with the flaps extended? Is it >> possible to make the underside of the wing flush with the flaps when the >> flaps are retracted? > > ..."possible"...but not necessarily desireable...this type of gap seal > was installed on Cessna 180s with decidedly mixed results... I know it was an option on Cessna's but I didn't know about the mixed results. >> This would reduce the size of the gap with the flaps extended, does >> this have consequences? > > I would think so, and not necessarily positive. I'd classify the Europa > flap as a "slotted flap" which is generally designed to allow > substantial airflow thru the slot which I believe is intended to promote > the attachment of the boundary layer to the upper surface of the > flap...a good thing, no? Yes. But the current slot is a 90 degree corner, and apperently you can also put cell foam in it as a seal. Id doesn't look like it allows lot of air through. That's why I wondered whether some "lip" at the bottom of this slot would make things different. > I would think that if the compressible flap gap seal which John Lawton > recommends was sliced from a circular rod of closed cell foam (known as > "backer rod" and used in the US for sealing the joint between concrete > and the sill plate of a wood wall) would have minimal disruption of > airflow thru the slot. Yes, but he mentions in the email that "the XS-wing looks like it has been designed with a seal in mind, because it has a flat area at the bottom of the slot." But at the bottom of the slot the gap is at its widest point, far too wide for a foam seal. So I'm a bit confused here as what he means. > As you can read from my use of terms that I have only a fuzzy awareness > of this stuff, so take my comments with a grain of salt. Same here. I hope to find someone who can shed some more light onto this matter. Frans ________________________________ Message 5 _____________________________________ Time: 02:28:45 PM PST US Subject: Europa-List: Winching attachment points to Tri Gear for Trailering From: "Alan Carter" Hello All I am thinking of using a trailer for my Tri Gear, I will need to winch the aircraft onto a trailer, nose first. The way i see it, you can attach a 3 web straps to the inner part of the Prop, not sure if this is a good idea.? Or straps to the tops of the undercarriage struts, but a small area of leg fairing will will need to be removed to accommodate the straps the strap going round the top of the leg and between the brake pipe , this seem to be a Strong place to connect to, maybe some type of bolt on towing eye affixed to the top of the legs then nylon straps to cable and winch may have been developed. Or straps to the bottom of the undercarriage legs the fairing at this point is not in the way, nor is the brake pipe. I don,t really want to drill and fix to the fuselage. Any ideas on this, Winching and trailering. Regards Alan Read this topic online here: http://forums.matronics.com/viewtopic.php?p=380219#380219 ________________________________ Message 6 _____________________________________ Time: 04:55:37 PM PST US From: Frans Veldman Subject: Re: Europa-List: Winching attachment points to Tri Gear for Trailering On 08/06/2012 11:27 PM, Alan Carter wrote: > I am thinking of using a trailer for my Tri Gear, > I will need to winch the aircraft onto a trailer, nose first. Why would you want to trailer it nose first? This has several disadvantages: 1) The weight of the airplane is on the nose. Consequently, the axle of the trailer needs do be near the front of the trailer, which makes manouvring on the road awkward. 2) When unloading the aircraft from the trailer, you need to hold the weight of the airplane, if you let go inadvertently you will get a tailstrike (the airplane will tip over on its tail easily, especially when the airplane is tilted backwards), and you also constantly need to keep the nosewheel from castering into reverse while it is moving "downhill in reverse" from the trailer. 3) You will need a nosewheel track all the way to the front of the trailer. This will make it nearly impossible to use a self-tilting trailer, and thus you will need some sort of a ramp. 4) If you have wheel fairings, they will probably hit the ground during unloading, due to the angle of the airplane. I have the airplane tail first on the trailer. The trailer tilts automatically by the shift of the weight of the airplane, no ramps needed. To tow the aircraft onto the trailer, I have made two attachement points near the main gear. (I figure the airplane has it strongest points near the main gear). By adjusting the lenght of each "leg" of the resulting "V"-cable, I have made the aircraft to follow the short track onto the trailer precisely while winching. Frans ________________________________ Message 7 _____________________________________ Time: 05:30:37 PM PST US From: Karl Heindl Subject: RE: Europa-List: Winching attachment points to Tri Gear for Trailering Hi Alan=2C I also installed two attachment points in the form of ss 8mm eyebolts immed iately behind where the legs enter the fuselage. You drill from inside the baggage area=2C through the embedded steel plate=2C and using large washers inside and out to distribute the load. It's a simple job. Karl > Subject: Europa-List: Winching attachment points to Tri Gear for Traileri ng > From: alancarteresq@onetel.net > Date: Mon=2C 6 Aug 2012 14:27:52 -0700 > To: europa-list@matronics.com > t> > > Hello All > I am thinking of using a trailer for my Tri Gear=2C > I will need to winch the aircraft onto a trailer=2C nose first. > The way i see it=2C you can attach a 3 web straps to the inner part of th e Prop=2C not sure if this is a good idea.? > Or straps to the tops of the undercarriage struts=2C but a small area of leg fairing will will need to be removed to accommodate the straps the str ap going round the top of the leg and between the brake pipe =2C this seem to be a Strong place to connect to=2C maybe some type of bolt on towing ey e affixed to the top of the legs then nylon straps to cable and winch may h ave been developed. > Or straps to the bottom of the undercarriage legs the fairing at this poi nt is not in the way=2C nor is the brake pipe. > I don=2Ct really want to drill and fix to the fuselage. > Any ideas on this=2C Winching and trailering. > Regards > Alan > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=380219#380219 > > > > > > > =========== =========== =========== =========== > > > ________________________________ Message 8 _____________________________________ Time: 07:06:03 PM PST US From: klinefelter.kevin@gmail.com Subject: Re: Europa-List: seals for control surfaces Frans, I think he means put the foam PVC weatherstrip about where the gap between the forward most part of the retracted flap and the closeout is. So when the flap is retracted, the "leading edge" of the flap just touches and even compresses the foam. This should help keep the higher pressure air under the wing from going up top. So there is no "lip" at the bottom of the slot, the foam strip is attached up the closeout a bit where the space between the leading edge of the flap and the closeout is smallest. I have been flying my Mono this way for quite a while now and have not noticed any negative effects. So the objective here is to keep the higher pressure air down where it belongs, not to "smooth out" the gap between the lower wing and flap bottom surface. I think if you attached a Mylar strip to the bottom of the wing to span the gap to the flap, it would screw up the air flow thru the "slot" when the flap is down, making our slotted flaps less effective... I think. Kevin On Aug 6, 2012, at 1:58 PM, Frans Veldman wrote: > > On 08/06/2012 04:18 PM, Fred Klein wrote: > >>> How much air is going to this gap with the flaps extended? Is it >>> possible to make the underside of the wing flush with the flaps when the >>> flaps are retracted? >> >> ..."possible"...but not necessarily desireable...this type of gap seal >> was installed on Cessna 180s with decidedly mixed results... > > I know it was an option on Cessna's but I didn't know about the mixed > results. > >>> This would reduce the size of the gap with the flaps extended, does >>> this have consequences? >> >> I would think so, and not necessarily positive. I'd classify the Europa >> flap as a "slotted flap" which is generally designed to allow >> substantial airflow thru the slot which I believe is intended to promote >> the attachment of the boundary layer to the upper surface of the >> flap...a good thing, no? > > Yes. But the current slot is a 90 degree corner, and apperently you can > also put cell foam in it as a seal. Id doesn't look like it allows lot > of air through. That's why I wondered whether some "lip" at the bottom > of this slot would make things different. > >> I would think that if the compressible flap gap seal which John Lawton >> recommends was sliced from a circular rod of closed cell foam (known as >> "backer rod" and used in the US for sealing the joint between concrete >> and the sill plate of a wood wall) would have minimal disruption of >> airflow thru the slot. > > Yes, but he mentions in the email that "the XS-wing looks like it has > been designed with a seal in mind, because it has a flat area at the > bottom of the slot." But at the bottom of the slot the gap is at its > widest point, far too wide for a foam seal. So I'm a bit confused here > as what he means. > >> As you can read from my use of terms that I have only a fuzzy awareness >> of this stuff, so take my comments with a grain of salt. > > Same here. I hope to find someone who can shed some more light onto this > matter. > > Frans > > > > > ________________________________ Message 9 _____________________________________ Time: 07:12:24 PM PST US From: Fred Klein Subject: Re: Europa-List: seals for control surfaces Frans...indented comments below...Fred On Aug 6, 2012, at 1:58 PM, Frans Veldman wrote: > > > > On 08/06/2012 04:18 PM, Fred Klein wrote: > >>> How much air is going to this gap with the flaps extended? Is it >>> possible to make the underside of the wing flush with the flaps >>> when the >>> flaps are retracted? >> >> ..."possible"...but not necessarily desireable...this type of gap >> seal >> was installed on Cessna 180s with decidedly mixed results... > > I know it was an option on Cessna's but I didn't know about the mixed > results. > >>> This would reduce the size of the gap with the flaps extended, does >>> this have consequences? >> >> I would think so, and not necessarily positive. I'd classify the >> Europa >> flap as a "slotted flap" which is generally designed to allow >> substantial airflow thru the slot which I believe is intended to >> promote >> the attachment of the boundary layer to the upper surface of the >> flap...a good thing, no? > > Yes. But the current slot is a 90 degree corner, true enough...but I measure the radius of the corner of the closeout at about 3/8" and the radius of the forward portion of the lower surface of the flap at approximately 3/4" which invite the air to flow up thru the slot... > and apperently you can also put cell foam in it as a seal. Id > doesn't look like it allows lot of air through. well...I guess "a lot" depends upon one's point of view...recognise that the air is flowing from high pressure / low velocity to low pressure / high velocity so I'd say that a lot of air is being sucked up into the gap and blown out the rear across the top surface of the flap. > That's why I wondered whether some "lip" at the bottom > of this slot would make things different. On my plane, such a "lip"...if it is intended to provide a smooth, continuous bridge over the gap between flap and wing when flap is retracted...would have to be between 1.5" and 2" wide, and stiff enough so that it would not just get sucked up into the gap the first time the flaps are deployed...and if it were sufficiently stiff, it would seem to me that at that width it would seriously degrade the air flow thru the slot w/ flap deployed. > >> I would think that if the compressible flap gap seal which John >> Lawton >> recommends was sliced from a circular rod of closed cell foam >> (known as >> "backer rod" and used in the US for sealing the joint between >> concrete >> and the sill plate of a wood wall) would have minimal disruption of >> airflow thru the slot. > > Yes, but he mentions in the email that "the XS-wing looks like it has > been designed with a seal in mind, because it has a flat area at the > bottom of the slot." Lawton wrote: 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. Notice that John does not advocate placing the compressible foam seal at the lowermost portion of the flat area but rather "where the flap 'noses' into the closeout" when flap is in the retracted position; on my plane, this location is about 1" up from the lower.surface of the wing. This location, at least on my plane, is the place where the "slot" is narrowest when the flap is retracted, and widest when the flap is deployed. Thus the location is optimal for using the thinnest seal w/ minimal interference of air flow when flap is deployed. I plan to use3/8" diameter backer rod sliced in half. > But at the bottom of the slot the gap is at its widest point, far > too wide for a foam seal. So I'm a bit confused here > as what he means. When John wrote "bottom of the slot", I did not infer that he intended the literally lowest point of the slot but rather the portion of the closeout which is flat and vertical. Indeed, gap at the literal "bottom of the slot" which would include the radii of the closeout and the forwardmost portion of the lower surface of the flat on my plane would require that 1.5" to 2" wide "lip". >> As you can read from my use of terms that I have only a fuzzy >> awareness >> of this stuff, so take my comments with a grain of salt. > > Same here. I hope to find someone who can shed some more light onto > this > matter. Piry we don't have a resident aerodynamicist to keep us luftmensch in chek, Fred ________________________________ Message 10 ____________________________________ Time: 11:49:43 PM PST US From: GRAHAM SINGLETON Subject: Re: Europa-List: seals for control surfaces Fred, hopefully Ivan might have an opinion on this, I know he's been away b ut should-be-back now. Ivan?=0AIf you look at the definitive digital co ordinates of the-section-you will see first of all-that-the bottom surface is not flat but slightly convex,=0Aso there is a slight reflex at the trailing edge. This will have an effect on drag in the cruise. I think it's important to have smooth airflow through the gap=0Awhen the flap is de ployed to keep airflow attached over the flap. I don't think we need to sea l the LE of the flap flap up because we aren't looking for optimum lift=0Aw e want minimum drag in any case the pressure top and bottom will be almost equal at this point. The control surfaces are different, here we want more effect without increasing drag.=0AGraham=0A=0A=0A__________________________ ______=0A From: Fred Klein =0ATo: europa-list@matro nics.com =0ASent: Tuesday, 7 August 2012, 3:11=0ASubject: Re: Europa-List: seals for control surfaces=0A =0A=0AFrans...indented comments below...Fred =0A=0A=0AOn Aug 6, 2012, at 1:58 PM, Frans Veldman wrote:=0A=0A--> Europa-L ist message posted by: Frans Veldman =0A>=0A>On 08/ 06/2012 04:18 PM, Fred Klein wrote:=0A>=0A>=0A>How much air is going to thi s gap with the flaps extended? Is it=0A>>>=0A>possible to make the undersid e of the wing flush with the flaps when the=0A>>>=0A>flaps are retracted? =0A>>>=0A>=0A>>=0A>..."possible"...but not necessarily desireable...this ty pe of gap seal=0A>>=0A>was installed on Cessna 180s with decidedly mixed re sults...=0A>>=0A>I know it was an option on Cessna's but I didn't know abou t the mixed=0A>results.=0A>=0A>=0A>This would reduce the size of the gap wi th the flaps extended, does=0A>>>=0A>this have consequences?=0A>>>=0A>=0A>> =0A>I would think so, and not necessarily positive. I'd classify the Europa =0A>>=0A>flap as a "slotted flap" which is generally designed to allow=0A>> =0A>substantial airflow thru the slot which I believe is intended to promot e=0A>>=0A>the attachment of the boundary layer to the upper surface of the =0A>>=0A>flap...a good thing, no?=0A>>=0A>Yes. But the current slot is a 90 degree corner, =0A=0Atrue enough...but I measure the radius of the corner of the closeout at about 3/8" and the radius of the forward portion of the lower surface of the flap at approximately 3/4" which invite the air to flo w up thru the slot...=0A=0Aand apperently you can-also put cell foam in i t as a seal. Id doesn't look like it allows lot-of air through.=0Awell... I guess "a lot" depends upon one's point of view...recognise that the air i s flowing from high pressure / low velocity to low pressure / high velocity so I'd say that a lot of air is being sucked up into the gap and blown out the rear across the top surface of the flap.-=0A=0A=0AThat's why I wonde red whether some "lip" at the bottom=0A>of this slot would make things diff erent.=0A>=0AOn my plane, such a "lip"...if it is intended to provide a smo oth, continuous bridge over the gap between flap and wing when flap is retr acted...would have to be between 1.5" and 2" wide, and stiff enough so that it would not just get sucked up into the gap the first time the flaps are deployed...and if it were sufficiently stiff, it would seem to me that at t hat width it would seriously degrade the air flow thru the slot w/ flap dep loyed.=0A=0A=0A>=0A>I would think that if the compressible flap gap seal wh ich John Lawton=0A>>=0A>recommends was sliced from a circular rod of closed cell foam (known as=0A>>=0A>"backer rod" and used in the US for sealing th e joint between concrete=0A>>=0A>and the sill plate of a wood wall) would h ave minimal disruption of=0A>>=0A>airflow thru the slot.=0A>>=0A>Yes, but h e mentions in the email that "the XS-wing looks like it has=0A>been designe d with a seal in mind, because it has a flat area at the=0A>bottom of the s lot." =0A=0ALawton wrote:=0A=0AThe XS flap closeout looks as if it were des igned to be sealed, given the flat area at the bottom rear-of the closeou t. 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.=0A=0ANotice that John does not adv ocate placing the compressible foam seal at the lowermost portion of the fl at area but rather "where the flap 'noses' into the closeout" when flap is in the retracted position; on my plane, this location is about 1" up from t he lower.surface of the wing. This location, at least on my plane, is the p lace where the "slot" is narrowest when the flap is retracted, and widest w hen the flap is deployed. Thus the location is optimal for using the thinne st seal w/ minimal interference of air flow when flap is deployed. I plan t o use3/8" diameter backer rod sliced in half.=0A=0ABut at the bottom of the slot the gap is at its-widest point, far too wide for a foam seal. So I' m a bit confused here=0A>as what he means.=0A>=0AWhen John wrote "bottom of the slot", I did not infer that he intended the literally lowest point of the slot but rather the portion of the closeout which is flat and vertical. =0A=0AIndeed, gap at the literal "bottom of the slot" which would include t he radii of the closeout and the forwardmost portion of the lower surface o f the flat on my plane would require that 1.5" to 2" wide "lip".=0A=0A=0AAs you can read from my use of terms that I have only a fuzzy awareness=0A>> =0A>of this stuff, so take my comments with a grain of salt.=0A>>=0A>Same h ere. I hope to find someone who can shed some more light onto this=0A>matte r.=0A>=0APiry we don't have a resident aerodynamicist to keep us luftmensch =================== ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message europa-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Europa-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/europa-list Browse Digests http://www.matronics.com/digest/europa-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.