KR> Bellyboard
Hi George, It?s not a ?Brit thing?. In geometry ?normal? is the expression used to describe a line which perpendicular to a surface. In the case described in the research paper, the flat plate was rigged in the wind tunnel so that it was normal to airflow. On a KR fuselage, the bellyboard would only be normal to the flow if it was deployed at 90 degrees. Developing nations have no cause to feel inferior! Have a good 2015. Mike _ From: gluejam [mailto:gluejam at cox.net] Sent: 01 January 2015 19:05 To: Mike; KRnet Subject: Re: KR> Bellyboard Mike - Perhaps you can explain why in the report the term, "normal to the airflow" rather 'than parallel with', or 'perpendicular to' the airflow is used. Is that a common reference in the UK? It just seems a little nebulous to me in understanding immediately upon reading the report, and it would seem sensible to think that normal would be in line with airflow . . . but then ours (US) is a lower grade society, after all !! George _ On 12/31/2014 6:19 AM, Mike via KRnet wrote: A little science from English researchers in 1957 http://naca.central.cranfield.ac.uk/reports/arc/cp/0323.pdf but I'm sure there must be more recent published findings from elsewhere. This suggests that a solid airbrake produces a bubble of reduced airflow behind the brake with airflow velocity fluctuations occurring around the edge of the brake which may cause vibrations to the structure. Perforations in the airbrake reduce this effect and were found to be more effective towards the centre of the plate than around the periphery. >From the Pprune forum, this explanation was offered: "Perforation reduces buffeting downrange of the speed brake, and reduces its interference with flying surfaces or the fuselage or wing or horizontal stab. Remember, the speed brake is there to create drag, but not undesirable flight characteristics. A perforated brake doesn't create nearly the airflow disruption, pitch change, or load on the surrounding and supporting structure that a solid brake might create. The number and placement of holes are important considerations, and part of the design. Holes permit a lighter structure that takes less of an airload, reducing not only the weight of the brake assembly but the force required to actuate it and the structure around it that must support the load. Remember that much of the time, that speed brake isn't anything but dead weight." Mike Mold Devon, UK. -Original Message- From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Mac McConnell-Wood via KRnet Sent: 31 December 2014 10:35 To: Herbert F?rle; KRnet Subject: Re: KR> Bellyboard The RAF Vulcan bomber had solid airbrakes-no holes (which enabled this 90 ton delta to descend vertically-..been there..) Mac On Wed, Dec 31, 2014 at 9:51 AM, Herbert F?rle <mailto:krnet at list.krnet.org> wrote: any Test,however it is performed,gives a lot of informations! The aerodynamic principles are always the same ,also in the case of the hot" bellyboard -drag" discusion.For me it's important the location of the board and I think the place underneath the rearspar is very well chosen ( far enough behind the CG ,to give the Kr a small amount of direction stability like a dragchute and the waketurbulences does'nt hit the HS !) I 'm convinced,a board without holes are more effectiv ( one big waketurbulence produce more drag compared to many small ones). I'm also think,a big advantage of the bellyboard is the fact ,that you can lower the nose of the Kr on final for better sight( wether you have to push or pull the stik )! Herbert German Kr builder . Von meinem iPad gesendet ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options _ <http://www.avast.com/> This email has been checked for viruses by Avast antivirus software. www.avast.com <http://www.avast.com/>
KR> Bellyboard
Mike, I love that math/ geometry, and science, keep it coming. Larry Bell On Fri, Jan 2, 2015 at 12:58 AM, Mike via KRnet wrote: > Hi George, > > It?s not a ?Brit thing?. In geometry ?normal? is the expression used to > describe a line which perpendicular to a surface. In the case described in > the research paper, the flat plate was rigged in the wind tunnel so that it > was normal to airflow. On a KR fuselage, the bellyboard would only be > normal > to the flow if it was deployed at 90 degrees. > > > > Developing nations have no cause to feel inferior! > > > > Have a good 2015. > > Mike > > > > _ > > From: gluejam [mailto:gluejam at cox.net] > Sent: 01 January 2015 19:05 > To: Mike; KRnet > Subject: Re: KR> Bellyboard > > > > Mike - > > Perhaps you can explain why in the report the term, "normal to the airflow" > rather 'than parallel with', or 'perpendicular to' the airflow is used. > Is > that a common reference in the UK? It just seems a little nebulous to me > in understanding immediately upon reading the report, and it would seem > sensible to think that normal would be in line with airflow . . . > but then ours (US) is a lower grade society, after all !! > > George > > _ > > > > On 12/31/2014 6:19 AM, Mike via KRnet wrote: > > A little science from English researchers in 1957 > http://naca.central.cranfield.ac.uk/reports/arc/cp/0323.pdf but I'm sure > there must be more recent published findings from elsewhere. > > This suggests that a solid airbrake produces a bubble of reduced airflow > behind the brake with airflow velocity fluctuations occurring around the > edge of the brake which may cause vibrations to the structure. Perforations > in the airbrake reduce this effect and were found to be more effective > towards the centre of the plate than around the periphery. > > From the Pprune forum, this explanation was offered: "Perforation reduces > buffeting downrange of the speed brake, and reduces its interference with > flying surfaces or the fuselage or wing or horizontal stab. Remember, the > speed brake is there to create drag, but not undesirable flight > characteristics. A perforated brake doesn't create nearly the airflow > disruption, pitch change, or load on the surrounding and supporting > structure that a solid brake might create. The number and placement of > holes > are important considerations, and part of the design. Holes permit a > lighter > structure that takes less of an airload, reducing not only the weight of > the > brake assembly but the force required to actuate it and the structure > around > it that must support the load. Remember that much of the time, that speed > brake isn't anything but dead weight." > > Mike Mold > Devon, UK. > > -Original Message- > From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Mac > McConnell-Wood via KRnet > Sent: 31 December 2014 10:35 > To: Herbert F?rle; KRnet > Subject: Re: KR> Bellyboard > > The RAF Vulcan bomber had solid airbrakes-no holes (which enabled this 90 > ton delta to descend vertically-..been there..) > Mac > > On Wed, Dec 31, 2014 at 9:51 AM, Herbert F?rle > <mailto:krnet at list.krnet.org> wrote: > > > > any Test,however it is performed,gives a lot of informations! The > aerodynamic principles are always the same ,also in the case of the hot" > bellyboard -drag" discusion.For me it's important the location of the > > board > > and I think the place underneath the rearspar is very well chosen ( far > enough behind the CG ,to give the Kr a small amount of direction stability > like a dragchute and the waketurbulences does'nt hit the HS !) I 'm > convinced,a board without holes are more effectiv ( one big > > waketurbulence > > produce more drag compared to many small ones). > I'm also think,a big advantage of the bellyboard is the fact ,that you can > lower the nose of the Kr on final for better sight( wether you have to > > push > > or pull the stik )! > Herbert > German Kr builder . > > > Von meinem iPad gesendet > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options > > > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at
KR> Bellyboard
Normal means perpendicular. Its just a mathematical term. On Jan 1, 2015 7:05 PM, "gluejam via KRnet" wrote: > > Mike - > > Perhaps you can explain why in the report the term, "/normal to the airflow/" rather 'than parallel with', or 'perpendicular to' the airflow is used. Is that a common reference in the UK? It just seems a little nebulous to me in understanding immediately upon reading the report, and it would seem sensible to think that normal would be in line with airflow . . . > but then ours (US) is a lower grade society, after all !! > > George > > > > > On 12/31/2014 6:19 AM, Mike via KRnet wrote: >> >> A little science from English researchers in 1957 >> http://naca.central.cranfield.ac.uk/reports/arc/cp/0323.pdf but I'm sure >> there must be more recent published findings from elsewhere. >> >> This suggests that a solid airbrake produces a bubble of reduced airflow >> behind the brake with airflow velocity fluctuations occurring around the >> edge of the brake which may cause vibrations to the structure. Perforations >> in the airbrake reduce this effect and were found to be more effective >> towards the centre of the plate than around the periphery. >> >> From the Pprune forum, this explanation was offered: "Perforation reduces >> buffeting downrange of the speed brake, and reduces its interference with >> flying surfaces or the fuselage or wing or horizontal stab. Remember, the >> speed brake is there to create drag, but not undesirable flight >> characteristics. A perforated brake doesn't create nearly the airflow >> disruption, pitch change, or load on the surrounding and supporting >> structure that a solid brake might create. The number and placement of holes >> are important considerations, and part of the design. Holes permit a lighter >> structure that takes less of an airload, reducing not only the weight of the >> brake assembly but the force required to actuate it and the structure around >> it that must support the load. Remember that much of the time, that speed >> brake isn't anything but dead weight." >> >> Mike Mold >> Devon, UK. >> >> -Original Message- >> From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Mac >> McConnell-Wood via KRnet >> Sent: 31 December 2014 10:35 >> To: Herbert F?rle; KRnet >> Subject: Re: KR> Bellyboard >> >> The RAF Vulcan bomber had solid airbrakes-no holes (which enabled this 90 >> ton delta to descend vertically-..been there..) >> Mac >> >> On Wed, Dec 31, 2014 at 9:51 AM, Herbert F?rle wrote: >> >>> any Test,however it is performed,gives a lot of informations! The >>> aerodynamic principles are always the same ,also in the case of the hot" >>> bellyboard -drag" discusion.For me it's important the location of the >> >> board >>> >>> and I think the place underneath the rearspar is very well chosen ( far >>> enough behind the CG ,to give the Kr a small amount of direction stability >>> like a dragchute and the waketurbulences does'nt hit the HS !) I 'm >>> convinced,a board without holes are more effectiv ( one big >> >> waketurbulence >>> >>> produce more drag compared to many small ones). >>> I'm also think,a big advantage of the bellyboard is the fact ,that you can >>> lower the nose of the Kr on final for better sight( wether you have to >> >> push >>> >>> or pull the stik )! >>> Herbert >>> German Kr builder . >>> >>> >>> Von meinem iPad gesendet >>> ___ >>> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. >>> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org >>> please see other KRnet info at http://www.krnet.org/info.html >>> see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change >>> options >>> >> ___ >> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. >> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org >> please see other KRnet info at http://www.krnet.org/info.html >> see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change >> options >> >> >> ___ >> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. >> To UNsubs
KR> Bellyboard
On Jan 1, 2015 1:36 PM, "Mac McConnell-Wood via KRnet" wrote: > > Avro's should have read that before designing the Vulcan air > brakesfancy putting those solid slabs upwind of the flying controls..! > > See the pairs of yellow lines indicating position. > That main control surfaces on a Delta wing is way out of the turbulence of the air brake... The vert is humongous! > Regards and a HNY to all our readers > Mac > > On Wed, Dec 31, 2014 at 1:19 PM, Mike via KRnet > wrote: > > > A little science from English researchers in 1957 > > http://naca.central.cranfield.ac.uk/reports/arc/cp/0323.pdf but I'm sure > > there must be more recent published findings from elsewhere. > > > > This suggests that a solid airbrake produces a bubble of reduced airflow > > behind the brake with airflow velocity fluctuations occurring around the > > edge of the brake which may cause vibrations to the structure. Perforations > > in the airbrake reduce this effect and were found to be more effective > > towards the centre of the plate than around the periphery. > > > > From the Pprune forum, this explanation was offered: "Perforation reduces > > buffeting downrange of the speed brake, and reduces its interference with > > flying surfaces or the fuselage or wing or horizontal stab. Remember, the > > speed brake is there to create drag, but not undesirable flight > > characteristics. A perforated brake doesn't create nearly the airflow > > disruption, pitch change, or load on the surrounding and supporting > > structure that a solid brake might create. The number and placement of > > holes > > are important considerations, and part of the design. Holes permit a > > lighter > > structure that takes less of an airload, reducing not only the weight of > > the > > brake assembly but the force required to actuate it and the structure > > around > > it that must support the load. Remember that much of the time, that speed > > brake isn't anything but dead weight." > > > > Mike Mold > > Devon, UK. > > > > -Original Message- > > From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Mac > > McConnell-Wood via KRnet > > Sent: 31 December 2014 10:35 > > To: Herbert F?rle; KRnet > > Subject: Re: KR> Bellyboard > > > > The RAF Vulcan bomber had solid airbrakes-no holes (which enabled this 90 > > ton delta to descend vertically-..been there..) > > Mac > > > > On Wed, Dec 31, 2014 at 9:51 AM, Herbert F?rle > > wrote: > > > > > > > > any Test,however it is performed,gives a lot of informations! The > > > aerodynamic principles are always the same ,also in the case of the hot" > > > bellyboard -drag" discusion.For me it's important the location of the > > board > > > and I think the place underneath the rearspar is very well chosen ( far > > > enough behind the CG ,to give the Kr a small amount of direction > > stability > > > like a dragchute and the waketurbulences does'nt hit the HS !) I 'm > > > convinced,a board without holes are more effectiv ( one big > > waketurbulence > > > produce more drag compared to many small ones). > > > I'm also think,a big advantage of the bellyboard is the fact ,that you > > can > > > lower the nose of the Kr on final for better sight( wether you have to > > push > > > or pull the stik )! > > > Herbert > > > German Kr builder . > > > > > > > > > Von meinem iPad gesendet > > > ___ > > > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > > > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > > > please see other KRnet info at http://www.krnet.org/info.html > > > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to > > change > > > options > > > > > ___ > > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > > please see other KRnet info at http://www.krnet.org/info.html > > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > > options > > > > > > ___ > > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > > please see other KRnet info at http://www.krnet.org/info.html > > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > > options > > > > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options >
KR> Bellyboard
Vulcan's are made of chunky aluminium. Its designed to handle all the stress. And at the speeds they fly the aerodynamics is different. Solid belly boards for krs would work fine. Those with holes are way more efficient though. You are the chief aerodynamicist! Take your pick! On Jan 1, 2015 1:36 PM, "Mac McConnell-Wood via KRnet" wrote: > > Avro's should have read that before designing the Vulcan air > brakesfancy putting those solid slabs upwind of the flying controls..! > > See the pairs of yellow lines indicating position. > > Regards and a HNY to all our readers > Mac > > On Wed, Dec 31, 2014 at 1:19 PM, Mike via KRnet > wrote: > > > A little science from English researchers in 1957 > > http://naca.central.cranfield.ac.uk/reports/arc/cp/0323.pdf but I'm sure > > there must be more recent published findings from elsewhere. > > > > This suggests that a solid airbrake produces a bubble of reduced airflow > > behind the brake with airflow velocity fluctuations occurring around the > > edge of the brake which may cause vibrations to the structure. Perforations > > in the airbrake reduce this effect and were found to be more effective > > towards the centre of the plate than around the periphery. > > > > From the Pprune forum, this explanation was offered: "Perforation reduces > > buffeting downrange of the speed brake, and reduces its interference with > > flying surfaces or the fuselage or wing or horizontal stab. Remember, the > > speed brake is there to create drag, but not undesirable flight > > characteristics. A perforated brake doesn't create nearly the airflow > > disruption, pitch change, or load on the surrounding and supporting > > structure that a solid brake might create. The number and placement of > > holes > > are important considerations, and part of the design. Holes permit a > > lighter > > structure that takes less of an airload, reducing not only the weight of > > the > > brake assembly but the force required to actuate it and the structure > > around > > it that must support the load. Remember that much of the time, that speed > > brake isn't anything but dead weight." > > > > Mike Mold > > Devon, UK. > > > > -Original Message- > > From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Mac > > McConnell-Wood via KRnet > > Sent: 31 December 2014 10:35 > > To: Herbert F?rle; KRnet > > Subject: Re: KR> Bellyboard > > > > The RAF Vulcan bomber had solid airbrakes-no holes (which enabled this 90 > > ton delta to descend vertically-..been there..) > > Mac > > > > On Wed, Dec 31, 2014 at 9:51 AM, Herbert F?rle > > wrote: > > > > > > > > any Test,however it is performed,gives a lot of informations! The > > > aerodynamic principles are always the same ,also in the case of the hot" > > > bellyboard -drag" discusion.For me it's important the location of the > > board > > > and I think the place underneath the rearspar is very well chosen ( far > > > enough behind the CG ,to give the Kr a small amount of direction > > stability > > > like a dragchute and the waketurbulences does'nt hit the HS !) I 'm > > > convinced,a board without holes are more effectiv ( one big > > waketurbulence > > > produce more drag compared to many small ones). > > > I'm also think,a big advantage of the bellyboard is the fact ,that you > > can > > > lower the nose of the Kr on final for better sight( wether you have to > > push > > > or pull the stik )! > > > Herbert > > > German Kr builder . > > > > > > > > > Von meinem iPad gesendet > > > ___ > > > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > > > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > > > please see other KRnet info at http://www.krnet.org/info.html > > > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to > > change > > > options > > > > > ___ > > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > > please see other KRnet info at http://www.krnet.org/info.html > > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > > options > > > > > > ___ > > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > > please see other KRnet info at http://www.krnet.org/info.html > > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > > options > > > > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options >
KR> Bellyboard
Mike - Perhaps you can explain why in the report the term, "/normal to the airflow/" rather 'than parallel with', or 'perpendicular to' the airflow is used. Is that a common reference in the UK? It just seems a little nebulous to me in understanding immediately upon reading the report, and it would seem sensible to think that normal would be in line with airflow . . . but then ours (US) is a lower grade society, after all !! George On 12/31/2014 6:19 AM, Mike via KRnet wrote: > A little science from English researchers in 1957 > http://naca.central.cranfield.ac.uk/reports/arc/cp/0323.pdf but I'm sure > there must be more recent published findings from elsewhere. > > This suggests that a solid airbrake produces a bubble of reduced airflow > behind the brake with airflow velocity fluctuations occurring around the > edge of the brake which may cause vibrations to the structure. Perforations > in the airbrake reduce this effect and were found to be more effective > towards the centre of the plate than around the periphery. > > From the Pprune forum, this explanation was offered: "Perforation reduces > buffeting downrange of the speed brake, and reduces its interference with > flying surfaces or the fuselage or wing or horizontal stab. Remember, the > speed brake is there to create drag, but not undesirable flight > characteristics. A perforated brake doesn't create nearly the airflow > disruption, pitch change, or load on the surrounding and supporting > structure that a solid brake might create. The number and placement of holes > are important considerations, and part of the design. Holes permit a lighter > structure that takes less of an airload, reducing not only the weight of the > brake assembly but the force required to actuate it and the structure around > it that must support the load. Remember that much of the time, that speed > brake isn't anything but dead weight." > > Mike Mold > Devon, UK. > > -Original Message- > From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Mac > McConnell-Wood via KRnet > Sent: 31 December 2014 10:35 > To: Herbert F?rle; KRnet > Subject: Re: KR> Bellyboard > > The RAF Vulcan bomber had solid airbrakes-no holes (which enabled this 90 > ton delta to descend vertically-..been there..) > Mac > > On Wed, Dec 31, 2014 at 9:51 AM, Herbert F?rle > wrote: > >> any Test,however it is performed,gives a lot of informations! The >> aerodynamic principles are always the same ,also in the case of the hot" >> bellyboard -drag" discusion.For me it's important the location of the > board >> and I think the place underneath the rearspar is very well chosen ( far >> enough behind the CG ,to give the Kr a small amount of direction stability >> like a dragchute and the waketurbulences does'nt hit the HS !) I 'm >> convinced,a board without holes are more effectiv ( one big > waketurbulence >> produce more drag compared to many small ones). >> I'm also think,a big advantage of the bellyboard is the fact ,that you can >> lower the nose of the Kr on final for better sight( wether you have to > push >> or pull the stik )! >> Herbert >> German Kr builder . >> >> >> Von meinem iPad gesendet >> ___ >> Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. >> To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org >> please see other KRnet info at http://www.krnet.org/info.html >> see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change >> options >> > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options > > > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options --- This email has been checked for viruses by Avast antivirus software. http://www.avast.com
KR> Bellyboard
I know, Mac. Surprising that they didn?t all fall out of the air! Maybe there was little or no airflow separation because the brakes were well clear of the wing surface when fully deployed. Images 29 & 30 here http://www.thunder-and-lightnings.co.uk/vulcan/walkaround.php Mike _ From: Mac McConnell-Wood [mailto:mac.xm657 at gmail.com] Sent: 31 December 2014 13:32 To: Mike; KRnet Subject: Re: KR> Bellyboard Avro's should have read that before designing the Vulcan air brakesfancy putting those solid slabs upwind of the flying controls..! See the pairs of yellow lines indicating position. Regards and a HNY to all our readers Mac On Wed, Dec 31, 2014 at 1:19 PM, Mike via KRnet wrote: A little science from English researchers in 1957 http://naca.central.cranfield.ac.uk/reports/arc/cp/0323.pdf but I'm sure there must be more recent published findings from elsewhere. This suggests that a solid airbrake produces a bubble of reduced airflow behind the brake with airflow velocity fluctuations occurring around the edge of the brake which may cause vibrations to the structure. Perforations in the airbrake reduce this effect and were found to be more effective towards the centre of the plate than around the periphery. >From the Pprune forum, this explanation was offered: "Perforation reduces buffeting downrange of the speed brake, and reduces its interference with flying surfaces or the fuselage or wing or horizontal stab. Remember, the speed brake is there to create drag, but not undesirable flight characteristics. A perforated brake doesn't create nearly the airflow disruption, pitch change, or load on the surrounding and supporting structure that a solid brake might create. The number and placement of holes are important considerations, and part of the design. Holes permit a lighter structure that takes less of an airload, reducing not only the weight of the brake assembly but the force required to actuate it and the structure around it that must support the load. Remember that much of the time, that speed brake isn't anything but dead weight." Mike Mold Devon, UK. -Original Message- From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Mac McConnell-Wood via KRnet Sent: 31 December 2014 10:35 To: Herbert F?rle; KRnet Subject: Re: KR> Bellyboard The RAF Vulcan bomber had solid airbrakes-no holes (which enabled this 90 ton delta to descend vertically-..been there..) Mac On Wed, Dec 31, 2014 at 9:51 AM, Herbert F?rle wrote: > > any Test,however it is performed,gives a lot of informations! The > aerodynamic principles are always the same ,also in the case of the hot" > bellyboard -drag" discusion.For me it's important the location of the board > and I think the place underneath the rearspar is very well chosen ( far > enough behind the CG ,to give the Kr a small amount of direction stability > like a dragchute and the waketurbulences does'nt hit the HS !) I 'm > convinced,a board without holes are more effectiv ( one big waketurbulence > produce more drag compared to many small ones). > I'm also think,a big advantage of the bellyboard is the fact ,that you can > lower the nose of the Kr on final for better sight( wether you have to push > or pull the stik )! > Herbert > German Kr builder . > > > Von meinem iPad gesendet > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options > ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options
KR> Bellyboard
Avro's should have read that before designing the Vulcan air brakesfancy putting those solid slabs upwind of the flying controls..! See the pairs of yellow lines indicating position. Regards and a HNY to all our readers Mac On Wed, Dec 31, 2014 at 1:19 PM, Mike via KRnet wrote: > A little science from English researchers in 1957 > http://naca.central.cranfield.ac.uk/reports/arc/cp/0323.pdf but I'm sure > there must be more recent published findings from elsewhere. > > This suggests that a solid airbrake produces a bubble of reduced airflow > behind the brake with airflow velocity fluctuations occurring around the > edge of the brake which may cause vibrations to the structure. Perforations > in the airbrake reduce this effect and were found to be more effective > towards the centre of the plate than around the periphery. > > From the Pprune forum, this explanation was offered: "Perforation reduces > buffeting downrange of the speed brake, and reduces its interference with > flying surfaces or the fuselage or wing or horizontal stab. Remember, the > speed brake is there to create drag, but not undesirable flight > characteristics. A perforated brake doesn't create nearly the airflow > disruption, pitch change, or load on the surrounding and supporting > structure that a solid brake might create. The number and placement of > holes > are important considerations, and part of the design. Holes permit a > lighter > structure that takes less of an airload, reducing not only the weight of > the > brake assembly but the force required to actuate it and the structure > around > it that must support the load. Remember that much of the time, that speed > brake isn't anything but dead weight." > > Mike Mold > Devon, UK. > > -Original Message- > From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Mac > McConnell-Wood via KRnet > Sent: 31 December 2014 10:35 > To: Herbert F?rle; KRnet > Subject: Re: KR> Bellyboard > > The RAF Vulcan bomber had solid airbrakes-no holes (which enabled this 90 > ton delta to descend vertically-..been there..) > Mac > > On Wed, Dec 31, 2014 at 9:51 AM, Herbert F?rle > wrote: > > > > > any Test,however it is performed,gives a lot of informations! The > > aerodynamic principles are always the same ,also in the case of the hot" > > bellyboard -drag" discusion.For me it's important the location of the > board > > and I think the place underneath the rearspar is very well chosen ( far > > enough behind the CG ,to give the Kr a small amount of direction > stability > > like a dragchute and the waketurbulences does'nt hit the HS !) I 'm > > convinced,a board without holes are more effectiv ( one big > waketurbulence > > produce more drag compared to many small ones). > > I'm also think,a big advantage of the bellyboard is the fact ,that you > can > > lower the nose of the Kr on final for better sight( wether you have to > push > > or pull the stik )! > > Herbert > > German Kr builder . > > > > > > Von meinem iPad gesendet > > ___ > > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > > please see other KRnet info at http://www.krnet.org/info.html > > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to > change > > options > > > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options > > > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options > -- next part -- A non-text attachment was scrubbed... Name: VULCAN b2.jpg Type: image/jpeg Size: 162620 bytes Desc: not available URL: <http://list.krnet.org/mailman/private/krnet_list.krnet.org/attachments/20141231/906b3fb1/attachment.jpg>
KR> Bellyboard
A little science from English researchers in 1957 http://naca.central.cranfield.ac.uk/reports/arc/cp/0323.pdf but I'm sure there must be more recent published findings from elsewhere. This suggests that a solid airbrake produces a bubble of reduced airflow behind the brake with airflow velocity fluctuations occurring around the edge of the brake which may cause vibrations to the structure. Perforations in the airbrake reduce this effect and were found to be more effective towards the centre of the plate than around the periphery. >From the Pprune forum, this explanation was offered: "Perforation reduces buffeting downrange of the speed brake, and reduces its interference with flying surfaces or the fuselage or wing or horizontal stab. Remember, the speed brake is there to create drag, but not undesirable flight characteristics. A perforated brake doesn't create nearly the airflow disruption, pitch change, or load on the surrounding and supporting structure that a solid brake might create. The number and placement of holes are important considerations, and part of the design. Holes permit a lighter structure that takes less of an airload, reducing not only the weight of the brake assembly but the force required to actuate it and the structure around it that must support the load. Remember that much of the time, that speed brake isn't anything but dead weight." Mike Mold Devon, UK. -Original Message- From: KRnet [mailto:krnet-bounces at list.krnet.org] On Behalf Of Mac McConnell-Wood via KRnet Sent: 31 December 2014 10:35 To: Herbert F?rle; KRnet Subject: Re: KR> Bellyboard The RAF Vulcan bomber had solid airbrakes-no holes (which enabled this 90 ton delta to descend vertically-..been there..) Mac On Wed, Dec 31, 2014 at 9:51 AM, Herbert F?rle wrote: > > any Test,however it is performed,gives a lot of informations! The > aerodynamic principles are always the same ,also in the case of the hot" > bellyboard -drag" discusion.For me it's important the location of the board > and I think the place underneath the rearspar is very well chosen ( far > enough behind the CG ,to give the Kr a small amount of direction stability > like a dragchute and the waketurbulences does'nt hit the HS !) I 'm > convinced,a board without holes are more effectiv ( one big waketurbulence > produce more drag compared to many small ones). > I'm also think,a big advantage of the bellyboard is the fact ,that you can > lower the nose of the Kr on final for better sight( wether you have to push > or pull the stik )! > Herbert > German Kr builder . > > > Von meinem iPad gesendet > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options > ___ Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org please see other KRnet info at http://www.krnet.org/info.html see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options
KR> Bellyboard
any Test,however it is performed,gives a lot of informations! The aerodynamic principles are always the same ,also in the case of the hot" bellyboard -drag" discusion.For me it's important the location of the board and I think the place underneath the rearspar is very well chosen ( far enough behind the CG ,to give the Kr a small amount of direction stability like a dragchute and the waketurbulences does'nt hit the HS !) I 'm convinced,a board without holes are more effectiv ( one big waketurbulence produce more drag compared to many small ones). I'm also think,a big advantage of the bellyboard is the fact ,that you can lower the nose of the Kr on final for better sight( wether you have to push or pull the stik )! Herbert German Kr builder . Von meinem iPad gesendet
KR> Bellyboard
The RAF Vulcan bomber had solid airbrakes-no holes (which enabled this 90 ton delta to descend vertically-..been there..) Mac On Wed, Dec 31, 2014 at 9:51 AM, Herbert F?rle wrote: > > any Test,however it is performed,gives a lot of informations! The > aerodynamic principles are always the same ,also in the case of the hot" > bellyboard -drag" discusion.For me it's important the location of the board > and I think the place underneath the rearspar is very well chosen ( far > enough behind the CG ,to give the Kr a small amount of direction stability > like a dragchute and the waketurbulences does'nt hit the HS !) I 'm > convinced,a board without holes are more effectiv ( one big waketurbulence > produce more drag compared to many small ones). > I'm also think,a big advantage of the bellyboard is the fact ,that you can > lower the nose of the Kr on final for better sight( wether you have to push > or pull the stik )! > Herbert > German Kr builder . > > > Von meinem iPad gesendet > ___ > Search the KRnet Archives at http://tugantek.com/archmailv2-kr/search. > To UNsubscribe from KRnet, send a message to KRnet-leave at list.krnet.org > please see other KRnet info at http://www.krnet.org/info.html > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options >
KR> Bellyboard
At 07:19 AM 12/31/2014, you wrote: >A little science from English researchers in 1957 >http://naca.central.cranfield.ac.uk/reports/arc/cp/0323.pdf but I'm sure >there must be more recent published findings from elsewhere. ++ Mike, Thanks for the report. I looked for something similar the other day and found nothing. I guess that settles the discussion and eliminates the need for any additional testing. I doubt if any of our testing would meet the above standards anyway. Looks like flat plate with some holes more to the center to eliminate some unwanted turbulence downstream is the winner. It indicates that a few holes, in the center, do little to harm the drag numbers. My remaining question is the size of the holes in my 9"X30" brake. I'm guessing the answer lies somewhere amongst the X's and O's. Looks like I need to cover some of my perimeter holes and some of you fellows need to cut a few holes in your flat plates. Looks like we were all only half right. :-) Now you builders can get back to building. Happy New Year to all.. Larry Flesner
