Normal means perpendicular. Its just a mathematical term.
On Jan 1, 2015 7:05 PM, "gluejam via KRnet" <krnet at list.krnet.org> 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 <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 > > > > > --- > This email has been checked for viruses by Avast antivirus software. > http://www.avast.com > > _______________________________________________ > 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
