Avro's should have read that before designing the Vulcan air brakes....fancy 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 <krnet at list.krnet.org> 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 > -------------- 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>
