KR> anyone using a redrive on small VW engine
On Mon, Apr 27, 2015 at 5:47 PM, bjoenunley via KRnet wrote: > Building a belt driven psru seems doable. Has anyone here built one or plan > to build one? > > Joe > Florida > > "current available redrives for the vw seem to be heavy and/or > unreliable. most would find the engineering cost to optimise redrives" > > yes it is but you have to make compromises. if i have to use a belt i would use a standard weight flywheel from the flyhweel end and 1 inch shafts to and from the belt drives. even a couple v belts will do. i would prefer the newer toothed belt in oil and plain bearings myself. i would still prefer a properly designed geared redrive with a fully counterweighted cross plane crank. the gears and flywheel don't need to be as heavy and i can use a turbo. if you don't want the flywheel then its more difficult. you have to handle harmonics between the prop and the large positive and negative torque pulses from the crankshaft. if you take power from the crank nose then thats way too hard already. the belts will self destruct no matter how heavy you make them. same for chains. even the heaviest gears will not survive the chatter from the backlash between the prop and crankshaft torque pulses. people have tried various clutches, viscous drives, rubber balls etc. they all end up heavier. thats why people who drive the prop from the wrong end always use a force 1 bearing and only wood props at normally aspirated, derated rpm tune only.
KR> anyone using a redrive on small VW engine
On Mon, Apr 27, 2015 at 6:43 AM, Chris Prata via KRnet wrote: > I wondered about that too. A redrive has other benefits as well of a larger, > slower turning propeller. First, much stronger takeoff acceleration and also > climb. Quieter too. > Hopefully some good replies and examples will be forthcoming... > Hi, current available redrives for the vw seem to be heavy and/or unreliable. most would find the engineering cost to optimise redrives to be prohibitively expensive. this is primarily due to torsional vibration issues. the flat 4 flat crank engine has the most horrendous torque pulses imaginable. it takes a heavy flywheel to tame them and that turns turns off most builders.
KR> Kr1 ssdr variant
I just discovered the uk single seat deregulated category. 390 kilo mtow for amateur build and 35 MPH stall. That's it! Just a claim from the pilot that it meets the excemptions and a microlight license and you go flying! Im building the carbon spar wing after all...
KR> UK aircraft grade lumber supplier?
Im planning to use the cf for the main spar and a second spar at 50% chord, wing skins and ailerons and flaps and landing gear. But im going to build a stock kr2 for now. I was trying to copy the colomban mc 100. high wing loading (about same as a cessna!). small wetted surface area and light weight. the gear needs to be taller to accommodate the flaps. which is composed of a fowler flap under a plain flap, and it needs to be very torsionally rigid so i can actuate it reliably from the fuselage. And the wing root needs to be 5.4 inches thick using a different 15 % airfoil. On Mon, Mar 2, 2015 at 12:09 AM, Flesner via KRnet wrote: > At 06:02 PM 3/1/2015, you wrote: >> >> I just ordered flat tow bid uni and triax carbon fiber fabric for my >> spars. > > ++ > How are you planning to use carbon fiber on the spars? The plans call for > spruce and ply only. > > Larry Flesner > > >
KR> UK aircraft grade lumber supplier?
On Tue, Mar 3, 2015 at 12:12 PM, Rogelio M. Serrano Jr. wrote: > > Spruce is like Gold nowadays. Which is a good substitute? Baltic Pine? > bald cypress? > > Anybody got a stand of stika spruce they can spare? ;-) > Half of commercial plantations in the UK actually plant Sitka Spruce. But they are mostly used for paper, furniture and packing crates. Packing crates!
KR> UK aircraft grade lumber supplier?
Ill build it stock for now. On Mon, Mar 2, 2015 at 8:48 AM, JAMES DUFF wrote: > As Mike says. > > If you're flying under UK law it needs to be built as per plans which is > what the design has been assessed against, unless it's a KR2S in which case > it's as per plans plus some mandatory modifications which the LAA will send > you drawings of. > I will do that later. > It is possible to modify from the plans, but mods need to be approved via a > documentation package demonstrating by calculation their safety and > integrity. Structural mods will also require physical load testing. > > Dudley Pattison of the Swindon Aircraft Timber Company was good, but I hear > he's trying to retire. > Spruce is like Gold nowadays. Which is a good substitute? Baltic Pine? bald cypress? Anybody got a stand of stika spruce they can spare? ;-) > If built under UK law it needs to be built with Sitka Spruce and GL1 grade > birch ply. You can use GL2 ply for non-structural stuff, but I can't think WOW! That Law needs to be changed! > of anything non-structural on a plans-built KR2 off the top of my head. > > I would most strongly suggest you heed Mike's advice and contact the LAA for > advice before proceeding any further. > > Regards, > > Jamie >
KR> UK aircraft grade lumber supplier?
On Mon, Mar 2, 2015 at 10:34 AM, Dan Heath via KRnet wrote: > So, I guess that if you were to build a "one-up", it would be as bad as > building a new certified aircraft here in the US. Seems like a really good > way to encourage "experimentation". > Its not that bad really. But I think ill consider flying to the US and build a cf wing there... Don't know if i could fly it back here though...
KR> UK aircraft grade lumber supplier?
Hi Peter, Thank you for the heads up. I got so excited about the CF i forgot about the LAA. What mods are you doing exactly? On Mon, Mar 2, 2015 at 11:24 AM, Peter Drake wrote: > Hi Rogelio > > I am based in Herefordshire and am building a much modified KR2s > (www.peterskr2s.co.uk) > DO NOT MAKE MODIFICATIONS LIGHTLY AND WITHOUT APPROVAL FROM LAA ENGINEERING, > you will encounter big hassles if you do and you will not get a permit to > fly without. > I am speaking from personal experience! > > Getting spruce in the UK is difficult. However I have found a source in > Oxfordshire called Bygone Aviation near Witney. (Matt at bygoneaviation.com). > > Give me a call on 01497 847340 if you want a chat. > > Cheers > > Peter Drake >
KR> UK aircraft grade lumber supplier?
Hi Mark, That means individuals cannot do it alone anymore. On Tue, Mar 3, 2015 at 3:13 AM, Mark Langford via KRnet wrote: > > So yes, carbon fiber spars will almost certainly require more work than you > can imagine to get past Engineering. The few pounds you will save in the > effort will likely cost years and thousands of BP. But some people enjoy > the chase and the sense of accomplishment at pulling it off, so feel free to > blaze a trail for us... > I designed a small wing with big flaps. Actually double flaps and it needs the rigidity of carbon fiber to work. The root chord is 38 inches and the tip is 24 inches. Wood just doesnt cut it for a max gross of 900 lbs and a load factor of 7 G. A quarter inch thick 4 inch wide cf spar cap is already overkill and that's way lighter than wood. Besides Sitka Spruce is already approaching the price of Gold. Its sustainable and all but nobody plants them anymore. The fuselage need to be taller. The elevator needs to become a stabilator. The vert needs to become an all moving rudder, Like the Vee pee. The front fuse need to be shorter and straighter, 41 inches wide and parallel to the firewall. And the landing gear leg needs to be cf and really light and out of the prop wash. The game changer for me in terms of carbon fiber is the flat tow fabrics and reduced cost of triax. Its way better than the earlier fabrics.
KR> UK aircraft grade lumber supplier?
Hi Peter, Doing it alone is very very hard. On Tue, Mar 3, 2015 at 8:52 AM, Peter Drake via KRnet wrote: > Mark > I thought I enjoyed a chase, but that one is wearing a bit thin now! > > Peter Drake >
KR> UK aircraft grade lumber supplier?
> How are you planning to use carbon fiber on the spars? The plans call for > spruce and ply only. > > Larry Flesner I am deviating from the plans. I hope it will not be too much of an issue.
KR> UK aircraft grade lumber supplier?
Hi Guys, I hope UK based builders can get in touch. I live in the Isle of Man and I'm looking for spruce and okoume plywood suppliers in the northwest of Britain. I just ordered flat tow bid uni and triax carbon fiber fabric for my spars. I hope to be building the fuse as soon as possible. Thank you in advance.
KR> Spar and WAF stress analysis
That's nice to know... Thanks! On Feb 24, 2015 12:39 PM, "Herbert F?rle" wrote: > > the conclusion of the German Test of the Kr Spar and WAF's calculated by Otto Bartsch is: Any reliable built Kr with a MTOW of 1050 pounds is a 4,2 G's plane with a 1,45 safety factor,or a 3,8 G 's x 1,6 plane! > Otto Bartsch assured me,that the calculation was carried out somewhat conservative ! > Herbert F?rle > German Kr > 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> center spar analysis
Based on a section modulus of 18.5 in3 and yield strength of spruce at 5000 Psi, the center spar should yield at 92500 lb in. bending moment. I don't know how that translates to wing load. On Feb 22, 2015 4:58 PM, wrote: > > Just an idea. We have a gathering coming up in September. I would imagine there is a set of fwd spars lying around gathering dust somewhere. If we can get them to McMinnville with some sandbags and do our on test. I would be willing to pitch in to help defray the cost. > > I might be able to talk to Eric at Wicks to donate some of there scrap spruce if someone would like to build a AS5048 Spar. We would just need a center and one outboard spar. > > Paul Visk > Belleville Il. > 618-406-4705 > > In a message dated 2/22/2015 10:23:07 A.M. Central Standard Time, krnet at list.krnet.org writes: >> >> On Sun, Feb 22, 2015 at 1:29 AM, Flesner via KRnet wrote: >> > >> >> >> >> The Spreadsheet says we should be using aluminum spars to make more >> >> than 2G load factors. >> > >> > >> > >> > It's been a long held belief that the WAF's were the weak point in the KR >> > spars. I've had the opportunity to inspect 3 crashed KR's, unfortunately >> >> both front and rear spars together can easily take 3.8G at 1200 lbs >> mtow. but thats a rough calculation. i'm actually overestimating the >> stresses because tapered wings have more or less 10% lower bending >> moments than rectangular wings overall. I was assuming a rectangular >> wing. >> >> a more accurate computation will require more accurate load >> distributions with flap and aileron deflections considered. only >> shrenk's approximation and similar procedures can do that. >> >> ___ >> 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> center spar analysis. Just an idea. (Repost sorry)
That would be great! On Feb 22, 2015 6:07 PM, "Paul-Visk via KRnet" wrote: > > > Just an idea. We have a gathering coming up in September. I would imagine > there is a set of fwd spars lying around gathering dust somewhere. If we > can get them to McMinnville with some sandbags and do our on test. I would > be willing to pitch in to help defray the cost. > > I might be able to talk to Eric at Wicks to donate some of there scrap > spruce if someone would like to build a AS5048 Spar. We would just need a > center and one outboard spar. > > Paul Visk > Belleville Il.
KR> center spar analysis
On Sun, Feb 22, 2015 at 1:29 AM, Flesner via KRnet wrote: > >> >> The Spreadsheet says we should be using aluminum spars to make more >> than 2G load factors. > > > > It's been a long held belief that the WAF's were the weak point in the KR > spars. I've had the opportunity to inspect 3 crashed KR's, unfortunately both front and rear spars together can easily take 3.8G at 1200 lbs mtow. but thats a rough calculation. i'm actually overestimating the stresses because tapered wings have more or less 10% lower bending moments than rectangular wings overall. I was assuming a rectangular wing. a more accurate computation will require more accurate load distributions with flap and aileron deflections considered. only shrenk's approximation and similar procedures can do that.
KR> center spar analysis
> Im studying beam theory and i wanted to see if i understood the math. >> I was trying to see how the design is doing with the latest take off >> weights. >> I'm surprised by the results. >> Thank you Mark! > > +++ > > Surprised good or surprised bad? Inquiring minds want to know. Marty > Roberts did his share of real world testing and lived to tell about it. My > hero. :-) The Spreadsheet says we should be using aluminum spars to make more than 2G load factors. That cant be right. Maybe because i'm using google docs to view the spreadsheet. Or maybe the spreadsheets are just not meant to handle full blown planes. Have you guys tried it out yet? I got the beam theory right but the load distributions are wrong. I really need to dig into Shrenk's Approximation seriously this time.
KR> center spar analysis
On Sat, Feb 21, 2015 at 7:00 PM, Chris Prata via KRnet wrote: > What is this about, calculating spar strength? > Does address attach fitting too? (Although I believe I saw a video that they > break after the spar?) > Im studying beam theory and i wanted to see if i understood the math. I was trying to see how the design is doing with the latest take off weights. I'm surprised by the results. Thank you Mark!
KR> OT: heat rejection capacity from exhaust port walls
On Feb 12, 2015 3:11 PM, "Dan Heath via KRnet" wrote: > > Yes, keep the heat in the pipe. This is good for many reasons. Get your pipes coated inside and out, or do it yourself. I had Jet Hot do mine and I believe that Mark L. does his. > > That's very interesting. Is it enough to keep head temps below 160 c? How durable are the coatings? Thanks!
KR> OT: heat rejection capacity from exhaust port walls
Hi, Slightly OT but i don't know where to ask. Is heat absorption from exhaust port walls more significant than that absorbed from chamber walls? That means if we don't alter anything else but reduce absorption, can we see a significant drop in cylinder head temps? Maybe an effective thermal barrier coated exhaust port makes a difference? Anybody tried that yet?
KR> Taxi testing
i don't get it guys... expert test pilots just taxi to the runway then push the throttle to the wall and take off? On Wed, Feb 4, 2015 at 5:33 PM, n357cj via KRnet wrote: > Well Guys, I was trying to stay away from this subject but I have yet to see > one of the compelling reasons to do taxi tests with a brand new experimental > airplane. What is wrong with the plane??? There a any number of things that > can seriously kill ya that could be wrong with your plane. I did nearly 10 > hours of running the runway. I discovered brake problems, throttle sticking, > a carb that could not handle ram air. They were resolved and I didn't have to > worry about them for the actual first flying which went off uneventful. I > also tend to think that this conversation is assuming always to fast taxi > and that is not always the case either and should be treated as a gradual > learning event. > Joe Horton > > - Original Message - > From: "Herbert F?rle via KRnet" > > > ...I'm absolutely the opinion of Marks recommendations! > Any theories,which can be read in books and magazines are good for the head > but not for the hands.Therefore,it is essential to coordinate theory and > practice.As Mark said,it is very controversial to find a suitable human/Pilot. > Before I flew my Kitfox the first time,I faced the same decision.I completet > about fifty landings in a citabria with a very experienced > instructor,reminded me on my successful take offs with my Fisher Koala and > last but not least on the countless flights with a taildragger motorglider > .This whole experience- package caused me to be my own testpilot,Tanks > good,with success! > I have no fear , to do it again with my Kr! > Herbert Fuerle > German Kr2s > 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> Fuel injection - megasquirt
On Wed, Jan 28, 2015 at 9:22 PM, Tony King via KRnet wrote: > Rotax has clearly decided EFI is the way to go. But have you seen the > complexity of their implementation on the 912iS? Running an EFI like > Megasquirt or SDS in an aircraft can and has been done, but it introduces a > lot of new failure modes that you need to understand and make a conscious > choice whether to address them or live with them. And addressing them > equals time and (frequently) complexity. That's fine if that's your thing, > and the results should be a smoother running and more economical engine. > But don't underestimate the effort required to get it working well and > reliably. > > I'd love to put EFI on my KR2S when I get to setting up the engine. But > I'd rather fly than tinker, so I probably won't. > > Cheers, > > Tony > Collaboration will make it easy to set up. The biggest threat to these systems are heat and moisture. when protected properly they are very reliable. So much so that even single plug per cylinder systems are almost bulletproof. > On 29 January 2015 at 06:13, Chris Prata via KRnet > wrote: > >> >> I'm just throwing this out here to see if fuel injection as a way to move >> past carb issues, get more precise fueling and better performance is >> happening on KR's. >> Personally, I'm looking (hoping) to build a near-original KR1, and keep it >> as simple as possible (other than a possible retractable tri-gear, >> in-flight adjustable prop, belted redrive, and turbocharger system, and >> full autopilot, LOL). >> Anyway, here is the megasquirt info: >> http://www.msextra.com/ >> >> -Chris >> > ___ > 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
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 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
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 >
