KR> Belly board
I flew a few hundred hours both ways and the holes did seem to form more drag. Sparky Sparks Sent from Windows Mail From: Kenneth Wiltrout via KRnet Sent: ?Friday?, ?December? ?26?, ?2014 ?3?:?23? ?PM To: KRnet I tested the board both ways. The holes seem to help slow it down.Kenny WiltroutN6399U On Friday, December 26, 2014 12:47 PM, Dan Branstrom via KRnet wrote: I always wondered about the holes in a belly board. The T-28s I flew had them on the belly mounted speed brake that was flush with the fuselage when retracted. I could only imagine that the holes gave it greater drag because of conflicting vortices generated by the holes. At the KR gathering, I noticed that our British friend had holes in his belly board. I've noticed that the speed brakes on jets don't have the holes. Even retracted, they cause some disruption of the airflow because the surface is not smooth because of the holes. At the higher speeds of jets, since parasitic drag goes up as the square of the speed, holes like that could significantly add drag. A T-28 usually cruised at about 200mph. That's just about the approach speed of jets. Of course, as home builders, by using foam and fiberglass, bumps made on the belly could fill the holes retracted, but at the speeds of a KR, the drag caused by the retracted speed brake may not be significant. Dan Branstrom ___ 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> Belly board
I tested the board both ways. The holes seem to help slow it down.Kenny WiltroutN6399U On Friday, December 26, 2014 12:47 PM, Dan Branstrom via KRnet wrote: I always wondered about the holes in a belly board.? The T-28s I flew had them on the belly mounted speed brake that was flush with the fuselage when retracted.? I could only imagine that the holes gave it greater drag because of conflicting vortices generated by the holes. At the KR gathering, I noticed that our British friend had holes in his belly board. I've noticed that the speed brakes on jets don't have the holes. Even retracted, they cause some disruption of the airflow because the surface is not smooth because of the holes.? At the higher speeds of jets, since parasitic drag goes up as the square of the speed, holes like that could significantly add drag.? A T-28 usually cruised at about 200mph.? That's just about the approach speed of jets. Of course, as home builders, by using foam and fiberglass, bumps made on the belly could fill the holes retracted, but at the speeds of a KR, the drag caused by the retracted speed brake may not be significant. Dan Branstrom ___ 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> Touchdown Speeds?
What kinds of speeds are people using to land their KRs? Jones just wrote ". and when the wheels touch the pavement I am doing 70 MPH ." That seems fast, no? Trying to reduce my PIOs on short final. John Bouyea N5391M/ KR2 OR81/ Hillsboro, OR
KR> Belly Board
YHa. I just returned from a 1.2 hour flight around Steven Point, WI. This was my first flight since 10/25 due to our shi&&y weather we have up here. So what does this have to do with belly boards? Here is how I use mine in the landing sequence. I called left downwind 21 Stevens Point and reduced my speed to 125 MPH. Next I called turning left base 21 Stevens point and am now at 120 MPH. I maintain that speed through base and call turning final 21 Stevens Point. I pull back the power to slow her to 115 and drop the belly board to full down position. At this point I would estimate I am now at 1/4 mile final and slowing fast. I cross the numbers looking at 80 MPH and when the wheels touch the pavement I am doing 70 MPH and she sets down smooth a silk. The following are two links. The first is the web link to the construction of my solid belly board. The second is a landing video on runway 21 Stevens Point and note you can see the speed brake being lowered. Also note the minor deflection of the gear with touchdown and that is loaded up with two people on board. Belly Board web link: http://www.flykr2s.com/bellyboard.html Landing video: https://www.youtube.com/watch?v=pfXagjar5IE Mark Jones (N886MJ) Stevens Point, WI E-mail: flykr2s at charter.net Web: www.flykr2s.com
KR> Belly board
I always wondered about the holes in a belly board. The T-28s I flew had them on the belly mounted speed brake that was flush with the fuselage when retracted. I could only imagine that the holes gave it greater drag because of conflicting vortices generated by the holes. At the KR gathering, I noticed that our British friend had holes in his belly board. I've noticed that the speed brakes on jets don't have the holes. Even retracted, they cause some disruption of the airflow because the surface is not smooth because of the holes. At the higher speeds of jets, since parasitic drag goes up as the square of the speed, holes like that could significantly add drag. A T-28 usually cruised at about 200mph. That's just about the approach speed of jets. Of course, as home builders, by using foam and fiberglass, bumps made on the belly could fill the holes retracted, but at the speeds of a KR, the drag caused by the retracted speed brake may not be significant. Dan Branstrom
KR> Belly Board
Keep it up and somebody's going to make a pair of matching boards, one solid and one perf'd, and run a comparison test ;o) Oscar Zuniga Medford, OR
KR> Belly Board
> I can't image more deflection than with a solid piece I don't follow the "more deflection" line of thought. Do you mean "more drag" ? I've always had a gut feeling the holes created more drag if the Navy used them. My advise is : on the heavier KR's, 700 pound range, go with a 9 inch by the width of the fuselage, put holes in it, and get it to deflect to as near 90 degrees as possible. http://myplace.frontier.com/~flesner/19.jpg Say fellow, that's some nice looking holes you have there... Larry Flesner
KR> Dipole Antenna
On 12/25/2014 10:50 PM, Sid Wood via KRnet wrote: > Any dipole antenna design that requires ferrite toroids is wasting > transmitter power due to the mismatch between the rf cable and the > antenna elements. Maybe so, but Jim Weir has been advocating this design for probably 30 years, lots of them are flying in KRs and many other glass airplanes, and they work just fine. Joe Horton and I have both talked up to 200 miles apart on a quiet frequency, and that's good enough for me. The beauty of this design is that it weighs practically nothing, costs practically nothing, can be built at home in a matter of minutes, fits perfectly into space that is otherwise empty on the KR, and it WORKS. If it's wasting a little energy, I'm fine with that...it's good enough for KR work. If the concern is that it's difficult to get the antenna kit anymore, that's easily solved by somebody buying a few 100' rolls of copper foil tape and a bag of toroids, and selling those kits themselves. But my guess is that Jim doesn't just sit on these orders for several weeks before he ships them...he probably went on vacation or got stuck in the hospital or was indisposed in some way that put a hitch in the orders for a while, but I doubt this is the usual mode of operation. Mark Langford ML at N56ML.com http://www.n56ml.com
