KR> Rudder Stops
The 150/152 rudder stops on the rudder horn was in response to loss of control issues during training specifically spin training The original stops were much smaller and could jump over the adjustment stop resulting in jammed rudder and several deaths Regarding stress on cables as a former 152 owner I put enough stress on the rudder stop once In a cross wind landing I should not have attempted that I bent a pulley bracket The A stated the cable was fine and just repaired the bracket Looking back on it now maybe he did not want to rerun the rudder That was my experience Gary
KR> rudder stops
At 09:35 AM 6/9/2015, you wrote: >I've had wire cables fail two ways for me. One way, is where the >crimp/soldered end/etc tears off the end of the cable. I think I've had >that happen three or four times over my lifetime. The other failure I've >had is midpoint wire breakages. ++ I certainly hope we builders are building and testing to a higher standard than you have experienced with your bike cables. As builders we should be using a quality cable and testing all connections before installing in the aircraft. In addition, my cables are inspected each year for integrity and tension, as well as all attach points, fare leads, pulleys, etc. With that in mind, I'm certain that on my tail dragger I would put much more stress on the rudder cable system when I go full travel on the rudder pedal and then depress the toe brake to do a 180 degree turn on the ramp if my stops were at the rudder instead of at the pedal. I built my system to try to eliminate what I considered the most likely failure mode. As no system is fail proof, build it the way that makes you comfortable, inspect carefully, and take your chances. Do your best to anticipate any failure modes and design them out of the system or have antiquate backup. Larry Flesner
KR> rudder stops
I'm about to make an argument for stops at the surface only. I think I've got a good argument here. I've had wire cables fail two ways for me. One way, is where the crimp/soldered end/etc tears off the end of the cable. I think I've had that happen three or four times over my lifetime. The other failure I've had is midpoint wire breakages. As we all know, wire rope doesn't stretch beyond taking it's initial set. Three times I've had wires start stretching on me. Two were brake cables, and the third was a throttle cable. In all three situations I was able to stop the bike, and control the bike, in spite of the control cable lengthening due to available over travel in the control. eg: brake levers that had more travel before they hit the bar, and a throttle tube that could turn another 1/4 turn beyond full throttle. If there were stops built into the brake lever, or throttle tube, instead of stops on the calipers and carburetors, I'd have been left with no brakes, or stranded on the highway. This is the same reason the throttle spring on your carburetor is at the carb, instead of the control cable. If the control fails, the system is safe without it. If your rudder doesn't have stops at the control surface, if something happens to the control wire, you could end up with rudder interference with the elevator, or other damage. Okey, so lets try something else. Lets say your fairlead fails, or a cable hops off a guide bearing, and your control wire now has 3" more length in it. If you have your stops at the control, you now have sufficient slop in your system that you have no control over those surfaces. If you don't have stops, there's some chance that by going to the extremes of your control range that you could still have some authority on which way those surfaces go. That's my argument for not having stops at the control itself. ... I didn't actually have a serious opinion on this until I thought about it last night. Definitely stops at the surface. Not at the control. On Tue, Jun 9, 2015 at 8:12 AM, Flesner via KRnet wrote: > > >> "Hey Guys, Looks like I'll be doing Rudder stops as an afterthought. >> What's the best place and method for this ?" >> > > + > > When it comes to stress loads on the control systems in my KR, I'm > convinced the greatest source would be if the control surfaces are stopped > and the input end is capable of additional input, especially the rudder > system. My rudder pedals are spring loaded to the firewall to center / > tension the cables. My rudder does no flop back and forth on the ground as > a Cessna or RV would do as their cables go slack without the pilot's feet > on the rudder pedals. If the wind is moving the ailerons or elevator on > the ground, it seldom does, I can lock them with the seat belt to the > stick. There is no way to eliminate air loads on the system in flight but > they are very light and have nothing to do with system stops as the > surfaces only move a few degrees in normal flight mode. I can't imagine a > flight condition where the air loads on the surfaces will overpower pilot > input and the surface would contact a stop at the control surface. The > only time control stops are an issue is at maximum deflection which is > seldom. Where are the system loads originating from at that point, the > control surface or the input end? > > Consider your system setup and put the stops where you think best. I'm > convinced the pilot is capable of stressing the system more than any flight > loads so my stops are on the input end. As always, your results may vary. > :-) > > Larry Flesner > > ___ > 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> rudder stops
> >"Hey Guys, Looks like I'll be doing Rudder stops as an afterthought. >What's the best place and method for this ?" + When it comes to stress loads on the control systems in my KR, I'm convinced the greatest source would be if the control surfaces are stopped and the input end is capable of additional input, especially the rudder system. My rudder pedals are spring loaded to the firewall to center / tension the cables. My rudder does no flop back and forth on the ground as a Cessna or RV would do as their cables go slack without the pilot's feet on the rudder pedals. If the wind is moving the ailerons or elevator on the ground, it seldom does, I can lock them with the seat belt to the stick. There is no way to eliminate air loads on the system in flight but they are very light and have nothing to do with system stops as the surfaces only move a few degrees in normal flight mode. I can't imagine a flight condition where the air loads on the surfaces will overpower pilot input and the surface would contact a stop at the control surface. The only time control stops are an issue is at maximum deflection which is seldom. Where are the system loads originating from at that point, the control surface or the input end? Consider your system setup and put the stops where you think best. I'm convinced the pilot is capable of stressing the system more than any flight loads so my stops are on the input end. As always, your results may vary. :-) Larry Flesner
KR> rudder stops
"Hey Guys, Looks like I'll be doing Rudder stops as an afterthought. What's the best place and method for this ?" I don't often contribute but I think this time it is important. My take on this is; I am installing stops at both ends. The reason: I hear it is accepted good practice to stop the control surface, and the force in the control cable is exactally the same at any point in the system. does the force originate from your foot or the airodynamic force on the rudder? Which is the applied force and which is the reaction makes no difference to the components. For the usual KR style rudder peddle assembly, if the horn is stopped and the peddle still has travel there will be a high amount of torque applied to the peddle assembly. That is how mine failed. The pilot applied more right rudder force that was effectivly needed (not hard to imagine in a stressful situation). The horn stopped but the peddle continued for another half inch or so and the miter joint on the peddle assembly snapped. The resulting ground loop provided an opportunity to redesign the landing gear, I never did like that design. nothing was bent on the peddle assembly so I simply welded it back together and added a wrap around gusset with the welds in shear increasing the torsion stength many time over but now the added torsional strength is mostly redundent because the peddle assembly will not be loaded in torsion any more than would be applied by normal aerodynamic rudder load (or is that foot force?). That's my story and I'm stickin to it. Pete Gauthier KR Builder Woodburn, OR
KR> rudder stops
The highest loads you'll ever put on your rudder cables and rudder horn are when you are braking if you have toe brakes. The Tony Bingelis books advise using stops at the control surfaces to prevent overload and damage at the control surface hinges when parked with a tailwind, should you happen to do a tail slide, or for any other reason that your controls might be loaded or pushed from behind. The KR series of aircraft are a bit unique in that the builders manual does not recommend the use of control stops. If I remember correctly, it doesn't mention them. I don't know how that could happen with such a high quality modern builders manual. (sarcasm implied) -Jeff Scott Los Alamos, NM > Ever look at a Cessna? > The control stops are at the control surfaces to prevent over stressing the > surface due to flight loads, not pilot input. > Just sayin' > Chris G. > > Sent from my iPad > > > On Jun 7, 2015, at 10:00 PM, Flesner via KRnet > > wrote: > > > > At 08:52 PM 6/7/2015, you wrote: > > > >> I would disagree with Larry on that one. > >> The control surface stops should be as close to the control surface as > >> possible. > > ++ > > > > Why do I want to stress the entire system, cable, fare leads, pulleys, and > > rudder horn when I go to full travel and then add additional pressure? My > > stops are at the input end while ensuring full travel at the control > > surface. My aileron and elevator stops are at the stick. > > > > Larry Flesner > >
KR> rudder stops
That looks like the missing piece of info that I was wondering. I suppose nothing stops one from having both, and I wonder if that would be prudent. I could relate to the comments about over stressing the cable and pulleys and in a adrenaline situation we may not be self-aware and push the foot too hard. So it looks like we have a reason for something to protect the flight surface from banging over too far, and also the control cable and related from being stressed. Why not both? > Date: Mon, 8 Jun 2015 13:02:04 -0400 > To: krnet at list.krnet.org > Subject: Re: KR> rudder stops > From: krnet at list.krnet.org > CC: cgardn628 at rogers.com > > Ever look at a Cessna? > The control stops are at the control surfaces to prevent over stressing the > surface due to flight loads, not pilot input. > Just sayin' > Chris G. > > Sent from my iPad >
KR> rudder stops
Ever look at a Cessna? The control stops are at the control surfaces to prevent over stressing the surface due to flight loads, not pilot input. Just sayin' Chris G. Sent from my iPad > On Jun 7, 2015, at 10:00 PM, Flesner via KRnet > wrote: > > At 08:52 PM 6/7/2015, you wrote: > >> I would disagree with Larry on that one. >> The control surface stops should be as close to the control surface as >> possible. > ++ > > Why do I want to stress the entire system, cable, fare leads, pulleys, and > rudder horn when I go to full travel and then add additional pressure? My > stops are at the input end while ensuring full travel at the control surface. > My aileron and elevator stops are at the stick. > > Larry Flesner > > ___ > 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> rudder stops
KR> rudder stops
At the rudder pedals, Virg On 6/7/2015 7:01 PM, Mike Sylvester via KRnet wrote: > Hey Guys, Looks like I'll be doing Rudder stops as an afterthought. What's > the best place and method for this ? > > Mike Sylvester > kr2s builder > Birmingham,AL. > > Cell no.205-966-3854 > ___ > 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> rudder stops
I would disagree with Larry on that one. The control surface stops should be as close to the control surface as possible. It is a Canadian requirement to have control stops on all control surfaces. My rudder stops are where the control horn meets the fuselage. A simple bracket was added with adjustable stop bolts to contact the horn. Pix on request. Regards Chris Gardiner KR2S 240 hours CGKRZ Sent from my iPad > On Jun 7, 2015, at 8:48 PM, Flesner via KRnet wrote: > > > >> , Looks like I'll be doing Rudder stops as an afterthought. What's the best >> place and method for this ? >> Mike Sylvester > ++ > > Method will depend on your setup but put them at the rudder bar and not on > the tail. You don't want to stress the entire system if you go full rudder > to the stop. > > Larry Flesner > > ___ > 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> rudder stops
At 08:52 PM 6/7/2015, you wrote: >I would disagree with Larry on that one. >The control surface stops should be as close to the control surface >as possible. ++ Why do I want to stress the entire system, cable, fare leads, pulleys, and rudder horn when I go to full travel and then add additional pressure? My stops are at the input end while ensuring full travel at the control surface. My aileron and elevator stops are at the stick. Larry Flesner
KR> rudder stops
>, Looks like I'll be doing Rudder stops as an afterthought. What's >the best place and method for this ? >Mike Sylvester ++ Method will depend on your setup but put them at the rudder bar and not on the tail. You don't want to stress the entire system if you go full rudder to the stop. Larry Flesner
KR> rudder stops
Hey Guys, Looks like I'll be doing Rudder stops as an afterthought. What's the best place and method for this ? Mike Sylvester kr2s builder Birmingham,AL. Cell no.205-966-3854
