Brodhead Pietenpol Association

Original Posted By: flyboy_120(at)webtv.net (Ed G.)
What are you guys doing about rudder control horns? The original Pietdidn't have a steerable tail wheel so it simply had a rudder control horn.With a steerable tail wheel things get complex. Do the control cables stillgo to the rudder horn and then the rudder transfers torque to the tailwheel? Or, do the control cables now go directly to the tail wheel and thenallow the tail wheel to control the rudder? This would seem the logicalsetup. Otherwise a lot of torque would be carried by that little woodenrudder.Thanks,Ted BrousseauWho is finally starting to finish his Piet. See ya in 2003!!________________________________________________________________________________

Original Posted By: Kirk & Laura Huizenga
Subject: Re: Pietenpol-List: Rudder control hornsMost have seperate cables for the rudder and the tail wheel from therudder bar back________________________________________________________________________________Date: Sun, 7 Oct 2001 19:09:25 -0500

Original Posted By: owner-pietenpol-list-server(at)matronics.com
Ted, The manual that Don Pietenpol puts out states that the front rudderspar will not be strong enough to take a steerable tail wheel. I ran twosets of cables back and it works fine. Also, the same manual mentions thatif you use petals instead of the rudder bar, you should beef up the rudderspar as the torque from the petals puts more strain on it.CarlPlease visit my website atwww.megsinet.net/skycarl-----Original Message-----

Original Posted By: owner-pietenpol-list-server(at)matronics.com
Hi Ted,I didn't want to trust the rudder spar to carry all the torque of steeringloads from the horn down to the tailwheel. It was never designed to dothat, and I felt that it would add an awful lot of weight to beef it upenough to do so. I started to do as many others had done and crimp a set oftailwheel steering cables onto the rudder cables so I would get tailwheelsteering directly from the rudder bar. However, the steering arms on mytailwheel were only a couple of inches long, which means that the tailwheelwould be extremely sensitive and quite touchy, particularly on pavement.Discussions with Mike Cuy who uses this arrangement confirmed the problem.I decided to add a couple of fittings on my rudder bar about 6" from thepviot point and attach the tailwheel steering cables there. The onlyproblem was routing them, because if they went straight back, they wouldinterfere with the aileron horns in the rear cockpit. My solution was torout them through pulleys and run them under the floorboard (I had alreadydecided to add a couple of stringers on the belly, which allows room to runthe cables). It makes for a neat arrangement and now the tailwheel reachesits swivel break-over point just before the rudder reaches its stop. I'lllet you know how it works in actual landings in a couple of years.Jack Phillips-----Original Message-----

Original Posted By: owner-pietenpol-list-server(at)matronics.com
Hi Larry,This is another of the many areas left to builder's discretion. This kindof thing makes the Pietenpol more fun to me, trying to come up with the bestpossible design given the constrints you're working within.The FAR's say the seatbelts must be attached to the primary structure. Theyshould be capable of resisting a 20 G impact (beyond that, even if the humanstays in the cockpit, his internal organs will be rearranged), whichtranslates to 20 X the heaviest person you ever expect to put in that seat.Figure on maybe 5,000 lbs of load. Note that the structure doesn't have tosustain this load without deformation - it just can't break completely andlet the occupant go free. I would assume that if you put a 20 G load on theplane, the elongation of the bolt holes holding the seatbelts on will be theleast of your problems.I attached my rear seatblets directly to the lower longerons at the junctionwith the rear seatback, with an AN 5 bolt. This location gives about theright angle for the belt across the lap as shown in Tony Bingelis' books,and this point is as strong as anything on the longeron, since there are twoplywood gussets for the bolt to go through as well as the longeron.For the front seat, I made a couple of fittings of .063" chomoly steel thatattach directly to the ash cross member that spans the rear landing gearstruts. The right fitting mounts on the same bolt as the rudder bar pivotsupport strut with a 5/16" bolt. The left one mounts symmetrically on theash cross member with another AN5 bolt. Both of these bolts pass throughthe ash cross member, the plywood floorboard and the steel strap that runsbeneath the belly.I can send you some pictures if you wish.Good luck,Jack Phillips-----Original Message-----

Original Posted By: owner-pietenpol-list-server(at)matronics.com
What do you guys think of this idea for routing the tail wheel steeringcables?On the lower cross member of the first bay behind the rear seat (ie justunder the elevator bell crank) put in a "horizontal bell crank", almost likeanother rudder bar full length across the fuselage. Connect the cables fromthe rudder bar and the rudder to it, so it swings freely with rudder action.Then about 4 inches from the center point, connect the steering cables.This piece could be made fairly light since it doesn't carry much load. Andthe slight added weight would be offset by less cable from the front. Thiswould desensitize the steering action, and would avoid the problem ofrouting the steering cables past the aileron control horn or under thefloorboards.I haven't tried it yet, still just a thought. See any problems with this?Al Swanson-----Original Message-----

Original Posted By: owner-pietenpol-list-server(at)matronics.com
No problem other than extra weight aft of the CG.-----Original Message-----

Original Posted By: Kirk & Laura Huizenga