Brodhead Pietenpol Association

Original Posted By: Steve Eldredge
Jim Skinner wrote:>Yes, bungee failures do happen. Oil from the engine doesn't help andcovers are available to keep the oil>off of them. A limit bolt or cable is REQUIRED!Heartily agree.>>If you do go this route, I would suggest not running the>bungee struts to the opposite side of the fuselage. This creates avery flat triangle when the bungee is>stretched on a hard landing. Making a yoke so that both sidescan be anchored to the yoke on the>centerline of the fuselage is MUCH stronger.Not sure I agree with the implication here.I know of one Air Camper that just tested the gear to destruction, (twoweeks ago) and it had the Vee frame as yoiu describe, andeveryone there suggested going to the cross version. (not sure I agreehere either, see final comments) Same arrival sequense BTW ie bounce,second arrival at obtuse angle, gear gives way, wing tip, prop, and geardamage.> I know this from experience. Was a passenger in a Piet with>this type of gear landing in a strong crosswind. The plane bounced andweathervaned into the wind. The>cable used for the throttle was a stranded cable (like a motorcyclethrottle cable) but under compression.>(We did not build the plane and were unaware of this item at the time)The cable colapsed when the pilot>tried to open the throttle. The plane came down slightly tipped to oneside. That side gear stretched the>limit bolt enough to pop over center.I cant picture what this means or how it would happen. IN both splitgear setups with or without the Vee, the bungee strutsneed to have limits. the travel is only about 3 inches on each strut.I have secured mine with 1/8" ss cable looped around thebungee wrap tubes. My guide tube (the one that slides inside the strutsto keep both alligned) allows much more travel (9 inches).> The wheel ended up resting against the wing strut and the prop tips>plowed the turf. A number of people came out and held up that side toroll the plane off the runway.>Partway back someone pushed on the wheel and it popped back down intoit's normal position! We were then>able to put the full weight of the airplane on the gear. Repairsincluded switching to the yoke type gear>attachment, replacing the throttle cable with a solid wire, and proprepairs. It is hard to say what might>have happened if the gear had held up. The damage could easily havebeen worse. I always suspected that>tighter limit stops (allowing less travel) MIGHT have helped the gearproblem but the yoke is even better. FINAL COMMENTSAfter seeing the damage to the gear and inspecting the failedconnection, I discovered that the gear strut end bolt sleeve was onlyspot welded and the force of the side load caused the metal to tearthrough. The bungee hit the limit cable and the strut failed. Thesolution in Jimmy's story was a tighter limit stop/cable (as hesuggests) The solution in my story is/was a properly welded strutsleeve. Now to my point. I think that although the vee frame/yoke mayprovide greater strength, it also adds additional weight and complexityof fabrication over the striaght cross shock struts which provide morethan adequate strength.Besides I think the straight cross struts look better. :)Steve (As-you-please) e.________________________________________________________________________________

Original Posted By: Gary McArthur[SMTP:garymc(at)admin.hilconet.com]
Yes, bungee failures do happen. Oil from the engine doesn't help andcovers are available to keep the oil off of them. A limit bolt or cableis REQUIRED! If you do go this route, I would suggest not running thebungee struts to the opposite side of the fuselage. This creates a veryflat triangle when the bungee is stretched on a hard landing. Making ayoke so that both sides can be anchored to the yoke on the centerline ofthe fuselage is MUCH stronger. I know this from experience. Was apassenger in a Piet with this type of gear landing in a strongcrosswind. The plane bounced and weathervaned into the wind. The cableused for the throttle was a stranded cable (like a motorcycle throttlecable) but under compression. (We did not build the plane and wereunaware of this item at the time) The cable colapsed when the pilottried to open the throttle. The plane came down slightly tipped to oneside. That side gear stretched the limit bolt enough to pop overcenter. The wheel ended up resting against the wing strut and the proptips plowed the turf. A number of people came out and held up that sideto roll the plane off the runway. Partway back someone pushed on thewheel and it popped back down into it's normal position! We were thenable to put the full weight of the airplane on the gear. Repairsincluded switching to the yoke type gear attachment, replacing thethrottle cable with a solid wire, and prop repairs. It is hard to saywhat might have happened if the gear had held up. The damage couldeasily have been worse. I always suspected that tighter limit stops(allowing less travel) MIGHT have helped the gear problem but the yokeis even better.Was also in this plane when a bungee broke during low speed taxi. Iforget if it was before or after the previous incident (I was just a kidat the time). No problem as the limit bolt kept the prop from hittingthe ground. Some heavy rope around the bungee horns got us home.Another thing people use are die springs instead of bungee cords. Theyare in compression so the stop is not an extra item. And a little oilisn't a problem - just prevents rust. Drag is less too, but probablyisn't a concern in a Piet. :)Jim Skinner________________________________________________________________________________

Original Posted By: Steve Eldredge
Thanks to all those who replied to my inquiry about landing gear. It really helps to hear from those who have been there and done that. Could one of you explain why a taildragger would be more docile with a little toe out. If I am going to the trouble of trying to make the split gear, might as well get the alignment right!Thanks J Mc________________________________________________________________________________