Pietenpol-List: Gear
Posted: Fri Sep 05, 2014 10:57 am
Original Posted By: Scott Knowlton
My 2 cents on the vertical seat base in the photo above marked 3/22/2010:It is a structural mistake to cut it out like that. The plans show this as a 5.5"or 6" tall 23" wide sheet. Yes it has a hole in it for the control tube, butit has a continuous side to side stick at the front of the seat that is cutout in the photo. .If built to plans, even with the hole in it, the 6" plate is a shear web that spreadshalf the seat loads all the way to the sides of the plane. Built in thephoto, weight on the seat will be allowed to bend the bottom of the fuselageat the center line. Don't take my word for this, just ask Jack Phillips aboutthis..Wood structures work because you glue the all together and they become "monolithic."Well made glue joins do a great job spreading loads. deciding to make awood panel removable essentially prevents it from pulling its share of the loadand supporting adjacent panels. Having a seat bottom that isn't glued in isa mistake, and combining it with a structurally cut 6" front support compoundsthe issue..Not flying aerobatics? Go ask anyone with a G meter in their plane where the needlepoints after a really hard landing, and that applies to planes with 9" ofsuspension travel and regular aircraft tires with several inches of sidewalldeflection. Just because it holds a big guy in the workshop means nothing onthe flight line. .If you don't know structures, resist offering guidance to other builders on howto modify load bearing elements of their planes. -ww.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Gear
My 2 cents on the vertical seat base in the photo above marked 3/22/2010:It is a structural mistake to cut it out like that. The plans show this as a 5.5"or 6" tall 23" wide sheet. Yes it has a hole in it for the control tube, butit has a continuous side to side stick at the front of the seat that is cutout in the photo. .If built to plans, even with the hole in it, the 6" plate is a shear web that spreadshalf the seat loads all the way to the sides of the plane. Built in thephoto, weight on the seat will be allowed to bend the bottom of the fuselageat the center line. Don't take my word for this, just ask Jack Phillips aboutthis..Wood structures work because you glue the all together and they become "monolithic."Well made glue joins do a great job spreading loads. deciding to make awood panel removable essentially prevents it from pulling its share of the loadand supporting adjacent panels. Having a seat bottom that isn't glued in isa mistake, and combining it with a structurally cut 6" front support compoundsthe issue..Not flying aerobatics? Go ask anyone with a G meter in their plane where the needlepoints after a really hard landing, and that applies to planes with 9" ofsuspension travel and regular aircraft tires with several inches of sidewalldeflection. Just because it holds a big guy in the workshop means nothing onthe flight line. .If you don't know structures, resist offering guidance to other builders on howto modify load bearing elements of their planes. -ww.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Gear