RE: Pietenpol-List: Another sketch
Posted: Thu Sep 03, 2009 8:19 pm
Original Posted By: "Bill Church"
The method-I use to determine whether the gusset is the right size is the following:I measure my gusset, then I compare my measurement to the size shown in the plans. If they match, we're good to go.I know, this sounds like a joke, but it really isn't.The plans call for the fuselage gussets to be 1/8" x 2 1/4" and cut in lengths to fit. So the correct size of the gussets for this plane will be 2 1/4" wide, and just long enough to cover the diagonals and uprights. Making the gussets longer than that will-add weight, and use more plywood, but will provide very little additional strength. Making the gussets shorter-could result in a considerably weaker joint.The size of a required gusset could be determined by taking into account the forces expected to be acting upon the joint, coupled with the strength of the various materials, and the strength of the adhesive. Then, the bond area (the contact between frame and gusset) could be calculated, and from that the configuration of the gusset could be established.I'm sure that IF someone with the proper technical background was so inclined,-and performed a detailed structural analysis of the fuselage structure, they would probably find that the 2 1/4" dimension might be a bit of "overkill" in certain areas. Maybe in certain locations-the gussets-would only need to be 2", or 1 7/8" or whatever. Sounds like a lot of work with very little benefit. If we keep in mind that this aircraft was designed by a man with no formal education in aircraft design, and was designed 80 years ago, to be built by an average person with no special skills or equipment, it becomes easy to see why the gussets are all the same width. It keeps-things simple. Simple-is good. Set the fence of the table saw at 2 1/4", and run a sheet of plywood through, to produce strips which can be easily trimmed to length-to suit each location.One thing we do know for sure is, that when built to the plans, the thing works.-Bill C.----________________________________________________________________________________Subject: RE: Pietenpol-List: Another sketchDate: Fri, 4 Sep 2009 14:08:37 -0400
The method-I use to determine whether the gusset is the right size is the following:I measure my gusset, then I compare my measurement to the size shown in the plans. If they match, we're good to go.I know, this sounds like a joke, but it really isn't.The plans call for the fuselage gussets to be 1/8" x 2 1/4" and cut in lengths to fit. So the correct size of the gussets for this plane will be 2 1/4" wide, and just long enough to cover the diagonals and uprights. Making the gussets longer than that will-add weight, and use more plywood, but will provide very little additional strength. Making the gussets shorter-could result in a considerably weaker joint.The size of a required gusset could be determined by taking into account the forces expected to be acting upon the joint, coupled with the strength of the various materials, and the strength of the adhesive. Then, the bond area (the contact between frame and gusset) could be calculated, and from that the configuration of the gusset could be established.I'm sure that IF someone with the proper technical background was so inclined,-and performed a detailed structural analysis of the fuselage structure, they would probably find that the 2 1/4" dimension might be a bit of "overkill" in certain areas. Maybe in certain locations-the gussets-would only need to be 2", or 1 7/8" or whatever. Sounds like a lot of work with very little benefit. If we keep in mind that this aircraft was designed by a man with no formal education in aircraft design, and was designed 80 years ago, to be built by an average person with no special skills or equipment, it becomes easy to see why the gussets are all the same width. It keeps-things simple. Simple-is good. Set the fence of the table saw at 2 1/4", and run a sheet of plywood through, to produce strips which can be easily trimmed to length-to suit each location.One thing we do know for sure is, that when built to the plans, the thing works.-Bill C.----________________________________________________________________________________Subject: RE: Pietenpol-List: Another sketchDate: Fri, 4 Sep 2009 14:08:37 -0400