lml@lancaironline.net Mailing List Archive

<<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> I want to thank everyone that replied to my back-pain post. I have reviewed all the data and discussed the problem with my doctor (showed him a copy of the fuselage profile, blueprint G) with pilot in seated position. The flap push rod cover panels were penciled in. I have arrived at the following conclusions. 1. The contour of the seat back is the most important factor in regards to middle back pain. 2. Whether, or not you use temperfoam, conforfoam, other foam or no foam on the seat back has no bearing on the problem if it is of uniform thickness. I have had a 2 layer conforfoam seat back since day one. 3. The depression angle formed by the flap push rod cover and the upper seat back is a major contributor to the problem. This contour forces your spinal column in to a un-natural position. 4. The pelvis (top) needs to be rotated to a more forward position. This is equivalent to saying that the seat back must support the lumbar vertebrae. I have made two changes to my seat back. First, the 2 layer conforfoam back cushion has been modified to taper down to 1 layer at the very bottom. The taper starts at the vertical position of the flap push rod cover and seat back junction. Second, as a temporary experiment, I have added a piece of 1 inch Styrofoam, tapered down to zero thickness at the top and bottom. The 1 inch thickness is only at the top of the flap push rod cover. The Styrofoam panel is positioned behind the back cushion. I have not yet taken a long trip with the modified seat back so, I don't know the result at this point. As they say "the proof is in the pudding". I will post the results after my next trip. Incidentally, I do believe the story about the guy who only had a middle back pain only when he carried his billfold in his back pocket. A bulge behind the lower part of the pelvis would only aggravate the situation. Maybe, that's why I only had the pain in the left side of the back. I carry my billfold in the left back pocket. Bob Jude LML website: http://members.olsusa.com/mkaye/maillist.html LML Builders' Bookstore: http://www.buildersbooks.com/lancair Please remember that purchases from the Builders' Bookstore assist with the management of the LML. Please send your photos and drawings to marvkaye@olsusa.com.