> Mike Lund wrote: > > FlyBaby > Hi Guys > > Just a quick note to let ya know there is a new lurker here. > > I have been aware of the flybaby for a number of years, but untill > today I had never seen the plans or the plane up close (all my wooden > airplane experience is with Pietenpols). > > Then, I came upon a treasure at about 9:30 this morning... a 1971 > issue of the complete EAA plans for the fly baby. I have had my nose > burried in the book and on every flybaby site I could find all day. > NEAT little plane, and after a Sky Scout and an Aircamper the > construction would be a snap. AND I happen to have an EA-82 handy > without an airframe behind it ;-) hmmmm grey cells are turning ;-) > > Have there been any major changes to the design since '71 (safety > wise) ? Major change has been the addition of a steel strap reinforcing the rear spar carry-through. There was a change page issued for the plans with a batch of corrections on them; the change page is dated April 1970 so your plans set probably includes the change page (page 9-1 in my copy). The information on the spar carry-through mod is summarized on my Fly Baby web page. > Also, being in Southern Ontario, aircraft spruce is hard to get, and > worth more than gold when you get it...has anybody used a different > wood for the plane (with appropriate sizings of course)? FAA Advisory Circular AC 43.13-1B has a chart denoting what woods can be substituted. Jim Pratt has made this document available for downloading at: http://www.moneypit.net/~pratt/ac43/ To summarize the table: Douglas Fir: Stronger than spruce, a bit difficult to work with hand tools. Noble Fir: Slightly exceeds spruce, but 8% deficient in shear. Slightly less hard than spruce. Can be used as a direct substitute, except where shear is critical Western Hemlock: Slightly stronger than spruce, less uniform in texture, but can be used as a direct substitute. White Pine: 85% as strong as spruce, low in hardness and shock-absorbing capability. White Cedar: Stronger than spruce, but gluing difficult. Yellow Poplar: Slightly less strong than spruce Weight comparison: Spruce: 28 lbs/ft^3 Red Pine: 33 lbs/ft^3 Douglas fir: 33 lbs/ft^3 Western Hemlock: 30 lbs/ft^3 White Cedar: 29 lbs/ft^3 Red Fir: 28 lbs/ft^3 Note that the most obvious replacements for spruce, hemlock and fir, are quite a bit heavier (10% and 18%, respectively). However, keep in mind that there are definite standards for quality that should be followed even if something other than spruce is used. AC 43-13 includes some of these standards. Dave Munday referred to the EAA Wood publication; the title is "EAA Building Techniques: Wood." It includes a chapter on evaluating wood. It's available from a fine Experimental Aircraft Association near you.... :-) Ron Wanttaja