Message #52

Date: Nov 16 1999 22:49:17 EST
From: "Mike Lund" <>
Subject: Re: Wood Substitutions

Thanks for the link info Ron. I have a copy of the wood book (I think these
2 are called "building the custom aircraft in wood"), again early 70's
vintage (all these old books came from a donation to the local clubs
library, and as I work unicom at the field I have about unlimeted access)

The ash/ poplar idea came from the old flying and glider manuals and what I
have seen done with aircampers, coupled with knowing the wood market in the
area. (I am one of these guys who dont mind paying a fair price for the
materials, but hate like hell supporting the exchange banks and courier
companies in the process. Last order from AS&S was about $40 US price, and
nearly $150 CDN at my door)

Might be time to join EAA Canada council again (nearest chapter is at
Hamilton, couple hours away) but I always found them nicer people than RAA
-----Original Message-----
From: Ron Wanttaja <>
To: FlyBaby <>
Date: Tuesday, November 16, 1999 10:14 PM
Subject: Re: Wood Substitutions (was New list member)

>> 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
>To summarize the table:
>Douglas Fir:  Stronger than spruce, a bit difficult to work with hand
>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