Conference vmszoo::rc

                    width = 3    inches. length = 36 inches.

 density    1/64    1/32    1/20    1/16    3/32    1/8     3/16    1/4     5/16    3/8     1/2     3/4     1   

     3.0     1.4     2.7     4.2     5.3     8.0    10.6    15.9    21.2    26.5    31.9    42.5    63.7    84.9

     3.5     1.6     3.1     5.0     6.2     9.3    12.4    18.6    24.8    31.0    37.2    49.5    74.3    99.1

     4.0     1.9     3.5     5.7     7.1    10.6    14.2    21.2    28.3    35.4    42.5    56.6    84.9   113.3

     4.5     2.1     4.0     6.4     8.0    11.9    15.9    23.9    31.9    39.8    47.8    63.7    95.6   127.4

     5.0     2.4     4.4     7.1     8.8    13.3    17.7    26.5    35.4    44.2    53.1    70.8   106.2   141.6

     5.5     2.6     4.9     7.8     9.7    14.6    19.5    29.2    38.9    48.7    58.4    77.9   116.8   155.7

     6.0     2.8     5.3     8.5    10.6    15.9    21.2    31.9    42.5    53.1    63.7    84.9   127.4   169.9

     6.5     3.1     5.8     9.2    11.5    17.3    23.0    34.5    46.0    57.5    69.0    92.0   138.0   184.0

     7.0     3.3     6.2     9.9    12.4    18.6    24.8    37.2    49.5    61.9    74.3    99.1   148.6   198.2

     7.5     3.5     6.6    10.6    13.3    19.9    26.5    39.8    53.1    66.4    79.6   106.2   159.3   212.3

     8.0     3.8     7.1    11.3    14.2    21.2    28.3    42.5    56.6    70.8    84.9   113.3   169.9   226.5

     8.5     4.0     7.5    12.0    15.0    22.6    30.1    45.1    60.2    75.2    90.2   120.3   180.5   240.7

     9.0     4.2     8.0    12.7    15.9    23.9    31.9    47.8    63.7    79.6    95.6   127.4   191.1   254.8

     9.5     4.5     8.4    13.4    16.8    25.2    33.6    50.4    67.2    84.1   100.9   134.5   201.7   269.0

    10.0     4.7     8.8    14.2    17.7    26.5    35.4    53.1    70.8    88.5   106.2   141.6   212.3   283.1

    11.0     5.2     9.7    15.6    19.5    29.2    38.9    58.4    77.9    97.3   116.8   155.7   233.6   311.4

    12.0     5.6    10.6    17.0    21.2    31.9    42.5    63.7    84.9   106.2   127.4   169.9   254.8   339.8

    13.0     6.1    11.5    18.4    23.0    34.5    46.0    69.0    92.0   115.0   138.0   184.0   276.0   368.1

    14.0     6.6    12.4    19.8    24.8    37.2    49.5    74.3    99.1   123.9   148.6   198.2   297.3   396.4

    15.0     7.1    13.3    21.2    26.5    39.8    53.1    79.6   106.2   132.7   159.3   212.3   318.5   424.7

    16.0     7.5    14.2    22.7    28.3    42.5    56.6    84.9   113.3   141.6   169.9   226.5   339.8   453.0

    17.0     8.0    15.0    24.1    30.1    45.1    60.2    90.2   120.3   150.4   180.5   240.7   361.0   481.3

    18.0     8.5    15.9    25.5    31.9    47.8    63.7    95.6   127.4   159.3   191.1   254.8   382.2   509.6

    19.0     8.9    16.8    26.9    33.6    50.4    67.2   100.9   134.5   168.1   201.7   269.0   403.5   537.9

    20.0     9.4    17.7    28.3    35.4    53.1    70.8   106.2   141.6   177.0   212.3   283.1   424.7   566.3

    21.0     9.9    18.6    29.7    37.2    55.7    74.3   111.5   148.6   185.8   223.0   297.3   445.9   594.6

    22.0    10.4    19.5    31.1    38.9    58.4    77.9   116.8   155.7   194.6   233.6   311.4   467.2   622.9

    23.0    10.8    20.3    32.6    40.7    61.0    81.4   122.1   162.8   203.5   244.2   325.6   488.4   651.2

  OK, where in the Acton/Maynard/Framingham area(s) is a good place
to buy balsa?  Is it better/cheaper to go to the local hobby store or
order through someone like Balsa U.S.A?  It seems to me that every 
time I go to a hobby shop the quality of the wood is very poor and 
the price is no bargain.

  Jim C

    You could try Fisher R/C in Framingham. I have not bought
    any wood there for a while, but he used to always have a
    pretty fair selection of basla and spruce.
    Wayne

    
    	I concur with John T. about Lone Star Balsa, They have
    excellent wood. One positive thing is that they don't change
    extra to pick out a piece per your requirements.  For the
    average modeler I think that at the least one should make
    up an order for a few pieces of wood and store this wood
    for future use. You'll find that you'll add a piece of tri
    stock here and there on a new kit and have that flexability to
    choose a different piece from what come to you in the kit.
    Ordering ten of this or that at a time keeps the price 
    reasonable yet gives you that needed flexability.
    
    					Tom

        SIG also has good balsa, and you can order the type you want
        (light, hard, C-grain, etc.) for an extra price over vanilla wood.
        
        I still perfer buying wood from a dealer where I can go thru the
        stacks and pick what I want. At the Chicago dealer that has SIG
        wood I usually find better stuff in the ungraded pile than the
        light, C-grain, or whatever. In general, the C-grain is never
        light, the light is never C-grain, but an occasional plain piece
        of wood is light C-grain.
        
        I too go thru all the wood in stock, and buy whatever is good,
        without regard for what I need. I You can never find what you want
        when you need it, so the only alternative is to buy it when you
        find it. I have 2 Sig boxes full of sheets, all top notch stuff.
        Lately the quality of balsa has gone down, so I'm really glad I've
        got a private stash. 

        Someone asked about the scale I use for weighing balsa in the
        store before buying. While at home I have an Ohaus triple beam
        balance at home, that is good to .1 gram or better, it just isn't
        practical to carry this around to hobby shops. 
        
        What I have is the Triner Portable Pocket Scale. It will fit in
        your wallet, and is good for 0-4 oz or 0-80 grams. Accuracy at the
        low end is probably to +/- 1 gram, at the high end it may be only
        +/- 2-3 grams. It is good enough to tell if a piece of wood is any
        good or not, buy (or not buy) it, and take it home for a more
        precise weighing. The scale is a flat piece of metal, kind of
        c-shaped. One end has a pointer that hangs free, the middle has a
        finger loop to hang the scale from, and the other end has a micro
        alligator clip to hold the letter it is designed to weigh. It
        easilly holds balsa of at least 1/4", maybe somewhat thicker. 
        
        The scale is available from Triner Scale and Manufacturing Co.,
        P.O.Box 18643, Memphis, TN 38118. Their number is 800-633-5299.
        They cost only $4.20 postpaid in single quantities. TN residents
        add 7.75% sales tax. Quantity discounts are available, as is
        custom silk screening of the plastic case with your logo. 
        
        Standard disclaimer applies. I have no conection with this company
        other than as a satisfied user of their product. 

    Since I was the one doing the asking, I called them immediately.
    They were very nice about it but they said that since my order
    was under $50 that I must prepay by mail.  I'm going to check
    the local post office first (to see if I can save shipping) before
    I order one.
    
    Glenn

        Get your scale yet? I've been on a buying binge lately, and was
        rather surprised at the accuracy of the pocket scale.Since it
        really can't be read to better than a gram accuracy, and less at
        the high end, I never encountered an error of more than a gram.
        While that's a lot on a 1/32x2x36 sheet, it is really pretty good
        for most stuff; reweighing with the triple beam balance may not
        even be necessary. 
        
        I'm at least curious about other sources. I found ads for Balsa
        USA, (P O Box 164, Marinette WI 54143 800-BALSA US)and will give
        them a try, but wanted to check out Lone Star as well. Can someone
        post info on them? I assume they are in Texas. 
        
        The place in California with the "primo" balsa (by reputation
        only, I've not ordered from them either - yet) is Hobby Woods, P O
        Box 48, Linden, CA 95236 (209)887-3974, but I heard that the owner
        died recently. I don't know what the status of the company is as a
        result. I do know that they custom cut he wood to order, so
        don't expect instant shipment.

        BTW, Aircraft Spruce also sells balsa, but not sheets like we use,
        but as 2" thick boards, 3-4 ft long and averaging 4 ft wide! A
        board-foot (1"x12"x12") is $2.85. 

Re:: Balsa USA
    
    I'm still learning this balsa stuff but I have ordered from Balsa
    USA. I've always been pleased with the quality. I usually order
    with a friend of mine who does know his way around balsa. Balsa
    USA will select out specific weights of balsa for a small charge.
    In fact, on our last order the surcharge was non-exsistent.
    
    Dan Eaton
    

    Re: .10,
    
    Lone Star "_might_" be the outfit Frank Tiano praises so highly.
    If it _is_ the one Frank raves about, it's owned/operated by former
    U-control Combat ace, Riley Wooten.  Frank claims this wood to be
    the clearest-grained, lightest, strongest balsa around and he orders
    about $200.00 worth annually to support his modeling efforts.   

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

        I found an ad for Lone Star in the August 88 MA. They are at 1623
        57th St., Lubbock, TX 79412  (806)745-6394. I spoke with them, and
        beyond the lite 4-6# grade, they will hand select sheets for
        $.15/sheet extra. They have a standing order from one of the 4
        balsa mills in ecuador for ALL of the under 6# wood they can get,
        but lately the crop has been poor, and supplies of contest balsa
        are very limited. It seems that the fast growth is light, but it
        has been (relatively) dry there too, so the wood is running heavy. 

        A couple months back I ordered some wood from Hobby Woods and Lone
        *. Most of it was special request, light 4-6#, C grain stuff. 
        
        Lone Star told me that the light stuff was very hard to get, and
        that they had none at the time. The person I spoke to said that
        they have a standing order with one of the only 4 balsa mills in
        Ecuador for *ALL* of the 4-6# wood that they can get! They took my
        order, with instructions to hold it until the good wood came in.
        It still hasn't, so I'm still waiting, but they haven't billed me
        for it yet either. Since it wasn't a rush, I'm willing to wait as
        long as it takes for the really good wood. I'll post a reply here
        when it does come in. 
        
        I got very prompt shipment from Hobby Woods. Unfortunately, most
        of the thinner stuff they sent wasn't what I had asked for and
        paid for. They charge a 25% premium for 6-8# wood, and a 65%
        premium for 4-6# stuff.  Much of it wasn't C grain at all. The
        thinner sheets were mostly over 6#, with several in the 7-8#
        range. One block that I didn't order light (3x3x12) came in at
        5.5#! The sizing on the thinner wood was quite irregular, with
        some sheets being too thin, others too fat. The surface finish
        wasn't what I'm used to from conventional suppliers either; much
        saw scribing was visible on the surface. Not what you'ld wnat for
        sheeting. I'm somewhat disappointed in their stuff, and intend to
        write them and let them know. 

    I used to know all of this thanks to a GREAT book in my elementary
    school library.  However, my memory is failing me...

    What does A, B, C grain look like and what is each good for?

    Example: C grain has very straight grain lines and is the strongest
    and lightest.  (I think??)

                       _____
                      |     \
                      |      \                          Silent POWER!
      _        ___________    _________   |            Happy Landings!
     | \      |           |  |         |  |
     |--------|-  SANYO  + ]-|  ASTRO  |--|              - Dan Miner
     |_/      |___________|  |_________|  |
                      |       /           |     " The Earth needs more OZONE,
                      |      /                       not Caster Oil!! "    
                      |_____/

        I thought I write this up before - maybe it was in the "old"
        RC.NOTE. 

        The grain of the wood has nothing to do with its weight (density
        really), and little to do with its strength. What you are going to
        do with the wood has a lot to do with what grain you should
        choose. First, the pictures: 

        
        	+-------------------------------+
        	| | | | | | | | | | | | | | | | |	A grain
        	| | | | | | | | | | | | | | | | |
        	+-------------------------------+


               	+-------------------------------+
        	| / / / / / / / / / / / / / / / |	B grain
        	|/ / / / / / / / / / / / / / /  |
        	+-------------------------------+


               	+-------------------------------+
        	|-------------------------------|	C grain 
        	|-------------------------------|
        	+-------------------------------+

        A grain has the straight lines you refer to. Because the grain
        lines run thru the thickness, the wood is very flexible. It is
        good for planking where you need to bend the wood around contours,
        rolling tubes, wing sheeting, and the like. 

        C grain has a very mottled look, as the grain lines are parallel
        to its surface. It is much stiffer, and should be used where
        bending cannot be tolerated. It is prized by HLG builders (like
        me!) for making wings and tail surfaces that resist warping. 
        
        B grain is somewhere inbetween A and C, and is used as general
        purpose wood, such as bulkheads. In a pinch can be used in place
        of either type, with pretty good results. Some folks break things
        down finer, by classifying wood between A and B as AB, and B and C
        as BC.

        Balsa density is a seperate variable. Balsa is the lightest wood,
        but varies ore than any other wood. Ultra Light balsa (I want some
        if you have it!) can be as light as 4 pounds per cubic foot.
        "Contest" balsa is 4-6#. 7# used to be average, but lately 8-9#
        seems more typical. I've seen balsa as heavy as 30#. The density
        is determined by the growing speed, which has to do with the
        weather in the rain forest where balsa grows. In good growing
        years, with lots of rain, the trees grow fast and light. In
        (relatively) dryer years, the trees grow slower, the cells are
        smaller, packed closer together, and thus denser. 
        
        Kits rarely seem to ahve the right kind of balsa for a given
        application. That is why I prefer to buy mine in a store where I
        can examine each piece, and choose the ones that meet my needs for
        each application, or pay the extra cost to get select wood from
        one of the mail-r=order places that will do so for me. I weigh
        them with a small scale, and use a table (see earlier notes) to
        determine their density. Examine the end of the sheet to see the
        grain type. I stockpile wood, and keep a list of my inventory
        online at home. You can't depend on stores having the piece you
        want when you need it. 
        
        BTW, I think the book you mention is by Kauffman, and was about
        building and flying hand launched gliders. The paperback was
        something like $2 and hardcover was $6 back then, but it is now
        out of print. I have a xerox copy, but would pay a good price for
        a copy of this book if anyone has one. 
        
        That's enough for now, let me know if you have more questions
        on this amazing wood.

        Bob

    Bob,

    Thanks a bunch.  That's what I wanted to know.

    However, I still have a few questions.  
    (Yeah, I can hear you now, "Gee, isn't that Miner guy ever happy?"  :-)

    Did I interpret your drawings correctly; they are drawn from the end
    view?  Please elaborate on what the surface of each type looks like. 
    (I saw you said A grain has straight lines.  But, what does
    "mottled" C grain look like?  And, what characterizes B grain?)  

    Is most wood that one sees in the hobby shops (or mail orders or
    comes in kits) B grain or is there actually a good variety?

    Is it true that density has little to do with strength?!?!?  It
    seems to me the 4-6 pound per cubic foot stuff I've bought wasn't as
    strong as medium or heavy balsa.  Maybe that's just a false perception?

    The book I'm thinking of was probably written in the 1960's or maybe
    early 1970's.  It was not dedicated to just HLG's but was basically
    dedicated to all kinds of airplane model building and flying.  It
    included every kind of information you need to build a model from
    A-Z:  tools required (building board, knife, glue (ambroid)),
    typical building methods (stick and tissue (sometimes silk) with
    dope), good building tips (most of which I've forgotten), balsa
    selection (***), proper engine care (internal combustion as well as
    rubber), and anything else relating to model airplanes.  I wish I
    could find a copy of the book again.  Despite some of the dated
    building materials (no CA or MonoKote), it would still be a good
    book to read today.  The pictures in the book were hand drawn -
    almost cartoon style (as my fading memory recalls it anyway).

                       _____
                      |     \
                      |      \                          Silent POWER!
      _        ___________    _________   |            Happy Landings!
     | \      |           |  |         |  |
     |--------|-  SANYO  + ]-|  ASTRO  |--|              - Dan Miner
     |_/      |___________|  |_________|  |
                      |       /           |     " The Earth needs more OZONE,
                      |      /                       not Caster Oil!! "    
                      |_____/

    One other question: What is the proper way to store balsa? 
    How does heat and/or humidity affect balsa? Assuming I find some
    decent balsa (there are several hobby shops that just opened in
    my area, all have brand new , unpicked through stockpiles), how
    long will it "keep". I noticed that several old pieces from my rc
    days 10 years ago still look like brand new!
    
    Doug

        re: .18
        
        Yes, the drawings are sheet end views. As to the "mottled" look of
        C grain, I can't really describe it too well. Go to the store and
        look thru the sheets - you will know it when you see it. B grain
        has a look "somewhere between A and C". 
        
        Kits, stores, mail order, etc. seem pretty random, as it is rare
        for the manufacturer to take the time and expense to grade the
        balsa by grain and density. When they do, they charge a premium
        for their effort. That's why I just go to the store and do it
        myself. 
        
        Yes, denser wood is stronger than lighter wood. Although I haven't
        tested things, I'm not sure that twice as dense is twice as
        strong. My gut feeling tells me there is some diminishing return
        here. Sounds like a good experiment for someont to do. Besides, I
        prefer to use light wood, and then add the strength with carbon
        fiber or the like, giving me both light weight and strong
        structure. 
        
        One thing I forgot to mention in my last reply was that density is
        related to color. The lighter weight wood usually has a much
        lighter (whiteish) color, while the denser stuff is more
        tan/beige. As a result I can glance at a rack of wood, and just
        weigh the 3-5 sheets that are likely good, rather than having to
        weigh every sheet in the rack. 
        
        I don't know the book. If we don't have a "bibliography" note yet,
        we should. 
        
        re: .19 

        The worst way to store balsa is the way they do in most hobby
        shops; standing up on end. Doing so almost guarantees that it will
        warp. I have ordered from SIG enough times that I have a supply of
        their 4x12x36 boxes that are perfect to store balsa in. French
        bread bags are good for grouping various sheets together, and then
        I lay them all down flat in the boxes. These get stored in a
        corner of my workshop, but not sitting on the concrete floor. The
        important thing is that the sheets should all be laying flat. 

        As with any other wood, avoid extreems in heat and humidity. I've
        never had a problem here. I don't know that balsa has a shelf
        life; some of mine is pretty old and still fine. The only way I
        can really tell how old mine is, is by looking at the price I paid
        for it; it has gone up quite a bit over the years. 

    Speaking of price, balsa is "The most expensive lumber in the world".
    
    Glenn

        Just got the Lone * shipment. Another disappointment. I ordered a
        total of 20 pieces, all but 4 being 4-6# C grain. I onlu got 1
        piece of close to C grain in all of that, and the 4-6# wood ranged
        from 5-9#. Not exactly what I waited over 4 months for. 

    I tried copying the BALSA.* from CRVAX1 but recieved and error in
    device type ... Did you rename DISK$RGK ?
    
    Thanks for the info on Balsa...
    
    Don..

	program balsa
C
C	Program (c) Copyright 1981, 1984, 1987, 1988 by:
C
C	Robert G. Kaplow	NAR 11286
C	1628 Waterford Ln.	AMA 14567
C	Palatine, IL 60074
C	(312) 934-1160
C
C	Non-commercial right to use this software is granted to the
C	National Association of Rocketry (NAR), Academy of Model
C	Aeronautics (AMA), and their members and sections, provided
C	that this notice is included in all copies of this software.
C	Any other use of this software requires the permission of
C	the author. 
C
C
C	29-Apr-81	Written - RGK
C	7-Oct-84	Write data to file, cleanup - RGK
C	6-Feb-87	VMS cleanup - RGK
C	27-Apr-87	Indoor and formula added, const adjusted - RGK
C	30-May-88	Long sheets, Metric thickness, standard output format
C
C	Balsa density chart generator
C
C	length * width * thick (in)
C	--------------------------- * 453.6 * density (lb/ft^3) = mass (grams)
C		12^3
C
C	36 * 453.6 / 1728 = 9.45
C
C	Density = grams / ( width * thickness * 9.45 )	for 36" sheets
C						12.6	for 48" sheets
C						4.725	for 18" sheets
C
	implicit complex ( a - z )
C
	real width ( 14 ), thick ( 13 ), mthick ( 13 ), 
	1 ithick ( 15 ), weight ( 13 ), dense
	integer i, j, k
	logical*4 lwidth ( 14 ), lthick ( 13 ), nthick ( 13 ), 
	1 jthick ( 15 )
	data width / .0625, .09375, .125, .1875, .25, .3125, .375,
	1 .5, .75, 1., 2., 3., 4., 6. /
	1 lwidth / 4h1/16, 4h3/32, 3h1/8, 4h3/16, 3h1/4, 4h5/16, 3h3/8,
	1 3h1/2, 3h3/4, 1h1, 1h2, 1h3, 1h4, 1h6 /
C
	1 thick / .016625, .03125, .05, .0625, .09375, .125,
	1 .1875, .25, .3125, .375, .5, .75, 1. /
	1 lthick / 4h1/64, 4h1/32, 4h1/20, 4h1/16, 4h3/32, 3h1/8,
	1 4h3/16, 3h1/4, 4h5/16, 3h3/8, 3h1/2, 3h3/4, 1h1 /
C
	1 mthick / .019685, .0295275, .03937, .059055, .07874, .098425, 
	1 .11811, .15748, .19685, .23622, .27559, .31496, .35433 /
	1 nthick / 4h0.50, 4h0.75, 3h1.0, 3h1.5, 3h2.0, 3h2.5, 
	1 3h3.0, 3h4.0, 3h5.0, 3h6.0, 3h7.0, 3h8.0, 3h9.0 /
C
	1 ithick / .010, .012, .015, .020, .025, .030,
	1 .035, .040, .045, .050, .060, .070, .080, 
	1 .090, .100 /
	1 jthick / 4h.010, 4h.012, 4h.015, 4h.020, 4h.025, 4h.030,
	1 4h.035, 4h.040, 4h.045, 4h.050, 4h.060, 4h.070, 4h.080, 
	1 4h.090, 4h.100 /
C
	open ( unit = 1, name = 'BALSA.DAT', type = 'NEW',
	1 carriagecontrol = 'FORTRAN' )
	write ( 1, 10 )
10	format ( '1   Ye Olde Extended Balsa Charte' //
	1 '    Density in lb./cu. ft.' /
	1 '    Mass in grams.' /
	1 '    Lengths in inches.' / )
C
C	standard 36" long sheets	1/16 to 6" wide
C
	do 70 i = 1, 14
	write ( 1, 20 ) lwidth ( i ), 36, ( lthick ( j ), j = 1, 13 )
20	format ( / 1h1, 20x, 'Width = ', a4, ' Inches.   Length = ',
	1 i2, ' Inches.' // ' Density', 15 ( 4x, a4 ) )
C
	do 40 j = 30, 95, 5
	dense = j / 10.
	do 30 k = 1, 13
30	weight ( k ) = width ( i ) * thick ( k ) * dense * 9.45
40	write ( 1, 50 ) dense, ( weight ( k ), k = 1, 13 )
50	format ( / 16f8.2 )
C
	do 70 j = 100, 230, 10
	dense = j / 10.
	do 60 k = 1, 13
60	weight ( k ) = width ( i ) * thick ( k ) * dense * 9.45
70	write ( 1, 50 ) dense, ( weight ( k ), k = 1, 13 )
C
C	Extra Long (48") table		2 to 6" wide
C
	do 140 i = 11, 14
	write ( 1, 20 ) lwidth ( i ), 48, ( lthick ( j ), j = 2, 11 )
C
	do 140 j = 30, 165, 5
	dense = j / 10.
	do 130 k = 2, 11
130	weight ( k ) = width ( i ) * thick ( k ) * dense * 12.6
140	write ( 1, 50 ) dense, ( weight ( k ), k = 2, 11 )
C
C	Metric table	36" sheets	2 to 6" wide
C
	do 240 i = 11, 14
	write ( 1, 20 ) lwidth ( i ), 36, ( nthick ( j ), j = 1, 13 )
C
	do 240 j = 30, 165, 5
	dense = j / 10.
	do 230 k = 1, 13
230	weight ( k ) = width ( i ) * mthick ( k ) * dense * 9.45
240	write ( 1, 50 ) dense, ( weight ( k ), k = 1, 13 )
C
C	Indoor table	18" sheets	1/2 to 4" wide
C
	do 340 i = 8, 13
	write ( 1, 20 ) lwidth ( i ), 18, ( jthick ( j ), j = 1, 15 )
C
	do 340 j = 30, 80, 2
	dense = j / 10.
	do 330 k = 1, 15
330	weight ( k ) = width ( i ) * ithick ( k ) * dense * 4.725
340	write ( 1, 50 ) dense, ( weight ( k ), k = 1, 15 )
C
	close ( unit = 1 )
	stop 'balsa'
	end

Ollie,
Al has excellent advise about selecting the wood to match the application. I use 
the same procedure. What I do though is I buy my wood in Bundle Deals from Balsa
USA (other mail order places probably have bulk deals also) and then make my
selection. It's a good deal cheaper, you build up your wood stocks, and the
quality of the wood may be better than what you find at the local hobby shop.
After all, what if AL goes thru the wood at the hobby shop before you get there?
8^)  

Whoa there podnah! Before you go off and try Al's method take a listen to this!
To elaborate on what Dan Eaton was saying: Order *BULK* from one of the mail
order suppliers. As an example; for the same price you'd pay to a hobby shop for
2 sheets of 1/16x3x36 you can get 10 from one of the bulk places (I like Balsa
USA). Now, what you get in that bundle of ten will range from soft to hard, and
will also vary somewhat in quality - just like the bin in the hobby shop. How
do you 'spose the hobby shop bought it? 

So,for what you'd pay at the hobby shop for wood to build 1 plane you get enough 
balsa to build several. Your private "balsa cellar" has exactly the same 
characteristics as the stores. To this private collection you now apply Al's 
selection criteria to get the right piece of wood for the application.

I normally advocate purchasing from a local hobby shop, but balsa and CA glues
are two areas where the shops simply cannot compete.

Randy

    
    Does anyone have a current phone number for Hobby Woods??  The number
    posted in 44.? gets me a modem...
    
    So far there are 4 balsa outfits listed...
    
    	BALSA USA
    	SIG
    	Lone Star
    	Hobby Woods
    
    Are there any other balsa suppliers that people would recommend??
    
    What I am looking for (and niether sig nor Balsa USA carry it (although
    balsa USA *used* to.)) is leading edge stock for a flat bottom 
    airfoil.  The stock is *not* symetrical...  It has a flat bottom and
    flat rear surfaces.  It looks kinda like this from the end:
    
    
    
    				    /|	
    			         /   |
    			     /	     |
    			 /	     |
    		      / 	     |
    		    /		     |
     		  /		     |
    	        /		     |
    	      /			     |
    	     (			     |
    	      \			     |
    	       \		     |
    		\--------------------|
    
    
    I had picked up 2 pieces of this at one of the local (NH/MA) stores. 
    I broke one and now I can't find a replacement.  If in your travels to
    other hobby shops you see balsa like this, please let me know!!
    
    thanks,
    jeff
    
    
    

I would just buy 1/4 square spruce and then on top of it mark it at 1/8" and 
then tilt the bed on my dremel scroll saw and start cutting, granted it is not
exactly right but close enough  The finished piece looked like:


          -------
         /      |
        /       |
        |       |
        |_______|

Some guys I know would also cut them on a full size table saw but geezzz...

    Found an ad for another balsa supplier...  I will be calling them later
    today...
    
    	Superior Aircraft Materials
    	12020-G Centralia
    	Hawaiian Gardens, CA 90716
    
    	213-865-3220
    
    	$20 min order, $5 s&h.
    
    jeff
    

        I took Columbus day off to join two friends on an all day drive to
        visit Sig out in Montezuma, Iowa. It was about 5 hours thru
        miserable rain each way from Chicago and worth every minute of thr
        drive.
        
        They gave us a tour of the entire place, which probably took at
        least 2 hours to see it all. We saw everything from the stock of
        kits that they pull yor order from, to folks counting out 12 nuts
        and bagging them, to the printing of new catalogs and plans, die
        cutting of balsa, design shops (Where they were refurbishing one
        of Hazel's full-size homebuilts), decal production and photo shop,
        to the warehouse they store the raw balsa wood. That building must
        have contained 100,000 cubic FEET of raw balsa! The only place we
        couldn't go was the sawmill, due to the hazards. 
        
        As we went from department to department, the people working there
        would stop and explain what happens there. Rather than a single
        tour gide, we were passed from department head to department head,
        each telling us about their piece of the business. We met the lady
        who for the past 15 years has hand stampped that Sig logo on EVERY
        piece of balsa or plywood that you've ever seen! Her son works
        there too. We were welcome to spend as much time anywhere as we
        wanted, to come back later, or to buy anything we saw along the
        way (Visa/MC accepted!) It was amazing to see how much of the work
        is done by hand. I guess that wages are low out there, or they
        wouldn't stay in business. Yet the employees all seem very loyal
        to the company, and eager to talk with their customers. Most were
        elderly women who look like someones grandmother.
        
        We then spent another 2 hours doing wht brought us there in the
        first place: going thru the biggest stack of balsa you've ever
        seen, picking out just the wood we wanted. It was terrible! We
        were rejecting wood that we'd kill to find in a hobby store. Say
        you need 1/32x3x36 for wing sheeting. There is a bin 18x18" full
        of the stuff. Then there are three more bins, graded light, hard,
        and C-grain. After exhausting that, there are another couple bins
        of ungraded wood. Then there are always the 48" sheets, and the
        2", 4", and 6" stuff if you are more flexible. Now move on to the
        1/16th and repeat! Picture your local hobby shop balsa rack. Now
        scale it up so that it is 9 feet tall, and 30 feet wide. Now
        picture 4 of these rows of bins. That is where we spent our time.
        The folks there were more than cooperative in letting us rummage
        thru everything, as long as everything we didn't take got back
        where it came from. 
        
        Anyone planning on travelling anywhere in the area east of Des
        Moines should plan on spending a day visiting Sig. They welcome
        visitors any time they are open for business. You won't regret it.

    Wow!  I just recently put together the cost of the wood for the 
    Eindecker club project...
    
    (The prices that follow are total price/12 kits.  Where possible, 
    balsa is combined to make full sticks/sheets...)
    
    I had a SIG catalog handy and priced it out...  $29.16.  Under the 
    cost of a new kit (if you can find one), but pretty pricey...
    
    A few days later I used the ads in MA...  Superior $19.73, Lone
    Star $18.00!!  I was amazed that these places have balsa for 33% less
    than SIG..
    
    I am undecided which one to use...  Someone recently recommend
    Superior, but they charge $5.00 handling PLUS UPS shipping charges. 
    They also do not take MC/VISA..  Lone Star only charges $4 S&H..
    
    Does anyone have any recent experience with Lone Star??
    
    Thanks,
    jeff
    

    Re: .-1, Jeff, 
    
    I haven't used Lone Star but I fully intend to when I get a bill of
    materials put together for the new 81" MiG-3.  Lone Star is owned/
    operated by Riley Wooten who was one of the top U-control combat fliers
    and designers of the 60's/70's and had many combat models kitted by 
    major mfgr's during his heyday.
    
    His balsa is widely used by top RC scale modelers for scratch building. 
    Frank Tiano and Brian O'Meara are just two names who've used and highly
    recommend Lone Star.  Like I said, I intend to try Lone Star and, based
    on the recommendations I've heard, I feel confident in recommending it
    to others.                    
						 __
				|      |        / |\	   	       
      	         \|/		|______|__(o/--/  | \	   	       
      | |        00	       <|  ~~~  ____ 04 ---- | --------------------
    |_|_|        (O>o		|\)____/___|\_____|_/	   Adios amigos, Al
      |     \__(O_\_	        |	  |___/	 o	   (The Desert Rat)

    
    Hi,
    Can somebody tell me from what country does Balsa come from. Also can
    balsa be grone in-door. What temperature, humidity etc does it need.
    
    Jacques
    

Balsa comes from Equador, in South America.  I'm not sure, but I
think it is only grown in that particular region of the world,
and nowhere else.  It takes about 10 years for a tree to grow to
where it can be harvested for wood.  Actually, last time I read
about it, the model market consumes only about 10 percent or less
of the total harvest -- the wood is used for vibration isolation,
and as packing material.  I believe balsa liferafts have been
obsoleted by foam materials, but I could be wrong.

As to your question about growing balsa indoors...you sly devil
;-)!

I know you don't understand this, but those of us who came of age
in the 60's find it quite funny.

    The **_LARGEST_** consumer of balsa in the world is Japan.  (Why
    doesn't that surprise me?)  They use balsa by the forest-full to line
    the hulls of the super tankers and cargo ships they build and, more
    than any other single reason, that's why the price of balsa has
    skyrocketed over the past 20-years.
    
    According to a thing I read on balsa once, the balsa tree is one of
    nature's phenomena.  In the rain forests of Equador, certain of the
    large trees which form the forest canopy are particularly fragile and
    vulnerable when they are seedlings.  So, when one of these [permanent]
    trees sprouts up, nature magically provides a balsa tree nearby which
    grows at an accelerated rate so as always to be larger than the seedling
    and provide a natural umbrella of protection for it until it becomes
    hardy enough to survive on its own, whereupon, the balsa tree dies and
    makes room for the permanent tree to grow to adulthood.  My memory
    tells me that the 20-year growth period John mentions is not accurate.
    Indeed, I seem to remember that a balsa tree grows to full height in
    something like 5-years then dies.
    
    The accelerated growth rate of the expendable balsa tree accounts for
    it's very open cell structure which lends it its very light weight.  The
    piece I read on the subject mentioned that experiments to grow balsa
    trees in similar (hot-humid) climates in the US and around the world had 
    failed for reasons I've either forgotten or they couldn't explain. 
    Like the giant Saguaro cactus which is unique to Arizona and a small
    section of northern Sonora, the balsa tree is unique to Equador and
    attempts to bypass nature and grow it elsewhere have not succeeded to 
    date.
						 __
				|      |        / |\	   	       
      	         \|/		|______|__(o/--/  | \	   	       
      | |        00	       <|  ~~~  ____ 04 ---- | --------------------
    |_|_|        (O>o		|\)____/___|\_____|_/	   Adios amigos, Al
      |     \__(O_\_	        |	  |___/	 o	   (The Desert Rat)

    From what I've read, Balsa is very heavy when cut.  All that open space
    that makes it so light for model making purposes etc. is filled with
    water!!
    
    The Kon Tiki, a raft that was made to test the ability of Sout American
    natives to make it to Easter Island to test a plausibility theory about
    the source of those big stone heads, was made of fresh balsa.  Dried
    balsa would have filled with water and sank, but apparently the fresh
    stuff had enough resin in it to be a pretty good floater and one which
    was pretty impervious to the hazards of salt water, and stable.  By the
    time the crew made it to Easter Island, apparently the wood was pretty
    full of water anyway and had just barely made it.  The raft was pretty
    close to becoming a submarine.                

Re: Note 44.46 by PNO::CASEYA "THE DESERT RAT (I-RC-AV8) 551-5572" 

>    section of northern Sonora, the balsa tree is unique to Equador and
>    attempts to bypass nature and grow it elsewhere have not succeeded to 
>    date.
						 __
Sorry Al, not quite correct. Balsa is grown successfully in New Guinea. Balsa 
from that area was used to manufacture the Mosquito's built by the GAF in 
Australia in 1940's and early 50's.

John

    Re: .-1, John,
    
    Ain't this conference great...again, I've learned something new.  Was
    balsa artificially grown in New Guinea or does it occur there naturally
    in the rain forests??  BTW, what's the GAF or should it be NGAF or
    RNGAF maybe?  Good ta' hear from ya' again, "stranger!"
						 __
				|      |        / |\	   	       
      	         \|/		|______|__(o/--/  | \	   	       
      | |        00	       <|  ~~~  ____ 04 ---- | --------------------
    |_|_|        (O>o		|\)____/___|\_____|_/	   Adios amigos, Al
      |     \__(O_\_	        |	  |___/	 o	   (The Desert Rat)

Hi Al,

Yes I have been quiet recently, too busy earning money for our employer.

Re: the Balsa trees in PNG (full name is Papua New Guinea), I don't know for
certain but I believe they are native. We get a lot our balsa for modelling from
there some is excellent some terrible. 

GAF is the Government Aircraft Factory. They made a range of wartime aircraft
during WWII like the US not suffering from the hazards of enemy bombing
attacks. The GAF is at Fishermans Bend in Melbourne Victoria, it still exists
but is only a shadow of it's former operation. 

Best of luck with your retirement

John

    
    Anybody knows the mechanical properties of balsa??
    I have a plane design by Pinney, it is completely in pine and flyes
    great. Maby Balsa is not the only wood that could be used for model
    airplanes.
    
    Jacques
    

    
    
    Out of : MATERIALS HANDBOOK by G.S. BRADY & H.R. CLAUSER
    
     Much of the commercial wood is from the tree O. Grandiflora of
    Ecuador. Barrios balsa, O. Concolor, grows from southern Mexico through
    Guatemala and Honduras. Limon balsa is from the tree O. Limonensis of
    Costa Rica and Panama, and Santa Marta balsa is the O. Obtusa of
    Colombia. Red balsa is from the O. Velutina of the Pacific coast of
    Central America. The balsa known in Brazil as Sumauna is from kapok
    tree Ceiba Pentandra.
    
    Jacques
    

    This seems to be a good place to ask this question. I need to know if
    there is any rule of thumb concerning the "Lightening" of ribs and
    formers". 
    
    Things like:
    
    	1. Minimum distance from edge of formers and wing ribs ?
      
        2. When "Lightening" ribs, would it make better sense to lighten
           only the ribs outboard of the ribs supporting landing gear blocks ?
      
        3. What about laminated (Ply/Balsa) inboard ribs ?
    
         
          Don't ever recall seeing anything in this conference about this.
          Just curious for the time being.
          

Rules? Lighten it as much as possible without allowing it to break in use 8^)

One rule I try to follow is to use round holes to lighten. This prevents 
stress cracks from the corners. How much really depends on the strength of 
the part being lightened and the stress it will be under in use. Sometimes 
it's better to leave a part hole but replace it with a thinner but stringier 
piece of wood. The strength is increased while the weight is decreased.
Laminated parts can be stonger too. A piece of 1/64" ply on a rib can greatly 
increase the strength with minimal added weight (so you can use thinner 
laminated parts for the same strength at a weight savings)

Unfortunately, the best way is to try it, break it and try again.

    This modler is in trouble and needs your assistance.  
    
    Does any U.S. manufacturer stock balsa in millimeters sizes?  I have
    purchased the Storch plans from Bob Holman Plans service and all of the
    parts are in millimeters.
    
    I have tried to convert all the milliters sizes into inches but this
    does not seem to work out well at all.
    
    Also, is there a balsa supply house outside the U.S. which has balsa in
    millimeter sizes?
    
    Any help/suggestions are appreciated.
    
    Thanks,
    
    Ollie

If you call National Balsa (413) 796-1925 and don't admit to knowing me, I'm
pretty sure you can get him to cut you the sizes you need. Chances are he'll
select the next larger size and sand it to thickness.

Jim (paying Eric back for some of the "interesting" core orders he's 
     sent my way 8^)

    Jim, thanks for the tip.  I called them this morning and a woman
    answered and was not sure what I was talking about and said they only
    had balsa in inches, not millimeters.
    
    What is the man's name.  I'll talk to him and see if he will be able to
    supply the materials for a kit.
    
    If all else fails, I'll tell him you said to call.
    
    Thanks again,
    
    Ollie

Hi Ollie,

It's Eric Granger. He's busy doing stuff for me today since I got the booth.
He'll be down in the booth with me at the WRAMS show this weekend. I'll be
seeing him tomorrow night, and will ask him then. He's a bit busy this week 8^)

Jim

    Thanks for the information Jim. Twist his arm and tell him he is really
    doing this for you since I am using you as the middle man.
    
    Ollie

No problem, Ollie. Could you give me some example sizes via email tomorrow and
I'll pass them by him.

Jim

P.S. I have a metric wagon. The back door is 43" wide so meter wide European
sheet goods fit but good old 4'x8' sheets don't.

    Jim, thanks for the information.  For you and any others that may come
    across metric sizes balsa, here are the major sizes I am looking for:
    
    Balsa Sticks:
    
    3 x 6 mm
    9 x 16 mm
    6 x 6 mm
    15 x 20 mm
    3 x 3 mm
    
    Balsa Sheets:
    
    12 x 4 or 6 mm
    1.5 x 4 or 6 mm
    
    Ply:
    
    .8 x 6 mm
    6 x 20 mm
    6 x 37 mm
    6 x 12 mm
    
    Spruce:
    
    6 x 9 mm
    
    Is there someone in the U.K. or Europe who knows a supplier?
    
    Thanks,
    
    Ollie
    
    
    

Well, by my rough approximations (I pulled out my calculator and did .6/2.54 =
0.2362") so 6mm is a hair under 1/4". If we go one step further and say that 3mm
= 1/8" then your list starts to look like:

    Balsa Sticks:
    
    3 x 6 mm		1/8"x1/4"
    9 x 16 mm		3/8"x5/8"
    6 x 6 mm		1/4"x1/4"
    15 x 20 mm		5/8"x7/8"
    3 x 3 mm		1/8"x1/8"
    
    Balsa Sheets:
    
    12 x 4 or 6 mm	4mm = 5/32", 6mm = 1/4"
    1.5 x 4 or 6 mm
    
Well, you get the idea. in talking to Eric yesterday about the WRAMS show, I
mentioned it to him and he suggested going to the nearest english size. I can't
picture anywhere that a 0.0138" overage is going to matter much on a piece of
1/4".

Shipping from a UK supplier will probably exceed the cost of the wood.

Jim