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  1. #1

    Smile

    Just completed my second TBH; built along the same style as my first one (the one in my Yahoo profile photos). I’ll post some photos there in the next few weeks. The main change I made was to the internal depth of the hive in order to limit the size of the comb.

    The top bars are still 19-inches long - Langstroth compatible - useable comb building length is about 18 inches. The bottom width is 9-1/2 inches wide and the depth from the bottom side of the top bars to the bottom board is 10 inches (or about 11 inches with the bb removed and the screen being used). Internal length of the hive is 44 inches and will include a 3/4-inch thick follower board. This will hold 30 top bars (equivalent to three deep brood boxes) and if my calculations are correct should be a volume of about 3-1/2 cubic feet or 99 liters.

    Hopefully, this hive size will maximize the available comb area, yet not result in comb failure in our Texas heat. I am planning on initially sitting it up, using the solid bottom board in place. Perhaps after the brood comb "ages", I will remove the bottom board and go with just the screened bottom.

  2. #2
    Join Date
    Jan 2004
    Location
    Porter, Ok USA
    Posts
    491

    Post

    Texbeeguy:

    I only today completed a TBH on the Crowder design. This is based on 1x10 stock, cut at 30 degrees off the vertical. The design uses a l9 inch top bar and a 7 inch depth, just more than a medium super. I cut the planks 39 inches long and using 2x end pieces wound up with 25 inch and 3/8ths bars.

    Splines on the bars project about 3/l6ths down and I left ends about 4 inches high to hold a shade top off the bars.

    There are enough of us now that by summer's end we should have some idea how the various designs work. I can easily imagine having to harvest several times from the Crowder hive as it has less capacity than any discussed here so far. I cut a division board of half inch plywood and dadoed a top bar to take it.

  3. #3
    I haven't applied any 'trig' to my dimensions but I did do a quick angular measurement as I was building it and believe I recall the angle came out at about 25 or 26 degrees off the verticle.

  4. #4
    Join Date
    Aug 2002
    Location
    Nehawka, Nebraska USA
    Posts
    46,336

    Post

    Well I went for small comb and steep angle. Mine is 22 1/2 degrees off of vertical. The bottom of the comb should be about 4" wide, the top about 12" wide and the depth of the comb is about 8" deep. That's allowing a 3/4" space at the bottom and a 3/8" space on the sides. The bars are 15". It's made of 1 by 12 sides and a 1 by 6 bottom.

    I'm tired of combs breaking off. I was also hoping to get three 4" by 4" cut combs from each bar.


  5. #5
    Join Date
    Feb 2003
    Location
    Near Ocean City, MD
    Posts
    14

    Question

    hi guys,
    i found a couple of cool sites to do conversions/calculations for volume of a trapezoid, converting cubic inches to liters or cubic feet, etc., as I am trying TBH's as well and just wanted to understand the volume as compared to a Lang hive.

    I am no mathemetician (hence my finding/trying to use these sites, lol), but it was interesting to punch in the numbers that txbeeguy gave for his hive measurements: it was much smaller than 99 liters; it ended up being 2873.75 Cubic Inches which converts to 1.66304 Cubic Feet or 47.10076 Liters (I tried to use the largest measurements, i.e., 19" top bars---yes I know 18 is usable width, but thought I'd put in the whole length after the initial measurement was even smaller than 47 liters---also used 11" depth, 44" length, 9.5" bottom width).

    I was reading an article by Marty Hardison discussing hive volumes:
    http://www.gsu.edu/~biojdsx/mh2.htm#locale

    In that article he wrote that a Lang deep was about 40 liters (I got about 42 liters doing inside measurements, but what the heck do I know ); and that the KTBH as as normally used in Africa had a volume of anywhere from 40 to 120 liters. He talks of settling on a hive with a volume of 76 liters; assuming this is the hive he gives some measurements and links for in the article (top 16", bottom 10", height 10", length 40"), I tried punching those measurements in and came up short as well (actually, to get the volume he stated, the length would have to be 80" instead of 40" according to the way I was filling in dimensions on the trapezoid tank volume site I was using); I am confused, of course, and want to know if anyone can tell me where the measurements are wrong. If you look at the trapezoid tank volume site, the only thing I wasn't sure about was the "partial height" measurement--being ignorant of such mathematical calculations, I am simply assuming that the partial height is 1/2 the total height (i.e., 6" if total height is 12", etc.). Since the volume of any of these calculations I am getting are much smaller than either txbeeguy or Marty Hardison are getting, I just want to know the proper way to calculate the volume, as I am obviously doing something wrong, I think, and I would rather not stumble around in the dark if someone can flip the light switch for me .

    Here are the links for the two sites I used (at the bottom of the trapezoid tank volume site, check out the 'select another shape' link about 2/3 of the way down the page; it gives volume calculator pages for a bunch of different shapes--boxes, milk cans, etc. pretty cool to look at, I thought, especially to one mathematically challenged as myself, lol !)
    Also, on the conversion charts page, I used the very bottom calculator, there are 3 on the page, but if you look at the bottom one you can punch in cubic inches/feet, etc. and get any number of measurements to include liters-- the other calculators give a lot of other measurement conversions as well)

    Trapezoid Tank Volume Calculator: http://grapevine.abe.msstate.edu/~ft...trapezoid.html

    Conversion charts page: http://dropbears.com/u/utilities/convert3.htm#volume

    I appreciate any clarification on whether I am just being retarded or if the 'partial measurement' is specific as to what percentage of the total height it should be to properly figure it out, because I can't get any numbers to match up.

    Thanks a bunch,
    Robert

  6. #6
    Join Date
    Aug 2002
    Location
    Nehawka, Nebraska USA
    Posts
    46,336

    Post

    I don't know what the typical method is but here's mine.

    If you have a top bar hive that is 12" across the top inside and 10" across the bottom inside and 9" high how much area does the end take up (we'll get to volume in a minute). Well if you were to take a sqaure and mare a line verically where it intersects the side in the middle you would have a triangle at the top that is 1" wide at the top and if you cut that triangle off it fits exacly in the space at the bottom to make the side perpendicular. If you do that on the other side you now have a square that is exactly 11" wide by 9" deep. So in other words (don't cut your hive it was just making the point) if you take the width at the top plus the width at the bottom and divide it by 2 and consider that one diminsion of a sqaure and multiply it by the depth you have the area of the end. Just take that times the length and you have the volume.

    Since we are doing inside measurements my hive has a 15" top bar, but the inside is only 13" at the top and 4" wide inside at the bottom. So that is 17" divided by 2 is 8 1/2" inches. The depth is 9" so that is 8.5 * 9 = 76.5 square inches. The length (inside) is 47.25" * 76.5 = 3615 cubic inches. Of course you could have done all the measurements in metric and saved converting. But the conversion is simple enough. one cubic inch is 0.016387064 liters so you could multiply it by that. But there is a nice conversion site http://www.admiralmetals.com/metric_conv.htm and they say it's 59 liters.

  7. #7

    Exclamation

    Michael,
    IF you have comb failure problems with that TBH, we're ALL in trouble!

  8. #8

    Post

    The math is pretty simple:

    Volume of a rectangular prism = length x width x height

    Volume of a triangular prism = 1/2 length x width x height
    --
    Using the first formula,
    44 inches x 18 inches x 10 inches = 7920 cubic inches
    --
    Using the second formula, twice (once for each small triangular prism that was “over estimated” via using a rectangular shape in the first equation):
    First:
    (18 inches) – (9-1/2 inches) = 8.5 inches
    (8.5 inches) / 2 = 4.25 inches (per each side, left and right)

    Now the second formula,
    “Over estimated” volume from the use of the first formula:

    (1/2 length)
    (.5) x 44 inches x 4.25 inches width x 10 inch height = 935 cubic inches

    935 cubic inches x 2 (one for left side & one for right side) = 1,870 cubic inches that need to be subtracted from the original calculation:

    7,920 cubic inches – 1,870 cubic inches = 6,050 total cubic inches of hive volume.
    --
    One cubic inch = 0.0005787 cubic feet, thus
    (6,050 cu in) x (0.0005787) = 3.5 cubic feet of hive space

    or

    One cubic foot = 28.3168 liters, thus
    (3.5 cu ft) x (28.3168) = 99 liters
    --

    Of course, that's the maximum volume of the hive. Obviously, the "follower board" allows for adjust of the hive volume (which is it's purpose). For instance, the bees may be overwhelmed by having to pull out 30 top bars of comb, so I start them off with half that amount and allow them to expand into the remaining 15 top bars at their own pace (to include the following year, if necessary).

  9. #9
    Join Date
    Jan 2004
    Location
    Porter, Ok USA
    Posts
    491

    Post

    Two comments:

    The conversion is all straight math except determination of the square area of the ends.

    That determination is simply cutting the ends into squares as pointed out above. A vertical line from the tip of the triangle to the point where that intersects the top line creates a right triangle. On a right triangle, the short side is always one half of the hypotenuse--you can figure your measurements pretty easily.

    Second Point: The crowder hive based on one x ten material is low volume but only 7 inches deep. Should not be a major comb collapse problem there.

    If you want 4 x 4 combs, you should easily cut them out of the crowder design. I've not measured, but you might get 4 of them.
    Ox

  10. #10

    Exclamation

    Robert,
    It's why you can't always trust what you run across on the internet. While I don't have time to "troubleshoot" their trapezoid webpage, even a quick "sensibility" check of their own site shows this calculation is off. For instance, go their main page for volume calculations: http://grapevine.abe.msstate.edu/~fto/tools/vol/
    and run the numbers for just a simple rectangular prism, using their "box" calculator page and just for grins, use my same dimensions except cut the width by half (which certainly would represent a much smaller volume than what we're checking) and you'll see it it yields a larger number than the 2873 number you first mentioned. This is just a quick check you can do without knowing any math and yet serves as proof their trapezoid volume calculation is off.

  11. #11
    Join Date
    Aug 2002
    Location
    Nehawka, Nebraska USA
    Posts
    46,336

    Post

    I went to the grapevine site http://grapevine.abe.msstate.edu/~ft...trapezoid.html and I put in my numbers (the total height as the partial height) and the results were matched my calculations exactly. Mine is b1=4 b2=13 h=9 h1=9 l=47.25 and results in a volume of 3614.625 which I had rounded up to 3615.

    Looks correct to me. But I think the "partial height" is confusing. Maybe that is how full it is?

    [This message has been edited by Michael Bush (edited March 03, 2004).]

  12. #12
    Join Date
    Aug 2002
    Location
    Nehawka, Nebraska USA
    Posts
    46,336

    Post

    TxBeeGuy's hive on the grapevine site with b1=9.5 b2=17.5 (subtracted for the walls) h1=10 h=10 L=44. It says the volume is 5940 cu inches which converts to 97.3 liters.

  13. #13
    Join Date
    Jan 2004
    Location
    Porter, Ok USA
    Posts
    491

    Post

    The conversation got me to thinking, so I went out and carefully measured the Crowder hive, using the division board as the end measure. It's a perfect fit, so that part is accurate. Nine inches on bottom, l7 across the top. Seven inches deep.

    That works out to a rectangle 7 inches by l3 inches. (take the triangular piece, 4 inches on the short side x 7 inches deep, match it to its mate on the other side to get a 4 x 7 piece added to a 9 x 7)

    The hive is 36 inches long (nominal) so that 7 x 13 x 36 gives volume in sq in.
    2.54 cm per inch, cubed, gives 16.387 cc per cu in, x 3276 cu inches--53,683.8 cc or 53.7 litres.

    Since we will all make our Crowder hives a bit longer or shorter than the next fellow, all that is useful is the end measurements. If built from 1 x 10 stock and cut to get the maximum use of each board the area should be
    91 square inches or very close to that.

    seems that I recall that the volume of the hive built to hardison's dimensions and again built three feet long was around 70 litres.

    I built division boards to restrict initial volume for both Crowder and Hardison prototypes here. I will obviously have to have one for the straight sided Kenya hive.

    I am looking forward to late Summer and Fall to see how these various designs work out.
    Ox

  14. #14
    Join Date
    Oct 2001
    Location
    Bradenton, FL, and Davenport, IA, USA
    Posts
    930

    Post

    Actually in the case of prisms and equilateral trapazoids, the measuring is simply two rectangles.

    The center rectangle with the triangles cut off, and the single rectangle you get when you match the two "cut-off" triangles. No need to do triangle math or trig.

    ,-----,
    |..../|
    |.../.|
    |../..|
    |./...|
    |/....|
    '-----'

    Like so.

    Then again, figuring out the area of a triangle is easy. Figure it out for a rectangle and divide by two. Also demonstrated above.

    [This message has been edited by Scot Mc Pherson (edited March 03, 2004).]

    [This message has been edited by Scot Mc Pherson (edited March 03, 2004).]

  15. #15

    Big Grin

    The trig I mentioned was for calculating the ANGLE of the sides (off verticle) from just the linear measurement of the hive (the triangle). But as I've said, I haven't done this; I just took a rough angular measurement during construction.

  16. #16

    Post

    > the "partial height" is confusing. Maybe that is how full it is?

    {to myself} duh.... of course, that's it!
    Obviously I was asleep at the wheel...
    too many work hours this week!


  17. #17
    Join Date
    Feb 2003
    Location
    Near Ocean City, MD
    Posts
    14

    Post

    Michael,

    --Looks correct to me. But I think the "partial height" is confusing. Maybe that is how full it is?

    --Makes sense now that someone pointed that out to me!!!! lol

    I was just assuming that the trapezoid was taken to be full, and figured the "partial height" had a more esoteric 'fudge factor' reason for being needed; thank goodness that's over with. If these numbers are coming out correctly now, this seems to be an easy site for people to figure out how big their TBH's are, and how they compare volume-wise to others.

    Thanks for helping out with the answer, Mike.

    Robert

  18. #18
    Join Date
    Nov 2003
    Location
    McMinnville, TN, USA
    Posts
    716

    Post

    If you look at the trapezoid tank volume site, the only thing I wasn't sure about was the "partial height" measurement--being ignorant of such mathematical calculations, I am simply assuming that the partial height is 1/2 the total height (i.e., 6" if total height is 12", etc.).

    Partial hieght tells the computer the angle. It is the true height of the box. Anyone got a box completed care to measure and punch the numbers in with this being set right?

    I was going to draw a line as you have mentioned to "cut" the triangles off to get my measurement.

  19. #19
    Photos posted:
    http://photos.yahoo.com/bc/txbeeguy

    Not painted yet but otherwise ready to go.
    Internal dimensions as given in the first posting of this thread.

  20. #20
    Join Date
    Jan 2004
    Location
    Boynton Beach, Florida, USA
    Posts
    278

    Post

    Nice! This year will be a great year for testing the practical depth for a tbh.

    Regards
    topbarguy

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