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Building Tips and technical articles. => Building techniques => Topic started by: Perry Rose on April 27, 2023, 04:36:51 PM
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For some reason I was wondering how much of an increase there would be in wing area by adding a couple inches to the span of a Twister wing. Using 50.5 span instead of the 48 and using the same flaps as shown on the plans. I figure the wing area would be 491 square inches. The plans say 490 in stock form. I measured the plans and did the math and came up with 470 square inches. That is a head scratcher. The only thing I can come up with is that the prototype was 50 inch span and the plans were changed with the exception of the wing area.
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For some reason I was wondering how much of an increase there would be in wing area by adding a couple inches to the span of a Twister wing. Using 50.5 span instead of the 48 and using the same flaps as shown on the plans. I figure the wing area would be 491 square inches. The plans say 490 in stock form. I measured the plans and did the math and came up with 470 square inches. That is a head scratcher. The only thing I can come up with is that the prototype was 50 inch span and the plans were changed with the exception of the wing area.
It doesn't answer your question but I added one rib 4" to mine (1 rib one each side) and it flew really great. Never did the area math. Did all of the other "Fancher" mods too.
Ken
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Perry,
It looks to me like the plans I have are the same--and I would guess that the copying process had a minor scaling issue. Mine measure out to about 47-5/8" which would equate to less than a 1% scaling error when compared to the claimed wingspan of 48".
If I run the numbers using the claimed wingspan of 48", I get 472.5 sq. in. Still not quite the claimed 490 sq. in. on both the box and the plans.
There's a story somewhere--and it looks like it is in the original math....
On the Twister I built I added extended, shaped-block tips which added about 3" span per side. They look nice, but I should have done more lightening (thinning) work.
Dave
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YEA .
The PAPER can expand / contract maybe 3/4 inch to a A1 sheet , from humid cool to schorching dry . so like horsepower , needs a Std. barometer Correction . S?P
(https://outerzone.co.uk/images/_thumbs/plans/8708.jpg)
Eres Mr Fanchers contribution .
Four Ninty and Fourty eight , are almost the same , bar a decimal place or two .So an inch is ten . More or Less . So four inches is fourty , twice is eighty . But if its eight its thirty two . Twice .
Ahem , if the CHORD of the ribbed bits EIGHT , ya getta bout 30 a side , so a extra 60 or 65 or so . thereabouts . Which is about 10 % more area . or , at the same weight , 10 % less loading .
Or can Go Harder , before you load it up to the Std. limit . VD~