I want to blow up the plans of a 71" long, 824 square inch wing by 25%. Does this mean then that to figure out the wing area of my new larger 88.75"sized wing I simply multiply 824 Sq. inch x .25 = 206 sq. inch, 824 + 206= 1030 sq. inches???

The dilemma and suspicion I have about this math, is that when I've seen every company (like Top Flite for example) increase their 63" wingspan P-47 or F4U model to a giant 85" wingspan version of the same model, the wing almost doubles in wing area instead of proportionatly increasing 25% -30%!! Blowing up my plane 25%using these Top Flite models as an example, would likely turn my plane with a wing of 824 sq. inches, closer to a wing area of 1300 or 1500 sq inches. ( instead of the 1030sq inches I come up with mathematically.)

So then the question is: What would a 71" wing presently at 824 square inches, work out to in square inches if I increase the length 25% to 88.75"long. Evidently the math formula may not be as simple as I expected.

You will need to muliply your area by 1.25^2, since both chord and span are increasing and area is chord * span. So, multiply your area by 1.5625.

Hi,

"I want to blow up the plans of a 71" long, 824 square inch wing by 25%. Does this mean then that to figure out the wing area of my new larger 88.75"sized wing I simply multiply 824 Sq. inch x .25 = 206 sq. inch, 824 + 206= 1030 sq. inches??? "

I suggest enlarging the plans vs blowing them up

Wing area is span times cord. I assume you are going to increase the cord by 25% so here is the math.

71" *11.6" = 824 sq "

88.75" * 14.5" = 1286 sq"

Hope this helps,
Dave

I agree...
Blowing up your plans can start a fire, whereas enlarging them simply makes them bigger.

Sometimes though, after making a plane from plans, I've considered blowing up the plane.

I fill dumb, what is the difference between blowing up and enlarging. I use either word when I am making something larger then the original. Please enlighten me, as I want to blow up/enlarge my Sig SE plans to make a 80" one.

Main Entry: blow up
Date: 1536
transitive senses
1 : to build up or tout to an unreasonable extent <advertisers blowing up their products>
2 : to rend apart, shatter, or destroy by explosion
3 : to fill up with a gas (as air) <blow up a balloon>
4 : to make a photographic enlargement of
5 : to bring into existence by blowing of wind <it may blow up a storm>

Those guys are just being funny

Oh yeah, Dave nailed it on the head.
Cheers.
James

toyking23,

We're just kidding around a bit here. Both phrases are fine.

Quoting Hannibal Lecter:
"Oh Clarice, you really must get more fun out of life."

Have fun!

Wells and Dave,

Thanks for the help. It was a relief to crunch the numbers properly to come up with a plane at something like 32.5 oz. per square foot wing loading, instead of the 40.5 oz. I was getting using my own "math made easy" method.

As for you other guys; I'm glad I didn't ask you how to "multiply" something. I'd be getting a two day course in sex education.

-Randall
OK, a little silly humor never hurt anybody

Try this one for obtaining a desired wing area.

824 known area / desired area 1286

1286 divided by 824 provides a ratio = 1.56

square 1.56 and you have a ratio that can be used on a copy machine of 125% which will net you 1286 sq.ins. @ 88.75 wing span.

Similar math while looking for a specific wing area!

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An 80" SIG SE would be figured like so:

desired WS = 80" divided by known WS 51.5' = 1.554
known Wing Area = 614sq.ins.
614 divided by 51.5 = 11.92 chord
11.92 x 1.554 = 18.5 chord
80 x 18.5 = 1480sq.ins.

Use a ratio of 1.55% on the copy machine.