MAC calculations for tapered wing?

[pqt_bach]

Hi there,

I was working out the CG on a new plane (no instruction manual) anbd I have a little question:

The plane has a tapered wing (like an Extra 300) but all MAC equations and calculators refer to rectangle wings or full swept back wings - so what category does this type of wing belong to?

Thanks,
Dan

[JetPlaneFlyer]

This one does tapered wings (as do all the others I've come accross?) http://adamone.rchomepage.com/cg_calc.htm

Steve

[MCarlton]

http://www.airfieldmodels.com/information_source/math_and_science_of_model_aircraft/formulas/mean_aerodynamic_chord.htm

It doesn't matter if the wing is swept or straight, the same calculations apply. The only difference is if the wing is elliptical.

[pqt_bach]

So if the leading edge is swept back and trailing edge is swept forward, I still use the same calculations as I would use with a fully swept wing?

Cheers,
Dan

[JetPlaneFlyer]

So if the leading edge is swept back and trailing edge is swept forward, I still use the same calculations as I would use with a fully swept wing?

Cheers,
Dan

Correct,

But if you want to calculate the CG working out MAC of the wing is only part of the story... You also need to take into account tail area and tail moment arm; which is where the CG calculator i linked to comes in.

Steve

[pqt_bach]

Thanks :)

The calc takes all of this into account and even the weight distribution of the landing gear and the like... nice...

Well, thanks for the quick lesson, guys

Cheers,
Dan

[CloudyIFR]

Adam One's software is very nice, convenient, accurate and easy to use.

The only limitation I see is that it'll only do up to a two panel wing.

If you ever have a plane with more than two panels mine will do up to four, but it requires MS Excel, OpenOffice etc. spreadsheet program.

It's available at my website.

Curtis
www.TailwindGliders.com

[nmasters]

Here's a little program that finds MAC on a 5 panel wing: http://pagesperso-orange.fr/scherrer/matthieu/english/mce.html

[CloudyIFR]

That's an excellent one too Norm, however, it only calculates the MAC and NOT the balance point as stated in post #5, but you know that and a whole lot more! :)

Curtis

[nmasters]

The box labeled <Center position> marks a line on MAC a given % from the LE of MAC. Granted you have to know that % but if you can provide that number the program returns the distance from the nose. Limited but useful.

--Norm