MAC Locator

Find the MAC of any trapezoidal wing quickly and easily. Just take a picture of it and draw the geometric solution right over the picture. Instantly see where 10%, 25% and 33% MAC is located for the wing. Place a ruler over the root cord before taking the picture. You'll have a quick way to verify or check the MAC and CG location, in the field, or in your shop.

Works for any trapezoidal wing in 4 quick steps.
1. Place a ruler or scale, along the root of the left wing (right wing works but left is easier do to the default layout).
2. Take a picture of the wing making sure the root is aligned with edge of the picture.
3. Open this app and select your picture.
4. Drag the dots to draw the mean geometric cord lines.

Short indicator lines at the root show common, initial CG locations for most model airplanes, at 10%, 25%, and 33% back from the leading edge at the MAC. Note that the correct CG will depend on many other factors. This application shows the MAC so you have your starting point. Balancing your model at 10% MAC will typically result in a very stable, trainer type flight handling. This may be too nose heavy for many models but is normal for many tail-less delta aircraft. A CG at 33% MAC is more typical of an agile aerobatic plane that will be close to neutral stability.

Switch for high and low aspect ratio wings with a swipe of the screen.
No buttons to tap.
No numbers to enter.
A visual, graphic solution.

Please note: this app is built with MIT App Inventor. It will request full device access when it installs however this app only requires access to your photo gallery application and nothing else. The only data stored is to track first time use to run the tutorial.