RC Model Aircraft Center of Gravity Calculator v2.3 (replaces v1.x)
Note 1: Potentially not compatible with some versions of Android 5.x (Lollipop) yet, please try it out to be sure, I am trying to find a solution. Apologies to those who have updated to Lollipop and find the app behaves strangely.
Note 2: please email if you have a problem or suggestion
Note 3: This app was built with MIT App Inventor, the permissions* (see below) required are the defaults, I have no control over what permissions Google/MIT App Inventor requires an app to have. This app has been published on Google Play since 2012 and since it is still here you can be assured that Google Play has no problems with it.
Note 4: Please see also my RC-E Calculator which includes wing loading, flight time, prop thrust and other calculators:
► RC E Calc Pro
This may prevent your plane from crashing!
This app will calculate the POSITION of the Center of Gravity (CG or CoG or Balance Point) measured back from the leading edge at the wing root.
Enter your measurements for:
- tip chord length,
- root chord length,
- sweep length and
- required CG percentage (eg 25%)
of your model airplane and then the CG, wing area, geometric mean chord and tip-to-root chord ratio will be calculated automatically, no tapping required.
You can use inches or centimeters and the result will be in the units you used (don't mix units though).
A too rearward CG position can cause unrecoverable (potentially fatal) instability!
25-30% recommended for most conventional wings, 12-18% for flying wings, 15-19% for Delta wings.
Thanks for downloading and comments welcome.
(*This app requires the following default App Inventor permissions:
android.permission.INTERNET - to check for updates and so that the screen's background image property can be set to the URL of an image on the web if there is a background image
android.permission.WRITE_EXTERNAL_STORAGE - to move the app to EXT SD on your phone if necessary.
android.permission.READ_PHONE_STATE - to check for incoming phone calls and then hide the app if necessary.
android.permission.READ_EXTERNAL_STORAGE - access the app on EXT SD if necessary.)
Version 2.0+: implemented due to Google licensing changes.
- No longer requires a button tap to calculate, calculates automatically after the all the fields are filled.
- Added wing Area calculation
- Changed layout for ease of use/visibility
- Fixed small bugs
- Resize & refit for tablets
- Refit text flow for large numbers
- Center everything
- Minor layout improvement & bug fixes
- improved layout
- improved images
- new instruction page
- corrected wording