CG Finder PLUS v1.3
CG Finder PLUS v1.3
Available NOW - $1.99!
WHAT IS DOES:
Gives you an easier way to find and adjust the center of gravity of your airplane. You can also use this app to find the CG of other objects too! (See bottom of page)
WHAT MAKES IT DIFFERENT:
CG Finder is unique in that it displays your center of gravity in a new way. In real time, you are able to pick a station in your aircraft and increase/decrease its weight in a few ways:
Enter Weight Directly With Keyboard
Nudge Weight +/- One Pound With A Button
Increase/Decrease Weight From 0-500 Lbs. With A Slider
WHAT TO LOOK FOR:
Green & blue are good, red is a warning. The important values will either be green/blue or red in color. Green/blue text and sliding pointer rings mean your center of gravity is within the limits your entered for your aircraft and that your gross weight has not exceeded the maximum weight you entered.
IMPORTANT-These numbers displayed in CG Finder are for reference purposes only! It is up to you to verify the numbers given here with your own calculations as part of your usual pre-flight check.
Data is stored each time you make a change. Each time you launch the app it will continue where you left off.
1. DISCLAIMER:
After launching the app you must agree to this disclaimer by pressing the "I Accept" button. Here you can also view the help information and choose your preference of US or Metric values.
2. ENTER VALUES:
One this page you will be entering values for your aircraft. Start by entering the maximum allowed weight (Max Weight) for your aircraft. Next enter the maximum allowed forward and aft center of gravity (Forward CG & Aft CG). In order to run a basic W&B check, you will also be entering ARM and Weight values for your Airplane, Pilot & Fuel.
Additional stations have been added since the original CG Finder App. Stations 4-11 can be custom named for the specific points in your plane.
Press the "Continue-->" button when you are finished. This will take you to the main screen where you can manipulate the weights for positions 2-11 (Plane weight cannot be altered since it is a fixed amount.).
3. MAIN SLIDER VIEW:
Here we go, this is the page you've waited for! Select a position to adjust (Pilot, Fuel, Station 4 etc) using the gray selector buttons. Use the slider at the bottom of the screen to adjust that weight. Use the nudge +/- buttons on the left/right of the slider to adjust weight by 1 pound. Tap a text box and the keyboard will appear to enter a specific value.
There are two "rings" that each slide on their own black bar. When you adjust a weight for a station, the iPhone/iPod Touch/iPad runs the calculation and displays the new center of gravity. If either ring is outside the CG envelope you entered on the previous page, the ring will turn red, red text error messages will be displayed and the slider will turn red. If both rings are within the CG envelope, the rings and corresponding text will be green (US) or blue (Metric). There is also an overweight error message that appears if your combined wight exceeds the value you entered on the previous page.
All of this happens in real-time and you do not have to return to the previous page unless you need to change the ARM, CG envelope or max weight values. See the "Videos" page for a demonstration.
4. MULTIPLE PLANE NAMES:
You arrive here by selecting the "Plane Names" button on the Enter Values page. Select a text box and type the custom name for up to 5 planes. Press "Save New Plane Names" to keep your entries and return to the Enter Values page. Press "Cancel" to abort and return without making any changes.
Fuel capacities have been increased since the original CG Finder App. You can now choose between the original 500 Lbs. or 2000 Lbs. US (2000 or 8000 Kg. Metric). The choice has been provided because the larger capacity causes the slider to have a more course control. Since all other stations were 500 Lbs., all stations behaved the same - the same slider throw for each.
5. STATION NAMES:
You arrive here by selecting the "Station Names" button on the Enter Values page. Select a text box for the station you wish to change and enter a custom name. There is a 7 character limit so you may need to abbreviate at times. Press "Save New Station Names" to keep your entries and return to the Enter Values page. Press "Cancel" to abort and return without making any changes.
FINDING THE CG OF OTHER OBJECTS:
1. Find the weight of each end of your object in pounds (Lbs). If you cannot find the weight of each end separately you cannot make an accurate calculation. A bathroom type scale will work for most household objects. Let's say you need to find the center of gravity of an aluminum extension ladder that weights 30lbs and is 24' long. One end may have a pulley and the other end may have feet so the CG will not be exactly in the middle. Lift one end onto the scale and make note of the weight. Let's say it is 14lbs. Move the scale to the other end and weigh that end. Let's say the other is 16lbs.
NOTE: In order to weigh each end you, obviously, must set some portion of the object on the scale (perhaps 1" at the very least). You must remember how much of the object is placed on the scale when you get to step 3.
ALSO: CG Finder only deals with whole pounds. Fractions of pounds will be rounded down to the next lowest whole pound. It will not accept "0" as an ARM value.
2. Choose a starting point. Choose any fixed point on the object to measure from. This point is called the datum. Usually this is one end or the other so that you always deal with positive numbers but any point will do. A datum inside the object will require some multiplication of negative numbers. It's your choice.
3. Measure the distance from the datum to the center of each portion placed on the scale. This will give you two "ARM" values. In our example, the first ARM value will be the center of the first amount placed on the scale. If you placed one inch of the ladder on the scale for each end and your are using one end as the datum, the first ARM value will be .5" (the center of the first inch) and the other will be 287.5" (the center of the opposite inch). Remember that it is a 288" long ladder. If you placed 6" on the scale the two ARM values would be 3" and 285". You do not need to place the same amount on the scale for each end. You could use .5" for one end and 3" for the other.
4. Enter your values into the CG Finder App. Since this app is meant for airplanes, you may want to skip the first three fields (Plane, Pilot & Fuel) and start with the fourth. Enter the two ARM values (.5 and 287.5) in the 4th and 5th ARM boxes and the two weights (14 and 16) in the 4th and 5th weight boxes below. No other boxes need to be filled in.
5.Calculate. Press the "Continue-->" button. In the center of the next view you will see "Current Takeoff CG" which says 153.57". To find the center of gravity of the ladder, measure 153.57" from your datum towards the center. Your ladder has an even amount of weight on either side of this point.
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