Use the Excel spread sheets for your configuration posted on the Cave to make the Weight and balance process simple.
Weighing the Aircraft
Scales
We have had excellent success with, and recommend high quality “race car” scales that have been recently calibrated. They are easily available in most area if you ask around. Many EAA chapters have them as well as many race car shops. Many Larger FBO type maintenance facilities have them and will assist with the W&B for a small fee. This is one area the Panther folding wing option is really helpful as you can “take it to them”. The most important aspect of the scales is that they are repeatable, and have a linear output. Meaning the read somewhat accurately from 30 - 400 lbs. qty 3 load cells make it easy, but with a little more work qty 1 can be used.
Weighing Procedure
1.With the aircraft inside free from wind, Level for weighing. Use a long level on the upper longeron in the cockpit area as a level point. If you have only one load cell you will need to make 2 shims the same height as the load cell to place at the other two points.
2.Weigh the aircraft empty with no fuel and normal engine oil level. (remember to close canopy)
Record the left front, right front, and tailwheel weights in your aircraft log books
3.Sit in the Aircraft with the seat back in the desired location, and either seatback cushion, or backpack parachute on, and canopy closed. Have a helper record weights. You can adjust the seat to other location and noting the hole positions and record new weights to generate several pilot arms to use later.
Measuring
1.With aircraft level exactly as you weighed it, drop a plumb bob down from the wing leading edge at the fuselage side, and accurately make a mark on floor for both leading edge location, and fuselage side. Repeat for other side.
2.Mark the center of tail wheel on floor.
A.You can either reposition your “tailwheel stand” (making sure the aircraft is still level) and us a plumb bob.
B.Or, you can use a tail forward offset .Measure forward a set number of inches from tail wheel center to a point several feet forward and on tail cone lower skins centerline. (We suggest 50”, but it isn’t critical as long as you add the same amount to your measurement in later steps) Drop a plumb bob from this point and mark both centerline and tail wheel forward offset on floor.
3.Use a Square to mark the centerline of each axel on the floor
4.Move aircraft if needed. With a chalk line or straight edge connect the leading edge marks from step # 1. Extend this line out so you can measure to the main wheel axel centerline marks.
5.Measure from the tail wheel center line (#2, A), or tail wheel forward offset (#2. B) To the “leading edge of wing” line at centerline from step #4. Add tail wheel forward offset if use, then add 60 inch’s and record in aircraft log book as tail wheel Arm (this should be between 226 and 231 inches).
6.Measure from left main gear axel center line to the wing leading edge line from step #4. Add 60 inches to this and record in aircraft log book as Left Main Wheel Arm. Repeat for Right side and record in aircraft log book as Right Main Wheel Arm.
