Center of Gravity
The correct center of gravity for the JW60 is 2 5/8" back from the leading edge where it meets the fuselage. Older versions of the instructions indicated a different CG location, so please take note of the correct CG for your first flights.
Center of Gravity:
- JW30 = 1 1/2"
- JW36 = 1 3/4"
- JW48 UL = 2"
- JW60 = 2 5/8"
- Sonic = 7 1/4"
The dive test is the best way to tell if your JW is nose heavy or tail heavy. To perform the dive test, first trim your JW for level flight and adjust your elevator trim so the plane is flying flat and level. Climb to high altitude and then dive at a 45 degree angle without using any stick input. Notice if the plane has any change in pitch. A nose heavy JW will want to pitch up during the dive test. A tail heavy JW will want to "tuck" or pitch down during the dive test. If the plane passes the dive test, then your CG is correct.
A perfect CG works for all disciplines of JW flying. A neutral CG will improve front side aerobatics at slower speeds. A very slightly nose heavy plane will be easier to control at high speed but at the expense of aerobatic maneuverability.
Never fly with an aft CG. The plane will be difficult or even impossible to control. A very slight amount of aft CG ( <0.5mm ) should only be attempted after the plane has been thoroughly tested at the correct CG and only if the pilot is skilled in flying neutrally stable aerobatic ships.
Pilots new to dynamic soaring will benefit from a slightly forward CG while learning. As the DS skills improve over time, the CG can be adjusted incrementally to allow the pilot to adapt to the increased control rates and decreased stability.