Calculate pitch balance of RC glider? Today, I played with styrofoam gliders with my kids; I made an asymmetric  wing, asymmetric horizontal tail, symmetric vertical tail, and attached these to one stick for the fuselage.  I've had big problems with pitch stability, so I played with adding mass to the nose, hoping to solve the problem.
Every time I throw a glider with my hand, the nose lifts up or falls down (which one depends on where I set the glider's center of gravity), and the glider crashes.  I set the tail to produce downforce, but I can't find the right pitch balance to make the glider fly well.
I know that, for level flight, the CG has to be in the same place as the glider's overall center of lift (both wing lift + tail lift).
Should the horizontal tail have a symmetric or asymmetric profile, and what should the angles of incidence for the wing and tail be?
Maybe the best way is to put the CG at the wing's center of lift (at the 25% chord line) and set the tail to a neutral position (producing no positive or negative lift)?
What is the easiest way to calculate where to place the CG if I don't know how much lift is produced by the wings and tail?
Joe Ayoob's world record throw of the John Collins designed paper airplane is worth watching over and over again.

Every time I throw the glider with my hand ...

This caused me to split my free flight hobby into throwing gliders and launching from a hill.
A thrown glider experiences a wide range of speeds in flight, therefor it cannot be set with a staticly stable &quot;tail downforce/weight forward&quot; arrangement.  This type of glider will loop if thrown hard, but will be fine if thrown off a hill.  Try to gently release it at its trim speed.  Moving the weight/changing tail decalage will produce the best glide.
But for throwing on flat ground for distance the glider must be slightly staticly unstable to keep flying as it slows down.  You want it to gradually pitch up (increasing AOA) as it loses speed to generate adequate lift for level flight.
The plane flies straight out until it stalls.  Notice on Joe's throw the glider went around 150 feet, from 40 mph to maybe 5 mph, stalled, then recovered from the dive, flying on to the world record.

Glider has asymmetric tail, which produce downforce, then glider is &quot;tail heavy&quot;

An asymmetric tail will produce pitching force aerodynamicly, not by weight.  This is why &quot;classic&quot; aircraft design has an &quot;upright&quot; vertical stabilizer (many glider designers also benefit by putting the horizontal stabilizer on top in &quot;T&quot; fashion, increasing pitch torque without adding drag).  The tail must produce a down pitching force to &quot;set&quot; wing AOA if CG is forward.
For &quot;throwing&quot; gliders, you need tail upforce, weight aft (while maintaining directional stability), and some luck to go 226 feet. If one can control the elevator (by R/C) in flight, then discus launched gliders (DLGs) are worth a look!