The problem is here everywhere in the industry : One experienced guy build a prototype and validate it by mean of extensive tests and fly test for our purpose. Everybody can found on the tube some videos of Ali testing the boomerang with far overshooting of normal flight for thoses planes.

The problem start when you want to produce this prototype in great series. That mean producing hundreds of the same plane, assembled by low experienced people (whatever the nationality is). What you need is a very good quality system to control that what you are producing is what you have validated first !

You can't imagine how the production system can change thing which seems "non-important" for them. Such as verify the good temperature to cure resin, enough time to dry it, or use the specified glue and not something "equivalent half the price which is in fact non-equivalent"... I've seen some RTF kit (non-jets) glued with only points of glue in place of continous joints ! It's far quicker to do than ensure correct gluing and it was internal !

Here we have those questions :
- Does FEJ ensure that their models are correctly designed as prototype (video of tests ?)
- Does they ensure all the production models will fly as specified ?