RCU Forums - View Single Post - Freewing 90mm Stinger Deluxe Strange Behavior!!!
Old 05-04-2019, 11:26 PM
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Originally Posted by Joseph Frost
Mate, after 40 years of flying experience I would expect people giving advice, (Q-40 years of flying also sorts of RC planes including pattern, Turbine jets, Giant aerobatics... you name it). not asking such simple question, it says enough. re-trim your "Elevator"!
Joseph,

If you think that you can stop learning at a certain point of life and consider that you know everything would be presumptuous which I am not...
I guess my past experience was the triggering factor behind my query searching for an logical explanation for this weird behavior for a well known straight forward kit that doesn't need a genius to assemble and put in the air. Furthermore, experience can even tell you what to expect on your maiden or at least be prepared for eventualities....
Well, I was finally able to find a forum on the internet (about 575 pages+) talking about the Stinger in general and the CG issue in particular...
The problem turned out to be a misinformation on the instruction manual.
To make a long story short, battery had to be pushed all the way aft in addition to adding up to 2 oz of lead in the tail in some cases (depending on the capacity and C of the batteries).
Correct CG had to be moved aft by 20/25mm (from the CG location listed in the manual) to achieve proper balance and have coherent flight characteristics...
Above modification was verified yesterday and proved to have solved the problem. 3 other stingers also modified their CG and enjoyed the improvement greatly. Stinger was "transformed" after solving the issue.

Cheers