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Hello,

I maidened my FW Stinger 90 deluxe EDF jet last weekend and have encountered a couple of strange behavior despite an overall satisfactory 2 flights that day....
Flew with a 6S 5200mA Battery both flights. First flight turned nose heavy even though i placed the battery exactly at the same place of a friend's Stinger that flies very nice and stable...
I experienced an uncomfortable feeling of twitchy sticks at times although had 25/30 % expo (flying with a Futaba MZ18 negative info just in case someone would ask).... in addition Stinger would climb distinctively when stick was pushed to full power!!

On second flight battery was moved aft C.G checked. behavior was a bit more consistent but same symptoms (climbing at full power) was experienced...
Did a CG test by climbing at 45deg inverted and there was the biggest surprise: Stinger would push inside towards canopy (inverted) heavily... an inverted flight also confirmed same tendency making it hard to maintain level flight without pushing a lot of down elevator. (i have enough experience, around 40 years of flying also sorts of RC planes including pattern, Turbine jets, Giant aerobatics... you name it). Must admit that this is the first time i encounter such contradictory behavior : Nose heavy syndrome according to CG test, twitchy controls (except for down elevator) symptom of a tail heavy plane....

Last but not least we have 3 other Stingers flying in our club and they all behave well (still need to check the inverted flight capabilities of my friend's Stingers hopefully this week end....

Appreciate input from people who own and fly this nice jet....

Thanks

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"!

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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

Extreme_RC

There have been a few foamy jets over the years with Cg or incidence issues, mistakes in manuals are a pain as you are fighting the gut feeling vs the manufacturer who you would hope got it right. I would ignore the resident troll, there is a distinct lack of aeronautical understanding in that one, should be fairly obvious from the narcissistic chain posting that goes on in here...

Joseph Frost

The one would expect that someone with 40 years of experience, Quote- (i have enough experience, around 40 years of flying also sorts of RC planes including pattern, Turbine jets, Giant aerobatics... you name it). especially flying "Pattern-ships", the foundementaly base model, would know how to set up a generic foamy trainer like "Stinger 90", just by looking at it, not to mention with help of 3 other members flying the same thing.