thanks guys fro your reply and support.

Yesterday i went on field for an "on air" prop testing :

the weight is 720g
testing has been done on two props, 9x7.5 APC and 8x8 APC ( sorry opjose but my shop didn't have 7x6 and 8x6 but they'll arrive soon )

take off went fine and reached a good levelled flightat 40% ( for sure less then half stick) of full throttle , it happened that
the plane "on level flight" as soon a si give 1% - 2% throttle more , drastically tryies to goup vertically like if it has an elevator fulldown ( onTX)
by dropping down the throttle again at nearly half stick it levelled perfectly straight , is this a problem of weight or baricenter ????


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