mazvaz.....sorry....I am not familiar with the plane. But 75 grams is ALOT of extra weight. I would guess that the extra power required to get and keep the plane aloft would counter the prolong flight times as you are having to consume much more power. If someone knew the wingloading and thrust rating of your motor you could probably check on paper whether or not you could fly it......or you could try with current battery and add weight to simulate the battery........then fly. A little less precise and scientific...but you could know before buying the battery whether or not it will even work. Just a thought......

Shane
...now where did i leave that epoxy?