Tip22v

Short of there being significant differences in the weight of the airframe itself, which is highly unlikely, it seems there can only be two possible explanations:

One is that folks are not actually balancing their aircraft the same way which means some folks think their at 200mm when maybe they are really farther forward than that. This could be explained by pilots having different interpretations of what nose heavy really feels like in flight so everyone thinks their jet is flying great the way it is. I use a XICOY CG computer, but it's only as accurate as the measurements I put in e.g. distance from front wheel to rear wheels. It would be interesting if a couple of folks with significant variation in battery placement both used the same type of CG computer with the same exact dimensions, that way we could take the human factor out of the equation to better understand why this is happening. I'm in the process of building mine, would love to compare Xicoy readings with someone when I get it finished.

Two: I've seen some variation from photos on where folks are mounting their turbines. Perhaps some folks are mounting slightly forward, whereas others might be mounting farther back. Also, the K70 is a few oz lighter than the K-60 and K85 so that might explain some of it as well (althought Loir, I believe you are using a K60, which is heavier than a K70 so that would not explain your situation). I'm not sure if this slight variation would affect the CG enough to require batteries to move that much but it's certainly worth considering. Another possibility is the other equipment being installed e.g. servos, servo harness and placement of things like the UAT receiver etc. I'm using the pre made wiring harness from PacificRC and I noticed it is not very light.