I have a goldberg piper cub and noticed it has a tad of upthrust on the O.S. .46 AX engine. Can this upthrust cause my cub to stall easier on takeoff as opposed to having some downthust in it if it doesn't have plenty of ground speed to begin with?

Or, what are the negatives of having upthrust in an engine period?

I need to know before I smash it up again on takeoff. []

Please reply,

It will tend to make it want to nose up easier and if you're not on the sticks to hold it back then it could lead to a stall. As a new pilot it's likely more about your lack of experience at this point but altering the thrust line for downthrust would be a big start to helping things go smoother at this stage. I'd suggest you alter it so that the prop is roughly 2 degrees downthrust compared to the flat of the wing's lower surface. That'll be more like 3 or 3.5 degrees of true downthrust but it's esier to check.