RE: Landing Gear Direction
The gear needs to be in the proper location in relation to the CG and what surface you're using i.e. taking off and landing on grass or concrete/asphalt. For trikes, as mentioned above, having the gear too far back will prevent rotation. For tail draggers, having the main gear too far back results in nose overs. Too far forward and you'll bunny hop down the runway on landing. Not fun. It really is a joy to fly a properly set-up model and just a chore when things aren't right.