max speed for moderate and severe turbulence? (flight manual gives me the recommended air penetration speeds but it doesnt say for severe or moderate turbulence) so not to sure..
If there isn't a different number, I'd imagine it would be the same. That being said, severe and even moderate turbulence is
not something you want to be flying in in a 172. If there is severe or moderate turbulence this will be outlined in the ARFOR or SPECI and I would seriously reconsider going if there fell on my route.
what is the limiting factor for crosswind?
For a high wing aircraft it's usually when you run out of rudder and/or aileron to keep the aircraft straight. For a low wing it's often the height of the wing above the ground. For some twins, it can be the height of the propellor.
How did cessna arrive at their cross wind figure for the c172R?
Often the crosswind figure in the POH will be defined as 'Maximum
Demonstrated Crosswind Component'. This is the maximum crosswind that was used in flight testing.
factors that influence a particular figure to be nominated as Vne for an aircraft???
Since Vne is the point at which structural failure can occur, the structure of the aircraft, how it's built etc will contribute to this. There is also a safety factor added, but you should
never go above red line.
what is the max carb/heat drop in rpm? (havnt flown in a carb heated aircraft yet).
This should be in the POH or checklist for the aircraft. The RPM will drop when you put carb heat on because the air coming in will be warmer and therefore denser so the fuel/air mixture enriches, lowering the RPM.