... apologies if I confused the issues .... don't worry too much about the points I raised .. the only intent was to suggest that it is not just a matter of considering the bump as a garden variety sort of bump in the runway of life ...
The main consideration relates to the overall pitching moment to which the aircraft is subject... if this is nose up then the pilot will need to correct with a touch of forward stick .. and the reverse if it is nose down. ... but the situation will, quite likely, vary among aircraft and specific circumstances ... while I admire the confidence shown by our colleagues who have put forth definite statements .. I feel that such statements have presumed assumptions underpinning them ...
If the aircraft is firmly on the wheels, then we are interested in the moments about the wheels ... if in flight (or with negligible load on the wheels) then the cg becomes very relevant.
If you reflect back to your PPL studies in PoF or weight control, draw a piccy of an aircraft in the circumstances you describe and then think about ALL the forces which might be acting on the aircraft and WHERE they are acting ... this permits you to figure some moments (the old force X arm trick) and the sense (nose up or down) of the moments ... figure the subtotals of nose up and nose down .. and the bit left over gives you an indication of what the aircraft is likely to do statically .... the subsequent dynamics of the situation get a bit more complicated, though ....
... and if you are in the typical leaf spring undercarriage Cessna .. then, unless the bump be of prodigious size .. you are not really going to notice it at all .... the wheels just keep on merrily bouncing up and down ....
The matter of undercarriage characteristics is very important ... most people have no idea just how involved, for example, something as apparently simple as altering a tailwheel assembly might be when it comes to the engineering assessment of loads and load paths in the back of the bird ...
At the end of the day .. if the aircraft is reasonably conventional in its characteristics ... the typical bump isn't going to present a problem ... the pilot will make whatever correction might be necessary typically without even thinking about it ...
If your experience has been limited to nice smooth runways, then I can appreciate your concern .... but do have a talk with some of your paddock operating brethren ..... at times the wheels can become quite a blur during the ground roll ...
Last edited by john_tullamarine; 22nd August 2002 at 00:42.