Hi Charalampos,
I suggest that you look closely to determine if there’s a small piece of weather stripping, or anti abrasion tape esp. where the cowling or other sheet metal might rub or vibrate against an adjacent part. There isn’t anything central to the engine or propeller that will create that type of vibration.
I would also check to see if any of the inspection panels in the floor are loose, or if any of the screws aren’t tightened up.
Although the location is wrong to create a floor vibration, check for any looseness in the door or door trim pieces.
Get down under the airplane, clean the belly and look for loose fasteners.
There has been a warning to inspect the welded tubes that form the left and right rudder pedals. Check for cracks at the welds. Perhaps there’s a crack in one of the welds that’s creating the vibration.
Check those possibilities and get back to me.
Steve
