Re: Parking aircraft without towbar
PostPosted:Mon May 10, 2021 10:05 pm
Flying_john wrote:Dodo wrote:Perceived wisdom is not to push down on the tail/rear fuselage to lift the nosewheel to turn it.
Something about the structure, but I'm not entirely sure why. I do it occasionally.
Why is this - since in flight the downwards aerodynamic force on the tail has to balance the mass of the engine and everything else forward of the CofG and the main gear is normally quite close to the CofG I would have thought the structure is strong enough to balance that additional load, otherwise we would all have to be very careful in a steep climb?
It's not the load on the structure that's the problem; it's the pressure on the individual hand or fist -sized bit you're pushing on. Aerodynamic force is spread over a wide area but your hand isn't.
Another way of looking at it: aerodynamic forces hold the wings up in flight, but if you try to hold the plane up by using the pointy end of a pointy screwdriver on the wings, you'll punch holes in them instead. The difference is in the pressure being applied. In the same way, you can only apply significant force on a part of the structure that will be able to cope with it. I can't speak for your aircraft, but usually I find that means doing as much as possible to spread out the force when pushing anywhere, and even then being quite careful not to dent or bend things.