I could land my dazzler very slowly with relatively high nose approach.
i move the cg back (as far as the manual allows) and since then the same landing approach causes the model to stall.
in this case i have to use more engine power or to land much more flatted.

does moving the CG back causes the increase of the stall speed or there is other explanation ?

thanks

No, moving the CG back didn't increase the stall speed but it did make the plane more pitch sensitive. So much so that the plane may tend to pitch up as the angle of attack increases and possible pitch down as it decreases. This all becomes more pronounced close to stall or landing speeds. Using power and flattening the glide slope is a typical way to manage this. Or move the cg forward which may be undesirable depending on how you fly the plane

Denis

If you move the CG behind the center of lift of the airfoil then you are requiring the horizontal stabilizer to help 'lift' that weight in order to fly level.

The slower you fly the less lift there is available from the horizontal stabilizer.

So when you are flying at typical flying speed (fast) the horizontal stabilizer is able to 'lift' the weight easily and you do not notice a problem.

At a slow landing speed the horizontal stabilizer is less able to to 'lift' the weight and you are experiencing the result of that reduction in horizontal stabilizer lift. Thus it is required to find some way to provide enough additional airspeed so that the horizontal stabilizer can provide enough lift to allow a controlled landing.

To exaggerate this imagine moving the CG back so far that it is now half way between the wing and the horizontal stabilizer. The wing will provide lift as usual but the horizontal stabilizer would need to provide a great amount of lift just to make the plane fly level.

as i know 3d models which can't execute a decent harrier are required to move the CG back.
so in order to fly the model slowly with the nose high (without stalling) the CG is moved back.
is it not contradicting my model behavior ?

thanks

I think I understand a little better what your struggling with. Ignore my first post. It's not wrong but Keith's is much better for the purpose.

I assume you are trying to fly straight and level at a very high angle of attack but not hovering. You can do this with a fully stalled wing, partially stalled, or flying wing. Remember a stalled wing still produces lift but has a real bad lift to drag ratio and controllability problems.

The the thing your struggling with is not whether the wing is stalled but where the CG is with respect to the center of lift. In a stable plane the cg is forward of the center of lift and as the airspeed increases it causes a pitch down moment. If the cg is aft of the center of lift increased airspeed cause a pitch up moment or with a reduction of speed a loose of lift on the horizontal stab and a resultant pitch up, unstable. This is probable what you are seeing. when you increase or decrease speed you see the nose come up, the speed drop, the airplane start to fall and you interpret this as a stall. You probably were already flying in a stalled condition but that's not really important. What's important is how to use the elevator with an aft cg. I have two planes that are real bears to land when the fuel tanks are empty because of this. Very slight AOA changes cause large moment changes in pitch that take quick reactions on the elevator to control in slow speed flight.

I hope this helps but these forums are tough for this kind subjects.

Denis

for what this is good for , i fly with a very aft CG. If im not harrier landing i just put a few clicks of down trim on approach and keep a little power in it. works great for me.