WING INCIDENCE?
 

Can someone explain me what is wing incidence?

Blind leading the blind...
 

Whee... here goes... my newbie impression of wing incidence is basically the angle of the wing relative to the line of thrust of the aircraft. Raising the leading edge of the wing (relative to the trailing edge) increases incidence, and lowering it decreases incidence. This is all fine and dandy for a symmetrical airfoil, but things get complicated with a flat-bottomed trainer type airfoil... if the bottom of the wing is flat (i.e. parallel to the line of thrust) you have a bit of positive incidence, since the "center" of the leading edge will be above the "center" of the trailing edge.

I'll leave it to the experts to correct my description, and tell you why you might want (or not want) positive incidence on your wing.

-Rick (fellow newbie)

WING INCIDENCE?
 

Hello Rick and Jucava:

rick is right about the wing incidence, however the horizontal stabilizer incidence must be correct for the design of the aircraft first. Always check the stab incidence with the center line on the plans first, then set the wing incidence relative to the stab. Consider the full scale LearJets or most other full scale aircraft of this class, they change the horizontal stab incidence to "trim" the aircraft for level flight at different speeds. the design of the model allows for the trim changes by trimming the control surfaces at the radio. So make sure the horizontal stab is at the correct incidence relative to the side view center line on the plans (the kits are not always cut correctly) the set the wing incidence to the value indicated on the plans. I like the Robart incidence meters. Once the model is leveled with th thrust line, the wing incidence is easily and accurately checked and adjusted . I have not used the new laser pointer incidence meters so I can't vouch for their accuracy.

WING INCIDENCE?
 

I've used the laser meters. They are much more accurate than the Robats and the laser meters can tare their zero reading which is a nice feature. I can easily see 1/8 degree changes or less with the laser meters.

Incidence really isn't measured from thrust line. It is measured from a datum, which is an arbitrary line the designer placed in the plans. It is common for thrust, wing or stab to be zero with respect to the datum, but not always. My point is don't assume engine thrust is at 0 degrees.

Probably the most important thing to remember about incidence it that it is has a dependent relationship with CG and stab incidence/trim. In other words, if you change wing incidence, it is similar to making CG and/or elevator trim changes.

Cheers

WING INCIDENCE?
 

I got it, thank's every body.