Clockit

I am about to start assembling a CMPro Swallow 90 and need to find a way of measuring the incidence of the wing and stab. I would like to start off with a "0" incidence on the wing and stab and work from there. I have a digital incidence meter but need to start with a known level before starting with the wing

Any ideas on how to proceed here would be great

Rotaryphile

You need to establish a datum line along the side view of the fuselage, usually through the propeller axis for powered airplanes. The exact path of the datum line is not important, since it is used only as a reference. As long as wing and stab incidences are changed equally, as well as thrust angle (up or down), in relation to the datum line, everything should be just fine. The airflow over the airplane cares little about the up or down angle of the fuselage as if moves through the air, since the lift required of the wing will determine the angle of attack, and the fuselage simply follows, passively. Positive incidence is normally used on full scale airplanes simply to make the airplane fly with the fuselage slightly angled down, simply to give the pilot better vision over the nose.

If vision over the nose is not a consideration, I would angle the datum line such that it appears to force the fuselage to adopt its minimum drag angle in full speed flight.

Clockit

Thanks for the info.

Since this plane will be used for pattern, I assume the incidence must be zero or as close to zero as possible?

One train of thought would be to fit the wing and then aline the stab to the wing. My concern is determining the thrust line of the motor in relation to the wing and stab - or is this not something which I should overly concern myself about?

Again, thanks for the advice

perttime

Does'nt the manufacturer of the Swallow give any suggested angles?

As far as I can tell, pattern planes tend to be pretty close to 0-0 between wing and stab but there are small differences between different designs. Engines usually seem to have a couple of degrees down and right thrust. There are trimming instructions around for fine tuning the plane but this is done by flying specific manouvers to see if slight changes are needed in incidence, balance, dihedral, thrust angle, mixing, ...

pimmnz

Start by jigging the fuslage so that it is basically `level' horizontally and laterally. Set the thrust line to the same measured angle as the tailplane. It does not matter what the angle is, so long as they are the same. This will set your `0-0 datum'. You can now rig the main wing at this angle or 1~2 deg positive to this angle, depending on what you intend the model to do. And that is basically it.
Evan.