Is my thinking wrong that if my plane will just barely go full vertical, that the static thrust of the engine/propeller is therefore about equal to the gravity weight of the plane?

Your thinking is correct

It's not just the static thrust that's not adequate. Leave off the "static" and your engine/prop's thrust isn't adequate.

Static thrust is just the best measurement we have available to suggest what will happen in the air. What we get in the air is just called thrust.

Not a big deal, but you asked for understanding.

Thanks... It seems to me that some real confusion exist when various thrust numbers are offered. Numbers are often offered from a horizontal test bed and it seems to me that while the scale they use is calibrated in lbs of gravity, the method is wrong because the scale is calibrated to measure lbs of gravity in the vertical plain.

Shouldn't static thrust offerings be identified to which plain they are measured? Or, if they are measured in the horizontal, is there a simple formula to transpose the numbers to actual gravity?

Again, am I seeing this wrong?

Good clarification, da Rock!

Static thrust means the prop's baldes are working at the max AOA.

Once the plane start moving forward, the AOA gets smaller until reaching a min at top forward speed.

This happens because the air hits the prop at a smaller angle when the plane is moving.

No, the plane of reference is not relevant, since force is force, whatever the direction is that it is applied towards.

Gravity is just a force, which we call weight.

Thanks again. I grasp the nuance between static and actual thrust but that is not what I'm wondering. I've seen some rather high numbers it seems to me posted for static thrust figures and I'd certainly not impune the offerings, but do wonder about technique yielding the numbers.

To clarify... What I'm wondering is this. If a motor, prop and cradle weighed 10 lbs and was hooked to a scale in the vertical position and yielded a measurement of zero, the static thrust would be 10 lbs after factoring gravity weight of the motor, prop and cradle but what would the measurement be in the horizontal plane? Would the scale measure 10 lbs?

Sorry, I did not understand the question correctly.

Absolutely yes.

Yep... seems I was seeing it wrong. Thanks for providing some clarity.

You are welcome, AA5BY

Static thrust is often maligned as not being meaningful once the model leaves the ground. And on a sliding scale this is correct.

For models that are hovering or are climbing slowly on the prop such as 3D models in hover or during harrier style maneuvers static thrust is exactly what is at work on those models. On slower climbing powered sailplanes again the props are operating in a mode very near to the static thrust results.

But as the prop pitch gets higher and the speed of the model is higher than the value of doing static thrust measurements dwindles quickly. In fact once the prop pitch is high enough that the blades are stalled during the static run then static thrust results are pretty much meaningless. The added drag due to the stall consumes power that would have gone to producing thrust and will once in the air and the model's forward speed allows the angle of attack of the blades to reduce to an unstalled value. Until then the prop will be slower to accellerate and not produce as much thrust as the power consumption would indicate.

I would think there may be a slight differance because of the incoming air.  Airflow into the prop is somewhat restricted when on the ground.  Therfore I would think that a plane hanging on a prop in the verticle would have just slightly more thrust in the air.