Dumb question

smooth_bill wrote:Since when do we modelers determine direction of prop rotation from behind the prop? That is just a confusion factor, that should not be mentioned here.

Regarding model airplane builders, our only consideration is which way to flip the prop for starting, or to spin it with a starter.

Prop labels can get a little confusing, but generally are not labeled with CCW or CW, and seldom if ever with RH, or LH.

Some shops label reverse pitch props "Pusher", because on normal CCW turning engines, they push a vehicle forward from the rear end of the engine and airplane. That was the original use for brass prop drivers, to minimize wear between the prop drive washer, and aluminum crankcase nose.

Bill

It is not the modelers that determine / define direction of prop rotation, but rather the prop manufacturers. In the case of the props we sell, it was Cox, over 60 years ago, that decided to define direction as viewed from the pilot's seat. Whether this is correct, still timely or subject to interpretation is, of course, open for debate.

It is just that, when listing our props, we have to let buyers know what direction their prop is intended to turn relative to their position. We have no problem to change the view to standing in front, effectively switching RH for LH and LH for RH but we had to pick one of the two and we chose the Cox view as, otherwise, someone buying a prop listed as RH and receiving one moulded with the letters LH will, undoubtedly lead to questioning this. To keep in mind is that, with the exception of our 6" prop, all our props are moulded on original Cox moulds and, if the mould has LH in the cavity, that is how the prop will be moulded.

Furthermore, we are in possession of over 60 years worth of Cox literature, drawings and sales catalogues and their documentation for props mostly is annotated with RH and LH for sales and manufacturing purposes. We simply continue with their view without taking position as to how it should be done today. Again, for marketing purposes, we had to decide whether to define the view as behind or in front of the prop; whereas neither view is wrong.

Then, after struggling for some time with customers unhappy that they received a prop (or starter spring) that is intended to turn in the opposite direction as they believed to have bought, we defined rotation in our listings and a complaint in this respect is now a rare occasion.

Lastly, rotation plays a role on multi-engine aircraft as well as control line flying and, in the end, boils down to personal preferences.