Gludy
Well-Known Member
Brendan
"Gludy, you never responded to my comment very early on in thread that research shows that props vary in whether they cause more or less drag when freewheeling or stopped, depending on many variables. A PhD student did this as research. So I still maintain, it depends, not absolute. "
I maintain it is absolute - the only experiment listed on this thread shows that a university measured the direct difference between free wheeling and fixed and in that case the freewheeling gave 30% more drag. It cannot depend on hull or anything else. Whether it is worthwile locking the shaft and running on a single engine - the subject I started this thread on does depend on engines, hull etc but not the question of if a freewheeling prop produces more drag than a fixed prop - that is the same regardless of prop or anything else.
It is also a simple scientific fact - a dragged prop is forced to have a much greater amount of water pass over its blades than a still prop - if this was not the case then props would not work as props when driven by an engine .... there is no way out of the absolute fact. Direct drag measurements done by the univerysity totally support this. To argue differently is to really be a flat earther.
"Haven't got the link to hand, but have posted it many times before on similar threads if you want to have a look at the research data first hand. "
I really would have to look at the experiment - I cannot comment on it without seeing it. All we have from you is a claim that an experiment was done without any details of what it was - how it was performed etc. To deal with this question it would have to examine just the one point - does a dragged freewheeling prop exert more drag than a dragged fixed prop - if it even introduces other factors then the basis of it is wrong. The answer is already known to science so there is little point in doing it - also its hardly the stuff of a PhD because it is a simple experiment.
So please provide the link to this thesis and I will comment further.
"Gludy, you never responded to my comment very early on in thread that research shows that props vary in whether they cause more or less drag when freewheeling or stopped, depending on many variables. A PhD student did this as research. So I still maintain, it depends, not absolute. "
I maintain it is absolute - the only experiment listed on this thread shows that a university measured the direct difference between free wheeling and fixed and in that case the freewheeling gave 30% more drag. It cannot depend on hull or anything else. Whether it is worthwile locking the shaft and running on a single engine - the subject I started this thread on does depend on engines, hull etc but not the question of if a freewheeling prop produces more drag than a fixed prop - that is the same regardless of prop or anything else.
It is also a simple scientific fact - a dragged prop is forced to have a much greater amount of water pass over its blades than a still prop - if this was not the case then props would not work as props when driven by an engine .... there is no way out of the absolute fact. Direct drag measurements done by the univerysity totally support this. To argue differently is to really be a flat earther.
"Haven't got the link to hand, but have posted it many times before on similar threads if you want to have a look at the research data first hand. "
I really would have to look at the experiment - I cannot comment on it without seeing it. All we have from you is a claim that an experiment was done without any details of what it was - how it was performed etc. To deal with this question it would have to examine just the one point - does a dragged freewheeling prop exert more drag than a dragged fixed prop - if it even introduces other factors then the basis of it is wrong. The answer is already known to science so there is little point in doing it - also its hardly the stuff of a PhD because it is a simple experiment.
So please provide the link to this thesis and I will comment further.
