Mark Mark Mark,
Are you trying to confuse us?.
Not wanting to get into a slanging match but,
Reread post 3 as you suggest and did not come to the same conclusions you did.
As a layman, may I suggest to all, KISS is always appropriate in any commentary, my understanding of what the enumerated points in post 3 are referring to is "Tension" namely stretching between the two points which will then try to regain their original positons by eliminating that tension by compressing back to normal. I don't read that as meaning the forces applied being torsional/rotational.
However to be fair, there is a comment much later, of "tension/torsion".
This as far as I see it doesn't alter the tension, stretching applied to the nut and propeller connection referred to by all.
So in KISS terms why is post three and similar statements wrong and to be ignored?????
Not trying to confuse anyone, (unfortunately it tends to come unasked for
)
I'm not interested in a slanging match, but I will try and explain my to reasoning.
My main argument against Derek's postings is with his incorrect use of terminology, confusing the different forces involved in the 'locking nut technique' to the extent he picks one 'out of the hat'.
Now the following may appear as picky/pedantic/whatever - but it can confuse those who don't fully understand the terminology and then start repeating the mistakes 'as gospel' to others
While the forces "compression" and "tension" are not mutually exclusive, to describe the nut and prop, (I'm using the same 'components' as the thread), as being in tension is wrong. The nut and prop are in compression, so the shaft between the two parts must in tension.
The only 'torsional force' involved is, (basically), how hard you turn the nut against the prop to obtain the 'locking' effect.
Now take post #8 - I'll reply 'inline' in
red as it's easier that trying to quote/reply every point
mmmmmm... this is an interesting subject
1. the anti rotational torque [acting] on the propeller blade surface is the resultant of the applied input power - this applies equally to FWD or ASTERN rotation Very confusing torque can't apply to a blade surface - it applies to the prop-boss to shaft interface, but does apply to either rotation
2. these are complex calculations.......
3. if the resultant applied power [torque] exceeds the induced mechanical tension [torque] applied between the two components .....then yes something else will fail in the drive line Just a very confusing statement due to incorrect use of power/torque/tension.
4. however this does not include the loss of induced tension/torque between the propeller & the lock nut Again, incorrect use of the same terms - it's loss of 'compression' between the prop and nut
5. if you have experienced... 'the odd prop come off (usually only in the middle of the pond though)' ...please re-read & consider the points offered Easy to read and consider - not so easy to understand!
Please don't mistake me saying that Derek doesn't know what he's talking about - from 'reading between the lines' he knows exactly what he wants to say, but just tries too hard to use big and technical words and finally makes a right pig's ear out of it.
Mark.