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new videos of granary model

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scubi63 S
scubi63 Mar 11, 2008 13:26:16
Replying to beatles

Hi Beatles

Firstly I am no expert on either this sort of engineering or indeed on Stonehenge itself so my apologies if this sounds a bit dumb.
Secondly I must admit to not readying the article thoroughly as I am at work at it is not easy to do.
The video of the model shows that it is very susceptible to variation in wind speed and I imagine the full scale would be the same but that the inertia would be much greater.

My questions are:
To control the speed how would the sails be pulled in or let out while it is moving?
If somebody was to get caught in the rigging or in the rollers how would such a heavy structure be stopped suddenly e.g. how is all that energy suddenly released?....or wouldn’t they worry about that?
If the wind is blowing hard enough to turn the sails how do you keep the grain from blowing all over the place?
What would the sails have been made of so as not to be too heavy, especially when wet.
Is Stonehenge a perfect circle and perfectly horizontal to allow such a structure to turn freely without there being so much slack that it just becomes unstable as it speed up (bit like a speed wobble on a motorbike for those who know)?
Differences in weather conditions (temperature, humidity etc) would change the stresses on the ropes and wood and probably not in an even manner all around the structure. How would they stop the structure from being over stressed one moment and too slack then next to the point where it just breaks (I think this is related to the previous question)?
I can tell from the video where the pivot point is but I imagine it is at ground level in the centre. As the structure turned it would create a lot of heat on this pivot point (similar to when Ray Mears light his fires by rubbing two boy scouts together) and would require a lot of lubrication to keep it moving. Is there evidence of heat generation/ in the centre of Stonehenge?

Personally I think this idea is all good fun but I can not see this much effort being put into creating both Stonehenge and this sail structure just to grind grain. It seems to me that if you were going to use this design (and I wouldn’t), it would have been easier to have created a series of smaller structures that would be more maintainable and would not put all your eggs into one basket (as it were).

:o)

Scubi.

B beatles
beatles Mar 11, 2008 15:49:10
Replying to scubi63

scubi63 wrote:
Hi Beatles

Firstly I am no expert on either this sort of engineering or indeed on Stonehenge itself so my apologies if this sounds a bit dumb.
Secondly I must admit to not readying the article thoroughly as I am at work at it is not easy to do.
The video of the model shows that it is very susceptible to variation in wind speed and I imagine the full scale would be the same but that the inertia would be much greater.

My questions are:
To control the speed how would the sails be pulled in or let out while it is moving?
If somebody was to get caught in the rigging or in the rollers how would such a heavy structure be stopped suddenly e.g. how is all that energy suddenly released?....or wouldn’t they worry about that?
If the wind is blowing hard enough to turn the sails how do you keep the grain from blowing all over the place?
What would the sails have been made of so as not to be too heavy, especially when wet.
Is Stonehenge a perfect circle and perfectly horizontal to allow such a structure to turn freely without there being so much slack that it just becomes unstable as it speed up (bit like a speed wobble on a motorbike for those who know)?
Differences in weather conditions (temperature, humidity etc) would change the stresses on the ropes and wood and probably not in an even manner all around the structure. How would they stop the structure from being over stressed one moment and too slack then next to the point where it just breaks (I think this is related to the previous question)?
I can tell from the video where the pivot point is but I imagine it is at ground level in the centre. As the structure turned it would create a lot of heat on this pivot point (similar to when Ray Mears light his fires by rubbing two boy scouts together) and would require a lot of lubrication to keep it moving. Is there evidence of heat generation/ in the centre of Stonehenge?

Personally I think this idea is all good fun but I can not see this much effort being put into creating both Stonehenge and this sail structure just to grind grain. It seems to me that if you were going to use this design (and I wouldn’t), it would have been easier to have created a series of smaller structures that would be more maintainable and would not put all your eggs into one basket (as it were).

:o)

Scubi.

thanks for your questions. quite a few.
in the model, the sails are pre set but in the full size mill men would be riding the carousel and setting the sails by hand to control the speed. and yes it was dangerous but not as dangerous as erecting 20 ton megaliths.
stonehenge was almost a perfect circle (to within a few inches) and perfectly flat on top of the sarsen ring eventhough the ground at the site is tilted.
yes crude ropes stretch and sag just as on early sailboats and would have needed to be adjusted at times. not a huge problem. people were well aware of sailboats when stonehenge was built.
the pivot point of the carousel is at the top of the central post not at ground level......it consisted of a wooden and rope collar. it did not have much force on it since the weight of the carousel rested on the sarsen ring

and yes this is a lot of fun.

clyde