Re: Laser leveling

 

Hi Wal,

Firstly, the 18 mm limit is for recovery of the grass.  Depending on the weather, even as much as 15 mm cover can put the lawn out of action for up to 2 months.

With regard to accuracy, my background was in control systems design and modern hydraulic systems can respond very quickly, although I don't have any figures for the response of the hydraulic blade control for the leveling unit attached to a tractor.  In our case when leveling the lawn the driver makes many passes over the lawn at 90 degrees to each other and so I think that by the last pass the leveler blade would hardly be moving at all.  I therefore don't think that the blade response would be a significant factor in the overall accuracy.

I was interested in Max's comments about what they do at Narooma after they laser level.  I don't know how wide apart the rails would be but I imagine not much more than 2 metres which means it would be a long and tedious (and expensive) job to level a lawn in, say 2 metre wide strips at a time.  Perhaps Max would like to comment.

Cheers

Roger


On 8/12/2017 5:05 PM, Wal Mills wrote:
Thanks Roger,

I am familiar with lasers having used them on soccer and rugby league grounds with both manual staffs and attached to graders. In their case grades 0.5% and above were used but I was curious with flatter slopes and attached to tractors. My concern is the shorter blades with accuracy and more so in your case as there is only one laser receiver attached to the tractor. Secondly the laser/tractor accuracy, with many instruments in the range 1 to 4mm in 20 metre plus the response of the tractor blade, 0.2% sounds very interesting (0.04mm in 20 metres).

I assume the 18mm maximum depth is more for the grass to recover than the laser issue?

On another note our contractor has a scarifier attachment to the tractor which picks up the thatch and dumps it on canvas to put in trailers. There is also an attachment to spread topsoil.
Also the leveller is attached to our mower to drag around. Very little manual work.

Thanks for the response and videos.

Wal


On 8/12/2017 4:21 PM, Roger Evans wrote:
Hi Wal, Roberta and all

An (amateur) video of laser leveling of the Jamberoo CC lawn 1 in January 2015 can be seen at: https://vimeo.com/246384287 (just under 2 minutes long).

Unfortunately when the lawns were constructed they had a slope of about 0.6% (6 mm per metre) from east to west as well as a few hills and hollows so the programme has been to gradually minimise the slope and get rid of the hills and hollows by laser leveling every couple of years.  Commencing in 2010 we have laser leveled the No.1 lawn 4 times and have successfully removed the hills and valleys and reduced the slope to about 0.5% east to west (ie 5 mm in a metre).  Of course 5 mm in a metre equates to about 128 mm fall across the width of the lawn and, because there is a limit on the maximum thickness of top dressing of about 18 mm per leveling operation, it will take many years of leveling before the level can be reduced to below 0.2% (ie just enough for drainage.)

Cheers

Roger






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