Bump removal on Grass Strips.

[phiggsbroadband]

Hi All, I have worked in agricultural and municipal contracting in the past, and know how hard it is to flatten fields or lawns. Even a 2 ton roller will not make any impression on a 12ft wide mound, but it is just about Ok for flattening mole hills.

I have flattened some lawns, using the process of folding back the turf, then extracting some soil and replacing the turf. This works well for most bumps.
I have also wondered if a soil corer could be used on a bump and remove the cores. Filling hollows is relatively simple, by just adding soil, with grass seed if necessary.

I must admit that I produced a cricket pitch type playing field by cultivating and then smoothing the bumps with a 36ft telegraph pole dragged behind the tractor... An Amazing Tool !

So the question is... what method is most widely used for airstrips? Where obviously long 'downtimes' would prevent ploughing, cultivating and re-seeding.

[dubbleyew eight]

in sandy soil a sheet of weld mesh towed behind a tractor does a good preparatory flatten. you need to turn up the leading edge to stop it catching.

again in sandy soil an old slasher is a mighty tool. you lower the blades and close the senses and just mow over the 'ills 'n 'ollers and over time it flattens them out.

did I say that some of this is pretty agricultural...

[DX Wombat]

Talk to the airfield staff at Duxford where the grass runway is second to none. :ok:

[piperboy84]

I have learned some hard lessons trying to build and maintain my grass strip. I hope my views can be of help:

1. A roller will not do jack **** in getting your field level , I have used em all, 1 ton , 3 ton and 5 ton, all they do is push down the stones and pack the surface sometimes so hard it restricts the grass growth, rollers have no leveling capabilities for the type of finish you want on a good grass strip.
2. If your field has undulations due to drainage, sinkage/settlement or that's just the way it was to start with, running around patching or spot filling areas is a waste of time. I now believe after lots of faffing around the best way to get it bowling green level is to first rotavate the grass to break up the clods of turf, then put a dozer in with a laser level (depending on how wavy the surface is you may have to push the topsoil to the side then re-spread it when finished leveling the field), do not relay on some dip**** digger driver claiming he can get it level from sight or feel, they can't! its impossible, a laser equipped dozer that gets its blade adjustment automatically from the laser is the only way to go.

I spent days after the field was ploughed pulling an H beam with weights on it back and forward, it only smoothed localized areas but overall would not take out the undulations, in fact it sometimes made it worse. I also tried a tow-able blade/scraper, that was a waste of time also. I also tried cambridge rollers with paddles of the front to drag a heap of soil hoping it would fall into the shallow bits but that was a waste of time also.

I own or have access to a 16 ton JCB slew digger, heavy duty loading shovels, monster rollers a 250HP ag tractor with every implement you can think of for cultivation, tried them all and it did not work if you want a really flat strip.

Bottom line: Laser equipped D8 or 9

http://www.youtube.com/watch?v=5XQMjluTrjg

[Nearly There]

Piperboy, many thanks for that info for a slightly different reason, we've a hovercraft track and have tried harrowing, power harrows, 8ton rollers, cambridge rollers, surface scraping using a blade and back filling and although we've improved the field a fair bit its still not what we want, the bumps can and have caused hull damage to our craft, I'd not heard of a lazer dozer till today but will be looking into it! :ok:

[dubbleyew eight]

piperboy is on the money.
getting a level surface is only one part of the story. you need to get even compaction of the soil under the flat surface or the next winter's rains will see it all become 'umps 'n 'ollers again as the water does its settling thing.

[Flying Binghi]

Seeing as yer already got a 'strip', probably just a grader and roller will do the trick. A large grader can do just as much soil moving as a small bulldozer.

Since the strips for hovercraft probably no need to worry about soft spots. Just knock of the high spots with the grader and yer away..:)







.

[phiggsbroadband]

Hi, I like the idea of using a L@sorguided dozer, but that involves at least 2-3 months downtime. It would also require some minimal scratching of the dozer trackmarks to get a seed bed for the grass, then a light rollingafterwards.

I think long undulations of over 100 yards may be acceptable,but the short bumps of say 10 yards, with a height of over 6-12 inchesare not. These medium size bumps still contain asignificant amount of soil, (about 6 JCB bucket-fulls), and arethe types to be found at nearly every grass strip in the country.

One airfield in the south that I recently visited had abump on the right hand side of the runway and none on the left,perhaps they were keeping the runway open by doing he job in twohalves.

It is possible to hire turf cutters, so that 60mm ofturf can be lifted. Then extract soil and replace theturf. But do not cut too shallow as the turf may bedislodged by the propwash of the first aircraft to power up onthat bit of grass.

See this utube video … SOD CUTTER.m4v - YouTube

[dubbleyew eight]

phiggs the test is to drive a car along it at about 50 mile an hour.
if that feels ok it should be ok to land on.

[chevvron]

Don't get it pregnant in the first place!

[gasax]

My local strip owner tried it all. Some measures help but note they only help. Eventually he bit the bullet, peeled back the topsoil, levelled the subsoil and then put the topsoil back and re-seeded.

It was done in two stages so the strip was still usable on one side.

However the major downside is that a number of people have been banned due to taking divots out of the new bowling green surface........