Constructing a grass strip

[Guest nunans]

Will be operating tri gear out of there, mainly the Jab 230.

Yeah i think if i were to fly a jab out of my strip the wheels would still be shaking the next day.

 

 

[flyhi]

A grader will do a better job than say a blade behind a tractor or a dozer because the blade sits midship between front and rear wheels which are further apart than a tractor thus ironing out more of the ups and downs... at least thats my experience anyways.

Yes Bigs.5128 that's the way I did it. Got the grader in first to prepare the surface. Most of my operation now is in the Tecnam with the standard 500 x 5 and you need the surface as smooth as possible.

 

 

[facthunter]

A blade hanging out behind a tractor just makes a mess of it. You need a set of flat steel wheels, at the rear with a 1 inch steel rim on one side of each to prevent the thing going sideways when you angle the blade. which you need to do to form the surface. I bought mine. It was a Barford. really ancient thing that would have been used for roadmaking. tow behind a tractor with the usual 3 point linkage for height adjustment ( minor) For large ones move the blade. A good heavy slasher set low at the front will do a bit of levelling over time . Nev

 

 

[boingk]

Think people misunderstood my post... I was trying to describe what a grader looks like to somone who asked a question about them.

 

Using a blade will be useless, I'd *Highly* recommend using a grader!

 

Can be as complex as this:

 

 

Or as simple as this:

 

 

- boingk

 

 

[facthunter]

pictures are better than 1,000 words. Nev

 

 

[turboplanner]

FH, I'll have to show you how to use it then - you're obviously used to sliding the old Indian sideways with a boot out to kick away the clods.

 

I agree about the slasher though.

 

Like all farm jobs there's a knack to using a 3 point linkage grader; if it wants to go sideways, you are just trfying to take too big a bite with too much of the blade.

 

Watch a good dozer operator at work on new ground and you'll see him only taking half a bite, so the dozer can move smoothly and continuously without stalling or losing traction.

 

The first thing to do is study the lie of the land, and consider the drainage path. If you're new to the area, a neighbour probably knows the water flow.

 

It may be that the strip has a slight downhill slope along it's length, in which case you can crown it and level very slight drains each side and there'll be no drainage issues.

 

On the other hand, if you run the strip across the slope and there are undulations, when you crown the strip up that's going to be the depth of the water dammed up, which will form bogs in an otherwise perfectly good runway. In that case the option is to let the runway undulate by not crowing it (allow the water to flow over it down the hill), or build in underground drains to the low side.

 

Drainage can be more complex than that, but attending to drainage first will prevent the experience poor old Rocketdriver had in his KR2 where what should have been a roll along the grass at the edge of the strip threw him over the nose when the wheels became bogged.

 

In terms of grading it, sure, hiring a grader is best. Normally you'd cut about 150 mm of soil out, then bring in truckloads of drainage rock, then about 100 mm of road base, then gravel,

 

However, you can still do it with a Ferguson and three point linkage grader blade, as long as you can easily change the angle of the blade to cut to the left or right, the top linkage is adjustable, at least one of the arms is adjustable and it has an adjustable height rear swivel wheel.

 

I've always had a rule of thumb that if you can drive over a paddock at 100 km/hr in a car it's going to be OK for an aircraft, and I've graded a track in blacksoil clay with the standard wheel and we went round it in a rally car at about 130 km/hr without much suspension lift.

 

However the standard rear wheel will leave some of the undulations. You can get a much better result by mounting a length of rolled steel channel to the wheel mount bracket, and pinning the wheel to the other end. I wouldn't go much longer than 2 metres with this.

 

The next issue is what type of soil is involved.

 

If it's sand, then as someone said above, you can just cruise along and do a very shallow skim just getting the sticks and stones out of the way.

 

Same with friable soil.

 

If it's clay, or hasn't been ploughed for years and has had cattle on it, it might look smooth, but there will be hard and soft patches, crab holes, and protruding hard lumps of clay. I've tried cutting the high points off with the blade but it's never worked; the blade seems to just move the hard clod along a bit and you never get a smooth ride.

 

This is for people who have never done any grading, or who have had problems with a 3 point linkage grader getting a smooth job.

 

Most people make the mistake of thinking they only have to go over the ground once to finish the job, but it's a bit like cake mix, you need several runs doing different things to get that appearance that looks like a professional road.

 

Firstly, as much as there are minimum widths for surface and runoff for an ALA, go down to your club and measure the smooth surface width - that's what you've become used to.

 

Sight off and peg the strip itself and the runoffs. Even out at the edge of the runoffs there should be no sharp ridges to catch a prop in the case of a runway excursion.

 

My preference would be to shallow plough the strip, but often ploughing pulls out lumps of hard clay which the harrows can't cut through and the paddock is soon as rough as it was before you started.

 

This is a technique of working hard clay with a 3 point linkage grader blade only.

 

The goal here is to cut through the hard clay patches, leaving an undisturbed even base - a lot easier said than done.

 

Next we need to pick a practice area well away from the runway because our mistakes will be there for a long time.

 

Using the top linkage adjuster we extend its length, sloping the top of the blade back and the cutting edge forward; this is the digging mode, the more the angle the more the blade will dig in. It's held at a constant dig level by winding down the trailing wheel.

 

Next the blade angle is set. Anything less than about 50 degrees will see the dirt building in front of the blade and carted up to the end of the strip.

 

A small tractor can't pull a normal width blade through clay, and the blade if often too light anyway, so we have to do what the Dozer operator does and only cut with a small section, which in the toughest clays can be very small.

 

We do this by winding the three point linkage lower arm down so the front end of the angled blade will be doing the cutting.

 

We are now hitting the clay with the pointy end of the blade, which, leaning back wants to dig in.

 

What usually happens in our first test is just that; the blade digs in and either the tractor stalls, pig roots along pulling large lumps of clay to the surface, or spins around like Facthunters did.

 

Those are the lumps and holes you would hit on the strip, so we back off the lower arm a little, maybe wind down the wheel to apply more pressure, and just idle along in first gear, adjusting until we get a steady peel of clay and dirt. This may be 75 mm, or if really hard 25 mm.

 

Once we've stopped the gouging and pig rooting we take a look at the windrow coming of the back end of the blade. We don't want the back end of the blade doing any cutting because there's enough leverage there to spin the tractor around and cut a nice blade long gouge in the strip base. What we are looking for at the back end is for most of the peeled clay to be sliding under the last part of the blade, leaving just a small windrow of graded material.

 

It's well worth spending some time in the practice area getting this just right, then going up to 3rd or 4th gear low range, and trying to get a nice smooth run. If the tractor bogs down because there's too much cut there will be gouges in the base and you might get wheelspin which will make more holes to bounce into once the newly graded surface has compacted down.

 

When you can confidently drive some distance at around 5 km/hr with no pigrooting or bogging, just a nice peel coming off evenly it's time to start the strip.

 

If a tractor tyre goes down a hole, the blade's going to cut deeper, and if the tractor starts to bounce over ruts the blade will duplicate that, so in some case you'll need to slow right down.

 

Next the decision is what the cross section will be:

 

If it doesn't need a crown, I would cut down to the base of the holes in the paddock. Above 100 mm, I'd think about dragging material into the deeper holes first.

 

If the paddock gets soft/boggy in winter then you need a crown.

 

If it does need a crown, then material needs to be cut from the side of the main strip and a rule of thumb might be to cut the strip and runoff areas 100 mm deep then grade all the loose dirt into a crown, so you might have returned an even spread of 100 mm, plus another 50 mm (if the runoff areas were equal to the strip - you'll lose quite a bit just through inefficiency of the small grader). After a few months when the rains have compacted the strip area, you'll have a crown of around 25 mm above the original paddock.

 

If you want a bigger crown, just make the runoff cuts wider, rather than digging the runoff areas deeper.

 

Let's say the forward edge of the blade is on the right hand side (as you are sitting in the seat).

 

For the strip with no crown:

 

You start the cut with the RH blade end just missing your pegged line and run the whole length.

 

At the other end lift the blade out, do a half circle to the right and come back with the RH blade end just missing that peg line, lift the blade out, do a half circle and line up with your blade about half way in from the first furrow (the harder the clay the less width of blade each time.) Better to pull the pegs out at this point rather than grade one under the surface.

 

We're working inwards with the RH tyre on the grass for best traction in front of the cutting end of the blade.

 

Once at the centre you will have a series of shallow longitudinal "V" furrows each with a short side and a long side.

 

Reverse direction, starting from the inside. Line up the cutting end of the blade so it cuts off the peak of the previous furrow and depending where the rear wheel is running you may have to wind it down to prevent digging a deeper trench than your first run..

 

Work outwards and if you get a spade and clear away some of the loose soil you should see an almost smooth, hard base.

 

Call me a comedian you other farmers, but that's the theory. In practise it never gets that precise because the rides get cover in dirt there's play in the linkages etc, but try to finish up

 

with that nice flat hard base free of any ridges, lumps and potholes.

 

If there are still ridges there, wind the wheel down a fraction and go over it again with the aim of hitting the high spots.

 

Next is the dressing.

 

What you'll most likely have is a series of windrows and a stockpile of coil on one side at one end where the blade has dragged it, and another stockpile on the opposite side at the opposite end.

 

Now we just want to dress, not cut or gouge our nice smooth base, so using the top linkage we wind it in to bring the top of the blade forward so the cutting edge is much more upright, or for sand is virtually sloping forward at the top.

 

We want to drag it over the windrows smashing them down, breaking up lumps and trying not to drag the loose soil to the end of the strip.

 

We might pull the lower arm up to reduce some of the tilt since the tractor can now pull the whole blade through the soft soil, but we want all the soil to be released from under the blade rather than form a windrow at it's trailing end which we then have to deal with again.

 

We start in the reverse direction to the first cut so we drag the stockpiles away from the end of the strip, and this time, if the blade is still holding soil as we approach the end of the strip we minutely lift the linkage with the hydraulics to let it dribble out over the last 20 metres or so. This is a rewarding skill, like a good landing.

 

At this point we can bust the clods down with harrows, otherwise angle the blade forward more until it just scrapes over the surface and go over it until we get it smooth.

 

 

[Gentreau]

Think people misunderstood my post... I was trying to describe what a grader looks like to somone who asked a question about them.

That would be me, thanks for the pics Boingk, I know who to go and talk to now.

 

Turboplanner, thanks for the step-by-step, much appreciated even if it only means I'll understand a little of what the grader driver is doing .....

 

 

[biggles5128]

Turboplanner, very detailed and spot on, appreciate your efforts there. I will be using a grader as opposed to a tractor which should give me a better result. Same principle applies though. The soil is basalt and the strip is level across the strip, there is a fall of about 2 degree from west to east down the length, so thinking that I should not have much of a drainage problem. Even after significant rains I can drive the Toyota or the quad along this area without sinking or even leaving ruts.

 

I am getting excited at the prospect of finally getting this project underway.

 

 

[boingk]

You going to tack a hangar on as well mate? Gotta have a hangar... maybe even a fuel depot?? You know those woolies vouchers are good for 120L at a time...

 

- boingk

 

 

[Camel]

Biggles, How long is your strip and are you going to have a cross strip? I am in the process of building a strip, it is level ground and flood proned and I have been slashing it for months as it was in a real bad state for several years due to no slashing and wet weather and no cattle on it, grass was real high. I have only owned the property for a few months and bought it with the airstrip in mind, I have not landed there yet but it is getting close. I was in the earthmoving game and sold my machines before and wish I had it now.

 

 

[dazza 38]

You going to tack a hangar on as well mate? Gotta have a hangar... maybe even a fuel depot?? You know those woolies vouchers are good for 120L at a time...- boingk

Could be more than 120 litres, is for diesel not sure about unleaded . I always put in over a 120 litres at a time in my Patrol. Got just over $16 back two weeks ago when I fueled up.It was a 10 cent discount per litre that time instead of the normal 4 cents a litre for some reason. Put in 160 litres of diesel at a Woolworths Caltex .

 

 

[J170 Owner]

Years ago I watched a video on how graders use laser beams, GPS and white man magic to grade roads, runways etc to within tens of millimeter accuracy. Fascinating stuff. Farmers use the same technology when working their fields.

 

 

[biggles5128]

The strip length will be 600mtrs and no cross strip, the winds favour east west as will be the orientation of the strip. And oh yes there will be a hangar, might even have my swag in there just in case the house door is locked when I venture back inside after hours of pondering and tinkering as a bloke does in his shed. No only joking the bride shares my passion, as least that's what I think....

 

 

[boingk]

Dazza - they're offering 10c/L if you spend over $100 at Woollies, excluding liquor.

 

Biggles - sounds bloody good mate! Hope to do this myself but in all honesty will probably stay at Goulburn airport. The fuel I'd spend going out to the farm and back would probably almost equal a weeks rent at the hangar... so may as well stay there.

 

Cheers - boingk

 

 

[biggles5128]

Finally got the strip done, sprayed out the area, put the grader to work then rolled the strip. Using an air seeder we planted Fescue and fertiliser then dragged mesh behind the bike to break up the small clods then a final roll. The rains came the next day so all good. Just have to wait for it to grow now while I ponder the hangar.

 

 

 

 

[Gentreau]

That looks great, what's the difference in level between the crown and the sides ?

 

 

[Pilot Pete]

Great pics......dogs look great:cheezy grin:

 

 

[flyhi]

Looking good Biggs

 

 

[Kyle Communications]

That grader would look real fine at my farm....could do a lot of wondrous jobs with that

 

 

[Blueadventures]

Hi Looks great. What they do at an established grass airstrip up my way is when its a bit rough we tow two steel rings joined up and down the strip. The rings are each about 2 meters in diameter of 10mm thickness by 125mm high and as you tow them they stay flat / horiziontal and the front edge acts like a scraper and the back part of the ring settles the dirt. Its surprising how flat and smooth it makes the surface.

 

Cheers

 

Mike

 

 

[Guest Howard Hughes]

Finally got the strip done,[ATTACH=full]20743[/ATTACH]

Great looking strip, will it be open to other rec flyers?

 

 

[Kyle Communications]

Blue

 

Are the rings one behind each other or are they side by side. I have been using a spreader bar I made and tow behind the tractor on chains about 6metres behind but even at 200 plus kg it is a bit light it bounces a fair bit. if it has rained and the ground is moist then it works sort of ok but takes quite a few passes I need to put a couple of 44gal drums with water on top I think

 

 

 

 

[biggles5128]

There is no real crown as such in the strip just a very subtle spoon drain on the sides which was a result of the skim off the top from the grader. My only concern with others operating out of here would be potential litigation, so will be looking into that.

 

7 days after seeding and I have green shoots already so starting to take shape.

 

 

[flyhi]

biggles5128

 

You will soon need to mow it at this rate. I use an old Howard Rolmow72 on mine. Cuts fairly short and rolls with 450kg keeps it fairly smooth.

 

flyhi

 

 

 

[Guest nunans]

Biggles, how long did the grader spend working on the strip? It looks like it was fairly even and level to begin with.

 

Nice job though, all the right gear makes a difference.