The minium area you should be looking for would be a carpark size of 30+ cars minium, open with very few trees to block the wind, minimal fences and other things to hit. You need to think of onlookers and their safety as well.
The harder the surface the faster you will go, soft footy ovals are a good size but often quite soft, I often work on the thoughts for sand and mud is if you leave a "full" footprint on the surface it will be to soft for sailing.
Safety gear that should be regarded and used EVERY TIME should be, closed footware, helmet, seatbelt and optional leather / gardening type gloves.

Mark, just got your email.

I will post a pair of bushes tomorrow morning- so you should have them in a couple of days.
("Terrain Tamer" part number 90385-18022P)

The dimensions are as follows-

40.20mm outside diameter,
18.20mm inside diameter,

While you are waiting for the Aussie Post camel train to deliver, you can find your steel tube and steering shaft with the dimensions shown here.

You will need a piece of tube AT LEAST 90mm to 100mm long, with an internal diameter of 40mm.

It might need to be a bit longer depending on the diameter of your main chassis tube. (I think I cut mine at 120mm)

Your steering shaft will need to be of 18mm (or a smidgen larger)
if you wanted to get really flash, you could fit a grease nipple at the half way point of the tube so you can pump grease into the steering head- but that is not mandatory!

As far as safety gear goes- helmet, goggles or sunnies, shoes or boots, seatbelt are needed- and the main thing to remember if things go pear shaped is DONT PUT YOUR FEET OUT OF THE CART!!! its not a good idea to put your feet on the ground if you are moving no matter what the speed!

its easy to forget- and you can guarantee that kids will forget it real quick too!

I am thinking of fitting straps to the pedals so the kids cannot remove thier feet until I unbuckle them.....

dont worry about the cost of the bushes- stick some construction photos on the forum if you can and we will call it quits

Your 4m sail should be ok if you are on a hard surface like salt, clay, concrete or bitumen.

If you are trying a soft surface like a well cared for grass oval you probably wont move much...however if it is a drought affected oval that is a bit dried out it might work.

As for the battens- I am not an expert in that area so its best to speak to someone who realy knows what they are talking about, some sails not only need battens- they need the correct stiffness batten too!

posted the bushes this morning, the steering shaft can be made from a long bolt of the corect diameter, or if you have access to a lathe- or someone who has one, you can turn one down fron steel barstock.

If you know any kids in high school they can probably do the job for you as the manual arts section has all the machinery there.

If there are any recycling centers in your area visit them regularly to find yourself cheap secondhand sails.

You are right,head into the wind to de-power same as water sailing.
THe brake is used after you have slowed down and ONLY in the last few metres to come to a stop.

Whoooo hooooo bushes arrived today!!!! Thanks sn these are full on bushes, i wont feel a thing from the steering!!! Started welding on the w/e. Not the best weld ever but they should hold. i am going to continue building this one as i am anxious to sail!!! I will more than likely build another one taking more time to get the welds looking good. I have not welded for a couple of year so i should have practiced more!!!! Fortunately i already have half the materials for my next one. Also I have ordered the fallshaw wheels hopefully they will arrive late this week. $60 delivered per wheel. can anyone tell me how & what is seating the bearings on the axel? Should i be using a 20mm washer to hold wheel straight or is that what the seating does? i am a little confussed
cheers
gt

Thanks Hiko, starting to make sense. I think I will use a washer (neater) can i use the washer on the rear as well.
cheers
gt

thanks hiko, its about time for a browser update...its 2010. cant wait to get my wheels then it will all make sense {i hope}.

Thanks for asking & sorry for not keeping people up to date I will post some pic this w/e. Its nearly finished, not 100% happy with front end something is slightly out, however pushes around well & steers straight. Only seat needed to be finished & then wind. i hopefully can test it at the local train station carpark sunday arvo. Been watching and usually empty at that time. I also think my sail may come down too low. could i just get a longer mast? or will i need to cut & sew the sail.
cheers
gt

There is always a simple solution,
Thanks for that aus
I am getting excited now hope it gets windy!!!!

i will scrounge one i think, dont want to give the misses any excuss not to vacuum
i was going to use a wood pole but a vacuum extension is a work of genius. Would a plastic extension be strong enough or should i go metal?
Cheers
gt

You could put some wood inside the plastic tube perhaps if thats all you can find
A hose clamp around it could make the height adjustable until you find the height you want
We would love some pictures we love success!
Cheers Hiko