MDPE hoop size??

[Crazysprout]

HI Guys,

right I need a advice on hoop size? im building a diy poly tunnel. I have a 10ft wide bed which the hoop needs to cross. I plan to have 3ft straight sides before the hoop goes over to the other side. soooooooo the big question is how long does the MDPE pipe need to be cut? I sure someone will just work it out quickly, but I cant get my head round it. don't want to waste it by cutting it to short. lol

[coveredinoil]

22feet (21.7 if you want to be more accurate)


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[Crazysprout]

I just knew there would be someone who could work it out! Thank you!

[RedThorn]

3ft+3ft for verticals =6ft

Half circle is as follows

22/7 x 10/2( pi x d/2)
=220/14
=15.71428571428571

Add two together
=6+15.71428571428571
=21.7ft then convert decimal places to inches
Near as beep 21ft 8,5inches

[Olorin2001]

I want to know how your going to get the pipe to go from the three foot sraight sides into a curve then back to a straight side again?
I would expect it to form an eclipse.

[RedThorn]

Stakes driven into the ground that protrude 3ft is One way.....

[Bigmallly]

Be aware when using longer lengths that they can sort of bend in & out, I had a begger of a job when I made the walk in Brassica cage & my hoops were only 13 foot.

[Crazysprout]

I make the straight sides I have treated broom handles. These fit perfectly into the 32mm MDPE pipe. Then these fit straight into 7ft scaffold poles I have put 4ft into the ground already. Thanks you the input guys much appreciated. :-)

[Olorin2001]

don't forget to use heat tape on all the pole and pipes

[gardening_gal]

Is it the done thing to bump an old thread or should I have started a new one?

Anyway, I have the same question as the OP. Only I don't understand the answer they got.

How do I work out how much pipe to cut? I have a little plastic raised bed. It's only 50cm across by 100cm long. I want to put strawberries in it and put a couple of hoops over it, with mesh on, to keep the neighbour cats out and also the birds.

It doesn't need to be high, the bed is 25cm deep so part of the pipe would be stuck down that much inside the bed. I'm thinking maybe 2 foot high? Does that sound right? Wrong? Is that tall enough to cover strawbs?

RedThorn explained the workings earlier in the thread but I don't understand where the 22/7 and the 10/2 bit came from so I have no idea how to use those workings but with my figures.

[Lardman]

For the example to work the dome height can't be more than the bed width. The dome height starts after the vertical sections.

In your example.

Bed width :50cm
Dome height 50cm
Vertical height 20cm

Circumference = 314cm
Dome plastic (314/2) = 157cm
Verticals : 20x2 = 40cm
Total = 157+40 = 197cm

I'd add another 4" to that so the dome starts 4" above the bed. 197 + 20 = 217cm

If someone would like to check my maths

[Cadalot]

Normally I put a link to a posting on my blog where I explain how to work this out will illustrations but since having my wrist slapped for doing so I no longer do that kind of thing

[gardening_gal]

Normally I put a link to a posting on my blog where I explain how to work this out will illustrations but since having my wrist slapped for doing so I no longer do that kind of thing

With illustrations. Now you are talking my language.

[gardening_gal]

For the example to work the dome height can't be more than the bed width. The dome height starts after the vertical sections.

In your example.

Bed width :50cm
Dome height 50cm
Vertical height 20cm

Circumference = 314cm
Dome plastic (314/2) = 157cm
Verticals : 20x2 = 40cm
Total = 157+40 = 197cm

I'd add another 4" to that so the dome starts 4" above the bed. 197 + 20 = 217cm

If someone would like to check my maths

Thanks for taking the time Lardman, really appreciated.

[gardening_gal]

For the example to work the dome height can't be more than the bed width. The dome height starts after the vertical sections.

In your example.

Bed width :50cm
Dome height 50cm
Vertical height 20cm

Circumference = 314cm
Dome plastic (314/2) = 157cm
Verticals : 20x2 = 40cm
Total = 157+40 = 197cm

I'd add another 4" to that so the dome starts 4" above the bed. 197 + 20 = 217cm

If someone would like to check my maths

Still confused.

If the bed width is 50cm and you times that by 3.14 to find the circumference, that would be 157. But that is for the whole circle? Not just the top arc bit that I need? So would it not be 157 halved?

So 78.5 plus 20 + 20 for verticals = 118.5.

I hated maths at school, I was very bad at it.