Mechanical Linkage

Please clarify: is the "window" and "roof" the same thing in the above description?

The best software for this sort of thing is graficalc

It's not outrageously expensive, but I don't think you'd want to buy it for this single task.

Not sure if you can get a trial version.

I would use table top lift support hinges and just angle the mounting position so the top is in the desired position when open....

$20...

This wouldnt work for me Solareagle. With the roof down (on the right) the open side is only 90cm (3ft) high. I need the roof to lift and pivot to give me access to the installations.

That's why you would mount them at an angle...yes maybe a little unorthodox, but should work...the hinge wouldn't be closing completely...mount the hinge to the roof, hold it in the open position you desire, take note of the mounting location for the hinge bottom, place some supports to hold the roof in open position and mount the lower hinge....might need some tweaking...

Soss Hinges might have an off-the-shelf solution for this.

Alternatively, you could experiment with a few popsicle sticks and thumb tacks.

Yes, that had occured to me too......I was looking for a more "engineering " solution though!

There are sliding skylight mechanisms, as shown (if you have the roof space). Surely you are not crawling in through the skylight. There must be a door to the pumphouse. Do you want to open the skylight just so you can stand up straight?

The pump house is essenially a lean-too. The entry is on the right and is (roof down) only 90cm (3ft) high. Sliding the roof foreward and then hinging could be a solution. One I hadn't considered so far. Thank you

I would use 2 gas springs.Here is a link that may help you calculate the specs for your needs.

https://www.dictator.nl/Downloads/EN/Reg.6/614-E-Selecting_and_Calculating_Gas_Springs.pdf

Nice link, thanks. A simple link won't do. I cannot hinge this at the far left edge, I have to either lift and tilt or slide and tilt.

15kg? Just lift it off.

Thats my current M.O. The corrugated plastic roofing will get damaged though. It is also rather inconvenient as it is 1m50 wide

Get your wife or girl friend to help :)

Did you, perchance, read the original question?

I think you need to go with the KISS principle. Forget the program and just use the bonnet hinges as you identified in your text as having the desired configuration.

Sure you may have to trial and error it but by the time you get a program, familiarise yourself with it and then draw the plan you can have it in and working.

I think this may be the answer, print a scale drawing and use some links made from card to get the suitable distances and anchor points and then rescale up.

If you want simple,measure the maximum allowed opening height from the top to the ground.

Use a piece of dowel cut to that length.Attach it to the underside of the roof with a hinge so that when the lid is open,the dowel will drop down,holding the lid in that position.

To close, simply lift the roof,hold up the dowel as you lower the roof.

The next time you open the roof,the dowel will drop down automatically.

Hitekrednek, holding it up is not the problem. It is essentially the same as a car bonnet inasmuch as it is not possible to hinge this on the top edge.

You had the answer the whole time.

Go to a recycler and buy a set of car bonnet hinges with springs.

They should be very cheap.

Trial and error the mounting position to get the best results.

Alternatively,mount the hinges on the outboard side so there is no interference from the window above.

Web search "hinges for UPVC windows".

Copy the link lengths and scale to suit.

Or grab a set from a junk car.

https://youtu.be/jc057w0qTNQ

Would it be possible to use "swing clear hinges" as used on hospital doors?