danlott wrote:DWT77 wrote:Since my teardrop is 5' tall my hatch came out to be 65" and 100 lbs for the dead weight. Spreadsheet said I needed 39" springs at 162 lbs of force each (Total 324 lbs). I was able to find 36" springs at 160 lbs so I gave them a shot. (I may have used the mounting locations from the 39" the spreadsheet recommended I don't remember if I converted the numbers or not)

Sorry you are having problems. I do have a few questions?

Looking at your pictures I would think that your attachment points are not correct for the stroke length of your struts. Also the force of the struts looks like it is too high.

What is the stroke length of your struts? What is the distance of the attachment points from your hinge point? Also is the length of your hatch a straight line from your hinge point to the bottom of your hatch or is it the length along the curved surface?

Dan Lott

Dan I took some pictures and will try to be detailed so hopefully we can find out where I went wrong.

You mentioned stroke length that got me to thinking about the spreadsheet. I'll get back to that in a minute but first here are my measurements for the hatch

Also is the length of your hatch a straight line from your hinge point to the bottom of your hatch or is it the length along the curved surface?I took the measurement in a straight line.

I tried to do the dead weight again because now I want to re-check everything but with the hinge not secure now I was having an issue with it and not sure if the weight I was getting was correct.

So for now lets stay with the 100 lb dead weight (I will double check when I get the hinge back on)

So on to the spreadsheet. When I filled out the spread sheet I used the above numbers. It came back with this

I couldn't find 39" but I did find 36"

I ordered these gas springs

https://www.amazon.com/gp/product/B007M ... UTF8&psc=1Extended Length: 35.43" (900mm) (center to center of ball socket ends)

Compressed Length: 19.29" (490mm)

Stroke Length: 35.43 - 19.29 = 16.14"

Force: 80 lbs (356 N) (Total = 160 lbs)

End Fittings: 10mm nylon ball sockets

I made the distance of the bracket attachment point to the hinge point as close to 13.72" as possible

I had the hinge secured and screwed in. Then I measured on the outside of the hatch rib 13.72" Then I marked it with a pencil (this was before I had everything painted) Then I transcribed that on the inside of the gusset using a square. I took some pictures just now for reference.

Then transcribed it to the interior side of the gusstet

I got the gas struts from above installed and the hatch would not stay up. As soon as I let go it fell.

So I was like well maybe I am just off a little bit either on measurements or something so I tried these struts. Which are 90 lbs instead of 80 lbs

https://www.liftsupportsdepot.com/lift- ... t-support/Extended Length: 36.00

Stroke C [in]: 15.20

Compressed Length B [in]: 20.75

Force (Lbs): 90

The same thing happened. The hatch just fell when I let go of it.

Now I am thinking ok I did something wrong.

I went back to the spreadsheet read it again and looked it over.

I changed the number of springs to be used to 1

The required force in gas springs changed to 312 lbs of force

I was like oh ok the spreadsheet is for each gas spring needs to be the 162 lbs not a total. Which this made sense because even at 2 springs @ 90 lbs each (Total 180 lbs) my hatch still wouldn't stay open

So then I bought these gas springs

(Which were the ones installed when the hinge failed)https://www.liftsupportsdepot.com/lift- ... t-support/Extended Length: 36.00

Stroke C [in]: 15.20

Compressed Length B [in]: 20.00

Force (Lbs): 150

Which is a total of 300 lbs and is not as much as the 324 lbs the spreadsheet said I needed. (So I think anyways if I did everything correctly)

With all of that said it brings me back to the stroke length you asked about.

The original stroke length on the first set of gas springs was 16.14"

The ones for the last gas springs that failed were 15.20"

I never entered the 15.20" back into the spreadsheet to change the bracket attachment points. (I did change the bracket position a little after they broke loose the first time so not to use the same screw holes)

That is right at 1" bracket mounting difference.

Did I input all of the numbers correctly?

Did I interpret the spreadsheet correctly?

I hope all of that made sense. Please let me know if I need to clear anything up.

Thanks for the reply and the help!!