Roof height with 36" struts?

[philos65]

I'm about to start sewing my vinyl sideliner with windows. Unfortunately I'm in California and the 80s Keystone is in Wyoming.

Has anyone measured how much the roof raises when the 36" struts are fully extended. The struts I got are 20 and a half inches fully retracted. I'll be sizing the sideliner to match the fully extended struts, or just slightly less than full extension.

I don't need it to the 32nd of an inch, but within a half inch or inch is enough will help me size and place the windows.

As an aside, the sideliner width (vertical) is 30 and a half inches. The original sideliner, shown in the attached photo, was 25".

Thanks...

Jeff

 

[shellback]

I rebuilt a 79 Grandby and I have about 6' 1" headroom inside the camper. I think my lift panels are about 26 inches high. I used 36" 40# struts. I'm guessing I started the top of my windows about 7"s down from the top. I could get you a measurement tomorrow. I bought 60" fabric and cut it in half for a 30" panel. I used the factory cut edge as the top and worked down from there. You install the side liner to the roof first, then raise the roof to finish height. The extra of the 30"s stretches over the camper body and then you pull it tight and screw the trim down. Then cut the extra off with a razor knife.

 

[philos65]

I'd appreciate knowing how far the struts extend and how high your roof is relative to the camper body. Thanks for measuring!

Jeff

 

[Argonaut20]

This is basically a right triangle problem. When the roof is collapsed, the horizontal distance between the ends of the struts has to be more than the collapsed length of your strut. Otherwise, the roof can't compress the strut enough to settle onto the camper. If your struts collapsed length is 20" and the length fully extended is 36", the max height will be the square root of 36 squared minus 20 squared or square root of 896 which is a bit shy of 30". Actually, you are going to be less than 30" by an inch or more because there has to be some tolerance built in. This won't be the height of the vinyl because the mounts for the struts are on the metal of the camper and the metal lip of the roof.

 

[shellback]

I'd appreciate knowing how far the struts extend and how high your roof is relative to the camper body. Thanks for measuring!

Jeff

Okay, these are my measurements, others could vary I'm sure. My rear struts are extended 35.5 inches. The mounting balls are 50 inches apart at the top, and 7.5 inches apart at the bottom.I used right angle ball brackets, with the ball at the top. The top ball is actually about .5 inches above the roof. This was done to take advantage of trim screw holes to mount the bracket. My brackets had 3 mounting holes. I first used just the center hole, and then was able to move the bracket either right or left about .5 inches if I needed adjustment. In other words, if I collapsed the roof, and the struts still held the roof up, I could move each brackets about .5 inches closer together so the roof would fully close. On the inside of my camper, I have 75 inches of head room. Measuring from the roof to the camper body, the fabric is 25.5 inches. My window starts about 6 inches down from the top. So when you make your fabric panels, leave at least 7.5 inches above the window. My camper had the fabric sandwiched between the trim and the roof. When I rebuilt it, I unstapled the roof skin, and tucked the fabric between the roof framing and roof skin, and then installed the trim. Keep in mind, I installed my struts after the camper fabric sides were installed and trimmed, as I made factory style lift panels.

 

[Wallowa]

Ignorance on my part...but don't the supporting folding end panels determine the height of the roof [length of side material] and not the struts? The struts never go vertical?

 

[shellback]

Ignorance on my part...but don't the supporting folding end panels determine the height of the roof [length of side material] and not the struts? The struts never go vertical?

The OP is doesn't want to use lift panels. He intends to use the struts to hold up his roof, and then maybe use some bracing. I used factory style panels, and my fabric was determined by the panels. I think he just wants to get an idea how high his fabric will have to be using struts.

 

[Wallowa]

The OP is doesn't want to use lift panels. He intends to use the struts to hold up his roof, and then maybe use some bracing. I used factory style panels, and my fabric was determined by the panels. I think he just wants to get an idea how high his fabric will have to be using struts.

I missed that he wanted to hold the roof up by the struts alone [no end panels] with a possibility of other supports...my Hawk has a max roof load of 1,000 lbs [snow etc] can't grasp how he intends to support the raised roof relying to some degree on struts...my understanding is that struts offer some support/assist when raising and lowering roof and never go vertical...will be interesting to see photos of finalized roof support with I assume internal supports other than struts...definitely beyond my abilities to fabricate!

Thanks for info...Phil

 

[philos65]

Thanks for the math memory Argonaut20, and the measurements Shellback. I have enough now to place the windows. My concern is that the campers I've sat in have the windows way too high - all you can see when sitting down is sky. I want to be able to see the actual horizon when sitting. The three windows around the cab over bed can be higher - for a bit of privacy.

Wallowa - my thought is that the struts will hold up the roof, stretching the fabric taut. If that works, I'll likely install vertical braces in the inside corners somehow - nowhere near that point. If it doesn't work, I'll just install emt lifters.

Thanks for the replies!!!

Jeff

 

[Wallowa]

Thanks for the math memory Argonaut20, and the measurements Shellback. I have enough now to place the windows. My concern is that the campers I've sat in have the windows way too high - all you can see when sitting down is sky. I want to be able to see the actual horizon when sitting. The three windows around the cab over bed can be higher - for a bit of privacy.

Wallowa - my thought is that the struts will hold up the roof, stretching the fabric taut. If that works, I'll likely install vertical braces in the inside corners somehow - nowhere near that point. If it doesn't work, I'll just install emt lifters.

Thanks for the replies!!!

Jeff

Thanks Jeff that explains what I was missing..just an FYI..without pushing my end panels into a vertical position my 4 struts[40lbs each?] will not hold the top and side material up...if I don't lock in the end panels the top will slowing sink back down against the resistance of the struts..I do have the 160w FWC Zamp roof solar panel and two Fantastic fans that add roof weight.

Wish you the best in you venture and please let us know how it turns out..

Phil

 

[philos65]

I've got 60 and 40 lb struts and I'll try those out to see what works. I'll look for the "slowing sink" of the struts - if they work hold the roof up initially, I can install some vertical braces once it's up.l My roof will have two 245 watt, 40 pound panels plus two fantastic fans and the roof frame I built. The roof is 65 pounds or so. I figured 180 pounds or so to lift and hold. There's another discussion around this here.

http://www.wanderthewest.com/forum/topic/15790-struts-to-lift-roof-and-no-lift-panels-or-emt-lifters/

I'll post pictures of what happens!

Jeff...