Colorado_Carter Teardrop Build

[Colorado_Carter]

Thanks Sharon!

[KCStudly]

KISS-keep it simple stupid. I need to get that tattooed somewhere.
...
A stick would have been sooo much easier.

Amen, brother! "Missed it by that much." - Maxwell Smart.

I've just worked my contingency plan through for gas struts six ways from Sunday (so to speak) using 3D CAD modeling and I can tell you that it is one of the most complex things to wrap your brain around, even with the advantage of these design tools. I'm still not sure that it will all workout in the end.

Here's a suggestion. Since your hatch and galley are already built and installed it may take a little transferring of points or making a mock-up piece to represent your hatch side due to lack of access to the inside when the hatch is closed, but I hope it can help you figure a solution. First pick which anchor point you want to leave put. Make up a "story pole" (a gauge stick) that has three holes in a row: one for the pivot point you do not want to change; one that represents the center to center (C/C) of your strut when it is just a little bit shy of being closed all of the way (allow maybe 1/8 to 3/16 inch longer than the collapsed length); and the third hole representing the extended C/C of your strut. Now prop your hatch up to where you want it to be in the raised position, put the story pole on the pivot point that is staying put and strike an arc with a pencil in the long hole on to the other side (hatch or wall, depending). Transfer or mock up a gauge piece that will show you where the known pivot point is in the closed position; then strike another arc through the short hole position using this as your fixed center point. Where the two arcs cross is a pretty good place to put the center of the pivot point that needs to be moved.

When the hatch is closed it would be good if the imaginary line passing through the long axis of the strut is aimed at or near the hatch hinge centerline. Since your farthest strut pivot point relative to the hinge anchors to your hatch, you can get a little positive closure by aiming your strut just slightly above the hinge a couple of degrees. (If your farthest strut pivot point had been anchored to your wall, then you could get a little positive closure by aiming your strut just slightly below the hinge a couple of degrees when the hatch is closed.)

Hope this helps. Clear as mud?

[Colorado_Carter]

Thanks KC!

I printed that to to take home and try.

Let you know how it goes on Monday

Doug

[Junkboy999]

Doug

Let me know if you what my old rack handle my TD came with for a hatch support. I’ll mail it to you.
( see my second post on page three of this thread for reference. )

Just Kidding. My little woody has two extra holes in it from trying to get the supports installed with the
hatch being previously cover. I do have to say that just fix supports might have one advantage over gas
struts. I drove back from Bikes Babes and Barbeque, oops I meant Bikes Blues and BBQ, last year and forgot
to secure my TD hatch. Just the weight of it was enough to keep me from losing half my camping gear.

[aggie79]

I've just worked my contingency plan through for gas struts six ways from Sunday (so to speak) using 3D CAD modeling and I can tell you that it is one of the most complex things to wrap your brain around, even with the advantage of these design tools. I'm still not sure that it will all workout in the end.

Here's a suggestion. Since your hatch and galley are already built and installed it may take a little transferring of points or making a mock-up piece to represent your hatch side due to lack of access to the inside when the hatch is closed, but I hope it can help you figure a solution.

KC is on the right track. I did my trial and error in pencil on the sidewall and only made one "extra" drill hole on my strut mounts. I'm not good with math, don't know CAD, can't draw, and can't engineer my way out of a corner. Fortunately, I was taught some old school methods on how to lay out curves, find midpoints, etc. Following is a way to lay out graphically the strut bracket locations fairly close if not right on the money. Hopefully I can do a halfway decent job explaining this.

You need to have your trailer level and at the height it will be with wheels and tires on. If it's not there, you'll need to place blocking, jacks, etc. to that height. Next, prop open your hatch to the height you want it to be in the raised position. Next, pick a lower mounting point for your strut. (Be sure to account for the thickness of your hatch to be sure that the bracket and strut will clear the hatch thickness in the closed position.) I'd start with the lower mounting point you already have. Measure and transfer the pivot location of the lower mounting point/strut to the outside of your sidewall and place a "+" to mark the spot.

For the next few steps you can either use the strut without the lower bracket attached but with the upper bracket attached or replicate it with a tape measure for the strut length and a cardboard spacer for the upper bracket with the upper pivot point drawn on it. Center the lower pivot point of the strut over the "+" mark you made, and pivot the strut and upper bracket to the location where it would be on the bottom on the hatch. Temporarily tape this in place if possible. Measure the distance from the outer edge of the hatch to the upper pivot point of the strut. For discussion, we'll use a 2" hatch thickness and 1" bracket depth, for a total distance of three inches.

Now measure the distance from the pivot point of your hatch - the hurricane hinge if you're using one - to the upper pivot point of the strut (with the hatch in the desired raised position.) Using this distance, and with hatch pivot point as your radius point, swing the tape measure down to the sidewall. Draw an arc on the sidewall about 4-5 inches long. Then, on the arc, measure in the 3" distance from above and mark a second "+" at that spot.

Finally, measure the distance between the two "+" marks. That would be the compressed or closed length of the strut assembly. By assembly, I mean the compressed length of the strut plus the added distances to the pivot points of any fittings added to the strut. If the measured distance between the two "+" marks is greater than the actual length between the compressed strut pivot points, it means that this trial location of the brackets and strut position works - at least it does geometrically. On my teardrop, I can't remember exactly, but I believe I added 3/4" to the actual length to give myself some wiggle room.

If the measured distance is less than the actual distance, the hatch won't close and you'll need to reposition the brackets, and run this exercise again. With the strut orientation as you have (as do I), to keep the same hatch raised position, you'll need to move the lower bracket further inboard and the upper bracket further outboard.

While you're at it, you can draw a line between the two "+" marks. The area from the line up has to be unobstructed and can't intefere with upper or lower cabinets or countertop or your hatch won't close.



This really is much easier than how I described it. Hopefully I haven't added to the confusion.

Take care,
Tom

[KCStudly]

A question for Tom regarding the positive closing forces. How much over travel (or over center) do you recommend to get the positive hatch closure effect? I've been thinking that 2 or 3 degrees should be enough, but had also considered that compressing the hatch seal might come into play so maybe a little more would be needed(?).

Or am I over thinking this. With the strut compressed in a straight-ish line to the hatch hinge does it really have enough leverage to do any lifting or closing at all? One more question, how much work has to be done to get a hatch started opening before the struts get a big enough angle going (leverage) to start helping?

The reason I ask is that sometimes my wife has a hard time even breaking the seal and opening the hatch on my TV (Ford Escape), especially with just one arm, such as when carrying items to put in the back. Just wondering if more of a positive start angle would be better (i.e. strut aiming away from the hinge centerline trying to open hatch a bit). Not enough so that the hatch opens itself when unlatched, but so that there is more of a balance and some force helping to do the initial lifting.

I guess it is different for everyone. My hatch is more Benroy like; kind of flat and short on top, but tall and steep at the rear (CG closer to hinge); whereas your more traditional TD shape has a longer flatter curve with some weight concentrated at the sill end due to the bottom curl being further away from the hinge (and the CG further away, too).

(Note: this is not technically a highjack because it is still on the topic. )

[Colorado_Carter]

Finally Progress.....I almost just started putting on the aluminum skin, but thin thought I should fill the holes and seams then add a couple coats of primer. I've spent too much time and effort to skimp on sealing it correctly. It's all pretty and white.

I spent quite a bit of time "fine tuning" the hatch this weekend. The sides needed trimed, a groove made for some trim and weatherstripping, grooves for the slam latches, and yes dealing with the struts. The struts...... are beyond me, apparently two degrees is insufficient. I played around with them quite awhile, adjusting the brackets a couple times I finally manged to get it to close. Unfortunatly only those under 4' can comfortabley use it. I will try again though, using all of your advice. Thank all for your input and help.

[KCStudly]

Well darn on the struts, but at least she is looking mighty fine!

[aggie79]

Well darn on the struts, but at least she is looking mighty fine!

I agree! Your teardrop looks fantastic. Don't let the struts thing get you down. I have been "finished" with my teardrop for about two years (after a three-year build) and I still have things I need to fix or do on it.

[Colorado_Carter]

Thanks for the positive remarks, I appreciate them.

[Heifer Boy]

I like your 'Big Fat Fun' poster in the background. Very jealous of that one...

[Colorado_Carter]

No pics this week, I refuse until the aluminum skin is farther done and looks pretty. I installed two the three top sections, they came out pretty well i think. I should consider an extra pair of hands for the next effort. It would just make that process easier.

I did figure out how to install the struts, they work great. there is more than one way to skin a triangle.

[KCStudly]

I did figure out how to install the struts, they work great. there is more than one way to skin a triangle.

Oh good. I am looking forward to hearing about your solution, as well as seeing your other progress.

Great milestones!

[Colorado_Carter]

Finally an update!

Its been busy at work, and progress on the project was slow. Until this weekend-finally two days of beautiful 70 degree weather and no other responsibilities. I have managed to get most of the teardrop skinned (except the hatch). That was a chore, I didn't initially think it was that big of a deal or would take very long. I wasn't satisfied with the result unitl I got the sides and trim on. I think a little polishing to get some of the minor scratches and scuff marks off and it will look great.

I am looking forward to getting the door, window and fan installed.

[asianflava]

He he those struts was probably the trickiest part of my build. I tried several different locations and it would either not close, not hold it up, or not open wide enough. I took a tip from another builder to find out what was going on. Turn on the camera's self timer and take a picture of the inside of the hatch with it closed. Turned out that the struts were hitting one of the shelves. Even now it's a trade off, doesn't open quite wide enough and it will barely hold it up. I think of it as more of a lift assist.

Trailer is looking good!