I have started work on the design of my Tear Drop

[davefullmer]

Hello everyone.

I have been looking over several peoples teardrops and have settled into one that I think would be really nice to own and would give my wife and I a place to sleep when we go to Michigan to the family camp out reunion every year.

While looking at the profile sticky, when I first saw 48Rob's Cabin Car, it immediately caught my attention. That design looks elegant and very 1940 and 50ish. A picture of Rob's Cabin Car is here:



I contacted Rob and did a little research on the originals and although I don't plan on building an exact copy of either the original or Rob's, I think mine will be close. Besides, who is going to know the difference?

My first task is to play with CAD and work out some details with the frame, space and misc. Since there are no plans available, I will have to draw the plans myself. All I have to work with is the pictures of Rob's and of an original.

My first attempt is the profile:


I am working on the frame now. Rob is also suggesting a dropped floor section in the cabin.

I will keep adding to this thread as I progress.

Dave

[mikeschn]

Looks like you're off to a good start. :-)

Mike...

[davefullmer]

Here is my frame drawing so far.

Note the frame work for a drop down section in the cabin.



Dave

[angib]

Dave, there are a set of basic Cabin Car drawings on my web site (click on 'Design Library' menu item).



I decided the front top shape of the Cabin Car does not match any simple geometric shape and it has to be drawn either 'by hand' (as no doubt it was originally) or as a bezier curve.

Andrew

[davefullmer]

Thanks Andrew,

I did see your's in the Design Library but since I didn't have the dimensions, I had to go with my own.

I want to keep it fairly light, but my wife and I are too old to be cramped when we get up and also find that getting up from ground level in a tent or a small tear is just too difficult, so we want some room. I don't mind having something larger because we won't be going back in the boonies or up any steep mountains.

Actually, I feel that something about 1500 pounds or less that would not be higher or wider than my Tahoe would be just the right size.

I do see by your drawing on the grid paper that my radius on the front bottom corner is too large. That's what's good about building it on paper first. You can tear it up and modify it and even start over without costing any materials.

Also, one thing I just noticed on what you put in the Design Library was the step down frame. I like it. Gives you more head room capabilites.


One design question on the frame. As long as I use 2 x 2 x 1/8 rails for the length on the inside of the wheels, and put some 2 in tubing out from the rails every 48 in for the wings, could I get away with using 1 in tube for the cross pieces. (I have lots of 1" and it would lighten up the frame)

I plan on using 1/4 in wall 2 x 2 for the tongue.

If your grid is based on 1 foot squares, I think I will stick with my 12 foot length.

And one other note that I noticed on some pictures of the open door of 48Rob's Cabin Car is that the door window when open matches the position of the cabin window right next to it so that viewing from inside of the cabin is not restricted. I don't know if it was intentional, but seeing Rob's work, I suspect it was. It is a nice little detail. Rob's attention to detail is a mark of a real craftsman.

I am hoping I can do as good.

Dave

[davefullmer]

Speaking about the curves,

Yes, I found there was no easy way to blend the curves on the top front corner.

My bootlegged copy of Auto CAD was lost when my computer got messed up with virus last spring so I had to resort to Delta Cad that my son has.

But Auto CAD has a feature that will blend too curves in an nice smooth transition of the arcs. I think they call in "fillet". Maybe I shouldn't talk about bootlegging AutoCad here. Some one from AutoCAD may be lurking.

[angib]

Dave, from your comments, I'm not sure you've seen all the pages of the PDF profile of the Cabin Car:
http://www.angib.pwp.blueyonder.co.uk/t ... in-Car.pdf

You can read off the position and radiuses of all the curves, except for that awkward front top curve.

If you've got CAD, then just download the DXF file from the Cabin Car page and you'll import everything.

Your plan on cross-members sounds fine, though I've got one area of concern - if you join 1" tube to 2" tube, the bottom of the 1" tube will be pressing into the middle of the 2" tube, right where it's not very strong. In time, the 2" tube will crack there.

The alternatives are (1) to fit a little bracket that ties the bottom of the 1" tube to the bottom of the 2" tube, (2) add a doubler to the side of the 2" tube to take the extra stress, or (3) not worry about it.

Andrew

[davefullmer]

I can see what you're saying but maybe I didn't make myself clear enough.

What I didn't say was that I would still use 2 inch at both ends of the frame and one in the center just for good measure. I figured the 1 in tubing would serve as floor supports. Also, I don't see the need to use anything but 1 inch to construct the recess of the dropped floor. I'm planning 2 single beds with the door opening between them and the recess between them but only between the long 2x2's carrying the bulk of the load.

I also would think the wings should be out of 2 in tubing also.

Thanks for the ideas. What I saw in the designs was the the 4 layouts. I'm not sure if Delta CAD can import those files or not.

I appreciate your attempting to keep me out of trouble. I definitely don't need the frame work I put under my bandsaw mill trailer. That was 16 ft long with the rails out of 3 x 6 x 1/4 tubing. I didn't want the rails to bend when I put a log on the mill.

Besides, I'm having fun.

Dave

[davefullmer]

Andrew,

Tonight, I was working on the frame some more using measurements of my axle arrangement on my bandsaw.

My son and I set the mill up stationary and the axle and wheels are being used any more. The tires are 235 75 R and measure 15 in radius. I was thinking about stealing the axle for my tear.

So I fit everything together and discovered that the floor would be 22 inches of the ground and the roof would be 6 ft 10 in from the ground. I don't think I like that height. My Tahoe is about 6 ft 4 in and the tear would stick up in the wind path. Also, the tear would end up 6 ft 8 in wide. Which is about 4 inches wider that the Tahoe.

So, I think I need to build the axle shorter and with smaller tires. Maybe a 14 in tire. I don't think I want to go as small as 13 in.

Delta Cad doesn't not have an import feature.

Shortly, I am going to have a better CAD program that will though.

Then I'll have to do all this over, won't I?

Dave

[eamarquardt]

Ya know, the windows on your design look a lot like rear side windows from a VW bug. You might want to consider using them as they are probably abvailable dirt cheap (I might even have 4 I may not need) and the rubber to mount them is also available dirt cheap from many sources. The windows are tempered and are very strong.

cheers,

Gus

[davefullmer]

You know Gus,

Rob said the same thing. I had asked him if his opened and he said no.
He also said big mistake, and then he suggested the bug rear windows. He thought they opened out from the rear, but I don't recall that they did.

I wore out 5 of the buggers back in the '60's and '70's.

There is a (or was, I haven't been by in a couple years) location about 30 miles away where a fellow has many old ones sitting around his property. As soon as I have a chance, I want to go talk with him.

Thanks for the suggestion. Any ideas on how to open them?

Dave

[eamarquardt]

VW did, as an option, offer rear windows that cracked open using a hinge at the leading edge similar to the way my rear windows open on my Windstar van. They, however, weren't that common and may be difficult to find. How bout installing the windows in a wooden frame that opens. You get the shape you want and opening windows. By the way, I bought a Chey S10 and the A/C works intermittently. The relay under the hood is good and the clutch is good. Got on All Data and it looks like the the basic deal is that the Control head (with the knobs and thermostat) sends a signal to the trucks main computer which then operates the clutch relay and poof, you have A/
C. I (and others) suspect the control head. Is there any way to test this?

Good luck and thanks,

Gus

[angib]

Delta Cad doesn't not have an import feature.

I'm surprised - I thought every CAD program nowadays read DXF files.

Actually, I just looked on the Delta CAD web site and it says:

Reads and Writes .DWG, .DXF, and .DXB files

Andrew

[davefullmer]

Hi Andrew,

It may be that I just call up the .dxf file that I download and click open it in Delta CAD. I'll have to try that. Then if I can figure out how to set the dimensions to the length I want. I noticed something about setting the scaling. There may be an option there. I'll have to try it.

Cad drawings is not my expertise. I work mostly with logic circuits in the manufacturing industry. Punch presses, Automation for assembly and manufacturing machines, etc. Any designing I do is electrical circuits and the place I work expects me to design the logic while I am installing it. (Almost)

They don't even let me have a desk. Right now I am trying to restore the inch, single stroke, and continous mode on an old press that has been worked on so many times that the control panel is a regular rats nest. I told the bosses to go to their office for a few days and let me straighten out the mess before I even try to figure out where someone messed up the circuitry. Talk about fun. But today I had some success taking all day yesterday rerouting and dressing up one of the connection boxes.

The press was only functioning in inch mode and I was able to adjust the cam switches so that I could get it to operate in single stroke mode. Tomorrow, I start to figure out how the original circuit was supposed to work in continous stroke mode.

If I have to redraw any circuitry, I'll have to do with pencil and paper on a plywood board out next to the press. That's what they allow me to have for a desk.

Oh well, some one has to do it and since no one else in the plant understands, I can set my own pace and tell them this is what they get for allowing non electrical maintenance people to troubleshoot and repair the machines.

Wow, did I get off on a tangent or what?

Messing with this idea on building a Tear keeps me sane. I have several little nitty gritty things I want to check out with the cad program to see how they fit. My biggest concern right now is figuring out how to construct a dropped axle so the whole thing doesn't set too high.

Enough rambling. back to the drawing board.

Dave

[davefullmer]

I have a plan for the frame and axle. (I think)

I did some more sketching in my CAD program and have figured out what to do to make a dropped axle using springs and hanger kit from Northern Tool and an axle from TSC. The TSC axle is a straight axle with no camber and rated for 2000 lb.



This week I will be getting some 2 in steel tubing delivered to the plant where I work. My supervisor who is the maintenance foreman has told me that we can take all the parts to his home shop where he can keep me safe regarding welds, etc. He is a real professional when it comes to fabricating any type of machinery. (You should see some of the machines our 5 man Maintenance department has built in the last couple of years)

At any rate, I think I will be starting on the frame and axle by the end of the week.

Dave