16 foot single wheel unusual TD build

[angib]

I don't see a problem with that universal joint - except that it may wear a bit quickly when subjected to forces it wasn't intended to carry. But then it is likely to become sloppy, rather than fail catastrophically, so that will be a warning.

But the problem I see is that cutting off half the Rabbit axle has removed the ability to hold the single wheel upright - in the Rabbit that relies upon the two sides being present. So i can se that you will need to weld on a brace where the 'beam' of the old axle used to be, plus a bearing off to one side to stop the trailing arm from twisting away from vertical.

[WeirdDogGuy]

I don't see a problem with that universal joint - except that it may wear a bit quickly when subjected to forces it wasn't intended to carry. But then it is likely to become sloppy, rather than fail catastrophically, so that will be a warning.

But the problem I see is that cutting off half the Rabbit axle has removed the ability to hold the single wheel upright - in the Rabbit that relies upon the two sides being present. So i can se that you will need to weld on a brace where the 'beam' of the old axle used to be, plus a bearing off to one side to stop the trailing arm from twisting away from vertical.

Yes, that's right, well spotted. If you look at my new swing arm in the pix after I cut it, I now have a cantilevered hinge. So last week, I started to make another hinge bracket to support the end of the hinge pin. But then my finely crafted harbor freight angle grinder went into hand grenade mode, so I'm back to welding while waiting for a new grinder to arrive. The new support bracket that I'm building will pretty much be a mirror image of the VW bracket on the other side. That hinge is pretty stout. It may be hard to see in the pix but the hinge pin is encased in a very thick rubber sleeve for impact loading. Should do the job. I know people like to see pix so I'll try to get some this w/e.

Thx for your comments.Andy

[WeirdDogGuy]

Here is a close-up of the new swing arm hinge pin. Not a very good pix but you can see the problem here, the hinge is now cantilevered off of the single bracket. The solution may seem obvious; build a copy of the bracket in the pix and slide it over a new (longer) hinge pin. But there's a big problem-I have NEVER been able to get one of these pins out. It is a .460 IN (so maybe 12mm) bolt and they are MURDER to remove. I suspect (but do not know) that the rubber sleeve bushings are injection molded onto the pin at the factory and must be replaced as an assembly. But there is enough room on the end of the pin to sneek a diy bracket on. It is 1/4 IN thick, 2 IN steel angle iron with a hole drilled in to take the 12mm pin. It will increase the bearing area of the pin only slightly. It's real value is to support the end of the pin so it is no longer cantilevered. Since it is now captured, it can maintain the geometry that I want and act like a "normal" hinge. I hope that makes sense. BTW, for reference, the caliper is showing about 2.5 inches.

[dodgedartgt]

Subscribed! Looking fwd to seeing this build progress.

Mike in FL

[WeirdDogGuy]

Welcome aboard Mike.

Andy

[WeirdDogGuy]

Gunga Galunga! Look what my neighbor donated to my build:

avll13.jpg (86.27 KiB) Viewed 940 times

So that motivated me to redraw my coach with my new tail lights. I ditched the 1959 cadillac repo lights and drew in my new lights which we believe (?) are from a 1956 Chrysler. I also drew in the rear door for my back room where I'm going to store my mountain bike, The line in front of the new door hatch represents the bulkhead wall that separates the back room from the front room:

newavll(1).jpg (23.54 KiB) Viewed 940 times

I also drew in an unusual design element. I don't know what to call it. it's a comb (rooster) or crest, or rib on the roof. It will stiffen the roof longitudinally. I ripped off the idea from a 1932 bugattii aerolithe:

aerolithe.jpeg (8.12 KiB) Viewed 940 times

It's one of those weird design elements. I like it and I don't know why. There is a skylite near the front of the coach and the rib starts there and extends back to the tail light. Near the rear, I'll french in a LED stop light strip into the rib. So the bottom foot of the rib will contain an LED stoplight. I'd hate to have some douche texter rearend me, so the more stop lights, the better. So I'm getting close to the final design of the coach. This will be close to the finished product.

[KCStudly]

I believe that the "fin" was essentially a pinch seam on the Bugatti. That's where the rivets went that held the two halves of the body together, unless I'm mistaking.

[WeirdDogGuy]

That's possible KC. I'm not sure.

So I wasn't happy with my last design of the coach. I love that 56 Chrysler tail light but I don't like the way it truncates the coach. I think the lines should just flow out to the end. I also thought the roof rib was a bit much. I like it, just not that much. Also, this is a stressed skin structure so when I cut a door opening, I'm removing strength. So back to the drawing board. I shortened the roof rib, now it starts at the back window. The end of it will still have a LED stop light strip embedded into it or perhaps the whole rib-one big LED strip. I redrew the 59 caddy tail light but I tucked it in closer to the coach. I like the way the 59 Caddy light emphasizes the outflow of the coach rear. I also raised the threshold of the door a bit to make the door a bit smaller. For reference, that side door is 36 inches wide. The body flows a lot better now and I'm happy with this version. I might make a couple of minor changes but this the final design:

[Starseeker]

Is it me or does the front fender profile of the '32 Bugattii have a nice TD shape?

[KCStudly]

You will probably want to truncate or round over the trailing tip of the window in the cargo door. Sharp pointing things are hard to trim out.

[WeirdDogGuy]

Good catch KC, that's what I meant when I said "minor changes". I really don't want any sharp corners in any openings. They are stress concentrators, and I don't think they look right. The corners in my side door have a radius of 2 IN. The door window corners will be softened. I drew it late last night and I was just too tired to finish the details. Same for the front corner wraparound windows.

[WeirdDogGuy]

Is it me or does the front fender profile of the '32 Bugattii have a nice TD shape?

Isn't that a sweet ride?

[mezmo]

Hi Andy,

I think your neighbor is mistaken on that tail light. It looks like an mid-1950s
Nash tail light to me. Check this out:
http://www.1954sale.com/search.php Search for 1954-55 Nash tail light.

Check out the 1956 and 1957 Chrysler tail lights on here:
http://socalcarculturesblog.blogspot.co ... ights.html
Either of these would fit your design better as they are both taller. The 1957
is taller of the two, but I think the 1956 looks 'classier' as it is a little more clear
or jewel-like. If you could get one of them and the bumper bulb-end underneath
the tail light , that'd be a very distinctive finish to the body. The 1960 tail light
would also be really a interesting way to finish the body too.

Cheers,
Norm/mezmo

[WeirdDogGuy]

I think you are right and I think it's a Nash tail light. There's a mid 50s Pinafarina Nash in my town. I've seen it and I remember 2 things about that car. 1) The top of the tail light hinges up to expose the gas filler cap and 2) the bench seats fold down to make a bed! (Leave it to the Italians! ) The tail light in the pix above has a hinged top feature, just like in the Nash that I saw. No matter, I want to use the Caddy afterburner tail light since it's more aerodynamic and it draws your eye to the rear shape of the coach. I'm surprised you spotted that!

So I had a little time today to work on my swing arm hinge bracket, and as I was laying out my bracket, something kept bugging me. The geometry looked off somehow. So I clamped some winnowing sticks onto the wheel hub and onto the bracket to make sure that they were parallel. Here's a pix of the layout:

avll18.jpg (183.38 KiB) Viewed 762 times

If the bracket and the wheel are parallel, the distance between the 2 sticks (level and aluminum bar) should be equal along their length. The distance wasn't equal. There is a small amount of run-out. It's not much, maybe a degree or two, but it's there. I can compensate for it when I drill the mounting holes for the brackets in my spine. I don't know if the VW engineers built some camber into the geometry of the original axle or if it's manufacturing error. It's an important consideration and here's why. Let's say it wasn't 1 degree. Let's say it was 45 degrees. Because the tire is not coincident with the direction of travel, it would ride out and the end of my foamy would swing out from the direction of travel. So it would go down the hiway at an angle! It's important that the tire is aligned to the centerline of the TV+trailer. Another way to think of this is to consider a long fire department ladder truck. They are so long, in order to turn a corner, they have a guy steering the rear axle-it pivots! The rear wheel on my foamy shouldn't be turning-not even a degree-it should be going straight. I doubt a degree will matter in the real world but I'd rather have it going straight ahead so that's how I'm going to fix the geometry. The real surprise here is that my eye picked out the error since it's so small. It's amazing what the human eye can do if you take the time to use it.
ThxAndy

[MtnDon]

The eye is amazing at picking out things like that.

The discrepancy may be on purpose. Under way there drag may cause the pair of wheels on their suspension pieces to tow out slightly. It could be the wheel pair have a slight toe in at rest to compensate.