hello from germany

[bernd]

Hi together,

Hey Bernd,

Welcome to the forum. What part of Germany are you from? If you like, you can add that information to your profile.

Your english is very good, much better than my German! Have fun and let us see what is different with a German teardrop.

We have people here from all over the world. If you have any parts sourcing problems, just ask, someone has probably already dealt with it. Just off the top of my head I know there are a bunch of people from England, Estonia, Finland, South Africa, Australia etc.

Have fun!

Tschuß

Mike...

<= look. The region i live in is maybe the best place to live in Germany. Very moderate climate, green and fertile, one of our predecessors the "Homo heidelbergensis" lived here, the "Neandertal", where another predecessor (Homo neanderthalensis) was found is nearby, the Roman town "Lopodunum" is now Ladenburg, Heidelberg is a well known town...
Mannheim has the second largest river port in germany.
The layout of the inner city is in squares. Klick the link >Deutsch< language and take a short look. Never thought, that the layout of my hometown is such complicated
http://en.wikipedia.org/wiki/Quadratestadt
http://en.wikipedia.org/wiki/Image:Basf ... n-ww-1.jpg
I live somewhat under the right corner, an the wind comes always from the left

Welcome to the forum, we love our international friends and hope to see you at our International gathering next year.
My son is living and working in Germany (Karlsruhe) at a physics lab for his summer job this year. He will be there until mid August. He's having the time of his life and tours Europe on the weekends.
Good luck on your build.

...and Karlsruhe is nearby too, about 44 miles. I wish your son has a really good time in germany.

Bernd, welcome!

Everybody else, please observe one minute of silence, giving thanks that you don't have to get your trailer past TuV inspection. Guys in Maryland, stop complaining about those amateurs at your licensing authority - Bernd is up against the real pros in saying 'No'.....

That TuV-approved tongue and joining clamp is a really neat combination - I don't believe that you need anything more than that if you built a teardrop body carefully, with strong joints. But of course I do not expect the TuV to agree with me!

Andrew

deep TÜV understanding, thank you!

believing is not TÜVing, even knowing may not help.

News: I was at the TÜV, waited two hours to have a talk for 3 minutes. In general there ist no problem with wood. No sharp edges of course!!! The type approved parts (axle and tongue) ARE the frame, the rest ist the coachwork (body). In general i don't need somthing like a seperate rectengular steel frame under the sidewalls of the tear. The engineer remembered me, how european caravan trailers are made.

I researched the unbelivable details. Imagine your well known Harbour Freight chassis 4*8 without any cross member. The floor of an european trailer on such a frame will be much bigger, about 7*11. It is build from a layer of 1/8inch plywood, then comes a wood (spruce) frame at the circumference and some battens, like a ladder every 15inch. This wood framing is only little more then 1inch high. Isolation is cheap white polystyrene. Then a sheet of 1/4inch Plywood - ready is the floor. The walls are very simple too, and attached only to the floor:

It had a leaky skin, pic found on www (is that ok?)

All the teardrops i`ve seen are build like tanks. As someone (Andrew?) mentioned here before.

To continue with the TÜV-talk: I was told, that the engineer who does the licencing is on vacation till the end of august, and if i have further questions i may consult him.

I hope he had a relaxing vacation when i bring in the tear for licencing.


My plan is NOT to use an additional steel- frame. It will only add weight to a stiff body. Maybe i use steel plates to enlarge the contact surface between the three relatively small connection points of the axle/tongue- frame and the tear body. This will distribute the force smoothly to the wood of the floor. Making the wood floor framing more massive in this areas should be no problem.


Next news: The delivery man ringed, but i was at the TÜV. So he dumped an axle and a tongue at my door. The first thing i thougt was: Wheels and mounting parts are stolen, because the stickers on the two packages spoke of three packages. The callcenter told me, that the missing package is a phantom booking in the system and not yet brought in by the supplier. Lets see...

I'll post pics when the frame- parts are complete.

greetings, bernd

[mikeschn]

Ah, so you are in the south. My last trip there took me to Würzberg and Nürmberg. That was many years ago.

I honestly thought I was going back to Germany this year, to Schwäbisch Gmünd, however, that trip has not manifested itself!

Anyways, all those squares in your town, seems like that what we have here.

And it sounds like you have done your homework on teardrops. You've been lurking for how long?

Tschüß

Mike...

[bernd]

Hi,

Mike, the T&TTT is a very special experience for me. It was the longest time of lurking in a forum ever, without posting or getting bored.


parts are here





weights are:

axle 50lbs
tongue 22lbs
clampings 6lbs
2 wheels 17lbs
lighting, fenders 7lbs

together 102lbs (46kg), the rest up to 660lbs (300kg) is for the tear body and bed and ...comfort.

I played with curves. Gimp is an application like photoshop, part of my Linux distribution UBUNTU. You can lay a grid, and draft traces with a wonderful auto curve funktion. Disadvantage is, that i found no way to save the resulting pic together with the grid, so i used the screenshot funktion. (EDIT if you save as a jpg it seems to work including the grid.)

Just set a point by holded leftclick, move the mouse still holding leftclick and you get a position marker and the pointers. Do the same at another position to get a trace. Modify the trace by playing with the pointers.

This layout is made with 3 positions, two at the ends and one at the highest point. The grid is 10cm (sorry, i think metric ), three squares aproximate one foot. It is not the final layout, just a result of playing.



i did not find an online calculator giving me foot and inch with one calculation step, for example 6foot, 5inch, any suggestion?

I visited the local wood supply. The plywood i can get is Birch in sheets of 118*95inch (300*150cm). Diameters 5/32 (4mm) , 1/4 (6,5mm) , 11/32 (9mm). The first two are warped like leaves in autumn, the last is "only" bowed. Summer is not a good time to buy unwarped plywood, i was told. Excessivly warped, thats no fun to work with. I wanted to use 5/32 for the underside of the floor, 1/4 for the top side of the floor and the walls, and 5/32 for the roof.

It seems, that i have to build accurate frames first, and cover them with the warped ply. But i hoped to use the Plywood as base for the framing work. Glueing frameparts to a flat surface is much easier than to build a bare frame. I`m not lucky... i don`t even have a real flat surface. So i have to fiddle the floor frame together with an aluminum level and shims to the uneven floor you see in the pics? Then i have to buy accurate framing wood?... expensive...

I'll get it in

Welcome Bernd,
I was stationed in Mannheim in 1973-74. (Army)
I had a car, so I somewhat know the restrictions for any thing that goes on the roads. It can be frustrating, but it keeps the junk off the roads.
Good luck and again, welcome.

This were the last years of the famous detroit 2 stroke diesels? Relatives of mine live in Käfertal. Every time i visited them as a small child i heared the sound of this trucks at the big Käfertal crossing. I remember this sound like it was yesterday. What a fun to hear detroit diesels on youtube again.

Greetings, Bernd

[mikeschn]

Ah, so you are playing with splines. That's a very powerful way to make really nice curves!

As for the conversion, since you are working in cm, just divide by 2.54 to get inches. then plug the result in here:
http://www.metric-conversions.org/lengt ... o-feet.htm

Your profile for example is 125 cm high or 49" or 4' 1"

BTW, I used 12.7mm birch plywood for the floor, and that was with a frame.
I would probably build a nice frame out of pine and cover it with birch ply, at least 12.7mm.

I would like to hear Andrew's suggestion!

Mike...

[angib]

I think if you want to build a really light body, then you need to think of using one thin single skin with good framing. Using double skins (that is, a ply+framing+ply sandwich) is very strong, but those two skins add weight even if they are very thin. If you stay with a double-skin floor, then your 4mm and 6,5mm sound good. I think you should be able to build the sides out of 4mm with good framing, but it will be easier to use 6,5mm.

Estimated weights are:
4+6,5 double-skin: 10 kg/m2
6,5 single-skin: 7 kg/m2
4 single-skin: 5.5 kg/m2

Estimated areas (for a 2,4 x 1,2 x 1,2 body) are:
Floor: 2.9m2
Walls: 4.8m2
Bulkhead: 1.5m2
Roof/hatch: 10m2

That gives about 130kg for the main structure of the body plus the bulkhead (the panel between the galley and the cabin) which I think fits your total.

When you join the ply and the framing, the pieces need to be flat because gluing them together will lock in any curvature - so you have to work out how to support the pieces, flat, while gluing. It is probably easiest to lay down the 6,5mm floor plywood and then put packing under that to get it flat. Then when you have assembled the floor, leave it on the packing and use it as a flat base to build the side panels on.

I don't believe it is necessary to start with bad plywood - instead of your local wood merchant you need to find a plywood specialist who can supply good plywood. It will be easier to do that than to work around the problems bad plywood will cause. If you find a good plywood dealer, they will stock "marine plywood" - I don't suggest you need to buy this expensive plywood, but it will show you what good plywood looks like and if the dealer doesn't sell it, he isn't a plywood specialist!

Andrew

[bernd]

Hi,

Mike, thank you for the convenient calculator!

I think if you want to build a really light body, then you need to think of using one thin single skin with good framing. Using double skins (that is, a ply+framing+ply sandwich) is very strong, but those two skins add weight even if they are very thin. If you stay with a double-skin floor, then your 4mm and 6,5mm sound good. I think you should be able to build the sides out of 4mm with good framing, but it will be easier to use 6,5mm.

Estimated weights are:
4+6,5 double-skin: 10 kg/m2
6,5 single-skin: 7 kg/m2
4 single-skin: 5.5 kg/m2

Estimated areas (for a 2,4 x 1,2 x 1,2 body) are:
Floor: 2.9m2
Walls: 4.8m2
Bulkhead: 1.5m2
Roof/hatch: 10m2

That gives about 130kg for the main structure of the body plus the bulkhead (the panel between the galley and the cabin) which I think fits your total.

When you join the ply and the framing, the pieces need to be flat because gluing them together will lock in any curvature - so you have to work out how to support the pieces, flat, while gluing. It is probably easiest to lay down the 6,5mm floor plywood and then put packing under that to get it flat. Then when you have assembled the floor, leave it on the packing and use it as a flat base to build the side panels on.

I don't believe it is necessary to start with bad plywood - instead of your local wood merchant you need to find a plywood specialist who can supply good plywood. It will be easier to do that than to work around the problems bad plywood will cause. If you find a good plywood dealer, they will stock "marine plywood" - I don't suggest you need to buy this expensive plywood, but it will show you what good plywood looks like and if the dealer doesn't sell it, he isn't a plywood specialist!

Andrew

No, that is no plywood specialist. The ply was maybe fine, but it is stored at uncontrolled climate on uneven surfaces. It's maybe the best to start with getting a precise floor framing together. Thats what i can imagine as the easiest way under these conditions. To my surprise i found cheap, relatively straight, well stored spruce squared timber 1*2inch. It is raw cut, but with an obviously fine saw, and it measures really 1*2. Sawdust will cure a lot of problems, so it`s the best to start...

Thank you for the weight estimates!

I found this:
(Note the scrappy apperance of this brand new "made in germany" axle...)



It`s diameter is 0,07 inch (1,9mm), so i have to stack two or three? Elastic but sturdy like a leave spring? Bolting this to the axle without elastic wood inbetween will give a correct bolting, and this number of wood screws screwed in the floor frame will give a sufficient joint? Of course the frame has to cover the whole screwing area.

What do you think?

It would be fine to have an even floor inside, but if it`s not enough for the TÜV i may drill bigger holes, use threaded screws, and use another plate as washer at the top side of the floor. I think it`s overdone... ...and weakening the frame.

Greetings, Bernd

[angib]

I say 'No' to the 'bolting plate' - I think you must bolt through the floor of the trailer and use a big washer under the head of the bolts. Otherwise there is a big risk the axle will be pulled off the trailer, which has happened.

The easiest way to get big washers is to buy a piece of flat bar, say 50x3mm, and cut short lengths of it. Here are some diagrams I did about exactly this question a year or two ago:





Green is side wall, blue is floor, red is floor framing - where the axle mounts a large piece of strong hardwood (such as oak) should be added as floor framing - the framing everywhere else does not need to be so big, so this piece of wood is only needed locally.

Remember: what you are aiming to do is to connect the axle to the side wall (the floor is not important) - the axle is bolted to the (red) floor framing and that is glued to the side wall, so this is a good connection.

Andrew

[Miriam C.]

to the playground Bernd. I see I am late to the party. I like the axle and it looks like it will make a great, light weight teardrop.

Enjoy and keep us in and stories of the inspectors. We have our own regional difficulties as do the EU.

Where's That Finn. I know he has some stories.

[bernd]

Hi,

now... ...the first real problem... ...a chain of problems, leading to this problem.

Thanks a lot for giving your clear thoughts!

Of course i tried to get a really suiting axle/frame for my project. "How many axles of that special built do you want to order" was one of the best answers. Noone has short axle taps in stock to weld to the crankarm. Even the crankarm itsself you see at my axle is a special of this manufacturer, others only have bowed wider cranks. An available axle with slightly better measures would have cost twice as much to reduce the problem by 1 inch, means still far from the sidewall. Heavier too. And with rubber for 1650lbs.

In short: I had to decide if i want a teardrop with overdone big and wide, heavy, and offset rim wheels. Or small wheels at a funny distance to the body -
or to accept complications having the support not under the sidewalls.

Then i found this picture of that floor repair at an european caravan trailer. There is nothing exept the wood floor (1/4, 1.1inch thrifty framing, 1/8 ) between the frame and the walls. You can say the frame is screwed midway to the torsion boxes floor. I was stunned

That is what i think: contrary to the widely used teardrop designs the walls of an european trailer are more an insulated visual cover than a wall. They are made of 1/8 dekor ply, a little bit of wood, can't call it frame, and an aluminum foil, loosely glued together. If you would step hard straight on the bare egge of these sidewalls the inside ply would crack, and the outside foil would wrinkle, even with a little wood in the edge. The wall covers are more stiff than any squared timber. I don't mean strength, i mean timber is more flexible than a sheet of ply or aluminum. With an european trailer wall it is neccessary to distribute the forces carefully to the full lenghth of the wall. That is what that flexible wood floor does: distributing the force from the frame carefully and flexible to the whole length of the walls edge. The strength of such a trailer comes from flexibility.

An usual teardrop design consists of and is based on serious ply walls. Even with light framing and 1/4inch ply covers it would be impossible to crack such a wall by stepping straight on the edge.




The superleggera design is the most consistent lightweight tear design i`ve ever seen. The combined V-tongue/frame design with torsion axle is brilliant. But with the V beginning at the clamping piece of my "type approved" straight tongue the angle is bad, and the crankarm collides with the frame. But there is a TÜV-Rule... if the tonge is an integral part of the frame, then no type approval is neccessary. But in a book about trailers, published by the TÜV itsself, there is the explicit warning that not approved "part of frame - tongues" are subject of discussion with TÜV engineers.
...type approved V-tongues ARE available, looking just like the superleggera frame, but heavy, and rated to 2900lbs.

Next is, that the hight of the fenders above the small wheels gives a pleasant sitting height to tie the shoes and to have a first look at the rising sun. So i planned to have a shelf holding the fender, the backlights, and to sit in the door above the wheel. The door partly above the wheel has to do with the necessaryly light galley and hitch weight... there is not much wall above the axle...

So i ended up with that perforated piece of sheet steel... and i want believe, that it is possible to connect the given axle to the body with plates and suitable wood framing in the floor. Bigger plates? Same plates, but bolting trough the wood? Bigger and bolting through? Other idea?

I'll sketch up a wooden floor framework next

Greetings, Bernd

PS

Hi,

to the playground Bernd. I see I am late to the party. I like the axle and it looks like it will make a great, light weight teardrop.

Enjoy and keep us in and stories of the inspectors. We have our own regional difficulties as do the EU.

Where's That Finn. I know he has some stories.

The EU ist the greatest enemy of the German TÜV, not that the EU fights against the TÜV, but the TÜV feels attacked. This leads to a question: Is there any supplier in another EU-state selling something like the harbour freight utility? If, than it has an EU approval, German and EU approvals are equal by law...

[angib]

This leads to a question: Is there any supplier in another EU-state selling something like the harbour freight utility? If, than it has an EU approval, German and EU approvals are equal by law...

Yes, here you are, for sale at Northern Tool UK:



But trailers do not need to pass any approval here in the UK (apart from the road laws enforced by the police), so you could not claim it was "EU-approved" - in theory as it is for sale and legal in Britain, you could buy it and register it in Germany. But do you think the TuV accept EU free trade laws are more important than their own rules? I don't think so!

Andrew

[SuperTroll]

Bernd...we here in the US are a little more "Relaxed" than our German friends....here in the State of Alabama, we allow a LOT of design freedom...look at this picture, it will let you see the degree of freedom we have here.....

[angib]

Actually, Bernd will have the last laugh on you - that wooden bike is from Germany! Not surprisingly, it isn't registered for the road but is seen at bike rallies.

Here is the original photo with a German advert on the bus shelter.



But then doesn't the existence of a bus shelter prove it's not America?

Andrew

[bernd]

Hi,

it's using that plates
Few more levers and rods, and the springs for the front suspension may be mounted unter the seating area





1*2 timber vs. 1 1/2 Ply (2*3/4):



Greetings, Bernd

[SuperTroll]

Actually, Bernd will have the last laugh on you - that wooden bike is from Germany! Not surprisingly, it isn't registered for the road but is seen at bike rallies.

Here is the original photo with a German advert on the bus shelter.



But then doesn't the existence of a bus shelter prove it's not America?

Andrew

Yah, this I knew already from the paving stones, and the obvious cut and paste on the Alabama emblem over the bus shelter addy....Just makin a funny because it's the truth here in Alabamy.....

I can wire the doord shut with bailing wire, fun without an front end cap,,and wake the dead with no muffler.....all the while computing my miles per quart of oil, because Alabama is a no inspection state... thas right folks...if it moves ya kin run er on the roads down heah.....

[bernd]

Hi,

sawdust at last
... 1 1/2 best birch ply




I think to use one of these plates with an additional 1 1/2 washer on top, one plate at the bottom, bolt through, with a washer, additional crinkled spring washer(s) and a nylock nut. The Bolt is M12. Birch ply is hopefully hard enough to keep enough tension. (See the sketch above for further details)

Not ideal, any suggesions for improvements?

Greetings, Bernd