Gallery – VDT (English captions)

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- A pressure tank – a very impressive load! -

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The prototype! Really a very special load - and one which I would like to transform to a model! At least that's my opinion.

This so-called ''Variable Density Tunnel'' used by the NASA for research and development of the aviation. Inside - a wind tunnel.

An high interesting picture for me, how one of the end domes is prepared for riveting. And that with steel segments of 2 1/8 in thickness! (54 millimeters!)

The ''Tunnel'' on arrival at Lengley, VA. Also a ring wrench for screwing down the cover of manhole was included! - And how it appears, the tank was rolled (!) from unloading pier to its end position on heavy timbers.

A more picture which has given now more clarity on the design of the manhole.

One cannot get more details if you will see this large view of the door! And this picture also substitutes every drawing.

A look into the tank from the opposite end, yet without installations. At other end the manhole with the opened door.

Again a picture of prototype. Here an inside view opposite to the manhole, where the propeller is positioned - for generating the ''wind''.

Here a sketch with installations and the air flow, if you cannot imagine how the wind tunnel will work inside of a closed pressure tank.

And as last - the VDT on its last way to exhibition park of NASA Langley Research Center as a ''National Historic Landmark'' of USA.

Preparations for the construction of my tank, drawn as closely as possible after the prototype. Whether the project will be a success? Dia of tank - 2''.

These are the commercial available parts for the tank, a plastic pipe and clear half globes - originally as self-decorating parts for christmas trees!

Now an embossing plate was made after the sketch before, which should be drilled as accurately as possible. The short rows of rivets are absolutely sufficient.

My ''light table'' (a LED panel) as working table for pressing the rivets. For better visibility a sheet of paper is interposed, which attenuates the light intensity of something.

The first result is probably quite well usable. Only the tip of the ''trigger'' was new to grind, because that must be as round as the rivet heads!

It will be better and better with each new attempt! Right a first sample still with some inaccuracies, however it's good enough for next tests where I added a second styrene sheet for the final thickness.

The next step - the rivet holes for the connecting plates of the boiler segments were drilled in the embossing plate. Again, highest accuracy was needed!

The first seam plate, embossed, cut and glued. I think that this is good to use as a first sample. Is the seam maybe a bit too thick?

Another test, but with a more extensive construction. Again is about the question - are course plates and seams too thick?

The same object once again photographed with a bit more daylight shows that the elevations here are substantially reduced.

Now the realization with thinner rivet sheets - here the first tank section.

The second section. I think that the thinner courses are looking more realistic than my first attempts.

So are looking the transitions to the domes. The courses were positioned a bit over the tube ends and so I can glue the domes inside on these transitions.

So or similarly the tunnel will look in future. However, a plenty of work must be done before finishing. On each case, a lot of rivets must be added yet!

Drawing of rivet arrangement at domes - a job which will probably become not very simple!

Indeed, ''my'' dome ring seemed to me considerably too large. So I printed out the needed parts and I ''pasted'' them on one dome with much soft-making water. And see there, it fits!

It was unambiguously the easier way! Printing out the drawing with rivet positions of ring flap and then to transfer them on the brass sheet.

I would be never reached so exact positions of so many holes by scribing as you see here at my embossing plate on the light table.

One of the first embossed foils. The large center hole must exist, so that the styrene sheet can better extend.

Now, finally - a first glued rivet ring as an attempt, but with a few inaccuracies yet. But there is not a way for success without a little bit of trying.

The cover of the manhole including the frame are on work. Looks a little bit bewildering yet, or?

Ready for the installation into the dome. These were a good number of small parts, but this thing looks interesting, I think.

I have still built a simple and fast made jig to secure out the exact position before gluing. With this it was a walk in the park for precise positioning.

And this picture once again from above because it looks so nice.

The caps of both domes are completed. The right end with the shaft passageway for the propeller was like an home match compared with the left dome with the manhole!

So between, ballast must glued in the basic body, because the domes will be soon glued on. And the car has no big own weight.

The last embossing template is prepared (right) because the butt straps for the dome segments have again their own and different dimensions.

Clearly cognizablely. It leads the way and with big steps on the end to, at least what concerns the container.

Ready! The first picture!

Here especially clearly to see and for a comparison, what the tank is for a big hunk - 15 ft in diameter (4.56 m) and 34.5 ft long (10.50 m).

Immediately once again this picture because it is so nice. However this picture were shot for a comparison with prototype, look the previous picture.

And still a small fun, refered to picture of the prototype. Can you identify the manufacturer? - ''Bernhard's Model Train Mfg. Ltd.'' Including the correct weight (of model)!

Now, the flatcars of Red Caboose have arrived and the next step will be to build them. Only one is necessary for the tank, however the second one will be unmodified build as first - and I think that I could use it as idler car.

Lead is exchanged against the original steel sheet and so the weight raises from 29 to 39 grams. Not yet a lot, but this was absolutely necessary for this light weight model!

The second car must be shortened, because the models represent 42' long cars, however, this car for the tank must be 36 feet long only!

Also the frame must be shortened and modified - several times sawed and glued together anew (in front).

The brakes are installed completely - an AB-brake on original model on top and a contemporary split-K-brake on shortened car below.

The brakes are installed completely - an AB-brake on original model on top and a contemporary split-K-brake on shortened car below.

A look on front ends, on shortened model on left a Carmer coupler lift bar, as it was common around 1920 on many eastern railroads, on the right after the AAR standardisation.

The short model in front is this what I needed for th tank and it received arch bar trucks and Carmer lift bars how the prototype on that time.

The Carmer coupler lift bar here again a little more clearly at model on right. Absolutely, this is a simple solution, nevertheless this lift bar was rejected by the AAR as a general solution.

Now, in the end, both on the picture, car and load. And almost so how on the photo of the prototype! Of course still without color.

And there must be still a second picture with this immense load, of course!

Of course the end with the manhole is much more interesting! A lot of additional details are to seen on this side. I hope also if the color is on it!

Of course as expected with a perfectly done aging! I think that you can see the long service time at the model already on a first sight!

This is the transport car for moving the fat pressure tank, very close built and excellently lettered to prototype design despite some differences in spacing of stake pockets.

A well modeled brass model which has received an excellent and very realistic weathering also! Would you like to paint an expansive brass model in same manner? I have had a lot of misgivings before!

Now the pressure tank is also painted and lettered. A really excellent work by my friend Jörg from Leipzig. And immediately it goes on with questions. What kind of fastening tapes will be the correct one? Steel would be probably right. And what for a color?

OK, darkly would be the best one, I think! Should I lay the strips directly on the tank or with a wooden underlayment for protection?

No, a protection must not be at 53 millimeters of wall thickness - more than 2 in. But a diminished protection to protect the rims on the flaps! (However I had rather the presseded rivet heads in my head which should be protected probably more than these of prototype.)

And this is the pressure tank now how it looks - mighty, gigantic - as Egon of the Olsenbande said always. (Sorry, an often used phrase from a movie of Danmark, well known here in Germany.)

Here the other end on opposite to the manhole where the drive shaft is led for the propeller into the tank.

The fastening of the tank using the stake pockets of the flatcar - properly stretched by nuts. These press against counter bearings which are pocketed from below in the stake pockets. And these counter bearings are fixed from the back with wooden wedges - very identically to American praxis of that time.

My small permanent companion looking on my works who seems to ask according to my opinion whether everything is in order. How is with a gliding protection of the tank in moving direction of car?

Allowedly, it was my friend from who threw up this question. And so I have thought about the fact that in spite of the transport with special and slow running train maybe however, thus a protection could be right. Possibly in this kind?

Now, I have rejected the idea of such an immense load protection. At end it was become a more simply one because this fixing will be a temporary one for a single run. Maybe I had fallen in love a little bit with the solution of the Flatcar with SHORPY.

The first pictures from moving the painted pressure tank, which is pulled by the small G1 as an Extra train - on a large layout while a model train exhibition.

Street running through ''Narrow Village'' - not an extraordinary situation in USA, however with an extraordinary train load which needs an Extra train.

Certainly there were railroad fans again who have climbed the highest hill in the surrounding to shoot this picture.

The 'Extra train' on a siding, such a train has now once no precedence. But the engine would have needed no a interruption, it ran very reliably round by round while several days. A magnificent result!

This here was e very cramped postion at the freight shed. However all was ok if also with one millimeter clearance.

Running along the rails, mile for mile (more exactly meter for meter) ...

... here on a large layout, session for session and day by day while an exhibion in Dresden, Germany - February 2016.

Now also a video with the VDT on move!

Would you like to ask for the
number of embossed rivets on the tank?
- Exact 3612!
A quite large quantity, or?

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