Matchbox 1/72 Saab J29 F Tunnan by speedgraflex

[speedgraflex]

Thank you both very much, Mike and Carlos.

Carlos, I can’t believe you found that angle. I thought I’d visited every online walk-through, flight show album and museum feature online.

Well, the egg’s on me. Where was this? Or more important, how did you search for this?

I’ve been adding styrene strip to make the landing bay interior. It’s fairly fast work, actually. I personally count 18 ribs per side but I am able to fit sixteen in the space provided which is enough for me at this point. It’s always easier to scratch build in the end.

What I’ve been thinking about is adding weight. With this short stubby fuselage design I can add weight in the center section. That’s why I needed to know whereabouts that engine was situated.

Thanks again. You both really helped me.

[Bolleken]

Hi Bruce, you know I've built this kit some years ago.
On page 34ff of the following build-report you might get some inspiration for your model as ad-on while you actually don't need any.

https://www.flugzeugforum.de/threads/4b ... 87/page-34

You can also see, that my intake solution is far away from what you are going to do. Nevertheless it is deep, which is half of the rent (as we say in Germany).

If you don't want to build the engine blades itself you might work with a photo print. Carlos's image is a good reference. Print the blades on a paper and stick it to a plastic sheet. I guess it will do the job once glued to the tube.

[speedgraflex]

Marius!

Thank you for sharing your thoughts. I need as many ideas as possible.

If you don't want to build the engine blades itself you might work with a photo print. Carlos's image is a good reference. Print the blades on a paper and stick it to a plastic sheet. I guess it will do the job once glued to the tube.

Yes, I think I’ll be building a shadow box and a quite short one. I think I’ll be using more plastic card.

[Bolleken]

Did I send more than one engine-blade-part for the 190TL to you? If yes you might consider to bash it for your Saab.
Again, just a thought.

[speedgraflex]

I believe you did, Marius! Something I need to show you is the interior configuration with the cockpit piece. It appears that the cockpit slab blocks where the turbofan? would be placed.

I found a rudimentary image from MIT that explains how a comparable system works (I think) but I’d rather open the fuselage halves and show you the space inside. At the moment I’m thinking I’ll add a short piece of tubing made from rolled card painted in a slightly darker aluminum and add a blocking piece. There still might be enough room to fit in your 3D designed and printed piece.

I’ll have to wait until I can find time, though. I’m pressed at the moment.

[Stikpusher]

I believe you did, Marius! Something I need to show you is the interior configuration with the cockpit piece. It appears that the cockpit slab blocks where the turbofan? would be placed.

I found a rudimentary image from MIT that explains how a comparable system works (I think) but I’d rather open the fuselage halves and show you the space inside. At the moment I’m thinking I’ll add a short piece of tubing made from rolled card painted in a slightly darker aluminum and add a blocking piece. There still might be enough room to fit in your 3D designed and printed piece.

I’ll have to wait until I can find time, though. I’m pressed at the moment.

The cockpit tub is probably too deep or incorporated with the nose wheel well. The intake duct should sit between those two items with the cockpit tub on top of the duct and the nose wheel well beneath the duct. And in 1/72, a large diameter drinking straw might be a great item to use for the duct. At least it would be seamless.

[speedgraflex]

Thank you, Carlos!

Here are two relevant excerpts from the MIT white paper which was published in 2004.

I’m learning so those more knowledgeable should skip this. To be clear, I’m not throwing this in to waste space but to help me understand what should be there in order to cobble an acceptable solution!

Plus, I just watched an “online documentary” interviewing Frank Whittle who stated categorically he got there first but the War Department nixed his design.

History

Hans von Ohain of Germany was the designer of the first operational jet engine, though credit for the invention of the jet engine went to Great Britain's Frank Whittle. Whittle, who registered a patent for the turbojet engine in 1930, received that recognition but did not perform a flight test until 1941. Ohain was born December 14, 1911, in Dessau, Germany. While pursuing doctorate work at the University of Gottingen, he forumulated his theory of jet propulsion in 1933. After receiving his degree in 1935, he became a junior assistant to Robert Wichard Pohl, director of the university's Physical Institute.

Granted a patent for his turbojet engine in 1936, Ohain joined the Heinkel Company in Rostock, Germany. By 1937 he had built a factory-tested demonstration engine and, by 1939, a fully operational jet aircraft, the He 178. Soon after, Ohain directed the construction of the He S.3B, the first fully operational centrifugal-flow turbojet engine. This engine was installed in the He 178 airplane, which made the world's first jet-powered aircraft flight on August 27, 1939. Ohain developed an improved engine, the He S.8A, which was first flown on April 2, 1941. This engine design, however, was less efficient than one designed by Anselm Franz, which powered the Me 262, the first operational jet fighter aircraft.



Ohain came to the United States in 1947 and became a research scientist at Wright-Patterson Air Force Base,the Aerospace Research Laboratories, Wright's Aero Propulsion Laboratory, and the University of Dayton Research Institute.

[cbaltrin]

And to follow up… I found this shot looking down the intake to the compressor fan face… no plumbing



That’s a typical jet intake.

That's odd. By looking at the other photos , it appears the engine sits lower than the intake opening. Does not seem like it would be a straight shot from one end to the other?

[Stikpusher]

I do not know how accurate this line drawing is, but the center line of the intake and exhaust look to line up perfectly from this angle.

[speedgraflex]

My research indicates that the design is a central tube, much like the diagram Carlos posted, Chris. I need to verify that the kit design follows form, which is a question!

Carlos, I believe you’re right that the platform base added to the model is in the way. I should verify all of these things before proceeding.

Thanks, gents.