The Old Lady is ready

I have finally completed it! Not only I have managed to assemble my Christmas present completely, I also have taken photos so there is nothing that stops me blogging about it.

So what is it? The most aged member of the Big Car series, the "Auto Chassis" from 1977. It was missing some parts but the seller was so kind that he sent all of them to me. By the way I am very happy with it. It feels like new, I did not find any broken or yellowish parts. My old Technic playing sets from the 80s are in a much worse shape by now.

After putting it all together I found comparison against the other Big Cars natural. Some numbers to start with:

• this is the oldest of all, sold from 1979
• this has the fewest pieces, 610

This is also the one to contain the fewest special parts. For example the front suspension is made of bricks and rotating plates. There are no springs but there are nonetheless interesting details. For example the suspension has a hole in the middle to accommodate the power train from above. The gear rack moves only sideways, not back and forth with steering. Unlike most other Technic models from the age it has an intermediate arm that makes this possible. Another interesting property of the steering is that it is impossible to fit the gears together such a way that the steering wheel is completely horizontal when the wheels are parallel to the chassis.

The power train makes a very massive impression, the four big cylinders after each other would be enough to drive a boat. The gearbox has two gears, in first gear the pistons literally "fly" - I am not sure that this lasts long under heavy playing. In the rear there is no differential. Instead, there is an universal joint keeping the two sides together. I think this can be really easily broken by the torque of the large wheels.

Besides the relatively simple basics there are a couple of interesting details. The first seats can be adjusted forward or rearward with a rack mechanism. The middle part of the rear seat can act as an arm support or can be hidden.

Until I saw it from photos only I did not realize that the engine is shifted one stud right from the centerline - I believe this gave more room to the exhaust and the gearbox. The proportions of the car are also somewhat surprising, it is not wide but very long, probably longer than any of the sportier subsequent models.

One more thing: the assembly instructions come on both sides of a single foldable sheet in 10 main and 27 secondary steps. For comparison, the instructions for the 8448 have more than 150 steps (and pages).



Now if only I would get an 8860... More photos in the album as usual.

Radial engine

I have to admit that besides cars I also have a passion for airplanes. It is no wonder I have started thinking about doing a radial engine (Wikipedia article). This configuration is used mostly on aircraft and it looks like this:


After some skunk work I have decided to implement one based on betula's design. The first prototype is ready and looks like this:


There are some differences though (besides the colors of course). For example in Betula's design none of the rods are fixed to the hub of the engine. To me this lead to some problems in practice. When changing the direction of the rotation it sometimes got stuck. In my design there is a master cylinder attached to the hub. It rotates very smoothly and does not have a tendency to get stuck. The other change is that instead of using a gear in building the crankshaft I use the normal half-pin shift part even though it means the engine got a bit longer.

And how does it look like while working? Like this:



Now if only I had time to build an airplane... (More images in the album.)