The
Bismarck

The following pictures show the first RC ship I ever built. Sadly, it is no longer in existence. As I was carrying it downstairs our huge dog decided to come belting upstairs and swept my legs from under me, it was save myself or save the ship. I saved myself. The ship landed at the bottom of the stairs in a fractured heap. The bulk of the joints had flown apart with the impact and the tumbling down the stairs and was next to unrepairable (my heart wasn't in it after all the time I'd spent making it, 12 months). Anyway, I do have loads of photos of it and may yet build another.

This is her, the Bismarck. Totally scratch built with a custom made 7 channel transmitter/receiver (that didn't work particularly well, I later found out it was a duff circuit anyway :o( ).

She's 7' long and 12" wide at maximum beam. This project took a very long time because I had no plans and no computer (this was about 12 years ago now). My brother had a magazine called War Machines and inside (centrefold, no, not the kind you guys like) was a 'lithograph/artisty" drawing of the top side and front view. I sat on the living room floor for months with a calculator, a ruler and a pair of dividers scaling the drawing up and creating the plans. The above was the result. The fore and aft guns turned and were controlled by one proportional channel for the aft guns and another for the fore guns. The guns were turned by a custom made servo that gave the right traverse speed and rotational angle.

The searchlights lit, the bridge lights lit and the the signalling lamp even flashed out "This is KMS Bismarck" in proper Morse code.

 
This is a close up view of the top. Each little boat (and the plane) was hand made from solid balsa wood, as were the small guns. The hand rails were pins stuck into the wood with black cotton tied between them then the lot painted black.
The photograph above shows the computer that ran the ship. The servo to the right controls a wiper arm that rests on a crude PCB. The wiper and the PCB lands connect to an input/output port on the computer. On the transmitter there were 8 buttons arranged 1 group of 3 and 1 group of 5. The group of 3 buttons selected which 5 of 15 functions would correspond to the group of 5 buttons. A selection was made when the wiper rested on a land for more than one second. The buttons in the transmitter were single pole changeover and had resistors connected to them so that when a button was pushed the servo moved to a given position. In the Nautilus the servo will be done away with and the processor will use the signal directly to determine what function is to be performed (although I will actually be transmitting 2 bytes of data rather than PWM for channels 6 and 7.

The picture above shows a close up of the main computer components. The CPU is a Zilog Z80 running at 2MHz. The Nautilus will use an Atmel AVR running at 8MHz. The Z80 required a bucket load of support chips (address decoders, RAM, EPROM and I/O). The AVR has it all built in. The Z80 needed a couple of hundred milliamps to run, the Atmel requires 2mA. The Atmel is also flash programmable meaning easy upgrade, it can even be reprogrammed in situ.

The CPU above used 48k of EPROM and 8k of RAM. The EPROM held the program and about 4 seconds worth of sampled sound from speech clips to gun sounds. There were ack-ack type gun sounds and main gun type sounds. By adjusting the playback speed from EPROM to a Digital to Analogue convertor the pitch of the gun sound could be controlled and the gun made to sound big or small. Most of the gun sounds came from one sample that was either chained at higher pitch (ack-ack) single (smaller guns) or single low pitch (main guns). The speech was recorded speeded up so that many words would fit the valuable few seconds of sample space then strung together by the processor to create sentences. The speech was slowed down on playback to attain a normal pitch. All in all I was able to turn the 4 seconds of sample space into over 30 seconds worth of speech and gun sounds. Even to a klaxon sound as well.

TOOLS.
BASIC CONSTRUCTION.
BASIC CONSTRUCTION PART II.
BASIC CONSTRUCTION PART III.
BASIC CONSTRUCTION PART IV.
ELECTRONICS.
DIVING PLANES.
PROPULSION.
BALLAST SYSTEM.
MODIFICATIONS.

LINKS to other sites of interest.

E-mail me: vikkiford001@aol.com