German G7A 20th scale model torpedo more info

1/20th scale Model Torpedo - German G7A - more info

The ESC (speed controller board) may be one of a number of different types.

The two, speed control, magnetic reed switches are US made and good quality "Littlefuse" versions and they are reliable and (magnetically) sensitive.

The finished 20th scale German G7A WW2 torpedo, complete with balancing weights and dual on/off switches. There are a couple of weights in the back section also. The weights are only on the bottom side of the board to prevent body roll as the torpedo travels. The whole finished 20th scale G7A torpedo weighs around 120 Grams and when it finishes it's run, it floats with the nose only out of the water. The two battery cells are rated at 270mAH.

Production torpedo's are only available un-painted, the picture above just shows the carbon fibre mid body painted silver.

1/20th scale Torpedo Operation - all 20th scale models

The torpedo has a battery charging socket behind the batteries, this is connected directly to the two 270mAH Lipo, single cell batteries and should be fully charged, as soon as received, with a good quality Lipo charger at no more than 300mA charge current and set for 2 cells. a bare ended 3 wire charging cable is supplied with each torpedo, the red wire is positive (+) , the yellow wire is negative (-) with a central black wire for the central battery connection for use with a balance charger, these bare wire ends will need to be soldered to an appropriate connector to suit your charger. The torpedo should be charged with the on/off switches in the off position.

There is a main on/off switch mounted in front of the motor and a further on/off micro switch mounted behind the motor which is activated when the front body is installed, the main switch is shown in the picture above in the "off" position. When switched on and the forward body is installed the speed controller will make a beeping sound through the motor windings, however as neither of the reed switches are yet close to a magnet the receiver emulator circuit, which is built on to the main board, will be set at high speed so the ESC will prevent the motor from starting, for safety reasons.

Placing a magnet near either of the reed switches (located between the motor and the gearbox), with its N/S magnetic orientation in line with the torpedo body, will cause the receiver emulator to go to the "motor off" or "zero speed" position and the ESC will make some more noises through the motor. The torpedo is now "armed" and when the torpedo is moved away from the magnet, the motor will start. Be careful of the propellers, they are metal and they are sharp.

A small smear of vaseline or a layer of PTFE plumbing tape or similar should be applied around the joint between the front and rear bodies to keep water out (after final painting of course).

The 20th scale torpedo's are fitted with a speed control potentiometer located between the motor and gearbox which adjusts the motor and therefore the running speed.

The torpedo can be propelled out of a torpedo tube by air pressure or water pressure, the arming magnet(s) need to be mounted on the outside of the (non magnetic) torpedo tube and aligned with the internal reed switches inside the torpedo and again with its N/S magnetic orientation in line with the torpedo body.

The torpedo has a counter rotating gearbox and twin counter rotating propellers, so that it runs straight and true. Once launched it will travel in a straight line, just below the water until the battery reaches it's cutoff voltage, at which point it will slow down and stop. It will hang, props down, in the water with the nose slightly above the waterline and will need to be retrieved.

If you intend using these torpedo's in a large lake, or where you can't easily retrieve them from all around, you may need some sort of paddle boat and a net at the ready, for the retrieval operation.

1/20th scale German G7A Torpedo Specification

Overall Length - 358mm - 14.1"

Overall Diameter - 26.67 - 1.05"

Overall Weight - 120 Grams - 4.23 ounces

Run Time - TBD

Maximum Running Speed - TBD - (adjustable) bear in mind that these may hurt and may cause injury if they hit you. Do not use near swimmers or animals.

The package

I send all packages with tracking so that they don't get lost. Often packages are held at the customer's local Post Office as they can be too large for the customers mailbox, so if it has been a week or more since I notified you about shipment, please check with your Post Office. If I receive an attempted delivery message I will email you. If you don't pick it up after a couple of attempted deliveries it will likely get returned to us.

All packages are marked with the international Harmonised code for Reduced Scale Model Kits - HS950320.

The total price includes tracked parcel postage to most places in Australia, New Zealand, Canada, the US, UK or Europe.

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