Ford Trimotor AT5 (oz11372)

About this Plan

Ford Trimotor AT5 Tin Goose. Radio control stand off scale model for electric power.

Note this design was previously published in Radio Modeller February 1978, and that planfile is listed as Ford Trimotor (oz8706). The two drawings are very similar, although the plan layout differs, and the text on this plan here is much clearer, easier to read.

The text of both articles is the same, although the photographs used differ.

Quote: "FLYING: Make sure that the model balances at the point shown on the plan, and that all controls are neutral. It is best to set the ailerons up about 1/16 in, as this gives the effect of washout, and can help to delay tip stall. Sight the model from the tail to check for warps, and charge the power pack.

If you have a good smooth surface, it is best to allow the model to take off; alternatively, you can have a reliable helper hand-launch it for you. Choose a calm day for your first flights, and since the battery pack will not be at its best in the beginning, do not attempt to climb initially, but concentrate on straight and level flight. As the battery improves, you will begin to be familiar with the capabilities of your model.

A word of warning: If at some time you choose to fly in windy conditions, do not turn sharply out of the wind as it is possible that, due to inertia, it might lose flying speed, an incipient spin could develop, and you would take it home in a plastic bag! Treat it sensibly, and you will he rewarded with some really stately flying, just like the real thing! GOOD LUCK!

CHARGING NOTES: Any commercially available battery pack should be charged according to the manufacturer's and/ or distributor's instructions. The following information is intended for those who will buy their cells separately, and make up their own packs. If the cells have no tags on which to solder, do use a large 65-watt (or more) soldering iron, and do not keep the iron on the cell for more than a second, or you could damage it.

Ideally, have the battery pack completely discharged before charging, so that you are sure how much charge it can take. This is important since, although these cells can be charged in as little as 15 minutes' time, particular attention should be paid to time and current measurement. In fact, to take account of possible ammeter error, only 90 percent of the cell's capacity should be used in calculating charge times.

EXAMPLE: Suppose we want to charge a 2.0Ah cell in 30 minutes. 90 percent of 2.0Ah = 2.0 x 90/ 100 = 1.8Ah. Current needed = 1.8Ah x 2 = 3.6 amps for 30 minutes. Special cycling equipment now available is a great help in the proper care of nicads. However, if you take the necessary care, then you can charge the way I do and, charged carefully in the proper way, the cells will last for a long time, and could see out several models!

To charge the 9-cell, 2.0Ah pack in 30 minutes will require a minimum of 16 to 18 volts. It is essential to have a good ammeter in the circuit that will read correctly to 0.1 amps (eg: 100 milliamps), with a full scale of 5 amps or more. I make all my connections with small crocodile clips, and use a short piece of electric fire element as a resistance to control the current to the required amount. I usually charge at 4 amps for 25 minutes; this seems to work OK. Whatever you do, use the time / current calculations!

Don't forget it's on charge while watching your pal's new model bombing round the sky - you could ruin a good set of nicads!"

Direct submission to Outerzone.

Supplementary file notes

Article.

Corrections?

Did we get something wrong with these details about this plan (especially the datafile)? That happens sometimes. You can help us fix it.
Add a correction