by Tore Loodin

Here I will try to describe how I made my own "Persuader" for Cox ·049 engines and the like.

Click this thumbnail for a full-screen view of the drawing.

I bought a standard Mabuchi 450 motor from a warehouse for around £3. A large screw-on brass collar was fitted to the shaft - you can probably get this from an iron merchant. As a propeller interface, I used a cone-shaped door-stopper - you know, the things screwed into the floor behind doors. This I shaped with a knife to fit the propeller hub. Using silicone as an adhesive (the stuff you use as a bathroom sealant), I glued it to the screwed-on collar. After 24 hours hardening, the stop won't come loose. I siliconed a push-button connector to the motor housing of the Mabuchi.

To join the connector, engine poles and the battery, I used black and red silicone laboratory cables which are much more pliable and which do not get stiff in sub-zero weather. One end of a short length of the red cable was soldered to the + (positive) pole of the motor and the other screwed to one terminal on the push-button connector. A suitable length of the red cable - lets say 50 cm (18") - was screwed to the other terminal of the push-button connector. Now take a length of the black cable and solder one end to the other motor terminal and make this cable a little shorter than the red cable, to terminate at the same distance from the motor as the red cable. 

Now you have to connect the red and black cable ends to a male connector. I use gold-plated circuit-card connectors which electronics firms sell in strips of male-pin contacts and female socket contacts. Break off a pair of three-pin/three-socket contacts and solder the red and black cables to the the three-pinner with the centre pin unused to avoid shortage. Remember to first put shrimp insulators to the cables. As a matter of fact, I use these kind of connectors for all of my electronic equipment - they are much cheaper than Sanwa or Futaba connectors!

Now take a pack of 1200 mAH cells and solder the red and black cables to its plus and minus terminals, soldering the other end of the cables to the female socket connector as you have just learned - one pin between and shrimp tubes on to avoid holy smoke! It is probably easier to connect up the female socket first, then solder the leads to the battery pack. Check again that the red lead goes to the plus pole and the black lead to the minus pole. After that is done, I usually paint the plus side of the connectors with a red dot.

Now it's time to test the Loodliner Persuader. Heck! The motor runs in an anti-clockwise direction! If it does, cool down and switch the cables on the motor terminals.

For a handle,I use a cardboard tube from an empty toilet roll, whose diameter happens to fit the motor case.

Then you only have to use a good glowdriver to get the Cox started. I use an home-made pulsing device from a 12V 3-amp sealed acid battery. When the plug is wet, the driver is chirping more current and if dry, less current, thus saving the plug. Test on a dismantled glow head first! Set the pulser on low and slowly strengthen the current until the glow thread glows cherry red. Remember that different plugs than Cox plugs may need different current, so test always so as not to be sorry!

Voila! An inexpensive Persuader for the nasty little critter!

ModelFlight disclaimer. Although I have every confidence in Tore's competence, for my own protection I have to state that I cannot take any responsibility for the reliability and electrical/electronic safety of this device. Please direct any questions to Tore himself at tloodin@hotmail.com who, I am sure, will be happy to respond.

Clarence Ragland (USA) came in with some views on #19.

The debate continues with some comments from TOM WATSON, from Australia.

First of all, some of these principles should have been taught right from the start, i.e., flying opposite direction circuits and figure eights should be taught right from the start. This will take care of most of the orientation problems. As you know, it takes a LOT of practice, and I mean disciplined practice. 

Unfortunately, most people tend to "fly around" and do basic aerobatics once they can take off and land without breaking the model. I did it for many years until I found myself at a strange field and almost lost it because I was not sure of where I was. I know that practice is boring at times, but when you can fly lots of touch-and-go's anytime you like and in any weather, it is very satisfying.

In Australia we have a system of "Wings" awards. There are three levels (Bronze, Silver and Gold) and each club has several "inspectors", for want of a better term, who will test you for the awards. You are not allowed to fly unaided until you have the bronze wings. The awards are voluntary after the bronze, but most contests require gold wing standard to fly in public.

It takes a special person to instruct - I don't have the patience - and we should encourage anyone who is good at it. You get to fly lots of other people's planes!

On the question of how do you remember which way to control when the model is coming towards you, I always put myself in the airplane. It took some practice but is now automatic. I still can't do it with the helicopter in a hover!

Tom says he will try and get a copy of the Awards manoeuvres for us to see. They sound rather similar to the British Model Flying Association 'A' and 'B' certificates and I guess other national associations also have their equivalent.

The favourite adage for controlling nose-in flight seems to be "prop up the wing that is low" where you think of the stick on your transmitter as a supporting pole; if you want to push the left wing up, move the stick to the right and vice versa.

This nasty, black, solidified mess is the top end of my NiCad remote Glo Starter! I went to my flight box to use the starter and found the small crocodile clip on the wire of another starter had become jammed in the top of the Glo Starter, shorting across the two poles and thus burning it out completely. The insulating material surrounding the central contact had been burned to a frazzle for as long as the battery lasted, I guess. I do not know exactly when it had occurred - sometime after I had packed everything away from the previous use of the flight box, so this thing had been cooking away inside the closed flight box which also contains my fuel bottle! A piece of foam packing in the compartment was also charred, so it seems I was lucky that my flight box - and the garden shed in which it is kept, along with my models and all my modelling and d.i.y tools - had not gone up in flames. Now I come to think of it, I actually noticed a slightly acrid smell like hot bakelite both in my car and the shed some time previously but simply could not think where it might be coming from! I've replaced the starter and note that the new one is supplied with a protective cap which I shall be careful to use when parking it!