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Throttle trim tab - never used it - why would you?

What's the point of the throttle trim tab? (Never used it).

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Engine Doctor18/10/2020 10:32:29
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Posted by Peter Miller on 18/10/2020 08:20:56:

OH Yes! My first 4 channel set. McGregor. Two sticks, four trim levers and an on/off switch and a replacement servo cost a good proportion of a weeks pay. You had to know how to set the controls up and how to change the throws on the field after the first flights.

Going back even further, RCS Guidance System. A switch and a button. You haven't lived until you know what we used to have to do.

I can go back even further. ECC Telecommander. Two 45 volt hearing aid batteries, one 1 1/2 volt grid bias battery. four pencells for the actuator.

Tune the receiver with a milliameter, set the sensitivity with the milliameter. Start the engine, the relay would chatter and the escapement would chatter and all the turns come off the rubber drive to the escapement. Start all over again. I never did get a flight out of that. And it cost £10. in 1954. That was the best part of a weeks pay. To give a comparison My Raleigh Trent Sports bike (top of the line) cost £20

Now we have more gubbins on our Txs than we will ever use.

As for the throttle trim. Engines need fine trim due to weather variations and getting the tickover right and stopping the engine.

My first radio set back in 1958 was a 27 met carrier wave.The servo I had was a trunion type driven by a " Mighty Midget " motor and a galloping ghost switch box ,separate from the Tx was used to set the pulse. Throttle was an clockwork escapment .The Tx was a Tri-ang with a 10 ft plug together aerial like a tank aerial. The Rx was built by s friends dad from the RCM&E magazine , remember the small mags that cost 1 shilling and threepence ? As you say had to be tuned before every flight or sailing and hopefully stayed in tune for the duration ? The other annoying thing with them was that only one set could be used in the area , no crystals then.and if I messed about with it in the evening at home it would wipe out reception of any television near by. I never used it in aircraft as you couldn't fly them on local commons so it was used in boats on Clapham Common boat pond. Then came the Rep tritone radio with reeds that still had to be tuned before each use. Happy days

Edited By Engine Doctor on 18/10/2020 10:33:43

Bob Cotsford18/10/2020 11:00:13
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Posted by Engine Doctor on 18/10/2020 10:32:29:The other annoying thing with them was that only one set could be used in the area , no crystals then.and if I messed about with it in the evening at home it would wipe out reception of any television near by. I never used it in aircraft as you couldn't fly them on local commons so it was used in boats on Clapham Common boat pond. Then came the Rep tritone radio with reeds that still had to be tuned before each use. Happy days

Edited By Engine Doctor on 18/10/2020 10:33:43

Aah! Memories of annoying my big sister by blipping the CW button when she was watching 'Ready, Steady Go!' on TV teeth 2

David Hall 918/10/2020 11:20:04
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My F5J flying would be much more difficult without the throttle trim.

The trim on my more recent radios (Taranis on OpenTx) is actually a separate slider control that happens to be mixed with the stick function to provide a trim control.

As I don't use the trim on the throttle control for the motor, I have switched off that function. This gives me a slider control in a very good position on my Q7x (this Tx has no other sliders).

In my gliders, this slider is set up to adjustable the motor throttle to elevator mix when in "launch" mode (they tend to try to loop without some down elevator on high power), It is disabled, along with the throttle, in "glide" mode and in "landing" mode, it becomes the flap to elevator gain mix control (throttle stick becomes the flap control).

For me, it works so well that when I set up my X9D, I kept the same layout, even though the X9D has sliders.

Phil Green18/10/2020 14:44:52
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Posted by Peter Miller on 18/10/2020 08:20:56:

Going back even further, RCS Guidance System. A switch and a button. You haven't lived until you know what we used to have to do.

...and can still do, if you enjoy a bit of 'real retro'... laugh

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