Nitro throttle set up

[Adsmalan]

I am new to nitro and I am struggling a little setting up the throttle. I had a plank many years ago and the radio had an analogue throttle trim. My current radio has a digital trim, how does everyone set their throttle up using the digital trim? I did a search online and ended up more confused and most of this info is probably outdated.

[paul35]

I leave my throttle trim at 0 or centre position and use throttle cut to stop the engine, what radio you got?

[Adsmalan]

My radio is a DSX9. With your trim at 0 centre and throttle low is your throttle barrel completely closed? If so I assume you adjust idle by applying positive trim i.e. above 0 centre?

[DanWright]

Ive just learnt this myself so ill try and help, but someone please say if im wrong.
What you need to do is set your servo horn and throttle lever parallel to each other. Make sure when you do this that your sub trims are on zero (try and get as close as you can mechanically, then use your radio for final tweaks)
once you've got them parallel, you need to make sure when your throttle stick is at half way on your tx the carb on the engine should be open half way. If its not then try adjusting the length of the control rod until you get to half way. now you'll probably need to adjust end points in your transmitter. If its been set up correctly you end points will be similar each side. To adjust the idle, Just pop the trim up a little. That's what I do
What engine are you using?

[paul35]

No when the throttle stick is fully down engine is at tick over, I set my tick over using sub trim, that way it doesn't alter the your pitch trim

[Steve]

Which engine?

[trexsteve700]

The trim tab on your tx should only alter the throttle and not the pitch.

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[bolders]

No when the throttle stick is fully down engine is at tick over, I set my tick over using sub trim, that way it doesn't alter the your pitch trim

Don't know if the DSX9 is the same but on my DX6i the trim only effects the throttle channel at the low end. It has no effect on throttle at high stick or on the pitch. Of course this may be different on the more advanced radios.

As mentioned above it would be useful to know what engine you are running as the tick over point can vary. For example on the OS 50 the throttle is only just open to get tickover whereas my Rossi57 engine with 2 needle carb is set to almost halfway between the fully closed and mid throttle markings.

However as Dan mentioned the best place to start is to set your carb at mid position when at half throttle on your tx (zero trim) and ensure that both servo arm and throttle arm are 90 degrees to the throttle linkage. you can then adjust the max and min throttle positions by adjusting the throttle channel endpoints on your tx. Ideally though you want your endpoints to be as close to 100 as possible which you can adjust by moving the ball position on your servo arm and/or carb throttle arm.

Also make sure you are using a linear throttle curve for setup i.e. 0-25-50-75-100

[trexsteve700]

If you set your idle using endpoints can you still drive the servo further to shut the engine off ?

Ive never tried it using endpoints

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[paul35]

I'm using futaba 10c and now i'm not sure if it alters the pitch or not will have a look

[Steve]

No, the DSX9 has a dedicated throttle cut function on the back right spring loaded switch.

You can set the endpoints to 100% each way for full chat and tickover throttle for flying, and then use the throttle cut function to enter a negative value (usually about -15% does it) to cut the engine. The throttle cut only works when the collective stick is low.

[bolders]

If you set your idle using endpoints can you still drive the servo further to shut the engine off ?

Ive never tried it using endpoints

sent by me from my phone

Again I can only comment on the DX6i but when you have your endpoints set to 100 the throttle cut-off will drive the servo to 125 (max on DX6i).

If you go above 100 on your endpoints the throttle cut off still only drives to 125 (again due to max travel)

If you go below 100 on your low end point the throttle cut off value also reduces - it probably runs at the same ratio though i.e. 25% more than your end point. So if you set endpoint to 80 then throttle cut-off should drive to 100. If I remember I will check this next time I hav got hold of my radio.

[trexsteve700]

sent by me from my phone

[trexsteve700]

No, the DSX9 has a dedicated throttle cut function on the back right spring loaded switch.

You can set the endpoints to 100% each way for full chat and tickover throttle for flying, and then use the throttle cut function to enter a negative value (usually about -15% does it) to cut the engine. The throttle cut only works when the collective stick is low.

Thats the same as my A9 but wasnt sure if you could drive the servo past the endpoint

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[Adsmalan]

Thanks for the replies so far. The engine is an Align/O.S 50. The DSX 9 has a feature on the radio where you can set the trainer switch as an engine cut off or you can set a trim memory on the throttle. This allows the previous trim setting to be restored with one click(beep) of the trim lever. I would however prefer to use both of these at the same time as it would make things a little easier but you can only use one or the other. The main advice I have had is to set the trim lever to the bottom then set the throttle mechanically as described. Idle is then set by moving the trim upwards and engine shutoff by moving the trim to the bottom but with digital trim this is relatively slow compared to analogue trim hence my original post.