Hi people, I'm looking for thoughts or opinions on the best spirit device to buy.

The heli
Ark 450
SD108P micro digital servos (very middle of the road digitals but quick enough)
Flight weight 587 - 657 grams (I'd like to keep this below 620 grams if I can)

Tx
Radio is a 'generic' computer system (Radiolink AT10 with telemetry)

I want to keep the flight weight as low as possible and the Arks air frame is quite small, the 450 is more of a hopped up 400. The mount space for the tail gyro is not huge but is big enough for a μSpirit or Spirit.
I'm liking the idea of saving 13g by using the μSpirit.
Anyone have any thoughts on this, what might be the downside of the μSpirit as the specifications look very similar.

For this class heli it should be definitively the Spirit unit.
You can save lets say 5 grams by choosing a light connectors, shortening cables, selecting a different blades (this could give you much more), different canopy or selecting a light battery and ESC. In ESC you can save even 30 grams just by selecting a different brand, while amperage rating could be same.

The uSpirit would work, but you will need 4x JST-Servo adaptors for your servos. uSpirit is recommended for helicopters up to 250 class.

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Spirit System developer

Thanks for the response, I thought that would be the answer but thought that I'd better ask.
I had better get an order in

It arrived today, very quick service, thanks
Now all I need to do is build the heli.
I've decided to hack the thing and go FBL which isn't an off the shelf solution, all I need is for the new head unit and some 5mm stainless so I can make a custom shaft ... what can possibly go wrong

Great! It should always work somehow. You will just need a good geometry to make it work well.

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Spirit System developer

As people might know the designer of the ARK heli range originally designed the early TREX models, so there are many parts that are interchangable on the ARK 450's.
I've just made a direct swap out from the original flybar head to a FBL which fitted perfectly even the connecter rods were the within a few mm's of being the right length. The head lines up as it should so the head geometry is looking good. I just need to decide if I want to use the snappier FB or get some FBLs blades, I'll probably fly the FBLs first.

I've found the specs for the servos, 1520µs / 300hz with a dead band of 1µs.
The set up wizard for the spirit puts the servo specific page after the swash has been levelled. That seems to be wrong as the unit is not going to drive the servos properly with the default settings it has.
If I start the PC interface and set the servo specs then save this setting first THEN start the wizard will the servo settings be held??

I am little bit confused with this:


because first you are configuring the servo specs - Step 3 and then you are levelling the swashplate - Step 7.
So what you have written does not fit or I dont understand you fully.

If you will proceed according the setup wizard step by step, then it is the right way.


Settings in the Step 2 and 3 might be overwritten by you, because at this moment unit is not communicating with the software. But after step 3 all the settings will be unchanged if you will not change them in the wizard.

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Spirit System developer

All sorted and working.
The FBL head was so easy to set up and after a little playing the Spirit unit was equally simple (just me being a bit stupid!).
Tail hold is very good, nice solid head hold.