Ultimate-Jets

Here is a new feature post on the BAT series new sticks.

They are so advanced that tey well deserve a long explanation with lots of pictures to illustrate the design.

I have had the chance to try these sticks on demonstration units at different fare and I can tell you thhat there is nothing else in the wolrd that compare to this in term of feeling, precision, feedback and ergonomics.

 

Lets see why.


The new sticks, feature full aluminium design with 9 precision ball bearings. Large contact surface were made with the transmitter to allow a perfect transmission of the efforts to the casing and a high rigidity of the assembly.

The position sensors are made with Hall effect sensors. The main benfits of this is that there is no contact on the stick position sensor thus no wear and a perfectly replicable result with no drift. The hall effect sensors feature 8096 steps which is way beyond any digital servo resolution.

One can see the sensor boards on the 2 following pictures:



This picture shows the large bronze/ aluminium ball that provides dust sealing at the base of the stick as well as surface contact for a good effort transfer. Additionally to this, a large aluminium plate connects the gimbals to the box ( in plexiglass here for a beter vision of the mechanism ).



The feedback ramp is the white nylon part showing on the following picture. An ball bearing roller provides the stick follow-up/ return on this part. One can see the tension spring on the next picture that keeps the roller pressed to the ramp. The tension is adjustable to a large ratio and will change the return effect/ ratchet effect of the ramp.



Feedback ramps are user replaceable and feature different shapes for different stick feeling:

The CH, CN and CS ramps are typically used for flight controls that require a return to center. CH has the stronger effect, while CN and CS have decreasing effects. Note that the roller tension on the ramp would provide additional centering feedback grades. This is a world premiere and a big difference compared to normal radio gimbals that provide the return feedback from the direct effect of a coil spring ( linear force ).

Here the return force is non linear and strong around the center ( good center feeling when having extra small control inputs around neutral with excellent precision ) while fading away around the extremes.

 

The CD ramp only has a center click and does not provide any return force.



The ST ramp provides the typical ratchet feeling.



The SL ramp is a neural ramp with no return and no center position.



Most normal radio gimbals provide the return feedback from the direct effect of a coil spring. This gives a linear feedback that is adjusted linearily by the tension of a spring.

Here the return force is logarithmic and strong around the center ( good center feeling when having extra small control inputs around neutral with excellent precision ) while fading away around the extremes. The return spring will adjust the feeling along the whole travel, while different shapes will give you the ability to choose from 3 different logarithmic response curves.

CH has the stronger response curve ( very high centering force, fast fading away ), while CN and CS have decreasing effects. Note that the roller tension on the ramp would provide additional centering feedback grades, thus enabling you to modulate the logarithmic response between the 3 different shapes..










Another world premiere is the MA/ MB ratchet. It provides the effect of a normal ratchetwith 75% of the standard deflection. However the bottom 25% will act on another channel with feedback force. A proximity switch provides the end of ratchet detection ( secondary ramp as shown on the diagram ). This is extremely important to avoid shutting down the engine while moving on the non ratchet ramp.
I see a fantastic potential for this as a speed brake function. You could extend the speed brakes in flight without having to reach another switch.
This can also be used for the brakes on the ground but wwe are all used to reach the slider to activate the brakes. So I think that this function will be much nicer on the speed brakes...



Written by Olivier Nicolas — November 13, 2013

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