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[northwind]

Hi all

I've been looking around for a servo with a good rotating angle (throw / travel?), nowhere do they seem to quote the angles they travel to?

Is this a standard.. or something that's made up by each supplier. I ask as I did a trial run of my Paula III yesturday, and noticed that the rudders turning angle was very small and I would like to improve this.

Thanks

Daniel

[FullLeatherJacket]

Most servos turn about 45 degrees each side of neutral. This seems to be fine for most applications apart from sail winches. If you want more throw then either put the connecting rod into the servo output disc using a hole further from the centre, or use one closer to the centre of the tiller arm for the other end - or both.
If you want to increase the actual rotation of the servo then look here:
http://www.action-electronics.co.uk/pdfs/P96.pdf

Suit yourself - works for me.

FLJ

[OMK]

Oddly enough, I have a handful of various makes and models of servos on the bench as we speak. Each one tested against an accurate 1mS to 2mS pulse, each one monitored on the oscilloscope and each one all pretty much within the usual 90-deg throw. All well and good so far. But what a different picture when each servo is tested on 3 different makes of transmitter gimbals. You might be surprisd to learn that each gimbal is mechanically different in as far that they all produce different amounts of throw. The Futaba sticks give the most throw by far (approx' 80-degs), followed by a couple of ACTion specials (approx' 70-degs), and a couple of unknown sticks, giving just a measly 45-degs.
Further to the sound advice offered by FLJ, and if you're brave enough, you might also want to delve inside your Tx and hack/cut/file the mechanical end limits on each stick in order to squeeze out as much throw as possible.

[northwind]

Thanks for the replies, regarding the transmitter, I do wonder if this is to "blame" - I'm not getting anywhere near 45degrees, so I will investiate this this evening - Its a Spektrum DX5e (I'll compare to the DX6i I have to see if there any differences).

[OMK]

Somewhere in one of the Spektrum's menus will be the page where you can alter the amount of servo travel, usually given as a percentage. Check that your rudder channel is set for maximum.

[barriew]

Somewhere in one of the Spektrum's menus will be the page where you can alter the amount of servo travel, usually given as a percentage. Check that your rudder channel is set for maximum.

PMK

The DX5e doesn't have adjustable servo throw - the DX6i does - as I'm sure Northwind knows if he's got both. I have a DX5e with an AR500 Rx in a Deans Fireboat and haven't noticed a problem with turning circle.

Barrie

[OMK]

Ah, I stand corrected.
No experience with the DX5e - just assumed any computerised radio would have had adjustable throws as standard.

Tnx!

[Roger in France]

I guess it is all about servo arms and tiller arms and you need to alter the distance the links are from the fulcrum. In extreme cases it can be necessary to make a small extender for one or both arms. A five minute job with a pair of snips a file and a drill. I use brass strip, aluminium or a hard plastic.

Roger in France

[malcolmfrary]

When arranging differing lever lengths, avoid having the difference too great - I have seen cases where the servo arm, being considerably longer, pulled the tiller arm over centre, thus latching the rudder in "reverse".

[barriew]

Ah, I stand corrected.
No experience with the DX5e - just assumed any computerised radio would have had adjustable throws as standard.

Tnx!

The DX5e is not really a computerised radio - it uses digital trims, but has no display to indicate how much trim you have applied! The servo reverse switches are the usual (on non computer radios) switches. I am sure that there are some digital electronics controlled by a microprocessor some where in the set, but not in the human interface

Barrie

[OMK]

Ah, hear that, too. Tnx again.

'Twould be a shame to mess up that dinky radio. On reflection, if in Northwind's shoes, I'd steer clear of messing around with the gimbals and take the advice of the wiser ones. Like they say, you should be able to get all the travel you want just by messing around with the linkages.