What is the downside to digital servos, I've heard they reduce battery life, but by how much? Are there any other issues, what is the upside?

Thanks for looking, I found what I needed thru Google, guess I should have done that first, before posting.

With digital servos you must make sure they get enogh juice or else the receiver starts going bazerk! Happend to me. Otherwise they are fantastic and can be programed and they give you real time stick to servo movement. Also a tad more dollars

Very simply I thought the main difference was that they are faster and have more torque than a comparable weight and sized analogue servo. That's the pro, now the con. They have a bigger Amp apetite! so require more expensive batteries, apart from a micro processor in the digital they are identical!

I don't agree with everything you have said,servos come with different specs hence different model # you need to pick the slowest one fast servos make the boat twitchy unless you have an expensive radio that has servo speed in the programming menu so you can slow it down,in fact i personally feel most servos are too fast for a boat not that i have done a whole ton of research on what is available,as for expensive batteries a 2s 1000mah lipo from Hobby King is less than $10 which can charge faster deliver a higher and more stable voltage because of it's very low internal resistance and weigh half as much, making a RMG winch quite a bit faster.

I run a 5646 on sheets and a 5086 tiller in my Vicky and 5245 on sheets and 5065 tiller in both my micro magics.

"Too fast" is not a valid argument against digital servos. Set your exponential to -50% and enjoy!

As for current draw, I sail 10+hrs on 2s2p 350mAh LiPo in the Vic and the same on 2s in the micro (through 6v regulators).

Digital is fantastic. The resolution and holding power are in another realm, compared to analog. 10000% worth it.

Originally Posted by northernmike

I run a 5646 on sheets and a 5086 tiller in my Vicky and 5245 on sheets and 5065 tiller in both my micro magics.

"Too fast" is not a valid argument against digital servos. Set your exponential to -50% and enjoy!

As for current draw, I sail 10+hrs on 2s2p 350mAh LiPo in the Vic and the same on 2s in the micro (through 6v regulators).

Digital is fantastic. The resolution and holding power are in another realm, compared to analog. 10000% worth it.

Using Expo will only soften the servo reaction in the center eventually the servo will catch up with the joystick therefore only delaying the movement,servo speed is what it says it is,it is a programable speed from beginning to end of the arc,so it creates a completely different feel from your joystick imput.Downside radios that have this feature are approaching high end.

With Hitec digitals, a $20 programmer and a PC with a cable allow you to program resolution, speed, rotation, etc. The power and lighter weight of digitals is a great combination in my opinion.....and I haven't noticed any excessive battery drain with mine.

Kevin
Canterbury J #551

Originally Posted by The Tug

Using Expo will only soften the servo reaction in the center eventually the servo will catch up with the joystick therefore only delaying the movement,servo speed is what it says it is,it is a programable speed from beginning to end of the arc,so it creates a completely different feel from your joystick imput.Downside radios that have this feature are approaching high end.

For our purposes here, expo doesn't "delay" the servo's movement... It creates a wide band of fine control in the center of stick travel.

It IS a "different feel" ... a BETTER one!

I, for one, do not like servos I have to wait for.

I set my dual rate switch to toggle my expo curve between what I call "upwind" and "downwind" settings:

- A wide center for upwind, making fine pointing adjustments easy: the risk of over-steering is greatly reduced

- A more linear response for downwind, for more agressive and faster maneuvering

(I set the up position for upwind, the down for downwind... easy on the brain)


I suppose if you really found digitals too twitchy, you could add some stick extensions to your Tx.

Maybe I've just got steady hands.

My Tx is an old Futaba T7C converted to 2.4 - not very expensive at all!

Cheap old stuff works great too, not knocking it, but try a boat with modern controls and see what you think.

That would be a brilliant solution for most with cheap to middle class radios.I use a Futaba S 9070 s bus because it's the only servo i'v seen thats rated from 4.8-7.4 volts and weighs 30g let alone it's very fast powerful and accurate however it's size is unique bigger than a mini and smaller than a standard.I use Hitec a Aurora 9 radio so i have all that in the Tx , the Rx can run 2s lipo no problem on the servo rail and that's not for everybody.I used to use expo until i discover'd servo speed,have you all ever seen a skipper on the helm of anything from a dingy to a 80' maxi jammin the helm as a servo can.

Somehow i don't think you have sailed using programable servo speed,you don't have to wait on the servo you set it to the speed you like and is to your desire.I can assure you i know what D/R and expo do i still own my trusted Optic 6,servo speed is another ball game.I hope my right thumb is not getting parkingsons as i'm plannin to use it shortly for whatever reasons i forget.
At least i am I and not My lol.

I just can't wrap my brain around slowing my servos down.

I can see a few problems this would be intended to solve...


1. I am thinking too quickly and make a dumb move.

- A slower servo won't get to the mistake before I have time to correct it, and therefore I might cover my arse. Solution: don't make dumb moves!

2. I am moving too quickly.

- A slower servo will fix this, but what if I WANT to move quickly? Solution: move slow when I want, move fast when I want.

3. I'm thinking and moving at different speeds.

- See my dual-rate expo solution above.



You're right, though, I haven't tried slowing my servos down. Maybe yours are so fast that they need it?! That 9070 is sweet spec. Thanks for that...

Originally Posted by The Tug

have you ever seen a skipper on the helm of anything from a dingy to a 80' maxi jammin the helm as a servo can.

As a matter of fact, that would be me on my 5.5 meter cat.

Jamming rudders back and forth with tiller as quickly as possible will stop you within a boat length or two depending on speed. This is a very "basic" tactical tool to stop before crossing the line too early at the start - or for other (ahem) tactical conditions, where you want to stop quickly.

Just sayin' ...........

Dick for the boat guys sail a 50' cat that can do 20 plus K,in our sport the flow moves much slower over the appendages than a R/c aircraft hense expo and D/R,servo speed is the answer for us because we get the same feeling across the arc of movement and it's constant.I wonder who on here knows how to sail backwards,Dick is a Multihuller for i and i Stiletto 27 for fun and a Spronk 50 for traveling.

Originally Posted by The Tug

I wonder who on here knows how to sail backwards,

When I moved from a jib/main to mainsail-only cat, it was the first thing one learned - and quickly. You were always (in my fleets) considered to be kind of a "dork" if you used the gybe to change directions upwind. Thus, with main only, you learned to back up if you "blew" a tack. [tiller to leeward and main and traveler sheeted to windward s long as needed - in medium or light air, you could handhold main to weather, but in heavy air, having a traveler that sheeted to windward of centerline of cat was a big help]

Also, knowing how to "park" at the line or close to it was helpful, but hard to do on r/c boat unless you have a servo for mainsheet, a servo for traveler and a servo for rudders. [basically, mainsheet tight, traveler out to leeward, and tiller pushed over to leeward] Cat keeps moving forward into wind, then falls back off wind and follows stalled rudders backwards. Basically stays in one place with some drift to leeward. Nice to be able to "park" and stop trying to barge in at windward end of start line.

Biggest problem with non-multihull sailors is they get anxious and try to tack the boat quickly like a monohull which brings them to a sudden stop. A potential for being blown over backwards exists if caught at the right angle to wind and wind/wave conditions.

Unfortunately, the Stiletto is no longer in production, and I think the same holds true for Spronk. (I'm not into big-cat cruising - so not sure) Somehow, I can't get used to sailing on a big, cruising cat due to lack of "feel" - hard to describe.

Apologies for off-topic post.