OK,
Im thinking about buying/building my 2nd pattern plane sometime before next year.
I'd like some folks who have had some experience to tell me what the real flight advantages of digital servos are. I understand what a digital servo does, well let me say that I understand enough to know how they physically respond differently to air flow feedback than standard servos. But is it really that big of a difference in the air? Im not talking about electronics and power use, Im talking about how the plane responds to control inputs and what the judge will see differently because Im flying digital servos?

Do they really give a good pattern pilot a significant advantage? Or is it just a "bells and whistles" thing with just a minimal advantage?

I'm sure you'll draw a wide variety of many experts to provide dissertation on this topic.

I'll say this - there is a point, very definitely, where a pattern pilot can "tell" (feel) the difference between analog, non-coreless analogs, digitals, and coreless digitals. Each step provides a tighter "loop" between your eyes/fingers/plane.

And - each requires more meticulous setups of linkages, hookups, control surface deflections, servo mounting methods, and the expo or ATV.

The "judge" will only see a difference if you are able to respond more rapidly to a change in the airplane because you have the "better" servos. I tell people that when they are flying airplanes they have trimmed to a resolution where they can "feel" when a linkage gets a little slop, or the servo pot gets just a little hesitation at center, then they likely will benefit from "better" servos.

Of course, many will say to "buy the best you can afford", and relative to servos, I endorse that perspective. But whether a judge of YOUR flight will know whether you are using digitals or not, I have to say, I don't think so.

Well for me, with my low rate down to 23% the digitals are a lot more responsive than the analog coreless servos that I tried.

I have to agree with Bob, when flying the plane yourself, comparing a standard or any analog to a digital or coreless digital is a HUGE difference to me. I had to get use to the precise centering and very very fast speed. Particularly in precision manuevers they were much crisper and the 3D flying when burying the plane in hard manuevers the servos never run out of umph.

But dont you essentially x out the speed of the servo when you add in expo? I mean you get a really fast servo that runs at .09 and then you add 30-50% expo what are you gaining in the normal flight control range? Arent you giving that need for speed back to get a softer or slower response as the curve dictates? I mean the things you are looking for in a servo are response and reliability.


The only real advantage on paper I am seeing that digitals do that analogs cant do is
i.e... if you move the stick to say,, full up elevator sitting on the ground and you get 12 degrees of throw, when you get up in the air an analog servo may only actually be giving you 10 degrees because the air is pushing the servo back, so you push a littel more not even knowing you are having to add more input than you "should to get 12 degrees".
but your brain tells your hand to adjust to get the plane to do what you want it to do anyways,,

A digital in the same scenario adjusts the signal to overcome the feedback from the airflow and forces the servo to the exact position it want the servo to be in, but how in the world can you tell? I mean your hands arent going to be able to tell 1 or 2 degrees of difference in the stick input versus what you see the plane do.

So the analog sends a given amount of power and doesnt actually know what the servo position is, right?
And the digitals send out a given amount of power, get feedback of the actual postion of the spindle/servo arm and add more power to force the spindle/servo arm to the position it wants...

IMO RC flying is 95% visual, you have no other physical connection to the plane but sight, all your corrections are done by sight. The sound of the engine gives some information to make you feel secure but you react to what you see ..

When the plane is in the air, you dont know how much deflection the surface has, you only know what you see the plane do, so you give stick correction to make the plane in flight look and react the way you want it to.

I can see where you could see the difference of two identical planes set up identically with identical radio setups one with analog and one with digital. Just seems like if you wanted more response with less stick input you could just take expo out.

Im gonna have to eventually try it and see for myself, I can see it already. And as Bob said Im a sucker for the old addage of "you get what you pay for.

Sorry to ramble, just got me thinking.

Okay...I'll take a stab at some "actual" differences....[Here's the disclaimer - THIS IS *MY* OPINION, ONLY - Worth What You Pay]

1. Immediate full torque available when moving off of center. Makes the "small" corrections faster for me to pick up, fix, and hopefully *hide*
2. Holding power - throughout the range, there is no fade...on my snaps and stall turns, for example, they LOCK and HOLD; permitting me a much more positive entry and exit
3. Resolution - I am able to very precisely trim, using the lower trim authority settings....for example, a single "click" at the low authority can be SEEN to move the surface. It's subtle, but can be important.
4. Mixes - because of 1 - 3 above, any mixes needed are more consistent, precise, and more effective.

[Reread my disclaimer!]

If you fly a lot, and your plane is properly set up, you can tell. By a lot I mean at least a case a week, for instance. Winning? A lot? Chances are you could very easily umm...."feel the difference"....heh.

No, it holds position better, and one degree of travel on a clean pattern plane makes a HELL of a difference. Now granted, if you only fly say once a week or so, and you're geeking every manuever, then no you probably couldn't tell the difference. But when you're flying a lot and you are routinely going up against guys that are only seperated from you by a point or 2, then it can make all the difference in the world.

It's not something you can rationally explain, although I'm trying (from a strange angle, I know). but honestly you really just have to feel it, and it depends on a number of factors. For instance if you're linkages have play, then no you'd likely not feel it. if however they were totally tight with no slop and you swapped to digitals, chances are you'd feel it immediately, assuming you had a decent plane to begin with. Some designs it doesn't matter what you put in there, they fly like crap and hunt a lot.

Now the decision of whether or not they're worth the money? Totally an individual decision. I even put digitals on my fun flys. But I campaigned a pattern plane a couple of years ago with JR 7005s all the way around, and I won 8 out of 8 and a district championship. So, maybe I'm just muddying the waters more But if you don't think they're worth it, then they probably aren't (for you). And if you do, then they are DEFINITELY worth it. Is that clear as mud? Heh.

-Mike

Err, what bob said

-Mike

My contribution: As a relatively new pattern flyer in Intermediate class this year with my 1st 2 meter plane I have observed the following: Started and currently using JR 8101 on both ailerons, 4721's on the rudder and elevator.back in the early spring my plane really locked in like it was on rails, very stable in the roll axis, but as the year has progressed the plane seems to be constantly hunting for that groove and it's getting harder to keep the wings level in pull ups and loops. Is it that the servos are showing wear around center or is that my flying skills have progressed to the point that I am now able to define what is a locked in feel. From discuusions with my flying friends probably both. With experience I am becoming more in tune with the minute feel of the plane and demand more precision eventhough the servos still have a tight feel and seem as strong around center as ever. SO, I plan to make the switch to digi's soon and see if that helps my flying progress to the next level.

Mike A.[8D]

Good comments.

I really dont have practical experience so Im just telling you what I think. What did hit home was that in situations where a few points matter it could be the difference. All 4 of my pattern buddies fly in advanced and several times I have seen the top 3-5 guys all in advanced within 10 points of one another.

Im just getting started in intermediate so I am still learning to "feel" the plane. Hopefully the next plane will carry me through advanced, so Im sure I will go digital since everyone I know says it matters and Im sure it does.

What little bit I've seen and know about you Bob I get the sense that you wont waste money on bells and whistles unless they are really useful. From what I have seen you kick butt with very practical gear. And I mean that in a good way, that in itself is enough to make me want to give it a go when the time comes.

Im still waiting to see if there is anyone who says digitals dont matter on a correctly built and trimmed plane though. Id like to see if there is 1 person who cant see the value and can compete without digital servos.

My opinion is worth the same as aerobob - but here goes:
I always want something that is better than I am. That goes for airplane, servos, etc. Why? Because as you improve your flying, you will never be limited by your equiptment. You may not "feel" the difference between analog and digital today - but you will as you improve your skills. Then you can take advantage of the digital's superior holding power and accuracy. You will also reach that point faster with superior equiptment.
Do you "need" digitals? No.
Will they make you a better pattern flyer faster? Yes.

I'll preface my love for digitals by saying that you'll notice the difference a lot easier on a plane set up with 3d linkages.
I'm relatively new to pattern, but I've been playing around with 3d since it was first done at the TOC.
If you have 3d linkage geometry the difference is HUGE. Especially on 25% and larger IMAC.
I switched from JR 4721's (not at all shabby) to a mix of 8411's and assorted cheaper Hitecs Digis and my 80" Sukhoi felt like an entirely different plane. It felt like the C.G. was another 10% back from a response standpoint. I more than doubled the expo setting and found that "locked on" feel the plane had been lacking, especially in high speed yaw. (knife edge and point rolls)
On a pattern only ship with minimal throws the difference will be more subtle, How much is it worth to you?
Try the digis and if you decide they aren't worth it, the resale values are amazing.