PlaneHeli

What is the difference between Digital sevos eg Futaba S3151, and analog eg Futaba S3001 servos.

I have some S3001 in my heli. They seem to work OK.
What are the advantages of the digital servos over the analog.

Also, completely off subject, I notice LOL used alot on this forum, what does that stand for?

Cal 83

Gorgok

lol = laugh out loud
rofl = rolling on [the] floor laughing

Its just one of the hundreds of internet slang words that exist now... Most originally come from abbreviations such as the above but have mutated... Like this pic here, the rofl copter...



As for the servos, i understand Digital servos center much better, and are more accurate. Thats because of the differences in Digital and Analog singnals.

BarracudaHockey

My Feedback: (11)

http://www.futaba-rc.com/servos/digitalservos.html

There's a pdf on there that talks about how digitals work and what the difference is.

The 3151's aren't a great upgrade over decent ball bearing servos. The 9252's would make you think you had a different heli but they are 70 dollars us a piece.

credence

My Feedback: (2)

Hahaha, that image is great!

Motions

I use S3050 for cyclic and collective in my R50. They are great servos for the price. Really good torque and good speed.

walter2323

Do digital servos have safety logic in them that stops them from trying to turn to some impossible position in response to interference? I seem to be prone to interference in the places I turn on my heli, and I've already destroyed a servo by having it turn too far. Seems like a simple bit of logic in the servo itself would be enough to avoid that problem.

PlaneHeli

Barracuda,

Thanks, that explains it. I had done search but just came up with technical info that didnt really explain the benfits of each.

I notice on the web my Futaba radio should have come with 3151 servos, (Bought it in Asia though) but it may have come with 3001, will have to check when I get home, so was just wondering if id been ripped off, and should I upgrade the servos at some time to better digital servos.

Michael211

My Feedback: (1)

Yes, you should consider upgrading to good quality digital servos for the heli... ball bearing and coreless would be the best. Though you didn't specify what size heli you have....

Benefits of digital coreless BB servos are that they center better, respond to inputs faster, have more torque and aren't as prone to failure in high stress/vibration applications.

From all I've read over the past year or so, standard airplane servos (S3003, S3004, etc.) aren't designed for the stresses that a heli puts on them and will fail prematurely. This goes double for the larger 50, 60 and 90 sized nitro helis! If you're flying something smaller in the 30 sized range then you might be ok for a long time with your S3001's though.

Last I checked on Tower Hobbies the Futaba S9252 servos cost about $79 apiece, but over the last 2 months I've been able to win 4 of these servos for about $45 each on Ebay.... it just takes a little time and patience to get them from Ebay auctions of course.

Regards and best wishes!

- Michael

BarracudaHockey

My Feedback: (11)

I wouldn't fly 3151's on anything bigger than a 30 size and even then I'd want something decent on the collective if I was doing hard 3d.

Michael211

My Feedback: (1)

Barracuda is there any reason not to use a S3151 on the throttle control however? I've never been especially clear on whether a basic/standard servo is Ok on the thottle of a heli or not. [8D]

Cheers!

- Michael

PlaneHeli

Michael211,

Thanks for the advice.

I have all Futaba S3001 servos on my Caliber 30, which are analog.

Im only hovering and slow forward flight at the moment, so maybe will make do for now and look at upgrading later.
I believe my Futaba CHP radio should have come with S3151 servos, but maybe the shop swapped them for the cheaper analog servos.

BarracudaHockey

My Feedback: (11)

No i use 3151's on throttle for quite a few of my machines. Faster throttle servos are nice on governors that use super servo mode where reaction time is more important. A properly rigged standard servo is all sport flyers will ever need. There are those that say throttle needs to be faster than collective but in general collective has more resistance and therefore can't move its rated speed anyway and a throttle has no resistance, also the throttle servo in idle up is moving nowhere near as far as the collective when doing things like tictocs where the pitch is going from one extreme to the other.

Michael211

My Feedback: (1)

Caliber,

<<Futaba CHP radio should have come with S3151 servos>>

Most of the 7C radios come with the S3151 digital servos but there is at least 1 config that I know of (7CAF) that comes standard with S3004 servos factory standard.

The 7CHF and 7CHP that I've seen listed on Tower Hobbies (and other places) include the S3151 digital servos. However there's no way to tell if this has always been the case... earlier (before I was even looking for a new radio) the 7C radios may not have included digital servos.

You'd need to go back to the original advertisement from which you purchased yours from and see what it specified to determine if you got ripped off or not.

Good luck.

- Michael

TomM

I'm wondering why a digital servo is less prone to failuer from vibration and stress. Is there a major difference in how they're made as in quality of bearings, gears, and/or soldering?. What would be better as far as reliability and quality... a $50 standard or a $50 digital? Would Hitec HS 625 MG or 925MG be ok in a 50 heli?

Tom

PlaneHeli

Michael211,

My Heli did come with S3001 as standard. I queried it at the shop I had bought it. He showed me the brochure. They come with S3001 servos , or S3004 servos.---and gyro. I bought it in Asia.

It appears there are many different combinations.

Will have to look at upgrading sometime. Shame I didnt know this until now, as I had just bought 4 S3001 servos for a new fixed recently.

Im just back into flying models after many years out of it. Gyros, computer Radios, its changed quite a lot over recent years. In the old days the only adjustments you could change was the servo horn length and position.
Ive just spent the last 2 days trying to sort out pitch curves, throttle curves, swash rates etc. LOL

PlaneHeli

What Digital servo would you recommend for a Caliber 30.

Im not into aeros yet but may later.

I have priced Futaba 9254 Digital servos at 150SGD each (93USD). Quite pricey for 4 of them.

What do you think is the best price/ per performance digital servo for a 30 class heli.

Do I require the Futaba S9254 servos.

Cheers

BarracudaHockey

My Feedback: (11)

9254 is a tail rotor servo, what you want, if you feel the need is 9252s though for a 30 the 3151 would be good enough on cyclic.

PlaneHeli

Thanks barra,

So what would you recommend Price / performance.

Tail = 9254
Collective = 9252
Cyclic = 3151
Throttle = 3001

Would I notice a difference now for hovering, forward flight (not into aeros yet). Or wait until im up to aeros level.

Some mentioned the analog (S3001) would be more prone to failure due stress in Helis. If true I would upgrade now.

BarracudaHockey

My Feedback: (11)

Sounds good to me, you could run a 3151 on throttle too, that way if you ever got a governor you'd already have a fairly zippy servo.

PlaneHeli

Thanks barra, will look into it and buy when I find a good price.