FallingWithStyle

Are ball bearing servos worth the extra cost and weight? Do they last longer or really run smoother or center better?

Thanks
Clark

Ed_Moorman

My Feedback: (1)

If you can't tell the difference, they aren't worth the money. Don't let someone browbeat you into something you don't need.

That being said, after flying them, I have a hard time not buying digital servos every time except for throttle. They are just that much more precise in centering, more powerful and have more holding power.

When you can fly well enough to notice that your ailerons do not center the same from a left bank and a right bank, it's time for some better servos. Ball bearings are not going to do much for you. They don't wear the plastic hole in the case like the non-bearing ones do. The non-bearing servos will get slop in the servo shaft. Coreless motor servos are OK, but the cat's meow, so to speak are the digitals. Expensive, but do I feel a difference.

dirtybird

My Feedback: (5)

Digital servos are better but I see a lot of fellows putting in negative expo after they install digitals. That does not make much sense.
Also digital servos are a power hog. With the engine running they can draw as much 250 ma without producing any torque. With four in the airplane thats 1A of power with the airplane sitting still and the engine running. A 600 ma battery will last only about 20 minutes so you need to go to at least a 2ah pack.
I think a set of good quality coreless servos are a better choice unless you have to have that last ounce of precision

Scar

My Feedback: (3)

As you can see by the previous posts, opinions vary.

I've had both, and never had much of a problem. Of course, I was flying trainer types with the bushing servos. With ball bearing servos, I have experience in ordinary aerobatic planes up to 72", and warbirds up to 100". No problems.

What are you flying? How big a difference in cost are you seeing between busing and ball-bearing servos? Does that amount seem significant to you? Do you yank & bank, or fly combat, or just burn holes in the sky? Are you heading toward an effort in Pattern Aerobatics? If you would provide this information, you will get even more opinions on the value of servos.

Good luck,
Dave Olson

FallingWithStyle

This is for my first real pattern plane. The Stevens Aero Cap 232 Electric. 55" wingspan. I really want to learn precision aerbatics with this plane. For the best reliability I'm going to use a PCM receiver. I'm going with a very good power plant after reading 100's of posts on this plane. This will be my new baby.

So I need 4 servos, and its only a $6/servo difference between HS-81's and HS-85's. The cost isn't really an issue, but they do weigh .12 oz more and weight is critical on this plane. But I really just want to know if there is any real perceivable difference.

I'm wary of going to digital servos because they are amp hogs and I really want long flight times (15-20 min) which seems to be just barely in range as it is.

Clark

bigbri

My Feedback: (287)

When the servos are brand new you will not notice the difference between BB and non BB. and quite frankly there will not be a difference. But after a while bushed servos get real sloppy at the ouput area....then things tend to get sloppy and the BB servos will shine. Now don't be fooled by single BB servos they develop slop at the bottom end of the final gear very quickly also. So if you want servos that stay tight for a long while double BB is the way to go........
Good luck on your purchase
Brian
P.S. Hitec 425 double BB are a great servo for the money....15 dollars at servo city and additional 15 % off for volume sales (4 or more)

XJet

I'll put in a vote for the HS425BB too -- I've got heaps of them and never had any problems with them. At the price they charge for a 425 it's just not worth buying a non-BB servo. If you need more torque then also take a look at the HS475.

GRANT ED

I had JR 577 standard bushed servos in my RV-4 for a year. I changed to ball bearing servos (sorry can't remember the number). I can honestly say I did not notice any difference. I consider myself to be an above average pilot at my field so I am no newby.
The bushed servos had no slop after a year of hard flying. I have some planes with digitals and they make a difference but the lower end of servos is much of a muchness.

FallingWithStyle

I'm sorry. You lost me there.

Clark

FallingWithStyle

Thanks. That makes a lot of sense. I'll go check these out. As long as they are not too heavy I'll probably go that way.
Clark

Dsegal

> much of a muchness <

Sorry, but most of us Yanks who speak 'Mer'can English won't get that phrase. Don't take it personally!

Jimmbbo

My $.02 - I use BB servos on high load, high use circuits (flight controls) and bushed servos on low load, low use systems (landing gear, throttle)...

Cheers!

Jim

bigbri

My Feedback: (287)

Oh one more note here on Bushed vs BB servos. Many people state they cannot feel the difference (when flying) between a BB servo ans a slightly worn bushed servo....and very well may not, But as more and more slop developes it very well could lead to control surface flutter....and that often leads to the death of an airplane. The control surface is "anchored" by the servo. It is impossible to install a decent slop free control surface with sloppy servos
My 2 cents
B-

FallingWithStyle

I'm convinced. This plane is all about precision so I'll go for BB servos. I have to go with a single BB design though; a double BB adds 1 oz per servo and I cannot afford a 4 oz weight penalty.
Thanks
Clark