Hello friends,
                  I need to buy servos,and came across basically three types i.e.Nylon gear, carbonite gear, metal gear.
I want to use them for my first Engined model whose flying weight will not exceed 1.25 kg.

Im confused whether carbonite or metal gear? I think they are long lasting than nylon ones..

My Suggestion is to go for metal gear servos.

depends also on your budget
how many needed and which brand

buy simple nylon geared ones - they are well up to the job.

its true that metal ones are better but you do not need
them for your model.

I fly .40 size models with standard nylon geared servos.

+1 to simple nylon servos, they are cheap.

nylon are cheap but they stip easily for stress but gears can be changed easily at not much cost.. metal are expensive but dont strip often but if they do then most of the time you just throw away the servo..

http://www.himodel.com/sort.php?brand=223

Though it's a few grams more, I'd go metal.

The failures goes in two moving parts.
1. Gear and
2. Pot inside for position feedback.

Let Analize financially.
Servo A
======
Lifetime = 100 flight, Cost = X,  .: Cost/Flight = X/100

Servo B
======
Lifetime = 10 flight, Cost = Y, .: Cost/Flight = Y/10

Now compaire between X/100 with Y/10 and take your decision.
Please note the costs are inclusive of postage and other costs.

This is only a economist's view only. Several factor have not been considered like changing servos, Failure of servo and loss/Damage of model due to servo failure etc.

However, I would second Saikatda. Use Nylon Servos. They are cost effective not only in short term but long term too taking replacement as required.

It would have to be a really cheap servo to last only 10 flights.

But I am totally with Saikat and Vinay. Nylon gears are more than good enough for your present requirement. Just don't compromise too much on price.

Hello All,
In my opinion the nylon gears are too good for this size of model as with this size (i am flying for more then 13 years) none of my nylon gear chipped unless it is a good crash.

For more safety you can go for Karbonite gears as they are said to be 4 times stronger than nylon ones.

The main thing that I recommend is to go with a branded servo like FUTABA, HITEC or JR. as with these I have never seen any unusual servo faliure or behavior, while experinced the same with some chinese brands.

nylon or karbonite gears for less slope. metal if u need something that will not strip

When you are starting new in the hobby get the normal nylon gear servos as they are cheap and you can replace them if required.

Metal geared are a must when there is a you use petrol engines as they are a must for the vibration and the high torque requriements for a larger plane.

Carbonite is a good trade off if you are flying expensive planes and are not big but expensive.