personally, i have never seen any data that would suggest that a lower priced servo or a smaller servo has a higher failure rate than anything else, and I have seen all kinds in applications. in over 20 years of tinkering with these things, and having used a whole bunch of different throttle servos in nitro helis, nitro airplanes, and gas airplanes i haven't seen anything that would lead me to conclude that any one thing is better than another.

What would be considered as a good throttle servo(7.4v) for a 30cc, something that is not going to break the bank.

Alan

Probably one of the newer HV hitec standard digital sevos with at lease carbonite gears. But i would prefer metal.

You couldnt pay me to put that servo in my plane....

Why? Any good scientific reason?

I just ordered a Hitec HS-5496MH metal gear servo for my new 37.5% Yak throttle.

The rest of the plane will have JR MP82T HV servos all around.

I've been using the Hitec 5665MH HV servo in several planes now.
Low cost, about $47 now (they dropped the price about $10), metal gears, fast enough for throttle and has plenty of torque. You can run them at 6v or HV. Work like a champ.

Align DS620 or the Savox equivalent,fast,accurate and reliable.

Originally Posted by Barn-E-Stormer

Why? Any good scientific reason?

I just ordered a Hitec HS-5496MH metal gear servo for my new 37.5% Yak throttle.

The rest of the plane will have JR MP82T HV servos all around.

With the horror stories people have been having, and first hand use... jitters...Hitec couldnt be farther off the radar for me. Former Hitec fan boy...no more

I have used the standard Futaba S3003 in all my gas airplanes with 6V.....pretty much what i have in the servo bucket i will use. It's fast enough for my style of flying. I haven't had any problems yet.....

I have had some old japan made JR 2721's for years that keep re-cycling into my throttles on my giants. They never stop.

I like using hxt900's form Hobby King! haha

I think it really depends on the carb you are putting the servo to. If you have a pretty stiff spring loaded carb, then you definitely need a quality high torque metal gear servo.

If your a person that likes to unhook the spring load on the carb, then you could get by with a more standard/cheaper servo (like a glow motor), although I would be hesitant to put a servo on throttle with nylon gears, ever.

I've been using JR 821HV's on my throttle's since they came out 3 years ago, with no issues.

One important thing to be aware of on throttle, is the end points vs trim in your radio setups. I work with a lot of people on their planes, and can tell you that more times than not, the throttle servo is setup wrong, and is binding at idle or full throttle because it is over driven.

Vibration is also a driving factor for throttle, more than torque.

Over the last 9 years I've been flying nothing but 35% and 40% planes. All I have ever used in any of them is a Futaba S3001 with nylon gears, 42 oz/in, 0.22 seconds, for throttle. I read somewhere years ago that they were pretty resistant to vibration so I started using them. I fly about 120 flights a year. I have had 320 flights on one 35%er, all with the same throttle servo. I recently had one start to jitter at the low throttle setting after 125 flights on a DA150.

I guess I figure the shake of the motor is side to side, not towards the servo, so it's not getting hammered by the pushrod.

It saves on battery life by not using a high powered servo. My throttle springs are always dismantled.

It's not a fast servo but I figure as long as it is .0001 faster than my engine is capable of spooling up the prop then why be any faster than that. But I do think I should be changing over to metal gears in the future.

Originally Posted by Bipe Me

Over the last 9 years I've been flying nothing but 35% and 40% planes. All I have ever used in any of them is a Futaba S3001 with nylon gears, 42 oz/in, 0.22 seconds, for throttle. I read somewhere years ago that they were pretty resistant to vibration so I started using them. I fly about 120 flights a year. I have had 320 flights on one 35%er, all with the same throttle servo. I recently had one start to jitter at the low throttle setting after 125 flights on a DA150.

I guess I figure the shake of the motor is side to side, not towards the servo, so it's not getting hammered by the pushrod.

It saves on battery life by not using a high powered servo. My throttle springs are always dismantled.

It's not a fast servo but I figure as long as it is .0001 faster than my engine is capable of spooling up the prop then why be any faster than that. But I do think I should be changing over to metal gears in the future.

That, what I highlighted in red above, is why you are able to use that servo for any length of time.

I also have used a futaba standard 3001 on throttle on a DLE 111 for a season. I actually even had HV going through it, or unregulated 7.4 2 cell Lipo, with no issues at all. I would guess somewhere around 100 flights before I lost the plane (unrelated to servo failure). But I also had disconected the spring load to the carb.

The standard servo's can and will work fine, but it all depends on the spring load on the carb. If you remove the spring load, there is no work load on the throttle servo at all, similar to a glow motor.

Spring load varies between carb's make and model's, so the servo needed will also vary.