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Servo question.

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Old 06-17-2004, 10:26 AM
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Sport_Pilot
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Default Servo question.

I bought an Excite 90 and the instructions recommend that the servos have at least 65 oz. in. of torque. I was wondering that since digital servos have more pull near the center, if I could get away with digital servos with 61 oz. in. of torque?

Also is the advantage of digital servos something measurable? I don't see any differance on the Servo City specs.
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Old 06-17-2004, 11:15 AM
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Default RE: Servo question.

If the specs recommend 65 I would not go with something with 61. It is always ok to put something with more power than recommended, but NEVER ok to put something with less power, no sense in saving some money by skimping on servos then destroying the whole plane because the servo could not move the control surface under load.

just my .02
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Old 06-17-2004, 11:40 AM
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Default RE: Servo question.

then destroying the whole plane because the servo could not move the control surface under load.
I don't think that is the case, there are two servos for the wing, but the control servos are very large. I think the large torque is to help prevent flutter. It is a 90 sized plane and non 3D planes do not require this much torque.
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Old 06-17-2004, 11:44 AM
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Default RE: Servo question.

Personally, you could fly that plane with standard servos and still be okay. Depending how you fly and your system to feed the batteries juice.

Any standard digital servo would work great for that plane. IMO, don't go and spend $100 on a JR 8611 and put it in a plane worth 200$. Whats the point?

Digitals are just an accessory with the small planes and profiles. People using them like them because they do make your plane fly that much smoother. However, it is not at all necessary.

Now if your plane was a gasser or a 35-40% then yes, thats where IMO Digital Coreless servos are an absolute necessity.

Now I have not seen the Excite 90, but sounds like a 3D plane, what exact sport digital were you looking at? Has to be a Hitec right? If so, those would work just dandy. Just make sure you get a quality battery, if you can, Li Ion or something capable of handling a good amp load and 6v.
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Old 06-17-2004, 11:46 AM
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Default RE: Servo question.

I don't think that is the case, there are two servos for the wing, but the control servos are very large. I think the large torque is to help prevent flutter. It is a 90 sized plane and non 3D planes do not require this much torque.
This may be true, I wont argue that. But, even flutter can strip gears and cause the total loss of the airplane. Like I said before it is only my opinion, but I for one will not put things that are less then whats recommended. It is not worth it to me. Money or safety wise.

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Old 06-17-2004, 01:14 PM
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Default RE: Servo question.

Steve,
I was looking at the Hitec 5745HB and was planning to use an existing nicad pack. I was planning to use a standard flight pack and thought if I have to upgrade the servo's then I might as well spend a little extra for digital servos, guess I might as well spend more for batterys it will certainly have over 65 oz. in. with the extra 1.2V. Don't agree with using Li-Po though, rather use nickle hydride now they have been on the market awhile, though am a little concerned about rapid charging. If not then 6V nicad pack.
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Old 06-17-2004, 03:28 PM
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Default RE: Servo question.

I am sorry, I went and looked up the specs for the HS-5475HB, and the 61 is at 4.8v so if you run it at 6v it will be fine, I had misunderstood and was thinking that 61 was the max output of that servo.

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Old 06-17-2004, 05:09 PM
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Default RE: Servo question.

Thats a fine servo for the plane. With digital, it is even better.
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