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Aileron servos???

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Old 03-11-2002, 06:03 PM
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DeadMeat
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Default Aileron servos???

I have just started on my second RC plane. The TF Contender. This model calls for wing-mounted aileron servos. Now I am at a loss as to what kind of servos to stick there. I suppose the standard servos would be OK, but I would like to put something smaller/lighter on the wing. I am looking at Futaba S9602 or Hitec HS-225MG servos to go with my T6XAS/R127DF setup. What servos would you folks recommend for this airplane.
Any advice would be greatly appreciated.

Tom
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Old 03-11-2002, 06:27 PM
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flatfour
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Default Aileron servos???

For this type of plane, coreless and metal gear servos is overkill. Have a look at Hitec HS-85. They are just as strong as a "standard" servo. The Futaba "equivalent" according to thier web page is the S3102.

http://www.futaba-rc.com/servos/servo-compare.html

In my book, price wins for this one.

Are you doing the optional flaps?
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Old 03-11-2002, 06:30 PM
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Default Contender wing servos

Even if you end up on the heavy side (6.5-7 lbs) and go for a .60 size powerplant, the Hitec HS-85BB at 42 oz.in. will give you standard size torque, and save you a full ounce on each wing, two ounces total savings. You will not need the 55 oz.in. torque of the HS-225, and I don't know why you would want the extra weight (and expense) of metal gears on ailerons. At $23 each(ServoCity), you will be spending about $20 extra to save 2 oz. of weight. I'm not sure this is money well spent on your second plane, but if you were thinking of competitive flying, it would be justified. Maybe it's worth it just for the experience. Plus you can always use the servos in later planes.
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Old 03-11-2002, 06:47 PM
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Default Thanks for the info...

I was looking at the Hitec HS-85. The only thing I was concerned with was the 2 on the HS-85 vs 4 on the HS-225 screw mount. Should I be concerned about that? As you can tell I am pretty new at this and have no idea what kind of torque is needed for the ailerons.

Tom

P.S. Yes I will build the optional flap on my Contender.
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Old 03-11-2002, 09:31 PM
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Default two screw mount

If you are putting one servo on each flap and each aileron, now you're looking at a 4 oz. weight saving, which begins to be very considerable. Mount the servo so the long dimension runs front to back, use the Hitec hardware and 1/4" birch ply to mount the servo to and you will have no problem.

Most sport planes, even .60 powered, fly just fine with one standard servo driving two ailerons, 44 oz.in. torque divided between two control surfaces. The HS85BB will give you nearly double that torque on each surface, so torque will not be a problem.
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Old 03-11-2002, 09:44 PM
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Default servo torque calculator

Click on http://www.multiplexrc.com/calcservo.htm for an on-line servo torque calculator.
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Old 03-12-2002, 02:31 PM
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Default Thanks for the info.

I will go with the HS-85 servos. I'll just have to box them with some balsa stock. The way the servos mount up in the Contender wing right now is between two 1/4"x1/4" pieces of basswood stock. There is no support on the sides. With only one screw holding the servo at each end, I fear the servos would twist side to side. I think two pieces of 1/4"x1/4" balsa stock will solve that problem.

Tom
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Old 03-12-2002, 05:39 PM
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Default Aileron servos

How much torque does he need for the ailerons on that plane ?
May be he can even get away with the HS-81's ?

Michael
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Old 03-12-2002, 08:19 PM
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Default HS-81 aileron servos

MTT, you're probably right. I considered the HS-81, but something led me on to the HS-85. I think the 81 uses plastic bushings, whereas the 85 has BB top, which I thought would be more appropriate for getting back to neutral. I regard the 81 as a great throttle servo. But torque-wise, the 81's 32 oz-in per surface on a Contender wing should be no problem.
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