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Need advise on steering servo/s for 7.5cc outboard?

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Need advise on steering servo/s for 7.5cc outboard?

Old 07-27-2007, 09:26 PM
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MyStar
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Default Need advise on steering servo/s for 7.5cc outboard?

Hi all,

This is my first tunnel hull and I would appreciate your input.

I'm in the process of finishing a Prather "32" Racing Tunnel" with a stock K&B 7.5cc outboard and would like to hear what you all are using for your steering servo/s?. Should I run one or two; quarter scale or standard size; metal or plastic gears?


Thanks,

Don
Old 07-27-2007, 09:27 PM
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iowapiper_rcp
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Default RE: Need advise on steering servo/s for 7.5cc outboard?

1/4 scale, metal gear, HIGH TQ
Old 07-27-2007, 10:26 PM
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Ron Olson
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Default RE: Need advise on steering servo/s for 7.5cc outboard?

Something with at least 100 oz. in. of torque. You can find that much now in a standard sized servo.
Old 07-28-2007, 08:40 AM
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RaysonCraft
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Default RE: Need advise on steering servo/s for 7.5cc outboard?

My buddy runs two MG High Torque standard size. That way there is less stress on the output shaft and bearings. I've heard that at least 150oz is better. I"ve always thought that metal gears are a good way to go in case the engine hits something.
Old 07-28-2007, 03:35 PM
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Hesco Racing
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Default RE: Need advise on steering servo/s for 7.5cc outboard?

Just remember somethings got to give when you hit something. A servo can be replaced farely quickly. A broken leg well thats a different story.
Old 07-30-2007, 04:59 AM
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Jan_the_man
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Default RE: Need advise on steering servo/s for 7.5cc outboard?

Does it matter if you run an analog or digital servo on the boats? which is the prefered way to go?

In the two tunnel that we run we have the Hitec 755HB and E-Servo 615 respectively. Both 1/4 scale size analog on 6Volt. But you can get close to that torque out of a Futaba 9255 digital servo on 4.8Volt with about 125oz/in.
Old 07-30-2007, 07:06 AM
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Dan S
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Default RE: Need advise on steering servo/s for 7.5cc outboard?

either or is your choice.

Digital are a bit more money than the analog servos, ensure the radio you use can be used with digital servos.

I also believe that you can't mix analog and digital together, well I know with my radio system I can use either or but not both mixed.

Dan.
Old 08-07-2007, 10:22 AM
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MyStar
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Default RE: Need advise on steering servo/s for 7.5cc outboard?

Thanks for all your advise guys!

I ended up buying one 1/4 scale Hitec HS-755MG. I've seen this particular servo installed by boat manufactures on 45" plus gas hulls.

Here's the specs:
Metal geared
Dual ball bearing output spline
Water and dust tight
Speed: .28 sec/60° @ 4.8V, .23 sec/60° @ 6V
Torque: 166.64 oz in @ 4.8V, 199.97 oz in @ 6V

I think for the money ($39.99) I made a good choice.


Don
Old 08-07-2007, 03:51 PM
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ryan_t888
 
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Default RE: Need advise on steering servo/s for 7.5cc outboard?

That should be more than enough. I have one of those twisting a rudder on my gasser.

My radio box is only big enough to fit a standard size servo with a small servo horn on my 7.5 tunnel. I'm running the Hitec HS-5645 digital servo. I prefer Futaba as Hitec typically gives me some trouble now and then.

My Futaba throttle servo is analog and my Hitec Steering servo is digital. So far it's compatible. The radio is a Futaba 3PM.

Ryan
Old 08-07-2007, 08:56 PM
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Dan S
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Default RE: Need advise on steering servo/s for 7.5cc outboard?

I stand corrected,

I just check my book and I can mix digital and analog servos.

Dan.

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