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Servo Question

Old 03-22-2009, 11:57 AM
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Default Servo Question

I have a 27% Extra with a G62, after the maden flight that went perfect didn't have to trim a thing yesterday the elevator servo locked up. Fortunately I was on the ground, I bought this plane at a swap meet a few weeks ago. The elevator servo was a Hitec HS 705 MG, Searching tower and several other web sites this mornig it appears that this servo is no longer made, I'm interested in the Hitec 805BB, it appears that it has more torque and overall is a better servo however it has nylon gears.

Should this be a concern? If so what servo would you recomend, I fly with a 6 volt pack.

Thanks for your help
Old 03-22-2009, 12:10 PM
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Default RE: Servo Question

Not sure what your budget is but a 27% Extra with a G62 should only use metal gear. 5645MG from Hitec. Or a 645MG from Hitec. The 1st is digital and the second is analog. You can often find the 5645MG's used for $40 a pop. Only use metal gear over 100 ounces for planes over 90 sized. For 50cc and larger planes use 150 oz and up depending on the surface size and number of servos per surface. On my newest 50cc Extreme Flight Yak I use 7955TG all around which are 333 oz at 6 volts. With 6 volts you'll get some extra torque from the servos I listed above.
Old 03-22-2009, 12:38 PM
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Default RE: Servo Question

Now you see that servos do fail. If that plane doesn't have dual servos for the tail you should see the wisdome of putting another one there. You can way more often than not fly a plane with one aileron servo and no rudder servo but it's impossible to fly with no elevator servo.
since I lost a very nice SebArt 30e Sukhoi when the single servo died, all my planes, including the SebArt replacement has dual servos.
I would put a minimum force of two Hitech645 mg servos there.
Old 03-22-2009, 12:49 PM
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Default RE: Servo Question

Wow I didn't even think that he probably had only one servo on the entire elevator. Definitely always one servo per elevator half on these sized planes.

PS: We all did this in the beginning. I crashed my 1st 25% CAP 232 on servos that were not metal gear. I learn the hard way but I never forget.
Old 03-22-2009, 05:45 PM
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Default RE: Servo Question

Your correct I only had one servo, I can definetly see the wisdom in two, I'm surprised no one at the feild mentioned this. So how do I set this up? tie both seros togetehr or actaully have one control the left and the other control the right?

I should add that with the one servo setup I had a pull pull setup for the elevator
Old 03-22-2009, 08:02 PM
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Default RE: Servo Question

There should be slots in the tail for a servo to each side. Then program your radio for dual elevator servos or get a servo reversing device like this:
http://www3.towerhobbies.com/cgi-bin...?&I=LXANF2&P=0
or this
http://www.smart-fly.com/Products/Eq.../equalizer.htm
With the g62 up front balancing two servos in the tail shouldn't be a problem.
Old 03-23-2009, 11:34 AM
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Default RE: Servo Question

Altavillan def has you on the right track. What radio transmitter and receiver do you have baja?
Old 03-23-2009, 12:38 PM
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Default RE: Servo Question

i have plastic gear on my cap gp joe, do you think it's bad ?

regards

stephae
Old 03-23-2009, 01:55 PM
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Default RE: Servo Question

I have the Futaba 10 C with the 14 channel receiver in that plane, I also have a 72 module and fly the glow planes with 7 and 8 channel recievers. I ordered two Hitec 5645 MG today,

This plane was a midwest kit, so I'll have to cut into the ply on the sides to mount the servos it appears there is plenty of room.

Here's a question do you use extensions and just plug them together or solder the wire together? I'll need to measure tongiht I'm guessing I'll need about a 20 inch extenstion to run the servo wires up to the receiver.

Also what guage wire would you recomend from the controll surface to the servo?

edited for spelling
Old 03-23-2009, 02:06 PM
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Default RE: Servo Question

ORIGINAL: baja_236

I have the Futaba 10 C with the 14 channel receiver in that plane, I also have a 72 module and fly the glow planes with 7 and 8 channel recievers. I ordered two Hitec 5645 MG today,

This plane was a midwest kit, so I'll have to cut into the ply on the sides to mount the servos it appears there is plenty of room.

Here's a question do you use extensions and just plug them together or solder the wire together? I'll need to measure tongiht I'm guessing I'll need about a 20 inch extenstion to run the servo wires up to the receiver.

Also what guage wire would you recomend from the controll surface to the servo?
edited for spelling
With all those channels you won't need a match box or servo synchronizer. Just use two channels on the rx and buy two extensions. I use Maxx products HD extensions which are 22 gauge. You can use the pre-canned ailavator mix (CH2 and CH8) or just do a custom pmix (CH2 master to CH5 slave). Both are soo easy to do.

I'm a little confused about the gauge of wire from control surface to the servo. Do you mean a pull pull cable? You are using push rods correct?
Old 03-23-2009, 02:16 PM
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Default RE: Servo Question

Try this servo out. Way better than a Hitec 645. No centering issues and a cheaper price. A buddy and me bought a few of these to try them out when they were $7 cheaper than they are now. Nice and smooth, center great, and are pretty fast on 6 volts. Pretty powerful also. He had one on the rudder of his 13 pound Extra and knife loops were no problem. I made the switch to digitals awhile back and thought that I'd never run nothing but 8611A's in my 50cc planes. This servo changed that.

[link]http://hobbypeople.net/gallery/474142.asp[/link]
Old 03-23-2009, 02:47 PM
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Default RE: Servo Question

Baja, I have this plane and it should have the servo mounts already cut out. They are right under the front of the stab. I believe they were pre cut from the factory and the previous owner probably just covered over them. Once you get it set up it's a great flying plane, you'll enjoy it.
Old 03-23-2009, 02:53 PM
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Default RE: Servo Question

I'll be switching to a push rod setup when I move the servos
Old 03-23-2009, 03:30 PM
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Default RE: Servo Question

Idea for pushrods: 4-40 threaded rod with CF sleeve around it. Use 4-40 nuts on end of CF sleeve secured with your favorite thread locker or CA. Ball 4-40 ball ends on the ends of the push rods.
Old 03-23-2009, 04:34 PM
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Default RE: Servo Question

To save weight I solder up extensions. For long tail runs I make one servo lead long enough to reach the reciever. On that lead I solder in a wye for the +- power to the other servo near the tail close to the servo. On the reciever end of this extension I add another connection to get more amps sent down the wire. Then shorten the lead to the second servo and plug it in there at the first servo, and run the signal wire to the reciever. I get by fine using 22ga wire this way. 22ga wire will fow about 15 amps for 4' no problem. The connectors however are only good for about 4 amps and are the weak link. Saves an ounce or two and is fun so why not.
Old 03-23-2009, 06:37 PM
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Default RE: Servo Question

I'm with you-get rid of them connectors. Joe- are you using ball links on both ends? I've done it that way for years but have recently been told that I should use a non moving clip on one end. I've never had a problem though.
Old 03-23-2009, 07:59 PM
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Default RE: Servo Question

mrb,

Yes I use one on each end but I'm sure putting a fixed one on one end wouldn't hurt as long as the rod can twist as far as it needs to during full swing. Having a moving joint on each end doesn't hurt either.
Old 03-24-2009, 08:03 AM
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Default RE: Servo Question

Thanks, Joe. I'm not going to fix what isn't broken.

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