Which servo on throttle
08-24-2011, 09:22 AM
#26
My Feedback: (19)
RE: Which servo on throttle
Many of the optical kill switches have a good record for reliability ... others not so good! I'll let you do the research on the various forums to determine which one might best suit your needs. Don't want to start a war here because I said something bad (or truthful) about someones favorite product so I won't say anything about any of them!
08-24-2011, 01:11 PM
#28
RE: Which servo on throttle
7965MG. It's the most accurate/repeatable/centering Hitec servo with great speed from a few that have tested many. Many of us run this as throttle servos on our GS gassers. I too cheaped out on my first set of throttle servos and have since learned my lesson. The ability to always have the engine return to the perfect idle setting is priceless. On my smaller 30%, the throttle servo is the most expensive servo in the plane! No more messing around with throttle trim on every single stall spin or landing...
Make sure you use a CF rod + plastic arm on the servo, or if not CF, then plastic dubro rod. I've switched to CF as I found temp changed the length of the plastic rod too much. You need to be sure to dampen that vibration, especially if installing the servo in the motor box. Of course this isn't really a big issue on a smooth twin or even the DLE-20 vs on the DLE-55 single for example.
As good as plastic gears sound in theory, its best to dampen the vibration before it even arrives at the servo spine via plastic. Plastic geared sevos in shaky gassers have failed many times over so it's not really worth the risk.
Analog vs digital I wont get into, but analog technically wont max deflect on failure. I wouldn't be too concerned about this though. THat's why we run opti-kills.
Make sure you use a CF rod + plastic arm on the servo, or if not CF, then plastic dubro rod. I've switched to CF as I found temp changed the length of the plastic rod too much. You need to be sure to dampen that vibration, especially if installing the servo in the motor box. Of course this isn't really a big issue on a smooth twin or even the DLE-20 vs on the DLE-55 single for example.
As good as plastic gears sound in theory, its best to dampen the vibration before it even arrives at the servo spine via plastic. Plastic geared sevos in shaky gassers have failed many times over so it's not really worth the risk.
Analog vs digital I wont get into, but analog technically wont max deflect on failure. I wouldn't be too concerned about this though. THat's why we run opti-kills.
08-24-2011, 01:47 PM
#30
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RE: Which servo on throttle
If you guys flying the GS gassers are having that much vibration, I'd be looking at finding what's causing it. As far as using CF for a throttle pushrod, I guess that's okay but I've always leaned towards using non-metallic materials. CF is just as conductive as a metal push-rod. The end piece is the key though, a CF rod with nylon connectors would probably be very acceptable. The main thing would be to ensure the CF rod did not come in contact with other metal structures in the airframe. As to an earlier post in this thread, not using bell-cranks would not limit the use of Zenoah engines. Z makes what they call a straight shot manifold that would negate the use of the bell crank system.
Happy Flying!
Loopman
Happy Flying!
Loopman
08-24-2011, 01:48 PM
#31
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RE: Which servo on throttle
ORIGINAL: Eganwp
7965MG. It's the most accurate/repeatable/centering Hitec servo with great speed from a few that have tested many. Many of us run this as throttle servos on our GS gassers. I too cheaped out on my first set of throttle servos and have since learned my lesson. The ability to always have the engine return to the perfect idle setting is priceless. On my smaller 30%, the throttle servo is the most expensive servo in the plane! No more messing around with throttle trim on every single stall spin or landing...
Make sure you use a CF rod + plastic arm on the servo, or if not CF, then plastic dubro rod. I've switched to CF as I found temp changed the length of the plastic rod too much. You need to be sure to dampen that vibration, especially if installing the servo in the motor box. Of course this isn't really a big issue on a smooth twin or even the DLE-20 vs on the DLE-55 single for example.
As good as plastic gears sound in theory, its best to dampen the vibration before it even arrives at the servo spine via plastic. Plastic geared sevos in shaky gassers have failed many times over so it's not really worth the risk.
Analog vs digital I wont get into, but analog technically wont max deflect on failure. I wouldn't be too concerned about this though. THat's why we run opti-kills.
7965MG. It's the most accurate/repeatable/centering Hitec servo with great speed from a few that have tested many. Many of us run this as throttle servos on our GS gassers. I too cheaped out on my first set of throttle servos and have since learned my lesson. The ability to always have the engine return to the perfect idle setting is priceless. On my smaller 30%, the throttle servo is the most expensive servo in the plane! No more messing around with throttle trim on every single stall spin or landing...
Make sure you use a CF rod + plastic arm on the servo, or if not CF, then plastic dubro rod. I've switched to CF as I found temp changed the length of the plastic rod too much. You need to be sure to dampen that vibration, especially if installing the servo in the motor box. Of course this isn't really a big issue on a smooth twin or even the DLE-20 vs on the DLE-55 single for example.
As good as plastic gears sound in theory, its best to dampen the vibration before it even arrives at the servo spine via plastic. Plastic geared sevos in shaky gassers have failed many times over so it's not really worth the risk.
Analog vs digital I wont get into, but analog technically wont max deflect on failure. I wouldn't be too concerned about this though. THat's why we run opti-kills.
08-24-2011, 01:51 PM
#32
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RE: Which servo on throttle
Ernie
The function of the optical connection allows the receiver to be positioned well away from the ignition switch with no electrical connection that could introduce interference
into the receiver.
Whilst optical switches are very reliable, like any electronic unti they are not immune to malfunction. The optical receiver shuts off the ignition when it fails to see the light signal from the fibre. It does not know whether this was caused by a signal from the receiver or the transmitter failing!
BTW, yes I do use them on all my gas engines.
Terry
The function of the optical connection allows the receiver to be positioned well away from the ignition switch with no electrical connection that could introduce interference
into the receiver.
Whilst optical switches are very reliable, like any electronic unti they are not immune to malfunction. The optical receiver shuts off the ignition when it fails to see the light signal from the fibre. It does not know whether this was caused by a signal from the receiver or the transmitter failing!
BTW, yes I do use them on all my gas engines.
Terry
08-24-2011, 02:30 PM
#33
My Feedback: (19)
RE: Which servo on throttle
ORIGINAL: Redback
Ernie
The function of the optical connection allows the receiver to be positioned well away from the ignition switch with no electrical connection that could introduce interference
into the receiver.
Whilst optical switches are very reliable, like any electronic unti they are not immune to malfunction. The optical receiver shuts off the ignition when it fails to see the light signal from the fibre. It does not know whether this was caused by a signal from the receiver or the transmitter failing!
BTW, yes I do use them on all my gas engines.
Terry
Ernie
The function of the optical connection allows the receiver to be positioned well away from the ignition switch with no electrical connection that could introduce interference
into the receiver.
Whilst optical switches are very reliable, like any electronic unti they are not immune to malfunction. The optical receiver shuts off the ignition when it fails to see the light signal from the fibre. It does not know whether this was caused by a signal from the receiver or the transmitter failing!
BTW, yes I do use them on all my gas engines.
Terry
08-24-2011, 03:02 PM
#34
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RE: Which servo on throttle
ORIGINAL: Loopman
If you guys flying the GS gassers are having that much vibration, I'd be looking at finding what's causing it. As far as using CF for a throttle pushrod, I guess that's okay but I've always leaned towards using non-metallic materials. CF is just as conductive as a metal push-rod. The end piece is the key though, a CF rod with nylon connectors would probably be very acceptable. The main thing would be to ensure the CF rod did not come in contact with other metal structures in the airframe. As to an earlier post in this thread, not using bell-cranks would not limit the use of Zenoah engines. Z makes what they call a straight shot manifold that would negate the use of the bell crank system.
Happy Flying!
Loopman
If you guys flying the GS gassers are having that much vibration, I'd be looking at finding what's causing it. As far as using CF for a throttle pushrod, I guess that's okay but I've always leaned towards using non-metallic materials. CF is just as conductive as a metal push-rod. The end piece is the key though, a CF rod with nylon connectors would probably be very acceptable. The main thing would be to ensure the CF rod did not come in contact with other metal structures in the airframe. As to an earlier post in this thread, not using bell-cranks would not limit the use of Zenoah engines. Z makes what they call a straight shot manifold that would negate the use of the bell crank system.
Happy Flying!
Loopman
Those of us GS guys, and I'm most certainly one of those, that have been doing it for awhile have no problems at all with vibration. We don't often, if ever, experience servo failures, the linkage always remains attached to both ends of the installation, and throttle response is crisp, accurate, and provides great idle repeatability. In short, we do it right the first time and don't have the worries and problems that are so frequently discussed in this forum. We also do not try to penny pinch an installation, generating a set of problems germain to cheap and sub standard equipment. We've found that using the good stuff the first time permits us to fly problem free while the others are in the pits trying to fix their planes. We get a lot more trouble free flying time that way.
The above was not a slam against anyone, but a truthful statement that many could benefit from if they chose to do so. As for carbon fiber being a problem, it's not really if one isolates properly. I've flown a great many planes made entirely from carbon fiber through thunderstorms. The C/F did not generate any issues, and I know of only one plane lost to a direct lightning strike. People need to step up to at least the 20th century, and preferably the 21st.
08-24-2011, 03:11 PM
#35
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RE: Which servo on throttle
Correct, the servo signal is fed into an opto coupler in the ignition kill switch, this breaks the path for any stray RF noise from the kill switch from being coupled to the servo signal lead to the receiver. The opto coupler is just an electrical signal input turned into an optical signal, then back to an electrical signal output, all within the device.
Pete
Pete
08-24-2011, 05:41 PM
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RE: Which servo on throttle
I think I would conclude this with a Futaba 3305 or Hitec 645MG or something like that- std BB MG servo that is decently cheap but not low quality
Ameyam
Ameyam
08-24-2011, 06:14 PM
#37
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RE: Which servo on throttle
I like to use on the throttle HS-5245MG “digital mini”. At 1.12 oz is lighter then full size servo. If I’m using a servo to operate the choke, HS-225mg is my choice.
