Throttle servo recommendations for 50cc
03-28-2009, 09:46 PM
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Throttle servo recommendations for 50cc
Hi everyone
Currently putting together a 50CC extra, and have hitec 7955's all around. What is the recommended servo for the throttle? I am using a DA50 engine. Should I also go with a 7955 there as well? If not, do I need to stick with a metal geared servo? Thanks for your help
Andy
Currently putting together a 50CC extra, and have hitec 7955's all around. What is the recommended servo for the throttle? I am using a DA50 engine. Should I also go with a 7955 there as well? If not, do I need to stick with a metal geared servo? Thanks for your help
Andy
03-28-2009, 10:12 PM
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RE: Throttle servo recommendations for 50cc
I am by no means an expert on this since I have just completed my first gasser but I think you would be fine with any standard digital servo. I used a Futaba 3152 for my throttle. I don't see where a metal geared servo would be needed for the throttle but digital would be preferred for a consistant idle.
03-28-2009, 10:26 PM
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RE: Throttle servo recommendations for 50cc
I have read many times that the shock and vibration from a gasser can easily shatter the nylon gears.I 'd go with a metal one.
03-28-2009, 10:30 PM
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RE: Throttle servo recommendations for 50cc
Just use a standard metal gear servo and you'll be fine. You won't gain an advantage using a digital servo on the throttle. I'm using Hitec 425s and no problems. Speed of the servo is greater than the engine's ability to react to the throttle movement.
03-28-2009, 11:00 PM
#6
RE: Throttle servo recommendations for 50cc
My early experiences with non metal geared throttle servos for gassers has me using nothing but metal geared servos. Ruined several great flying days with stripped nylon geared throttle servos[
]
]
03-28-2009, 11:03 PM
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RE: Throttle servo recommendations for 50cc
I like the Hobbyco cs35. It's a rebadged Hitech 225 mg mini servo. http://www3.towerhobbies.com/cgi-bin...?&I=LXLN95&P=0
Good speed, very well made and slop free gears and a good price.
Good speed, very well made and slop free gears and a good price.
03-28-2009, 11:11 PM
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RE: Throttle servo recommendations for 50cc
The plastic gear servos should work for a while. If thats what you have, use them. Heck we all use plastic horns on the throttle. Evan more important than MG servos is eliminating vibration. A strong solid engine mount is a great place to start.
03-28-2009, 11:14 PM
#10
RE: Throttle servo recommendations for 50cc
Actually I got away with it for awhile. Took a little time for the vibration to take it's toll. Just wouldn't be that pleasant if she decides to let go in a low torque roll![X(] I was lucky, One gave up on base leg with ample altitude and the other on the ground during run- up.
03-29-2009, 04:09 AM
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RE: Throttle servo recommendations for 50cc
Get another 7955. You want an accurate servo with good resolution. Seen/heard of two deadsticks more than likely due to inaccurate standard servos, one involved the loss of 35%er.
03-29-2009, 10:41 AM
#12
RE: Throttle servo recommendations for 50cc
Well one other thought about throttle servos on gassers;
Since gassers are so sensitive coming right off idle, you have to pay attention to the geometry of the linkage setup and if you use a programmable Hitec it makes the setup also easier to compensate for limitations on what you can do with the actual hardware. While there are a few tricks you can use on radio setup depending on your tx, those should not be thought of as compensating for a poor mechanical/geometry setup of the servos/linkages anywhere on the model
If you've got an extra 7955 kicking around, you could easily use that but I've gone to a smaller Hitec digital with metal gears so I can also program them, works great.
Since gassers are so sensitive coming right off idle, you have to pay attention to the geometry of the linkage setup and if you use a programmable Hitec it makes the setup also easier to compensate for limitations on what you can do with the actual hardware. While there are a few tricks you can use on radio setup depending on your tx, those should not be thought of as compensating for a poor mechanical/geometry setup of the servos/linkages anywhere on the model
If you've got an extra 7955 kicking around, you could easily use that but I've gone to a smaller Hitec digital with metal gears so I can also program them, works great.
03-30-2009, 08:42 AM
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RE: Throttle servo recommendations for 50cc
ORIGINAL: Eagleburger
You want an accurate servo with good resolution. Seen/heard of two deadsticks more than likely due to inaccurate standard servos, one involved the loss of 35%er.
You want an accurate servo with good resolution. Seen/heard of two deadsticks more than likely due to inaccurate standard servos, one involved the loss of 35%er.
03-30-2009, 10:46 AM
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RE: Throttle servo recommendations for 50cc
ORIGINAL: RC_Fanatic
Curious! The throttle ratchet on most transmitters has a resolution of about 20. Any servo I've seen is a lot better than that.
ORIGINAL: Eagleburger
You want an accurate servo with good resolution. Seen/heard of two deadsticks more than likely due to inaccurate standard servos, one involved the loss of 35%er.
You want an accurate servo with good resolution. Seen/heard of two deadsticks more than likely due to inaccurate standard servos, one involved the loss of 35%er.
One of the Reasons I use a Heli TX.
03-30-2009, 11:54 AM
#16
RE: Throttle servo recommendations for 50cc
ORIGINAL: Eagleburger
Get another 7955. You want an accurate servo with good resolution. Seen/heard of two deadsticks more than likely due to inaccurate standard servos, one involved the loss of 35%er.
Get another 7955. You want an accurate servo with good resolution. Seen/heard of two deadsticks more than likely due to inaccurate standard servos, one involved the loss of 35%er.
03-30-2009, 12:17 PM
#17
RE: Throttle servo recommendations for 50cc
I prefer a servo that is extremely accurate in centering. Having a servo that will repeat the idle position every time is more important to me than a fast servo. Most servos will actually travel faster than a gas engine can respond anyway. Accuracy is WAY more important than speed IMO.
I use nylon geared servos all the time. Never had any problems. But I also use sullivan graphite pushrods and mount my servos at least 12" away from the engine compartment. I still follow the old rules of installation when it comes to the ignition box. (12" rule) By using the longer pushrod I believe it gives some vibration isolation.
Consider which will provide more isolation from the vibration....... a servo mounted 5" from the engine and a metal pushrod with ball links on both ends..... or...... a servo mounted at the back of the wing saddle and a 30" long pushrod with ball links on both ends....
Thats just what I do. I'm sure anybody could point out some flaws in my setup. It's probably not the "best" way to do it, but it does work.
I use nylon geared servos all the time. Never had any problems. But I also use sullivan graphite pushrods and mount my servos at least 12" away from the engine compartment. I still follow the old rules of installation when it comes to the ignition box. (12" rule) By using the longer pushrod I believe it gives some vibration isolation.
Consider which will provide more isolation from the vibration....... a servo mounted 5" from the engine and a metal pushrod with ball links on both ends..... or...... a servo mounted at the back of the wing saddle and a 30" long pushrod with ball links on both ends....
Thats just what I do. I'm sure anybody could point out some flaws in my setup. It's probably not the "best" way to do it, but it does work.
03-30-2009, 12:32 PM
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RE: Throttle servo recommendations for 50cc
ORIGINAL: Zeeb
it makes the setup also easier to compensate for limitations on what you can do with the actual hardware.
it makes the setup also easier to compensate for limitations on what you can do with the actual hardware.
Like what??
03-30-2009, 12:46 PM
#19
RE: Throttle servo recommendations for 50cc
ORIGINAL: exeter_acres
Like what??
ORIGINAL: Zeeb
it makes the setup also easier to compensate for limitations on what you can do with the actual hardware.
it makes the setup also easier to compensate for limitations on what you can do with the actual hardware.
Like what??
I suppose one might accomplish something with a throttle curve in the tx, but that doesn't allow you to use the higher ATV settings and better resolution.
JMHO, YMMV....
03-30-2009, 12:55 PM
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RE: Throttle servo recommendations for 50cc
ORIGINAL: Zeeb
I suppose one might accomplish something with a throttle curve in the tx, but that doesn't allow you to use the higher ATV settings and better resolution.
JMHO, YMMV....
ORIGINAL: exeter_acres
Like what??
ORIGINAL: Zeeb
it makes the setup also easier to compensate for limitations on what you can do with the actual hardware.
it makes the setup also easier to compensate for limitations on what you can do with the actual hardware.
Like what??
I suppose one might accomplish something with a throttle curve in the tx, but that doesn't allow you to use the higher ATV settings and better resolution.
JMHO, YMMV....
Why not?
03-30-2009, 05:07 PM
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RE: Throttle servo recommendations for 50cc
ORIGINAL: Rcpilot
I prefer a servo that is extremely accurate in centering. Having a servo that will repeat the idle position every time is more important to me than a fast servo. Most servos will actually travel faster than a gas engine can respond anyway. Accuracy is WAY more important than speed IMO.
I use nylon geared servos all the time. Never had any problems. But I also use sullivan graphite pushrods and mount my servos at least 12" away from the engine compartment. I still follow the old rules of installation when it comes to the ignition box. (12" rule) By using the longer pushrod I believe it gives some vibration isolation.
Consider which will provide more isolation from the vibration....... a servo mounted 5" from the engine and a metal pushrod with ball links on both ends..... or...... a servo mounted at the back of the wing saddle and a 30" long pushrod with ball links on both ends....
Thats just what I do. I'm sure anybody could point out some flaws in my setup. It's probably not the "best" way to do it, but it does work.
I prefer a servo that is extremely accurate in centering. Having a servo that will repeat the idle position every time is more important to me than a fast servo. Most servos will actually travel faster than a gas engine can respond anyway. Accuracy is WAY more important than speed IMO.
I use nylon geared servos all the time. Never had any problems. But I also use sullivan graphite pushrods and mount my servos at least 12" away from the engine compartment. I still follow the old rules of installation when it comes to the ignition box. (12" rule) By using the longer pushrod I believe it gives some vibration isolation.
Consider which will provide more isolation from the vibration....... a servo mounted 5" from the engine and a metal pushrod with ball links on both ends..... or...... a servo mounted at the back of the wing saddle and a 30" long pushrod with ball links on both ends....
Thats just what I do. I'm sure anybody could point out some flaws in my setup. It's probably not the "best" way to do it, but it does work.
Good advice, especially the bold typefaced.
I use digitals with plastic gears, nyrods, servo mounted on or near gear plate and never had a problem. Usually with mini servos to boot. just started to use 7955 on my two latest and they are the best of both worlds.
03-31-2009, 11:33 AM
#22
RE: Throttle servo recommendations for 50cc
ORIGINAL: exeter_acres
Why not?
ORIGINAL: Zeeb
I suppose one might accomplish something with a throttle curve in the tx, but that doesn't allow you to use the higher ATV settings and better resolution.
JMHO, YMMV....
ORIGINAL: exeter_acres
Like what??
ORIGINAL: Zeeb
it makes the setup also easier to compensate for limitations on what you can do with the actual hardware.
it makes the setup also easier to compensate for limitations on what you can do with the actual hardware.
Like what??
I suppose one might accomplish something with a throttle curve in the tx, but that doesn't allow you to use the higher ATV settings and better resolution.
JMHO, YMMV....
Why not?
