Servo Torque - Please help!
10-28-2008 | 10:10 AM
#1
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From: Clarksville,
MD
Servo Torque - Please help!
Guys -
I am moving to my first big 3d plane. I have been flying a funtana 90 for about a year now and I really want to move big. I am lookinig at the Dietrich 75cc Extra 260 ARF (http://www.dietrichaircraft.com/75cc...ccExtra260.php)
It calls for servors with 180-330 ounce minimum of Torque. This is where I need help. Are there specific servos you all have had luck with that are over 330 ounces of torque???? Or would you recomend one of those pull pull devices that lines the servos up in a row and links them together? And if you link the servos together, what is the formula to determine the overall torque of the multiple servos in a row (do you just add the torque ratings together - meaning 2 150 ounce servos in a a row is 300? ounces?)???
Respectfully I am hoping to get some good facts on this.
thanks
I am moving to my first big 3d plane. I have been flying a funtana 90 for about a year now and I really want to move big. I am lookinig at the Dietrich 75cc Extra 260 ARF (http://www.dietrichaircraft.com/75cc...ccExtra260.php)
It calls for servors with 180-330 ounce minimum of Torque. This is where I need help. Are there specific servos you all have had luck with that are over 330 ounces of torque???? Or would you recomend one of those pull pull devices that lines the servos up in a row and links them together? And if you link the servos together, what is the formula to determine the overall torque of the multiple servos in a row (do you just add the torque ratings together - meaning 2 150 ounce servos in a a row is 300? ounces?)???
Respectfully I am hoping to get some good facts on this.
thanks
10-28-2008 | 10:50 AM
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RE: Servo Torque - Please help!
*EDIT - I moved it to the correct forum for you.
Hi there.. you will get a better response in the Giant Scale 3D forum located here. http://www.rcuniverse.com/forum/forumid_110/tt.htm
The 2 servos of choice here will be the JR 8711 or the Hitec 7995,
Both are more than powerful enough for this plane. Their site seems to be down, so I cant tell if it used 2 servos per wing or one. If it uses 2 per wing than you can use 2 lesser torque servos and add them together to get the total amount of torque.
As a personal rule of thumb I always use the best servos I can afford... these servos can be rebuilt and transfered to even larger planes. For example you will see many using 3 of the mentioned servos per wing on a 41%er.
Hitec has Titanium gears and is programable.
JR centers a bit better and is slightly smoother.
Both are great servos.
Hi there.. you will get a better response in the Giant Scale 3D forum located here. http://www.rcuniverse.com/forum/forumid_110/tt.htm
The 2 servos of choice here will be the JR 8711 or the Hitec 7995,
Both are more than powerful enough for this plane. Their site seems to be down, so I cant tell if it used 2 servos per wing or one. If it uses 2 per wing than you can use 2 lesser torque servos and add them together to get the total amount of torque.
As a personal rule of thumb I always use the best servos I can afford... these servos can be rebuilt and transfered to even larger planes. For example you will see many using 3 of the mentioned servos per wing on a 41%er.
Hitec has Titanium gears and is programable.
JR centers a bit better and is slightly smoother.
Both are great servos.
10-30-2008 | 02:21 PM
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From: Merced, Ca.,
CA
RE: Servo Torque - Please help!
ORIGINAL: Jake Ruddy
*EDIT - I moved it to the correct forum for you.
Hi there.. you will get a better response in the Giant Scale 3D forum located here. http://www.rcuniverse.com/forum/forumid_110/tt.htm
The 2 servos of choice here will be the JR 8711 or the Hitec 7995,
Both are more than powerful enough for this plane. Their site seems to be down, so I cant tell if it used 2 servos per wing or one. If it uses 2 per wing than you can use 2 lesser torque servos and add them together to get the total amount of torque.
As a personal rule of thumb I always use the best servos I can afford... these servos can be rebuilt and transfered to even larger planes. For example you will see many using 3 of the mentioned servos per wing on a 41%er.
Hitec has Titanium gears and is programable.
JR centers a bit better and is slightly smoother.
Both are great servos.
I gotta second Jakes recommendation!!!! ENJOY
*EDIT - I moved it to the correct forum for you.
Hi there.. you will get a better response in the Giant Scale 3D forum located here. http://www.rcuniverse.com/forum/forumid_110/tt.htm
The 2 servos of choice here will be the JR 8711 or the Hitec 7995,
Both are more than powerful enough for this plane. Their site seems to be down, so I cant tell if it used 2 servos per wing or one. If it uses 2 per wing than you can use 2 lesser torque servos and add them together to get the total amount of torque.
As a personal rule of thumb I always use the best servos I can afford... these servos can be rebuilt and transfered to even larger planes. For example you will see many using 3 of the mentioned servos per wing on a 41%er.
Hitec has Titanium gears and is programable.
JR centers a bit better and is slightly smoother.
Both are great servos.
I gotta second Jakes recommendation!!!! ENJOY
10-31-2008 | 10:21 AM
#4
RE: Servo Torque - Please help!
I've flown several 50cc class birds and find that min of 200oz on rudder is needed to hold a KE. I'm in process of building a QQ 102" Yak and plan to gang up 2 hitec 7955 for that massive rudder for KE loop authority. I talked to Quique about your question, and he personally likes to use one big torque servo like the JR 8711 that puts out 400oz rather than gang up 2 smaller torque servos and have to match them. My feeling is if you already have 2 lesser servos to use on the rudder, then gang them up. But if you have to buy new, then get that JR8711 and you'll be set. For elevators, you'll also need about 250oz each side. That's my 2 cents.
10-31-2008 | 11:18 AM
#5
Senior Member
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RE: Servo Torque - Please help!
There are many high quality servos that will meet your needs from every one of the major manufacturers. Take a few moments to visit their sites to easily locate the ones that have the torque and speed to meet your needs. Also consider gear types since that will influence longevity. At this point in market/product development I prefer the Hitec 59 and 79 series and Futaba servos. Futaba being my personal choice of "best" with the electronics and accuracy with Hitec having a bullet proof gear train with a little less accuracy. The JR 86 and 87 series servos are initially very, very good.
Set any of them up correctly and you won't have any problems.
Set any of them up correctly and you won't have any problems.
11-04-2008 | 02:24 PM
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RE: Servo Torque - Please help!
A little overkill for the intended application but definately one to consider for larger and more demanding aircraft. Somethi ng that has not been addressed much so far is analog versus digital servos. Digitals are typically more accurate, have greater holding power, and develop their rated torque almost immediately. Analog servos have to travel farther in their sweep to reah full torque and are generally less accurate in resolution and centering but work well in many situations. If cost is a factor, and it usually is, if your not ganging servos the better metal geared analogs may serve you well.
11-04-2008 | 04:24 PM
#10
RE: Servo Torque - Please help!
TBM (Troy Built Models) has great info on servo test results, which can be dramatically different than manufacturer marketing numbers. In fact, I built a servos test stand like theirs to verify my own servos performance. I was surprised to find that Hitec 7955 puts out only 260oz of torque, as did TBM, and not nearly the 333oz that they advertised. But the Futaba and Hobbico servos got much closer to their rated numbers. Very interesting finding indeed.
