Which servo where?
05-01-2004, 07:36 AM
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Which servo where?
Hello,
I just bought a Monocoupe. 82" wing, 10 lbs, flies slow.
I have 4 servos at 57 oz/in and 2 at 49 oz/in.
Where should I use the lower torque servos?
It requires 2 aileron, 2 flaps, 1 rudder, 1 elevator.
For that matter could someone tell me which control surfaces typically receive the least load and which ones receive the highest load?
edit: corrected weight
I just bought a Monocoupe. 82" wing, 10 lbs, flies slow.
I have 4 servos at 57 oz/in and 2 at 49 oz/in.
Where should I use the lower torque servos?
It requires 2 aileron, 2 flaps, 1 rudder, 1 elevator.
For that matter could someone tell me which control surfaces typically receive the least load and which ones receive the highest load?
edit: corrected weight
05-01-2004, 07:55 AM
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RE: Which servo where?
You're in "giant" territory here, so "giant" principles apply, and I'm a little skeptical of your anticipated weight because you're in the size class of a pretty big glo engine or better yet, a G-23 class gas engine. But I'll do what I can...
First of all, you don't have enough servos.
Starting with what you have, I'd recommend:
Putting a 57oz servo on EACH elevator half.
Us one of the 49oz servos for throttle (no reason to waste a good servo).
Save the other 49oz servo for another airplane.
NOW, go out and get two 80oz+ servos, and put ONE ON EACH aileron.
Then, get a 120oz+ servo and put it on the rudder.
Go fly.
If you don't take advice well, don't want to buy any more servos, and like to live dangerously, drive both ailerons with a 57oz servo, the elevator (both halves) with the other 57oz servo, a 49oz servo on the rudder, and the other 49oz servo on the throttle.
Go crash.
Highflight
First of all, you don't have enough servos.
Starting with what you have, I'd recommend:
Putting a 57oz servo on EACH elevator half.
Us one of the 49oz servos for throttle (no reason to waste a good servo).
Save the other 49oz servo for another airplane.
NOW, go out and get two 80oz+ servos, and put ONE ON EACH aileron.
Then, get a 120oz+ servo and put it on the rudder.
Go fly.
If you don't take advice well, don't want to buy any more servos, and like to live dangerously, drive both ailerons with a 57oz servo, the elevator (both halves) with the other 57oz servo, a 49oz servo on the rudder, and the other 49oz servo on the throttle.
Go crash.
Highflight
ORIGINAL: yukondog
Hello,
I just bought a Monocoupe. 82" wing, 10 lbs, flies slow.
I have 4 servos at 57 oz/in and 2 at 49 oz/in.
Where should I use the lower torque servos?
It requires 2 aileron, 2 flaps, 1 rudder, 1 elevator.
For that matter could someone tell me which control surfaces typically receive the least load and which ones receive the highest load?
edit: corrected weight
Hello,
I just bought a Monocoupe. 82" wing, 10 lbs, flies slow.
I have 4 servos at 57 oz/in and 2 at 49 oz/in.
Where should I use the lower torque servos?
It requires 2 aileron, 2 flaps, 1 rudder, 1 elevator.
For that matter could someone tell me which control surfaces typically receive the least load and which ones receive the highest load?
edit: corrected weight
05-01-2004, 09:12 AM
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RE: Which servo where?
No thanks. It cost too much to crash. Thanks for the good advice. Yes, I do take advice well. Thats why I asked.
I left you with the wrong impression of the Monocoupe.
http://www.hobby-lobby.com/monocoupe.htm
Hobby Lobby recommends Hitec hs-422 servos. I have 4 hs-425BB and 2 hs-322HD.
Please look at the airplane on the above site and let me know if your large scale advice still applies.
I hope you don't crash.
I left you with the wrong impression of the Monocoupe.
http://www.hobby-lobby.com/monocoupe.htm
Hobby Lobby recommends Hitec hs-422 servos. I have 4 hs-425BB and 2 hs-322HD.
Please look at the airplane on the above site and let me know if your large scale advice still applies.
I hope you don't crash.
05-01-2004, 06:43 PM
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RE: Which servo where?
Well, being electric and therefore not terribly over powered for airbatics, you may do well with the second scenario for your servos as noted in the previous post. However, I would maintain a mental attitude that you're flying an airplane in the class of a Telemaster where you're just toolin' around doing nice gentle flying with maybe an occasional loop, but forget messing with extreme airbatics. Those servos you have won't take it for very long.
That said, here's something to keep in mind: You know how you will occasionally read a thread where someone complains that the (insert any brand name of servo here) servos they are using are junk because they strip gears "real easy"?
Well, pay attention to the application they are using them for and you will soon see that they are typically installing servos for uses that really should require more torque, and in the end, their servo stripping problems are usually their own fault.
Here's a simple example: Say you put a 47oz servo on your elevator of a 10 pound aircraft. The normal flight loads of gentle flight may be fine for a servo of that torque, but on a hard landing when the tail slams onto the runway, or during hard airbatics, that large elevator can be "whipped" up or down with a force that far exceeds the forces than what that servo normally sees in flight. That's simple physics and comes from the size and weight of the flying surface causing enertial and momentum forces way beyond that of the resistance of the airstream itself. Oh jeez, I think I just gave myself a headache.
That's what I meant when I said that "giant principles apply", i.e., the larger and heavier control surfaces of larger aircraft (independant of the overall weight of the aircraft itself) add forces way beyond the simple and anticipated airstream resistance.
So if you're setting up a large aircraft, and you think you are using a servo that is "just" torquey enough, then you probably NEED to go another step up in torque.
The bottom line is that when you get to airplanes around 72in. wingspan or larger, there is almost no penalty in weight for using a torqueir ('zat a word?) servo because nowadays, you can get 100oz+ servos that are in the same case size and weight as standard 45oz servos.
So if you're going to error, I'd say error on the high side.
I'm not going to tell you not to use the servos you have for that Monocoupe because they may be fine, but like I said, don't ask the aircraft to do anything especially vigorous.
Highflight
That said, here's something to keep in mind: You know how you will occasionally read a thread where someone complains that the (insert any brand name of servo here) servos they are using are junk because they strip gears "real easy"?
Well, pay attention to the application they are using them for and you will soon see that they are typically installing servos for uses that really should require more torque, and in the end, their servo stripping problems are usually their own fault.
Here's a simple example: Say you put a 47oz servo on your elevator of a 10 pound aircraft. The normal flight loads of gentle flight may be fine for a servo of that torque, but on a hard landing when the tail slams onto the runway, or during hard airbatics, that large elevator can be "whipped" up or down with a force that far exceeds the forces than what that servo normally sees in flight. That's simple physics and comes from the size and weight of the flying surface causing enertial and momentum forces way beyond that of the resistance of the airstream itself. Oh jeez, I think I just gave myself a headache.
That's what I meant when I said that "giant principles apply", i.e., the larger and heavier control surfaces of larger aircraft (independant of the overall weight of the aircraft itself) add forces way beyond the simple and anticipated airstream resistance.
So if you're setting up a large aircraft, and you think you are using a servo that is "just" torquey enough, then you probably NEED to go another step up in torque.
The bottom line is that when you get to airplanes around 72in. wingspan or larger, there is almost no penalty in weight for using a torqueir ('zat a word?) servo because nowadays, you can get 100oz+ servos that are in the same case size and weight as standard 45oz servos.
So if you're going to error, I'd say error on the high side.
I'm not going to tell you not to use the servos you have for that Monocoupe because they may be fine, but like I said, don't ask the aircraft to do anything especially vigorous.
Highflight
05-01-2004, 09:57 PM
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RE: Which servo where?
OK, I'm convinced. I'd rather buy another $200 worth of servos than risk it.
Thanks again.
By the way, the new ones I ordered are much torqueir. Twice more and only .2 oz heavier.
Anyone want to buy 6 unused standard servos?
Thanks again.
By the way, the new ones I ordered are much torqueir. Twice more and only .2 oz heavier.
Anyone want to buy 6 unused standard servos?
