Ds Jr8411
12-19-2002, 11:50 PM
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Ds Jr8411
your going to have to get the matchboxes because thats the only way you can line up your servos correctly without having them fight each other... i think there 20$ a piece at chiefaircraft.com
12-20-2002, 04:24 AM
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Ds Jr8411
This smell like a conspiracy!! 
Propogation of the product line. If you buy this, then your gonna need to buy that, and if you buy that, then your for sure better get them........
Sorry, Bad day. Rant mode off.......
Cheers!
Propogation of the product line. If you buy this, then your gonna need to buy that, and if you buy that, then your for sure better get them........
Sorry, Bad day. Rant mode off.......
Cheers!
12-20-2002, 04:28 AM
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Ds Jr8411
If your needing this centering for the rudder, why not just use a floating tiller? Safer, no fighting of servos, if one servo goes away there is no significant loss of rudder control. Better than making JR even richer on another electronic device that can fail. I'm not really knocking JR, I use them and like them, but I'm not going to get sucked all the way into their lair.
Cheers!
Cheers!
12-20-2002, 02:10 PM
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Ds Jr8411
Couple options.
Build a 12" pointer arm, and make a table servo mount. Label each servo, and mount them one at a time on the table mount. Write down the centering, and each end point. Then match them in threes for each aileron. With 15 servos, you should be able to find two groups of three that match up well. Use them for the ailerons. If you can't get two groups of three, a match box for each aileron is probably your next best bet.
Using separate channels for multiple servos. Unfortunately, unless you can afford 6 channels for the ailerons, you can't use this approach. you could use two channels for each aileron, where one channel has one servo, and the other channel has 2 matched servos. I would work fine, but you would still need 4 channels just for the ailerons.
Splitting the ailerons is another option, and works perfectly with 2 servos per aileron. It solves lots of issues with binding, and you get a large bump in reliability and redundancy. However, an aileron split into three separate pieces looks like a hack, even though its a very good option to use.
A note with the matchbox approach. You are adding more connections, each with its own voltage drop properties and increased failure rates. The connectors are probably your biggest thieves of voltage to your servos. Unfortunately, thats what the matchbox offers, so try to use larger wire, and limit any other connections in those leads. Keep the matchbox close to the servos if possible.
Most people I know buy enough JR8411's to get good matches for each group of three. The remaining ones are used for other surfaces, or go into stock for the next airplane. Its an expensive way to go, but no on said these planes were inexpensive at $6K a pop
You do what you got to do!
Fly wild, be safe, have fun.
Build a 12" pointer arm, and make a table servo mount. Label each servo, and mount them one at a time on the table mount. Write down the centering, and each end point. Then match them in threes for each aileron. With 15 servos, you should be able to find two groups of three that match up well. Use them for the ailerons. If you can't get two groups of three, a match box for each aileron is probably your next best bet.
Using separate channels for multiple servos. Unfortunately, unless you can afford 6 channels for the ailerons, you can't use this approach. you could use two channels for each aileron, where one channel has one servo, and the other channel has 2 matched servos. I would work fine, but you would still need 4 channels just for the ailerons.
Splitting the ailerons is another option, and works perfectly with 2 servos per aileron. It solves lots of issues with binding, and you get a large bump in reliability and redundancy. However, an aileron split into three separate pieces looks like a hack, even though its a very good option to use.
A note with the matchbox approach. You are adding more connections, each with its own voltage drop properties and increased failure rates. The connectors are probably your biggest thieves of voltage to your servos. Unfortunately, thats what the matchbox offers, so try to use larger wire, and limit any other connections in those leads. Keep the matchbox close to the servos if possible.
Most people I know buy enough JR8411's to get good matches for each group of three. The remaining ones are used for other surfaces, or go into stock for the next airplane. Its an expensive way to go, but no on said these planes were inexpensive at $6K a pop
You do what you got to do!Fly wild, be safe, have fun.
12-20-2002, 02:23 PM
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Ds Jr8411
Thanks for your input stephen.
I wil find the servos which matches and use the worst ones on the RUDDER, because im getting a matchbox there.
Thanks for the info one more time
I wil find the servos which matches and use the worst ones on the RUDDER, because im getting a matchbox there.
Thanks for the info one more time
12-21-2002, 05:54 PM
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Ds Jr8411
I know this is possible. But how did all the "Pros" use JR digital servos before match boxes were brought out.
I know somebody that has a 1/3H9 suk, and 40% extra running all 8411's and there isn't a matchbox in either plane.
He is also having 2 other 35% and bigger planes build and there won't be a match box in them either. so I know is possible. But I don't know how it's done.
He dosn't know either because he pays somebody to set up his planes for him.
He using a 10X radio. so that might be the solution.
I know somebody that has a 1/3H9 suk, and 40% extra running all 8411's and there isn't a matchbox in either plane.
He is also having 2 other 35% and bigger planes build and there won't be a match box in them either. so I know is possible. But I don't know how it's done.
He dosn't know either because he pays somebody to set up his planes for him.
He using a 10X radio. so that might be the solution.
12-21-2002, 06:12 PM
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Ds Jr8411
Originally posted by m.gramling
I know this is possible. But how did all the "Pros" use JR digital servos before match boxes were brought out.
I know somebody that has a 1/3H9 suk, and 40% extra running all 8411's and there isn't a matchbox in either plane.
He is also having 2 other 35% and bigger planes build and there won't be a match box in them either. so I know is possible. But I don't know how it's done.
He dosn't know either because he pays somebody to set up his planes for him.
He using a 10X radio. so that might be the solution.
I know this is possible. But how did all the "Pros" use JR digital servos before match boxes were brought out.
I know somebody that has a 1/3H9 suk, and 40% extra running all 8411's and there isn't a matchbox in either plane.
He is also having 2 other 35% and bigger planes build and there won't be a match box in them either. so I know is possible. But I don't know how it's done.
He dosn't know either because he pays somebody to set up his planes for him.
He using a 10X radio. so that might be the solution.
1. Match each servo individual for the closest neutral and end points, then gang them together on the same surface.
2. Use individual channels for each servos, which then allows you to use the mixing and programming in the transmitter to perform the same function as a matchbox.
3. Use a match box to provide the ability to electronically match the neutral and end points.
4. Split the surface into two parts (ie, for a 2 servos on one aileron) so that each servo controls half of the aileron. Then match them as best you can mechanically. (Doing #1. is also important with this option).
These are the most common arrangements I am familiar with.
12-21-2002, 06:27 PM
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Ds Jr8411
Originally posted by Shortman
ads? i just asked him what the servos were going into??? read more carefully next time
ads? i just asked him what the servos were going into??? read more carefully next time
Daniel D.
12-31-2002, 10:25 AM
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Kasper
To address your comment on the ailerons and using matchboxes there. If as stated you can match the servos to each other the best you can, and then switch and swap all of your arms the best you can, and then, Yes, do your geometry homework the best you can on the linkages, usually the spacing of the ailerons servos lends itself less to the problems of gang fighting. Hopefully that makes sense, but the gyst of it is that usually the rudder servos are within less than an inch from one another, while the ailerons servos are several inches. They lose their attraction and ambition to fight at those distances. That has been my experience anyway. Take care_bob
