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split elevator problem
Finishing my second H9 corsair , measured everthing carefully before glueing the elevator halves to the stab but after it dried a test run on the ground appears to have one side with a slight differance then the othere when I move them up and down .
One side seems to trail . Any suggestions on how to fix this considering its all glued in ? If your not familar with the set up its a typical elevator set up , both sides get ca hinges to the stab and a medal long U type bracket hold both elevators even under power from one side driven by the servo |
RE: split elevator problem
Depending on the metal in that U bracket.........
And depending on the balsa that's in the elevator halves where that U is glued....... We've done years and years of this in CL stunt........ Grab each elevator exactly where the U arms run into the elevator and BEND a little. If you fear that you'll have the metal crush the wood too much (and that's a sensible fear) then cut out small holes toward the ends of the U and you'll have direct touch to the metal. Next down on the list of possible solutions is to take one elevator side and cut halfway through the bottom of it. The cuts follow the arm of the U. One cut on each side. You're actually going to free the metal arm enough to be able to change where it sits in the wood. Once it's somewhat free, adjust and glue it back solid. It's actually easy to do. Once glued, sand smooth and recover and nobody will be able to see a thing. And your plane will fly better for it. One method takes about 10 seconds. The other one takes about 10 minutes. |
RE: split elevator problem
ORIGINAL: darock Depending on the metal in that U bracket......... And depending on the balsa that's in the elevator halves where that U is glued....... We've done years and years of this in CL stunt........ Grab each elevator exactly where the U arms run into the elevator and BEND a little. If you fear that you'll have the metal crush the wood too much (and that's a sensible fear) then cut out small holes toward the ends of the U and you'll have direct touch to the metal. Next down on the list of possible solutions is to take one elevator side and cut halfway through the bottom of it. The cuts follow the arm of the U. One cut on each side. You're actually going to free the metal arm enough to be able to change where it sits in the wood. Once it's somewhat free, adjust and glue it back solid. It's actually easy to do. Once glued, sand smooth and recover and nobody will be able to see a thing. And your plane will fly better for it. One method takes about 10 seconds. The other one takes about 10 minutes. Using dual servos. Can't adjust servo travel at the end range individually. Can't adjust pushrod length because those adjustments would throw out the "neutral" position (which is aligned). That 1/16" difference is enough to throw off alignment in loops significantly. :?: |
RE: split elevator problem
voyager?
why would you use a wire joiner with a dual servo setup? If using dual servos, no joiner would be the best bet--that way one servo doesn't fight the other. Sounds a lot like a mechanical linkage issue. I know you say it doesn't, but one servo is indexed at a slightly different position than the other, and so the arc of one servo horn is slightly different than the arc of the other--giving more or less travel between the two. The travel arc's of the servos need to be exactly the same, if possible. Try removing one arm, and re-indexing it with the reversing Y's adjustment. Then, replace the arm. The arm's of both servos need to be in exactly the same relative position at neutral. If this still doens't fix the problem, then you might have to use something like a matchbox or other electronic mixer to fix the problem--assuming you cannot split the elevator servo's onto different channels and slave them in your radio. |
RE: split elevator problem
Lets get the terminology straight first.:eek:
The metal "U" is called a torque rod. CUT the torque rod in half with a dremel tool. Or, get a pair of sidecutters or linemans pliers and snip the torque rod in half. Whatever it takes--cut the darn thing in half and disable it. That will allow each elevator to move independant of the other. Now install a control horn on BOTH elevators. Run a linkage from each elevator up to the servo. Solder/braze the linkages together so that you only have 1 rod to connect up to the servo. Use a single clevis or connector to hook up the linkage to the servo. Use the threads on the ends of the rods to adjust the elevators. Screw the clevis' in and out untill both elevators line up. |
RE: split elevator problem
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ORIGINAL: LDM Finishing my second H9 corsair , measured everthing carefully before glueing the elevator halves to the stab but after it dried a test run on the ground appears to have one side with a slight differance then the othere when I move them up and down . I like to use Sig heavy duty elevator joiner, part #SIGSH554: [link]http://www.sigmfg.com/cgi-bin/dpsmart.exe/DetailProduct.html?L+Sig+mnvh0519+_Dimagefile_02SI GSH554_2ehtml_01[/link] It has a single internal control horn so torque is split evenly between the two elevator halves. My H9 Corsair has it and my TF Corsair has it. |
RE: split elevator problem
Rich I think your answer hits it on the head , did you put your elevator servo in the fuse ?
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RE: split elevator problem
My situation is more different than originally described. Sorry for any confusion. I think what I need to do is figure out why it's off before I can figure out how to correct it.
The plane was bought in an estate sale. The builder (electronics guy) wired the servo's in through a circuit board that controls (reverses) the servos. It may be that the servo placement is slightly off so at rest they are neutral but when activated, the angle is ever so slightly off at full deflection. I have more research to do b4 I can actually post here. |
RE: split elevator problem
ORIGINAL: LDM Rich I think your answer hits it on the head , did you put your elevator servo in the fuse ? |
RE: split elevator problem
ORIGINAL: voyager_663rd The plane was bought in an estate sale. The builder (electronics guy) wired the servo's in through a circuit board that controls (reverses) the servos. It may be that the servo placement is slightly off so at rest they are neutral but when activated, the angle is ever so slightly off at full deflection. I have more research to do b4 I can actually post here. Servos don't travel the same amount in both directions. Any given servo will travel--lets say 50 degrees clockwise and only 45 degrees counter-clockwise. When you reverse 1 servo with a servo reverser--then they are always going to travel different amounts. 1 is traveling 50 degrees and the other is traveling only 45 degrees. Thats why--even though they may be centered up together when at neutral--you see different amount of elevator movement at full deflection. The only way to get it right is to use a JR Matchbox, Smart-Fly Equalizer, Futaba Servo Synchroniser, or a TX that can do the mixing for you. |
RE: split elevator problem
At this point , I have a full interior in the plane so the servo in the fuse will be some work and th elevator is totally glued in .
I may have a simple fix . The rear fuse is solid wood . I can drill a curved arch(similar to the maximum travel of the Elevator) in the rear fuse at the tips of the rear elevator . Then expozy a small carbon fiber rod attaching both ends of the elevator and ensuring they are 100% level prior to adhesion .The rod would travel in the drilled out arch with the movement of the elevator . This should be able to hold both ends even and give good solid even control . What do you guys this about that ? [X(] |
RE: split elevator problem
Actually, torque rods are used in single servo ailerons--they convert linear motion into angular motion--linear motion of the push rod to angular motion of the ailerons. For joining elevator halves, you'd use a joiner wire--this is the terminology used in every kit I've ever put together.....
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RE: split elevator problem
I stand corrected.;)
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RE: split elevator problem
Why not convert the whole system for theelevators to a pull pull system, 4 wires , 2 for up elevator and 2 for down elevator, that way you can set the elevators exactly, using one servo
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