V-Tail Linkage Tip
01-21-2008, 08:28 PM
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V-Tail Linkage Tip
Been working on a few planes the last month, and thought I'd share a tip that I've mentioned a few times, but never really documented it well.
When I build a quickie with a V-tail, I use 1/8" carbon fiber tube as my pushrods. It is available several places, and the center of the tube is a slip fit for 2/56 rod.
Before I glue anything into the carbon, I take a piece of 2/56 rod and wet it with a paper towel lightly soaked in Alcohol (the non-drinking kind) and slowly push it in and out of the tube to clean any debris. When I glue rod into Carbon, I use 5 minute epoxy, and have never had a failure. You just gotta be carefull that you get enough glue into the rod, it is a pretty snug fit.
The end that is attached to the V-tail halves can't be seen in the pictures, but I take a 2" piece of 2/56 rod with about 1/2" of thread on one end and glue it into the carbon rod. Once you push the glue incaased rod in, slightly turn the rod a couple times (clockwise) and this buries about an 1/8" of thread inside the tube. If you turn it too many times, the rod can crack/splinter and you do not want to do that. I then attached a dubro ball link to the threas and popped it on the ball that connects to the torque rods of my V-tail.
In Picture #1 I have my two Servos mounted (JR Sport MN-48s), they are plugged into a receiver, the transmitter is on, and the servos are perfectly centered. I am testing these servos for our local OS .46 class in 2008, I'm not sure I would trust them with a Nelson powered plane, but will start at 125 mph and go from there. At $22, 48 oz torque, and less than ounce, they seem like a good fit for V-tail servos.
In Picture #2 I attached 4 lightweight clamps that hold the elevators in perfect neutral position.
In Picture #3 I show a paper towel draped under the pushrods. When you start to glue the rods into the carbon, there is always a little spooge out, and the paper towels catch it, so that it doesn't stick to the bottom of your fuse.
Picture #4 shows the rods glued into the carbon, the servos centered, and the servo arm screws in place. Once the glue is dry, I give it 10 minutes, I switch off the receiver and turn off the transmitter. Everything is perfectly centered without worrying about sub-trim, or mechanically adjusting it by twisting the rod and hoping the ball links twist at the torque rods without popping off.
When I build a quickie with a V-tail, I use 1/8" carbon fiber tube as my pushrods. It is available several places, and the center of the tube is a slip fit for 2/56 rod.
Before I glue anything into the carbon, I take a piece of 2/56 rod and wet it with a paper towel lightly soaked in Alcohol (the non-drinking kind) and slowly push it in and out of the tube to clean any debris. When I glue rod into Carbon, I use 5 minute epoxy, and have never had a failure. You just gotta be carefull that you get enough glue into the rod, it is a pretty snug fit.
The end that is attached to the V-tail halves can't be seen in the pictures, but I take a 2" piece of 2/56 rod with about 1/2" of thread on one end and glue it into the carbon rod. Once you push the glue incaased rod in, slightly turn the rod a couple times (clockwise) and this buries about an 1/8" of thread inside the tube. If you turn it too many times, the rod can crack/splinter and you do not want to do that. I then attached a dubro ball link to the threas and popped it on the ball that connects to the torque rods of my V-tail.
In Picture #1 I have my two Servos mounted (JR Sport MN-48s), they are plugged into a receiver, the transmitter is on, and the servos are perfectly centered. I am testing these servos for our local OS .46 class in 2008, I'm not sure I would trust them with a Nelson powered plane, but will start at 125 mph and go from there. At $22, 48 oz torque, and less than ounce, they seem like a good fit for V-tail servos.
In Picture #2 I attached 4 lightweight clamps that hold the elevators in perfect neutral position.
In Picture #3 I show a paper towel draped under the pushrods. When you start to glue the rods into the carbon, there is always a little spooge out, and the paper towels catch it, so that it doesn't stick to the bottom of your fuse.
Picture #4 shows the rods glued into the carbon, the servos centered, and the servo arm screws in place. Once the glue is dry, I give it 10 minutes, I switch off the receiver and turn off the transmitter. Everything is perfectly centered without worrying about sub-trim, or mechanically adjusting it by twisting the rod and hoping the ball links twist at the torque rods without popping off.
02-04-2008, 09:54 AM
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RE: V-Tail Linkage Tip
spooge? that's a new word on me...
Dave, this is a great writeup. I've used carbon fiber tubes (like you, I use the 1/8") on the last couple of airplanes, and it would be tough to go back to something else.
What do you think of those MN48's?
Dave, this is a great writeup. I've used carbon fiber tubes (like you, I use the 1/8") on the last couple of airplanes, and it would be tough to go back to something else.
What do you think of those MN48's?
02-04-2008, 10:56 AM
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RE: V-Tail Linkage Tip
Not real sure on the MN-48's yet. It looks like they are what replaced the Expert SL-451 servo I had used in Sport 424 type racing on my v-tails. If they are similar, I am happy with them for a $22 servo. I don't think I would use one on Aileron, or for Q40's, but for a v-tail on slower race planes, they should work fine.
02-04-2008, 02:21 PM
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RE: V-Tail Linkage Tip
I use the same basic setup, but substitute Flex CA for the 5 minute epoxy. A guy on another forum turned me on to this. To test it he actually hamered the glued in end into a pine block. The carbon tube splintered before the glued end broke free.
02-04-2008, 02:38 PM
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RE: V-Tail Linkage Tip
Chris,
Is the glue you use similar to black flash, ruberized CA, or tire glue? I've used that in the past, and it works fine just less time to get everything lined up perfect. Also, I didn't use that type of glue very often and it tended to go bad relatively quick after opening.
Is the glue you use similar to black flash, ruberized CA, or tire glue? I've used that in the past, and it works fine just less time to get everything lined up perfect. Also, I didn't use that type of glue very often and it tended to go bad relatively quick after opening.
02-04-2008, 10:54 PM
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RE: V-Tail Linkage Tip
Dave , I had a salesman at horizon tell me that the MN48 is in fact the same servo as the expert sl 451 , just with JR's name on it.
02-05-2008, 06:58 AM
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RE: V-Tail Linkage Tip
ORIGINAL: PylonDave
Dave , I had a salesman at horizon tell me that the MN48 is in fact the same servo as the expert sl 451 , just with JR's name on it.
Dave , I had a salesman at horizon tell me that the MN48 is in fact the same servo as the expert sl 451 , just with JR's name on it.
02-05-2008, 11:12 AM
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RE: V-Tail Linkage Tip
I used them on a 428 all last year.
Although one of the original MN48s went bad after a couple of flights . I replaced it with another one and have had no problems since.
Although one of the original MN48s went bad after a couple of flights . I replaced it with another one and have had no problems since.
02-05-2008, 11:28 AM
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RE: V-Tail Linkage Tip
Dave,
Yes, it's the rubberized CA. The bottle I have says "Flex CA". I've been beating on the set I made for my OMP Edge doing Blenders and similar tricks and they're holding up great. Matter of fact the ball links are getting sloppy from the vibration of the Saito 82. I'll probably have to replace the ball links this season, but the rods will remain the same.
Chris
Yes, it's the rubberized CA. The bottle I have says "Flex CA". I've been beating on the set I made for my OMP Edge doing Blenders and similar tricks and they're holding up great. Matter of fact the ball links are getting sloppy from the vibration of the Saito 82. I'll probably have to replace the ball links this season, but the rods will remain the same.
Chris
