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Servo reverser in a Gas airplane?

Old 12-27-2013, 12:13 PM
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av8tor1977
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Default Servo reverser in a Gas airplane?

I am hoping to be allowed this somewhat off topic post because the only radio forums are manufacturer support only, and this is not a manufacturer specific question.

I have a servo reverser on one of the elevator servos in my Giles 202 with a 30cc gas engine. The reason I have it is because if I do a program mix in the transmitter with this particular setup and set up both servos to work together, the trim only trims one of the elevators. So I use only one channel for the elevators, and a servo reverser on one of the elevator servos. However, and this is a known problem with the reverser I used, the servo changes it's center along with changes in temperature. When it is cool in the house, the elevators are not aligned. When I take the plane out and let it sit in the sun and warm up for a bit, the center slowly changes until the elevators are once again aligned as I had set them. Sometimes you can actually watch the elevator half move as the reverser warms up.

Now, the question I have is some time ago I bought a World Experts servo reverser to install to hopefully fix this problem. It is supposed to be a better servo reverser unit. Does anyone know if it is a good unit and/or if it has any known problems. Is it reliable?

Please note that I know about JR and Futaba servos being reversed to one another respectively, and I know how to dis-assemble a servo and reverse it. I have done both in the past. In this case I would rather just plug in the World Expert servo reverser if that will be a reliable course of action.

Thanks in advance for any info,
AV8TOR
Old 12-27-2013, 04:42 PM
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tkg
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World Expert has been gone for 15 years, you sure you want that reverser in your plane? I think its solidering time:
Old 12-27-2013, 05:15 PM
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First, I would try and work out the mix issue. I had a similar issue using Futaba and I solved it in the programming,,,,just have to remember what I did. Either blanking out the slave channel or using a different receiver channel as the slave.
Second if I couldn't get the programming solved I would reverse the servo wiring before using the Expert box. As stated , that has been around for awhile and may not be reliable now.
Old 12-27-2013, 05:53 PM
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av8tor1977
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Well, here is what Futaba has to say about it with this system, so that verifies that it is impossible to get trim support with this 6XAS system on a mix. So, it is either take a chance with the World Expert servo reverser, or do electronic surgery.

(FUTABA QUOTE): How can I operate dual elevator or rudder servos using the 6X? While this is possible, as briefly described in the 6X manual, it is not ideal. This entry level computer radio cannot offer you trim support from a mix, so using the trimmer on your radio would trim only the servo, for example, on channel 2, not that on channel 6, which would be a real problem. Also, the elevator dual rate switch MUST be on at all times or the mix is turned off and your model will, very likely, crash.


If I wasn't so cheap, I would just buy a receiver for the plane to use with my Hitec Aurora 9 huh? (LOVE that radio!)

AV8TOR
Old 12-27-2013, 10:36 PM
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bcchi
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Originally Posted by av8tor1977 View Post
I am hoping to be allowed this somewhat off topic post because the only radio forums are manufacturer support only, and this is not a manufacturer specific question.

I have a servo reverser on one of the elevator servos in my Giles 202 with a 30cc gas engine. The reason I have it is because if I do a program mix in the transmitter with this particular setup and set up both servos to work together, the trim only trims one of the elevators. So I use only one channel for the elevators, and a servo reverser on one of the elevator servos. However, and this is a known problem with the reverser I used, the servo changes it's center along with changes in temperature. When it is cool in the house, the elevators are not aligned. When I take the plane out and let it sit in the sun and warm up for a bit, the center slowly changes until the elevators are once again aligned as I had set them. Sometimes you can actually watch the elevator half move as the reverser warms up.

Now, the question I have is some time ago I bought a World Experts servo reverser to install to hopefully fix this problem. It is supposed to be a better servo reverser unit. Does anyone know if it is a good unit and/or if it has any known problems. Is it reliable?

Please note that I know about JR and Futaba servos being reversed to one another respectively, and I know how to dis-assemble a servo and reverse it. I have done both in the past. In this case I would rather just plug in the World Expert servo reverser if that will be a reliable course of action.

Thanks in advance for any info,
AV8TOR
What radio are you useing. This should be a program already in your radio if modern.
Grump no Two.BC
Old 12-27-2013, 11:52 PM
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av8tor1977
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It is a Futaba 6XAS. Manual trims. The quote I put is directly from Futaba. You can program a mix, but the trim will not work on both channels; only the master channel. PITA! I found this out when I first started using this radio, that's why this plane got a servo reverser put in it when I built it years ago instead of using a program mix like I do with all my other equipment. (I have a Futaba 7CAP and a Hitec Aurora 9 also) Neither of those have this trim problem with mixes.

AV8TOR
Old 12-28-2013, 05:34 AM
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coralcape
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How about moving one servo arm 180deg. red
Old 12-28-2013, 06:56 AM
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av8tor1977
I have ran into the same issue using the same Radio, If there is enough room I will turn the servo around and put the arm on the other side and remake the linkage hookup. I'm not sure about world expert products, but my local hobby store has an Expert line of servos extensions and reverser's, that I like better than the JR line they carry. I have use all of them with good luck in several smaller glow planes, but only one 30CC gas plane. It's fore sure I would change out the one you have now for another and see if things stay in line better. There is also another option the better grade of Hitec servos are programmable and can be reversed fairy easy, but a person has to have the servos and a programmer to do so.
Good luck either way you go.
Old 12-28-2013, 10:32 AM
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Get you a matchbox.. Problem solved..
Old 12-28-2013, 11:39 AM
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av8tor1977
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Wow, 70 bucks for a Matchbox?? Nope, I'll reverse the servo myself before spending that kind of money to do a simple job, but thanks for the idea.

The reason I don't switch the servo arm 180 degrees is that then the two elevator servos will have different connection geometry and won't work perfectly symmetrical. Talk about a trimming nightmare...!

AV8TOR
Old 12-28-2013, 11:49 AM
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acerc
 
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Sounds to me like you already know the answer to your question but was hoping someone knew something you did not. But it would appear you know what you have to do.
Old 12-28-2013, 11:52 AM
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flyinwalenda
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I see now that radio is a bit limited in programming. As far as the reverser, even if it's the newer Expert "Y" harness reverser and not a 20yo box I still wouldn't trust it. Ive had two of those "Y" reversers fail on me in the past and I've seen a few other folks use them and have them fail also. That's why I just reverse the servos now. The good thing is that when the reversers failed they just didn't work and the control surface stayed neutral instead of failing in the up or down position. For split elevator, if it fails in the neutral position you can still land the plane using the other elevator half. Not sure how much fun it would be if it locked in the up or down position ! Still, I would open the servo ,swap the two wires and be done with it !

Last edited by flyinwalenda; 12-28-2013 at 11:55 AM.
Old 12-28-2013, 11:55 AM
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av8tor1977
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Yeah well, I was hoping to hear several replies saying "Oh yeah, I've used that World Experts servo reverser for years with NO problems." Then I would have put it in the plane and taken it flying. But, no such luck so I will remove, disassemble, and reverse the servo. Usually I am the one that hates potentially disastrous single failure points but I was being lazy this time.....

Anyone want to buy a new in the package World Experts servo reverser?? Tee hee....

AV8TOR

Last edited by av8tor1977; 12-28-2013 at 12:04 PM.
Old 12-28-2013, 12:14 PM
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flyinwalenda
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I've never used the Expert reverser ,I don't remember who made the ones I used. I was generally speaking about all of them. Maybe the Expert one is solid but I wouldn't trust it, especially in a nice plane.
Old 12-28-2013, 02:16 PM
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TheRickster
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Yea, new they are 70 bucks and that is a hard pill to swallow just to reverse and be able to have a trim function... You can pick up used Futaba 9CAP's for around 150.00 bucks and then you will have all the programming you would need...
Old 12-28-2013, 04:08 PM
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av8tor1977
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Cheaper yet to just buy another receiver for my Hitec Aurora 9 and put the plane on that radio. Cheaper than that, change the crystal to the channel of my Futaba 7CAP and use it's more advanced programming to do what I want. I was just hoping to use the "new in package" World Expert servo reverser that I had bought a long time ago to solve the problem with a simple disconnect/re-connect process. Guess not...

Thanks for the answers guys!
AV8TOR
Old 12-28-2013, 05:22 PM
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My vote would be to go for a quick solder job...
Old 12-28-2013, 05:45 PM
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A couple years back I put together this nice GP Ultimate. It was an ARF but hey it was cheap, so I bought it and commenced to installing stuff I already had including a 55cc DLE. Same as many guys, servos from this drawer, batteries from that drawer, accessories from here and there. Second flight in a servo shorted out, drained all the juice in seconds, and she came crashing down. Upon inspection I found the throttle servo was toasted, that one was a JR from the drawer full of got it here and there. I went home and pulled all my drawers out to the trash can and sent them on their way. No matter whom is offering what I will not put a used anything in my airframes. That used/old servo cost me not only that good deal but because I liked the Ultimate so well I bought another three days later. Never again with used or old for this old man.
Old 12-28-2013, 06:53 PM
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Ace, I learned that lesson the hard way myself! I still use some used equipment from time to time but only if I know its history and that it can be trusted. Anything in doubt ... give it away or trash it. Nothing good ever comes from using an old servo, switch, battery, etc.
Old 12-28-2013, 09:01 PM
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if you have newer servos with surface mounted components good luck reversing the servo by switching the motor and pot leads.
Old 12-29-2013, 04:58 AM
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Dionysus design servo reverser. About $12. They work great and very reliable.
Old 12-29-2013, 05:59 AM
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You state exactly why I won't use servo reversers - electronic imbalance between the two sides is worse than just using a y harness and placing the servos correctly. Since you are tlaking about spending money on another reverser just buy another receiver and get rid of that radio. Being cheap now will cost you later.
Old 12-29-2013, 09:06 AM
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Your talking exactly why I sold one of my 6xa's with the plane complete and gave the other one away, My Hitec eclipse 7 has a simular issue but since it's synthesis I keep it around and fly most of my good glow models on it.
I also understand the hassle of setting up the linkage geometry when changing around a servo, but it can be done W/O all that much effort, a person just needs to use good hardware that won't flex, plus remember that the servo arms won't away's be the same exact length.
I had forgot all about Match boxes I think I have about 4 of them unused at the moment with no plans of use in the future. That's providing that I have not already gave them away to someone. If I remember right they also had a slight centering issue too.
Old 12-29-2013, 11:54 AM
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Originally Posted by av8tor1977 View Post
Cheaper yet to just buy another receiver for my Hitec Aurora 9 and put the plane on that radio. Cheaper than that, change the crystal to the channel of my Futaba 7CAP and use it's more advanced programming to do what I want. I was just hoping to use the "new in package" World Expert servo reverser that I had bought a long time ago to solve the problem with a simple disconnect/re-connect process. Guess not...

Thanks for the answers guys!
AV8TOR
http://www.ebay.com/itm/Turnigy-Serv...item27dc030db4
Old 12-29-2013, 06:27 PM
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Originally Posted by MetallicaJunkie View Post
Ok. But I am supposed to trust this made in China servo reverser over my new World Experts reverser because????

AV8T0R

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