MinotRich

I have a Slowpoke 40 that has an aileron servo that won't center correctly. This plane has separate servos for each aileron, and I have replaced the servo a couple of times thinking it had a bad potentiometer. It seems to work fine for a few flights after I replaced it, but the problem keeps recurring. Each servo has a 6 inch extension and is connected through a y harness. Could the length of the extensions and the y harness be the cause of my problem? The aileron finally centers after "fluttering" past center about 3 times. I don't notice any adverse affects in flight, but it just bothers me and I don't want to wind up crashing the plane by just "letting the problem" go.
Anyone ever experience this and/or have a solution to my problem? Any and all advice would be greatly appreciated! Thanks, Rich

Rodney

A bad connector on the extensions could be your problem. many of the less expensive extensions are not very good and the contacts build up corrosion over time that can cause this problem. If it goes away after dissconnection and reconnecting the extensions, this is the most probable cause. Get rid of the extensions, solder up some longer leads that eliminate the need for extensions.

dirtybird

My Feedback: (5)

I am afraid I have to disagree with Rodney.
Soldering wires together for servo connections is a tricky job. You need a jig to hold the wires in the correct spot for the soldering operation and need to provide support for the wires past the end of the solder to ensure they dont break from vibration while in service.
Unless you have a lot of soldering experience there is a high probability of a bad or cold soldering joint.
I think the novice would be better off with good quality pre made connectors.
There has been some trouble with the lower quality connectors but usually it just results in a servo that hunts or will not respond. Then you just replace the extender.
A bad or cold solder joint can mean the loss of an aircraft.

JohnBuckner

My Feedback: (1)

I gotta concur with Rodney. No special tools are needed save a very cheap pencil iron and and a three dollar table top vice (vacumn, clamped or weighted). Soldering up your own special leads and custom Y's (I,ve done up to four ways) by far provides more reliablilty than the rats nest of a bunch of extentions and an excessive bunch of connectors that always result in an excessive wire run with the associated line losses.

It can be learned in just a few minites if the right procedure is used. I am certainly no electronics hobbiest or expert in any way however I will trust my custom leads that I have done for many years with never a failure traced to the soldered harness every time over a collection of excessive and unessesary plugs.


John

dirtybird

My Feedback: (5)

Well good for you.
NASA, however, does not agree with you as soldered connections are not allowed on equipment supplied under contract to them. It seems there is no way to inspect a soldered connection without sawing it apart. That tends to ruin its function.

3dd

My Feedback: (6)

well it seems nasa would do better on some other problems they have than worring about cold solder joints,but you are right to a point ,a cold joint is no good but a hot joint with shrink tubing is way better than a plug any day

JohnBuckner

My Feedback: (1)

Dirtybird I was offering a differing opinion and I am sorry you are uncomfortable with that. Concerning NASA I seriously doubt that you will ever see any plugs on a space craft with cheap crimped fittings that corrode easily like most of us commonly use for extensions. So my preference will always be to minimise the plug count, it does not take an engineer figure out the advantage in that.

John

MinotRich

I replaced the "Y" harness and extension wires tonight one by one and it turns out that I had a bad extension. Comparing it to a Futaba extension, I realized that it was a bad Hobbico extension that was the cause of the problem. Thats what I get for buying what the local hobby shop has in stock rather than wait to place an order through Tower Hobby.
I have a soldering iron and have thought about soldering up my own leads, but my soldering skills leave a lot to be desired. It seems I never have enough hands to hold everything in place or I can't ever get the soldering iron to heat up, the tip tinned, etc. Seems I always wind up with a "cold joint" which is usually worse than the mess I had in the first place and a helluva lot uglier too!
Didn't mean for this to cause a new discussion on the pro's and cons of soldering either. Lighten up a bit guys... this is a Hobby and it's supposed to be FUN, remember?

Rodney

Having worked in the aircraft and space craft field for many years in instrumention and testing, I can guarantee that there is a lot of soldered connection on spacecraft and aircraft. Tests we did many years ago show that a good crimp or weld is slightly better than a soldered connector but not by much. True, you have to pay attention to what you are doing but I believe I can teach anyone with normal inteligence to make a good solder joint on wire to wire in about 10 minutes that will be far better than most extension connections we use in RC. Reliability and long lasting equipment was the prime responsibility of the groups I either headed or worked in and we proved that good solder connections were very reliable.

dirtybird

My Feedback: (5)

Well Rodney I worked many years for aircraft and spacecraft manufacturers as well. You are correct a good solder joint is very reliable. However a bad solder joint is not.
The cheapest extender comes with a crimped connector that is put together with a tool that is calibrated. Its like using a torque wrench on a nut. Its too bad that some manufacturers choose to inferior material. As a consumer you have control over what you buy. Ypu should get only gold plated units. EMS sells them at a very reasonable price put together by an expert.
It is also true that good soldering skills can easily be learned. But most beginners to this hobby don't posses this skill and do not know where to go to learn it. You also need a good jig to hold the wires and heat sinks to prevent the solder from running down the wire. I bet not one of you has this available.
I spent about 10 years as a technician and 40 + years as a design engineer. I have the jigs and the skill. I still managed to wind up with a bad solder joint that nearly cost me an airplane on two occasions. You have to be very careful and sometimes you get in a hurry.
I still think the average modeler would be better off buying his connectors than soldering.