Cessna flap relay

As the voice of inexperience here, I definitely admit that I must have obviously gotten the order of things fouled up...it seemed simpler and more cost effective to me to check connections and relay first...considering that the price of new motors, at least that I found, was around $600. I was trying to check the simplest, cheapest and easiest parts first before really taking things apart. I have learned several lessons throughout this airplane ownership experience already and i'm sure this will not be the last. But, considering that when I tested it, over and over and over again, it worked fine, it seemed to me that it was something between the switch and motor, not the motor itself. Wrong? Quite possibly.

Jim, I agree that there has to be a reason for the fry in the first place. But, it is an electrical component, and old one at that. Is it not reasonable to believe that age along with bad/ dirty connections could have been the cause of the fry?

Dont get me wrong, I'm not trying to argue with the experience and knowledge that you all obviously possess in a far superior form than I. I'm merely explaining where my thought process came from.

I still, however, fail to understand how it can be the motor itself when it works great most of the time and is not otherwise symptomatic. Would there not be other symptoms with it? Sluggish or "jerky" operation, high or low current draw maybe, otherwise irratic operation?

I'm definitely no expert when it comes to electric motors. I've never disassembled or otherwise tested, rebuilt or cleaned one. So I do not know what is inside an electric motor or really how it works. I will find out though. So, otherwise the only way I know to see if it is working is to try it and see if it is working. In this case, minus the obvious problem, it works great.

So, should I keep troubleshooting between the switch and motor in your opinion? Or go straight to the motor with my A&P? Again, All thoughts and comments are appreciated!!!


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I went back a re-read your posts and it sounds like the question has already been answered. Based upon Henning and Jim's posts, it sounds like I need to pull the motor, clean and service and try again. I see where you all are coming from with the "shotgunning" and I agree. Again, call it the voice/actions of inexperience. It just boggles my mind that it works flawlessly through 20+ full "cycles" of the flaps, then stops again. Acts like something other than the motor itself. At least in my mind. So, if the motor is the place to go, that is where I will go.


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Also....if your A&P considers this as a minor repair and your aircraft is considered a "Vintage" aircraft...one that is Type Certificated prior to January 1980.....you may legally use parts manufactured under a commonly known US standard....such as SAE, ANSI, MIL...etc

The most important aspect to consider when substituting parts is whether the failure of the part would prevent continued safe flight and landing. Often, there is a safety benefit when original parts are replaced. However, if the failure of the part would prevent continued safe flight and landing, then more data is required for approval. Industry standards such as Society of Automotive Engineers (SAE), American Society for Testing and Materials (ASTM), and National Aerospace Standards (NAS) are valuable resources to help provide data to justify approval. Appropriately authorized DERs have the necessary knowledge, skill, experience, interest, and impartial judgment to merit the responsibility for making these determinations and making findings of compliance with the applicable airworthiness regulations.
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http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_23-27.pdf
 
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weirdjim said:
What the hell is a "dead spot in the motor"??? Motors don't have dead spots. Motors have rotors. Motors have stators. Motors have brushes. Motors have a lot of things, but "dead spots" aren't on the list.

Please go play in some other sandbox.
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Wow...
 
weirdjim said:
What the hell is a "dead spot in the motor"??? Motors don't have dead spots. Motors have rotors. Motors have stators. Motors have brushes. Motors have a lot of things, but "dead spots" aren't on the list.

Please go play in some other sandbox.

Thanks,

Jim
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A bad or open winding/failed commutator will cause a 'dead spot' in a motor. A lot of the times when I see issues like this it's an arced up commutator that is the issue.
 
DC motors can have "dead spots". If the rotor winding associated with one set of commutator bars is open and the motor stops with the brushes on that spot, it isn't going to run until something happens to go get it off of that spot. If it isn't on that spot, it will run and momentum can carry it through the dead spot. Windings can chafe through due to relative motion between the winding and the core caused by the magnetic forces that make the motor rotate. It may be unlikely in that small of a motor but that doesn't mean that motors don't have dead spots.
 
Graueradler said:
DC motors can have "dead spots". If the rotor winding associated with one set of commutator bars is open and the motor stops with the brushes on that spot, it isn't going to run until something happens to go get it off of that spot. If it isn't on that spot, it will run and momentum can carry it through the dead spot. Windings can chafe through due to relative motion between the winding and the core caused by the magnetic forces that make the motor rotate. It may be unlikely in that small of a motor but that doesn't mean that motors don't have dead spots.
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Yep, even a build up of arcing points on the commutator can hold the brush from making contact and cause it without a failed winding.
 
Graueradler said:
DC motors can have "dead spots". If the rotor winding associated with one set of commutator bars is open and the motor stops with the brushes on that spot, it isn't going to run until something happens to go get it off of that spot. If it isn't on that spot, it will run and momentum can carry it through the dead spot. Windings can chafe through due to relative motion between the winding and the core caused by the magnetic forces that make the motor rotate. It may be unlikely in that small of a motor but that doesn't mean that motors don't have dead spots.
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also....if a brush hangs up and loses contact with the commutator...a bar can raise or burn due to the increased arcing.....causing a "dead spot".
 
SPAJC said:
So, should I keep troubleshooting between the switch and motor in your opinion? Or go straight to the motor with my A&P? Again, All thoughts and comments are appreciated!!!


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The motor isn't all that difficult to remove. Now, I'd NEVER do this myself, but I've got this friend Ernie that takes his airplane stuff down to the local auto electric shop and tells them it is from his airboat. Tells them to test and repair as necessary, and while it is out, no problem to clean it up, replace cheap parts (brushes, bearings) and reinstall. Ask if they found any problems that would cause intermittent operation. If not, back to the drawing board. It should cost less than $100 or so for a pretty complete rebuild (DON'T call it an overhaul).

Logbook entry? Can't do it because it was from an unapproved shop, but then again, who is to say that Ernie ever took it out?

Jim
 
weirdjim said:
The motor isn't all that difficult to remove. Now, I'd NEVER do this myself, but I've got this friend Ernie that takes his airplane stuff down to the local auto electric shop and tells them it is from his airboat. Tells them to test and repair as necessary, and while it is out, no problem to clean it up, replace cheap parts (brushes, bearings) and reinstall. Ask if they found any problems that would cause intermittent operation. If not, back to the drawing board. It should cost less than $100 or so for a pretty complete rebuild (DON'T call it an overhaul).

Logbook entry? Can't do it because it was from an unapproved shop, but then again, who is to say that Ernie ever took it out?

Jim
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Nope, can be logged as owner provided part, no worries. An A&P or a CRS can't send it to him, but the owner can.
 
Henning said:
Nope, can be logged as owner provided part, no worries. An A&P or a CRS can't send it to him, but the owner can.
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I think that takes it one step afoul of the letter and spirit. Owner PRODUCED and owner REPAIRED are two separate and independent matters.

Jim
 
BTW....it's an "armature" and a "field". :rofl:


I learned how to say dat when I was an engineer for the company who made Lamb DC motors.....:D
 
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Everyone in the thread on the owner produced parts wagon is blowing so much smoke its not even funny.

All the owner has to do to "participate" is provide the part to be duplicated.

Depending on how critical the part is, it may require FAA approval.
 
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weirdjim said:
What the hell is a "dead spot in the motor"??? Motors don't have dead spots. Motors have rotors. Motors have stators. Motors have brushes. Motors have a lot of things, but "dead spots" aren't on the list.

Please go play in some other sandbox.

Thanks,

Jim
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Did you wash your hands and keyboard after the diarrhea episode?
 
weirdjim said:
I think that takes it one step afoul of the letter and spirit. Owner PRODUCED and owner REPAIRED are two separate and independent matters.

Jim
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One thing to understand, the FAA wrote this liberally. They are not idiots, they know these things take common industry components and techniques. The owner can fabricate the whole thing if they please, or any component required. They can also direct the fabrication or acquisition of parts and services. In the end, the owner provides the mechanic a useable part.
 
weirdjim said:
My opinion is that the jury is still out on this assertion. :yes:

Thanks,

Jim
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If it's not commercial aviation or affecting commercial aviation, the FAA is trying to distance themselves, they don't have the budget.
 
It will probably sound like i'm being a smart a**, but i'm definitley not.....the way that you all explained it this morning makes perfect sense. I should have asked that first. So, we'll get started on the motor as soon as possible. Thanks for all the info!!!! Appreciate the info on the regs also....learning a lot here...thanks again!!!!


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SPAJC said:
It will probably sound like i'm being a smart a**, but i'm definitley not.....the way that you all explained it this morning makes perfect sense. I should have asked that first. So, we'll get started on the motor as soon as possible. Thanks for all the info!!!! Appreciate the info on the regs also....learning a lot here...thanks again!!!!


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No worries, wasn't digging at you, just pointing out a lesson everyone needs to learn if they want to cost effectively participate in their maintenance. There is an order you proceed in when chasing a problem. You do all the service related items first (like making sure all those relay connections were good) and make note of any anomalous things you see about parts. Next you start testing components and finding which ones are failing. Once you find parts that fail testing, only then do you start buying parts.

In the aviation sector, the ammo for the parts gun is bloody expensive.
 
weirdjim said:
I think that takes it one step afoul of the letter and spirit. Owner PRODUCED and owner REPAIRED are two separate and independent matters.

Jim
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But then again, you are supplying the "machinist" with the parts (the old motor) and instructions as to what to do, so the flap motor gets the Cessna part label scraped off and the "owner produced part" label stenciled on. I guess that isn't TOO far of a reach.

Thanks,

Jim
 
weirdjim said:
But then again, you are supplying the "machinist" with the parts (the old motor) and instructions as to what to do, so the flap motor gets the Cessna part label scraped off and the "owner produced part" label stenciled on. I guess that isn't TOO far of a reach.

Thanks,

Jim
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Exactly, it's very broadly written when you read it, even the interpretations there are on it I've read are broad and liberal. As long as it's GA, the FAA isn't inclined to get involved.
 
Henning said:
Exactly, it's very broadly written when you read it, even the interpretations there are on it I've read are broad and liberal. As long as it's GA, the FAA isn't inclined to get involved.
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....until someone loses an eye.:goofy::rofl::goofy:
 
timwinters said:
Likely fueled by alcohol considering the time of the post.

At least I hope no one is that big of an ****ole when sober.
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Not likely. Didn't get home from work until 11:30 with 20 folks in the class with me until then. I'd have to have taken it intraveneously to be sloshed less than an hour later. Sleep deprived, probably. ****ed off at having to drive an hour home after work, probably. @$$#0!e on occasion, just like everybody else.

Jim
 
This all could sound like a motor commutator that needs to be undercut. A motor disassembly and commutator inspection can confirm that.

If so, find a motor repair shopman that knows how to refinish/machine the commutator and knows how to undercut the mica separators. Do not allow them to simply clean the commutator with emery paper! And do not just machine the commutator. Those slots between the commutator bars have to be cleaned out & undercut.
 
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The troubleshooting needs to be completed yet. This is where owner and even some mechanics fail miserably.

How long have you had the plane?

Did this start after someone serviced the flaps such as an annual inspection?

Do they get stuck at the same degrees of flap extension every time? (bolt catching on something)

Do they get suck on the ground or just in the air?

Can you make them fail by having helpers apply a load to both flaps and operating them?

Does the motor sound like it is grinding?

What does the wiring on the back of the switch look like? Tight/no burns?

Do you have fuses? Is the flaps on a dedicated fuse or is something else in the same circuit?

When the flaps as stuck does the other system on the circuit fail too (if applicable)?

Removed the fuse and looked for corrosion in the fuse holder contacts?

Does the wiring to the fuse holder look good?

There is probably a plug in the wing root allowing disconnecting all wing electrics from the fuselage is that plug and its contacts in good shape?

Did you solder the terminals onto the relay like the wiring drawing says?

Assuming its the motor your options look pretty limited as there was a service kit issued way back in the 1980's to get rid of those actuator/motor assemblies. Its a very invasive kit requiring modifying ribs and wiring to make the new ones fit. Tho it may be possible just to bolt a later motor on and make it work. Other option is getting an electrics shop to repair the motor you have. I doubt any aircraft accessory overhaulers support that motor. My first call would be these guys:

http://www.qaa.com/products/aircraft-motors/aircraft-flap-motors

If they won't do it they may know who will.

If it were my airplane, again assuming everything points to the motor i'd be looking at salvage option before disassembling the airplane. Get a salvaged part then dissect it. If its in decent shape put the motor in.

Troubleshooting is like being a doctor, use the FORCE.
 
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And we need to know not only the HOW but the WHY.

bnt83 said:
The troubleshooting needs to be completed yet. This is where owner and even some mechanics fail miserably.

How long have you had the plane?

I'm not sure this is germane to the process. What difference does length of ownership mean in the scheme of troubleshooting

Did this start after someone serviced the flaps such as an annual inspection?

Excellent question. More troubles come from inspection/other repairs than anything else.

Do they get stuck at the same degrees of flap extension every time? (bolt catching on something)

I think the OP says that they only get stuck in the UP position, not down or anywhere in between.

Do they get suck on the ground or just in the air?

I think the OP said that he did the up-down test extensively on the ground but that they stuck UP in the air.

Can you make them fail by having helpers apply a load to both flaps and operating them?

Good idea.

Does the motor sound like it is grinding?

I don't know how you would hear this while in flight. Too much other noise going on.

What does the wiring on the back of the switch look like? Tight/no burns?

Don't understand the necessity for this question.

Do you have fuses? Is the flaps on a dedicated fuse or is something else in the same circuit?

There was no indication of a fuse blowing. No mention of fuse replacement.

When the flaps as stuck does the other system on the circuit fail too (if applicable)?

n/a

Removed the fuse and looked for corrosion in the fuse holder contacts?

Longshot

Does the wiring to the fuse holder look good?

Longshot

There is probably a plug in the wing root allowing disconnecting all wing electrics from the fuselage is that plug and its contacts in good shape?

Not in a 150 so far as I know.

Did you solder the terminals onto the relay like the wiring drawing says?

I tend to trust crimped connections to terminals as soldered connections tend to break right where the solder stops and the bare wire continues. Sort of a built-in fracture point.

Assuming its the motor your options look pretty limited as there was a service kit issued way back in the 1980's to get rid of those actuator/motor assemblies. Its a very invasive kit requiring modifying ribs and wiring to make the new ones fit. Tho it may be possible just to bolt a later motor on and make it work. Other option is getting an electrics shop to repair the motor you have. I doubt any aircraft accessory overhaulers support that motor. My first call would be these guys:

http://www.qaa.com/products/aircraft-motors/aircraft-flap-motors

If they won't do it they may know who will.

Any self-respecting auto electric facility worth its salt can repair that motor, even if it means using windshield wiper motor parts from a '56 Buick. Just like the horn relay from a Pontiac.

If it were my airplane, again assuming everything points to the motor i'd be looking at salvage option before disassembling the airplane. Get a salvaged part then dissect it. If its in decent shape put the motor in.

Don't even THINK about that Cessna mod. That must have been a design given to a first-year engineering student intern from Wichita State.

Troubleshooting is like being a doctor, use the FORCE.
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And if the FORCE doesn't work, sometimes a larger hammer will :yes:

Jim
 
weirdjim said:
And we need to know not only the HOW but the WHY.



And if the FORCE doesn't work, sometimes a larger hammer will :yes:

Jim
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I'm not surprised you felt compelled to grade that like a term paper but perhaps the guy with the funky flaps could start answering some questions.


All of your "longshot" comments are ridiculous. If it takes 15 seconds to verify the fuse holder isn't all corroded up why wouldn't you do it? Because you know better right? (Dead spots in a motor)

I've see a fuse holder replaces 5 times doing a logbook research once.

The relay uses crimped contacts and a flag on the drawing says to solder the contacts to the relay.

Where did I say peruse the service kit?
 
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bnt83 said:
I'm not surprised you felt compelled to grade that like a term paper but perhaps the guy with the funky flaps could start answering some questions.
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I didn't GRADE it, but gave the OP some additional information that might help him. If I had to grade it, I'd give it an A, maybe knock off a few points for an A- for not telling him to take the motor to a local fixit shop if that's what it looks like for the fault. Nice job.

Jim
 
weirdjim said:
I didn't GRADE it, but gave the OP some additional information that might help him. If I had to grade it, I'd give it an A, maybe knock off a few points for an A- for not telling him to take the motor to a local fixit shop if that's what it looks like for the fault. Nice job.

Jim
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You offered very little additional information/ideas. :rolleyes2:

Pulling the motor means hangar queen. Ebay salvage of the same part number means something to work on without sacking the airplane.
 
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Its a good thing Jim is a stubborn old koot because a young guy would have run the other way by now.
 
If you can make it fail on the ground after verifying there is no bolts, bend rods or binding, what about unhooking the motor wires and hooking 12 volts directly to the motor to bypass the wiring in the plane?

If it still fails doing that check, its obviously the motor.
 
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