IS THERE ANY WAY TO TEST THE LANDING GEAR ELECTRONICS...... ON THE GROUND.????....... I HAD A FLIGHT THE OTHER DAY THAT MY H WAS UP AT 5' AGL AND FLIPPED GEAR SW UP AND LEFT GEAR STARTED TO MOVE THEN STOPPED AND RIGHT DID NOT MOVE AT ALL........
LANDING GEAR
- Thread starter Flying Egle
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CraigCam
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If you've never had a problem before then you should check your assemblies. The landing gear motors inside the housing can over time get stuck. They are sealed well so it's not a dirt problem but they can get sticky after hard landings or any forcing of the leg. I did a full upgrade firmware for a hobby shop friend who has the TH and his right gear was sticking. I did the hold the H upside down trick and that got them going. I still felt that one was still a little slow so I went ahead and removed them both and put the assemblies on the bench. And here is what I discovered.
Internally, the motor runs a simple screw jack that the leg attaches to via the socketed end attached to the screw jack. It's got two small brass washers inside on either end of the horizontal screw shaft to hold it centered in the housing so it rotates freely. They use a light grease inside there to help hold it all in place.
This design is not meant for hard hits at all as the brass washer can actually end up impeding smooth turning when it gets knocked around.
What I did was first just swap the left side with the right side to make sure it was not a faulty circuit. They both worked but the one that was suspect moved less efficiently. Once opened up, I found I was missing a washer in the suspect leg motor assembly. So this one the shaft would move inside the housing while turning and once it "feels" any resistance stops turning and becomes non responsive to switch flipping. As you discovered that's no good in flight.
Unfortunately, QC at whatever Chinese jobber made those leg assemblies seems to have been low. It's impossible for a new out of the box TH to be missing this critical washer.
So if you have never bounced it hard off the ground and always had normal landings then the landing gear motor should work when you flip it over and cycle. If it's got problems, the testing turned over helps determine what you should do next ( send to Yuneec or DIY) to resolve the problem.
If you do open up the housing to check that motor assembly make sure you don't loose one of those washers like I did and spend hours hunting for it[emoji1]
Internally, the motor runs a simple screw jack that the leg attaches to via the socketed end attached to the screw jack. It's got two small brass washers inside on either end of the horizontal screw shaft to hold it centered in the housing so it rotates freely. They use a light grease inside there to help hold it all in place.
This design is not meant for hard hits at all as the brass washer can actually end up impeding smooth turning when it gets knocked around.
What I did was first just swap the left side with the right side to make sure it was not a faulty circuit. They both worked but the one that was suspect moved less efficiently. Once opened up, I found I was missing a washer in the suspect leg motor assembly. So this one the shaft would move inside the housing while turning and once it "feels" any resistance stops turning and becomes non responsive to switch flipping. As you discovered that's no good in flight.
Unfortunately, QC at whatever Chinese jobber made those leg assemblies seems to have been low. It's impossible for a new out of the box TH to be missing this critical washer.
So if you have never bounced it hard off the ground and always had normal landings then the landing gear motor should work when you flip it over and cycle. If it's got problems, the testing turned over helps determine what you should do next ( send to Yuneec or DIY) to resolve the problem.
If you do open up the housing to check that motor assembly make sure you don't loose one of those washers like I did and spend hours hunting for it[emoji1]
Ok flipped over H and tested....... and flipped gear sw and again only 1 side about 2 inches and stopped....... tryed my second H and it did the same thing........ seems like a problem with ST16........ any ideas ?
You know I have the same thing with the first flight each day. When I had my first crash, I had to remove the gear to replace a prop arm, now I know the solution. I'm not going to fix it till winter as all I have to do is raise and lower once to make it work for the rest of the day.
Thanks for the post Craig.
I resolved the issue.... completely in-assembled gear and moved the screw mech to mid position on the one that started to move re-assembled the gear mech and turned on , the removed gear reinitialized to down position..... flipped H and cycled gear up and both worked fine....... did the same on my second H and all are working fine
My gear worked fine for 11 months. Then I had a minor hard land and only one leg would move an inch (even upside down). Removed the legs to check contacts and reverse legs and found the back side of the box housing contacts had moisture on both legs (they where wet). H stays indoors and I haven't been around any rain or water anywhere,don't know why they were wet. The landing gears worked fine since'(fingers crossed)..
I have bent the screw jack on a hard landing. I straightened it out, but not as precise as it should be. It would work but was a little jerky. I just replaced it with a new assembly that inserts into the H easy enough. I wish I could get that one part (screw jack) and replace it instead of buying the whole landing motor assembly. I think the screw jack (looks like a cork screw with a tee handle) is the weak link in the landing gear assembly.
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