apprentice flight problems - RC Groups
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Sep 13, 2012, 10:07 PM
The wind caused that!!
hoghead5150's Avatar

apprentice flight problems

ok, i'm new and had some horrible problems today. see if ya'll can help me out!

eflite apprentice, fully stock, never crashed, always flown great.

today i took her out, and upon takeoff she didn't want to climb. we are talking full throttle, after about 3/4 of up elevator she finally climbed, but as soon as i relaxed the elevator stick she nosedived!!! i pulled her back up and this became the norm. finally got enough altitude to try some trim. FULL up trim and it would fly level (at full throttle) for maybe 20 seconds then start to climb. now it would climb constantly, and it would take at least 3/4 DOWN elevator to get her to come back level. mess with trim some more. got trim back centered and it would fly level for about another 20 seconds then start nosediving like it did on takeoff.

brought her around and landed. not pretty but on the wheels. checked everything i could think of. all flight surfaces are square and level with trim set to center, nothing loose. CoG is spot on at 3 1/4 per the manual. battery secured, nothing binding that i could find.

second flight, same as first!!!!

the ONLY thing i have been able to find that might be wrong is the elevator servo. when i move the elevator stick, the servo seems to move inside the foam. the horn is not stripped, and it gives movement to the elevator itself, but the servo is surely moving forward/backward as it cycles.

could this little movement of the servo be enough to cause such a terrible flight problem??
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Sep 13, 2012, 10:37 PM
Yes, it probably is the loose servo. Even if it isn't it needs fixed or it will be the problem.
Sep 13, 2012, 10:44 PM
The wind caused that!!
hoghead5150's Avatar
the only other thing that changed from the last flight to this one is my transmitter batteries (rechargeable enegizers) were low, so i swapped in some dollar store batteries. they showed fully charged on the transmitter (dam led's on the dx5e), but maybe they were not contacting good, or something. it felt like i had control the entire time, not dead feeling like i had lost contact, but i was fighting pretty hard just to keep her in the air.
Sep 13, 2012, 11:16 PM
Registered User
Re-secure that and check again on the ground first! Be sure you are getting good movement of the control surfaces. It is not doing any good trying to move something when it (servo) is not stable.
Sep 13, 2012, 11:17 PM
Registered User
How was the charge on the battery?
Sep 13, 2012, 11:24 PM
The wind caused that!!
hoghead5150's Avatar
charge on the planes battery was full. just off the charger.

with battery plugged in, plane on ground i could hold the elevator, cycle the stick and watch the servo slide front/back. it would try to move the elevator and if i held slight pressure on it the servo would still slide. no pressure on the elevator and the servo would shift a tiny bit (you could see it move a hair). i am getting full throw on the ground if i don't hold the elevator with my hand!!
Sep 14, 2012, 12:43 AM
Registered User
Sounds like you need to pull that servo out and secure it in place again. It needs to be stationary. If you disconnect the control rod from the servo arm, re-attach the arm and just hold the servo in place, do you still get good movement from it?
Sep 14, 2012, 03:58 AM
Registered User
xmech2k's Avatar
I already replied on your WF post.

And make sure all the tail feathers are tight. It's been a while, but isn't it 2 screws that hold them on? Make sure they're not bottomed out before they held everything tight.
Sep 14, 2012, 07:15 AM
Registered User
The loose servo sounds likely, but one thing I haven't seen mentioned yet. How about your rubber bands that hold the wing. If they are fatigued and stretched, they will let the wing move up and down and change the angle at random. This could cause this also I would think.
Sep 14, 2012, 12:49 PM
Registered User
Check to make sure that your battery and connections are good and that the battery is not shorting. Last week while I was flying my new Tower Hobbies Corsair, I found that the plane would suddenly lose all elevator and aileron movement as well as loosing power, I knew that the battery was fully charged. After I got it down, I heard the servos chattering a bit. What I found was that the battery leads were shorting and any movement in a certain direction would cause the battery to short. I was able to land her safely, but never discount that the battery may actually be at fault and it may not be the servos.
Sep 14, 2012, 01:55 PM
Redacted per NSA "suggestion"
dedStik's Avatar
Glue in that servo. My PZ BF 109 dislodged the elevator servo from a hard knock landing once, caused issues until I fixed it. It's really unsafe to fly if the servo is moving on input.
Sep 14, 2012, 03:16 PM
The wind caused that!!
hoghead5150's Avatar
got servo reglued. used a shim to get the servo as tight into its pocket as i could, then shoe goo'd it in place. it doesn't move at all now.
planes battery just came off charger. (it was fully charged before, just making sure it is topped off)
transmitter batteries are on the charger. (enegizer rechargeables, they were low on the last flights where i had problems and i swapped in some dollar store batteries)
rechecked CoG. battery installed, everything ready to fly. CoG is exactly 3 1/4 inches from leading edge of wing (spot on according to manual)
checked ALL servo's for binding, looseness,
checked ALL flight control surfaces. all are dead level at rest with trims on radio centered.
even pulled cowl off and checked motor, motor wires, motor mount screws, and firewall. all good.

it seems like everything is checking out good, did a power test (no meters i'm still new). on ground full throttle, while at full throttle, moved all flight control surfaces with radio to maybe check for problems under load. not sure if this actually works, but it made me feel better!

i did notice that with the plane on the ground, me standing over plane with stab against my calves doing the engine run that the tail feathers sure seem to move around alot from the wind off the prop. the tail feathers are tight, the screws are all the way in and tight, but the feathers sure seem to bounce around from the turbulence.

is there anything else i could check, should check, i'm a little nervous about putting the bird back up in the air!! i did it twice yesterday (when all these problems happened), and i was able to get her back to the ground safely, but a few times i thought i was gonna lose it.

oh yeah, checked battery wires- they good, checked esc to battery wires- good, checked esc to receiver wires and plug-good, checked well, every wire on the plane. all good, no bad connections, no nicks, scrapes.
Last edited by hoghead5150; Sep 14, 2012 at 03:43 PM. Reason: addition
Sep 14, 2012, 04:25 PM
Arizona Fun

Loose servo!

I had a foam airplane elevator servo come loose once. Before a flight I noticed the elevator seemed mushy and without full travel so I took the wing off saw it was loose. If your servo was loose, it likely caused your problem and you should be fine now. I have an Apprentice, she's a beauty : Relax and enjoy your next flight
Sep 14, 2012, 07:30 PM
Registered User
check and make sure the clevis are all secured with their clear rubber band and that they are not broken.
Sep 14, 2012, 09:09 PM
The wind caused that!!
hoghead5150's Avatar
well here is the update: mixed emotions...

was a little wind today, so this added to my nerves. solid 8 mph according to our wind meter.

first flight,,,, perfect! handled the wind fine, flew just like it always did. i was nervous so some of the jumpness of the plane was all on me.

second flight,,,, same as first. only difference was the wind picked up a little to 9.5mph. plane flew great, handled the wind fine and my nerves were a little better.

third flight,,,, uh oh. started fine, then about a minute into the flight the plane started nose diving again!!! here is the weird part. the wind had died down. wind was around 3mph on the meter. now going WITH the wind, at half throttle the plane would fly perfectly level, give it the throttle and the plane would climb. not straight up, but up at a pretty decent angle.

turn around and fly INTO the wind, and at half throttle the plane would pitch down at around a 40* angle!!! at full throttle INTO the wind, the plane would nosedive BAD!!

landing this time was a HUGE pain in the butt, but i got her down. checked everything again. CoG is spot on, all control surfaces are perfectly in line, battery shows 3.7v per cell (fixing to throw it on the charger and see how many MaH it takes). servo i reglued was good and solid, all control rods are free and not sticking, servo horn not stripped.

why would it climb going WITH the wind, and dive going INTO the wind? this is exactly opposite of how it used to react..

remember, this plane is bone stock, NEVER crashed, no rough landings. nothing is bent, broke, or distorted! (well i did add different wheels. has a 3 inch dubro micro wheel on the front, 2.5 dubro micros on the mains.
Last edited by hoghead5150; Sep 14, 2012 at 09:10 PM. Reason: addition

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