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TM4197
06-17-2010, 01:31 AM
I placed this on WW1 Planes because I know you guys use the same equipment basically. I have a SIG Bristol Scout all stock, no mods..and started to have some strange things happen in flight. I probably have 20 hours on the plane and gear. Last night, I went to full power at straight and level flight ( I rarely do that) and when at full power I had no right rudder...I saw a slight twitch but not enough to turn. I tried turning left...no issues at all. Throttled back, and turned right again, this time full rudder. Advance the throttle to 3/4....turned right....no rudder. Back again to 1/2 throttle...full rudder. I can also duplicate this on the gound. You can see the servo trying to move...but its very small. Come down to 1/2 power and she moves perfect. I have a GWS 10a ESC, 2 HS micro servos and a Corona 4 channel rec. (which all my WW1 planes have) and no issues like this. I know one of you machine gun racken guys has had this happen in battle. Any advice? any ideas? I have not begun to swap out any gear yet, because the rest of my planes are 100 miles away. [popcorn]

Wildflyer
06-17-2010, 01:48 AM
When you duplicate this on the ground, try holding full right rudder, and then advancing throttle, I would try it with the ESC both working and unplugged ( you may have to use a separate rec battery )

You don't mention the trans you are using, is it at all possible there is a mix turned on that cuts out right rudder at something over 1/2 throttle.

Unless something weird is wrong with your equipment, the servo signals must come from the TX, but in the wonderful world of electronics, strange things can happen, too bad the rest of your stuff is 100 miles away, swapping parts may be the way to pin this down.
Good luck

dbcisco
06-17-2010, 02:43 AM
What TX are you using?
I had a similar thing happen when I let my students use my Futaba to test the planes they made in Reflex. (I use RMK to teach 3D modelling).They decided to "fix" the settings on the TX instead of their models.

Larry3215
06-17-2010, 02:53 AM
Could just be a bad servo that cant handle the extra load when the plane is going at speed or has the extra prop blast over the rudder.

First remove the prop for these tests.

Try holding on to the rudder with your fingers and move the stick right and left with the throttle OFF.

See if the servo has the same strength each way. Check if it has the same strength for all of its travel too. If the pot is bad it may move ok for the first part of the travel but get "stuck" part way over.

Check to be sure no linkages or rods or what ever are bending or doing odd things when under pressure.

Next, throttle up and repeat the tests. Dont run the motor at speed for long or you will over heat it. You may want to unplug two of the motor wires from the esc for this test.

If it only acts wierd when the motor is throttled up - look for that odd mix or maybe the bec voltage is dropping or something like that.

TM4197
06-17-2010, 02:54 AM
I use E-Sky FM tx. They have been very strong, no issues (YET) and no programming.

WIldflyer: Rudder was held to the right, throttle applied. I released the rudder and tried to input right again...no luck.

TM4197
06-17-2010, 03:00 AM
Larrry, thanks for the ideas. Pull is same when I held the rudder. I unhooked the push rods, went through the motions...still no rudder at above 1/2 throttle. I changed servos from Elv to Rudder, still get the same thing.....So, it must be the transmitter??

dbcisco
06-17-2010, 03:07 AM
[QUOTE=TM4197;727987]I use E-Sky FM tx. They have been very strong, no issues (YET) and no programming.

They are pretty hardy. Hard to mess one up.

TM4197
06-17-2010, 03:10 AM
Well, everything goes bad sooner or later. They have been good radios. Well, I guess I can just use this one and fly NASCAR circuits :D

dbcisco
06-17-2010, 03:26 AM
Could it be the rudder channel on the RX?
Anyone nearby with a TX to test it?
If you're close to Philly let me know.

TM4197
06-17-2010, 03:31 AM
Iam thinking it is that problem..yes

My gear is at my other home in Delaware, I am in Virginia right now, why I didnt bring my flight box is beyond me. I got one battery left with me, so thats about 14 mins of left turns...what the heck! At least its flying!

Larry3215
06-17-2010, 03:46 AM
You can plug the rudder into the elevator channel and plug the elevator into the rudder chanel and do the tests again.

That should narrow it down to the tx or rx.

If the problem follows the moved connection, its something in the tx. If it stays on the same rx channel - its the rx.

TM4197
06-17-2010, 03:49 AM
Looks like its the transmitter!

TM4197
06-17-2010, 04:14 AM
Thanks for all the inputs. Looks like its the transmitter. Something for me to take apart now and look at. Have great flights everyone!!

degreen60
06-17-2010, 04:43 AM
You can plug the rudder into the elevator channel and plug the elevator into the rudder chanel and do the tests again.

That should narrow it down to the tx or rx.

If the problem follows the moved connection, its something in the tx. If it stays on the same rx channel - its the rx.

This only test the servo. The rudder is now controled my the elevator stick and the elevator servo is now contorled by the rudder stick. The TX still sends out the same channel stream and the receiver still decodes the stream the same. If the problem stays with the rudder, suppect the servo, if problem moves to the elevator you know it is not the servo. It seems the problem shows up when throtle channel goes to long pulse, if throtle is channel 3 and rudder is channel 4 I would suppect something is making throtle pulse too long and causing sync to be lost at the receiver. I am guessing the TX is PPM, if the TX is PCM then it is a whole differant thing.

dbcisco
06-17-2010, 04:50 AM
You can plug the rudder into the elevator channel and plug the elevator into the rudder chanel and do the tests again.

That should narrow it down to the tx or rx.

If the problem follows the moved connection, its something in the tx. If it stays on the same rx channel - its the rx.

That won't work. Only if you can change channel assignments on the TX can you issolate TX vs RX. Can't do that on the Esky.
My bet is on the RX bad.

TM4197
06-17-2010, 04:50 AM
I found my old 4 channel and just got it charged up. Just enough to test it. The rudder works fine with full throttle. No other issues. Went back to the E-Sky and no rudder at full throttle.

dbcisco
06-17-2010, 04:51 AM
I lost the bet.

TM4197
06-17-2010, 04:58 AM
Hey...thats not so bad...I got it figured out with you guys!! How do you get 3 years of dust off an old futaba radio...damn thing actually charged up..unreal! Now, I just need a big ole fat Philly Cheeze Steak~~~:D

dbcisco
06-17-2010, 05:03 AM
Hey...thats not so bad...I got it figured out with you guys!! How do you get 3 years of dust off an old futaba radio...damn thing actually charged up..unreal! Now, I just need a big ole fat Philly Cheeze Steak~~~:D
I can get you that, but it will be cold or gone by the time I get to you.:D

TM4197
06-17-2010, 05:05 AM
Might have to bring some planes up that way cross the Delaware and do some flying with ya~ and damn sure gotta have a cheeze steak...the best in the world is in Philly!

Larry3215
06-17-2010, 09:57 AM
This only test the servo. The rudder is now controled my the elevator stick and the elevator servo is now contorled by the rudder stick. The TX still sends out the same channel stream and the receiver still decodes the stream the same. If the problem stays with the rudder, suppect the servo, if problem moves to the elevator you know it is not the servo. It seems the problem shows up when throtle channel goes to long pulse, if throtle is channel 3 and rudder is channel 4 I would suppect something is making throtle pulse too long and causing sync to be lost at the receiver. I am guessing the TX is PPM, if the TX is PCM then it is a whole differant thing.

He already tested/swapped the servo and it works fine.

But you and db are correct - it wont isolate tx from rx.

My bad!

degreen60
06-17-2010, 01:02 PM
I found my old 4 channel and just got it charged up. Just enough to test it. The rudder works fine with full throttle. No other issues. Went back to the E-Sky and no rudder at full throttle.
Now the question is what is wrong with the transmitter. My first guess, sense it only fails at full throtle the throtle pot has got dirty on one end and the slide is not making good contact at full throtle. Course guessing is not a good way to trouble shoot. If you have a scope and can look at the encoder pulse train then you will probably see the failure and can trace it back to the problem. If the transmitter is worth the cost of shipping I would be glad to see if I can find the problem for you and fix it. Course cost to ship both ways will probably cost over $20.

TM4197
06-17-2010, 02:29 PM
Should be interesting to find out. I got some geewizz guys at my office that have all the latest and greatest gadgets, they actually scare me sometimes. I will give it to them and let them play with it. It might come back looking like a refridgerator, but will work. Mean while, I have an antique Futaba that refuses to die I can use until this weekend, then back to Delaware.

7car7
06-17-2010, 06:23 PM
If I read your above comment correctly, you said that if you give it full right rudder, it goes full right rudder? THEN if you add throttle while at full right then the right rudder goes away?

If that's the case, it sure seems like a voltage drop at the plane to me. Perhaps a new ESC would be where I'd be looking.

We did rule out a flexing push rod due to prop wash/ air speed, correct?

TM4197
06-17-2010, 10:43 PM
7Car7

I was finally able to hook another transmitter up. I can not duplicate the problem. If I go back to the E-Sky, I get the failure again above 1/2 throt. No issues at all with the old futaba. The battery dosnt last long on the Tx anymore, but then again....shes been around a long time. With the E-Sky, I can fly all day below 1/2 throttle. Its just nice to have the power when ya need it. I have some friends yanking the Esky apart as we speak. We;ll see whats up.