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Mar 28, 2019, 01:00 AM
Registered User
I've got a brand new Horizon Hobby Parkzone T-28 and it went together easy and I have my Spektrum DX6 set up with it, with SAFE assigned to switch B to match my first plane. All the control surfaces seemed to be trimmed correctly with flat aileron and elevator with SAFE switched off. The problem is when I switch SAFE on, the ailerons move to a slight left bank and up elevator. When I turn SAFE back off, the surfaces return to neutral. I've swapped the servo leads and it still commands a left bank.

My question is - is that how it is supposed to be? I don't think so and I'm trying to think what might be wrong. Could the receiver be installed from the factory in such a way that it is not level or might there be something wrong with it? I don't expect to use SAFE much, but I'm afraid to make the first flight even with it switched off.

I've searched for others having this issue but haven't found anything else like it. Which probably means it is a common issue that I just couldn't find.

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Mar 28, 2019, 10:00 AM
Registered User
I may be totally wrong here, but I think I read in my dx6 manual that you can set the controls there and save the settings
Mar 28, 2019, 12:18 PM
Tony K's Avatar
You bought a great plane tgold, not sure about safe system, none of my planes have it. I would hold the plane up and move it around a bit to see if the control surfaces respond to angle while you have safe on. It is possible it is not responding correctly to flat and level.
Mar 28, 2019, 01:00 PM
geek from Cow Pie AZ
That may be failsafe default, try running up the throttle couple of seconds and then follow advice above from Tony K above.
Mar 28, 2019, 08:44 PM
Registered User
Thanks guys, but I think I still have a problem. I've downloaded the spm from Spektrum to make sure I have the transmitter programmed correctly. And I rebound the plane to this new model. I still get what I think is incorrect behaviour.

Here is what I'm seeing.

SAFE OFF - The ailerons are neutral as is the elevator. I pick up the model and move it around and I see slight control surface movements. That is I'm pretty sure the AS3X at work. The surfaces return to neutral regardless of how I hold the plane.

SAFE ON - With the model sitting on a level surface, when I turn on SAFE, the left aileron moves up about 5mm and the right moves down about 5mm. The elevator moves up a few degrees. When I move the model and put the left wing down, the left aileron drops (and stays dropped) until I return the model to level. Or at least that is how it is supposed to work I believe. In fact, the Ailerons return to neutral when I still have the plane in a slight left bank attitude. So I see SAFE at work trying to level the plane, but it's not actually bringing it to level, it's putting it into a left climbing turn. I did run the throttle up too.

I believe that if I turn SAFE ON and I take off, the plane will climb and bank left with sticks neutral. I believe if I turn SAFE OFF and I take off, the plane will accelerate with wings level on the ground until I pull back on the elevator stick. That doesn't seem right to me.

I could just turn SAFE off and not worry about it, but it doesn't seem right and I'm afraid the receiver is not installed level or is defective.

Zerts, the failsafe was a good idea, but I tested that and when I turned off the transmitter, the engine cut off as expected and the ailerons went to a hard left bank. Much more than what I'm seeing by turning SAFE on.

I suppose my next step is to go to Horizon support. It's going to be really windy here for the next week so I'm not going to be able to fly for a bit anyway. Thanks for the help and let me know if you have any other ideas are things to try.
Mar 29, 2019, 07:21 AM
Way to much free time!
CorvetteC5's Avatar
You called it!

It does sound like your SAFE RX is not mounted level and square to the wing and fuselage for its internal calibration. Easy enough to reposition it for the expected 'straight and level' behavior. Or trim out these offsets (at the TX or mechanically) but the control surfaces will likely still behave differently between SAFE on and off, unfortunately.
Last edited by CorvetteC5; Mar 29, 2019 at 07:30 AM.
Mar 29, 2019, 01:58 PM
Perpetual Noob
BoxCar31's Avatar
Are you certain your trim switches are set to ZERO? Trimming on ANY SAFE equipped plane must be done in the Experienced mode only. If you try to trim in one of the limited modes the receiver treats the trim adjustment as a stick movement and not a trim adjustment. Your description reads like the plane was in SAFE mode and an attempt was made to apply trim to get the plane flying straight and level.
Mar 29, 2019, 03:59 PM
Registered User
Thanks CorvetteC5 and BoxCar31 - I'll check out both today while I wait for the wind and rains to stop here. I'll have to figure out where I can get a 1-inch long level too. :-) I'll post back when I figure this out in case anyone else has the same problem.
Mar 31, 2019, 01:09 AM
Registered User
Got some cowl work done today on mine.
May 19, 2019, 07:58 AM
Registered User
trhodes1's Avatar
Originally Posted by ds8615
Got some cowl work done today on mine.
Just saw your photos - nice work. Would like see more of her.
May 19, 2019, 10:15 AM
Tony K's Avatar
Nice indeed, what size 3 blade you got on there? Stock otherwise?
May 20, 2019, 04:01 PM
Old newb

Make sure you start with a fresh model memory so every thing is zero.

The flat pad in the cabin will be level, if stock landing gear is installed.

I found the AS3X spm for the T-28 particularly brain dead so I rolled my own.

I forget but one mode only deflected the rudder a few degrees.

Since I lost my drive I do not have the program any more handy.

I recall I set 3 flight models.

Stabilize off (SAFE OFF of course,)
SAFE OFF (stabilize on with only AS3X)

I have not been playing much lately so I am going by (feeble) memory only.....
May 21, 2019, 10:36 PM
OR65 Eagles Nest
OK so I have a couple questions ...
I was just given a bunch of aircraft by a friend who I downsizing and moving he is keeping his kits but not his big planes I got a handful of these T28's I believe I have figured out I have 2 different ones or versions a smaller one with ailerons only and fixed gear and a larger one that has flaps and retractable gear possibly a e-flight version from what I have found so far I have only one of the larger version ...
I have gone thru the parts I got and seem to have 2 maybe 3 decent fuses one good wing and should have enough parts to build up a complete of the smaller what I believe is the parkzone version aileron and fixed gear only . how do I go about straightening the rudder and stab as they are bent /curved . I plan on building the smaller one up to give to a friend for his young son who was just beside himself when he got to come out to our season opener funfly this year his boy is 5 years old I gave him a mini vapor from my collection last month he was stoked now I want to get this completed so he can continue to teach and learn with his son
May 22, 2019, 11:09 AM
Landing is not optional
JamesonC's Avatar
Sounds like you have these two:

As for straightening the rudder, some pictures may help but the horizontal stab is a cheap replacement part that I wouldn't fool with trying to straighten. If it's the vertical stab, try hot water/steam.
May 22, 2019, 09:30 PM
OR65 Eagles Nest
yes that is the two different varients that I have only one of the EFL8350 versions
I have 3 halfway decent fuses just warped vertical stab and rudder for the other version PKS8250 without a RX in them I have 1 good main wing and several horizontal stabs NIP a couple canopies and cowls one good set of landing gear and a motor and esc likely a good full set of servos but have not yet had a chance to check out ... the rudder is torn loose on all 3 of the fuses so after I get them straight I plan on installing ca hinges for the rudder anyway ...
want to make this plane be a decent flyer so I can help get my friend and his young son flying
hid boy is 5 years old ... my friend told me that his son actually got taxiing down last night and did a couple short hops with the vapor I gave them he is was excited ...

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