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Jan 07, 2013, 06:16 AM
Happy safe flying :-)
richard1971's Avatar
Thread OP
Help!

FMS mini t-28 uncontollable


Hi,

I'm new to this thread and wondering if anyone could help.
I bought an fms t-28 mini (800mm) used stock batteries ar600 reciever pn dx6i and added a flaps using micro servos, assembled everything, checked controls, 45mm cg from the front edge sides of main wings- everything seems ok. Went to the field (6mph wind) and hand launch her, flown straight then bank left, straight again then some mini acro loop (100ft high), after that she seems to be uncontrollable, trying hard to gain the balance but its impossible, until I dropped her into the ground. Propeller gone and the motor mount slightly cracked which can be repaired by epoxy I think.
My skill level is a bigginer and would be able to fly my e-flite mig 15 and carbon cub...

Queries are:
- is my cg correct?
- bought a 2 blade prop, easy flyer, is it ok?
- is the stock battery underpowered
- any advice and help would be really great.

Thanks,
Richard
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Jan 07, 2013, 08:01 AM
Registered User
The following thread would be a good place to search, I have their 800mm p47 and it was extremely tail heavy so you might start with cg

https://www.rcgroups.com/forums/show...t=airfield+800
Jan 07, 2013, 10:32 AM
Registered User
I have 3 friends with these same planes..............none can get them to fly reliabley. Theirs tend to veer to the right when they take off from ground or hand launch. Unfortunately, these planes are really not "beginner" planes. But yes, start with the CG and then check the control surfaces for warping or other irregularities.
Jan 07, 2013, 11:41 AM
Happy safe flying :-)
richard1971's Avatar
Thread OP
Thank you mates for the very useful info. I've flown my e-flite umx mig15 with ease and it's fast & responsive. I thought this fms mini t-28 is better than the other fms warbird. Anyway need to check the cg again and change the propeller to 2 blade.
Jan 07, 2013, 03:53 PM
Redacted per NSA "suggestion"
dedStik's Avatar
I've got the 800mm version of the Zero, what sized battery are you flying? I'm using a 3S 800 mAh pack in mine, I did swap out the stock esc for a HK Otter 40 amp (it's overkill I know but there is no esc ventilation I figured higher amped esc would generate less heat).

I threw out the manual as for balance, I believe my manual suggested 35 - 45 mm from le of wing, I placed my CG about where the main spar would be in the wing.

Maidened it yesterday and it did seem to have a tendency to want to balloon but it was nothing some down trim didn't correct. I didn't notice it wanting to roll to one side or the other. I've seen alot of people doing flap mods on these 800mm birds and I think it's unnecessary the gain from the flaps is not worth the weight cost. My AUW is just over a pound and everything but the esc and battery are stock.
Jan 08, 2013, 12:17 AM
Happy safe flying :-)
richard1971's Avatar
Thread OP
@dedstik

I'm using the stock battery 2s 1000mah supplied with the Arf kit, installed it with ar600 rx and dx6i rx, the flaps servo is from my 200 size heli (quite small), seen guys in YouTube adding flaps and it does look good. When I flew my mini t28 ( hand launch) its ok for a few minutes and after I tried to do a loop it tends to ballon and impossible to balance & to gain control back until she dropped to the ground.
Jan 08, 2013, 01:12 AM
Farmer
f.a.r.m.e.r's Avatar
Quote:
Originally Posted by richard1971
Hi,

I'm new to this thread and wondering if anyone could help.
I bought an fms t-28 mini (800mm) used stock batteries ar600 reciever pn dx6i and added a flaps using micro servos, assembled everything, checked controls, 45mm cg from the front edge sides of main wings- everything seems ok. Went to the field (6mph wind) and hand launch her, flown straight then bank left, straight again then some mini acro loop (100ft high), after that she seems to be uncontrollable, trying hard to gain the balance but its impossible, until I dropped her into the ground. Propeller gone and the motor mount slightly cracked which can be repaired by epoxy I think.
My skill level is a bigginer and would be able to fly my e-flite mig 15 and carbon cub...

Queries are:
- is my cg correct?
- bought a 2 blade prop, easy flyer, is it ok?
- is the stock battery underpowered
- any advice and help would be really great.

Thanks,
Richard
your battery must have shifted on you.. what your explainin is exactly what a tail heavy plane does..
Aug 10, 2014, 02:29 AM
Registered User
i have a 2s 1300 battery in it haven't madend it yet .
but cant get it ;s cg right is it ok if it is nose heavy i.m about 45 ,50 mm back from leading edge
and it still a bit nose heavy . any ones thoughts .
p.s i'm running the orange 3axis stabalizer v2 at 50% or should i not even use it

josh
Aug 12, 2014, 04:55 PM
Registered User

Battery position and control surface rates/expo?


Hi,

I have one of these 800mm T-28s and put the battery all the way forward in the battery bay so that the back of it is touching the back of the battery bay/firewall. In this position, the canopy should keep the battery from shifting back.

I do not have flaps on mine, nor do I think it needs them. I did have to add a few clicks of down-trim to get her to fly level, but have not had any issues with controllability. Do you have the control linkages set to the factory default settings, per the manual both on the servo horn and on the control horns on the ailerons, elevator and rudder? Have you tried adding 15-25% expo on the aileron and elevator and setting the low rates on your radio to 60 or 70% to tame the responsiveness of the plane? What throttle setting do you fly at (i.e. are you running full throttle all the time or are you flying around half throttle)?

If you need me to, I will put a battery in mine and determine the CG point and give you the measurement for my plane for comparison.

JPDJR


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