RC Model Reviews

hi as the title says, i just put together my new axn last night and tried to maiden it today. so far the only planes i have flown was the dynam sky trainer and a scratch built sports trainer from mikeysrc. i have also done a lot of hours behind phoenix rc simulator. the closest i could use on it was the easy star but it was only 3 channels.

now to the fun part. i am using a 2200 mah turnigy lipo. changed the esc to a 30 amp one. also changed the prop to 6x4e and used a proper prop adapter. it launched fine but once it was airborne, came the problem.
i tends to pitch up when on power. it glides fine no problem. it may just be me not used to this behavior since this is my first pusher plane. but it is kind of weird feeling. like i feel i have to correct alot compared to my high wing trainers. i could do hands off but only if im on 1/3 power. any higher i feel that i have to "fight" it for a level flight. i have done 3 packs. the first one i made a mistake and hit a small tree. good thing it was only around 3 feet from the ground. second pack was a perfect landing. the third pack i caught a strong gust on final approach and it started to pitch up and stalled. and exciting afternoon for sure.

Is there anything i forgot to check. i did not do any mixing on it. just a standard 4 channel setup.

I shouldn't really answer this (because I have an inability to sustain flight ) but I would check your CG, should be on the wing spar. (Anyone find it different please smack me )
The AXN tends to pitch nose down on adding throttle, yours appears to be opposite this trend so would check the CG and or thrust angle of the motor.

Dennis

i checked the cg on the wing spar and it is actually a little nose heavy which is what makes it weird. i have flown planes with too nose heavy and tail heavy. but this one bothers me. it only pitches up if i apply 50% or more power. i will try to fly again this weekend and see. i have the battery pushed all the way to the front already.

The AXN tends to pitch nose down on adding throttle

Yes it does but only momentarily until airspeed increases then it may well start to pitch up.
Its not very easy to adjust the thrust line on the axn so mixing in a bit of down elevator with throttle may help but be aware, as you open the throttle it will pitch down and adding down elevator, to control the pitch up as speed increases, will make this initial effect worse.

Have you bench tested the AXN through all channel movements, nothing unusual happening with control surfaces when moving the throttle.
All servos, servo horns, links and clevises are firm. Nothing moves unless it is instructed to
The motor and motor mount are secure and do not move under any throttle position, the motor mount has been known to come off.
Your RX/TX is setup for a basic 4 channel fixed wing, no hidden mixing that you are unaware of?

Don't overlook the simple things, most of the time that's it

Dennis

i did just that after i came home that day. went over all the links and horns. made sure that all control surfaces are flush and on neutral position. i did a static test before i maidened it and nothing moves unless i did something on the tx.

the tx is a bone stock 4 channel setup. i am using a turnigy 9x running er9x. no mixing at all. i have have not changed the expo, d/r and trim as well just to make sure i get a feel for it. the last time i used it, i have to trim elevator all the down just to be flyable.

hopefully tomorrow is a calm enough so i could toss it again and see if it improves.

"i have to trim elevator all the down just to be flyable".............
Is this just to position the elevator in a neutral position to the tail plain
When you connect power to the AXN are servo horns at 90deg to the servo body without any trims on the Tx
Can you post a pic of the tail plane showing boom position, clevis attachement and preflight trim position:?:

will post a pic once i get home. i think the reason from me trimming it all the way down was the links for some reason moved. i think i did not tighten the set screw enough on the elevatore servo. already did another check last night just in case i can go flying today.

i was able fly the axn yesterday. more bad news though. after making adjustments to the pushrod and double checking the control surfaces, it was much better than the maiden flight. now to the bad news. when i was trying to land it, the elevator servo seems to only want to go up and the rudder seems stuck full right. i have to use throttle to get it low enough so it wouldn't be a catasphrophic crash then ditched it maybe at around 10 feet. nose got a little bent but that is okay.

now to the damage report. rudder servo is stripped for some reason. it just whines and the arm won't move. the elevator servo on the other hand is dead. i just wished i bought the kit version with just the motor on it since i have a lot of orange 9g hk servos at home. i just thought it will be easier to buy the arf and just swap out servos once they quit. well lesson learned.

My rudder servo is also stripped, its one of the Orange servos Bruce recommended.
Still 100% flyable though, just no rudder.

So probhably just a bit of bad luck for both of us. Cheap servos: you take the chance of failure.
I now have to cut the old servo out : any suggestions on this anyone
Im not that keen on putting an Orange servo back in, the HXT900's are going through a bad batch(HK forums) , any suggestions?
Is it worthwhile/needed to put a metal gear servo in ??

(sorry to hijack your thread)