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CopterX250 turning into an Align model

robocog 10th September 2015

Confusing situation

Flew a pack on the CopterX250 FBL – all went fine, landing was soft …and landed on both skids at the same time without tail striking grass or anything untoward, hands shaking and feeling really quite pleased it landed back on its skids and nothing went wrong I was proper chuffed with myself

I needed to adjust the tail as it had slight drift when not in heading hold mode

I understand this is perfectly normal and only requires an adjustment on the tail servo’s pushrod length to get it so it no longer drifts when in rate mode (and should, in theory at least, also give the servo an easier time of it when it’s in heading hold mode)

Unfortunately I couldn’t recall which way I was having to compensate with the rudder stick (there’s plenty going on when hovering these little beasts in a small area! – esp for a nervous newbie like myself) – all I could remember was when it got switched out of heading hold mode and into rate mode It started to slowly spin…naturally the heading hold switch got flicked straight back on and the rudder got pointed back to me!

Not a massive deal I thought – chuck another battery in and flick it to rate mode and see which way it wants to drift- after all I just flew a whole pack without incident…

…Unfortunately the heligods had other ideas…

On applying gradual throttle for takeoff the tail shook quite violently – and after the first 250 heli I had got into the habit of exploding the tail booms and chucking them into the spinning rotor blades I immediately powered down and gave the machine a look over and check what had become loose/gone bad

The tail box screws had not only backed off (hidden behind the vertical stabilizer) but had also ovalled the holes and pulled some of the threads out for good measure….sigh – despite being careful to torque them up without stripping or snap heads off… and used threadlock for good measure

One of the bearings in the tail box felt ropey, but now the box had no usable threads left on one side it was pointless replacing just the bearings

Align tail section ordered as eHirobo don’t have the black ally tail drive to sell me (only available in blue)

I also bought a new Align tail slider (looks like a heavier duty part TBH) , 3x Align belts and a pair of neon KBDD tail blades (not being 100% certain I could mix and match Align and CopterX parts) – also some Align carbon main blades and a Lynx HD feathering shaft damper – noticed on the inspection to see what was causing the vibes the feathering shaft gave the impression it was bent when I twisted the bolt head- despite the shaft itself being 100% straight upon removal and cheking – then I noticed it was the rubbers making the blade holders sit at different angles as the shaft was spun…not idealIMAG1708 (Medium)

I also bought a set of interesting swash to blade holder turnbuckles with clockwise and anticlockwise threads each end so the blade tracking can be adjusted with accuracy and precision that 360degree adjustments will never allow (and all without even having to pop the ball joints off!)

Unfortunately the rod lengths are too long so they are unusable for this helicopter… without either modification or some fudging of the swash level (shorter swash to servo rods would work)…one for a rainy day to try and find shorter rods

I balanced the Align carbon blades and bolted it all back together (leaving 24 hrs for the threadlock to cure)  – got as far as spinning the bird up to the point it hovers, no detectable vibration… and the tracking seems spot on – so it’s all good 😀

…feels very direct immediate and responsive compared to the rubber dampers and plastic blade setup it was running…but I STILL need to pluck up the bottle to switch out of heading hold mode and correct the rate mode tail drift

One for an indoor flying site with plenty of room or completely calm day…and a healthy dose of ‘go for it’!

Categories CopterX250 FBL, Radio Control Tags Radio Control
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