Banging my head against the wall trying to figure the cause of the hiccups on my Trex-450. Hiccups started after crashing and replacing the tail boom and tail shaft and main shaft and feathering shaft. Closer inspection revealed servos were randomly glitching every 10-20 seconds when rotors turning. 2.4 GHZ spread spectrum receiver and transmitter - doubtful it was outside interference - tapped and thumped and banged on the receiver - no sign of intermittency. Defective receiver? Antenna too close to motor? Motor noise? Tried rerouting motor and ESC leads – no help. New thought - belt going around and around inside metal tube - Van-de-Graaff generator effect? Disconnect belt - throttle up - hiccups gone – headache gone. One question still not resolved - why didn't it have hiccups before the crash? What was different? The new tail boom was a “generic brand” instead of the Align. Half price – both aluminum - looked identical. Generic brand fractionally less in diameter required 10 mm strips of masking tape on each side of the tube for tail boom housing to tighten down on. Was the tape acting like an isolator and letting the boom build up a static charge ? Or did it always have the hiccups and worsened over time and just never noticed it? Replaced drive belt. This one was made of Kevlar. Maybe not so sensitive to static electricity? Spin-up again - hiccups gone. Same question remaining - why didn't it have hiccups before? In any case the new belt cured the hiccup problem. Re-did all the servo cabling to make it pretty again - retested - and passed with flying colors - so to speak. Anyone else have similar problems?

Thats strange since you were on 2.4 but I had the same on FM and adding armorall to my belt stop the glitches.
In your case if all was the same and it started glitching after a crash it could of been a loose connection a crack electronic board, a crack circuit in ESC or RX.
Its hard to say unless you change one item at a time until you find the faulty piece.

From what I have been reading because I have just gotten a T-Rex 500...
the Van-de-Graaff generator effect is because the 500 has a plastic tail and
the boom goes into a plastic housing on the main frame.

The 450 has metal tail... metal tail block on the main frame... so supposedly
Van-de-Graaff generator effect is eliminated. But you said you taped off both
ends of the tail boom.. thusly insulating... and isolating the tail boom so maybe
the Van-de-Graaff generator effect is now possible.

Some people that have been talking about Van-de-Graaff generator effect in the T-Rex 500's
are coat their nylon main gears with Static Guard... the generic stuff and say that
eliminates static build there too... it's cheap stuff and it wouldn't hurt. They spray it into a cup
and use a brush to apply.
On the 500's they are also grounding the boom to the main frame... there is a lot of discussion
about this http://www.helifreak.com/showthread.php?t=61205

You might consider replacing the tail boom with a proper fitting one that you don't have to tape off
the ends. Your old belt may have been frayed enough to cause extra friction and thusly the
Van-de-Graaff generator effect.

Spraying your belt there are lots of discussions on this too... I use "pure" silicone spray.

(and if I have misspoken here... please be easy on me as I am a noobie... one year flying.)

Walkera 22E - Copter X 450 - T-Rex 500 (all electric).

I should have looked before jumping to conclusions - only noise is motor noise and tail booms are all alike. Thanks Rob for pointing me to the discussion thread "static is #1 issue". As in everything else in this forum - my questions had been answered - probably before I knew how to spell RC.