Some 300x problems and solutions

[Mvflyer]

I own two 300x's and just rebuilt one of them after flying it into the ground. I am new to larger helis having flown only the Mcpx and 130x.

Thanks to xpantz and others advice I was able to rebuild the 300x ... Thought I would share some learning for the past couple of days of flying and repairing.

1. After my rebuild the tail was spinning out of control . For the life of me I could not figure out what could be wrong. One night I was reading a forum on helifreak that mentioned the direction of the tail rotor should spin towards the bottom of the heli ... That is that I'd it hit the dirt the rotor would fling it towards the heli. Sure enough my tail rot was spinning in the wrong direction because I reversed the belt on the main hub. Problem solved.

2. I flew my other 300 today. It was flying great but I had a small crash that seemed to only crack the skids. Flew it again and everything was fine until I switched to stunt mode and then applied positive pitch. The heli slowly floated back down and would not climb. I talked to a friend who suggested that the one way bearing was shot in the main hub...sure enough I was able to hold the main gear and move the blades in both directions with little or no resistance. I need to replace the main hub and should be good to go.

3. Flew my rebuilt heli and have noticeable tail wag. I am away in Florida for about a month and the heli was flying fine back home in Massachusetts. One thing I had forgotten is that this tail wag problem was present before my crash on my first flight in Florida. In other words the heli was flying fine up in the cold weather of Mass. But didn't seem to like the warm weather... Someone suggested that the tail gain needs to be adjusted as moving from a cold climate to a much warmer climate could effect it how it behaves....I haven't made this adjustment yet but it sounds like a theory...has anyone heard this before?

mvflyer


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[xpantz]

Maybe the hot weather has softened your tail belt... check tension.

You can try turning the gyro up to see if that makes a difference... but if you turn it up and it makes no difference.. start to look for something else.... also if you get a shudder from the tail in a hard turn after increasing gyro, then turn it back down until the tail does not shudder.

[petedee]

And just one point, the 300X does not have a one way bearing, probably means snapped main shaft.

[sn00p]

Originally Posted by petedee

And just one point, the 300X does not have a one way bearing, probably means snapped main shaft.

or jesus bolt :-)

Tail WAG is usally associated with Gyro gain but....

I would check that you have No binding on the servo horn/disc as well as the connecting rod and tail case links and shaft first just because you had a crash so it is likely you have tweeked something... quick visual and then try moving with TX powered up and throttle hold on. Use rudder stick left and right and check the servo isnt binding and making lots of noise at the end points or straining.

I would also check when heli is powered off that the tail servo gears are all in good shape by turn it full extent in both direction carefully by hand (POWERED DOWN) and making sure your teeth are all good and not stripped (felt as an uneven notch when moving by hand)

If this doesnt fix the issue then i would look at lowering the gyro gain increments of 5 at a time but it shouldnt need to come down too far from the manuals settings unless there is an issue. maybe a max of 15 - or + from stock setting (dx6i i think is 65 from memory but considerably less for DX8)