Added: 3 years ago
From: sirenp
Views: 36,575
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  • I had the same problem, and it was one of my cyclic servos that was defect. It was always moving a little bit, even with no cyclic input. I change it for a brand new one and everything got fixed.

  • Great amount of vibration comes from the main gear. I know you have almost solved vibration (there is always some) but you can try replacing the main gear. Bear in mind they are never perfect. You can see in many onboard vids how they seem to move up and down. Search for Align T-Rex 700E GoPro Hero HD 052.

  • Hey. I got the similar problem though and couldn't verified it till now.

    Thought the chassis was bent, changed and still the same.

    Will try loosening the tail blade grip later.

  • I cant help but notice... that heli has no shadow.?

  • I am agree with Suprec...need more rotation...

  • Too low throtlle curve in normal mode.

    Put it in idle mode with more rotation, and it gonna stop.

  • You're right that increasing head speed wil make it stop wobbling. However, as mentioned below, increasing the head speed may visibly "solve" the problem, but really just transfers it into a different frequency range and thereby might kill a servo or mechanically/electrically stress some part to a failure. It needs to be properly looked at. Balanding flybar and maing blades are the first two things on to-do the list.

  • If wobbling happens when you are decreasing the throttle it's 100% sure to be low headspeed, but if it keeps wobbling even with high headspeed, could really be unbalanced parts (blades, flybar, bent shaft, etc).

    Just a tip: If you're using a good carbon blade, don't worry about their balance, just because they are already balanced. Use a caliper rule to measure both distances between the paddles and its rotor base.

    Hope it helps a lil .

    Marc.

  • @sirenp

    No its just the Trex500, this is the way they are.

    Trex500 loves high head speed.

  • Adjust the gain on your gyro. move to minus until it's stable

  • Did you solve this problem. My t-rex 600 Esp does exacly the same thing. What should I do?

  • Nope, not solved/implemented fully yet. I have since then though increased headspeed when running in idle up (but that only transfers the problem into another, less visible but maybe more dangerous, vibration frequency), and have also tweaked a bit with the pitch settings on each blade. I have not yet balanced them, which will be a problem for this spring.

  • if you're using carbon blades, you don't need to balance them. What's your throtlle curve? Do you have the same problem in idle mode with 80% headspeed?

  • My T-Rex has the same problem, but mine is T-Rex 600 with torque. I don`t know what else can I do. And you, did you solve the problem already?.

  • No I haven't. I'm flying it anyway (when getting a chance this winter). Once spring is here and more flight time is possible I'll have a look at it.

  • @sirenp i think maybe turning down gyro gain a notch or two.

  • @sirenp vibrations are common to all helicopters, even the real ones have significant vibration issues. Don't worry, balance the blades and do all you have to do to minimize the vibrations but even though it looks like you've eliminated all the vibrations, it only means that vibrations are not perceivable and changed frequency. The day you won't have any vibrations on your heli you won't hear the blades spinning.

  • Check out your flybar (must be balanced). After that increase your throtlle curve a little bit.

  • It could be your main shaft is moving up and down.

    Pull the whole head upward and re-tighten the set screw on the collar.

  • Schraub die Drehzahl rauf dann ist es weg. Ist normal beim T-Rex 500 bei tiefer Drehzahl funktioniert der Kopf nicht gut und das Heck auch nicht. ich fliege am Kopf ca 2800 Umdrehungen.

    Gruss

  • hauptwelle angeschlagen vielleicht?

  • Nein, der war dann ganz neu zusammengeschraubt. Ist warhscheinlich die Balance der Hauptrotorblätter. Ich habe sie noch nicht getauscht oder voll balanziert!

  • oh, unbedingt machen! das ist sehr wichtig!

  • problem solved?

  • I had exactly the same problem. I figured out its related to the main blades. Try another pair (perfectly balanced) and the problem is gone!

  • you need to level your fly bar

  • Have you had any 'Static' issues yet???

    I've heard they cause similar problems in the tail.

  • Nope. I put some anti-static spray on the belt and all gears when I first got it last summer, but haven't done anything to it since then. It works just fine.

  • It has nothing to do with the gyro. Sometimes helicopters just do that when they are happy.

  • nice vid mate after building mine it acted the same way :( like you i upped the headspeed abit and prob was solved maybe we should of put in the 13tooth pinion instead of the 12 to begin with? what does everyone think? :)

  • I just finished my T500, doing the exact same thing yours is here. Checked my head speed, found it to be 2300 @ 0 dgree pitch 75% Throt. I've changed it to 80% 0 pitch. This gave me 2500 head speed and solid hover and tail lock. I bet the same will work for you. Good luck, let me know how you end up fixing it.

  • My heli flies like a graceful and powerful beast! rock steady (except a little off-center COG) and no tail bob at all except when batteries are getting low. The tail starts to bob slightly in idle-up when batteries are closing in on the cut-off voltage, which shows to be a good indicator of when to land.

  • it looks like it has too much gain

  • Yes it is caused by too low head speed, speed up man. up the throttle curve !

  • too low a headspeed, increase your throttle curve to as close as you can get it to flatline 100%. Select a pinion so that you get the headspeed you want with a flatline 100% in idleup. This will also make your ESC/motor and lipos run cooler.

  • Needs more gain!

  • It is a speed control issue. Seen many of these with the 500..

  • Umm ... no. How would you think this is an ESC issue? It's oscillating vertically and the motor is spinning at a constant rate.

    This is a classic low-headspeed bobble.

  • Yes I read a bobbing up/down is from a slow head speed

  • You can see from the vid that the tracking is OK. This is not tail wag, it is tail bob, and is caused by too low a head speed. Increase your throttle curve to 100% flat if you're using a 12T pinion and the bob will be gone.

  • or blade tracking

  • Blade tracking is 99% perfect. As mentioned in the info section, it was related to the main and tail rotor blades being torqued down a little too much. Also increasing the headspeed took care of the problem for most. There might still be a slight balancing issue with the blades, but that's tbd. The performance with these countermeasures pretty much took care of the problem.

  • looks like blade balance issue

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