X5-lite tail driving me BONKERS

[sp00fman]

Hey thanks. I will check them again. i noticed the screws holding the gears backing out after flights. Used loctite on the bottom of the screwheads as per TDR manual. I think they are still snug but i will disassembe them to make sure.

I am going to turn gov off for them moment, Im even considering building up my spare kit and move the electronics over.

[craigjell]

Hi, I've been following this thread on and off - did you finally manage to solve the issue?
Was it the tail case bolts backing out or governor?

[sp00fman]

Had a break from fixing it after it wanted to plow itself in due to the vibrations.

I am working on my second mini-protos now. It is so smooth and vibration free you can barely hear it hover 3 meters away.

In the meanwhile i have build up my spare kit as a test rig. Motor and ESC only on it.
It seems less prone to the vibration problem with the spare parts i put on its tail to evaluate the test rig.

I am ready to transfer my long boom+all the high grade parts to the test rig.
That is, Logo400 tailshaft, X5 CNC intergrated tailcase, metal X5 tailgrips, my new orange X7 Lynx tailfin, 92mm carbon tailblades (the low weight really reduces the vibe problem).

If it tests out good and the problems reoccurs when i put it back on the real heli, i will know the cause is in the frame somewhere, then i would have to build up the test rig as my airframe.... oh well, we shall see.

[sp00fman]

Tail on the test rig was smooth. The tail slider is also very smooth when spooled up so the tailservo will have an easy time. i suspect the CF tailblades have a lot to do with that. With plastic blades there was a lot of force needed to get it off 0-pitch. (not binding)

Put the assembly back on the the heli and it seems good.for now. Will have to see how many kids are throwing firecrackers around tomorrow morning to judge if i have a test flight window. I cant concentrate with all the explotions artound me and the thread of being bombed while flying.



Heres some pitcures of my hopefully completed heli. That one sexy back end, innit? should be, as its the most expensive part on there... including the airframe

[sp00fman]

Went on the HF chat the other day and someone said the problem looked like the Trex700 tail hum. The solution to that is getting Rail carbon tailblades. Could not find the smaller ones so went with he 95mm ones. I intend to keep headspeed below 2200rpm so i assume this size is good.

Seems to be a bit smoother than anything i tried on the bench before. Went with a test flight and nearly destroyed it because i got into a wag of death, Went a bit overboard with the tail gain.

Yesterday did another overhaul, found a problem in the boom supports. The ends are not glued in the rod and developed some play. Fixed that, connected the struts together and made a guide for the pushrod. I'm just back from the field with my first decent flight on this heli. I even started loops and and elevator flips later in the flight. It still has a little nervous wag, and vibration log shows "raised vibration level" I might be able to tune the wag with the PID gain settings.

There might still be some vibrations from the tail. these blades cost me €33,- shipped and they are not perfectly balanced. I put a small about of tape on one blade to make it run smoother, but i am considering returning them. For this price i should not need to balance it out myself.


Oh well, at least i can start tuning the FLB controller now. Sound of the heli is super nice. Weight of the heli is 2200gram with battery now. with the 525mm blades it feels plenty floaty. Nanotech 6s3000mAh 25-50C is not holding up too well. slightly puffed already after this 4:30 flight.
Collective response is a little bit softer than my Hurricane 425mm @ 2800rpm (2100gram)


Getting my hopes up now.
Flight video might follow soon.

[sp00fman]

Well, was still going back and forth with the tail on this heli. flyable, but not perfect yet.

I think i finally nailed it.
Received a new tailshaft made out of an ejector-pin a fellow pilot drilled a hole in for me. Its the tightest tolerance OD shaft i have now. Gaui X5/hurri shafts are too thin, logo400 a little better, but not perfect. The tailshaft alone did not fix it, it just a little better.

Got everything perfectly balanced and super tight on the grip bearings. Had to put a piece of tape on the outer radial bearing in one of the CNC tailgrips, as the grip ID was machined too big at that spot -gaui quality...,
Had to file the thrustbearings OD a bit to be able to place them back in the grips, sanded the CF tailblade roots so they lead/lag very smoothly when the blade bolt is tightened lightly....


Now it runs vibe free even in idleup2. Still noisy, but expected with 95mm blades at 10.000rpm. It is just the wind now, not the airframe. Pushed the tailslider by hand and it feels very smooth spooled up. Almost blew a potplant on the other side of the room over and annoyed my wife sitting on the couch in front of the TV.... Epic

Still have to fly it again but it has never run this smooth before.

My conclusion is the tail needed the light tailblades to work, and be tight but very smooth in the grips so the blades lead and lag correctly. The vibration was most likely caused by aerodynamic back/forth motions together with the tailblades not lead/lagging equally or the tailblades somehow not tracking, setting off the vibration that increases the tracking problem.


Have to wait a bit to test fly it, in the meanwhile am fixing my HK250. It is a p.i.t.a. but is almost a relieve to work on compared to the Hurry.

[sp00fman]

Aaaaaaand....it works!


Put 5 flights on the heli today. With different headspeeds and tightened the belt half way there was no sign of the dreaded tail hum/extreme vibration.

It is taking me quite some effort not to brown my pants flying this thing, but after a few packs something started to click and started to enjoy it a lot! Im not gong to abandon the 450 size anytime soon, but the bigger heli is showing its strengths. Still, the Gaui main head is a POS IMHO, might look at a X5 head in the future. First will fly the snot out of it to see how it holds up.

Hurricane 550 on a windy day. (5 min 14 sec)

[Jerrymac]

Glad to hear that you finally got it sorted out. Seems like it took a lot of work. I have 4 Hurricanes and haven't really had any tail problems with them yet.

[milliotseb]

Nice that you got it fixed

When you have time, could you make a summary of things you did and were effective. I will read again this topic anyway as I have some tail issues on my 475mm blade Gaui

Is the logo 400 tail shaft easy mod?

For me, it seems that light 77mm tail blades have made problem worst compared to KBDD 82mm. I will look for the smoothnest aspect next time.

[sp00fman]

The Logo shaft was a direct fit.
I had a cheap set of Chinese CF tailblades and they were terrible. The Rail blades i have on now are also terrible because they cost €30 shipped.. around $40. crazy. at least it did help.