Last log of this heli

Hy guys, yesterday I lost my trex 550l dominator on a crash! This heli from the first flight I knew something was wrong! I just would like to know what was its problem to not repeat it in the future! Just to short the history first I tried to install microbeast plus and the rescue never worked, when I turned it on the heli always had weird behavior like hard aileron and/or elevator input. Never leveled! Talking into beastx forum, the clue was high vibrations! One day I tried a back flip and the heli had a hard left aileron input and almost lost it. The rescue saved the heli this time.
So I decided to install a vbar neo that has a vibration sensor and logs. After I setted it up and checked the logs I never had a vibration or error warnings! But when I tested rescue from vbar I had the same problem, heli had a left aileron, not bad! The second time, when I tested it, I had a hard left aileron and this time I could not save the heli! I attached the last log file so someone could help me! Thanks in advance!

Ok - so i can delete your email.
A bit more patience during the holidays would have been nice.

Anyway ... as we have a high range sensor (up to 200 g) and there are no hints for vibrations etc - i think we may have a failure on other hardwares like static hits on servo wires, defective servos etc. which we can't monitor.

But - to be sure - it would be nice to get the complete log (all flights) of this Vbar - maybe there is something logged previously.

regards (EN) / Gruss (DE)

Rainer Vetter

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First of all I would like to apologize myself but I did not know that would be the same person who answer email and answer for the forum! I am completely new to vbar; sorry!
I would like to thank you for answering so soon and trying to help me! I attached the log for all flights and wrote on it the point where I removed the vbar from my crashed heli. I really don´t know what has happened, but perhaps an intermitent problem, as you mentioned, that was always present when rescue (for both system) was used and one time in normal flight with beastx. Anyway, I hope we could discover the cause of the problem, as I ordered a new heli exactly like the other crashed!

No problem at all!


About the log - i had a look on the entries - but there is nothing which could make me nervous ;-(

I had a very tiny hint about some powerup issues (init retrys at some beginnings) - but not in the regarding flight - and all inits were good with the second try (init ok logged).

But anyway - can you tell me a bit more about the servos and used power supply?

regards (EN) / Gruss (DE)

Rainer Vetter

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Posting and answering - please use a PC and a standard keyboard. Answer all questions fully, take the needed time, don't forget probably requested attachments.

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OK Rainer, thanks. Servos were all stock align´s! BL815H on cyclic and BL855H on tail. My power supply initially was talon 90 but then I changed to CC phoenix edge 120 HV and CC Bec pro at 7,5v. One wire was going to receiver and the other to vbar! That´s all about! But let me know if you need some more information! One thing that I did not have done was balacing my tail blades, but this should be related to vibrations!

I would like to take advance of your knowledge and ask about vibrations as I just have already finished my new trex 550 L assembly. I made a bench test without all blades and noted some values. Does Vbar worns me if vibrations are too much? From the graph I had two peaks: 198.90 Hz (11,934 rpm) and 358.80Hz (21,528 rpm). And at the live display I had a green bar that reached 501. My question is: Is it too much? Am I OK to fly? If I press the vbar against the gyro mount surface (i tried it by hand) I noticed a great decrease on all values! Thanks again for all help and patience and happy new year!!!!

Ok - sounds good with the servos and BEC.

Quote:

From the graph I had two peaks: 198.90 Hz (11,934 rpm) and 358.80Hz (21,528 rpm)

Can you please add some screenshots here?

regards (EN) / Gruss (DE)

Rainer Vetter

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Posting and answering - please use a PC and a standard keyboard. Answer all questions fully, take the needed time, don't forget probably requested attachments.

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Hi, I attached screenshots of the graphs as you asked me! The higher peaks is from vbar without any strap on and the lower one is with a strap on pressing it against gyro mount! There are also a picture of vbar with strap on so you can tell me if it is OK to do that to reduce vibrations. I also attached a log file from the first flight of my new heli (without any strap on). It flyed great except tail that was inconsistent with a right kick and with a very low yaw (right tail left nose). I did not make a trim flight yet. But I think that I will have to mess with advanced tail parameters and I know that I will have to have your help! Sorry!

Well - this is way too high! - Seem to be that the tail rotor or tail drive has some problems here ...

is it with tail blades? - If yes - check w/o. If not - check tail hub, shaft or torque tube and gears.

regards (EN) / Gruss (DE)

Rainer Vetter

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Posting and answering - please use a PC and a standard keyboard. Answer all questions fully, take the needed time, don't forget probably requested attachments.

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This values you see were pretty next on the other heli that crashed! So, I have vibrations, but why a vibration warning does not appear on the logs!? Both helis were new, so I tjink it is impossible that both have the same problem. I think that this vibration could be from torque tube which has only one bearing (like manual). This test was without tail blades, but I have ballanced them with tail hub and shaft. Should I put 2 bearings on the torque tube? I know it is a trex, but probably you have found a problem next to mine! Thanks for all support!

Hi alatuf,

I have a T-Rex 600L but the mechanical concept is very similar between the 600 and 550.

Have you checked that the bearing is fixed a little bit off the center of the torque tube as described in the assembly manual? It must not be fixed exactly at the center of the torque tube since this can cause vibrations.

You may want to remove the tail shaft with the gear and measure the vibrations again in order to confirm that the vibrations are indeed from the torque tube.

Peter

Hi Peter, thank you for helping! After a good search I discovered that it really goes from TT! I took care of not putting the bearing at the CG of TT and 6 cm from it going to the nose of the heli. Even so the vibration was there! I desassembled part to part of tail rotor and changed each part from another trex 550L that I crashed but kept it as a backup. When I was giving up, I decided to put more one TT bearing and the highest peak of the graph simply desappeared! So in this case, another TT bearing was the resolution! At live display from vbar software I got values until 501 with vibrations; now the highest value was 146! I still have the other lowest peak of the graph, but I think it will not disturb my vbar, specially when rescue is activated! What you think!?

Rainer, just to confirm please have a look at this new graph to see if I am having too much vibration or I can fly and use rescue this way! If not, where I have to look at to search vibration now? Thanks!

WOW - i am very impressed! Well done here!!! All far below our limits and - i see a Motor running, thats all ;-)

regards (EN) / Gruss (DE)

Rainer Vetter

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Posting and answering - please use a PC and a standard keyboard. Answer all questions fully, take the needed time, don't forget probably requested attachments.

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Wow! How is good to hear this! I don´t know why align does not recomend 2 bearings for the torque tube! Perhaps that was the same problem of the other heli! Too much vibration, but the only thing I don´t understand is why I did not have vibration warning on the logs!? Anyway, job was done! Thanks for all support! Now I am having a hard job to get my tail to be OK. Could you help me? I think I have to change some expert parameters, but the information on the software is not enough for a newbe vbar guy like me! Should I start another treat or can we go in this one!?

You can proceed here - just fly, watch, describe and ask ;-)

regards (EN) / Gruss (DE)

Rainer Vetter

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Posting and answering - please use a PC and a standard keyboard. Answer all questions fully, take the needed time, don't forget probably requested attachments.

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OK! Thanks a lot! I just flew it today 3 batteries and I saw a slow tail wag. Lowering tail gain it got better but not desappeared! As I read on others forum a put 75 on p and i gain and tried to decrease tail gain, DMA collective and cyclic. The wag got even better but still there. Another thing that I felt was a very responsive rudder sticky input (increased expo to 55, but still somewhat lacking). Before trim flight I got a right tail input that made a very slow yaw. When trim flight was done, a got -100 on tail autotrim! Perhaps I should increase deadband value? With collective inputs the tail blows out and stayed where it went (about 45 degrees). And the worst part was tail stop behavior! It stopped and came back about 90 degrees like a catapult! Tail optimizer was on and I got 30 for each A and B! Sorry but I don´t know the english terms to describe tail bahavior!!!

Quote:

I saw a slow tail wag. Lowering tail gain it got better but not desappeared! As I read on others forum a put 75 on p and i gain and tried to decrease tail gain, DMA collective and cyclic. The wag got even better but still there.

We suggest to increase the common tail gain as first before starting with single parameters.

About the tail ...


This sounds to me like one of those reasons which are responsible for too less tail thrust:

- too less headspeed (how much?)
- too less tail speed (tail/main gear ratio?)
- too short tail blades (which?)
- some slip in the tail drive (check worm screws etc.)
- tail rotor direction and blade mounting (leading control or laging control)

Please post the ragrading answers - and also a image of the tail rotor in center after powerup.

regards (EN) / Gruss (DE)

Rainer Vetter

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Posting and answering - please use a PC and a standard keyboard. Answer all questions fully, take the needed time, don't forget probably requested attachments.

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Rainer, today I read your post and went flying. I increased a little my rpm (vbar e-gov) and returned the values to default, except aceleration: 45 and overall gain: 63. Things got a little better, but were still away to be good!


RV schrieb:
-------------------------------------------------------

> This sounds to me like one of those reasons which
> are responsible for too less tail thrust:
>
It is a trex 550L dominator, all stock!

> - too less headspeed (how much?) 2280
> - too less tail speed (tail/main gear ratio?) Drive Gear Ratio:1:7:3.85
> - too short tail blades (which?) 90 mm
> - some slip in the tail drive (check worm screws
> etc.) I think everything is OK. With microbeast plus the tail was perfect!
> - tail rotor direction and blade mounting (leading
> control or laging control) CCW, the other question I don´t know how to answer! I hope the picture can answer!
>
> Please post the ragrading answers - and also a
> image of the tail rotor in center after powerup.

What I did was a power up and next took a picture from above and did not touch rudder stick! It is in the place when I power up the heli! The position you see in the picture after power up is far away the position that I set the tail up on the setup part of the software! I don´t know if this is correct? But when I power up the heli tail servo is not at its center position!



1 mal bearbeitet. Zuletzt am 07.01.2016 01:42 von alatuf.

The tail rotor seem to be in the wrong basic angle - it is with the torque instead of against it! - But - as the tail lever at the gearbox seem to be aligned ok and also the blade mounting (leading) is according to other images on the web - check the tail shaft length, it could be a wrong (too short) one!

Example on a Logo - but as it is general physics ...

http://www.vstabi.info/en/node/842#tail

Also - if it has the "bad" Align 4.2 gear ratio main/tail - use a speed up geear here. These Align Helis are designed for very high headspeeds (Asia style - very inefficient) to get a working tail ;-( - our Mikados have 4.7 here ...

regards (EN) / Gruss (DE)

Rainer Vetter

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Posting and answering - please use a PC and a standard keyboard. Answer all questions fully, take the needed time, don't forget probably requested attachments.

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1 mal bearbeitet. Zuletzt am 07.01.2016 08:47 von RV.

Sorry Rainer, but this does not helped much! With a 16t motor pinion and 112t main gear what the highest hs that I can reach with gov engaged?

Should I follow exactly my heli manual, or should I follow vbar to setup my tail? For vbar I used the outer tail servo arm hole and increased the linkage lenth to get 2 degrees against torque!

Quote:

For vbar I used the outer tail servo arm hole and increased the linkage lenth to get 2 degrees against torque!

The image posted above from you shows a angle WITH the torque - which is obviously wrong.

I agree that it must be against the torque - but i do not agree that the image shows this situation ;-)

regards (EN) / Gruss (DE)

Rainer Vetter

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Posting and answering - please use a PC and a standard keyboard. Answer all questions fully, take the needed time, don't forget probably requested attachments.

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I do not understand! The main rotor of this heli is CW so tail tendency is to go left from above looking! What is CCW is the tail rotor!

Hello alatuf,

your mainrotor is rotating clockwise.

The torque, which is necessary to do this, gives a reaction to the fuselage of the helicopter, which trys to turn the fuselage counterclockwise.

The tailrotor has to compensate this ccw torque. Therefore the tail must blow to the right side (in hover).

Your picture shows a tail which is blowing to the left.

So you should change your angle for set-up position just to the other side.

Gruß, Wolfram



1 mal bearbeitet. Zuletzt am 07.01.2016 17:44 von Wolfram.

Thanks Wolfram! I did not know about this! I thought the would spin the same direction of mail rotor blades! I have already corrected it on tail setup changing linkage and tail servo arm beyond end points. But when I leave setup my tail servo goes to the position of the picture I took! Is it ok or something is wrong? I just can get my tail servo center position only in setup otherwise it assumes the position of the picture!

To make it perfect:

delete trim flight values and follow my previously posted guide:


http://www.vstabi.info/en/node/842#tail

regards (EN) / Gruss (DE)

Rainer Vetter

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Posting and answering - please use a PC and a standard keyboard. Answer all questions fully, take the needed time, don't forget probably requested attachments.

Für Posts und Antworten bitte einen PC und eine richtige Taststaur benutzen sowie alle Fragen vollständig abarbeiten. Nehmt Euch Zeit, beantwortet Rückfragen in Ruhe und vollständig.
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Hello alatuf,

glad to hear I could help you.

In addition: when you tighten a nut clockwise with a screwdriver, then the nut "works" against your arm and tries to turn your arm counterclockwise.

The nut doesn´t turn your arm clockwise and helps you to tighten herself.

Could you follow me?

For the rest of your problem: follow Rainers suggestion!

Gruß, Wolfram

Wolfam I completly followed you and now I understand! Rainer, I also followed your tail setup and I was a few linkage turns of it! But when I leave setup my tail always go to "that place" of the photo. I think it is not a problem because when you hold your heli to put it on the ground tail gyro will change tail position. What would be great is a way to center tail servo before take off or you always have to ajust tail with stick input to avoid a sudden yaw of the heli! Later I will fly and will tell the results. Lets see

Quote:

But when I leave setup my tail always go to "that place" of the photo

Well - and then - as usual - the Trim flight does it into the right position ;-)

So - do a trim flight and then have a look again ;-)

regards (EN) / Gruss (DE)

Rainer Vetter

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Posting and answering - please use a PC and a standard keyboard. Answer all questions fully, take the needed time, don't forget probably requested attachments.

Für Posts und Antworten bitte einen PC und eine richtige Taststaur benutzen sowie alle Fragen vollständig abarbeiten. Nehmt Euch Zeit, beantwortet Rückfragen in Ruhe und vollständig.
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Für Einzelkommunikation bitte ausschließlich Email verwenden! - PN, Messenger, Chat usw. werden nicht bearbeitet.
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Rainer, thanks for all your patience! Today I went flying and my tail got better! Here is my numbers:

HS: 2300
Gyro gain: 70
Aceleration: 45
P gain: 80
I gain: 60
D gain: 0
Expo: 55
DMA Collective: 22
DMA Cyclic: 8
28 tail optimizer 30
Rudder auto trim: 10

I did a trim flight but my tail position never moves from that photo position no matter what I have done! But anyway I think this is not a problem! Or am I wrong!?

When flying I notice some tail behavior that I would like to get rid of:

I have a slow and small tail wag (on bank 1 I put HS 2280 and gyro gain at 60 and the wag were just a little lower). The wag sometimes can be seen on FFF and bank turns, but it is much more seeing on hover.

When I make a rudder input and then goes the stick to the center the tail stops and back a few times. The stop is not accurate.

When a crosswind gets tail it goes against the wind (yaw) in small steps

Sorry for my poor english! I don´t know the correct or usual names for tail behavior! But I hope with this description you can help me even more!!!

I also attached the log from my last flights and I am having some "raised vibration level" on begining or ending of flight! Should I be concerned about this? Have a look please!



1 mal bearbeitet. Zuletzt am 08.01.2016 22:15 von alatuf.