Need troubleshooting assistance with Raptor-short video clip

[KefirHeli]

I recently completed installing a conversion kit, converting my Raptor 30 to a Raptor 50.

In the build I installed a Red Line .53 Thunder Tiger engine.

Two issues that I am having a problem with:

1. When I start the helicopter up, there are times where the main gear sticks as needed and tension begins to build on the main rotor head as the engine and clutch are engaged. There are other times where I will start up the helicopter while holding the main rotor head and with my placement of a little resistance on the rotor head while the helicopter is started up, the main gear slips and runs freely with no power being engaged to the main shaft to spin the main rotors.
What is the potential problem here? What is the proposed remedy? At times it works fine at other times it slips; has it anything to do with the clutch and clutch bell?

2. The helicopter will not spool up. As soon as I get to mid-stick and slight positive pitch of the main rotor blades begins, a frightening "WHOOP!!! WHOOP!!!" Sound comes from the main rotor blades (carbon fiber).
I have checked for accuracy of pitch on both blades with a pitch angle tool and everything is exact with 0° at mid-stick on both blades. I am really lost on this problem. My throttle and pitch curves are all pretty standard; throttle pitch being a linear line and pitch curve starting at 30% and rising.

[KefirHeli]

bump

[DT75]

Could not get the YT link to work...

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Have you flown it as a .30?
Mechanical cyclic and pitch setup is not necessary to touch at all in a conversion.

[755 robert]

Link not working
A couple things come to mind,your clutch liner has come loose from the bell or a broken tab on the clutch.When you take the motor off also check that the clutch has not come unscrewed from the shaft..
Good luck..

[KefirHeli]

Hi Fellas!

Although I made a similar posting a couple of days ago, I still haven't resolved this issue that I am having.

I need everyone to really put their heads together and help figure out the cause.

I'm flying a Raptor 50 V2 that I have just completed rebuilding and although the engine is working perfectly (Thunder T Redine .53), the helicopter will not elevate.

Here is what's happening:

I fire up the helicopter (start up is a nonissue) and begin to slowly increase the throttle until I'm just past mid-stick. Once I reach that point, positive pitch begins on the main rotor blades (obviously ). The pitch I would estimate is about 3 to 5°; AS SOON AS the positive pitch begins I get this frightening, " WHOOP WHOOP!!!!" sound coming from the main rotor blades. With my last experience, that "WHOOP WHOOP" sound stripped my elevator servo gears! By the way, the WHOOP sound is coming directly from the main rotor blades cutting through the air, wrongly, I imagine.

I have done the following in an effort to correct this problem to no avail:

I have quadruple checked accurate pitch settings for both main rotor blades with a pitch angle tool; everything is exact on both blades.

I have swapped out the broken gears in the servo of the elevator.

I have made sure that RX battery is fully charged.

I have tried correcting the problem by swapping out main rotor blades, using both carbon fiber and Woodies. Main rotor blades and tail plates are spinning in the proper direction and are NOT installed incorrectly.

I have gripped all servos tightly and made sure that there are no stripped gears internally.

All parts on the helicopter are nice and tight and the fly bar paddles are balanced and level as they should be.

I have made sure during spool up that all transmitter inputs are responding accurately, which they are, including a very stable tail.

Upgrades that I made to this bird that I do not think or contributing to this problem are: new hardened hollow main shaft, new feathering shaft, new flybar.

*** A little note, when I was doing the rebuild I noticed that the fly bar seesaw was spinning well on the fly bar, but not as smoothly as it used to. I do not have any metal parts installed on this helicopter other than a metal swash plate ***

*** During spool up I am noticing that the fuselage is wobbling a little more than it should AND used to. ***

*** Could it be that I perhaps have tightened something too tight on the elevator assembly? ***

PLEASE THROW AT ME ANY AND ALL IDEAS.....FLOOD ME WITH SPECULATIONS!

HELP HELP HELP HELP!!!!!!!!!!

Sincerely,

Kefir =)

p.s. I would shoot a short video of the occurrence, but it's downright frightening, the sound of the main blades cutting through the air inappropriately during spool-up!

[Bob O]

A video might help at this point.

Like put the camera on a tripod or something at blade level, not too far from the heli (not too close either) and spool it up.

Also we can't help with your mechanical setup if we can't see it. A quality video always helps us to get the best idea of what the problem is.

[KefirHeli]

Bob O and all,

Thanks for giving this matter attention. Here's a video that gives you somewhat of an idea....Just my effin' luck, as I was filming the spool-up the antenna got in the way of the shot, slighty. But you still get a good idea of the issue at hand.

In the video at: 3:49 sec to 3.56 sec, notice the wobble in on the landing skids. I stopped just short of the " WHOOP" sound from the main blades, as the heli would go flying out of control if I gave too much throttle.

Transmitter shows Raptor 30, but it's a 30 that was converted to a 50, so all parameters should be fine there. Flown this Raptor 50 plenty.

Only tranmitter input given is throttle/elevator

Main Rotors: Wood

Thanks again!!!!!

Kefir

[KefirHeli]

Additional Video: Listen and view 43-44 seconds into the clip

video 2012 06 30 15 02 58 (0 min 57 sec)

[Bob O]

Weird.

Have you flown this bird? Do you have a larger area to work in?

What is your pitch curve?

[KefirHeli]

Hey Bob!

Thanks for getting back to me.

I have flown this bird endlessly. Since the rebuild, right as of this moment, I have installed a new main shaft, new feathering shaft and a new Redline .53 engine.

A few things that are coming to mind here, if I could get your assistance:

1. Since this is a Raptor 30 V2 that I converted to a Raptor 50 V2, I'm thinking that maybe the .53 engine is just too powerful for the components of this heli.

2. Although the wobble most likely is coming from something to do with the bird's inability to elevate, perhaps something is bent? I guess I should roll the shafts.....what a pain to disassemble it all again.

Here are my throttle and pitch curves in NORMAL mode as I've been testing in:

Pitch curve NORMAL: 20, 40, 50, 70, 90
Throttle curve NORMAL: 8, 30, 55, 75, 100

Thanks again!

Kefir

[Bob O]

Have you tried lifting off?

In the second video, did the negative pitch come before you reduced the throttle stick?

[burntclutch]

Check the one way bearing in the main gear assembly is correctly lubricated
Check that the trust bearings assembly in the main rotor hub is correctly installed
Try changing dampers to the red ones ( 80 durometer )

No your motor is not to strong , I am on a 55Hz
Good luck

[YBNORMAL]

The throttle linkage doesn't look ideal. It looks as though the servo travel (linkage wise) starts at 90 degrees from the servo/throttle plane at low(or high) carb position, and then goes to one side for the whole travel of the carb. That could be causing some resolution issues for the throttle throw. Which may make the pitch/throttle interaction wonky?

May not be "the" problem, but since I/we don't know whats wrong, I like to start weeding out the issues I know aren't right.

YB

[tr911]

Strange, how much positive pitch do you have at mid stick? The DX6 has a monitor mode in the setup. Put it in monitor mode and move the ptich/throttle up to mid stick in the radio and make sure everything on the heli matches. You should have about +5 degrees at mid stick (thin side of the main blades pointing down).

[fultonr]

I think your throttle curve is too steep. I run a governor so I forget the exact setting my DX9 is set to but it is somthing along the lines of
0 (or 8)in your case, 30, 45, 62, then 100.

So the middle stick position is less than half open and the last little bit of full throttle gives gets it up to 100%. I will double check the settings tonight and get back to you.

So I think that your headspeed is way to high without you having enough pitch on the blades to slower them down. At mid stick you should have about 2 deg of positive pitch (that is if you setup the +10 -7) for normal mode. At Idle up that is different because of the +10-10 settings.

[Bob O]

Originally Posted by tr911

Strange, how much positive pitch do you have at mid stick? The DX6 has a monitor mode in the setup. Put it in monitor mode and move the ptich/throttle up to mid stick in the radio and make sure everything on the heli matches. You should have about +5 degrees at mid stick (thin side of the main blades pointing down).

The answer should be zero degrees at mid stick. The heli should be mechanically setup for a linear pitch range, ie: zero at mid-stick. Then adjust the pitch curves to suit your style as to whether you want to hover at mid-stick or not.

But back to why it won't lift off. Make sure you have a positive pitch range that at least gets to 9 degrees. Your throttle curve should be something like 0-40-60 if you're just going to hover it, but that assumes zero degrees pitch at mid stick.

The question remains, has this bird actually flown?

[KefirHeli]

The bird has been flown endlessly....Flown with an O.S. 37 and O.S. .46......Rebuilt this bird as of late and installed a Thunder Tiger .53 in it now.

All of you have provided quite a bit of information to work with and I will start with the mechanical tips first and progress to transmitter/receiver set up tips.

Let the disassembly begin!

To quickly answer a question, I have not attempted to lift off with the helicopter in its present condition. Just as you pass mid-stick and slight positive pitch sets in, the sound of the blades cutting through the air gives you a clear indication that if you push that gimbal stick any further, prepare yourself to collect disintegrated pieces!

[kiwibob72]

Originally Posted by KefirHeli

......... Here are my throttle and pitch curves in NORMAL mode as I've been testing in:

Pitch curve NORMAL: 20, 40, 50, 70, 90
Throttle curve NORMAL: 8, 30, 55, 75, 100

Thanks again!

Kefir

Based on my own 50 experience with a Dx6i, your pitch curve should be (from position 3 onwards) 50, 75, 100% in normal flight mode (ie linear).
Your throttle should be started to be tuned from mid-stick as approx 50%, 60% then 100% as a starting point. You will need to fine tune those 3rd and 4th positions (50 and 60%) to ensure your not over or under reving the head as your motor tune and climactic issues will be unique. As an example, my summer and winter setting for positions 3 & 4 on my throttle vary by 5% just due to cold and air density.
My midstick position is ALWAYS zero degrees pitch, regardless of flight mode, and my pitch curves NEVER change with seasonal conditions, only my motor curve so I ensure a flat as possible head speed 'curve'.

[KefirHeli]

Originally Posted by kiwibob72

Based on my own 50 experience with a Dx6i, your pitch curve should be (from position 3 onwards) 50, 75, 100% in normal flight mode (ie linear).
Your throttle should be started to be tuned from mid-stick as approx 50%, 60% then 100% as a starting point. You will need to fine tune those 3rd and 4th positions (50 and 60%) to ensure your not over or under reving the head as your motor tune and climactic issues will be unique. As an example, my summer and winter setting for positions 3 & 4 on my throttle vary by 5% just due to cold and air density.
My midstick position is ALWAYS zero degrees pitch, regardless of flight mode, and my pitch curves NEVER change with seasonal conditions, only my motor curve so I ensure a flat as possible head speed 'curve'.

Fellas!

I want to thank each one of you for giving my problem attention and helping me troubleshoot. I took notes on each one of your recommendations and WE finally got the bird back up in the air in a beautiful and stable hover. Although I will not know precisely what the issue was, I switched out most of the parts recommended (since I had all of them as spares) and made a slight adjustment in my throttle curve.

Here's what I did.

Switched out:

spindle shaft
Both main rotor holders w/ entire bearing assembly


I also tightened all linkages and hex screws in the head assembly and was able to get rid of a little slop that I noticed coming from the main rotor holders.

Most of the recommendations given for throttle and pitch curves were existing in my transmitter with the exception of my throttle curve at mid-stick being 55% and so I adjusted it to 50% instead, unsure if that contributed to the troubleshooting. Mid-stick PITCH is: ZERO degrees on both blades. Positive Pitch set to: 9 Degrees and Negative Pitch is: 7 Degrees or so.

Having built and rebuilt Raptors so many times, it was driving me crazy how I just couldn't figure it out!

All in all, all of the above was performed on the bird and it's now hovering nicely. I will be taking it out to an open field to do my first test flight today w/ the new TT Redline 53 engine I installed.

When one of you has a moment, please take a look at my video to address a couple of concerns since I noticed that the MP5 muffler gets hotter than hell and I have concerns that the clearance between the mainframe and the muffler is too close, as well as the muffler & landing skids clearance. Furthermore, I am aware that Nitro fuel creates a mess, but after my first hover with the bird it's drenched! - Typical with this engine/pipe setup?

Please give me your opinion and recommendation.

Thank you again, all of you!

Kefir

[kiwibob72]

Mine only gets really filthy when hovering low to the ground for too long. Yes it gets oily but not too bad. As for the pipe issue/concern, would adding a few extra exhaust gaskets give you enough clearance for peace of mind?
As for the throttle curve with the Dx6i, adjusting the three central points on your curve (2,3 & 4) is how I work to keep as constant a head speed as possible without a governor, it takes a bit of time, but for me, I found it was worth the time taken! (small % changes to each point = big differences in flight characteristic). The aim is not to hear a rev change as you increase pitch.