My feathering shaft woes and my E7SE

[eobie]

I agree with you 100% with what's happening.

The truebloods with stock shimming did the same as the stock dampers. Not until it had 1.5mm at the damper did they hold up. Truebloods own instructions said to run between 1-1.5mm of shimming at the damper.

Like I said before Matt, if the stock damper extended past the head and instead of a small od shim that is supplied a large od shim was used I don't even think we would be having the conversation. The small shim puts all the compression at center, instead of spreading the compression over the whole damper.

The way it sits now, at least on my three machines...2 n7's and the e7, the shim is almost sitting inside the head.

I tried the tape thing, I couldn't even get the damper in the head without the tape pushing right off.


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[eobie]

I also want to apologize. It is not my intention to bag the machine. I want it to work.  I've been lusting for a brand that had both nitro and electric that shared many of the same parts....excluding align.

I have a grand worth of spares....I have an interest in making this work.

Maybe I should not have made this post at all...I was just hoping that someone has been though this and resolved it.


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[Matt Botos]

"Over" Compressing the dampers via shims does two very bad things.

1. Puts unwanted tension on the radial bearings and thrust bearings which is why we hear your helicopter fluttering badly during flight. The fluttering is the blades coming out of track which with heavy loading can also cause issues like you are seeing.
2. Drives the shim into the head block.

Taping the dampers works. Here is how....

1. Clean the dampers with windex or something of that nature. Dry thoroughly.
2. Use scotch tape or packing tape that has a decent adhesive.
3. Carefully insert dampers.


Thanks,

Matt

[Rob Cherry]

Matt beat me to it. The dampeners aren't designed in a way that you can compress them and expect more stiffness. They are already a hard rubber compound (durometer of around 90) and only distort as you compress them beyond the stock setting. Solid dampeners of stiff compounds don't behave like o-rings that compress/expand in addition to being distributed over a set of 3 or 4.

A little trick I've learned is that most if not all of the shims have a slightly rounded side and a flat side. Install them so the rounded edges are towards the dampeners.

Second, the truebloods are even more susceptible to damage and distortion when compressed because they aren't even rubber. If you are compressing truebloods enough to trim off material from a moving shim your radial bearings have to be extremely tight if not completely binding. After you've tightened the spindle bolts disconnect the pitch linkages- the grip should spin nice and free without any binding or drag.

Third. I've attached pictures from dampeners run hard in my 716-bladed machine. The truebloods (left) barely have an indentation, b/c they aren't designed to compress. They were pulled because they were too stiff at low RPMs. The stock ones (right) were pulled after about 30 hard flights. They show signs of compression, but just a little. And yes they show signs of wearing but not to the degree of yours. They've since received 2 layers of clear tape and reinserted.  A video of the heli and how it's consistently flown is shown below. Collective is at +/- 15 , 2150 on the head, Vbar with pitch pump (40) and paddle sim (40).

The biggest thing to remember, we're here to help you figure this out because something isn't right.

https://www.youtube.com/watch?v=2ezcrI9BPOo
https://www.youtube.com/watch?v=HOI8mhGyMAc  (The fun beings at about 1:35)   

[eobie]

This is where I am confused. I am destroying the dampers with stock damping. Are you telling me to add tape and use stock damping, or use tape with less than stock damping.

The fact that yours are not damaged with stock damping and no tape is disturbing to me since in my machine they are destroyed in one flight. Reading your post I'm getting that you didn't add tape until you had compression already.

I'll try whatever you recommend, just please clarify.

[Rob Cherry]

You've brought your street car to the track and need to fine tune the tires to match driving style, stock settings are provided to suit a wide range of "drivers".  While driving on the track expect to replace your rubber MUCH more often than driving on the street, yet you still need to be sure to run the correct tires and pressure regardless.

It would appear that your compression is more than specified, please verify with digital calipers that you have the correct shim inside the grip: 0.5mm, and only one 0.8mm shim next to the dampener.  If there is axial play in the grips where they may slide a hair, try the 1.0mm shim.  There should be 3 sizes: 0.5, 0.8, 1.0.  Let's start there to make sure you don't have any over-compression then work in more by adding tape if you need to.  Clear packing tape is the best, sticks like mad and has a glossy side that when greased slides great!


But... with your flying style you should also be able to use the truebloods, that's what they are designed for. You just need to verify they are not compressed at all, your main grips should rotate/spin freely, mine almost rotate under the weight of the grip arm when disconnected.  The truebloods may need a 1.0 shim or 1.3 (0.5+0.8 ) because they are molded shorter than the stock rubber.

[eobie]

Ok great. I can say that when I had the truebloods were in there they had a 1.0+.5 at the damper. There was NO binding in the radials and the grips were smooth. Problem was the damping was too tight. The dampers held up, however.

With just the 1.0mm shim installed at the damper the trueblood was getting mangled.

I will try your recommendation of a total of 1.3mm at the damper. Might be a few as I wont have much time over the next couple of weeks. Also going to try Ralph's system..

Thanks for all your help, Rob.


Ed

[Rob Cherry]

Careful with the FBL system, they are only about as stiff as stock, but with LESS allowable movement of the axle because of the delrin inserts. That system is to fine tune the head for pilots who want something more custom matched to their flying style and may not fly hard 3D OR maybe they fly with less aggressive inputs as witnessed in your video. Matt's setup is designed for a broad range of pilots and allows maximum axle angle, Truebloods for hard 3D /high rpm, FBL to tune your dampening at stock or softer levels but has limited axle travel. Hope this helps!

I'm currently running the FBL setup in a few of my machines, tuning each setup to my flying style. I have yet to run into troubles but I see your flying has more aggressive/combined inputs.

The biggest thing to understand is that Hard 3D doesn't mean the machine is flown with less precision and overly aggressive inputs.  I'm not bashing your flying, just trying to point out that any machine of any brand can and has been maimed in flight due to pilot inputs. Before I flew Synergy, I was crippling machines left and right, I thought the machines were at fault until I realized my "hard" flying was indeed hard but also not good.

A car may have two pedals, sometimes 3 and a shifter...but that doesn't mean it's ok to press or engage any combination of them at will, or randomly, or in any way the driver deems appropriate at the time. The more power and capabilities the car has, it requires even more refinement of inputs and respect. F1 cars are far from just mashing down the go pedal and buzzing around the track until you cross the finish.

Rob

[eobie]

Lol. I know exactly what you mean. Never said I was technical, I just said I was hard on the machine.

I actually have ralphs system in hand and with three blues it is tight. Tighter than stock as far as I can tell. The delrin is thin and the damper extends past the head.

I think it will prove successful.

As far as my inputs go...since we've gone there. I can name a brand that ate it all up, didn't even blink at what I did to it...I never had a single problem with it.

The only reason I'm not flying it anymore is because I fell in love with the n7,and well its nice to share parts between machines.

[eobie]

I will also day that flight was a purpose flight. It was meant to stress the machine to prove that it is possible to bend the shaft in flight after being told it was impossible.

Its not indicative of my flight routine. The fact is I like power loops, I like the noise.... I live for blade farts, lol. So I did a bunch of powerloops and then would test for the bent shaft by doing some tic tocs.. 

[Greg Jackson]

I love the car analogies from Rob.  The point is, my C6 can handle a lot of abuse, because it was designed to.  But it still isn't indestructible and I could blow an engine.
 I guess the question is are there any benefits to being overly aggressive.  I enjoyed your video Ed as we all did but many of us fly the same moves and more, but it's about collective management. Hope I'm not offending, I'm saying this as positive as possible.  I think Matt, Rob and Kevin got the answers to you that we're needed from a setup standpoint so I won't butt in anymore, but i don't think adjusting your technique is a negative.  When I did drum competitions I had to change my technique even after getting my Master's in music and then my DMA. I'm very glad I did.  Just saying there is nothing wrong with change, we should always want to evolve. 
I apologize if I was out of line in anyone's eyes.  But I see this as a safety thing so I thought it should be said.

[eobie]

Its not out of line. There is a difference in lack of collective management and the intentional bashing I'm doing. Like I said... Its not my whole routine, its a maneuver that I like to do and if it can't handle just give me the word and I'll stop trying to fix this and go back to what I used to fly.. As far as safety, there is nothing that I am doing that would be considered unsafe.

I am beyond frustrated now and if the word is that this machine will never do what I want it to just say the word. I won't change what I enjoy to do to fall in line with what the machine can handle...

Let's use a car analogy... Let's say you like to go race but your tires keep breaking traction in the turns, do you get new tires or put up with the slower lap times.

[Matt Botos]

The machine can handle it without a problem. This has been proved over and over again. This is just a matter of misconfiguration.

Matt

[eobie]

Thanks Matt, then I will continue to work on my setup.. This was not what I was getting from some of the replies.

[Matt Botos]

This hobby does take a high level of mechanical ability. Please take what has been recommended and apply it to your rotor head and you will have success.

A few facts in closing -
- Blade farts may sound cool to you... but are very bad for the helicopter.
- Anyone can fly a helicopter and try to destroy it.
- ANY helicopter can be destroyed in flight with a skilled pilot.
- True skill is making a helicopter look like its being punished when it really is not


Matt