Tales of my tail (long post)

[EKron]

Sometimes I guess, the quest to improve and make things better isn't always a straight progression. Let's look at my last attempts as an example.

Several months ago, I purchased some CNC tail rotor grips with thrust bearings, Gaui part # G-204830. I was waiting for a crash to replace the ones I'd been using that came with my used 425. The opportunity finally came up so I gave them a shot along with a new output shaft, pitch slider and bearings. On the bench, everything was silky smooth and it looked good.



However, when I went flying on Sunday, I had a slow wag. Gyro gain didn't do much and a local master hovered it and deduced it was a binding problem. Pulled the control rod off at the gyro side and when worked by hand, everything was still nice and smooth. Took the main blades off and spooled up just enough for things to spin and could barely budge the control rod either way - binding under load. Ugh!

Plan B - do something different. I ordered an X5 tail hub and grips assembly (G-208950) and slightly filed the pitch slider arms to expose a bit more brass bushing where they connect to the grips. So far, on the bench at least, it feels good but testing under power will be the true test.

Not much current info and writing about these old birds so maybe this will be helpful? First of all, the CNC grips & hub I bought were crap. Reading threads here back to the 2009 era, there were several iterations of these CNC grips and some initial design problems but the ones I got were supposedly "new". I did disassemble and grease them up before installing and they felt smooth so I didn't think much about it at the time. My opinion has since changed. - there's only one radial bearing in each side.

This pic shows the CNC grip bearings on the bottom, the X5 bearings in the middle and the grips that were on it at the top (also with only 1 radial per side). Notice the hubs all have different size shafts too. The CNC's were the smallest and whatever the old ones were bigger with a bolt instead of a nut and one whopping grub screw instead of two little ones.



Here's what the internals assembled look like


The superiority of the X5 stuff is pretty obvious. For $19 bucks, I'm going to order another set and not worry about the metal blingage.

So with the short boom and running 425's, am I running the right tail blades? The new X5 grips give me about 10mm more diameter than the CNC's or the old whatever ones. I'm using KBDD Extreme Edition 72.5mm's and if I'm reading my CC Ice 75 logs right, getting about 2900 rpm headspeed. (Gaui GM-504 1400kv 15/50/19/61 10.7:1)



Now a word about my new CNC tail pitch slider itself. Parts G-208369 for the X5, G-213650 for the X4/NX4 and G-204640 for the 425/550 all appear to be exactly the same part! Reading about all the problems and recall on the NX4 and some of the X5 guys also reporting failures, I'm just crossing my fingers here that the one I got (G-204640) is a good one? Time will tell, I guess?

Finally, with the stock pitch arm control lever, it looked like the ball on the slider was going to pop out. The previous owner must have fooled with this too since I got 3 others in the box of parts that came with it. One, I can't identify, the one that was on it has "600" molded into the plastic and there was what I assume another stock one? Taking my own spin on things, I am using a metal arm from a T-Rex 600 with a Delrin insert that seems to capture the ball on the slider much better throughout the range of travel. I'm using the pushrod conversion set with a straight CF rod from it to the arm. With the ball on the Align arm pointing up, it tucks the tail rod up close to the boom and is perfectly parallel.



Okay, I'll stop yakking now! Just wanted to share.

-- Elisabeth

[Jerrymac]

Most Hurri owners used to just run Align Trex 600 tail hub and grips to solve the tail issues, but many use the X5 ones now. The issues with the X4/5 pitch slider were supposedly due to the bushing being over tightened when pre-assembled by Gaui causing it to crack. If you are using the X5 pitch slider you might want to disassemble it and make sure the bushing wasn't over tightened and damaged. I think Jack from Empire Hobby notified the people on the X5 forums here about the issue.

[EKron]

We'll see how it goes this Sunday but I think my problems have been solved?

I am running the Gaui CNC tail case and the metal T-Rex 600 pitch arm. The new X5 grips are very nice and a half throttle test on the bench seems to indicate my binding problems have been solved.

As I noted above, Gaui has 3 part numbers for the CNC tail pitch slider but they all look exactly the same. My understanding of the failures was that it was a recent manufacturing problem? The one I'm using is listed with the 425/550 stuff under part number G-204540. It was in the older red and white packaging so I'm hoping it is older stock from a pre-problem batch? I'm sure I could heat it up and take it apart with a small adjustable wrench but I figure there's a good chance of wrecking it in the process. It was about $22 and I'd rather not screw it up. I'm still working on upright orientations so I shouldn't really be stressing it?

I've got one of these Tarot pitch slider bushing tools on the slow boat. When it comes in, I'll check my slider if I haven't crashed and bent it up already.



--Elisabeth

PS - Thanks for the feedback, Jerrymac. Your opinions are highly respected.

[sp00fman]

Nice read.

I jumped on the X5 tailgrips immediately because of the advice on this forum and to have the thrustbearings. I did try both hurri's with the stock 425 tail but am disappointed. It tends to lock up. The X5 grips are really nice, no mods needed at all.. I keep everything bone stock plastic on the tailcase and slider assembly. I dont really see a reason to improve anything there. Besideds the alloy Gaui parts seem so darn expensive. I would rather get more lipo's than bling it out. Then again, my heli is not dressed up as nicely as your flying art project


The X5 runs 520mm blades,l as do i, so i chose to go along with the bigger tailblades. I dont know if the tail->mains ratio is the same on the hurricane, but it seems to hold fine for now.
My 425 has X5 grips with the stock short gaui blades. Holds super solid. Best tail of my fleet.

[stark]

Elisabeth,

If everything is OK on the mechanical side and you still face problems, try tinkering with the electronic settings. Governor mode on the ESC and the gyro can interfere with each other since both are control loops controlling two parameters (headspeed vs tail) which which are not entirely independent. I would make sure ESC is in rate mode when setting up the gyro.

cheers,

[EKron]

Originally Posted by sp00fman

...your flying art project t.

Haha! If you only knew the half of it. So many facets to this hobby and why I love it. If you think this is bad, you should see my 450 with my latest as of yet unflown canopy.



Just wait until I get done with the Arizona desert in the summertime, NACA ducted and swiss-cheesed T-Rex 550 canopy for my 425!

Originally Posted by sp00fman

...My 425 has X5 grips with the stock short gaui blades. Holds super solid. Best tail of my fleet.

I've got 2 sets of the stock Gaui tail blades going with me for testing and I have a four arm rudder servo horn installed with two balls on it with one of the balls a hole closer to the center so I can quickly flip it. I've got a frame mounted Futaba 9254 tail servo and am using the tail rod adapter thingy with a homemade carbon pushrod. It is kind of a balancing act to adjust but I'm really going to work on getting it and the proper gain settings all sorted out tomorrow.

Originally Posted by stark

Elisabeth,

If everything is OK on the mechanical side and you still face problems, try tinkering with the electronic settings. Governor mode on the ESC and the gyro can interfere with each other since both are control loops controlling two parameters (headspeed vs tail) which which are not entirely independent. I would make sure ESC is in rate mode when setting up the gyro.

cheers,

Uh, I'm sure you meant to make sure the gyro was in rate mode and the ESC not in gov mode and yes, I've done it that way.

Haven't tried govenor mode yet but am running a TC of 78 flat in normal, 88.5 flat in IU 1 and 100 flat in IU2. Soft spool up at 50% in normal, flip to IU 1 before lift off and am cautiously venturing into IU2 while airborne and stabilized. Baby -4º pitch curve in normal, about -7º in IU1 (working up to it) and -12/12 in IU2 with 50/75/100 on top for all three. Have got ALE, ELE & PIT setup with DR/Expo on a switch at 85/-28 or 100/-15 and RUD on another switch at 100/-22 or 95/-38. Trying to find my comfort zone and experimenting all the time. Once I get this figured out, I'll probably put DR/Expo settings on my IU switch for triple rates without having to flip a bunch of switches. (Futaba 7C)

Spartan Quark on the tail, endpoints 100/100 in the TX but adjusted in the Quark software. Combination of high & low endpoint numbers in the software add up to being just over 200 as recommended. Quark software default of 50% expo set to zero so I can adjust it from the TX. Gyro gain set at the recommended 30 in the TX but plan to do the "crank it up until it wags" dialing in tomorrow now that I'm super confident the mechanical problems I was having are now solved. Fingers crossed anyway. Also have a Quark on my 450 that wags hard at 33 but is perfect at 27.

Dang! Just sat down for a quickie reply and rambled on once again. Sorry.

-- Elisabeth

[stark]

Originally Posted by EKron

Uh, I'm sure you meant to make sure the gyro was in rate mode and the ESC not in gov mode and yes, I've done it that way.

Ah yes, sorry. I meant don't use governor mode on the ESC while hunting down tail issues. Also, once the tail is trimmed in rate mode I just put it in holding mode and forget about it .

Originally Posted by EKron

Haven't tried govenor mode yet but am running a TC of 78 flat in normal, 88.5 flat in IU 1 and 100 flat in IU2. Soft spool up at 50% in normal, flip to IU 1 before lift off and am cautiously venturing into IU2 while airborne and stabilized. Baby -4º pitch curve in normal, about -7º in IU1 (working up to it) and -12/12 in IU2 with 50/75/100 on top for all three. Have got ALE, ELE & PIT setup with DR/Expo on a switch at 85/-28 or 100/-15 and RUD on another switch at 100/-22 or 95/-38. Trying to find my comfort zone and experimenting all the time. Once I get this figured out, I'll probably put DR/Expo settings on my IU switch for triple rates without having to flip a bunch of switches. (Futaba 7C)

You have a handful of settings . I just use 2 flight modes normal for lift up + landing and IU1 for flight/stunt, never use dual rates/expo.

cheers.

[blade_crasher]

Elisabeth:

Your Gaui is so nice looking, it's a work of art.

Your heli table with what look like router slots and round plastic skid holders. Is that something you made or bought? Any plans or info you can send. I'm old and don't drive a truck and am tired of doing stuff on the ground when getting ready to fly.

Also, tell me about the Quark software. I simply programmed my quark using the TX sticks. Not much to it, about 3 or 4 things to set. What does the SW provide that I might be missing on?

rick

Originally Posted by EKron

...

Spartan Quark on the tail, endpoints 100/100 in the TX but adjusted in the Quark software. Combination of high & low endpoint numbers in the software add up to being just over 200 as recommended. Quark software ...
-- Elisabeth

[stark]

Originally Posted by blade_crasher

Also, tell me about the Quark software. I simply programmed my quark using the TX sticks. Not much to it, about 3 or 4 things to set. What does the SW provide that I might be missing on?

Rick,

You can check out Finless' video on Spartan Link configuration software to see the extra settings available,
https://www.helifreak.com/showthread.php?t=47240

To use the software on PC you need the spartan flash link dongle.

Alternatively, you can use the Spartan datapod. You can do all that you can do with the flash link but without requiring the laptop in the field.

cheers,

[EKron]

Originally Posted by blade_crasher

Elisabeth:

Your Gaui is so nice looking, it's a work of art.

Your heli table with what look like router slots and round plastic skid holders. Is that something you made or bought? Any plans or info you can send. I'm old and don't drive a truck and am tired of doing stuff on the ground when getting ready to fly.

Also, tell me about the Quark software. I simply programmed my quark using the TX sticks. Not much to it, about 3 or 4 things to set. What does the SW provide that I might be missing on?

rick

Thank you for the compliments! Here is what the Quark software looks like:



In addition to the Spartan Flash Link, you also need the Spartan SLX Adapter. They bone you pretty good for these two cables but it does give you so much more flexibility and control. For quick connecting, I have permanently installed the SLX Adapter on both my Hurri 425 and funky 450. I have my Castle Link Quick Connect connector taped to the bottom of my SLX adapter.

450

On my Gaui


As far as the stand thing, it's just something my widdle bwain cooked up. Initially, I designed it with sliding PVC poles thinking the top section might actually lift up a foot or so and fly but subsequently learned this is heavily frowned upon for safety reasons. I do still use it for backyard testing and it has saved me a couple of crashes but I do use it only with a flat 0º pitch setting or take the main blades off. In addition to the skid restraints I also run a velcro strap through the frame. There's a $5 lazy susan bearing from Home Depot in the top part. The little metal thing with a slot in it is where the velcro strap that goes through the frame runs. I originally made this for my 450 but have since made a bolt on adapter for my 425 that also works for my X2 and Hurricane 255.





Here's a poor quality short clip examining some stop bounce on my 450. You get the idea...
[ame]http://youtu.be/cgbP4uXLTCU[/ame]

So, back on topic...

The X5 tail grips worked great and solved 95% of my problem. No more wag but there's still something sticking or binding as there's some hesitation then jumping on tail input. I'm heading to a local shop tomorrow that's actually a Gaui dealer to see if they can figure it out and maybe hook me up with Empire and some Team Gaui knowledge.

Only got to cautiously fly a pack and half yesterday on my 425 and one on my 450. It was really windy, my eyes were watering and my nose was running so I gave up.

Hopefully, I'll have some better insight after getting some help tomorrow.

-- Elisabeth