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HelicopterHIROBOOther › Sceadu Tail Sloppy (would like to hear from the​Hirobo reps if possible)
03-12-2003 05:07 PM  14 years agoPost 1
Paul_Barsamian

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Glenview (North​Suburban Chicago)

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OK whats up with this skiddy tail? Finally got most of the machine sorted and I almost put it in last night because the tail went way sloppy on me. I bought what I thought was the upgraded complete tail kit with the grips, new hub, and dual bearing (no thrust bearing both are regular bearings).

The grips are sloppy, I can wiggle the tail blades laterally (ie the tips from a 90 degree angle to the drive shaft) at least 5 mm in each direction.

I have quadruple checked the instructions and have assembled it exactly as specified. In slow mo, it feels fine but if I piro or do anything fast moving this tail is way outta whack and just plain feels loose. Am using a good (tested separately) 401/9253 combo and NHP 90mm carbon blades.

Shaft is straight and everything is balanced. My raptor tail feels ten times as good as thing and I am not sure that should be the case, any ideas from the crowd what I might be doing wrong? Should there be this much mechanical slop in the tail???

Jeff G. any wiegh in???


I think cocaine would have been a cheaper habit...

Son, before you can soar with the eagles you have to learn to sh** with the chickens

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03-12-2003 05:21 PM  14 years agoPost 2
rockcrawler

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Covington Wa

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I put a r60 tail on mine and was done with it.
I had the same problem. They say it workes fine but I just didnt like
it so I switched. I would recomend the frea tail hub assembly
its rock solid and bolts right on.

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03-12-2003 06:18 PM  14 years agoPost 3
kokemon

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Little Rock AFB

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03-12-2003 06:25 PM  14 years agoPost 4
vetrider

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Daleville, AL​(Ft.Rucker)

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My Sceadu, another one sitting in my shop that's my buddies, and the 4 other one's flying in the Ft. Campbell, KY area all have the same design and grip movement. If you use 93mm blades, or better, the tail will lock-on with the gy401/9253.
When the TR is doing its thing at flight rpm it doesn't flex as much due to the bearings being loaded as designed.
I am a rep for Hirobo MRC-Altech but there are others much more experianced than me.

Nolan

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03-12-2003 07:54 PM  14 years agoPost 5
squirrel

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South Whitley, IN

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With the Freya blades and the gyro linkage set up correctly the 401 and the "wobbley tail" is fine.

squirrel

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03-12-2003 09:46 PM  14 years agoPost 6
Granpa

rrNovice

Sydney

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Wobbly Tail

Here's a trick I use. Hold the two halves of the tail blade holders together and you can probably see light through the gap. A few swipes on a peice of 1200 wet and dry paper on a flat surface will remove the tiny mould flash and ensure the grips hold the bearings tightly.

Don't forget that you're checking the radial play of the bearings with a huge moment, and any play will be exaggerated! (Around 20 - 25 times!?)

Then, I am curious to know how you think you can tell this in flight when everything is loaded up - but I'm just an infant in this game!

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03-12-2003 09:56 PM  14 years agoPost 7
Paul_Barsamian

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Glenview (North​Suburban Chicago)

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Thanks to all who weighed in. I think I am addressing two different issues based on your comments and what I experienced in flight.

The mechanical slop I am asking about from the static on the ground check I described seems to be normal, if not purposeful, (correct me if I am wrong).

My in flight experience may be attributed to the gyro setup, My gain on the 401 was set at 48 % when the tail 'let go' at the end of the pirouette I was trying. The tail was also kicking out about 45-60 degrees if I punched the little bird, similar reaction on quick descent. In general the tail felt quite loose even in slow flight, although in that mode it was not terrible.

What are you all using for gain on your 401/skiddies?

Son, before you can soar with the eagles you have to learn to sh** with the chickens

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03-12-2003 10:54 PM  14 years agoPost 8
rockcrawler

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Covington Wa

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70% and up...
120% - 130% atv gain on rudder chan.
no revo mixes.

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03-12-2003 10:59 PM  14 years agoPost 9
fitenfyr

rrProfessor

Port Orchard,​Washington

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Gain...

Put the bigger Freya tail blades on and put your gain to at least 55%.
If you are running it at 48% you are not in HH mode and running a pretty high rate gain. Assuming you are using a Futaba radio, but I would think JR would be similar.
Sounds like you just need to up your gain some. The grip issue is like Nolan said a "normal" thing.
I have one of the best holding tails in my neck of the woods on the Sceadu and that is all I have done with the 401/9253 combo.

Jason Stiffey
Fly Fast....Live Slow...

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03-13-2003 02:16 AM  14 years agoPost 10
squirrel

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South Whitley, IN

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If you are interested I can measure the distance from the servo axis to the ball. This is VERY important to a proper gyro set up.

squirrel

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03-13-2003 03:30 PM  14 years agoPost 11
Paul_Barsamian

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Glenview (North​Suburban Chicago)

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Update:

I reset the carbon rod length got the servo recentered and cranked the gain up, it seems to have fixed the problem. The stock hub kit was destroyed when one of the nuts let loose during spin up a while back so I bought the kit with a new hub, grips, bearings etc. The servo arm has 18mm between the center of the screw and the center of the ball link.

Do I really need the thrust bearing instead of the two stock ones? Do I need to go get a pair of them? Both setups seem to wiggle about the same, how much value do the thrust bearings really add?

I found the package, it was an "SE" Hirobo "Option" part. I don't remember the number off hand, I think it started with a 402.

Son, before you can soar with the eagles you have to learn to sh** with the chickens

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03-13-2003 03:39 PM  14 years agoPost 12
Paul_Barsamian

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Glenview (North​Suburban Chicago)

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BTW

I am running a 9CHP with the skiddy. I now have the gain set for 100% in normal mode and 90% in AVCS mode. Tail feels much tighter prolly too tight since I like to piro fast. I think I just had the gain scandelously low. On the rappy, it wags with anything more than like 48% and 40% held it perfectly but also piro'ed perfectly. Since I was using the same gyro/servo, blades, and carbon pushrod kit I foolishly thought that the gain should be set similarly.

Son, before you can soar with the eagles you have to learn to sh** with the chickens

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03-13-2003 04:07 PM  14 years agoPost 13
MRC-Hirobo

rrKey Veteran

Edison, NJ

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Sorry to chime in so late on this one.

There is no difference other than bearing wear between the RG rigid dual BB setup and the Standard Sceadu set up. On the RG the duall BB can actually wear out faster. That is why Hirobo used went to a bb/thrust assembly. That "slop" goes away when spun up.

Good to hear you got it working.

Jeff G

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03-13-2003 05:57 PM  14 years agoPost 14
fitenfyr

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Port Orchard,​Washington

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Hmmm...

Well if you have your gain up that high right now. I bet you could move the ball in a tad on the horn and lower that gain for better Piro rates.
I think I have mine at like 14mm on the large servo wheel.

Jason Stiffey
Fly Fast....Live Slow...

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03-13-2003 06:08 PM  14 years agoPost 15
vetrider

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Daleville, AL​(Ft.Rucker)

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I've never had to run my gain past 65% in HH and 50% in normal on the Futaba 9C and the GY401/9253 combo.

I'm all the way out on the 4 star futaba arm that comes with the 9253. I use a carbon rod to the TR and have the link ball all the way out on the TR arm as well.

I would advise that you not run above 70% gain as it'll cause the life of the servo to diminish greatly.

Nolan

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04-11-2003 05:22 PM  14 years agoPost 16
Paul_Barsamian

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Glenview (North​Suburban Chicago)

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OK I figgered it out.

I remembered a problem I had with another heli while back and decided to check the tail blades for smooth pitch movement, "under load". I pulled the tail hub with grips/blades and all completely off and checked by pulling on the two grips away from each other and the center of the hub to simulate the load of centripital force while they are spinning. Then I tried to twist the grips while exerting this force. I felt a grinding in one of the grips while doing this, even though with no "load" it felt silky smooth.

AHA!!!

I disassembled the grip and the two radial bearings I was using FELL APART IN MY HAND, metal pieces, balls everywhere.

Needless to say I replace the whole bearing set on the tail, did the thrust plus radial bearing combo as in the stock tail. Assembled and flew.

The tail is dead nuts solid at 40% gain on the gyro now.

TEST YOUR PROBLEMS UNDER LOAD!

Son, before you can soar with the eagles you have to learn to sh** with the chickens

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04-25-2003 02:52 PM  14 years agoPost 17
Paul_Barsamian

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Glenview (North​Suburban Chicago)

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More flying updates.

Tail was much better after the bearing fiasco. I am up to 45% gain and the piro rate is scary, (but I like it). I was having an issue with a periodic waggle in the hover though. Wasn't consistant enough to be purely mechanical or so I thought.

One thing I noticed, I had the gyro on this model all the way in the front like most of the recommendations on this forum and RCU. Problem is even though the heli is smooth in flight, that front lip seems to be the highest vibration point on the heli.

I tested different spots by having her at idle and just putting my finger on different flat spots on the heli to see which felt the worst. The front lip was by far the worst, the next 'step' up was the plastic going over one of the servos, better but still vibes, finally I tested the spot right over the tail boom clamp in the back where the manufacturer recommends. That had nearly no vibration. Since I didn't have the mounting plate, I just make one from CF stock laying around and secured it to that spot.

Moved the gyro and haven't had an issue since.

Son, before you can soar with the eagles you have to learn to sh** with the chickens

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HelicopterHIROBOOther › Sceadu Tail Sloppy (would like to hear from the​Hirobo reps if possible)
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