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Old Apr 27, 2008, 03:49 PM
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Portchester Nr Portsmouth, Hampshire UK
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Futaba GY401 Gyro's/ Swift 4S

It has taken me 4 months to sort out what was I believe to be an intermittent HH GY401 fault (I first noted in October 07,which I spent 3 months trying to fix mechanicaly assuming rear end wear, replacing blades,bearings gearbox,tail slider)with 2 GY401's.

The first gyro I crashed the swift from 50 feet losing orientation but semi auto's such that only damage was 1 broken main blade and a blade grip and a u/cart.
The 2nd most recent GY401 I tried was from a mini Titan that was as far as I was concerned fine and "locked" and odd that it was not reliably going into HH and if doing so HH would be out of sku of gradually creeping this airframe had crashed 1x - damage skin front broke off.

The 3rd GY401 I fitted over the weekend locked as ALL heli's have been till this problem occured.
On happy note a just finished Swift with a FUNKEY squirrel body took about 5 mins to sort it's GY401 so simply.

IN ALL CASES I FIT THE FUTABA SUPPLIED FOAM and allow plenty of side space and NO tension on gyro leads.

Are GY401's this delicate such that LOW/MED crashes can cause problems OR are there some subtlties in manufacture that make them not consistent.

As historically I used to be a component engineer, solid state device are pretty tough.

Is what I have gone thru rare or not for the GY401 or gyro's in particular.

The downside of the trouble I have had is the lack of confidence I have had with the Swift being FAR more happy flying my mini titan or 450X believing the fault the Swift in general NOT the gyro.
Heritic
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Old Apr 27, 2008, 04:16 PM
Conformity Kill's
Mission Viejo, CA
Joined Nov 2005
2,796 Posts
What is the problem, Drift, wag, blow outs....?

the only thime I have a 401 do anything but hold solid it when the headspeed drops under a load and there's not enough power for the tail to hold... or flying fast backwards in very stong wind (20+mph).

I have 401's in a Swift (6S), Raptor 30, Raptor 50, they all hold very well..

geneween
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Old Apr 27, 2008, 05:26 PM
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West Chester, Ohio
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Heritic, have you considered that maybe it's the tail servo or some other culprit seeing that three, seperate and perfectly good gyro's have put you back to the same point? I've got 401's in several Trex's of which it's performance is limited to the servo I match it with. Also, like geneween asked, what exactly is the problems your seeing?
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Old Apr 27, 2008, 05:39 PM
Our Daddy and Heli Junkie
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The 401 is anything but delicate.

I hate to say it but it has to be something in your setups. You are having way to much trouble to often with a solid proven product.

Do copy the setup from one heli to another? I hardly have to trim at all normally.

I have used diff tape, other servos and diff radios all with great luck.

There has to be something going on here somewhere.

FB
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Old Apr 27, 2008, 06:45 PM
mad heli scientist
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United States, OK, Oklahoma City
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4S is the lower voltage limit to fly a heli this size, so what I know tells me- I could be wrong here but I don't think so. The motor kv must be high enough (Fred probably knows exactly what this value range is) and you probably have about 2 choices for the right pinion gear tooth count. I've hovered my Swift at 1300rpm headspeed, but it's not easy. 1500 is what I would call the minimum to spin all the feathers fast enough to give you a reasonable degree of controllability- head and tail.

If you know all else is good and still having trouble, tach your headspeed.
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Old Apr 27, 2008, 07:52 PM
That'll hold until ...
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Hampton Roads Va.
Joined Oct 2004
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I have to agree, that it is more likely in the setup than 3 bad gy401s. My Swift is used and running 9S A123. It came with a GY401 that had been knocked off a Trex450 by the flybar and a large chunk of case knocked out. It still works fine.

Most all of my GY401s have tried to stabilize the tail while I tilled dirt with the mains.

Steve
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Old Apr 27, 2008, 08:57 PM
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I have flown the Swift with a 750 HS. Felt like a FP heli but the tail was solid.

My 4s setup is the 550+ with 95% on high gov (not a CCHV) with a 9t pinion. HS was 2000 with FG 520 blades.

The same heli on 4s emolis held fine with hitec 5345 on the tail.

FB
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Old Apr 28, 2008, 07:49 AM
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Portchester Nr Portsmouth, Hampshire UK
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On the face of it it does seem I have ben setting up wrong/headspeed low, BUT as I said my NEW 4S swift with a 600+ 11 pinion and 70% on ESC = 1600 headspeed on my tacho (not the chopper kind, but placed on ground and read at initial hover)took a few mins to sort AS ALL OTHER OF MY HELLI'S with the GY401 and has now had 5 off 15 minute "locked in " flight actually too locked in for a "cartoony" scale heli.
Heritic
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Last edited by Heritic; Apr 28, 2008 at 03:13 PM.
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Old Apr 28, 2008, 07:50 AM
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[QUOTE=swatson144]I have to agree, that it is more likely in the setup than 3 bad gy401s.
Maybe 2 as this latter one ok.
Heritic
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Old Apr 28, 2008, 07:55 AM
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If you know all else is good and still having trouble, tach your headspeed.

It has been 1700 in idle 1 1800 in idle 2 the kick/drift was worse at the higher headspeed.
Heritic
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Old Apr 28, 2008, 07:58 AM
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Portchester Nr Portsmouth, Hampshire UK
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Anyway, thanks for the comments regarding the tough GY401.

Thanks for ALL help REALLY appreciated and if no further problems then fault gone, I do accept I could be the fault but as I said above only had a problem with this Swift.
Cheers
Heritic
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Old Apr 28, 2008, 08:20 AM
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We do want to get the bottom of the problem Heritic, really.

You are trying to adjust HS though with %, not gearing and want long flights from a basic setup even 1 with a scale fuse.

Bump the % up to 90-100% and drop the pinion to 9t.

How much are you putting back into the packs?

FB
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Old Apr 28, 2008, 09:47 AM
Conformity Kill's
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please take a picture of where everything is placed on your heli...anytime I read the word kick... I think static or RF noise...or if you can get a video of it that would be perfect. What ESC are you using? and What Radio setup.


gene
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Old Apr 28, 2008, 03:42 PM
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[QUOTE=geneween]What is the problem, Drift, wag, blow outs....?

In HH drift /wagg.
Note when landing the gyro was always blinking once landed (sticks not being held).
Tripple switching back and forth end was always required to lock the gyro led.
Heritic
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Old Apr 28, 2008, 04:03 PM
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Quote:
Originally Posted by Gadget01
4S is the lower voltage limit to fly a heli this size, so what I know tells me- I could be wrong here but I don't think so. The motor kv must be high enough (Fred probably knows exactly what this value range is) and you probably have about 2 choices for the right pinion gear tooth count. I've hovered my Swift at 1300rpm headspeed, but it's not easy. 1500 is what I would call the minimum to spin all the feathers fast enough to give you a reasonable degree of controllability- head and tail.

The first motor had a job to make 1500 head speed but the tail locked fine.
Ash Davis of T-Rex tuning flew my Swift for it's first flight.
[I]
If you know all else is good and still having trouble, tach your headspeed.
1700+
Heritic
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