DAMMIT! Stuffed the Hurri... 1-way bearing failed,

[ukgroucho]

Went out for some flights this afternoon. First flight I lifted off, did a couple of piros and moved off to my right (into the wind). Heli was at maybe 15 feet and I turn downwind and it just lost power. Too low to try to auto and heding downwind so it landed very hard in mefium length grass.

Not too much damage from a cost perspective - tail blade, boom, LG legs. Not sure about shafts in the tail and head, will need to check. I could not figure out what happened but fiddling with the wreck just now I realise that the one way bearing has died. Obviously it let loose in flight :arggg:

Anyone else had these fail so suddenly?

[skydude]

My sincerest condolences.

Are you assuming the owb went out in flight because it would not auto in?

Wait a minute, you say you did not try to auto. Why do you think the owb went out in flight?

--

[skydude]

If the owb goes out in flight wouldn't the motor rev real high suddenly?

==

[odieser]

perhaps the pinion came loose It has happened to me.
Mark

[bugdozer]

I have heard of two reasons for one-way failure. One is the gear spins on the one-way bearing as it may not have been glued properly. While building my Huri I went ahead and tapped the one-way out of the gear and re-glued it with Loctite 609. The other problem is the gear on the one-way cracks. There is a 20T one-way upgrade that is a direct replacement that should correct for the failures. I have one but have not gotten around to putting it in.

[bpd964]

Just found out about the one-way-gear issue myself........

Mine cracked as a result of the crash, not the reason for it..

[ukgroucho]

I have not pulled the one-way out yet but

- complete loss of power in flight. I was LOW and just turned downwind with very little forward speed so even attempting an auto would have been hard... I pretty much killed what HS I had during the turn as I applied extra pitch to accomodate for turning downwind (10 - 15mph wind).

- I can now spin the motor both ways freely without the head trying to turn.

- Hard to tell if the motor tried to over-rev... it would only have been VERY brief anyway as I use a Kontronik Jazz in governor mode.

I'll post when I have dissected the one way.

[Mikej]

I have ordered a new 20 tooth OWB - can someone point me towards the instructions on how to replace it please - I've done a search bit can't find them.

Ta,
Mike.

[odieser]

http://www.helifreak.com/showthread.php?t=55030&highlight=owb
mark

[Mikej]

http://www.helifreak.com/showthread.php?t=55030&highlight=owb
mark

Thanks Mark - that's what I was looking for :thumbup:

[mjdee14]

Not sure what 4 bolts they are talking about in that thread, but to remove mine I first removed the bolt on the bottom main shaft (head shaft), slid shaft up and removed gear.

Loosened two allen screws on first gear ( one mating with pinion) then drove OWB shaft out through the bottom....installed new OWB and reversed order....about a 15 minute job.

[ukgroucho]

So I finally got around to the rebuild and found that the one-way does not seem to have failed.

The primary drive shaft had 'slipped' and dropped a few mm. One of the grub screws that holds the primary gear on was gone and the other was loose. The aluminium on the primary gear carrier seems very soft to me... seems that the grub screws strip very easily.
Maybe I'm heavy handed but for a component which transfers all of the power from the motor to the drive train these seems pretty soft. I've had another one of these fail also... as I said, maybe it's me but I know I now need to take much more care with tis component.

[mjdee14]

UK...what motor are you running? maybe the power added to the problem.....

I noticed on my short OWB shaft it has a flat on one side....the new improved longer shaft has two dimples for the grub screws..

i guess this is one of those "Tweaking" items that need to be checked every so often.

The problem with this heli and electrics in general is they are "so darn easy to use" i just leave it in my trunk....grab a quick flight whenever and wherever and never really tinker with it unless I have to...in this case it would be too late....

[ukgroucho]

z30 800Kv on 10S LiPo... yes it has LOTS of power.

[badriM]

For me this one way gear is a real problem. At this day, i have 100 fly with twoo hury 550 (one plastic and the other full carboon).
I have change this damned gear three times. I try to sold it with somme red loctite, no real effect. The gear always slide. I run on the first with the stock engine and for the second with a Zpower 20 980t. No realy the power of my z30 on my raptor.
Why Gaui don't create an other stock one way gear than can run more than 30 fly ? How many hurry must crash before they can make a new serious parts ?
Another facts is that hely Has suffered many modifications after his first commercialisation (main gear, tail, swash plate...). It is like they don't try it before it cames on market.
I have twoo Raptor 550 E and in 150 fly i never change any parts ??? But for Thunder Tiger hely, I never see one modification after it cames in the store. It is the clear evidence that they test it in fly before sell it.

[ukgroucho]

I hear what you are saying badriM... I really like the Hurricane... GREAT size / weight, flies really nicely etc... BUT I seem to break things in the drive train all the time, and this causes crashes and costs BIG.

I'm sure that some of this is "me".. but right now it is starting to feel like it is an uphill activity.

[michael88997]

that might be a hit and miss thing with the one way because i have had the same one way for almost 50 or 60 flights and its still goin strong

[skydude]

.
Why Gaui don't create an other stock one way gear than can run more than 30 fly ? How many hurry must crash before they can make a new serious parts ?
Another facts is that hely Has suffered many modifications after his first commercialisation (main gear, tail, swash plate...). It is like they don't try it before it cames on market.


Even full size stuff in the aerospace world suffers from this phenomenon. And the automobile industry. (and of course every other industry). It comes down to who is in charge of the departments up and down the design to specify/procurement chain of whatever component/system.

Good systems really stand out. That is why Toyota is taking over, and I am not completely happy with what they are putting out. (Sloppy transmission, doesn't snap start like the nissan did with 160,000 miles and this toyota is brand new, braking doesn't compare. (bought the toy truck cuz it has more room for my bud - Jeb dog. It's really his truck))

--

[badriM]

I can't agree, if you compare an hely and a car. Can you imagine how many parts you have in a car ? You can run with it 10 years on road in polution, cold time like snow and rain . Our hely's are finaly very simple only 100 parts to test in fly before put him on market.
If the huri 550 have been test Intensely it is impossible they can see they have problems in transmision ( main gear, one way gear...).
In fact they see the different failure but only AFTER sell it exept the one way gear who always make problems.

I love my twoo Hury, they fly very well and the spares part are very low cost. One of them is now and Agusta 109 as you can see it at this adress :

http://www.helifreak.com/showthread.php?t=65535

But this unsolved problem with transmition makes me completely mad. If he exist somewere and custom parts of this damned main gear even for 100 $, I buy immediately twoo of them, just to have peace and could fly without have fear that he could broke in fly and let me without power.

[mjdee14]

I'm going to have to agree with badriM on this one...

i think we are all forgetting the "stipped" gears we had before the OK gears.....you can't tell me anyone at the factory put this heli through it's paces using one of the assembly line models.

Anyone can make a prototype with the best materials, show proof of concept, then send the specs to the factory only to have them "screw" it up in manufacture.

There was no reason to have crummy gears from the begiining...there was no reason to have the swashplates separating, or the OWB coming apart.....OWB have been used in helis for a long time.....and we don't hear of the problems we have had...

Now I'm sure price has something to do with it...and I have to applaud Gaui and it's distributors for taking quick action to fix the problems.....

But I think if you gave this heli to about 10 good modelers and let them "ring it out" you could have identified many of the inherent problems before production....

"We" should not have to CRASH our helis to help them get the bugs worked out....


How long would Toyota be in buisiness if everyone was crashing their cars ?

[Mikej]

But, to extend the analogy, if people bought Toyotas and then put in a motor that was twice as powerful as the original motor then they would have problems. Most of the problems people had with stripping gears were with much more powerful motors than standard. Gaui's recommendation is "motor ~ 800 - 1200KV Battery 11.1V 2200mah 25C Li - Po in series (22.2V)"

What always worried me more was the self-tappers that were only holding on by a couple of threads.

[mjdee14]

What always worried me more was the self-tappers that were only holding on by a couple of threads.

Mike your right.....I forgot about those......anyone with 1/2 a brain would not have used those screws.....

I think it's just the factory either not following specs....or those screws were a lot cheaper than the proper length....

AS far as the motor....I think it ws Gaui themselves that sold a more powerful motor for the heli.....

I love this heli....and if you look at the Trex thread....they are not without their own set of problems....maybe just not as many.

[Mikej]

I love this heli....
Agreed :YeaBaby::YeaBaby:


....and if you look at the Trex thread....they are not without their own set of problems....maybe just not as many.
A couple of friends have bought Trex 500s (spending a LOT more than me in the process) and are unfortunately having problems still

[badriM]

Just 2 thinks, I have the same problem with my 2 hury. One with the stock motor and the other with a Zpower 20 980 turn/v. For the first no excuse for the factory and for the second remember that is Gaui imself that sell the first big engine like an upgrade on this Hely.
Why propose in your catalog a big engine when with the stock your main gear and 1 way gear cames like butter in hot water ? I think it is not serius to imagine that the consumer have to make the crash test insted of the factory.

[mysticmead]

it's also important to remember, Gaui did correct the links and screws.. they also did correct the soft gears.. the OWB they came out with the 8mm 20T to make it stronger. so it's not like they aren't fixing problems..

while it would have been nice to not have those problems to begin with. it all comes down the same thing that other companies do.. Microsoft is the worst.. push a product out and fix it later. it's the way most businesses work now. The computer hardware industry is no different. they skip the quality control checks in order to reduce production costs. this is why you can have bad parts out of the box.


Other heli manufactures have design problems, they make changes AFTER production has started.. Align, and SJM are 2 that I know of.. they all fix problems that we feel should have been found before production started. but in this industry, being the first to market can make or break a company. It just sucks for the consumer.