Swash Cam Video : 800e Trekker One Way Bearing Failure

[nu66ie]

Was flying today and decide to make a "Swash Cam" video. Half way into the flight, the OWB failed forcing me into autorotation from about 100 feet up.

This is the second time the OWB has slipped on this heli in about 10 flights. I did replace the OWB shaft after the first time. The bolts on the underside will not stay tight. First time I used blue loctite, the second time I used red loctite. The threads in the case seem very minimal. When the bolts are removed, most of the bolt threads are smooth, full of loctite. Looks like a shoulder bolt.

I did notice small black dots near two of the bolts where the lube was starting to leak.

The bolt on two of the holes actually pull out without turning. I aligned, then scored them with the case with an hobby knife. The score marks are lined up but the bolts were not tight. Managed to autorotate it down safely both times.

Finally pulled the OWB out of my 700e and installed it. Flew it a couple more flights with the same settings and all was fine. I was experimenting with the pitch pump in the Vbar settings and did bog the motor a few times on the double tap tictocs.

[hidaven]

Wow! Is this hub a redesign? can you use the hub off the 700? i dont trust this piece of garbage as I had 2 with the same problem.

[nu66ie]

The OWB is the same on the 700e and 800e.

Look at the treads on the 800e OWB case, use a straight pin to feel the threads on the six holes that run into the underside of the case. They are hardly detectable. The threads on the one out of my 700e are well defined. This tells me that this is pretty much a quality control issue. Agreed?

It does suck that these birds are at risk from poor quality control on such an important part of the heli.

[JustinS]

At least you got it down safe, have you seen the new KDE owb hub?

[HeliGriff]

Originally Posted by nu66ie

The OWB is the same on the 700e and 800e.

Look at the treads on the 800e OWB case, use a straight pin to feel the threads on the six holes that run into the underside of the case. They are hardly detectable. The threads on the one out of my 700e are well defined. This tells me that this is pretty much a quality control issue. Agreed?

It does suck that these birds are at risk from poor quality control on such an important part of the heli.

If a suitable replacement/repair is found, please post it HERE!
Thanks!

[hidaven]

Don I agree 100%. Make sure you point that out to Tim at Align as I am sending him a link to this thread. I had my orig. and my replacement with the same smooth holes. I also thought the the threads were not coarse enough and was thinking of re tapping but decided this was not my responsibility. My guess is that the replacement parts unless re designed, will all suffer the same fate. I would be VERY hesitant to use a replacement hub unless it was re designed.

Originally Posted by nu66ie

The OWB is the same on the 700e and 800e.

Look at the treads on the 800e OWB case, use a straight pin to feel the threads on the six holes that run into the underside of the case. They are hardly detectable. The threads on the one out of my 700e are well defined. This tells me that this is pretty much a quality control issue. Agreed?

It does suck that these birds are at risk from poor quality control on such an important part of the heli.

[hidaven]

Just sent Tim and Jeff who are great guys a link to the thread. At this point idonot want a replaced hub unless its redesigned as I think the manufacturing process is flawed and these are not just exceptions. I'm asking for a small credit or refund towards the KDE aftermarket hub if I can't get an improved coarser threaded version.

I suggest that ANYONE who purchases this 800 kit put a hex tool to the screws and make sure they are snug and holding. If this part fails in flight like the OP's did, you can loose control in a flash!

This is now SIX of these hubs that I know have failed. Lets hope Align jumps on this ASAP.

[nu66ie]

JustinS, your right, I got her down safe both times. But what about the next pilot who isn't proficient in doing autorotations? They could easily destroy the heli. I really wish Align will address this sometime sooner than later.

hidaven, thanks for bringing this to our attention and for your effort in contacting Align and showing them this thread.


This will probably be the best solution. It's $45 compared to to the $89 Align replacement. The bearing sprag itself is fine, it's just the treads in the underside of the case that are not suitable for holding the bearing in place under load.

Product description-
The One-Way Bearing Mount upgrade provides the ideal solution to the one-way bearing assembly failures common on the market with stock and aftermarket designs. By utilizing a one-piece, high-grade bearing-quality Stainless Steel 440C material construction, precision CNC-machined and secondary hardened to HRC60 rating; the new design provides a robust and failure-free setup for your 700- and 800-class helicopters. No more chance for slipping or failure of the one-way bearing assembly, there are no pressed-in sleeves or bearing-retaining compounds needed. In addition, due to the Stainless Steel construction of the upgrade, the risk of stripping threads for multiple gear chances and maintenance when tightening all hardware is greatly reduced.

Important: the upgrade is a direct bolt-in design for the TREX 700/800 series helicopters. To ensure proper operation, please review the Installation Diagram for assembly details and tips

Includes:
- One (1) TREX 700/800 Series Stainless Steel One-Way Bearing Mount
- Six (6) M2.5 x 0.45 x 8 mm Socket Head Cap Screws (Class 12.9 BP Alloy Steel)
- Six (6) M3 x 0.5 x 6 mm Button Head Socket Head Cap Screws (Class 12.9 BP Alloy Steel)
- One (1) Radial Ball Bearing 15 x 21 x 4 mm

Finish:
Glass-bead CNC satin, HRC60 Hardened

Weight:
38 g (design is FEA optimized for maximum strength and minimum weight)

[HeliGriff]

Originally Posted by nu66ie

JustinS, your right, I got her down safe both times. But what about the next pilot who isn't proficient in doing autorotations? They could easily destroy the heli. I really wish Align will address this sometime sooner than later.

hidaven, thanks for bringing this to our attention and for your effort in contacting Align and showing them this thread.


This will probably be the best solution. It's $45 compared to to the $89 Align replacement. The bearing sprag itself is fine, it's just the treads in the underside of the case that are not suitable for holding the bearing in place under load.

Product description-
The One-Way Bearing Mount upgrade provides the ideal solution to the one-way bearing assembly failures common on the market with stock and aftermarket designs. By utilizing a one-piece, high-grade bearing-quality Stainless Steel 440C material construction, precision CNC-machined and secondary hardened to HRC60 rating; the new design provides a robust and failure-free setup for your 700- and 800-class helicopters. No more chance for slipping or failure of the one-way bearing assembly, there are no pressed-in sleeves or bearing-retaining compounds needed. In addition, due to the Stainless Steel construction of the upgrade, the risk of stripping threads for multiple gear chances and maintenance when tightening all hardware is greatly reduced.

Important: the upgrade is a direct bolt-in design for the TREX 700/800 series helicopters. To ensure proper operation, please review the Installation Diagram for assembly details and tips

Includes:
- One (1) TREX 700/800 Series Stainless Steel One-Way Bearing Mount
- Six (6) M2.5 x 0.45 x 8 mm Socket Head Cap Screws (Class 12.9 BP Alloy Steel)
- Six (6) M3 x 0.5 x 6 mm Button Head Socket Head Cap Screws (Class 12.9 BP Alloy Steel)
- One (1) Radial Ball Bearing 15 x 21 x 4 mm

Finish:
Glass-bead CNC satin, HRC60 Hardened

Weight:
38 g (design is FEA optimized for maximum strength and minimum weight)

Is this KDE? Where do I buy it?

[nu66ie]

These are the two online stores that came up in a Google with it in stock.

KDE Direct
HeliDirect

ReadiHeli, Anything Heli, and AMain Hobbies don't show them in stock.

[HeliGriff]

Originally Posted by nu66ie

These are the two online stores that came up in a Google with it in stock.

KDE Direct
HeliDirect

ReadiHeli, Anything Heli, and AMain Hobbies don't show them in stock.

Super thanks! Getting one!

[cyphur01]

Mine went today too. Add me to the list

[nu66ie]

cyphur01,

Dang, sorry to hear that. Did you get it down safely?

Also, did you notice if any lube was flung onto the canopy inside? Or lube leaking out of the underside of the OWB case? How about the bolts that hold the case together, were they loose? Very minimal threads in the case?

Sorry for all the questions, I really want to let others know of some of the signs of pending OWB failure.

The OWB I took out of my 700e is starting to show the same signs after 20 flights. Small drops of lube near one of the bolts that is not holding.

I'm starting to wonder if these bearing cases were designed to handle the loads that the 800mm blades are putting on it.

I and a few others have ordered the KDE OWB mount, I hope that it solves the problem as the case is steel and not soft aluminum.

I appreciate your help...

[cyphur01]

I did get it down safely. Well almost. I was way out doing some big air and barely got it back to our place The tail got caught in some grass in the flare trying to stretch it and my tail drive gear stripped. I swear they make those out of bees wax. I can't wait until the new black gears come out. I opened the bearing up and it was very grimy in there with a ton of dust mixed n with the grease. I cleaned it all re greased it and seems tight again. I tightened down on the hub a little more than usual this time. We will see how long it lasts. I'll probably order the kde bc I'm not expecting this to last more than about 10 flights

[hidaven]

Just ordered the KDE upgrade. I'm a little confused, am I using all the bearings from the stock unit? Also, if you check out the diagram it looks like they want you to add loctited to the adial bearings inside that sleeve. Is that right? It then says its done at the factory? Lol. Check it out the bearings in question are number 3 in the diagram.


http://www.kdedirect.com/files/AT700...on_Diagram.PDF

Originally Posted by nu66ie

cyphur01,

Dang, sorry to hear that. Did you get it down safely?

Also, did you notice if any lube was flung onto the canopy inside? Or lube leaking out of the underside of the OWB case? How about the bolts that hold the case together, were they loose? Very minimal threads in the case?

Sorry for all the questions, I really want to let others know of some of the signs of pending OWB failure.

The OWB I took out of my 700e is starting to show the same signs after 20 flights. Small drops of lube near one of the bolts that is not holding.

I'm starting to wonder if these bearing cases were designed to handle the loads that the 800mm blades are putting on it.

I and a few others have ordered the KDE OWB mount, I hope that it solves the problem as the case is steel and not soft aluminum.

I appreciate your help...

[nu66ie]

You will use the existing end cap (6 on diagram) with existing radial bearing (3 on diagram), spacer (4 on diagram), one way bearing shaft (1 on diagram), and the existing bearing sprag (OWB) (5 on diagram).

The KDE kit includes new bolts for top and bottom sections (9 & 7 on diagram), the main mount with the radial bearing already installed (2 & 3 on diagram). Don't use any of the existing bolts.

If you have many flights on the existing OWB it is advisable to replace the radial bearing (3 on diagram), and the one way bearing shaft (1 on diagram), and even the main shaft if it is showing unusual wear.

Then use the bearing retainer on the new radial. It already has it from Align. (hopefully)

While your at it, you may want to get the new main gear for the 800e.

[Tek18x]

This was amazing! Looks great

[nu66ie]

Got the KDE OWB mount installed, hope this cures the slipping failures. The new mount is very heavy and the threads are deep. The case is machined well and is high quality. And most of all, I could actually tighten the bolts to the case cover.

[hidaven]

Don, was the slipping a result of the screws loosening on the stock OWB holder? I know you had to auto down, align is claiming that the slippage is not related to the bad bolts.....looks like the improvement with the KDE version is the better block and screw holes which is fine but the new block is still using all the stock align inners......

Also, did you put a little grease or did you use triflow on the OWB? I read people lean more towards ATF or other clutch lube.

[nu66ie]

It only makes sense. Screws tight, the OWB works fine. Screws pulled out, the OWB slips.

Here is how it was explained to me is.

When you pull a cork from a wine bottle, you cannot just pull it straight out, it must be twisted and pulled at the same time. That minuscule amount of movement where the OWB slides up and down on the OWB shaft is enough to allow slippage. This probably is happening more than you hear and eventually the OWB shaft and or OWB will fail.

Why do you think Align added the 18x22.7x0.7mm spacer in there? To stop the bearing from sliding up and down on the OWB shaft? Before they added that spacer, there were constant reports of OWB slippage issues. Now with the 800 spinning those giant blades, it seems that the 700e's soft aluminum OWB mount design cannot handle the loads placed on it. I took my original 800e OWB mount and tapped it out and put in 3mm bolts. I put a few flights on it while I was waiting on my KDE OWB case and it flew fine. (First picture below)

The KDE stainless steel OWB mount is as solid as it gets. If I get more than 20 flights out of it without the bolts pulling out and failing, wouldn't it be safe to say that there may be a problem with the 700e OWB's use in the 800e?

If the problem is not the bolts being pulled out of the OWB mount, did Align say what was causing the failures? If it is something we can prevent, it would be really nice to know. The metal sleeve in the autorotation gear contacts the bearing in the OWB case cover. Maybe the bearing is moving? Maybe the tolerances in the middle main bearing block could be the culprit? Or the jesus bolt? OWB shaft tolerances? It would be nice to know so we are not having to draw conclusions...

I do use a small amount of grease. I tried various greases and lubes and have settled on using a small amount of Lucas Red N Tacky. It doesn't break down and seems to give the most protection. The second photo below shows a spot of lube coming out of the bottom of the OWB. To me, this is a sign of imminent failure.On both occasions mine failed, these spots appeared several flights before failure. Also if you are seeing lube slung on the insides of the canopy right at the gear level, it's most likely lube being slung out of the loose OWB case cover, again, imminent failure.