think your OWB is fixed with red threadlock? think again...

[istandalone]

today i did a few things to the hurricane 550 and went out to my spot. 40+ degree f with no wind. a gorgeous day to say the least. i go to spool up, and all of a sudden (while still on the ground, thank christ) the whole heli spun around in circles- just like the gyro was reversed but i know it's not, i haven't touched it. upon inspection i found nothing wrong. so, on a whim i switched my motor wires thinking they got mixed up in the repairs and the owb shaft was sticking (i didn't pay attention to what direction the blades were spinning). spool up, now just the motor spins, not the blades. stumped. then i remember the owb i fixed the day i put the heli together. after verifying that the motor was in fact spinning the correct way, i spooled up with my finger underneath the owb shaft (dumb, i know but the blades wouldn't spin for shit) and low and behold the shaft is spinning in the owb. so, to all of you whom have used red threadlock to fix this problem, you might want to go back and use something stronger. like jb weld. so, i've got to redo the fix i did 3 weeks ago and i can't fly today, and don't have time to fix it again and still get out to fly.:arggg::arggg::arggg::arggg::arggg::arggg:

so now, should i be going after gaui for another shaft and bearing, or readyheli? probly not readyheli because i know they have nothing to do with the problem, it's all gauis. i could scream. so now i'm going to go do this :smokin:, and maybe the gods will look down on me and i'll get it put back together in time to fly. thanks for listening to my rant, i feel much better now. well i will soon, cough cough :smokin:

[Happy|Harry]

why on earth would you use red threadlock on a one way bearing?

guys i strongly advise everyone to upgrade to the 20T one way bearing as it is much more meaty and has much less chance of splitting like the original 19T one :cool:

phil

[istandalone]

because there was and still is a known problem with them. some of the time said bearing would slide right out of the pinion gear, i had to tap mine a bit but it was loose and obviously would spin. it was said that if you didn't have green threadlock, red would do. i guess not.

[lightbulbjim]

I have a small bottle of Loctite 609 that I use for this kind of stuff. Bought it when my T-Rex swash fell apart. If my H550 one way bearing ever needs gluing this is what I'll use.

Datasheet here if you're interested: http://tds.loctite.com/tds5/docs/609-EN.PDF

[istandalone]

is 609 the green stuff? i removed the bearing and shaft again, and pressed the bearing out of the gear. i scuffed up the inside of the pinion and the outer face of the bearing with a steel brush, let it dry for an hour and tested it. i got about 5' off the ground and it let go. thank god for practicing autos on the sim! it still landed hard, but the cheesy gaui landing gear survived.

[Happy|Harry]

have you checked to see if the pinion is split? cause that was the problem most were having with the one way

phil

[istandalone]

i just checked that, and it doesn't seem it is. if it's cracked it's very slight. i also just ordered the 20t owb and gear anyhow, so hopefully that will be more robust. have you had any issues what so ever with the 20t?

[Pinecone]

The cracks are VERY hard to see.

But I would bet it is cracked.

609 is green, but not ANY green stuff. It is high strength product specifcally made of locking non-threaded cylindrical assemblies.

[WhirlingBladesOfDeath]

I saw Pincone's question in another thread, but no answer yet.

Do you have to change the main gear to use the 20T OWB? Seems like you should, but I can't find any info on it.

Thanks,
Jason

[lightbulbjim]

609 is green, but not ANY green stuff. It is high strength product specifcally made of locking non-threaded cylindrical assemblies.

It also needs 24 hours to cure. After only an hour it won't hold at all. Check the curing strength curves on the data sheet.

[istandalone]

Do you have to change the main gear to use the 20T OWB?

how about this? won't the mesh be different with a bigger gear? i didn't think of that before i ordered.

[Happy|Harry]

edited as i shouldn't be posting so late while a little tipsy lol :D

see post 15 for correct data

phil

[istandalone]

hey thanks! i didn't figure going up one tooth count was going to make a huge difference anyhow, but still i wondered.

[BL]

no the 20T one way fits with the standard 61T secondary gear cause there is only 0.2mm of a difference in diameter between the 19 and 20T one way, so the mesh between the one way and the secondary gear is only 0.1mm of a difference from the 19T to the 20T :)

pics to show the size difference
19T OWB

http://freespace.virgin.net/catherine.smith1/Hurricane550HV/19T_OWB.jpg


20T OWB

http://freespace.virgin.net/catherine.smith1/Hurricane550HV/20T_OWB.jpg

hope this helps
phil

Thanks for the info Phil,

I will be interested to know if you can measure it by using the tip of the caliper to slot in between the tooth. This will measure the actual diameter.

The reason is the teeth angle that you measure may have slight different between 19T and 20T.

[Happy|Harry]

BL you are correct that the angles were different, as the 19T isn't symmetrical like the 20T (i would have noticed this if i wasn't taking the pics and posting them so late in a long day lol) but there is an easy way to calculate the outer diameter and pitch diameter of any metric gear, the formula is

Mod x (tooth count+2) = OD

Mod x tooth count = PD

so for these gears
19T
0.8 x (19+2) = 16.8mm OD
0.8 x 19 = 15.2mm PD

20T
0.8 x (20+2) = 17.6mm OD
0.8 x 20 = 16mm PD

so there is a 0.4mm difference between the 19T and 20T pinions where they interface with the 61T secondary gear. but the 20T OWB assembles very easily and i've seen no extra wear since switching over so it can't make that much difference :)

phil

[istandalone]

my 20t should be here tomorrow, and my bottle of loctite 609 sits in front of me. we'll see tomorrow if the 609 holds up in the 19t- i'll fasten the gear again tonight and test it out before i install the 20t.