bbs428 Build

[Eric Page]

Really glad you're safe, brother. Hope it's not an expensive repair!

[bbs428]

I'm pretty sure Leading edge air foils used to rent out rotax tools. I don't know now that they sold out but I would think they still would.

Glad you got it down ok. Those hills with trees are worst to fly over than water to me. Haha

Thats good to know. If I need to, I'll get in touch with them after the holidays.

Thanks man!
Yeah, it was a "Stone the crow's" moment.
The vibration felt like I slipped a quarter into the vibro-bed, but training kicked in quick, so I just flew the plane...
was really hoping it wouldn't be into the tops of the trees and "News at 6...Local pilot goes for his own wild ride in Branson!"

[bbs428]

Really glad you're safe, brother. Hope it's not an expensive repair!

Thanks, I appreciate that! Agreed, but It's all expensive, lol.

[bbs428]

Update:

Was able to tear down the gearbox and look around. The thrust washer was gone (plastic in the oil tank) and the 29-tooth little drive gear next to the washer was galled up a bit. Everything else looked brand new.

Talked to Hal Stockman and he explained that when that plastic washer disintegrates or breaks up, the pre-load on the dogears (which is critical) drops and they start hammering on each other, hence the vibration. He has a fix that replaces that washer with one that is not plastic.
I love being Experimental!!
He made me an offer to look it all over, fix what was needed plus put in an oil sprayer that will extend the service life of the gearbox for a great price that I could not refuse, so I'm sending it to him tomorrow.
Hal is the best!

Not sure if it will be back in time to put some hours on it and go to Oshkosh. If not, there's always next year!

IMG_2717[1].jpg IMG_2718[1].jpg

[Geek]

That's awesome Brett. Kind of what you expected and now you'll be better than new. Glad that beautiful plane of yours is going to still be providing you all that fun. Even if you don't make Oshkosh it will be done right for sure.

Geek

[Jason Murphy]

Disregard, Looks like you have already talked to Hal

[bbs428]

Finished the gearbox today. It was actually enjoyable to be working in the shop again.
I ended up just getting the consumable parts and an assortment of shims from Hal because I was running out of time to make it to Oshkosh. I'll have him install the oil squirter next time it needs overhauled. I just followed the Rotax MMH pdf, and it was a pretty straight forward procedure.
Made my own tool to remove/ install the keepers (ring half's). As the gearbox had only 110 hrs., so the main bearings and clutch pack were left alone.

It's all ready to fire up but it's 95deg. outside in the shade so I'll do a low power/high power turn in the cool of the morning tomorrow. If that goes well, it's back on the trailer for the 1.5 hours trip to Bolivar for some flight testing. Need some time on the gearbox to go that far from my home base!
Then I'll make the call if we're going to Oshkosh or not.

Fingers crossed!


in the plane.jpg

[bbs428]

Well that went well, as in NOT

Bad shake on start-up. Shut down and eventually found #4 had no compression. Shot some compressed air into the cylinder and "whoosh!" out the exhaust it came!
Probing under the valve cover I discovered the two exhaust valve springs broken. While removing the head I was keeping my fingers crossed there would not be any more damage! Luck was with me, the valve had just enough spring in it that it kept it off the top of the piston!!
My Rotax 912ul is a 1993 model and has the old style 2-spring setup. We are now AWP (awaiting parts) for 8, new style, single springs and associated hardware. They arrive next Wednesday, and they will ALL be changed, so the other three heads need to come off as well. I'll clean-up the heads and valves while I'm in there.
The plane is home in the shop where it was born, so it's easy to walk to work each day. Special working party for me, yay!

Called Hal and told him the good news and he said it wasn't uncommon to lose the phenolic thrust washer, after you lost a cylinder. The shaking does the washer in.
Needless to say, My Oshkosh trip is Deep-Six'd, but I'll be in an "UP" status in a few weeks!

Have fun guys. Next Year for sure!

IMG_2720[1].jpg IMG_2723[1].jpg IMG_2734[1].jpg IMG_2736[1].jpg

[Geek]

Bummer Brett!!! Both the valve and Oshkosh! I know you were really looking forward to that. Glad that you can get parts and do the upgrade now. Certain you'll get it done right and be back in the air.

G

[bbs428]

[QUOTE=Geek;111786]Bummer Brett!!! Both the valve and Oshkosh! I know you were really looking forward to that. Glad that you can get parts and do the upgrade now. Certain you'll get it done right and be back in the air.

G[/QUOTE


Thanks Gary.

It's a blessing in disguise that it all happened close to home, so I really can't bellyache too much... but I will anyway, lol