Broken tooth on starter ring gear

Jamie · #1 10-10-2008, 01:46 PM

I discovered a broken tooth on my starter ring gear last weekend. I have not ever noticed a kick-back or any rough starting with my engine. Anyone have any ideas what may have caused this?

Also, should I be worried about it? I think it will be fine, just as long as the broken tooth isn't aligned perfectly with the starter when I attempt to start.

I am currently attempting to get a new one from Superior.

andyrv · #2 10-10-2008, 02:42 PM

Which starter do you have?

Andy

Jamie · #3 10-10-2008, 02:57 PM

Quote:

Originally Posted by andyrv

Which starter do you have?

Skytec lightweight.

Don Jones · #4 10-10-2008, 03:15 PM

That broken tooth will eventually eat up the drive on the starter. Better replace it now! Especially since the Skytec starters tend to break the end frame quite easily.

DaX · #5 10-13-2008, 06:34 AM

A single broken tooth can have a cascading effect which is disasterous. When that part of the ring gear comes around to the starter, the starter can spin freely, even if only for a fraction of a revolution. This allows an impact force to be placed on the next tooth on the ring gear. Repetition of this will fatigue the tooth until it breaks. Now you have two teeth missing. Next time you start and go past the section missing two teeth, the starter can spin even more freely, and impact the next tooth harder. Eventually you get to a point where most of the remaining if not all the teeth shear off at once. Ask me how I know...

tommylewis · #6 10-13-2008, 08:51 AM

Check your Superior ring gear to ensure it has the "guide" to help the starter engage okay. On my first flight 18 months ago, I had a tooth break off on start up. An examination of the ring gear, and comparison with other normal ring gears showed that Superior had made some that did not have the liitle groove to help guide the starter to engage. The engine builder, AeroSport replaced it with no question.

While you have the ring gear off, send the starter into SkyTec to be checked because I am told the starter is designed to break first. I had a kickback this summer, thought my ring gear might be toast, it was not, but my starter was damaged, it still worked, but I had it checked out by Skytec and they rebuilt it.

Jamie · #7 10-13-2008, 12:16 PM

I finally had time to give Superior a call this morning and they said they would send me a new ring gear, no questions asked! Great customer service.

Hopefully I will not have a repeat occurrence.

Jamie · #8 10-16-2008, 08:23 PM

I received a new fly wheel from Superior yesterday and installed it today. Comparing the two flywheels (or more specifically, the two ring gears) side by side, there is a noticeable difference in the machining. On the aft side of the teeth on ring gears there is a little notch which radiates inward. This notch is presumably there to help the starter gear engage the teeth. The notch on the failed ring gear is tiny compared to the notch on the new ring gear. I took a picture on my cell but unfortunately it did not turn out. I will take better pictures with my camera and post them for comparison purposes.

Anyway, hopefully the problem is resolved for now and there will be no other issues. Unfortunately I now have to fix my airbox problems I discovered when I pulled the cowl. :-)