What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

What is that sound!?

New owner. Rotax 912ULS, at ~23 tach hours. Today I heard something while taxiing, after landing. There's a squeal just loud enough to hear over the engine, that comes and goes depending on RPM. Engine instruments all in the green. Here's a 1 minute video that caught it as I tried different RPMs.

https://youtu.be/Q-LDRCt3pS8

Tomorrow I'll talk to the mechanic, but it's not like I'm going to get any sleep before then! What do you think?
 
I had a screech when pulling the prop through to burp the oil, but nothing like this. I?d pull the magnetic plug and filter to see if there is any metal on them. The ROTAX 912 can make some strange noises, but I would be concerned too. Did you purge the oil lines when you did the initial install?
 
Problem identified and solved; or so I'm told. I'll see it tomorrow, but it has something to do with (insufficient) lubricant between the spinner and some part of the pitot.
 
Problem identified and solved; or so I'm told. I'll see it tomorrow, but it has something to do with (insufficient) lubricant between the spinner and some part of the pitot.

Was going to suggest looking at the pitot tube/spinner bushing interface as well as confirming clearance between spinner and cowl (although the noise on the latter would change pretty quickly as it wears, and would more likely occur when new).
 
Good catch! I never would have thought of that. With regard to wear on the tube mine has a polished appearance. The first pitot tube circumferentially cracked at 670 hours and failed at the flat spot where the anchor screw pins it. I did not file the flat spot on replacement tube and have had no issues in 320 hours.
 
Back
Top