Sonex-A purchase - What to look for

[BRS]

Hi Brock,

Yup! Revmaster vs Aerovee design choices. I'll probably not take the time but it would be interesting to mount a temporary probe like in the aerovee instructions just to see how different the two locations are.

I know it's a big ask, but if you get a chance please do. It would be valuable information.

Also, you wouldn't happen to have a pic of the thermocouple tip. Just wondering how the junction is made. Cr/Al or Copper Con?

Edit: What is that black adhesive used to secure the T/C wires?

Thanks,

Wes

Wes, the RTV (my favorite) I buy at Napa (National Aircraft Parts Association). The junction looks to be a simple weld. I believe this kind of probe can be twisted and crimped. I'll see about doing a ground run comparason test.

[BRS]

So the joke was to mount the probes where they made you feel the best and just go fly the thing! 8~)

Dale, not just a joke but an actuall practice. I've a friend who flies an origanal c-172 straigt tail. They had trouble with the oil temps during certification on those planes. The fix was to install a blast tube pointed at the oil temp sensor. (at least that's how I understand it) Amazing, on a certified plane.

[WesRagle]

Wes, the RTV (my favorite) I buy at Napa (National Aircraft Parts Association). The junction looks to be a simple weld. I believe this kind of probe can be twisted and crimped. I'll see about doing a ground run comparason test.

Thanks,
Wes

[Kai]

Hi Brock,

I know it's a big ask, but if you get a chance please do. It would be valuable information.


Edit:

Thanks,

Wes

Following!
Kai

[bvolcko38]

In my experience, the Aerovee valves do not rotate at all. Even though my rockers were set up as per the plans, I see absolutely no evidence of valve rotation. I've had both heads off at different times and there is no exhaust valve rotation whatsoever. There is no way the lubed rocker with an arm of a couple millimeters can overcome the friction of the valve spring. Certified, and other engines have valve rotators.

[daleandee]

In my experience, the Aerovee valves do not rotate at all. Even though my rockers were set up as per the plans, I see absolutely no evidence of valve rotation. I've had both heads off at different times and there is no exhaust valve rotation whatsoever. There is no way the lubed rocker with an arm of a couple millimeters can overcome the friction of the valve spring. Certified, and other engines have valve rotators.

My Corvair and those conversion engines built by Dan Weseman or William Wynne have rotators on the exhaust valves (very early models may not have them. Easy enough to check).

Dale
3.0 Corvair/Tailwheel

[BRS]

I had an A&P friend (now flown West) who used to test lycoming valve rotation by repetitivly tapping the rocker with a mallot. You could watch the valve stem turn. Takes some thought so you don't end up pounding on the push rod thus bending it.

[Kai]

In my experience, the Aerovee valves do not rotate at all. Even though my rockers were set up as per the plans, I see absolutely no evidence of valve rotation. I've had both heads off at different times and there is no exhaust valve rotation whatsoever. There is no way the lubed rocker with an arm of a couple millimeters can overcome the friction of the valve spring. Certified, and other engines have valve rotators.

That´s interesting!

With some working experience with the major european makes of VW-1 aeroderivatives, Limbach and Sauer, I have done a certified service rep tech course on them both. There is no doubt that the exhaust valves on these rotate as advertised. But no rotators- just the tappet hitting the stem off centre.

Why would it be different on Aerovee? Perhaps different production setups in Mexico?

[Area 51%]

Why would it be different on Aerovee? Perhaps different production setups in Mexico?

Mexico?
The cases are manufactured in Brazil, the heads in China, cranks and cams home-grown.

[Kai]

That was not such good news. I have an aquaintance whose Aerovee powered Sonex had a crank failure right in front of the first web after some 80 hrs. The front of the crank, the 2 blade wooden Sensenich prop and the scullcap spinner came down in a busy mall parking lot. Nobody was amused. So he decided to go for a Great Plains motor- which held out a little longer. But this crank also broke in two, this time across the last web in front of the flywheel. He decided that there had to be something better that would last at least a couple of years.