Sonex-A purchase - What to look for

[Kai]

Get the prop dynamically balanced.

I'd argue this is a nice to have, not a must have.

I`d argue that what is a must have, is a crankshaft that stays in one piece- and anything that can be done to increase its useful life, is a must. Dynamic balancing will reduce harmonics and torsional vibrations (a well known and documented crank killer) in the crankshaft. All the VW-1 aeroderivatives I know of have one massive configuration error, as the main pto is at the structurally weaker end of the crank. The pto should be from the flywheel end, as many others have underlined before me- Bob Hoover among others. Look at the Sterling work William Wynne has done with the Corvair engine with the addition of the flywheel end bearing and the prop drive flange on the flywheel. The result is that this automotive unit has now become one of the more reliable aircooled powerplants for the Sonex.

[BRS]

I've a freind who put one of these (https://www.balancemasters.com/aircraft.html) on his RV-6. We checked it with the Dyna-Vibe before and after the installation. In this case his controllable prop was out too much (you can really feel it - not good) as ring didn't have enough weight to do the job. It did remove a bit more than half the vibration. This thread got me to wondering if one would fit behind the Prince prop ok. I might have to give them a call.

It's bassically a ring part filled with murcury (quick-silver as they call it).

[Hambone]

Buying new heads from Sonex, is it worth sending the heads straight to a VW specialist to have better valves and a valve job done before installation? Would this be any different than having better quality valves installed for VW automotive applications?

If the baffling is tidied up, would better quality valves reduce the possibility of valve damage again?

[Bryan Cotton]

Buying new heads from Sonex, is it worth sending the heads straight to a VW specialist to have better valves and a valve job done before installation? Would this be any different than having better quality valves installed for VW automotive applications?

If the baffling is tidied up, would better quality valves reduce the possibility of valve damage again?

I'm going to bolt on my new Sonex heads right out of the box. I'm going to rebuild my old heads with the best parts I can find.

[Hambone]

Buying new heads from Sonex, is it worth sending the heads straight to a VW specialist to have better valves and a valve job done before installation? Would this be any different than having better quality valves installed for VW automotive applications?

If the baffling is tidied up, would better quality valves reduce the possibility of valve damage again?

I'm going to bolt on my new Sonex heads right out of the box. I'm going to rebuild my old heads with the best parts I can find.

Are you doing this soon?

[Bryan Cotton]

Are you doing this soon?

I have new heads on order due to compression loss in cylinder 3 as I posted elsewhere.

[Hambone]

The further I go down this rabbit hole, the more I realize that buying an airplane with an AeroVee was a foolish and ill-conceived move on my part. Sonex advice is that if you don’t have the requisite ability or desire to build one of their airplanes, perhaps you shouldn’t own one, either. I get that now.

[daleandee]

The further I go down this rabbit hole, the more I realize that buying an airplane with an AeroVee was a foolish and ill-conceived move on my part. Sonex advice is that if you don’t have the requisite ability or desire to build a one of their airplanes, perhaps you shouldn’t own one, either. I get that now.

Don't let the lessons you've learned distract you from the fact that you own a very nice airplane! VW engines are challenged when working as hard as they do in these airframes and other similar planes. I don't say that to be negative it's just the way it is. A 2180 will fly these planes and with great attention to cooling and operation you will get fair service from the VW conversions. It just a truth that the valves and heads take a beating and that's the weak point. This is not a secret.

Many that fly VW airplanes keep a set of fresh heads on the shelf so as they can be swapped out in a few hours once you get into the groove of how it's done.

In reality heads for VW conversions are inexpensive compared to certified aircraft. Once you have a second set then (like Mr. Cotton is doing) take the first set and have them redone and set them on a shelf. In a hundred hours swap them out and have the next set redone and placed on the shelf (time to replace will vary - I first had to pull the heads at 65 hours for exhaust valve leakage on my aerovee).

As I said earlier, I flew a VW conversion for ~5 years, did a lot of work/research and realized it wasn't the engine I wanted on my plane. I have a list of reasons for why but it's just a personal choice. The VW conversions do work, they just take a lot more maintenance than the other engine offerings.

Dunno if this helps ...

Dale
3.0 Corvair/Tailwheel

[bvolcko38]

As I see it, the elephant in the room is Chinese parts made of Chinese materials.

[Bryan Cotton]

As I see it, the elephant in the room is Chinese parts made of Chinese materials.

Amen!