SonexBuilders.net

I am assuming here, more than a few of you here know about Jan Eggenfellner's past history with the Subaru engines.

I was browsing his webpage today with the Viking engines. He does mention briefly his failed Subaru company in the one section.

Would you put faith in the Viking setup?

Gearboxes on the Subaru were one issue. DIY gearbox design by a non engineer seemingly one of the issues with that. In fairness, many products for sale to the experimental group are put out by people with no engineering background at all. Not a big deal for a seat cushion. Much bigger safety of flight issue for reduction drives and other parts.

I don't see any legit engineering history behind the Viking gearbox, so that is more than a bit worrisome.

I can sit down with some CAD program I got off Ebay last week and come up with some 3D views of some "aviation part" and sell them as plans if I so desired. Am I an engineer? No. Am I qualified in any way to design and manufacture a gearbox? Hell no. But I could! And THAT is the scary bit about some vendors at these airshows.

We all have the right to get smarter and learn from past mistakes. And I give him credit for actually having the guts to show up at Oshkosh and Sun N Fun, where he no doubt got ear fulls from more than a few of the Subaru crowd that got left to their own devices. He didn't pack up and go into landscaping design. He is back at it. So obviously his interest and motivation are still there.

And it seems he is having success and getting quite a few Viking installations in various planes including the Sonex.

On the surface, the Viking engine seems fine and early reports good. But on the surface the Subaru seemed fine too....and then

Just makes me wonder.

I think it may be best to keep my answer generic, but overall I do find the Honda Fit engine to be an intersting idea. Obviously, Honda engineering is great as they make some amazingly reliable cars.

When looking at auto conversions though, there's a lot more to look at. Is the design well tested and proven? Is product information accurate, reliable, and easy to find? Does the company producing the kits have a history of integrity? Unfortunately, when looking at Viking, it seems the answer to these questions is 'No'.

I wish Jan the best of luck and hope he's able to produce a quality product. For my money however, I want a proven product from a reputable company.

IMHO, there's just no need to put a Honda engine on a Sonex... Especially now with the Aerovee Turbo available. You have a range of horsepower from 80 to 120, at a range of budgets, and all are simple direct-drive air-cooled engines.

An auto-conversion (other than the Corvair) requires:
1) A cooling system [yay more pipes and fittings that can leak and ruin your engine, airframe, or electronics]
2) A drive-reduction system [belts or gears or whatever, and you have to worry about how they interact with both the engine and the prop]
3) Proprietary/uncommon engine electronics and control [what's the supply-chain like, and are you locked to 1 supplier for customized bits?]

When compared to an air-cooled direct-drive engine, its not just a couple of parts that you're adding to an engine - its whole new firewall-forward systems that will need to be configured, installed, monitored for wear, adjusted, and maintained over time.

The Viking engine claims to put out 110hp and weigh about 180 lbs. Now add coolant and you are really darn close to either the Aerovee Turbo or the Jab3300 in weight and performance. And on top of that, the Viking requires 87 octane fuel. And the website mentions wiping the engine down with WD-40 and not washing it... methinks there may be electronics or other parts sensitive to getting water - so no flying in inclement weather then I suppose?

I'm ever-hopeful for a lightweight, robust, inexpensive, high-HP engine; but as of today the "TANSTAAFL" principle is still in effect. :P

--Noel

We're probably kicking a dead horse here,
I think the AeroVee Turbo has pretty much killed the Sonex market for the Viking. There's just no need for it anymore, why would you take the risk now?

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Personal I feel there is room for the Viking engine. It's an Experimental engine, as much so as the Sonex is an experimental aircraft. While I also will be going the VW route for the mostly the same reasons many are, if I had more of an experimental mindset I'd try something I felt was appropriate, and it could possibly be a Viking.

Even our trusted VW engines at one point were untrustworthy, it was only through the diligent work of John Monnet in tinkering with it and having the support of his other Experimental builders. The history of Jan is questionable by some, with right. But, he keeps coming back with a new idea. Either it's delusional, brilliant, or somewhere in between... I don't know. But I give him a bit of credit for being inventive and a bit hard headed in his pursuit of another experimental engine.

Let's not slam the door shut to quickly...