What am I missing?

[gcm52]

There really are two big decisions when building a homebuilt. Choosing the airframe and choosing the engine. I think Sonex is missing a business opportunity by not supporting more engines. Why not engineer a FWF kit for all major 80-120hp players that would work with the airframe? Rotax, UL Power,Corvair? They could make money on the FWF kits and sell more airframes. When your market demographics are not growning (not many new pilots coming into the market) you need to offer more to the existing market. Yes it would be more engineering, inventory, etc. to have more FWF kits, but a lot of engineering/inventory cost went into the Subsonex with an uncertain payback (although the Subsonex project I suspect was driven by more than just business considerations). My bet would be that they would make more by selling more airframes than they would lose by lost aerovee sales.

[NWade]

So after reading all you posted and much searching on the internet I have come to a conclusion: The Sonex airplane is an excellent airplane but the motors that Sonex supports are questionable. When I search on the internet and read other forums (as well as this one) I don't get warm fuzzy feelings about the Aerovee or the Jabiru engines.

John -

Please remember that people are more likely to post or make noise when they're unhappy. Happy pilots are mostly off flying instead of sitting in front of the keyboard. ;-) Also, remember that any yahoo can post anything they want online - even if they have no facts or experience. I've seen folks slag engines and airframes as unsafe or unreliable (and say it with authority and conviction), without ever having seen them in real life! This happens even in the certified-aircraft world when people get into debates between Continental & Lycoming engines. (For fun: try wandering into a forum and ask about the different cam-shaft positions & lifter styles, between Conti & Lyc. You're guaranteed to see a good argument get going!)

When it comes to the engines you mentioned, the factory's position has always been that engines like the Rotax are a great deal more-expensive and more-complicated than necessary. Sonex Aircraft has repeatedly stated that their mission is to provide a fun, relatively-low-cost aircraft. Since they don't see the Rotax as a "necessary" part of that equation, they don't spend time or money on making it an officially-supported option.

But there's nothing stopping you from putting a different engine in the Sonex, if you truly cannot bring yourself to install a VW or Jab engine. The factory won't help you, or endorse the end-result; but they won't stop you either. There are at least 2 Sonex airframes with Rotaxes installed, and there are also folks with Corvair engines as well. However, before you head off on that adventure I strongly suggest you learn about how engines are designed, built, and maintained. A little education and experience will help take a lot of the mystique and nerves out of the equation. I myself am lucky in that I used to do some auto-racing and had the chance to help with the re-build a couple of engines & gearboxes; so I speak from personal experience when I say that some learning and hands-on experience is really valuable and reduces the mystery & concern!

Going back to the factory options: the staff have stated that they feel the engines they offer are safe, affordable, and "good enough" to meet the mission of providing safe & affordable fun-flying. Given that there are several hundred of these airplanes flying - and using these engines - I don't disagree with them... Sure, you can find evidence that a few aircraft have had engine problems; but that's ANY aircraft (not counting the fact that there is always going to be some percentage of folks out there who build it poorly and then blame the factory when it comes apart). But we're not seeing news reports of mass casualties, nor do we see the entire fleet being grounded (like another homebuilt model, which I won't mention here).

Bottom-line: Experimental aircraft is about making your own airplane - and that includes the engine and other components you choose to put in it. Arm yourself with facts, learn the pros & cons of each option, and then make the choices that are right for you. Have fun and good luck!

--Noel

[SonexN76ET]

John,

You are on the very first step of possibly building your own airplane, namely that of dreaming and doing online research. However, I do not think you are serious. I think you are just a dreamer. Please prove me wrong and go look at the various planes you are interested in. Possibly get a ride in one. Go to a Sonex Builders workshop or an RV SportAir workshop. See for yourself! Don't just rely on the cyberspace for your answers. Go the the Oshkosh Airshow for heaven sakes!

Finally, there is so much hype and B.S. on line and in print. If you read the aviation magazines, for the last 11 years they have all been touting what a remarkable airplane the Icon A5 is. It has gotten so much positive press, been featured on the covers of almost all the aviation magazines. It has all been hype! The company has yet to produce one production aircraft. Yes, the prototype looks cool, but the company has yet to deliver. Same thing goes with the UL engines. Lot's of hype, but not enough of them in service to prove the engine's durability or reliability.

If YOU are not comfortable building your own engine, you also have the option of going with a Revmaster or a Hummel engine or a Great Planes engine. These are also VW based, but they are factory built. Many people power their Sonex aircraft with these engines and are very happy with them.

IF you have the financial means to shell out $90,000 for an RV12, go for it. Or if you dont, just keep dreaming about it and do nothing (I did this figuring I would someday afford and RV8, but never could). IF YOU HAVE $2,000 bucks or so laying around, you can buy a Sonex tail kit and get started right now and have your plane completed a few years from now with a total outlay of around $30,000. I quit dreaming about an RV8 and I built and now fly a Sonex. I AM HAVING THE TIME OF MY LIFE FLYING THIS FANTASTIC LITTLE SONEX!!!! As far as dreaming goes, I NOW DREAM ABOUT BUILDING AND FLYING A SUBSONEX JET!

One other thing about the Sonex, with a stall speed of 37 mph or so, its stall speed is comparable to many ultralights that fly behind 2 stroke engines and have an open cockpit. If you have an engine quit and you keep the plane under control, the resulting landing should be no worse than running your four wheeler off the road into some bushes at 37 mph. But, if you look at the NTSB reports and figure that thereare over 1,000 Aerovee engines flying, you will see that they are pretty darn reliable.

I hope you prove me wrong and do something tangible other than just dream...

Jake

[rizzz]

So after reading all you posted and much searching on the internet I have come to a conclusion: The Sonex airplane is an excellent airplane but the motors that Sonex supports are questionable. When I search on the internet and read other forums (as well as this one) I don't get warm fuzzy feelings about the Aerovee or the Jabiru engines. I know much of what I read is not based in fact but considering the volume of criticism, my confidence level is low on these engines. When I search for negative information on the Rotax 912 I don't come up with much. I know Sonex wants to keep it simple (also interpreted as inexpensive) so if they supported the Rotax the cost of a Sonex wouldn't be much less that a RV-12 or a Zodiac 650 but a Sonex with a 912 would be a good combination.

Hi John,
This post seems to imply that Sonex only "supports" the AeroVee and the 2 Jabiru's.
Now, it is debatable what "support" means in this case, however, have a look at the engine section on the Sonex drawing tree:

Notice how the drawings say "Volkswagen engine" and "Volkswagen conversion".

The Sonex airframe "supports" all standard VW conversion engines, not just the AeroVee. The drawings that detail the installation are not AeroVee specific.

Off course, given the AeroVee is Sonex LLC's own product the level of "support" you will get from them when you install it vs. another VW conversion will be much higher.
BUT! Unlike a Rotax912, you can install any of the major VW conversions with little or no modification to the engine mount etc. and the plans detail how.

[DCASonex]

In addition to the various Volkswagen engine alternatives, there is a drop in alternative to the Jabiru engines as well, CAE - CAMit Aero Engines, offers 2200 and 3300 engines based on same original design but with many improvements most all of which are intended to improve reliability. They are new and do not yet have a US distributor, but should soon. I have one of their 3300 in front of my Sonex and it is doing great.

David A.

[WaiexN143NM]

To DCASonex,
David, did the cammit 3300 drop right in ? , I have seen some pictures looks like a bracket and alternator on the back side. Any clearance issues with the standard factory jab 3300 mount? And what changes or improvements on the cammit vs. jab engine? Thanks!

Michael Radtke

[WaiexN143NM]

Also David, what was the cost in US Dollars?

[SvingenB]

It’s been said that the cost of an aircraft can be divided as follows: Airframe ⅓, engine ⅓ and avionics ⅓. A very rough and inaccurate estimate I am sure, but it’s an easy thing to remember and keep in mind.

A Sonex kit costs 16.5k (quick built almost 30k), avionics costs 3-10k, the engine costs 8-20k.
An RV-12 kit costs 23k, avionics 13k, engine 29k (from Vans) about 20-24 k elsewhere.
An RV-4 kit cost 17k, avionics 2-20k (but the sky is the limit), engine 22-24k (Lycoming clone)

It is obvious you can cut costs by: Opting for less prefabricated airframe. Going with more reasonable avionics/instruments. A cheaper engine.

For the Sonex it is straightforward to cut cost, it is part of the design and philosophy. For the RV-12 it is definitely not. For the RV-4 it is also rather easy by getting minimum instruments and a used Lycoming.

My point is that lots of RV-4s are built for a whole lot less than a typical RV-12. But there are also lots of RV-4 that are built for much more than an RV-12, which is very easy simply by getting a brand new certified Lycoming, CS prop and IFR avionics. The other thing is of course that the airframe kit itself does not vary that much considering similar size, similar materials and similar state of prefabrication. Also, with a quick built Sonex at 30k, a Rotax 912 at 22k is a very reasonable deal, the engine will still cost less than the airframe (the total cost will of course soar though, but not more than a RV-12).

[DCASonex]

My CAMit engine did drop in, but I did not get the external alternator. (My mistake, will be converting to that.) There is a new alternator mounting made specifically for Sonex, and I think testing a smaller and much lighter 20 amp unit as alternative to the 40 amp both options being belt drive will still charge at low RPMs.

I bought mine a year go when the dollar exchange rate was near equal Since then Australian dollar has dropped, and US dollar risen. Last I looked, Australian dollars were now worth about 75 cents US. Big discount for us in the US. If interested, CAMit's web site is >> camitaeroengines.net <<<< look at top of page for engines section, is does not stand out, or contact them at >>> sales@camit.net <<<.

David A.

[sonex1284]

Don't try this in your RV-12 or Zenith! https://www.youtube.com/watch?v=u-v56I0AVEQ