SonexBuilders.net

Greetings,

I've built a handful of planes before, mostly RVs, and I got out of the airplane hobby about 8 years ago. I was in the western panhandle of FL, which is one big mess of airspace with all the military. The part that wasn't military was either ocean, or flat pine tree farms. I eventually just got tired of flying around all that.

Well now I'm in Eastern TN, and I'm going to build a Onex. This is a design that came out after I got out of flying before, and it's almost exactly what I've been looking for. I had an RV-3, so I'm fine with single place, and I've always wanted wings that fold like the Onex. I haven't bothered renewing my medical since I quit flying, and the performance they manage to get within the Sport Pilot limitation is impressive. There's no reason I couldn't renew my medical, but it's a hassle I'll be happy to avoid.

I was able to look at a half finished Onex at the Crossville fly-in this past weekend, and I also looked at a nearly complete project yesterday (thanks Stan!), so this morning I ordered the full kit (with machined angles, and complete spar). This needs to be a fast build, because we have to be out of this rental house by the end of next May. I'll be pushing to get it mostly finished, to the point of being ready to move to a hangar at least, or a storage building temporarily if needed. The rental house has a great heated and cooled garage to use for building, so I'm going to take advantage of it before we move up to our eventual (smaller) mountain home.

My only real question for the moment is about the engine. I've always been a performance oriented guy, and the turbo is very hard to resist for only a couple thousand more. Sonex confirmed that they initially tested it on a Onex mount, but the space was somewhat limited. They said one person was building one now, so it would be interesting to find out more about that. It's absolutely not anything I need, but it's something I have to consider.

Cheers,
Rusty

Edit- I caved and order the turbo engine :)

Rusty,
I am not putting a turbo in my Waiex (yet) for two reasons - money and I want only 80 HP to train my kids with. One potential barrier for you would be the lack of turbo Onexes. As a repeat offender, is that really much of a barrier? I am guessing not. A turbo Onex would be cool!

Welcome to the tribe!

Hi Bryan,

I had a Mazda rotary engine in the RV-3, so I have a history of putting things where they don't belong :-) I think I would probably enjoy the challenge of the turbo installation, but I need to consider that I'm under time constraints, so it makes sense to stay as close to "normal" as possible.

I'll almost certainly stay with the 80HP initially, then plan to convert it later if I find myself looking for more work to do :-) I actually planned for my next airplane to be electric, so maybe in a few years I can consider an electric motor if it becomes more feasible.

Cheers,
Rusty

I thought the turbo was designed to fit all Sonex models including the Onex.

fastj22 wrote:I thought the turbo was designed to fit all Sonex models including the Onex.

My understanding as well, I'm a little surprised if they're anything but fully supportive of the turbo in the onex airframe.

Rynoth wrote:

fastj22 wrote:I thought the turbo was designed to fit all Sonex models including the Onex.

My understanding as well, I'm a little surprised if they're anything but fully supportive of the turbo in the onex airframe.

Everything I see on the website seems to indicate that the turbo is intended to be fully supported for the Onex. They were just warning me that it's early, and there aren't flying examples yet. It would probably take a bit more thought and space management now, compared to later when there are several successful examples.

I'm still mighty tempted, but I worry that it may not sneak past the sport pilot limitations. It really just depends on how the engine is rated for continuous power, and maybe whether you lean toward a climb or cruise pitched prop. I guess I'm also worried that it's a lot to ask from a tiny little engine. I'm not really familiar with VW based engines, so it's something I have to do a lot more research on.

Cheers,
Rusty (road trip to get my old tools back)

13brv3 wrote:Hi Bryan,

I'll almost certainly stay with the 80HP initially, then plan to convert it later if I find myself looking for more work to do :-) I actually planned for my next airplane to be electric, so maybe in a few years I can consider an electric motor if it becomes more feasible.

Cheers,
Rusty

Make sure you plan your firewall around the turbo. I have a AeroVee Sonex and have a nicely laid out firewall. Unfortunately if I want to go to the turbo it will require relocating a LOT of stuff. And drilling stainless steel is a real PITA! So if you have an eye toward the turbo, plan in advance.

13brv3 wrote:

Rynoth wrote:

fastj22 wrote:I'm still mighty tempted, but I worry that it may not sneak past the sport pilot limitations. It really just depends on how the engine is rated for continuous power, and maybe whether you lean toward a climb or cruise pitched prop.

The turbo engine is only rated for 80hp continuous, which at sea level would give the same performance as the standard aerovee, which is all the sport pilot limitations care about. The extra power from the turbo is mostly for takeoff-climb, and higher engine output at altitude.

From the regs: "A maximum airspeed in level flight with maximum continuous power (V H) of not more than 120 knots CAS under standard atmospheric conditions at sea level."

The turbo should meet that requirement the same as the normally aspirated aerovee, since both are putting out 80hp max continuous.

mike.smith wrote:
Make sure you plan your firewall around the turbo. I have a AeroVee Sonex and have a nicely laid out firewall. Unfortunately if I want to go to the turbo it will require relocating a LOT of stuff. And drilling stainless steel is a real PITA! So if you have an eye toward the turbo, plan in advance.

This is the main reason I'd want to do the turbo in the beginning, rather than as an upgrade. It would be a lot easier to work around the turbo when it's bolted in place, rather than trying to guess from pictures how much space you have. You do want to get the firewall penetrations correct the first time, and not have extra holes because you moved stuff.

Cheers,
Rusty

Rynoth wrote:
The turbo engine is only rated for 80hp continuous, which at sea level would give the same performance as the standard aerovee, which is all the sport pilot limitations care about. The extra power from the turbo is mostly for takeoff-climb, and higher engine output at altitude.

Is that posted somewhere on the web page? The only thing I could find was the max continuous rating limit of 35 in Hg MAP. While that sounds like more than standard power, there are some losses in turbo systems that require more than 30" to get back to normally aspirated power, so that "may" be 80HP?

I see that they offer a climb and cruise prop as well, so choosing the climb prop would help.

Thanks,
Rusty