SonexBuilders.net

13brv3 wrote:What ever happened to the factory Rotax experiment? Has anyone seen an update, maybe a podcast I wouldn't have noticed? I'm really interested in how that prop is working, but for all I know they scrapped the plane. Hope not though.

The One Week Wonder Waiex is at EAA's Kermit Weeks hangar, having just undergone an extensive condition inspection. Several issues were addressed, including cooling improvements and the replacement of the main engine control unit "brainbox". The original unit was sending false lane faults and other erroneous information to the instrument panel.

After the condition inspection and associated work was concluded, I flew the airplane to verify that the new ECU was performing properly, and to check the cooling issues. There is still some tweaking that needs to be done, but progress was made on the cooling.

The airplane belongs to EAA, and they will be deciding how to proceed with the testing. My guess is, the airplane will wait till spring before flying again.

The prop works great! The plane climbs like crazy (at least with me in it solo). haven't had a chance to really start putting cruise numbers together yet. Hopefully will be able to put that info together as the flying progresses.

XenosN42 wrote:Send them an email and ask them?

That's the plan, but I figured I'd see if there was some update I had missed first.

I'm really interested in that Sensenich prop performance, but I'm not sure why because it's over $2000 now. I'd never be able to justify that for the little performance I might gain over the Warp Drive.

Rusty

The silence on this project is both deafening & disappointing.

I can only assume the Sonex /912 project has been shelved - too hard basket.

Disappointing as I have met with cooling issues in my Sonex/912 ULS and had hoped that Sonex may provide some/all of the solutions.

It appears Joe sneaked an edit into his earlier post with some good info. Thanks for that! I already sent an email to Sonex, so maybe they approved the release of info? Anyway, I didn't really realize the EAA owned the plane, and was in control of it's testing. Hopefully they'll take more of an interest next spring.

As for the prop, I'd love to have numbers. RPM in climb, FPM climb rate, cruise. I might ask Sensenich, since maybe they've received some feedback.

13brv3 wrote:It appears Joe sneaked an edit into his earlier post with some good info. Thanks for that! I already sent an email to Sonex, so maybe they approved the release of info? Anyway, I didn't really realize the EAA owned the plane, and was in control of it's testing. Hopefully they'll take more of an interest next spring.

As for the prop, I'd love to have numbers. RPM in climb, FPM climb rate, cruise. I might ask Sensenich, since maybe they've received some feedback.

I have the original Sensenich with the 64" x 81" it was very much over pitched (4700 in climb and 5000 FTLF) so I trimmed it to 60" which should have made it close to the newer 60" x 82"


This helped the overload problem somewhat but still only got 4900 rpm in climb and 5200 FTLF but it seems to have lost a bit of thrust too upon take off.

I purchased a 3 blade E-Prop which arrived a couple of days ago so I will install it and go test and see if it is much better than the 2 blade Sensenich.

Skippydiesel wrote:The silence on this project is both deafening & disappointing.

I can only assume the Sonex /912 project has been shelved - too hard basket.

Disappointing as I have met with cooling issues in my Sonex/912 ULS and had hoped that Sonex may provide some/all of the solutions.

The project has certainly not been shelved. There are a lot of things going on, both at Sonex and at EAA. Everything takes time, and there are only so many hours in a day and so many people to take on the tasks, and time (and modifications) cost money. So don't "assume" anything. (You know what they say about "assume"...)

13brv3 wrote:As for the prop, I'd love to have numbers. RPM in climb, FPM climb rate, cruise. I might ask Sensenich, since maybe they've received some feedback.

All things in their time, weedhopper. All things in their time. (Hint: Don't bother asking Sensenich.)

I got a really nice reply from Mark at Sonex, which he invited me to share.
Rusty

(Update from Mark Schaible)

One Week Wonder has a defective ECU, and EAA is waiting for a replacement from Rotax, so it hasn’t done a lot of flying this year. We are also still unhappy with the cooling, even after installing front-facing NACA inlets in the cowling. We want to try a different plumbing arrangement, but the bottom line is that dual radiators are not working out well. Our recommendation to everyone at this point is to replicate Casey Cooper’s installation, which he has proven incredibly successful in very challenging cooling environments. Now someone just has to come-up with a version of his set-up that would be compatible with tricycle gear aircraft.

Regarding the Sensenich prop, it’s been great. Here’s sample flight data from a prop-focused test flight we did last year:
- Climb: Approx. 1500 fpm @ 80 mph IAS
- Peak RPM during climb: Approx. 5300 RPM
- Cruise RPM: Approx. 5000 RPM
- WOT Cruise RPM: Approx. 5750 RPM.
- Speeds (average) @ 5750 RPM and 2700’ MSL:
o IAS: 150-160 mph
o TAS: 157-168 mph
- Speeds (average) @ 5000 RPM and 2500’ MSL:
o IAS: 120-122 mph
o TAS: 123-126 mph

We continue to be very happy with the Toucan exhaust system with the Sonex-specific tube bends they provided ( http://www.toucanexhaust.com/ ), and our prototype AeroConversions/Rotax prop hub extension is working out great – we haven’t rubbed any holes in the cowling with the prop hub. We’re also very happy with our inline-ducted conical air filter can. The prop extension and air filter can will be brought to market when we get some time to catch our breath. The Throttle Quadrant XL is working well too, but we want to refine it a little.

Honestly, the Rotax install has been very low priority over the past year as we were working through the lane light issue with Rotax (defective ECU) all while still being very frustrated by cooling and seeing that Casey has it knocked with an attractive, streamlined and low-drag cooling installation that customers can replicate (our Production Manager, Cris Nash, will be installing the Casey Cooper system in his Sonex-B, which he hasn’t had time to finish and fly yet). Other, more urgent priorities have been demanding our time.

Feel free to share any/all of the above with other builders and the SonexBuilders.net community and thanks again for reaching-out.

Regards,
-Mark

Casey Coopers explanation of his cooling system is good BUT it would have been nice to see how he had done it .

For those who haven't seen the airplane since it was painted, here she is sitting in the EAA Kermit Weeks hangar.