SonexBuilders.net

MichaelFarley56 wrote:Does anyone else have any stories or questions?

Stories? Hoo boy have I got stories!!! :) Over the course of time I will add a few here to this thread. But first, let me add my kudos to Robbie for getting this started. We cannot emphasize enough our need to have safety at the forefront of our minds at all times. With respect to what others have commented, I submit that flying IS hazardous (so is driving your car, riding a motorcycle, scuba diving, riding horses, and many other recreational pursuits). There is always room for improvement on the safety front, and all of us need to strive to be as cautious and conscientious as we can be, so as to continue to improve our safety record. The FAA constantly shines a bright light on the experimental aircraft safety record, and if it continues to lag behind their target numbers you can bet they'll take action. But for EAA and other interested parties, they already would have!

Please fly safely, for your benefit and for all of ours.

Keith,
Thanks for the numbers and analysis.

kmacht wrote:I would like to get back to the fuel line / ethanol thing for a minute. For those of you who have had problems with the fuel line when running ethanol could you let the rest of us know what brand and/or part number you were using? The aerovee and aerocarb is supposed to be ethanol compliant so the only failure mode from using mogas would be the fuel line itself. If you are using the braided line that sonex recomends for the oil lines (JEGS P/N 799-632060) for your fuel line it is supposed to be ethanol compatable. If that is what is being used it leaves me wondering why people are having it swell up on them.

Keith
#554
1.2 hours

I'd also like to hear more discussion about this. I spent far more effort than I expected selecting stainless steel braided hose due to the large selection of manufacturers, polymers, hose ends, etc.

I ended up using this PTFE (Teflon) hose: http://www.summitracing.com/parts/FRA-603006 . My research led me to believe that there is no reason for me to use anything other than a Teflon hose due to its superior chemical compatibility--it even costs about the same as other hoses. Once I narrowed down to only Teflon (PTFE), the selection became much simpler.

The hose quoted as being recommended by Sonex is lined with Chlorinated Polyethylene (CPE) which according to several chemical compatibility charts is not as good as Teflon for gasoline (This chart recommends it for intermittent service only http://www.alliancehose.com/pdf/chemica ... -chart.pdf). That being said, CPE seems to rank on par with Teflon for Ethanol compatibility, so I would be surprised if the problematic hoses mentioned previously were the recommended one.

I think everyone here has some great ideas on safety.

I would like to add that we include key inspection items from experienced Sonex aircraft builders and pilots. What are key areas that should be inspected for wear? What are the wear limits? What items need to be replaced periodically? What items are prone to failure? We need to share each others experiences to make the fleet safer on an ongoing basis.

We also need to provide peer reviewed and validated tips and tricks (lessons learned) for building and for operating the Sonex aircraft. Too much on these forums turns out to be hearsay or simply one person's technique. If something works well for more than one builder and can be validated then that tip or trick or technique could be placed into our experience vault. If a tip or trick or technique turns out to be bogus, it should be deleted from that knowledge vault. A key example is Keith's question on how to handle fuel with ethanol, we need to have a solid answer for this. It should not be guess work.

I for one, would like to see enhanced information on how to tune the AeroInjector and how to test the AeroInjector on the ground before flight. I had to learn the hard way. One set of flights I had my AeroInjector way too lean and on another set of flights way too rich. I found most of the posts on the foundation site too vague and had a bit of a challenge following the AeroInjector manual. For instance, I saw many posts about how you had to be real rich on idle and had to lean for taxi and then go to full rich for take off etc. Well, I took that advice and set my needle too rich and had my engine loose power on takeoff and I had to abort my takeoff at 50 feet AGL but had plenty of runway still ahead. Needless to say, it put the fear of God into me. I still don't have all the answers on how to get it perfect. For example, if you try to adjust the mixture needle without remembering to lock the throttle in the full open position, the AeroInjector will behave "funny" (act too rich or too lean perhaps from twisting the slide or the throttle cable?) for awhile when you try to run the engine. Just an example of what one might encounter during the tuning process.

So perhaps the advice in the forums needs to be shifted through, organized, and peer reviewed then put into a knowledge vault that builders and pilots can go to with some level of confidence.

Safety needs to be a top concern of this foundation.

kmacht wrote:The cause with the highest number of incidents was a loss of engine power for unknown reasons. Those totaled 8 but only 3 were fatal. A number of them were for unknown reasons because the aircraft was destroyed but there were also a few where nothing was able to be found wrong during inspection of the engine.

kmacht wrote:What worries me the most is the engine failures for unknown reasons. Without knowing why the engines failed it is hard to come up with a solution to the problem if there even is one common problem.

Is it known how many of those 8 were flying with an AeroCarb/AeroInjector?
I know this is a controversial subject but it does need to be discussed. I don't have a Jab or AeroVee but I do have an AeroInjector so I for one would like to know.

Also, the percentage of "loss of power for unknown reasons", is that comparable to what you would see in aircraft powered by more conventional aircraft engines like the Lycomings and Continentals or even the Rotax powered planes? (In other words, are we flying behind powerplants that are more prone to fail due to unknown reasons?)

rizzz wrote:Is it known how many of those 8 were flying with an AeroCarb/AeroInjector?
I know this is a controversial subject but it does need to be discussed. I don't have a Jab or AeroVee but I do have an AeroInjector so I for one would like to know.

Also, the percentage of "loss of power for unknown reasons", is that comparable to what you would see in aircraft powered by more conventional aircraft engines like the Lycomings and Continentals or even the Rotax powered planes? (In other words, are we flying behind powerplants that are more prone to fail due to unknown reasons?)

Personally, I think these are two EXCELLENT questions. Unfortunately, I'm not sure if we will be able to answer these questions very easily. I know there are a lot of opinions floating around the internet about the AeroInjector, but unless the airplane equipment information is specifically stated in an NTSB report, I'm not sure how we'd be able to find that information.

As for the coventional aircraft engines vs. experimental aircraft engines, we may be looking at something of an apples-to-oranges comparison but my gut tells me the accidents may ultimately be comparable. I've seen a lot of "loss of power for unknown reasons" reports even on certified engines. I do think they are investigated differently so there will be some variance; in a lot of certified aircraft cases, the NTSB investigates while most experimental airplane accidents are investigated by the local FSDO (FAA). And I've seen A LOT of cases where the FSDO looks for an obvious problem, turns the engine over to ensure compression, and if they can't find anything, it normally results in a "loss of power for unknown reasons" report.

kmacht wrote:I would like to get back to the fuel line / ethanol thing for a minute. For those of you who have had problems with the fuel line when running ethanol could you let the rest of us know what brand and/or part number you were using? The aerovee and aerocarb is supposed to be ethanol compliant so the only failure mode from using mogas would be the fuel line itself. If you are using the braided line that sonex recomends for the oil lines (JEGS P/N 799-632060) for your fuel line it is supposed to be ethanol compatable. If that is what is being used it leaves me wondering why people are having it swell up on them.

Keith
#554
1.2 hours

Keith,
All i can tell you is that I'm pretty sure my first fuel line was the Russell 632060 - Russell ProFlex Stainless Steel Braided Hose I purchased from JEGS and you read what happened to me. After this I bought aviation quality AeroQuip -06 line and haven't had an issue since, but I've also only ran 100LL since as well. Your mileage may vary...

Lots of good reading on the topic here:

http://www.ntsb.gov/doclib/reports/2012/SS1201.pdf

It is tough to compare one model of experimental aircraft to another since that data isn't available without doing alot of data mining on the ntsb database for each type. There are a few things we can compare though. From the report above it appears that powerplant issues in homebuilts are the #1 cause for non-fatal accidents at 23%. The sonex looks to be a little high for powerplant issues at 32% vs 23% but it is also fairly new in the grand scheme of homebuilts and the total number of aircraft is relatively small. There has been an uptick in accidents over the past few years but I would be willing to bet that there has also been an even bigger up tick in the number of aircraft completed and flying. The difference between us and other aircraft may very well be within a reasonable margin of error. It is just too early to tell. My point is that I haven't seen any solid evidence that the Sonex, Aerovee, or Aerocarb is any worse or any better than other designs out there. Regardless of if it is or not that doesn't mean we shouldn't be looking for ways to improve the record and reduce risk as much as reasonably possible.

Things like people having issues with Russel fuel hose not being ethanol compatible even though it is supposed to be are the type of issues we should be raising here. We want to find out about potential problems before we get on the NTSB database not afterwards.

Keith

SonexN76ET wrote:I think everyone here has some great ideas on safety.

I would like to add that we include key inspection items from experienced Sonex aircraft builders and pilots. What are key areas that should be inspected for wear? What are the wear limits? What items need to be replaced periodically? What items are prone to failure? We need to share each others experiences to make the fleet safer on an ongoing basis.

We also need to provide peer reviewed and validated tips and tricks (lessons learned) for building and for operating the Sonex aircraft. Too much on these forums turns out to be hearsay or simply one person's technique. If something works well for more than one builder and can be validated then that tip or trick or technique could be placed into our experience vault. If a tip or trick or technique turns out to be bogus, it should be deleted from that knowledge vault. A key example is Keith's question on how to handle fuel with ethanol, we need to have a solid answer for this. It should not be guess work.

.....

So perhaps the advice in the forums needs to be shifted through, organized, and peer reviewed then put into a knowledge vault that builders and pilots can go to with some level of confidence.

Safety needs to be a top concern of this foundation.

I can assure you that safety is exactly why we went to the effort to start the foundation, and remains our number one priority.

For this that missed it, please read the article from EAA below. Clearly, this is not just a concern among us.

http://www.eaa.org/en/eaa/eaa-news-and-aviation-news/eaa/2014-10-14-experimental-category-fatals-edge-past-faa-target

The wording from the FAA is, once again, strong.

We continue to request information, articles, links, and data from all of you to share. We do our best to only put on http://sonexfoundation.com that which is accurate and safe. While we do link to external content, it is always up to each individual to make their own decisions and this is where the forum can help, or confound.

The information on this forum is like the rest of the Internet - some good, some not much. It is always difficult to sort through the posts and know what to do. If someone is willing to take this on as a task, we would gladly publish any peer-reviewed results of the information they find. But as a reminder, it is Sonex Aircraft LLC technical support that is the final source of accurate technical knowledge for these aircraft.

Our next newsletter is already in progress with a hopeful November release. I am always looking for content, analysis, member aircraft to feature, and editorials to use.

This is an important and timely conversation that I hope all of us continue.

Robbie Culver
Sonex 1517
Chicagoland
Tails and Wings complete - finishing fuselage.
N1517S reserved

I think a good test to see if your fuel line choice is ethanol compatible is to take a section and put it in a jar of ethanol/gas. Let sit. Then see if it swells. I purchased braided hose from Jegs for my oil cooler and fuel lines. Don't remember the part number. But I've run lots of ethanol gas through them and no problem found.
One thing I did find that was incompatible was the capacitance fuel probe. It failed within one tank of mo-gas.