SonexBuilders.net

Fellow builders,

This discussion forum is a wealth of information! We have thousands of posts, by thousands of users, and questions are asked and answered on a daily basis. There are good ideas, musings, complaining and socializing here, and it's great! But one thing that has always been hard is to sort out the very-best info, and then make it available for future builders. The new Lessons Learned area is an attempt to change that.

You all know the pattern....a new builder finds this site and asks a typical beginner question. Experienced users will often jump in an answer it, maybe for the 3rd, 4th, or 10th time. This helps the new builder, but it's tiring for the experienced one. Furthermore, sometimes the response to the beginners question is "use the search", but that can be difficult to hit on exactly the message thread that explains things. Even experienced users find searching difficult, and have to try various keywords or searching specific user's posts to find what they're looking for.

This is where the Lessons Learned archive comes in.

The Lessons Learned area of the forum is intended to be a repository of only the best info. Oftentimes this info takes some time to distill and develop, and percolates in the general discussion areas for some time while different aspects of the topic are considered back and forth. But eventually the discussion wraps up, a consensus is reached, or the thoughts are fully developed and expressed - it's just rarely been re-packaged into a tidy "nugget" of good info. What's been missing is a conclusion post that restates, summarizes, and captures the essence of the topic. Those are the posts that should go into an archive and be readily available to future builders.

What can we all do to help?

Every one of us can post a Lesson Learned or Best Practice! Think of something that you learned during your project - something that you'd wish you'd known at the onset, or that explains something that is a common area of confusion or error. Write it up and send it in. The submission doesn't have to be very long, and there's a suggested format that helps walk you thru the thought process.

How do I know what to write about?

Not everything is a lesson learned. Some things are great ideas, custom mods or unique things to your particular project - we want to hear about those, but maybe in the other discussion areas. Write up the topics that apply broadly to others and that will be helpful to everyone down the road. Not sure if your topics meets that standard? Post it in the general discussion as a possible idea, others will help hash it out, and then when you're certain you have the concept fully fleshed out write a new post for the lessons learned archive.

Every one of us has dozens of these items in our minds, sometimes without us even knowing it. It takes a little effort to reflect on your knowledge, spend a few minutes drawing it out and writing it down, and then share it, but the effort is so worth it. You'll be contributing to a growing body of knowledge that will help others, and the self-reflection process helps you better understand your own experiences.

I challenge everyone to contribute just one topic. With that, we'll be off to a fantastic start!

Jeff

Jeff,

After reading your message, I did a little looking on the phpBB site to see what other features are available.

I noticed that while it isn't native, there is an extension for the phpBB that allows the "Best Answer" to be marked.

This extension does not modify the core files of the phpBB, so there is little to no risk in trying it out. Of course, Chris would need to implement it.

There may be a better extension, but I only looked for about 5 minutes.

Here is a link to a discussion about it:
https://www.phpbb.com/community/viewtop ... &t=2368876

Paul,

A "best answer" to identify good info would help highlight useful information when searching later, but I'm not certain this would be enough. Unless that post was especially well thought out it may not be complete, as-is. I'm suggesting that after all the discussion is finished, we consolidate the key points into a single comprehensive post. phpBB add-ons might be worth considering anyway, though.

Let me share a bit more of my thinking on this by way of an example.

A user wondering what size hole to drill for a CCC-42 rivet might search for "flush rivet", "hole size", "countersunk" or "dimple". These keywords would generate hundreds of results. There's a good answer in there somewhere, but it takes some work to dig it out. Similarly, the recent post about the ideal drill bit size for an AN525 screw (viewtopic.php?f=3&t=5454) has 9 posts, and a related post wondering about getting tight fit holes for the wing mounting blocks (viewtopic.php?f=21&t=357) has 46. These two threads are really trying to get at the same underlying question: "How does a builder create a 'tight fit' hole when the plans instruct it?". What is needed is a Best Practice summary post that lays out proven techniques with specific details to create tight fit holes called out in various places. This would then be archived in the Lessons Learned area for future builders to research.

Having just gone thru that example, I'm sure there are a hundred builders on this site that can generate that post, but none exists yet. We need to capture that best practice, and others like it.

Jeff

To keep this discussion alive and moving forward, I have a question to the group at large. What topics do you think we should include in the archive? What things do you wish you knew early on that we should share with others just starting out? What recurring questions or posts seem to pop up on a regular basis?

Post your suggestions, ideas or wants/desires, and let's brainstorm some possible Lessons Learned posts.

Jeff

I believe we should assist builders of legacy model Sonex’s in understanding they may need to be more aggressive in grinding the elevator horn than what the plans state. It may be required to grind farther into the weld than anticipated. I know this freaked me (and others) out when there is a caution not to do so.

I’d also add the wheel pant brackets for taildraggers. Expect to have to make modifications.

Jeff,

I had problems/frustration in the tail section on the Onex build. As an example ref. http://sonexbuilders.net/viewtopic.php?f=5&t=5461. There were other clearance and rigging issues I encountered, none of them major, but collectively they were a bit frustrating.

The frustrating was amplified because after the turtle deck is on and the plane is on saw horses these little problems have to be dealt with while crawling around on your knees with your head stuck up in the tail and a light bar strapped to the ball cap.

Sitting here at the keyboard I'm not sure it's practical, but a build sequence that allowed elevator and rudder rigging before the turtle deck and turtle deck formers are in the way would have reduced my frustration.

If other Onex builders followed a build sequence that made tail rigging easier I wish they would chime in (Dirk you out there?).

Thanks

The following has a bit of explanation, but a longer writeup on several of the points could be useful.

Of the top of my head, I wish I would have known:

1. or realized how difficult it is to work under/behind the panel. Although I made the center of my panel removable like Jeff did, I don' use that panel because it's just not big enough. I'd perhaps make my entire panel hinge down.
2. In addition to the first item, I would have ran a channel for all, or most of the panel wiring on the passenger side even if I had to add a few rivets in the fuselage to support it. Yes the wires would be longer, but they would have good support instead of just being zip tied to the fuel tank straps.
3. I would have enlarge the full flap slot so the flap handle wouldn't get jammed. This part was fabricated by Sonex, and caused me to have to fly about 20 miles with full flaps.
4. I would definitely still use the red cube fuel flow sensor. It really helped with the initial WOT tuning of the engine. I also use it and EGTs to determine % engine power level during cruise.
5. I would have drilled the wing attach blocks to the final size on a drill press while the spars are clamped together. I used a step drill with the competed wings clamped together outside the fuselage, and this also worked well, but required a special step drill. I think the whole thing could be done without a step drill if drill bushings were used when finally drilling the verticals as I did.
6. The screw that holds the wheel pant to the axle bottomed out, so there wasn't clamping force. This and a very poor landing resulted in the wheelpant catching on the tire, and almost causing me to nose over. I've since reinforced that area, and used washers as needed.
7. Controversial one is using loctite to hole the titanium legs in the axle sleeve, and the engine mount. Kerry had suggested I not do it, as removing them would be very difficult. I spent a lot of effort making sure that the holes I drilled were a nice snug fit on the 1/4" bolts. The axle sleeves still began to oval after a while. I ended up changing to a 5/16 bolt, and used leftover green loctite 629 (from Jab prop hub bolts) on both ends. I figure if I ever have to remove them, it's be because something major happened anyway. I'd remove the engine mount from the plane, and heat the loctite until the legs came loose.
8. I would have used the resistive spark plugs from the beginning. They cut down on electrical noise tremendously.
9. I wish I wouldn't have spent time making a heat muff for the exhaust pipe for cabin heat. Getting warm air from the oil cooler works just fine, and there is less risk of CO poisoning.
10. Speaking of CO. I with I would have know I was going to gave such an issue with it. I've made sealing modifications to the firewall, including the fuel fill area. I beaded my exhaust slip fit joint, then even brazed it (but couldn't get it brazed in the middle so it still leaked). In the end, sealing the firewall/fuel fill area, the tail area, and clamping an extension to only the front of the exhaust pipe to create a low pressure area (to "pull" out the exhaust) is what it took to solve the problem.
11. Occasionally when I'm descending with an almost full tank, I'll start to smell fuel. I'm thinking it's leaking out the fuel vent. Most of the time it's not an issue, but occasionally it can be really annoying. maybe someone has the solution to this.
12. When positioning the horizonal stabilizer to the fuselage, make sure that the elevator control horn isn't going to contact the vertical stabilizer. I measured mine several times, and I think the holes on my horizontal stabilizer were already drilled by Sonex. I wanted to make sure there was enough hole to edge distance for the bolt holes, so my horizontal stabilizer ended up being about 1/8" too far back. I ended up having to do a lot of grinding on the elevator control horn to keep it from rubbing. Don't make this mistake, clamp it all on first and verify before drilling.

I'll update this if I have any more random thoughts.

Hey Jeff,

More (random) thoughts.

Why are we doing this? I'll give my answers. We are doing this to help the Sonex community.

The Sonex community has two major components, "Sonex LLC" and "Sonex builders and pilots". Each without the other dies, or is at least severely hobbled. So, in the end analysis this effort needs to help whole Sonex community.

Kerry wrote:

What's needed is everyone supporting everyone and the recognition that this is homebuilding.

So how would this be best accomplished? How could the "Sonex builders and pilots" side of the equation help?

In my wildest dreams all of the difficulties, issues, problems, build sequences, oversights, ..., would be collected into a model specific article that could be referenced before a new builder starts the build. I think a well written Onex article would be no more than 10 pages.?.? Presumably this would decrease builder frustration, increase completion rates, and have an overall positive impact on the company and the builder. Come to think of it, we don't have a real builder manual, do we :-) Just something to consider after the information is collected.

It would also be nice to put the polishing to bed. Best methods, best practices, best products, ...

Robbie wrote:

It may be required to grind farther into the weld than anticipated. I know this freaked me (and others) out when there is a caution not to do so.

This is definitely the type of thing that needs to be addressed. This is the sort of thing that will stop some builders dead in their tracks. It's like all the hoopla about trimming cooling fins on the Jabiru oil sump in the old days.

Thanks

Paul,

This is an excellent list! Every point you listed would make a valuable addition to the archive. Some are pretty self-evident and don't need much elaboration (e.g. "Plan for panel access"), but others might benefit from a more thorough write-up (e.g. elevator joiner interference). I'm compiling a running topic list that I hope will generate posts on each one. I plan on writing up some of these myself, but I don't want to give the impression that this is all just me. This is a community effort, and everyone should contribute.

Jeff

Just a comment from someone who would be looking at your site for info.

You guys have been working on your planes and have learned more than you know. Don't make the mistake of under valuing what you know. Things that seem so intuitively obvious after you have spent time learning are not so obvious to those of us without the experience. I'm a "casual" builder with everything to learn and having a single site to turn to for information would be wonderful. Looking up the answer to a dumb question is much easier than having to ask the dumb question on the forum. I search thru these threads regularly and occasional ask about things I can't figure out. There are probably lots of us who really appreciate your experience without saying thanks as often as we should.