Have you read through all of Randy’s S-21 newsletters? I think many of your questions have been covered here. I can hit a few from memory, but the rest are on the site in the newsletters, specifications page or elsewhere. I believe everything I have seen thus far is 6061 T6. They have none from the factory and with 6061 a good case can be made that they don’t need any. Having said that, I am priming all of my internal structure as I like the looks of primed parts and for a little extra protection. I believe the only recommendation from RANS is to prime faying surfaces and dip any rivets with dissimilar metals (steel rivets into aluminum or aluminum rivets into steel parts). Don’t know for sure. I believe 180 is advertised for the 340 and 120 for the 912. Don’t know. Not sure anything has been published given the false start with the 915 due to the ridiculous initial Rotax intake temp limit. I would expect the 340 to be faster below about 7,000 and the 915 to begin to pull away above that.

@Peter Palmer Assembly Alert 191. They are on RANS web site and I provided a url in my first reply.

Have you checked AA191 to see if that is the problem? https://3bf21215-1086-4c74-9760-94816d14f2ef.filesusr.com/ugd/6e941e_bcdf696dab1b41a5afac740879e156e6.pdf

I never heard from RANS and did not want to wait so I just used my best judgement and reformed the ends of the ribs using a long drill and block of wood to tighten the radius and move the flanges closer together. Someone else posted that RANS suggested to them to just elongate the holes, but I really didn’t like that approach.

I posted what I did in the Facebook group. Not sure it was the right solution, but I think it will work. RANS clearly has a manufacturing issue here.

From Eddie Gill in the Facebook group: ”Matthew, you don't want them digging in the housing, go bigger hole size. We probably used smaller screws at one time and #20 cleared them.”

Thanks, Ryan. The misalignment is small, probably 10 thou or less, but definitely noticeable to the eye. I wanted to be sure this would not cause issues before drilling a bunch of holes!

Waiting on the reamer to arrive. I hope I can get to the one hinge on the rudder that is inside the leading edge skin. That may be a little tricky.

To close the loop on this. Another builder mentioned in the Facebook group that these are a good choice as an “oops” rivet for the AAPQ-41. And these are readily available from multiple sources.

Well, I haven’t found an oversized rivet option as yet. I looked for an AAPQ-51 which is the next diameter size up from -41, but it appears that size does not even exist. I found tables with -52, but the part thickness of 0.061 (according to my calipers) is slightly less than the minimum spec (0.062) for the -52. And I have yet to find a supplier than sells the -52. I see you carry -62s in your online store, but I hate to go that large as I don’t think the hole requires that much oversize. Any suggestions as to rivet suppliers I may not be aware of that sell a -52 or a -51 if such an animal exists?

Thanks, Ryan.

I am reading my August 2020 issue of Sport Aviation today and there happens to be a column on page 100 discussing AN hardware basics. It says that the normal installation is to have no washer under a bolt head and one washer under the nut. The rationale is that you need a washer only under the part being turned. Makes sense. The exceptions are places where the bolt must be torqued rather than the nut and cases where you need more than one washer (up to 3 are permitted) to accommodate a bolt where the grip is a little too long and the extra washers are needed to ensure the nut doesn’t bottom on the threads. I suspect AC 43.13 says the same, but I did not confirm that.

Stewart Systems Ekoprime. I plan to use their products for the exterior so I decided I might as well get familiar with them now and get my paint spraying equipment set up and get some practice with it in a less critical way. And this way I know I will have compatibility should some of the exterior products get on the parts I primed during assembly.

I ended up doing pretty much the same. I drilled the top hole first and then bolted the mount tube. I tried to clamp the bottom, but that powder coat is so slippery on the aluminum that it really didn’t stay in position well so my wife and I just held it as parallel to the spar as we could and drilled it. I used the #11 drill since that was in the table as you mentioned. I don’t think this is a critical part alignment-wise as it just holds the rudder horn and as long as it ends up close to horizontal I can’t see it being an issue. Now that I think of it, I don’t recall the text manual saying to install the rudder horn, but I assume it is done now since it is called out in the parts diagram. I’m a little cautious just starting out and probably got spoiled by taking the Sportair Van’s builder workshop as the Van’s manual pretty much called out every single step so when I see something “missing“ now I tend to check and recheck. I’m sure this fades as familiarity with the RANS manual style increases. I am complicating things by priming parts and that bit me yesterday when I was transferring drilling the ribs. The drill broke through a little faster than I expected and hit the cleco on the opposite side. This pushed the drill to the side and elongated the hole somewhat. It was the last hole at the rear edge of the rib so I don’t think it is of any structural consequence and it will be easily covered by the rivet. I will check AC 43.13, but I think it is fine to just rivet as is. Had the other side been riveted already, that would not have happened. Yes, just starting out. Picked up the kit July 13th and had to build a work table and now waiting on spray gun and related parts. I broke my leg in May right as I was getting my shop finalized. I got my compressed air system installed right before my accident, but did not get my work table built, storage shelves build, etc. so that has slowed my start a little. And I will be a slow builder as I am a perfectionist by nature and that always slows things down. 😁

I take it you are having cooling issues. Bummer.

That was my guess. Just curious if you heated the other side of a test piece with a torch to see what the material does when heated? I would have some concern that an engine fire might turn the bedliner into a toxic smoke cloud.

I must be missing some context here. Is the bed liner used on the fuselage side of the firewall for sound damping? Or is it on the engine side? The first post seems to be jumping off of some other information or post, but I have not come across it yet.

Did 4 prove to be enough? My wife likes to sew things so I think I will buy some birdshot and see if she can make some. I am just wondering how many are needed during the build?

Do you have a picture of your final fit?

I am looking forward to this answer also As I am just starting my rudder. I see qty 9 Of item #13 washers in the parts list and I count 9 #13s on the parts diagram, so I am also assuming there is no washer on the bolt on the top As that would require 10, but it does seem odd to have one everywhere else and not here.