Hey Andy. I'm out of town at a conference for work this week and just saw this video. Since you asked ... Here's what i did on those countersunk forward skin holes: 1. I used a #40 drill bit to put pilot holes in the forward ribs according to the predrilled holes in the forward skin, using silver clecos to hold everything in place. I also used a wooden fixture I made that matched the cross section of the wing to ensure the skin was pressed up against the rib when drilling. 2. Then I up-drilled with a 7/64" drill bit and used the wooden fixture while doing so to hold everything in place and make sure my holes were centered. I still used silver clecos, though they were a little loose. The 7/64" holes are not big enough for copper clecos, but that was by design. I wanted the holes to be smaller after dimpling stretched them than i would've had with a #31/#32. 3. Then I deburred all of the 7/64" holes in the forward skin and the forward ribs. 4. Then I dimpled all of the 7/64" holes using the Sonex "simple dimple die." This stretches the holes to a larger size. 5. Then i reassembled the forward skin using copper clecos (which fit about the same as copper clecos in a normal, non-dimpled hole drilled with a #30 drill bit). In my testing, if I used the #31 or #32 drill bit suggested by Sonex, the holes stretched a little more than I liked during dimpling - everything felt too loose in those tests. 6. Using the wooden fixture to hold everything in place one last time, i riveted the forward skin to the ribs with flush rivets. The 7/64" holes seemed to be a really good compromise from start to finish and I was very happy with how everything fit together. Lots of Sonexes have been built by the book and you probably won't have any issues with 3mm/#31/#32 holes. I just preferred the tighter tolerances of the 7/64" holes during final riveting. BTW, I really like your landing light fixtures. I might need to copy that. 🙂
Hi Dan, Ok, makes good sense….my copper Cleco’s after drilling with a 3mm did and didn’t fit, so just put in the minimal amount to hold the skin tight against the ribs. The holes are still smaller than if done with a # 30, so that is a good thing. You could or can if you stick to the 7/64 use a smaller nail in the dimple but need to be careful when squeezing the die so it does not off set the hole and give you a countersunk that is a bit off set. The correct nail supplied with my dimples was just to big for the 3mm hole so found a nail slightly smaller and on my test hole seemed to work. The duckworks lights are the best and highly recomend them.
I jumped in to your build about a month ago and I apologize that I am too lazy to go through previous videos for an answer. I noticed on other builds in the states, mostly RVs, that the builders had a pathological need to alodine or prime the internal components of the wings as well as the rest of the plane to protect from corrosion. Never thought that was needed, and priming would add weight. And add to the build time. What was your decision making process for not doing this? And, if I may, have you heard from Gavin? Not seen anything from him for ages. Thank you sir. Great instructional video log of your construction process and I like how you pause to get information from Sonex before you continue with inaccurate plans or to answer a question. This will be a well built and safe aircraft.
Hi Andrew, I think the short answer is, is that with RV’s it is made from a different grade of aluminum or at least the earlier ones were. The Sonex is made of 6061-T6 and is naturally resistant to corrosion. That said I have primed the mating surfaces only, well that is except the spar as it came factory made. Earlier Sonex’s were primed, as was with RV, and is a builder’s choice. There are some aircraft flying today, that were primed and have corrosion, others not primed and no signs of corrosion- its horses for courses. Gavin is doing good, I emailed him around 3 weeks ago and he sent me a picture of his cowl fully fitted, looks great. Thanks for watching and your kind words
My first (aborted) project was an RV4, and I built the tail in the 1990s. Like a lot of builders I did the full acid etch, alodine, and prime treatment. Took a lot of time, nasty chemicals, and additional cost. Fast forward to 2009, I was restoring a 1946 Cessna C140 which like the RVs was built out of alclad 2024-T3 aluminum. So after about 64 years that airplane, which was a cheap airplane of the day in 1946, it was still airworthy. With that said part of the restoration involved a lot of disassembly, cleaning of corrosion, and priming so it would go another 64-100 years. My conclusion is that anything I build I probably won't be flying in 64 years, but it would probably be fine with bare aluminum. So when you alodine & prime you are really doing it for someone else. The Sonex is 6061-T6 which is not as susceptible to corrosion as 2024-T3. So I primed nothing but a few parts I made out of some 7075 I had laying around.
I was wondering about Gavin a couple of weeks ago, too, and emailed him. Sounds like he just has a lot of other things going on, but he said he'd try to post something again soon. 🤞
Looks great Andy, you are flying right along.
Still a bit to go on the wing, all the wiring and tip, then its deburr and rivets
Looks good Andy! I remember cutting those scary holes.
Yes it was a bit overwhelming but got there in the end
Hey Andy. I'm out of town at a conference for work this week and just saw this video.
Since you asked ... Here's what i did on those countersunk forward skin holes:
1. I used a #40 drill bit to put pilot holes in the forward ribs according to the predrilled holes in the forward skin, using silver clecos to hold everything in place. I also used a wooden fixture I made that matched the cross section of the wing to ensure the skin was pressed up against the rib when drilling.
2. Then I up-drilled with a 7/64" drill bit and used the wooden fixture while doing so to hold everything in place and make sure my holes were centered. I still used silver clecos, though they were a little loose. The 7/64" holes are not big enough for copper clecos, but that was by design. I wanted the holes to be smaller after dimpling stretched them than i would've had with a #31/#32.
3. Then I deburred all of the 7/64" holes in the forward skin and the forward ribs.
4. Then I dimpled all of the 7/64" holes using the Sonex "simple dimple die." This stretches the holes to a larger size.
5. Then i reassembled the forward skin using copper clecos (which fit about the same as copper clecos in a normal, non-dimpled hole drilled with a #30 drill bit). In my testing, if I used the #31 or #32 drill bit suggested by Sonex, the holes stretched a little more than I liked during dimpling - everything felt too loose in those tests.
6. Using the wooden fixture to hold everything in place one last time, i riveted the forward skin to the ribs with flush rivets.
The 7/64" holes seemed to be a really good compromise from start to finish and I was very happy with how everything fit together.
Lots of Sonexes have been built by the book and you probably won't have any issues with 3mm/#31/#32 holes. I just preferred the tighter tolerances of the 7/64" holes during final riveting.
BTW, I really like your landing light fixtures. I might need to copy that. 🙂
Hi Dan,
Ok, makes good sense….my copper Cleco’s after drilling with a 3mm did and didn’t fit, so just put in the minimal amount to hold the skin tight against the ribs. The holes are still smaller than if done with a # 30, so that is a good thing. You could or can if you stick to the 7/64 use a smaller nail in the dimple but need to be careful when squeezing the die so it does not off set the hole and give you a countersunk that is a bit off set. The correct nail supplied with my dimples was just to big for the 3mm hole so found a nail slightly smaller and on my test hole seemed to work.
The duckworks lights are the best and highly recomend them.
I jumped in to your build about a month ago and I apologize that I am too lazy to go through previous videos for an answer. I noticed on other builds in the states, mostly RVs, that the builders had a pathological need to alodine or prime the internal components of the wings as well as the rest of the plane to protect from corrosion. Never thought that was needed, and priming would add weight. And add to the build time.
What was your decision making process for not doing this?
And, if I may, have you heard from Gavin? Not seen anything from him for ages.
Thank you sir. Great instructional video log of your construction process and I like how you pause to get information from Sonex before you continue with inaccurate plans or to answer a question. This will be a well built and safe aircraft.
Hi Andrew, I think the short answer is, is that with RV’s it is made from a different grade of aluminum or at least the earlier ones were. The Sonex is made of 6061-T6 and is naturally resistant to corrosion. That said I have primed the mating surfaces only, well that is except the spar as it came factory made. Earlier Sonex’s were primed, as was with RV, and is a builder’s choice. There are some aircraft flying today, that were primed and have corrosion, others not primed and no signs of corrosion- its horses for courses.
Gavin is doing good, I emailed him around 3 weeks ago and he sent me a picture of his cowl fully fitted, looks great.
Thanks for watching and your kind words
My first (aborted) project was an RV4, and I built the tail in the 1990s. Like a lot of builders I did the full acid etch, alodine, and prime treatment. Took a lot of time, nasty chemicals, and additional cost. Fast forward to 2009, I was restoring a 1946 Cessna C140 which like the RVs was built out of alclad 2024-T3 aluminum. So after about 64 years that airplane, which was a cheap airplane of the day in 1946, it was still airworthy. With that said part of the restoration involved a lot of disassembly, cleaning of corrosion, and priming so it would go another 64-100 years. My conclusion is that anything I build I probably won't be flying in 64 years, but it would probably be fine with bare aluminum. So when you alodine & prime you are really doing it for someone else. The Sonex is 6061-T6 which is not as susceptible to corrosion as 2024-T3. So I primed nothing but a few parts I made out of some 7075 I had laying around.
Hi Andrew, Bryan alsways has sound advice
I was wondering about Gavin a couple of weeks ago, too, and emailed him. Sounds like he just has a lot of other things going on, but he said he'd try to post something again soon. 🤞
Which ailerons are you going with Andy?
stock, so not aerobatic