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« Last post by Kamcoman77 on January 12, 2026, 11:01:49 AM »
Looks like everything is working out just fine.
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« Last post by Isotope on January 12, 2026, 08:27:35 AM »
Also to add to the above post i added 1/8 ply doublers 1/2" wide to the web butt joints on front surface for extra piece of mind. Just the first two butt joints not the outboard one 10" from spar tip.
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« Last post by Isotope on January 11, 2026, 09:43:10 PM »
Little update. Almost finished with second front spar minus the strut and wing attach doublers. The way i did the web splices is where ever a 4' ply stopped is where i put a 3/4x1/2" upright regardless of where the 3/4x1/4's were. This added 3 extra uprights of which were 3/4x1/2. That is how i interpreted the plans. Another thing this did was prevent me from drilling 2 of the 18 lighting holes where it showed on the plans. I also didnt not want to put a hole to close to a web splice. So for this i drilled the extra 2 holes in the next section closer to the strut brace. See pics. I also added 4 more 1.5" lighting holes on the most outboard section. After researching some Minimax and Airbike spars they dont even have a web on the most outer section. 4x1.5" holes is equal to 1x 3" hole in weight. I also added a 1/8" ply doubler to the scarf joint i made in the upper cap strip within 2' of the outboard end. Im sure it would be fine but this gives me some extra comfort as that was my first time scarfing a spar of a full scale aircraft that i will be piloting 
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« Last post by Kamcoman77 on January 10, 2026, 10:41:54 PM »
I don't guess the 5/8" below the front & rear spar caps is critical for structure. My only issue was the rear strut was very close to the fabric compared to the front one, so I adjusted the mounting holes to compensate. I have no idea if that is a known error but did not want my rear strut pushed up against the fabric. I put lightening holes where you have the red circles. I put the little 0.8mm ply gussets on all my spars. Added about 8 ounces. The reason for those gussets was some of the vertical upright joints broke when I dropped one of the spars on my concrete floor before I had any ply webbing on it. I figured a gusset on one side and the 3mm ply web on the other made those joints super strong. If I build another XL, I will leave them off. I'm helping a buddy build an XL and we are not using those gussets (photo). It did require sawing notches in the front of the ribs. Turned out it was a one bandsaw width cut.
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« Last post by Isotope on January 10, 2026, 09:54:18 PM »
Nice catch but.. I ordered Les's prefabbed mounting bracket kit with holes already drilled.. i dont believe there drilled to this specific dimension. Is this a known error and crucial to fix?
Question i have. The way i installed the 1/2" uprights for web splicing i just put them where ever a 4' piece of ply would land. In that case a couple of them ended up right where a lighting hole would be so i am short 2 lighting holes. Could i drill the 2 holes in the next section over closer to the strut bracket? but dont want compromise this area. What do you think, see attached for where i didnt drill a hole with an "x" and where im proposing to drill a hole with the red circle.
PS: what kind of weight penalty did you add for adding those gussets to the uprights? Did u add them to all uprights? See attached.
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« Last post by Kamcoman77 on January 10, 2026, 09:10:47 PM »
In your post showing Page 35, I just remembered a "gotcha". The strut fitting dimensions for the front spar are correct, but the rear spar is showing the same distance below the spar cap for the hole that the strut bolt goes through. In my opinion this is a mistake. The rear spar cap is 1/4" from the bottom fabric of the wing while the front spar cap is even with the fabric. I think you should add 1/4" to the 5/8" shown for the rear spar bolt hole. This will place the bolt hole for the strut attach 5/8" below the fabric.
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« Last post by rv7charlie on January 10, 2026, 02:11:14 PM »
Charlie,
I am going out on a limb here to say that I am likely the only one who can answer your question with any experience: I have a CNC router, with a tube cutter, of which I use to cut aircraft tubes. I have written specialized software to perform the coping calculations which result in CNC files. And yes, I am the guy who has cut the tubes for the current builds of Barnaby Wainfan's Facetmobile. Those details are here:
https://worktablecnc.us/projects/facetmobile.html
I have also built a Legal Eagle the traditional way: With two angle grinders, one with a cut-off wheel and one with a grinding wheel, I have cut, ground, ground, ground, and ground until the tubes are all coped perfectly together. I did the welding using TIG, and any gaps left I had to bridge with extra filler. Those details are here:
https://worktablecnc.us/projects/legaleagle.html
---
If I had to build a second Legal Eagle...
I would probably use the CNC. It would take more time. I am a builder, that does not bother me. I enjoy building, solving problems, being creative, and ending up with a product which reflects the very best I can do.
If I needed to get it done quickly...
I would cut it by hand just like I did it before, and then blast it with a MIG welder.
---
* There is space enough in this community that either way is the correct way. You do you. *
---
I do have a few additional comments:
+ If you already have a RV-7, then you already have an aircraft with a second seat that most of the time will be empty. If you are looking for a simple after-dinner flying machine then please reconsider the single-seat Legal Eagle. It will be an ultralight, no registration, lots of flying examples, easy-peasy. I have a lot of friends which are RV builders/pilots. A common mantra with those guys is More-Is-Better. Legal Eagle = Less-Is-Better.
+ I previously looked at the VR3 Engineering requirements (for the rest of the group VR3 Engineering is a Canadian company which provides CNC cut tube kits, and they do not exclude aircraft). You can either simply buy one of their kits, or you can send them your own files. However, creating your own files is no small task: You have to take every tube, drawn and coped in 3D, then slit the 3D tube, flatten it, and provide a 2D pattern. I use CAD for a living; this is a mountain of work. Whoever did all of this originally for the Legal Eagle patterns at VR3 deserves a big hug.
+ No, I do not provide CNC services with my router. I only helped out a few of the guys at my local EAA chapter, and Barnaby is now one of them. The time I have spent on their projects I could have completed another aircraft of my own. I have a list of projects I would like to do which exceeds my lifetime, and becoming a tube kit manufacturer is not one of them.
Respectfully,
Robert (BobbyBreadwinner)
Oregon, USA
https://worktablecnc.us
Hi Robert, First, sincere apologies for not responding until now. I somehow lost track of my own thread here; apparently I haven't set up email notifications for posts to threads I'm supposed to be following. I love what Barnaby's been doing with low aspect ratio stuff. I helped kill the grass around the Facetmobile at OSH, and I've been wishing for 2 seat plans ever since. I've prowled around your website in the past; truly amazing stuff! Your advice on hacksaw/file vs cnc matches my neighbor's; he's built several tube/fabric a/c & talks about knocking out a fuselage in a week. ;-) I just need to order the plans and get on with it. Charlie edit: On coping the tubes accurately, I learned the importance when I built a couple of hangar doors from 6" aluminum irrigation tubing. The 1st door was built with just gussets, and it's a bit of a floppy mess. The 2nd door I used printed templates to cut accurate fish mouths, and left material so I could bend tabs. Used sheet metal screws to effectively 'weld' the fish mouths to the adjacent tubes, and ended up with a much more rigid and strong door, with no gussets at all.
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« Last post by Isotope on January 10, 2026, 07:21:53 AM »
Again prolly thinking to much into it but next question lol. Page 34 on the spar section is shows 9, 3" holes driller in the 3 most outboard section's of the spar. Then on page A it shows 12 holes drilled all the way up next to the strut bace section? What is common conciseness here? It makes since on page 34 him wanting to stay away from drilling holes near a stress point like the spar attachment. I suspect this would be a few ounces saved though if they were drilled out all the way up too it like on the overall view on page A.
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« Last post by Kamcoman77 on January 09, 2026, 01:09:09 PM »
Front wing spars get plywood web on front face and rear spars get plywood web on rear face. I'm not sure I understand your question about doublers but my left wing photo shows how I did mine. I ran the grain direction of the outer ply layers spanwise.
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« Last post by Brock on January 09, 2026, 10:00:37 AM »
I am learning lots from your posts/pictures/questions. One of these days it there will be nothing left to do on the airframe and I'll have to start on the wings. Keep posting.
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