Johns LSA Build

[jaredyates]

Hi Stinger. I was thinking about how the RV4 aileron is designed, it has a minimal frame with stiffeners riveted to the one piece skins and of course with the half inch water pipes riveted in the nose as counter weights. Its not some thing I planning to do but it is something interesting to think about. I wonder if it would be as light at the original design but have the durability of a metal skin vs a fabric skin? What do you think?

I'd say it is rare when Bob leaves much meat on the bone when it comes to weight reduction opportunity, and that he probably worked it out. This would be a great question for him sometime sitting under the wing at an airshow! He seems to love talking about this kind of stuff.

[davzLSA]

I look forward to that opportunity some day Jared.

[stinger]

Dave, making changes or mods to fit your personal needs is great. However flight controls are a different animal one would have to consider flutter and thus loss of control . I made a lot of changes but not with controls such as fuel gages instead of the sight tube , three stringers on the fuselage back, an additional baggage compartment along with a door, I moved the engine forward 1 1/2 inches , a lot of fairings, rear seat brake. My LSA flies great. It's heavy at 900lbs, I like it, I weigh 155lb My friends plane sets at 860lb but he is 265,so there . Good luck Stinger

[davzLSA]

Hey John thanks for documenting your build here, i know it will be invaluable when i start my wing build. I hope my fuse build will be of value to you.

[johnb]

You're welcome. It's been slow going this spring. I'm working on rear spars now. Have all the parts fabricated and drilled up. Starting to debur and prep for priming. I'll try to get some pictures soon.

[davzLSA]

Ill be interested to see how you do your cap stripes.

[johnb]

Rear spar cap strips on the LSA are only 1/16 thick and the longest is just over 3 feet. For these, I purchased a 2'x4' sheet of material. This material can be used for cap strips and other spar components. For rear spar cap strips, I cut strips from the sheet with a jig saw and metal cutting blade, belt sanded to final width, and scotchbrite to clean up the edge. I haven't purchased cap strip material for main spars yet.

[bergy]

When making the cap strips for my Patrol I was amazed at how easy it was to distort a long strip of aluminum by the cutting process. The strips were initially cut from full sheets of aluminum by a friend who I think used his hand power-saw. The cuts were crude and work-hardened the edges of the cuts; the strips curled off in random directions. I clamped each strip in turn between two wooden 2x10s using some galvanized steel flashing material as a straight edge. I tried using a router to true up both sides but even the small router-cuts still left internal stresses in the aluminum and the strips would curve. I resorted to removing all router-induced stresses by running an old carpenter's wood plane down each side of the cap-strips, removing all signs of the router cut, and they all came out nice and straight and stress-free.

[davzLSA]

a vixen file works good for that too

[Papa Foxtrot]

Aircraft Spruce stocks the 1/8" x 1" 2024 for the main spar cap strips. Fortunately, the rear spar caps are fairly short. If you're patient, you can cut them with an Olfa knife. If you're not, try to find a local sheet metal shop with a shear. If you have access to a brake, you can try this technique - https://www.youtube.com/watch?v=gIk3M7DMZpY

[johnb]

Hi guys. It's been too long since I posted anything, so I thought I'd give an update. My rear spars are now complete. Main spars are in work. As discussed above, I cut rear spar cap strips from .063 sheet. It worked out well. I purchased main spar cap material from A/C Spruce. For most of the spar root and splice fittings, I made templates in MDF and used a flush cut router to cut them out. It worked well to make multiple identical parts. I'm currently drilling main spars parts. This weekend I finished drilling cap strips to the spar channels. So far, spars have gone together well. I'll try to do better on updates.

Here are a few pictures.

- John ​ ​ ​ ​

[johnb]

Hi guys, I've been to busy working and not posting anything, but as of last week, wing spars are complete. Lots of parts to fabricate and fit together, but the came out well. I used my homemade brake for the spar channels and purchased cap strip material from A/C Spruce. Next stop, wing assembly. IMG_20200720_101129775.jpg

[davzLSA]

Those spars look great John. I cant wait to get to that stage of my construction. As of now ATT is trying to work me to death and I need to finish my new shop extension. I am encouraged by your progress.

[Frank]

Great progress - from complete ribs to complete spars in a few months!

[johnb]

A couple of weeks ago, Bryan Walstrom from Experimental Aircraft Channel filmed a video on my project. Rob Caldwell was there as well. It was fun to visit with these guys and share my build. Hope you enjoy this.

[johnb]

Lately, I've been working on wing assembly. I built a jig and stated drilling up main ribs. The stand in the middle is to prevent the spars from sagging during the initial fit up.

[rodsmith]

I watched the video, I am so impressed with your work, beautiful parts!

[Frank]

Hey great video John! Thanks, and thanks to Bryan of EAC.
(At some point I need to acknowledge all the online video and article authors)
I've seen homebuilt 8' brakes described and will certainly consider that option, if only because it looks like fun.
And thanks for the tip on using a paper cutter as shear!
Good stuff!