Zenith CH 750 STOL Build Log

Received and Read Through FlyCorvair Manuals

Sun, 16 Aug 2026 06:33:55 +0000

The FlyCorvair manuals I ordered arrived and I read through them. It's going to take a bit of effort and additional research to develop task and parts lists from the format. But I now have a better idea of the scope of work involved.

Fabricated radius shoe for metal brake

Sun, 16 Aug 2026 04:59:27 +0000

Based on the earlier metal brake research, I tried using 2 3"x24" strips of .032" 3003 aluminum to try to create a fully supported 3.2mm radius for a 24" metal brake and it worked successfully. I bend one piece over the other adjusting the finger setback slightly for each bend.

I used a quarter of a sheet of 12"x48"x.032" of 3003 aluminum leaving enough for a future 48" brake shoe, and possibly a ~12" shoe for a hydraulic press brake (which would use more layers to get to 6.4mm radius for thicker 6061-T6 bends).

Printed more radiuses and tried shaping rivet gun nose

Tue, 11 Aug 2026 06:01:47 +0000

I printed more radiuses including two color coded ones that match the ones that most parts in the plans have to allow for adequate bending without cracking of 6061-T6. Planning to always check my form block round-overs and brake bends with these on hand going forward.

I attempted to use the techniques several YouTubers show for shaping the rivet gun head in the manner that Zenith uses for their assembly methods. I thought the A5 attempt turned out ok, until on closer inspection I realized the concave bit I had was off center and setting rivet heads unevenly. Even if I'd managed to get it machined centered, I think this is terrible advice to suggest people do considering 1. Zenith doesn't specify the radius for the round out in their construction guide. And 2. Zenith offers to do this on your tool's rivet heads for free.

Sourcing, research, and 3D printed radius gauges

Tue, 11 Aug 2026 05:49:20 +0000

Got referrals to places in Tucson that have long sheet metal brakes, and learned of a better online source for 6061-T6 at airparts.com than Wicks or Aircraft Spruce.

Placed a small tools and materials order with airparts.com including .04 sheet 6061 which they ship rolled (and which other online sources do not).

Exhaustively researched options for precisely bending radiused edges on 6061 .016-.032 and landed on making curved shims with non-tempered aluminum as the most cost effective and least time consuming choice. Going to do a proof of concept on a 24" brake using 3003 aluminum. I'm anticipating that 2 layers of .032" (bent in succession around each other) to max angle of brake will create a nice radius when combined in two layers under the brake fingers. If that works, I'll buy an inexpensive 48" to use that with as I'm not very motivated to build one.

Ordered manuals from flycorvair.net and researched local Corvair clubs and parts sources.

Watched videos on scratch building Zenith 750 stabilizer.

3d printed some mm radius gauges to verify the wooden shaping forms' round overs are adequate. I found that most of the ones I've made with a 1/8" round over router bit are not enough based on what's specified in the plans, so I ordered a 5/32" round over bit.

Attended first EAA Chapter Meeting

Sun, 09 Aug 2026 05:50:44 +0000

Drove out to Ryan airfield to attend my first EAA chapter meeting and got some great advice from an experienced plan builder named Eric.

Finished front rudder rib form and 51mm flange die

Sun, 09 Aug 2026 05:46:11 +0000

The female part of the flange die ended up needing a different XY dimension adjustment coefficient than the male one, but after the second try it's also well within tolerance and the fit is perfect between the two.

I was able to finish the form block for the front rudder rib using a spindle sander with an adjustable bed angle that I bought from someone on craigslist Thursday evening.

Progress fabricating rudder forms

Sat, 08 Aug 2026 05:43:11 +0000

Made progress fabricating rudder rib forms after cutting the front rib template blank last night. Need to start using a taper jig on the table saw to make things easier with fabricating forms for straight edged ribs.

Received my order from Zenith that included the premade top rudder rib, some Cortec primer, and A4 and A5 Zenith rivets.

Also 3D printed a flange die after some trial and error with determining the amount to adjust the STL file's X and Y dimensions to account for PETG shrinkage during printing. The inner piece is now nicely in tolerance. I'll see if the same scaling coefficient works with the outer piece of the flange die. Then I'll make the larger two sizes that Zenith plans use. I'm using a 85% infill and 4 layers of wall thickness in my slicer.

Collecting more tools and drafted rudder rib

Thu, 06 Aug 2026 05:41:18 +0000

Drafted front rudder rib form on metric graph paper. Planning to glue to plywood and shape into to the pattern template piece to cut other the shaping forms from either this evening or tomorrow evening. Collected more tools. Placed sheet metal order to cover most of tail section assembly. Rivets arriving tomorrow from Zenith. Once those arrive I can machine the rivet air tool heads for the rivet head shaping approach Zenith uses.

Air drill reassembled and tested

Fri, 31 Jul 2026 05:38:57 +0000

Received a tool order

Thu, 30 Jul 2026 05:34:41 +0000

Received tools ordered from Aircraft Tool Supply

Drill restoration progress and received plans

Wed, 29 Jul 2026 05:33:12 +0000

Pressed replacement bearing onto drill vane cylinder with fabricated replacement gasket, and received aircraft plans from Zenith.

Drill restoration progress

Tue, 28 Jul 2026 05:31:44 +0000

Laser cut replacement gasket and applied cold bluing to exterior steel parts.

Restoring air drill

Fri, 24 Jul 2026 05:30:29 +0000

Restoring air drill while waiting for aircraft plans to arrive. Findings on disassembly: 4 of 5 vanes stuck due to corrosion, 1 of 4 bearings need replacing, paper gasket has a tear, and a badly in need of cleaning, corrosion removal, and lubrication inside.

Sourced some tools

Thu, 23 Jul 2026 05:26:13 +0000

Sourced an air drill, a Scotch-Brite bench grinder wheel (MU-WL), and some small red and green abrasive flap discs at Tucson Tool Shop.