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Nov 23, 2017, 02:41 PM
ʇsol
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Build Log

Gentle Lady build


Scratch building a Gentle Lady. Trying to make it a "quick build" project over Thanksgiving. We'll see!

The plans are floating around the internet but I have an original RCM set and a set from a kit around here somewhere. The .pdf-based plans are kind of rough, but dimensionally fairly good and usable for creating parts. As long as everything fits it isn't overly critical anyway.

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Day one & two, weekend prior to Thanksgiving - worked on drawing up the parts in CorelDraw. I already did the basic rib layout a while back in Profili/Wing Dev but tweaked them for the build.

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Latest blog entry: Sagitta 600 build 2018
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Nov 23, 2017, 02:43 PM
ʇsol
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Gentle Lady build - Day 3


Day 3:

Spent the evening of Day 3 going over the CorelDraw drawings again and setting the drawings up in CAM (Cut2D).
Latest blog entry: Sagitta 600 build 2018
Nov 23, 2017, 02:53 PM
ʇsol
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Gentle Lady Build - Day 4


Day 4, Tuesday:

Triple-checked the drawings and CAM work then starte cutting the fuselage parts.

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I decided to design the fuselage sides, top, and bottom - along with the formers - to fit together with tabs and slots/pockets so it will be self-aligning. At least that's the idea. Presumably to keep the box small and costs down, the kit used short pieces of balsa spliced together. Due to my smallish CNC machine I'm forced into the same situation. I used a splice I came up with in my Sagitta build made from several gentle oval shapes and two shoulders. The splice tends to be self-aligning and the lack of many sharp corners makes it easy to CNC.
Latest blog entry: Sagitta 600 build 2018
Nov 23, 2017, 03:06 PM
ʇsol
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Gentle Lady Build - Day 5


Day 5, Wednesday:

Assembled the fuselage bottom ply, middle, and cross-grain rear section. During the parts design I added several centering marks along the center-line. While assembling the parts I used a straight-edge to make sure everything was straight along the center-line.

Also assembled the fuselage sides. No alignment marks here, but it isn't overly critical. I lined everything up the best I could on the first side, then glued the second side up over top of the first so they're the same.

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While those were drying I went back to cutting the former parts. That's where I found my first major mistake: the pockets I made in the fuselage side doublers were based on a 1/16" doubler and tripler. They should have been based on a 1/8" doubler and 1/16" tripler! Made a minor modification in CAM to shave the tabs on the 1/8" doublers to 1/16". They're more for convenience than anything else, no biggie as long as everything lines up properly.

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Later that evening I checked the fit of the fuselage side doublers to the formers, sides, and nose former F1. Everything looked good, so I laminated the sides and doublers with thick CA.

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Checking the fit of the formers to the sides. Not too bad. They'll glue up ok:

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Back to the wing - trying to get as many parts done as I can - laid up the spar braces in CorelDraw and cut them out of 1/8" ply:

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Latest blog entry: Sagitta 600 build 2018
Nov 23, 2017, 03:12 PM
ʇsol
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Gentle Lady Build - Day 6


Day 6, Thursday:

Set up all the ribs onto 3" 3/32" sheets in Cut2D - 8 sheets total. Spent time CNCing the rib sheets in between cooking Thanksgiving stuff:

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Added doublers to the rear-fuselage:

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Last edited by vulturetec; Nov 23, 2017 at 03:53 PM.
Nov 23, 2017, 09:45 PM
ʇsol
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Gentle Lady Build - Day 6 Continued


Added the 1/8"-square longerons to the fuselage sides. After Thanksgiving dinner temporarily added the bottom and nose-former, then glued in the two main formers using the tabs and slots in the bottom plate(s) to force it into alignment.

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Latest blog entry: Sagitta 600 build 2018
Nov 24, 2017, 06:15 PM
ʇsol
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Day 7, Friday


Getting there:

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Need to add the rear-most sheeting, cross-grain. The curvy splice was completely unnecessary here. A wide tab for alignment would have been a better choice. Lesson learned.

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Everything fits though. The cross-grain sheeting is fragile in the splice area so I didn't force the issue when test fitting it (shown here). With glue it slid together better, but I still needed to use masking tape to pull it as tight as I could.

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Also didn't force the slots onto the alignment tabs, but they fit (test fitting shown below). With glue it all fell together pretty well.

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Latest blog entry: Sagitta 600 build 2018
Nov 25, 2017, 12:12 PM
ʇsol
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Gentle Lady Build Day 8


Day 8 - Saturday

Actually started one of these Friday evening and the second one early Saturday; I'm laminating a hard balsa cap to the top of the inboard section of the main spar, similar to an option called for in the kit's instruction book. I precut the ribs to account for the additional spar material so I'm doing this step ahead of time with 30-minute epoxy:



Then it was time to scrounge around for trailing-edge stock. Sure I've got some, right? Yeah right. Except it's 1/4" and not 3/16". Not a big deal, I'll just recess the ribs a little more to compensate. That turned out to be a pretty good fit and didn't really change much.

I debated how to deal with slotting the trailing edges for the ribs. Doesn't take a genius to figure out how to cut some slots with a jigsaw or bandsaw, but ultimately I decided to go back to the CNC machine for it. I already had the wing layout I made in DevWing so I spent 15ish minutes in CorelDraw creating the correct size slots in the appropriate locations based on the DevWing layout. Set up diagonally I have enough working space to machine the inboard sections. Cutting the slots only took a few minutes and they're precisely where they should be - and fit nicely as well:



Rather than get my plans out I'm going to try to do this plans-free by transferring the rib locations to the two spars from the TE part I just machined:



After cleaning up the ribs I found they were a really tight fit to the spars but not unmanageable. They're so tight I'm not sure traditional glues are going to be easy to use, I might end up using CA with a light bead of PVA or duco around them at the spar, with traditional wood glue on the TE.

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Latest blog entry: Sagitta 600 build 2018
Nov 25, 2017, 02:03 PM
Registered User
I probably missed it somewhere, but wondering what CNC machine you have?

Charlie
Nov 25, 2017, 04:40 PM
ʇsol
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Quote:
Originally Posted by cpc625
I probably missed it somewhere, but wondering what CNC machine you have?

Charlie
No, I haven't mentioned it. I'm using a Shapeoko 3, early 2016 version.
Latest blog entry: Sagitta 600 build 2018
Nov 25, 2017, 05:51 PM
ʇsol
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Day 8 - continued

...back to earlier - the basic wing put together without glue:


Spent quite a while looking for the right leading edge material and - nope, don't have it. 5/16"x3/8" is called for and all I could scrounge was 1/4"x3/8". Could have blunted the leading edge a little but...ended up laminating some 1/16" sheet to one side of the material I had. Wasted time but it's done.

With that settled, back to gluing things up. I carefully cut the bottom sheeting with a 90 angle between the TE and outboard edge and used it to make sure the ribs weren't skewed. Ran a couple drops of thin CA around each rib joint then added a bead of duco around each. The joints are so tight I'm not sure how I could have used other glues without scraping it all away in the process.

Backing up a little, I cut the dihedral angle on the spar with the CNC machine. Only took a couple of minutes and the results were really good.

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With everything glued up solid I test-fit the three center dihedral braces. Decent fit!

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Now I need to get to the other side and the tips. Still need to cut the outboard ribs at the poly break too.
Latest blog entry: Sagitta 600 build 2018
Nov 26, 2017, 06:01 AM
Registered User
Thanks for the info. If you have a moment, PM me. I have a few questions about your setup

Thanks

Charlie
Nov 26, 2017, 06:47 PM
ʇsol
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Gentle Lady Build Day 9


Day 9 - Sunday

Built the inboard left wing panel. Had to build the leading edge and cut the spar like I did the other side. Would have been a lot more convenient to build little things like that together, ahead of time. Had to scrounge for the rear spar. Also had to scrounge for the 1/16" lower sheeting! Had almost enough then had to switch to some ~2mm stuff sanded down to match. Time wasted!

Latest blog entry: Sagitta 600 build 2018
Nov 26, 2017, 07:39 PM
ʇsol
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Test fit the two wing halves. Need to tweak it a little to close a gap on the lower sheeting, but it's really close. Everything fits and the dihedral seems right on without any fiddling. The two TE pieces aren't quite the same size apparently (and verified).



...also spent time laying out the slots for the outboard wing panels. Should be easy to set up and cut tomorrow.
Latest blog entry: Sagitta 600 build 2018
Nov 28, 2017, 08:42 PM
ʇsol
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Gentle Lady Build Day 10, Monday


Cut some more parts. Also ended up looking over the fuselage and decided I could do better. It's straight as an arrow along the center-line but with a twist I just don't like. It's salvageable but not right so I'm going to try again. Ended up spending my time designing and cutting the new parts.
Latest blog entry: Sagitta 600 build 2018


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