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Old Jan 20, 2013, 04:55 PM
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Utah, USA
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Attaching the nose planking and fuselage sheeting

Here is the planking process as given to me by my Australian friends in an early version of the fuselage construction manual:
1. Plank the top of the nose from the main side stringers and over the top from F1 to f12 (3mm or 1/8" balsa).
2. Glue in the F12a balsa doublers (to attach the rear sheeting).
3. Sheet the top surfaces down to the same point from F12a back to the tail (3/32" sheet is recommended, light to medium weight).
4. The model now has sufficient strength to be removed from the supports.
5. Once the supports have been cut off and former bottoms sanded smooth, flip the model into a foam or padded cradle.
6. Plank the front bottom of the model from F1 to F9.
7. Glue in the balsa doubler F9b.
8. Sheet the bottom of the model from F9b back.

So let's do it! Below are photos with captions of the above process, with some slight modifications. I will be using Titebond III still, and am in no big rush, so only a few pieces at a time will be glued, clamped, and left to dry, with wetting/bending/drying then gluing, as needed. In the back, where larger sheets can be used, there will be some wetting and pre-bending to make the gluing and clamping easier.

The first nose plank took some force and ingenuity to get it tight against F1, so I am soaking the front third in HOT water and clamping in place to pre-bend the end before gluing. Softer balsa would be less of an issue, but there are downsides: will crush, break and show clamp marks easier, and you must be MUCH more careful when sanding.
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Old Jan 20, 2013, 05:00 PM
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Utah, USA
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Planking around the upper canopy frame was problematic. The laser cut parts and prototype build log show the sheeting curving up into the upper canopy frame. Other full-size photos show the sheeting following the nose curve into the canopy frame, which is what I decided to do (will require some fill to get it right). Every full-size canopy I have photos of is slightly different.
As the photos show, my chosen sailplane (CGU) has a totally different canopy attachment—I may make both canopies, or just be non-scale on this detail.
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Old Jan 22, 2013, 11:47 AM
Designing something...
United States, CA, Cameron Park
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Quote:
Originally Posted by shinck View Post
After sending the files out, we (me and the laser cutter) found out that they needed some cleanup work as the smooth curved lines were actually made up of very short segments, which really cause problems on the laser cutter.
I just noticed this from post #6.

This no doubt has to do with polylines vs. splines. What CAD program are you using? Rhino has the options on how the file is exported. Then again It may have happened to the file you got from rcplans.

Brian
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Old Jan 22, 2013, 11:55 AM
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United States, CA, Palmdale
Joined Nov 2007
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Quote:
Originally Posted by cpdude View Post
I just noticed this from post #6.

This no doubt has to do with polylines vs. splines. What CAD program are you using? Rhino has the options on how the file is exported. Then again It may have happened to the file you got from rcplans.

Brian
Brian,

Yes it was an issue with the way it was exported. We tried to iron it out before it got exported, in the end I just ended up taking care of it. Much of it was polylines, but a good deal was simply overlapping lines that needed help. It's all fixed up and ready to go now.

Red
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Old Jan 22, 2013, 12:29 PM
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Thanks, Red, for the technical explanation.
I am admittedly not a CAD guy, though I am OK on Adobe Illustrator. I was just kind of the messenger and recipient on the original cutting files.

Scott
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Old Jan 22, 2013, 02:51 PM
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ENGLAND
Joined Jul 2001
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re Oly 2b canopy bubbles.
The original Elliot canopies were simple heat laid bubbles and varied in shape and optical quality (or lack of it) significantly. As they invariably got broken in club use they were replaced often with Slingsby Swallow bubbles which were readily available, both the early type which was similar to the original Elliots bubble and the later wider and better version as per your last image. K6cr bubbles were also roped into service if you could get your hands on one. The wing fillets were also frequently made out of perspex as the vision was pretty poor without.

Plenty of other canopy bubbles were made to fit, if obtained cheap enough, often salvaged from wrecks.
On my NORD 2000 (French built Oly Meise) I replaced the original yellowed bubble with a L Spatz canopy from a wreck and made the wing fillets from flat sheet bent over a ply former using an electric fire "borrowed" from my grandparents......

Gordon
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Old Jan 22, 2013, 04:11 PM
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Thanks for the history. No wonder, after 50-60 years, there are so many different types.

Scott
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Old Jan 27, 2013, 07:23 PM
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Both sides were formed before gluing in place.
Mark all formers on the inside of the sheeting to show where glue needs to be.

I will be using a coat of glue (Titebond) on both the sheeting and the fuselage formers/longeron/spine, letting it dry, then attaching the sheeting to the fuselage using a hot iron. Kind of like contact cement, but movable until heating and setting the glue.

Sorry, no photos of this ( will show the bottom sheeting), so I will write a thousand words to describe it (just kidding!).
Used two clamps to position the bottom edge of the sheeting at the center of the side longeron.
The old household iron was set at Cotton, and I started the process from the bottom/longeron and slowly worked up on each former as I went back and forth on the fuselage.
I heat set almost to the top spine, trimmed the sheeting in the middle of the spine, then set the glue at the very top. Other side was done the same.
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Old Jan 29, 2013, 11:37 AM
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There were two difficult areas to envision on this build: 1) the canopy/wing transition that we will get to later, and 2) the wing pylon sides and TE transition area on the top of the rear fuselage.

I looked at a lot of full-size photos, the Charlesworth plans, and 2 other build logs. Charlesworth appears to have the only model/plans that got the pylon and TE transition right, but those are not the parts I have. So, not being a competition scale model, I just went with the flow. Maybe on the next one…
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Last edited by shinck; Jan 29, 2013 at 11:45 AM.
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Old Jan 30, 2013, 03:07 PM
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Utah, USA
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Stab mounted servo

A little break from the fuselage build while I think about the tail surfaces.
The original prototype called for an HS125MG thin wing servo in the stab to run both elevators. Torque = 42 oz/in, weight = .84 oz
I was thinking an HS 85MG. Torque - 42 oz/in, weight = .77 oz
Of course I will have to make sure it is thin enough to fit.
But then I saw the Flair KA8 build where two HS85's were used, one for each elevator.

What do you think?

Scott
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Last edited by shinck; Jan 30, 2013 at 03:13 PM. Reason: added info
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Old Jan 30, 2013, 07:49 PM
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Scott,

My Flair Ka8b has only one HS225BB servo (54oz-in) in the stab, to operate both elevators (via joiner wire). I have never once had any compunction about this set-up, and it has performed without any problems whatsoever. I would imagine a single HS85MG would also do the job just fine, for a sailplane the size of your Olympia (assuming you keep the airspeed below redline!).
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