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Jun 28, 2020, 02:04 AM
B for Bruce
BMatthews's Avatar
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First FF forum Theme Build- All balsa glider


OK, let's get this started and see how it rolls. The first FF forum theme build that I've seen since joining RCG.

The theme this time around is some manner of simple all balsa glider.

The idea is to build one or more simple all balsa gliders that can be completed in an evening or two. So nothing fancy and major. If you take more than two evenings it had better be a good excuse or you've picked something out of the scope of being a "simple" build.

Designs can be conventional or oddball, for fun or contest use. Existing plans or design your own. And you're invited to build more than one design.

Since this is supposed to be a low key thing the Official start time is the post time of this thread and let's run the project this time around for two months. That way those that were not sure can dive in with time to spare.

Post all you plans and progress in this thread so we can all enjoy. If you design your own please share the plans if you don't mind.
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Jun 28, 2020, 12:23 PM
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Sorteador


Ill start....

El Sorteador from Zaic Model Glider Design book... Not much on the net about it other than designed in 1942
Jun 28, 2020, 12:28 PM
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kevin matthews's Avatar
I have gotten started. I chose a design by the late Andy Lennon. In his book "The Basics Of RC Model Airplane Design" he offers a plan he called the "Plover". A. Lennon states it was meant to be a canard but turned out to be a glider ( from what I can gather from reading ). He did not say much about this design as compared to some of his other self designed RC models. I sized the plan for a 24" wing-span. The sheet wood I am using is fairly light balsa 1/16" thick. I've made the fuselage thinner than the plan calls for with the thought I can add ballast as needed later on during the balancing phase of my model. The CG is given on the plan. The Plover is a swept forward wing design with a rudder. I used the large plan I printed out to cut the wings out by measuring, and marking right on the wood, and cutting with a #11 blade Exacto knife. Yesterday I soaked the 4 wing sections in warm water for about 10 minutes in the sink. I made a single stick form to bend the wing sections over which tapers from 1/8" to 1/16" for the inner wing sections. For the outer wing sections the stick form was 1/16" to flat. I secured the wing sections over the stick forms so the peak of the airfoil was at 25% of the wing chord, pinned them down at the LE, and TE, and left them to dry over night. This morning they were dry, and held their airfoil shape. The sections fit together closely but had to add a little weight for one of them to hold the joint down so it matches. I used the Gorilla wood glue. I have about 2.5 hours into the build if the over night drying does not count. Feel free to use this design for yours.

Kevin
Jun 28, 2020, 12:30 PM
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kevin matthews's Avatar
Waiting for the wings to dry.

Kevin
Jun 28, 2020, 01:57 PM
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kevin matthews's Avatar
I sanded the TE & TE to a more aerodynamic form. There is a strip of white Esaki tissue at the wing joints on top. In this picture the wing is put together over an airfoil form which will be permanent, and glued to the stick fuselage. The plan calls for 5 degrees dihedral, but that is for an airplane with working ailerons. I've added more. The wing tips are formed as per plan. I used a sanding block to sand the wing roots so they would fit together with the dihedral, and airfoil. I determined at what height the jigs would need to be for the dihedral I wanted so I could butt up the wing root to the sanding block, and take some of the wood off in the middle space of the wing at it's roots so the 2 semi-spans would butt up together. Once I got it all together I decided it needed more dihedral, and added to the jigs under the wing. It didn't affect the joint spacing very much.

Kevin
Jun 28, 2020, 02:17 PM
B for Bruce
BMatthews's Avatar
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Looks strongly pterodactyl looking...
Jun 28, 2020, 02:20 PM
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kevin matthews's Avatar
Ha Ha, Cool, Huh?

Kevin
Jun 28, 2020, 04:42 PM
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kevin matthews's Avatar
The wing on the fuselage. I placed a strip of Esaki at the center wing root joint. I'm holding the stick fuselage with balsa jigs to keep it vertical, and to hold it still. There is an airfoil under the center joint that I had to sand down so the wing's LE & TE would lay flat on the fuselage. The wing incidence is 0 degrees.

Kevin
Jun 28, 2020, 06:03 PM
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Gluehand's Avatar
That's cool Kevin.....like a reverse Spook....!
The reflex spoilers, positioned at the tips in the case of Spook, have moved to the wing root of Plover (what's named "Spoil-Flaps" on your plan), providing the neccesary incidence..... Make these adjustable.

I'll follow this project...
Jun 28, 2020, 06:13 PM
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kevin matthews's Avatar
Thanks for the tip, GH.

Kevin
Last edited by kevin matthews; Jun 28, 2020 at 06:19 PM.
Jun 28, 2020, 06:18 PM
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kevin matthews's Avatar
The rudder. It's supposed to have a dorsal fin which broke off, so I'll add that later on after the glue dries. The size of the rudder was somewhat of a guess.

Kevin
Jun 28, 2020, 07:14 PM
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You are moving along quickly Kevin!!!.... Interesting design!! ...Will look really cool in the air... How do you plan to launch it?
Jun 28, 2020, 07:19 PM
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kevin matthews's Avatar
i added rear fairings to the wing but, had to extend the rudder to reach to the tail end. I'll cut away some of the rudder in front to compensate. A little sanding is in order, as well. 777, I plan on hand tossing to begin trimming, and then trim for catapult launching.

Kevin
Jun 28, 2020, 07:28 PM
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Drawing and templates finished....Original was 20 .... This one will be 14 .... A little smaller to hopefully to stay in the park better...

I plan to gentle cat launch it .... Will have to see if that sub fin has to be made smaller..... Next opportunity to work on it is next weekend.....
Jun 28, 2020, 08:50 PM
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kevin matthews's Avatar
I cannot get the Plover to glide, or even resemble a short glide. I may try again with flat wings because I suspect it's the under cambered airfoil causing it's failure. Chock this one up as a learning experience.

Kevin


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