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Gee Bee Dreamer Bipe

rockyboy

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#1
Time for another swap meet rescue build! :D

This time it's the classic Dreamer Biplane designed by Jon Foster with plans published in the June 1972 Flying Models Magazine. The specs are 39.5" wingspan, designed for .40 sized glow fuel motor, and 4.5 pounds. The design was later kitted by Gee Bee, and one of those kits was partially built, tossed back in it's box with a ton of little broken balsa bits, stored in an attic for a couple decades, and then sold at an RC auction in 2018 to a sucker... er... enthusiast, which brings us here :D

A couple beauty shots of what it's supposed to look like...




When I started researching this kit and discovered it was based on published plans, I had to go looking for the magazine where it was published. Thanks to eBay, I found it :D

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The plans in the article are a little different that what's in the kit - reformatted from one page to two pages, added interplane struts, switched the horizontal slab to a truss style build. As I go along I'm sure I'll find other mods too.

And speaking of the kit, here's what I bought at the auction.

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Time to sort out this pile of wood and see what state things are in. Horizontal stabilizer looks good - vertical stabilizer was broken in half along the grain, but easy to glue back together. A little splintering in the wing sheeting to glue back down. Plans are in good shape - a little foldy, but stretched out under a piece of glass nicely.

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The bottom wing looks straight and true, with the right amount of dihedral. For some reason the cap strips on the ribs had all been installed, and then ripped off one at a time and tossed back into the box. o_O

Oh well - starting on the bottom of the wing I cut and installed new cap strips. Next I made hatches and installed cross bracing for a dual aileron servo install. Just holes in the hatches now, will turn those into slots with a scroll saw tonight.

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Next will be finishing up the aileron servo mounts, cutting the ailerons, holes for hinges, cap ribs at the wing tips, and then the curved wing tips.

Debating if I should stay with the classic rubber band mounting - which is much friendlier to a bumpy landing - or building out some bolt on mounts....
 
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rockyboy

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#3
So I think instead of choosing between rubber bands and bolts I'm going to choose "both". :D

I'll install and thread the mounts for a nylon bolted setup, but also leave the cabanes long and install the fuselage dowels for rubber bands. To start with I'll fly her with rubber bands and leave the covering over the bolt holes in the wings.

I've noticed in the original design, there weren't any interplane struts and the wings were only supported by the rubber bands at the fuselage. In the kit plans, there are plywood interplane struts called for, and they fit into "slots" made into the wing ribs. This strikes me as a bad idea as any sideways kind of crash motion is pretty guaranteed to tear out a wing rib or two. So for the interplane struts, I think I'll make them with tiny 2-5/6 nylon mounting screws instead that will shear easily if I tumble a landing on rubber bands or bolt in mounting. The trick here will be making a solid enough but lightweight mounting block for them to mount in the wing so the tiny nylon screw will snap instead of tearing out the mounting block.

I'll also plan on using nylon mounting bolts for the landing gear bracket too.

So why am I planning so much for break-away parts? I'm building this for our club's biplane fun-fly contest that every summer includes taxi races. These are really funny to watch - but they can be pretty hard on planes too :LOL:
 
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rockyboy

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#4
Aileron servos mounted and adjusted tonight.
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To finish up the lower wing the punch list is...
  • cutting the ailerons
  • cutting holes for hinges
  • making cap ribs at the wing tips that go back the full length of the aileron
  • installing curved wing tip pieces and spars
  • installing mounting blocks for the interplane struts on top side
  • install bracing for mounting bolts at center
  • installing rib cap strips on the top side of the wing
  • sanding everything smooth
  • check if fiberglass reinforcement is necessary at the center
And then it's on to the top wing! :D
 
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rockyboy

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#5
Ailerons cut and hinged. Implements of hinging laid out here too. I like the Robart hinges cause they install with a round hole, which I tend to do a little better than the horizontal slots most days.

The little awl with a loop handle is nice to start the hole in the balsa so the drill bit doesn't try to wander around. After the hole get drilled, it's time to widen out the top part of the hole with the reamer (that's the T handle thing with really sharp flutes running down the long part). I got it for doing guitar and stringed instrument work but it's been really useful as a prop reamer and for hinging too. :D The final step is to use the knife to square off the top of the hole.

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So after lots more plans study I'm going with this approach for the wing tips
- the big curvy piece gets glued on, then I'll do a little flat part glued on the end to make a clean separation for the aileron, and then the ribs go in. Should work out fine, and without unnecessary weight.
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So here's the updated bottom wing checklist.
  • cutting the ailerons
  • cutting holes for hinges
  • making cap ribs at the wing tips that go back the full length of the aileron
  • installing curved wing tip pieces and spars
  • installing mounting blocks for the interplane struts on top side
  • install bracing for mounting bolts at center
  • installing rib cap strips on the top side of the wing
  • sanding everything smooth
  • check if fiberglass reinforcement is necessary at the center
 
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rockyboy

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#7
Are you powering it by gas or electric?
She will be electric - no wet fuel in the house is one of the agreements that keeps me both in the hobby and married. :p

Made a little bit more progress last night too. Here's the little flashing piece getting glued to the wingtip and creating a nice surface for covering next to the aileron.

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And time to add ribs onto the wingtip.

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I thought this insert on 1972 model kit innovations was cute. They are right about this

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rockyboy

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#8
Sanded the wingtip pieces all into shape.

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And gluing on some extra bracing where the interplane struts will go.

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Might as well get the hinge slots for the rudder going...

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And now that I have a clean spot on my metal building board it's time to start laying out the top wing. :D

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Sort of nice the ribs were already cut by the previous builder. Makes this part go faster :D

Here's the updated bottom wing checklist.
  • install bracing for mounting bolts at center
  • installing rib cap strips on the top side of the wing
  • sanding everything smooth
  • check if fiberglass reinforcement is necessary at the center
 

rockyboy

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#9
Rudder hinges finished! I've got one of the slot cutting tools that uses an xacto knife handle, but I've found that I have better control of the tool if I just hold it in my fingers rather than use a handle. The down side to that is my finger cramp up after just a couple slots, so it's a multi-day process to get all six slots for a panel done. And I have 12 more slots to do for the split elevators... maybe I need to experiment with making a little nubby handle for the slot cutter... :unsure:

Also finished the rib cap strips on the top side of the wing. At this point I need the fuselage to be framed up before figuring out the bolt bracing, so I get to set this wing to the side as "done for now" :D

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Next up, framing the top wing and cutting elevator hinge slots... :D
 

rockyboy

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#10
Top wing framing!

Spars on the ribs...

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Center plywood joiners going in...
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Sheeting over the trailing edge...
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Turned the board around so it was easier to line up the leading edge...
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There's a lot more curve on the leading edge sheeting, so I sprayed it with ammonia to make it flexible and clothes pinned it in place to dry...
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And installed the elevator hinges while that's drying...
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rockyboy

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#12
Flipped over and looking good!

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Time for the little triangle braces at the wing joiners on the bottom of the wing...
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And after a touch of sanding it's time to start with the sheeting on the bottom.

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rockyboy

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#15
Gluing up the second to last piece of wing sheeting.... I'm standing it up so I can get it off the building board entirely in a moment.
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Now it's time to study the fuselage build plans for a while and see what I can figure out here.... I suppose turning the picture right side up would be a good start too.. I'll take some more close up pictures of the entire plan before I start building too. Once I put one of the big solid pieces on it'll block a whole bunch of writing on the plan, and I'm going to need to refer to those notes.
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rockyboy

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#16
And the last of the wing sheeting glued to the top wing! All that's left on the top are wing tips, mounting blocks for the cabane struts, and rib caps.
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Plans are right side up now :D Since this design was meant for glow fuel, it's built like a tank. Thinking of ways to lighten it up and make it work better with electrics....
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Going to try something I've seen John Morgan and @willsonman do - build a removable power tray for the motor / esc / battery. The idea is that all these pieces will just slide into the fuselage on rails, and be held in place with a pin. When the battery is empty, pull the pin and then the whole tray slides out, easy peasy. No need for figuring out where to put a hatch big enough for the battery - the whole nose just comes out! :D

Of course this is just a stand in motor - just made an educated guess on the final weight and power requirements and placed an order for the motor and esc from Heads Up Hobby tonight. Should have it by Wednesday. :D
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In the meantime, I can build the tray and some other pieces. So here's a 3" square firewall being epoxied to the 2.5" x 5.5" battery & esc tray with a couple angle braces. Once this dries, I'll add some additional triangle bracing to make sure it's a very very solid glue joint.
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