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Gee Bee Dreamer Bipe

rockyboy

Skill Collector
Mentor
Last night I did the fiberglass layup for a cowl - and it didn't cure right :( All squishy and sticky - I must have got the ratio wrong.

But it came out of the mold without causing damage, and let me do a test fitting. And hey - look at that way off center prop! Can't have that - the right thrust on the center mounted motor just doesn't look right.

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So after moving the motor 7mm to the left, now the prop comes out in the center line! :D

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Then I opened up a new set of epoxy bottles and did another cowling layup. Tomorrow we'll see if this one is usable. :cool:
 
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rockyboy

Skill Collector
Mentor
I was so excited about getting the cowl on, I went to the shop before work this morning to peel it out of the mold. First step was slice around the rim to make a clean edge and tear off the ragged stuff.
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Then with a little twisting and tugging it popped right out!

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It's still pretty flexible, but pops back into shape. I hope paint will hold OK on it once it's mounted and not getting squished around...

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But with the prop hole in the center line, it fits and looks great! I'm thinking about putting some sort of louvers or vents above the prop using @willsonman 's aluminum flashing method...

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That's all for this morning though - need to clean it up, drill mounting holes, and put on a coat of paint tonight to make sure it's a usable part!
 
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rockyboy

Skill Collector
Mentor
Very cool, nice work on the cowl.
Thanks!

Cowling work continued into the wee hours of the morning. A couple coats of fill spackling and primer sanded almost entirely off to smooth it out for one final primer coat, and then fabricated a little aluminum venting louver for the nose out of some scrap. Also put a small exit hole in the bottom of of the cowl.

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I might need a little more exit venting, but I don't expect this motor to run too hot. The motor/prop combo should put out 5 pounds of thrust, and before the cowling went on, with battery installed, she only weighed 3.6 pounds! So the motor won't be working too hard (or heating up too much) and I might want to prop down a bit for the maiden flights.
 
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rockyboy

Skill Collector
Mentor
All done!! :D :D :D

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The white cowl is growing on me - especially with a handfull of screws adding a little flair.
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I screwed in the front louver too so I can remove it in case I decide to try and get a paint match the green.

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Look at that easy battery access! :D
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And one other functional touch I added - I got a cheap connector kit from eBay with dozens of different sizes that all work with standard servo pins. So I used a 6 pin housing for the ailerons - as long as I put the exposed metal part of the pins on the same side when I plug it in, the right and left ailerons will never get plugged in backwards! :D

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So she's all balanced, programmed, and ready for a maiden flight! I'll be heading to the field on Saturday for a Glider Day event - and I really want to bring this along too for a maiden flight either before or after the event. I don't want to tick anyone off bringing a biplane to a glider event - so it'll stay grounded during the event.
 
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TooJung2Die

Well-known member
There's one little detail that seems to be missing. There's no pinstripe on edge of the white nose cowl. All the other white borders have a pinstripe. It's not important, she's beautiful.
 

rockyboy

Skill Collector
Mentor
There's one little detail that seems to be missing. There's no pinstripe on edge of the white nose cowl. All the other white borders have a pinstripe. It's not important, she's beautiful.
That's exactly what's missing! Thank you! Not sure I can make it fit nicely with the line of screw heads, but I'll certainly be looking at that.

The maiden flight today went very well! She came home in one piece - no damage other than one bit of peeling pinstripe. :D

@wilmracer shot the flight video so that should be excellent - I'll do a full write up of the flight once that's ready to publish.
 

PsyBorg

Wake up! Time to fly!
Mentor
What a sweetheart that one is. Glides for days no wonky behavior.

Great build Jon. Just be sure that fancy front load always locks. Hate to see the motor and battery take off without the pretty parts.

Be like the pylon race at Swampfest all over again. 😁

Such a gorgeous build.

Maybe small exhaust ports with a few light oil smudges on that purty white cowl to contrast with the shiny of it all.
 

rockyboy

Skill Collector
Mentor
Thanks everyone! Yeah some exhaust ports would be neat - I'll put that on the list for sure!

Also a huge thank you to Carl @wilmracer for the video and nerve calming!

So the maiden flight had a couple challenges. Carl was gracious and edited out the 4 or 5 nose over's when trying to taxi out. Definitely need to move the wheels forward so they aren't so close to the CG.

Once I found a really flat 10 feet of field she practically leapt into the sky! I kept her at a shallow upline on takeoff to avoid any potential stalls till I was sure I had plenty of airspeed and a bit of clear air underneath her. It was a little nerve rattling at first cause I was pulling about half up elevator and more left aileron than I liked to keep her under straight. Once I ran the trims out to the ends she flew very much where I pointed her, but I wasn't up for a hands off pass at all. Maybe next time :p When I cut the throttle all the way she didn't dip a wing or nose dive - just stayed pointed straight ahead and started sinking. And when I throttled up she stayed level so the thrust angle is in good shape.

I was very concerned about nosing over on the landing, so when I cut power to glide in and I saw it was going to be short of the field, I decided to take advantage of the tall grass and just set her down there nice and level. The only damage from the maiden was a single piece of the black pinstripe that came loose. :D

There are a couple things to address before the next flight - most importantly moving the wheels forward and using subtrim to zero out the control surfaces. But I also want to put the black stripes around the cowl and add in some exhaust pipes :D
 
Uhh, hate to say this, but your landing gear leg bracket is on backwards. In full scale aircraft, the gear sits just forward of the CG such that in 3point mode 10% of the weight is sitting on tailwheel(or at least on Piper Pacers). in tail up flight modes on jack stands, there is minimal weight on tailwheel or just enough to keep it on the stand. In other words, if a breeze comes along your tailwheel falls off the stand. Ask me how I know that.

Also, in full stall 3 point landings, it can't nose over unless you stomp the brakes REALLY hard. Once again, ask.........
 
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rockyboy

Skill Collector
Mentor
Uhh, hate to say this, but your landing gear leg bracket is on backwards. In full scale aircraft, the gear sits just forward of the CG such that in 3point mode 10% of the weight is sitting on tailwheel(or at least on Piper Pacers). in tail up flight modes on jack stands, there is minimal weight on tailwheel or just enough to keep it on the stand. In other words, if a breeze comes along your tailwheel falls off the stand. Ask me how I know that.

Also, in full stall 3 point landings, it can't nose over unless you stomp the brakes REALLY hard. Once again, ask.........
The weird thing is the build instructions specifically called for the bracket to be installed this way which puts the landing gear barely 3/4" of an inch in front of the CG. The way the plane sits now, it probably is pretty close to 10% of weight on the tail, which is appropriate for full scale but not going to work for model sized rough field flight. If the bumps in the grass runway I fly on were scaled up it would be like taking off a runway cratered with 18" deep holes!

If swapping it around and perhaps putting a little washer under the back to get the wheels about 1.5" in front of CG doesn't make it handle better on the ground, I'll be building some custom soldered together landing gear arrangement.

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Perhaps it would be workable for a paved field like it is, but neither of the fields I fly at are that smooth. :D
 
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