Espritmodel.com Telemetry Radio
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Old Nov 19, 2012, 09:20 AM
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Rafe,

Great build and great build thread. Thanks for taking the time to illustrate so well, your pictures are outstanding and the comments/instructions are top notch. I think I learn more about building a particular plane from build threads like this than a set of instructions. Very nice work.

I liked the book idea although I never pegged you as a "Deadhead".

Wave that flag...

Dan
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Old Nov 19, 2012, 05:50 PM
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Hey now, Dan, I wondered if anyone was paying attention. Good catch on the books. Ever tried flying to Dark Star? Under the right conditions, it's...

Build is now down to the covering, and maybe if I get ambitious in Illustrator, some decals from Callie.

Fuse covering will be interesting. What I'm thinking: cover top and bottom separately, from nose back to R/E servos or thereabouts. Then... glue top and bottom together, and cover what's left, ie. the aft-most part. Once top & bottom are joined, it makes for an unwieldy part that needs delicate handling and storage.

Also need to be sure not to cover the two surfaces that will join with the black fiberglass tube.
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Last edited by rafe_b; Nov 19, 2012 at 09:35 PM. Reason: typo
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Old Nov 20, 2012, 04:51 PM
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Fuselage covered...

Pretty much according to plan. There is minimal covering on the surfaces where the two fuselage halves face each other, or where the horizontal stab will attach.

I left one "bay" on the fuselage completely open for the rudder and elevator servos. The ribs on either side of that bay are hardwood.

Might get the tailfeathers covered before the weekend... or not, depending on how the festivities go.
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Old Nov 21, 2012, 06:40 PM
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The end is in sight. Covering these flat bits is really a no-brainer.

Just the main wing and h-stab left to cover, then it's at "ARF" stage... at which point I'll be dealing with servos and linkages, motor mount, landing gear, final assembly, and decoration.

Plans suggest you route the R/E servo wiring up through the tube, but I don't think I'm gonna do that. I want it accessible.

In any case, I'll do another mockup assembly, for a re-check of CG and final weight. I can imagine it might need more weight up front to counter all that covering on the tail.
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Old Nov 24, 2012, 09:19 AM
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I wish I'd done this mock-up a bit sooner. I'd have moved the motor another 1/4" or 1/2" forward. I may need to re-locate it.

The 2nd photo shows how the battery will mount... more or less. There's a lot of stuff riding on this motor mount block. Stock landing gear setup seems very clever, but it precludes mounting the battery any other way.

The hardwood firewall is attached to the main motor mount block with a couple of short sections of 3/16" threaded rod.
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Old Nov 24, 2012, 10:06 AM
wood is good
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That battery mounting just looks wrong.
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Old Nov 24, 2012, 07:46 PM
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Originally Posted by loNslo View Post
That battery mounting just looks wrong.
I don't see another way to mount it if I'm gonna use the stock landing gear legs. And so far, I'm liking the way the stock LG is rigged. If it were nitro powered, there'd be a gas tank hanging off the side. I'm not aware of any other Mojo or Primo 40 "electrocutions" to use as references or examples.
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Old Nov 24, 2012, 09:19 PM
wood is good
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Your post #25 showed a practical and sound arrangement.
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Old Nov 24, 2012, 10:41 PM
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Your post #25 showed a practical and sound arrangement.
That photo doesn't show the LG in place. The LG complicates things. In order to mount the battery as shown in that picture, it'd have to be have to be raised off the surface of the fuselage to clear the LG. Do-able but not as simple as it seems. It's a thought, though.

Battery doesn't look so weird when the rest of the fuselage is shown. Has the advantage of having its mass as far forward as possible, and anchored to a very solid firewall surface.

In any case, it's kind of amusing to be discussing the looks of a profile plane. I mean, they look strange from the get-go. We'll see how CG works out with both arrangements.
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Old Nov 24, 2012, 11:20 PM
wood is good
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Looks, meaning not just aesthetically. You're making a canard of it.

Had you considered the space behind the LG, within the profile fuse? You'd just be eliminating a few ribs and framing the opening.
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Old Nov 25, 2012, 09:02 AM
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Photos offered without comment -- how batteries are attached on a couple of my smaller profile planes.

Update #1: It occurs to me, this might be a good place to parallel up a pair of smaller batteries, one on each side of the fuselage. It'd look a bit more symmetrical in any case.

Update #2: Latest mock-up shows that I'm gonna need at least another 6 oz. or so of weight on the nose. So flying weight will be pushing 4 lbs. A bit disappointing but not altogether surprising.
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Old Nov 25, 2012, 05:57 PM
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One more trial-run at a fully-assembled plane. With 17 oz. (!!) of batteries, I can get CG back in range... just barely.

All up weight is now around 60 oz. The main wing still needs covering, and there's still a few servo linkages to add.

I'm dragging my feet on covering the main wing 'cuz I'm still deciding how to proceed -- a simple stitched-together pattern of two or three colors, or solid yellow (same as the rest of the plane) with stick-on decorations.
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Old Nov 26, 2012, 08:52 PM
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Alrighty. Worked up some decals for Callie, something like the image below. Some text for the bottom sides of the wings... something I've always wanted to do.

I've modified the motor mount (again) so that the motor is about 3/4" forward of its previous location. I'm seriously thinking about a 2-pack battery arrangement, say a pair of 4S/2000 or thereabouts. One pack on each side of the fuselage, nice and neat.
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Old Nov 27, 2012, 12:50 AM
wood is good
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Really good looking graphics.

My Cub is being built for (2) 4S 2200's:
http://www.rcgroups.com/forums/showthread.php?t=1742597
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