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Aug 04, 2006, 07:59 AM
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Electra Build


With this posting, Im about caught up to present build status. There is something about watching a wing take shape that gives a real feeling of accomplishment. Sheer size and structural beauty I guess. The wing went together well, but I was disappointed that many of the rib slots for the main spar were cut too tall. I put a drop of epoxy in the gap for the worst ones and let Titebond fill in where it could on the others.
Last edited by k4kjf; Aug 21, 2006 at 05:47 AM. Reason: grammer
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Aug 06, 2006, 08:30 PM
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Rib Shims


Not sure if it makes much difference structurally, but on some of the center ribs before gluing them in place with Titebond, I CAed some 1/16 stock as shims into the generously cut slots for the main spar Wont be visible once the center sheeting is on, but I feel better about it.
Aug 07, 2006, 11:43 AM
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Leading Edge Sheeting


Im trying to minimize the use of CA. However the rubber band affair shown here did not maintain sufficient downward pressure to assure good contact between the top of the rib and the sheeting over the length of the joint. So instead, I applied Titebond to the rear half of the portion of the rib that would be under the sheeting. Then used the rubber bands as shown to hold the sheet in place. Finally used thin CA letting it wick into the joint between the LE and the sheeting and hopefully to the joint between the top of the ribs and the sheeting near the front also. I worked along the joint from right to left, doing an inch or so at a time. (Apply a drop, hold it for 30 sec, move one inch to the left, apply another drop, )

All this was preceded by a careful sanding session on the leading edge sheeting itself to get it to mate as perfectly as possible with the surfaces that it butts against on the three sides. Went very slowly so as not to overshoot.
Aug 12, 2006, 03:19 PM
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Tail Surfaces Test Fit and Final Wing Sheeting


No glue on the tail surfaces yet, but after some sanding on the bottom of the fin, a trial fit of it and the stabilizer looks good. Also temporarily secured the wing in place with rubber bands and checked for parallelism between it and the stab.

Glued in the last bit of wing sheeting this morning. Using about half Titebond and half CA. Titebond on the tops of he ribs and CA for the sheeting butt joints. Put quite a bit of sanding effort into this to eliminate or minimize gaps.
Aug 13, 2006, 07:58 PM
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Wing Center Tape and Cowling


CG Super Jet (CA) was recommended as the adhesive to use to bind the nylon cloth strip around the wing at the center joint along with a prominent warning about having adequate ventilation available, protecting fingers etc. I decided to use Titebond instead.

Starting on the bottom of the wing, I first put a bead of Titebond down along the center joint and then laid the nylon strip over it, pressing it down and working it smooth with my finger. The Titebond was a little on the thick side and in doing this I tended to push the tape out of alignment which had started out nicely centered over the joint. Wetting my finger with water while doing this made it much easier. The slight dilution of Titebond allowed it to flow and smooth out nicely and the nylon strip stayed centered over the joint as it was suppose to. The tape disappears pretty well into the wood after the glue dries.

While the tape was drying, I started looking at the cowling, how it fit, and how it was to be attached. Im going to have to do a little sanding on the arch over the motor above former A to allow the cowling to overlap the front of the fuse by a good 3/8 as the plan shows. And, Id like to find a better way to attach the cowling to the fuse than just the small wood screws into soft balsa.
Aug 16, 2006, 09:44 PM
Lee / RC Enthusiast
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Just checking in on your progress. I got modivated after reading your thread and finally took my Electra apart to "fix 'er up" a bit. The brushless motor I had on it (the first one I ever bought) was never the right choice for this model. I've yanked out her electronics and plan to give her a new face-lift.

I dusted off my Electra ARF the other day and gave her a toss. I changed out the NiMH battery with a LiPo and that has really saved some weight. She actually balances quite nicely too.

Hope it's going well.

-Lee / YarSmytheJr
Aug 17, 2006, 06:32 PM
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Two forward, one back.....


Didn't like attaching the cowling with small wood screws, so decided to follow Old_dude's example and instead use machine screws and nuts epoxied to the inside of the fuse. Only problem was that the half-tube motor cradle was already epoxied in place preventing access to the area I needed to get to.... So I ripped it out. Came out easier and cleaner than I expected though, so I'm happy about that. Now to get that cowling mounted.

Hey Lee - Glad to hear you have been inspired! How about posting some "before" photos, so we can appreciate your efforts when the "after's" become available?

Ken
Aug 20, 2006, 06:57 AM
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Cowling


I like this better. Used 4-40 blind nuts anchored with a little epoxy.
Aug 20, 2006, 12:54 PM
If u wind it it will run!
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looks like a nice job the electra really does fly great. my first plane was a gentle lady which is pretty much the same as a electra, and it was great to learn on. i hope you enjoy your plane
Aug 20, 2006, 07:46 PM
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Thanks usedhippo - I have a Gentle Lady waiting here as the next project. Actually I had purchased it first, but decided that because Im not flying with a club yet and therefore not having access to a winch, the Electra might be a better first sailplane. - Ken
Aug 23, 2006, 06:50 PM
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Spinner/Cowling Alignment


Not a big deal, but Ill know how to do it better next time. What I did this time was to draw reference marks on the fuse to align the back edge of the cowling with the front surface of former A. The result was that later after the spinner and prop were installed there was noticeably more gap between the spinner and the cowling at the top than at the bottom. Not real noticeable, but slightly irritating. To improve alignment I elongated the holes at the bottom of the cowling to allow it to somewhat pivot into alignment with the spinner before snugging-up the mounting screws. Came out ok I guess you have to be looking for it to see any misalignment.

But, next time a better approach would be to drill the mounting holes in the cowling, temporarily mount the motor, slide the cowling in place and mount the spinner on the motor shaft. Then mark and drill the cowling mounting screws in the fuse. Or do like old_dude did and use slots in the cowling that continue all the way to the back edge instead of just round mounting holes, Besides making cowling installation easier, they would probably provide enough adjustment to take care of any misalignment as described here.
Aug 23, 2006, 08:30 PM
Lee / RC Enthusiast
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The photo shows a one-piece prop. Are you going to consider using a folding-prop?

-Lee
Aug 24, 2006, 07:21 AM
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Folding Prop


I'm planning on a folding prop Lee, but have not yet looked for/found a suitable one yet. Back when I was planning on jumping right in with a gearbox and a larger prop, it was apparent that many recommended the Master Airscrew folding 12 x 8 and I was going to get that....

But now that I've decided to at least initially go with direct drive, I've not located a suitable folding replacement. I assume that I need to stay with something like an 8 x 4 in size.

Any recommendations?

Ken
Aug 24, 2006, 08:03 AM
Lee / RC Enthusiast
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Quote:
Originally Posted by k4kjf
I'm planning on a folding prop Lee, ...Any recommendations? Ken
Hobby Lobby - Graupner CAM folding props

This is the type I use on both of my Electras. I think mine are 9x6" but you can buy the adapter and extra blades to experiment.

I also have a Graupner Scimitar folding prop. It's a bit cheaper. But if I recall, they didn't fold completely on the sides of the Electra.

-Lee
Aug 28, 2006, 11:11 AM
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Progress


This feels like a milestone of sorts. I still have to go back and epoxy the plastic half-tube motor cradle to fuselage supports. But once that is done, Im ready to sand and cover. It's starting to look like an airplane!


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