Scratch Designed/Built Sailplane Fuselage

[Nodd]

Thanks Karolenaz.

Canopy
Not feeling like reinventing the wheel I set about installing the canopy in my usual way. First I built a simple frame, used kitchen wrap to keep the glue from sticking to the fuselage...



Sheeting is glued to the frame...



Second layer of sheeting, the lamination should help maintain the curved shape...



Sanded flush...



A clearer view of the sub-frame...



A coat of gray paint & on goes the soda-bottle canopy...



She's looking kinda sexy...



Time once again to let the glue dry.

[mclarkson]

That looks really, really nice!

[Nodd]

Thank you. Yeah I like the gray, gives the impression of depth under the canopy without eating up valuable electronics space. Best of all, with the canopy on there, my fuselage no longer looks like an giant Elf's shoe.

I got a few odds & ends done today... Trimmed the excess plastic from the canopy. Scared myself silly drilling a hole up through the pod to the wing-saddle for the wing's servo wires, turned out okay. Performed a balance test to see how much weight I have to play with for the tail.

Y-Tail
After some thought I think I'm going to stick with a V-tail for this bird but I'll be adding a small sub-fin effectively making this a Y-tail, fun fun...



Once again I used the sailplane V-tail calculator from tailwindgliders.com to figure out the tail sizing & geometry. And before anyone starts worrying about the V-tail angle, that'll be set at the usual 110°.

I thought about adding a small rudder to the sub-fin but that'd take another servo & require an extra channel which my DX7s doesn't have. Would have been cool & an interesting mix with the V-tail's ruddervators but there's really no need for a rudder. I'll get to designing the tail's structure tomorrow.

[Nodd]

After some more CAD work I printed up a set of ribs for the tail...



I plan to use dowel for the tail's leading edge hence the curvy bits...



Rough cutting using the scroll-saw...



Pile-o-riblets...



Sanded to shape using the belt-sander...



Printed up a set of plans...



I'm using a thin strip of carbon-fiber to stiffen up the tail's main-spar...



Glued the carbon-fiber to the spars...



Time to start putting this together...



Everything was going great until I looked up at the clock. Doh' it's 1am, time to call it a day...



I expect I'll get these finished up tomorrow, I'm off to bed Zzzzzz...

[Nodd]

Picking right up were we left off yesterday, setting up the dowel leading edge...



More progress...



Here's some pieces that'll makeup the root area. Going to layer balsa - light ply - balsa...



Root area built up & reinforced...



When I did my balance test the other day it took 4 oz on the tail-boom to make her sit level. It looks like we're well within limits so far...



Added some fancy tips...



Seeing what she looks like...



This tail feels sooo much stronger than the original, loving those diagonal ribs.

[Turner]

You are an inspiration to this 60 year old wannabe builder. Great work.

[Nodd]

Sounds like it maybe time to go buy some balsa Turner *smile*

More overly engineered fun...
I've been thinking about how much abuse my sub-fin is likely to take during landing, especially if I catch a wing-tip & the tail hits sideways...



I've decided to build in a little insurance, a sub-fin that'll bend instead of brake...



As you can see its made from two pieces of ply. Holding them together will be some coat-hanger wire. It's soft enough to bend if she hits hard, hopefully absorbing the impact instead of just snapping off...



I layered carbon-fiber either side then drilled holes...



Some Kevlar thread & plenty of epoxy holds the wire in place...



Added light balsa on the sides to hide the uglies...



That takes care of that, next is the lower fin part...



More carbon-fiber, mostly to keep the wire in place but also for ding protection...



Sanded the other piece to a nice smooth shape...



More progress on the sub-fin...



Test fit. Note I added a slight bevel where the two pieces join. Like a rudder's hinge, this should allow the fin to bend if need be...



Well that was fun...

[Nodd]

Time for another balance test
All this stuff needs to fit in there...



Yes! It fits...



Slung the tail over the boom & stuck her up on the balance stand. It looks like we're a tad nose heavy...



I'm okay with nose heavy at this point. The tail still needs to be glued on there & covered, push-rods & other hardware added, that'll all add weight to the tail.

110°
Happy with the balance I set up a jig & started gluing the V-tail in place...



Lots of measuring, eye-balling & more measuring...



Added a strip of heavy glass cloth...



I'll let this setup over-night, should be able to get the sub-fin on there tomorrow & finish up the glass reinforcements...

[Nodd]

Time to turn this V-tail into a Y-tail...



Added some feather-light 3/4oz glass...



Yeap that's one odd looking tail alright...



I need to mount up the ruddervators still but we have a tail... yay!

[mclarkson]

Continuing to look amazing!

[Nodd]

Airframe complete!
Time to stand back & take a look...











There's still plenty to do so back to the workshop...

[mclarkson]

Amazingly nice.

[riverrat]

Originally Posted by mclarkson

Amazingly nice.

I'll second that Mark.

Waiting for a maiden video Nodd.

Regards
Jimmy

[vicrider]

That is some fantastic work.

[JetPlaneFlyer]

Superb work, very distinctive!

Does it look like the Cg will come out ok?

Edit... I see you checked the CG... looking good!

[Yakfishingfool]

Wow!!!!

[CHELLIE]

Very Very Nice Build

[stevecooper]

Good work, and a great looker too,,, wish I'd seen your thread earlier, thanks', bubsteve

[soarrich]

Very cool. The B&W looks classy.

[Nodd]

Thanks folks. I really appreciate the kind words & encouragement. I'm pretty excited at how she's coming out. This squirrel wasn't all that impressed though...



And then I carved a bloody great gash in the side
Apparently I spaced on the need to actually control my fancy Y-tail. Some push-rods would have been nice. Oh well, too late now. Time for some minor surgery...



Glued the push-rods in place...



Replaced the fiber-glass...



And then I cut bloody great holes in the side too
Yeap more carnage. She needs to breath so I added some cooling holes...



External push-rods
Again if I'd planned ahead a little better I could have run the push-rods down inside the tail-boom but space-case here was only thinking three or four steps ahead instead of 10. The push-rods will run externally, oh well...



I used cotton thread every few inches to secure the push-rods then added a little glue to lock it in place...



Paint
A few coats of glossy Krylon & she's looking good...



Wonky servos
You'll notice my servo tray here looks a little odd...



The V-tail servos are mounted diagonally to allow the control arms to be centered away from the narrow fuselage's sides...



I also managed to squeeze the motor, ESC, SBEC & receiver in there too...



Feels good to have the radio installed. Now I need to figure out how to squeeze a LiPo in there too.

[soarrich]

I love the hard chine on the fuse. I would have just sanded it off without ever thinking about it, it really adds a distinctive look.

[Nodd]

Yeah I didn't plan on the hard chine look, the idea just came to me after staring at the partially sanded fuse late one night. Glad I took the time to stand back & look at her some.


Covering Time
My Ultracote finally arrived so time to start covering these bare-bones...



The top of the V-tail is gray. For the ruddervators I'm using transparent white...



Before you all start worrying that gray & transparent white will make her hard to see at altitude, I'll be covering the underside with black...



The black contrasts well with both blue & white sky...



I'm liking the transparent white, looks great back lit. It shows off the structure nicely without being overly see-through...



The wings will follow the same gray & white, black on the bottom format. Sounds a bit dull? Fear not, I have some colored accent graphics in mind that'll spice things up a little. I'm hoping to get the wing covered this weekend.

[mclarkson]

Originally Posted by Nodd

The V-tail servos are mounted diagonally to allow the control arms to be centered away from the narrow fuselage's sides...

Brilliant! I'm totally stealing this!

[Nodd]

Not sure how I came up with that idea. I was doing quite a bit of head scratching, trying to figure out how to mount the servos side by side & still have room for the control arms. Just about everything I tried either ran into the fuselage side or into the neighboring servo. Then it dawned on me, DIAGONAL! Eureka that works!


Control Surfaces
I picked up a set of control horns today & got down to hooking up the V-tail...



I've tried all sorts of hinging techniques, not sure if I'm just getting lazy but to be honest, good old tape rules for simplicity & functionality. Zero friction, zero hinge gap, zero fuss...



Soldering the clevises to my push-rods. What's with the towel you ask?..



Here's why we need the towel. I've had solder burn right through my covering one too many times...



A big nine foot wingspan & yet I need to make tiny fiddly little stuff like this that I can barley even see...



These small hardwood spacers keep the push-rods from flapping around, important for slop free linkages...



Yay we have a functional tail!..



Programming the V-tail mix...



I'll probably add some differential to the tail but for now I'm starting out with everything even.

And with that the tail is done...

[mclarkson]

Continues to look brilliant. And I've found Blenderm to be pretty much flawless.