Re: Scratch built Sig Staggerwing build thread.. Version 3.0

[Cribbs74]

Looks good to me once the nose cone is on.

Ron

[JPvelo]

https://i.imgur.com/bZRVNdD.jpg

[JPvelo]

Probably cutting wing tips tonight. What's the best way for the grain to run?

Thank you,
Jim

[RknRusty]

If the tip is solid, I would run the grain perpendicular to the end rib.
If you make a semi-circular strip, it might be best to make a two or three piece tip with the front and back perpendicular to the end rib and the center tip-end piece parallel. I've seen kits that don't agree with this, I could be missing something, so wait for more ideas before you decide.

[Mark Boesen]

i think it depends on how thick its suppose to be, i'd probably go grain front to back, would be stronger.

[JPvelo]

Installed rib caps and center sheeting tonight. Ribs are 1/16 butted up to 1/4 triangle leading edge. 1/32 sheeting glued to face of triangle stock to form a D tube leading edge. Trailing edge is 1/32 sandwich over/under ribs. All cap strips and sheeting are 1/32.
https://i.imgur.com/4i6UFdR.jpg
Tips will be 1/16 with the grain butting perpendicular to the end ribs. All tip formers will be 1/32.

[OVERLORD]

Hello Jim,

For the wing tips, let the grain run lengthwise, parallel to the fuse as said above. Then glue a vertical gusset to reinforce. Here is a pic of the wing tip on my Jr Satan:



Lieven

[OVERLORD]

Just saw your picture of the wings, they really look great. I admire your courage and I hope I will have as much courage after 1 or more craches.

Lieven

[RknRusty]

Hmmm, I guess I was wrong. That does look right. I hope you didn't already cut them. This is what I had in mind when I said perpendicular, my Refried Bean




But here's my LJB


And my Baby Streak

[JPvelo]

Hmmm, I guess I was wrong. That does look right. I hope you didn't already cut them. This is what I had in mind when I said perpendicular, my Refried Bean

I am going with the bean option because the tips add about two inches of span on each side so the grain will run wit the longest direction of the wood. The formers should prevent chordwise warping. The bean took a pretty impact if I remember correctly, how did the tips fare?

Jim

[RknRusty]

Not a scratch on either tip. I had removed the muffler and shortened the prop not realizing it was going to suddenly be faster than I could keep up with on 40' lines, so to save myself I was doing 8's. It got behind me and when I snatched it back around the outboard wing came off. It landed 10' from the plane which came straight down under full power. A couple of ribs cracked. I need to figure out a good way to re-attach the wing.
Here she is in happier times:

[kevbo]

But here's my LJB

That is the Brodak bean, 1 peice tip of 1/8" balsa. The ol' Carl Goldberg bean had the same shape tips as the Brodak inboard, but they were laminated from two layers of 1/16" balsa. There were 3 (4 maybe??) pieces per layer with keyed joints and laid out so that the grain flowed around the shape of the tip. The joints were offset between the two layers. On the inboard tip, one layer was cut for the leadouts. They also keyed into the groove on the back of the GB leading edge. They must have been strong enough. My beans always survived crashing on grass, I only recall patching the covering and maybe gluing the fin back on. The one crash into asphalt pavement (wingover minus recovery!) didn't leave much. As a result I prefer to fly off grass. Especially my full scale glider.

[JPvelo]

Wing tips finished:
https://i.imgur.com/7J1Q2Hy.jpg
And wing strut "blanks" fitted and ready for shaping:
https://i.imgur.com/lBffkoS.jpg

[Cribbs74]

Looks good Jim. You will be flying soon.

[JPvelo]

Thanks Ron, the hard work is out of the way!

Looking for feedback on my chosen finishing method. I have been using 2 coats of Rustoleum primer followed by two Rustoleum color coats. I am skipping primer this time and using a sanding sealer made of nitrate dope and talcum powder. I already made a test patch and it came out nice. I am hoping the sealer will save weight over the primer. Any thoughts.

Thanks,
Jim

[Ken Cook]

Jim, that's pretty much a traditional base coat. Nitrate is a good choice of base due to it being almost compatible with almost every finish available. One thing to watch out for is to not spray your Rustoleum too soon over the nitrate due to the nitrate gassing off. If I can readily smell it, I consider that too soon. Another problem could be wood selection. Certain pieces aside from C-grain can warp badly if the dope isn't evenly applied to both sides due to the dope shrinking as it dries. There's taughtening and non taughtening dopes. Many of the dopes available commercially are generally taughtening meaning they continually shrink. Using full strength can certainly make matters worse. I generally go 60%/ thinner and 40% dope when using as a base. At this ratio, it takes about 4-5 coats before you get a sheen on the wood but it soaks quite well into the balsa. Warping can occur on elevator and rudder material which can go bananas over time in terms of warping. As far as weight, it certainly is much lighter than the rattle can primer. Unfortunately, it doesn't build like rattle can primer. Ken

[JPvelo]

Here's to hoping a change of color will bring a change of luck! I also made the leadouts from 27lb test braided steel saltwater leader.
https://i.imgur.com/1LDFCzJ.jpg
https://i.imgur.com/J82dkpX.jpg
https://i.imgur.com/r6BEJJi.jpg

With the dope sealer it came out significantly lighter than with rattle can primer.
Should maiden on Friday.

Jim

[RknRusty]

Alright, JP, I'll be pulling for you. Those leadouts should be bullet proof.

[Cribbs74]

Yellow is lucky! Let her rip!


Looks great BTW

[JPvelo]

Took her out and flew this morning and am not pleased with the performance. Thinned out the airfoil and loops are just big round mushy stall. I am too used to the satans performance. Will post video later but I have myself a real pretty hanger queen.
On the bright side, I started cutting wood on my next project. A real simple quick dirty build of a slab winger designed to answer a question that has been hotly debated on the forum. Stay tuned.

Jim

[RknRusty]

Jim, you could try moving the CG aft just a hair and see if it wakes up.

[duke.johnson]

I love the yellow and black. Very sharp!

[pkrankow]

Jim, you could try moving the CG aft just a hair and see if it wakes up.

Yes, you should do this.

Beautiful airplane anyways.

Phil

[JPvelo]

It turns tite, but the wing stalls bad and it's like slamming on the brakes. I need to walk away from this project for a while.

https://www.youtube.com/watch?v=vy0ur-T1_kQ&feature=youtube_gdata_player

[Mark Boesen]

idk, it doesn't look that bad...
i'd check your throws, appx. 30-35 degrees max.
open needle just a tad, it sounds like its going lean and likely your biggest problem.
Check CG
what length lines?
what prop?

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