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Tail Feathers Confusion

Posted: Mon Sep 10, 2018 1:14 pm
by Brian Amato
OK...maybe some of you guys who have already built your rudder, elevator, and horizontal and vertical stab can shed some light on this for me:
There are really two sources of plans to build a Piet: The old original Flying and Glider Manual and the plans Orrin drew for Bernard. I have them both. I've pored over them for years, getting ready for the day I'd actually start construction. I'm doing that now.
The tail feather drawings are confusing (at least to me) because they show the surrounding wood rabbited out to receive the 3/16 ribs. Trouble is....there are different dimensions of the sizes of those surrounds (the core size, the rabbit depth and the overall thickness and width) depending on which drawing you're looking at. Most agree with each other, but not all.
The next confusion, at least for me, is the way the plywood gussets are attached to the tail pieces. Some drawings would lead you to believe the gussets drop down INTO the rabbit making them flush with the surrounding wood and some appear to show the gusset applied ONTOP of the wood, making them proud of the structure. Go out on YouTube and look at what other guys have done and you'll see it both ways. Pull up drawings on the various Piet sites and you'll see them proud, flush, some flush and others proud....all over the map.
Does anybody feel they have the definitive answer to the correct size of the wood that makes up the structure, the actual size of the rabbit (and is it the same all the way around?) whether the gussets drop down into the recess (the rabbit) or lay proud on top and if they are flush, are they flush ALL OVER the structure or just in parts? And how the heck did you sort that out in the first place?
I'm about to go to the table saw and start ripping sitka. Who can help?
Thanks so much

Re: Tail Feathers Confusion

Posted: Mon Sep 10, 2018 6:02 pm
by danoliver
I too was very recently in your spot. My advise is to follow your interpretation of the plans and move on. In a year you'll look back and see your minor mistakes. There will be those that are acceptable and those that will need to be corrected. You'll be surprised how fixable an unfinished wooden aircraft can be.

Re: Tail Feathers Confusion

Posted: Mon Sep 10, 2018 6:58 pm
by ArthurD
I'm going to be starting the tail feathers whenever the spruce arrives. I think they probably just planted the trees when I placed the order. I'm planning to do mine flush and just have the gusset go to the edge of the beams instead of inside the lips. To get around the different thicknesses called out for the leading edge, trailing edge and main beams I'm planning to taper the beams that go between them. This is easy enough to do with a tapering jig and table saw.

Re: Tail Feathers Confusion

Posted: Tue Sep 11, 2018 6:56 am
by Brian Amato
Thanks for the feedback guys. I see I'm not the only one a bit confused by the drawings and the differences in the numbers called out in them.
3/8" on this page but 1/2" shown over there...5/8" on this one but 3/4" somewhere else.
Yes, you're right. Use my best instinct, taper where I need to and it will "all come out in the wash" as my Mother used to say.
Someone else said "you aren't building a Rolex...you're building a wooden rudder. Go for it".
Guess I will.

Re: Tail Feathers Confusion

Posted: Wed Sep 19, 2018 9:48 pm
by at7000ft
Brian

I agree with you, I thought that the wood tail was the hardest part of the plans to understand. Attached some pictures of mine that may help. I think most all of the corner gussets are inset into the rabbited side beams.

https://drive.google.com/file/d/0B1Y1jV ... sp=sharing
https://drive.google.com/file/d/0B1Y1jV ... sp=sharing

Rick H

Re: Tail Feathers Confusion

Posted: Fri Sep 21, 2018 10:10 am
by Brian Amato
Rick....beautiful work. Thanks for posting.
Brian

Re: Tail Feathers Confusion

Posted: Sat Sep 29, 2018 2:04 pm
by E.Woodson
OK, I'm pretty happy with my horizontal stabilizer....all except for the "main beam" or trailing edge. I am left with the 1/16th" lip where the gusset rests inside the main beam rabbet. I didn't want to run the gusset all the way to the trailing edge by removing the rabbet because I didn't want the trailing edge narrower by an 1/8th" (1/16th on either side) where a hinge will be installed. Here's my question. Once covered as is there would be a 1/16 " between the skin and the gusset...is this an issue? Would it be better to add 1/16th ply filler and feather it out about an inch or two and a half forward from the spot where the gusset buts against the beam? Confusing enough? Thanks for any advice...kinda don't want to reduce the width of the main beam.

Re: Tail Feathers Confusion

Posted: Sat Sep 29, 2018 5:34 pm
by E.Woodson
After pondering, smoking a pipe (tobacco), and mulling it over a nice neat bourbon, I realized the rest of the entire main beam trailing edge has that same narrowish edge, just because there is a gusset plate beneath this portion it shouldn't be any issue. I guess I was concerned with the fabric vibrating against the gusset but I'd have bigger problems if my cloth was that loose n floppy... :D

Re: Tail Feathers Confusion

Posted: Sat Sep 29, 2018 9:31 pm
by taildrags
Sounds like the prescribed medication had the desired effect. The fabric doesn't need to be glued to the gusset but can fly over it with a 1/16" cushion.

Re: Tail Feathers Confusion

Posted: Sat Sep 29, 2018 10:07 pm
by E.Woodson
Concur, thanks!!

Re: Tail Feathers Confusion

Posted: Wed Nov 21, 2018 3:02 pm
by Brian Amato
I just discovered what may be the perfect gusset material...if we even need to worry about it.
You're right: 1/8" thick gussets do drop down into the 3/16" rabbit and leave a little lip. Doesn't seem right. But then I grabbed a scrap piece of luan plywood from my scrap bin and discovered that, even tho Home Depot calls it 1/4"...it actually nets out at 3/16". Perfect down into that rabbit. Might wind up heavier back there in the tail area tho. Don't know.
All I can tell you is it fits flush as can be. And where the plans say "3/16 plyboard under fittings" this IS 3/16. Try it...see what you guys think. Post a reply too, wouldja?

Re: Tail Feathers Confusion

Posted: Thu Nov 22, 2018 3:11 pm
by EAB4
Aircraft Spruce sells 3/16 ply too

Re: Tail Feathers Confusion

Posted: Tue Dec 18, 2018 12:38 pm
by Brian Amato
at7000ft wrote:
Wed Sep 19, 2018 9:48 pm
Brian

I agree with you, I thought that the wood tail was the hardest part of the plans to understand. Attached some pictures of mine that may help. I think most all of the corner gussets are inset into the rabbited side beams.

https://drive.google.com/file/d/0B1Y1jV ... sp=sharing
https://drive.google.com/file/d/0B1Y1jV ... sp=sharing

Rick H
Rick....not sure I sufficiently thanked you for your post and the photos. I appreciate it. I agree in thinking the corner gussets are inset into the rabbited side beams. But then what did you do about the difference between the 1/8" gusset and the 3/16" rabbit? Did you sand down the 1/16" lip to bring it down to the height of the gusset (assuming you followed the plans and DID use 1/8") or leave it proud? Your photos look like it's flush. Maybe you used 3/16" gussets?
Thanx

Re: Tail Feathers Confusion

Posted: Sun Dec 23, 2018 7:22 am
by Brian Amato
One other thing (at the risk of beating this thing to death)...those of you who DID use 1/8' ply for your gussets, where'd you buy it? Did you find a big box store or some local outlet that sells 1/8 or did you have to pay the long dollar to have it shipped from A/C Spruce or the like? Any tips?
Brian

Re: Tail Feathers Confusion

Posted: Sun Dec 23, 2018 9:51 pm
by taildrags
Brian; I'm pretty sure I've seen postings from folks who have used 3mm Lauan (Philippine mahogany or meranti) as well as 1/8" mahogany door skins for making gussets. My airplane has a variety of materials in use as gussets as well as map holders and other bits here and there.

Re: Tail Feathers Confusion

Posted: Sun Dec 23, 2018 9:55 pm
by taildrags
A quick check on the internet (Ashby Lumber stores in the bay area) shows 1/8", 3'x7' mahogany door skins for fifteen bucks or so.

Re: Tail Feathers Confusion

Posted: Mon Dec 24, 2018 10:39 am
by Brian Amato
Door Skins: yup, I went to both Menards and Home Depot yesterday and they have no idea what door skins are. The closest they had was luan ply which is just under 1/4". Used as under layment mostly. Some sheets are pretty close to 3/16 but some can run thicker and stand proud of the rabbit.
Thanks guys