Another Ragwing design question

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Aerowerx

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The spar carry-through from the RW8 plans...
Capture.JPGCapture1.JPG
Front view and side view.

The spar carry through is a 3/4x2 wood piece, with a 1x1x1/8 inch aluminum U channel over it. You are then to insert two AN3 bolts edge-wise through this for attaching the cabane tubes.

An AN3 bolt is 3/16 inch in diameter. That would result in the wood (on each side of the hole) being about 0.281 inches thick, or only 1.5 hole diameters.

Other than the obvious problem of making sure everything is straight before starting your drill press, are there any other potential problems with this?

I think it would be better to drill the holes through the 3/4 inch thickness, and attach the cabanes to the front of the spar carry through.
 

Chris In Marshfield

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ANC-18, p.223 and p.225 show cases where a small diameter bolt would be run across the grain near a spar fitting to help keep the spar from splitting, or use a compression bracket (for lack of a better term) wrapped around the spar for the same effect. You could probably use the latter and weld a fitting onto the bottom of it to achieve the same as what you’re drawing shows if you aren’t comfortable with drilling through the spar carry through. If you did drill it, probably want to make sure you drill it with a press or some sort of drilling jig to keep it centered like Pops did when drilling his spars.

B95935A6-A261-4424-B04C-0690A4485C9C.jpg 2DD69AF6-DBBE-4A0C-B6DD-AC3F66153BDE.jpg

It’s also mentioned in paragraph 4-83 on p.217. Doesn’t give any guidance on diameter, though.

ANC-18 link is the first sticky in the Wood section (although I’m sure you know that already :))
 

Aerowerx

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ANC-18, p.223 and p.225 show cases where a small diameter bolt would be run across the grain
If I understand the fuzzy drawing, that is essentially the same as in the drawing I posted.

You could probably use the latter and weld a fitting
No welding in this design. It is all bolted, or glued for the wood parts

if you aren’t comfortable with drilling through the spar carry through.
I have no problem drilling through the spar carry through, through the thickness. It is just drilling all the way through the 2 inches on the narrow edge.
 

Aerowerx

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Here’s the LMA example I mentioned earlier for a Super Cub replica. Borrowed from the Yahoo groups.

View attachment 71066
Hmmm. Ok. But looks a lot like a dozen other LSA size wood homebuilts. Now I have another acronym to keep track of?

I thought LMA would be a large scale RC plane.

And how do you differentiate between Light Miniature Aircraft and Large Megasize Aircraft;)?
 

poormansairforce

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Not sure I understand what you mean by introducing torsional loads. Please elaborate.
All I am saying is that it was designed it so the loads on the bolts, braces, and brackets are aligned and centered through the center line of the spar carry through. If you attach the bracing to the front face you are introducing a misalignment into the structure. If you don't add ply skins to the carry through then it may be possible to split it.
It's very possible that I'm nuts so you have been warned.
 

wsimpso1

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Why is it so many people want to deviate from the plans?

If you are trained in mechanical engineering or aero engineering with a bunch of background in structures, and you are ready to design a new plane, build it, and test fly it, then go ahead, scheme out your deviation from the plans, analyze it, build it, test it. Most folks are not prepared for that trip. For those "most folks" I advise sticking to the plans, unless there is both a known problem with the plans and a known solution to the problem. Then I advise sticking to the plans for the known solution.

Billski
 

Chris In Marshfield

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Hmmm. Ok. But looks a lot like a dozen other LSA size wood homebuilts. Now I have another acronym to keep track of?

I thought LMA would be a large scale RC plane.

And how do you differentiate between Light Miniature Aircraft and Large Megasize Aircraft;)?
It’s exactly like that :gig: The designer picked the name. I just passes along the pics.

Are there any Large Megasize Aircraft? Kit deHavilland Mosquito would qualify. How cool would that be?
 

Aerowerx

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Why is it so many people want to deviate from the plans?
I was not thinking of deviating from the plans. I was just wondering about drilling 2 inches through the 3/4 inch edge of the board, compared to drilling 3/4 inch through the 2 inch side.

Besides, if you look carefully at the front and side views there is a discrepancy as to how the cabanes are attached. The side view implies that the single cabane option is attached through the 2 inch side of the carry-through, while the front view indicates the two-cabane option is through the 3/4 inch edge. The plans refer you to "Fig 11" for the two-cabane option, which does not show how they are attached at the top, only at the firewall end.

There are so many "options" in the Ragwing plans that I find it hard to believe that all of them were designed, built, AND tested in flight.
 

pictsidhe

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It’s exactly like that :gig: The designer picked the name. I just passes along the pics.

Are there any Large Megasize Aircraft? Kit deHavilland Mosquito would qualify. How cool would that be?
Mosquitoes aren't megasize. A kit would be awesome though, I'd love one.

How about Little Megasize Aircraft? Dana mentioned a few months back that he dreamt about an ultralight spruce goose.
 

Aerowerx

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Now this is getting even more confusing.

Some pictures from Roger Mann's Photobucket page. These are all supposed to be the RW8/RW11.

R-Nose.jpg
This appears to be a single seat option. Note that there are two sets of cabanes attached to the front spar carry-through. The two attached to the center run down to the sides of the cabin. You can not see under the leading edge so I can not say how they are attached to the carry-through, but the other two run straight down to the sides in front of the instrument panel, not to the firewall. Also, the area between the panel and the firewall makes me wonder if this really is an RW8. Or does it have a bunch of builder mods?

This picture, I think, is Roger Mann's single seat prototype.
RagWing_RW8.jpg
This has a single cabane in the front, running down to the firewall, and two from the carry-through center to the sides of the cabin.

Question for everyone...Would having a cabane right in front of you be a distraction?
 

BJC

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This has a single cabane in the front, running down to the firewall, and two from the carry-through center to the sides of the cabin.
That may not be a cabane; it might be to stabilize the windshield.

Question for everyone...Would having a cabane right in front of you be a distraction?
No.


BJC
 

Aerowerx

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That may not be a cabane; it might be to stabilize the windshield.
It is definitely a cabane per the plans option.

I have been studying the plans to make sure I understand them, and then looked for construction photos to try to answer the question.

A note in the plans says that if you use two cabanes attached to the firewall that they will have to go through the windshield. Maybe that is why they attach to the side on the first picture? Then again, the plans show the single cabane attached to the middle of the firewall and the optional double cabanes attached to the top.
 

John wadman

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Now this is getting even more confusing.

Some pictures from Roger Mann's Photobucket page. These are all supposed to be the RW8/RW11.

View attachment 71089
This appears to be a single seat option. Note that there are two sets of cabanes attached to the front spar carry-through. The two attached to the center run down to the sides of the cabin. You can not see under the leading edge so I can not say how they are attached to the carry-through, but the other two run straight down to the sides in front of the instrument panel, not to the firewall. Also, the area between the panel and the firewall makes me wonder if this really is an RW8. Or does it have a bunch of builder mods?

This picture, I think, is Roger Mann's single seat prototype.
View attachment 71092
This has a single cabane in the front, running down to the firewall, and two from the carry-through center to the sides of the cabin.

Question for everyone...Would having a cabane right in front of you be a distraction?
Pietenpol aircampers and scouts were designed with an entire radiator right smack in front of you and there are many of them flying. suppose you could just always fly it in a "slip" if it bothered you. just kidding. my plane has a cabane tube right in front of me running from the front spar attachment down to the top aft side of the firewall. hasnt caused me to go crosseyed yet. you get used to it. i think my profile photo shows all 6 cabanes. see that tube running forward from front of cockpit. thats it.
 
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