Ragwing RW4 build

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Aerowerx

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This is my start-over project.

I will be building a Ragwing RW4 like this:

RagWingRW4.jpg

I have been contemplating a couple of cosmetic changes, like a taller turtle deck and a sliding canopy. Otherwise it will be per the plans. Although there are so many 'options' in the plans that it seems strange to still call it a RW4.

I also am still pondering the landing gear. The spoke wheels look classic, but I already have brakes and axles that fit on Azusa wheels. There are also several options in the plans for the landing gear struts.

Power will be my 4A084 engine, and one of the options in the plans is a stretch fuselage to handle the larger engine. With the 40 hp engine and 600 lb gross, it should be pretty close to the performance of the original classics from the 1930s.

Today I actually did get started on the project. After cleaning up the Flugzeugfabrik a bit, I made a mess again by turning a length of 0.90 inch Douglas Fir into a length of 0.75 inch Douglas Fir.
 

Aerowerx

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I should have pointed out that the Ragwing designs use almost exclusively 3/4 inch stock. Here in the USA that is a standard lumber dimension, so theoretically you could go to a lumber yard and buy your wood off the shelf---assuming you can find some that met the 'straight grain' requirements.

I have carefully compared the Ragwing and Minimax designs. They are virtually identical in construction. The Minimax, however, uses wood thickness tailored for the particular component. So if you mill or buy your own wood, the Ragwing would be easier---only one size to keep track of. With the Minimax the advantage goes to the wood kits they supply, unless you want to do a lot of extra work milling all those sizes.
 

Aerowerx

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Today I turned the 8 inch wide Douglas Fir into 3/4 inch strips.

This is my set up:
IMG_20160525_143427885_HDR.jpg
I made up another 15 foot 220v extension cord so I could move my saw to the end of the table. It makes it a lot easier having to handle only one end of a 16 foot board!

There's a fuselage in there some where. Can you see it?
IMG_20160525_143439074_HDR.jpg
I cut 6 pieces, 3/4 inch wide. What I am finding is that it is difficult to get better than+/-0.02 inch when handling a large piece like this. But I want to leave them the full 16 foot until I know I need shorter pieces.

What I do is look at the grain, which is never the same spacing all the way across the board, and start cutting from the edge with the tighest grain, leaving the wider grain for the wider pieces that will be needed.

Now this should impress you. I know I was:
IMG_20160525_140018398.jpgIMG_20160525_144238872_HDR.jpg
When I was truing up the edge, this is what came off. It is a single grain line, about 1/16th inch wide. It would have remained the full 16 foot, except it broke at a small knot. How's that for a straight grain!


Pictures taken with my cell phone, since my camera was stolen by a druggy!:mad2:

By the way, I have 2 weeks off right now, 16 days if you count weekends. So barring an unexpected attack by Real Life, I hope to get a good start on assembling the fuselage.

The next step is to lay out the fuselage jig on the build table.
 

Aerowerx

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After yesterday's post, I went back out after supper and laid out the fuselage side outline.

Didn't get much done today, due to a slight bought with Real Life. (Had to drive to Toledo and back. If you haven't been in the area lately, there is a continuous 50 mile construction zone on I-75.)

After the trip I did spend some time at the table saw. Yesterday, I had overlooked that the empenage required some 1/2 by 3/4 inch for the diagonal braces, so I ripped the remainder of the Douglas Fir from yesterday. Ended up with 7. More than I need for the fuselage, probably, but there was just about 5/8 inch left so I went ahead and cut it to 1/2 inch. It will all get used somewhere.

Needless to say, I am exhausted today.

Tomorrow I plan on putting the jig blocks on the fuselage layout, and hopefully start cutting pieces to fit.

Oh, almost forgot. There are some 3/4 by 1-1/2 inch pieces needed around the firewall, so I will have to mill and cut those.
 

Aerowerx

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Some good progress today!

Installed the jig blocks for the top longeron and bottom rear longeron:
IMG_20160527_152400205_HDR.jpg

By the way, the white stuff is where I painted over some old lines, so I would not get confused.

The blocks are left over from my earlier J-1T project. They are made from an old 2x4, and sanded square on one side. The neat little clamps I found at the 'clearance table' at Menard's, so I bought them out!
IMG_20160527_152416038_HDR.jpg

Hmmm. I had some more pictures to show you, but they seem to have disappeared. Something to do with downloading them from my smart phone to my laptop makes them blank.

Anyway...

I said in an earlier post that I was going to build per plans. That isn't quite so... So I confess that I am making one minor change. Per the plans there is a 'natural bend' in the bottom longeron. Since I am paranoid about compound curves after my experience with my J-1T, I decided to do it a different way. If you look at the Minimax design, you will see two scarf joints on the bottom longeron, under the cockpit area, so I am going to do it that way. It will allow the longeron under the cockpit to be straight. This is good since the cockpit floor will be 1/4 inch plywood, which will be hard to bend on a 'natural curve'. This requires some careful cutting and fitting, so I came up with this set up:
IMG_20160527_181829566_HDR.jpg

The angle required is 8.6 degrees, measured with a digital protractor. I was going to show you how it came out, but that is in the missing pictures. You will have to wait until tomorrow, folks.

I did get all the longeron pieces for one side done and put in the jig, and then started on the other side. Everything was fine until I did the second scarf piece. Instead of starting from the beginning, I used the first piece to set up the scarfing jig---bad idea. At that time I decided I was getting tired, and that was enough for the day.
 

Aerowerx

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More good progress today.

I got all the vertical and diagonal truss pieces cut, about 1/8th inch too long. Here they are in their respective locations:
080.jpg

Then I made this jig:
077.jpg
The angle matches the angle between the bottom longeron and the vertical trusses: 98.6 degrees.

Here is how it is used, to set the miter gauge on the table saw:
083.jpg
Place the beveled edge against the saw blade, and adjust the miter gauge to match.

This makes it easier to cut the bevel in all the vertical trusses:
081.jpg

And then I trimmed them to length for a snug, but not tight, fit:
082.jpg

Now, this is the problem area I was talking about in my last update:
063.jpg
This is at the floor of the cockpit area. There is a scarf joint at each end of the longeron. For the first one I carefully measured everything and it came out perfect. Then I used the first one as a gauge to make the second. Not a good idea. I will have to make it over using the jig described above.

The next task is to precisely locate the vertical truss pieces, and then bevel and trim the diagonals, after which I will be ready for some T-88!:ban:
 

Aerowerx

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I didn't make a post yesterday, but this is what I did...

I cut a new cockpit-bottom longeron, and beveled the edges using the same procedure as for the first one. Fits pretty good:
001.jpg

The plans give the locations of the vertical truss pieces as their center line. This means that when you put the piece in place you are covering up the location mark. So I transferred the mark to the top of the longerons, and marked the center line of each piece, like this:
002.jpg003.jpg004.jpg

Then today, the diagonal pieces.....

Every one is a different length and requires a different bevel angle at each end (except for those in the 2nd bay which has square corners).

I had forgot I had this thing stuck in my 'measure&mark drawer':
006.jpg
It certainly would have made things a lot easier on that cockpit bottom longeron.

As shown, I used it to measure the angle of the bevel required, then directly transferred it to the table saw miter gauge:
005.jpg

As I did each piece I labeled it so I could be sure of getting it back in the correct location. Turns out that this would not have been necessary, as each one only fits in one place after beveling.
007.jpg

Beveling all the diagonals took about 6 hours all together since, as I mentioned above, each end of each piece was different and had to be measured and fitted individually. I ran into a problem with the last two bays. There was no more adjustment on the miter gauge, so I had to modify the method slightly, with the previously described angle jig:
009.jpg
This is a potentially hazardous way to do it. Fortunately, I still have all my fingers.:)

And, here they are all trimmed to fit and in place:
010.jpg011.jpg

You may have noticed that I am cutting and fitting the pieces for both sides at the same time. The jig is also set up so that I can epoxy one side, and them immediately epoxy the other side without having to wait (with appropriate anti-stick tape in between the two, of course).

I have one more piece to do in the front bay, and then I will be ready for the T-88.
 

Aerowerx

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I believe in admitting your mistakes, learning from them, and moving on. So....

I goofed.

Yesterday I had to mill another piece of Douglas Fir but got a little too aggresive with the power surface planer. It came out as 0.70 inches thick, instead of 0.75.

The plans call for Northern White Pine, so I checked the mechanical properties. Even being slightly under sized, the Douglas Fir will still be a lot stronger than either Sitka Spruce or White Pine.

The pieces I cut are mainly for the horizontal trusses, and I will just have to be careful how I orient them so the thickness will match (I ripped them lengthwise to the correct dimension). And I still have a bunch of the 0.50x0.75 inch for the more diagonal truss pieces.

I still have one 16 ft x 8 inch board left, which I am hoping will be enough for the wing.
 

Aerowerx

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When going over the plans today, I noticed I had overlooked these little blocks:
004 (2).jpg
They accept the bolts that will secure the horizontal tail.

I then finished the first bay by adding the (split) diagonal.
002 (2).jpg

Then installed the seat supports.
003 (2).jpg
The gently sloped part will support the seat bottom. For the short vertical pieces there will be some short plywood bulkheads, that not only support the seat but also serve as the bearing surfaces for the aileron torque tube. The plans call for 1/4 inch plywood bearings:ermm:, but I think I will use some Delrin instead.

I thought I got a picture of it, but I guess I didn't. Not shown is the seat back supports, which run from the 3-point junction up to the top longeron, just ahead of the rear spar carry-through. The plans are a little unclear about this. There are two conflicting drawings. One shows a hinged seat back to gain access to the back of the seat. The other has a solidly attached seat back that acts as a bulkhead.

One concern is that the Ragwing plans do not specify where the seat belt should be attached. The Minimax has a small block stuck to the lower longeron. I will have to ponder this a bit.
 

Aerowerx

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Didn't get as much done today as I had hoped. Better Half had a "procedure" done today, in Toledo. So that meant getting up at 6am, and a 2 hour drive each way.:tired::tired::tired::tired::tired:

I finished up the seat area. This time I got a picture with the seat back support, and the picture is in the proper orientation (toward you in the picture is the bottom of the fuselage).
001.jpg
There are a lot of pieces and joints there, and I don't particularly care for it. But that is what is in the plans. I kept what I think is the most critical part, the long diagonal between the top and bottom longerons, in one piece, and split the seat support as shown. The plans are a bit unclear in this area, and the part 103 version is different from the stretch version I am building.

I had mentioned in the previous post about the seatbelt attachment not being mentioned in the Ragwing plans. I looked at what the Minimax does, and decided to copy it.
002.jpg
If you compare this picture with one from the previous post, you will see that I replaced the 0.75x0.75 inch piece with a 1.5x0.75 inch. This is where the seat belt will attach.
 

Aerowerx

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Some one had sent me a private message, indicating some concern over the quality of wood I am using. So here are a few pictures of a sample to put everyone's mind at ease:
001.jpg002.jpg003.jpg
This is certainly not the best piece I have, with regard to the grain spacing. I think what he was seeing was the dark spots on the edge, as can be seen on this piece. It is hard to feed a 16 foot board through a table saw at a constant rate, and if it pauses (board, not saw) for a few seconds sometimes the wood will rub on the saw blade making the dark spots. This is just on the surface and does not affect the properties of the wood at all.

Today's progress...

I know I took more pictures of the intermediate steps, but my cell phone camera played tricks on me again---some of the pictures dissappeared. So I had to go back out and take a couple of the end result.

Here I have removed everything from the jig, and put some shiny plastic tape on the table at all the joints, and then put the pieces for one side back in the jig:
004.jpg005.jpg

And here is the result...Both sides glued up and clamped:
006.jpg

What I had done was put some more tape on the joints in the first side, and then glued up the second side, so both can cure at the same time:
007.jpg

The temperature in the Flugzeugfabrik was about 85 degrees today, and it will get down to about 70 tonight and back up to 80 tomorrow, so the T-88 should be set enough for me to remove the sides from the jig by noon tomorrow.
 

Aerowerx

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Didn't get as much done today as I had planned, due to a small episode with Real Life.

Here are the sides removed from the jig:
001.jpg

For the most part, it looks good. There are maybe 3 or 4 joints that I don't like, and will have to fix. I'm not sure what went wrong with them. Probably inadequate clamping, and the epoxy ran out before it gelled.

Then I cleaned up the joints, removing the excess epoxy that squeezed (or flowed) out.
002.jpg

Trying the plywood skin for size...
003.jpg

I then traced around all the truss members...
004.jpg

Then I scuffed up the ply between the lines, and lightly sanded the Douglas Fir (recommended by System 3). And used a wet rag to wipe off the sawdust.

Here it is, all glued up...
007.jpg

The plans have you turn the whole thing over and staple the plywood to the longerons and trusses. I find it easier to do it this way, and it is not as messy with the epoxy. Just keep adding weight until you can no longer see any flexing (flexing can be seen by pushing on the wood and watching for epoxy squeezing out---just add more weight in that area).

Hard to see, but there is a smaller piece of ply at the tail end.

I had planned on doing the ply on both sides, but I was getting tired and thought that was a good stopping point.

The plans have the option of using normal gussetts, or running a continuous narrow strip down the entire length of the longerons, between the front ply and tail-end ply. Still pondering that.
 

Aerowerx

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I was only able to spend about 2 hours on the project, so not much to report.

The "stretch option" specifies gusset strips instead of normal gussets. I don't know why it would make much difference either way (except weight), but I went ahead and cut them anyway:
001.jpg

And here they are, all glued up:
002.jpg
This is the left side of the fuselage.

And here is what I had planned on, but didn't get to...the right side skins and gussets:
003.jpg
 

Aerowerx

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Got a late start today again. Only got in about 2.5 hours, but things are shaping up.

I trimmed the excess plywood using my router with an edge trimming bit.
002.jpg

Does a neat job, doesn't it? Except...

I thought I had fixed it, but my Sears POS router tends to walk the bits out when working on thicker wood, even though the edge trimmer bit is 1 inch long.

This is what happened when trimming the excess around the scarf joints:
003.jpg005.jpg
I am more disgusted with myself than concerned.:emb: There will be a 1/8th inch gusset plate on the inside of this point, and the bottom of the cockpit will be 3/32 inch. I can also fill it with a saw dust/epoxy slurry. There will be plenty of support in this area. No one will know it is there, except myself. I could rip it apart and redo this section, but that would probably do far more harm.

So why didn't I think of this earlier? Just use my table saw to trim the stubs off the scarf joints!

And this is how it worked out:
004.jpg

And here is the right side, with the gusset strips all glued up.
006.jpg

My marathon build session is coming to a close. One more day and I have to go back to work:cry::depressed. I just might make my goal on this part of my build, which I will reveal tomorrow one way or the other.
 

Aerowerx

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Well, I didn't make it to my goal, but close.

I am satisfied with the results so far, and did make a lot of progress in my Marathon build spree.

Today I cleaned up the excess epoxy on the gusset strips, and then started setting up the jig blocks for assembling the fuselage:
001.jpg002.jpg003.jpg
This is a dry fit---no epoxy yet.

I also did a "trial bend" to see how easy it would be to bring the tail end together. It is a lot easier than I thought it would be.
004.jpg005.jpg007.jpg008.jpg

And a side view:
009.jpg

The thing is remarkably sturdy with just the clamps and a few jig blocks holding it together. It certainly looks stronger than my previous J-1T project.

My goal was to get the cross pieces in the nose and cockpit area glued up, but as I was doing the above I realized I was getting tired and there is a lot of things to verify and cross check before mixing more T-88. I thought it better to stop before I really made a mess of things.

I also want to sit in the thing to get an idea of how much room I will have. I may be able to make it narrower. Right now it is 24 inches inside, between the longerons. 22 inches would be nice, if it isn't too crowded. Additionally, I might try pulling the nose in a bit as is done on the Minimax. This would give it a more streamlined look.

There are also a number of inside gussets needed in the cockpit area, and they might be easier to put in with the sides laying flat.

This is the last few hours of my vacation. Tomorrow it is back to work:cry::depressed:cry::depressed:cry::depressed. Progress will be a lot slower from now on.
 

Aerowerx

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When I got home from work tonight, I went out and tried the fuselage on for size.

I think I will leave it at 24 inches inside width. With my arms in a relaxed position and my elbows bent (as if I had a hand on the side-mounted throttle), my elbows just clear the truss structure. If I make it narrower I think it would be too cramped, particularly in cool weather with a heavy jacket on.




I also received a PM from another HBA member, asking if the tail-end pieces should be beveled. The plans do not mention that, but I think it would be a good idea.

The first problem, though, is that the two sides are not the same length. I'm not sure how it happened, but one side is about 1/4 inch longer. It may be because I did not like the joints on those small vertical truss pieces (and they did come apart during handling), and re-epoxied them when I was putting the skins on. I guess I got them slightly out of alignment:
001.jpg
They will have to be trimmed. From what I have read, and from working with the stuff, Douglas Fir does not do well with hand tools, and I can do a neater job on my table saw anyway, so I will have to build a sled for the saw that can hold the fuselage sides while cross cutting.

So, how to get the proper bevel angle? The easiest way, I think, is to use my miter gauge like this:
002.jpg
This picture is for illustrating the concept only. When doing it for real I will first trim the sides to the same length, and then make sure that the ruler part of the gauge is perpendicular to the center line of the fuselage (marked on the table---not visible in the picture). Then it is a simple matter to transfer the angle to the table saw. With the sides flat on the table it should come out just right.

I will have to make 2 cuts. One with the measured angle to get the ends perpendicular to the center line, and a second with the compliment (90 degrees minus the angle) so the ends will contact each other at something other than a sharp corner. This is a case where a picture is easier than explaining it, so you will have to wait until I do it.

Another method is to do it like on the Minimax. On the Minimax the two sides do not come together at a point. Rather there is a solid piece of wood between them. This then has a hole for the elevator push-rod. I would not have to make it as wide. An inch or two would do, since on the Ragwing the elevator push-rod comes out the side below the h-stab. Again, a picture is easier than describing it.
 

Aerowerx

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Just got back from another drive to Toledo. Better Half's specialist Dr. is there. Had to get up at 7AM, and am tired. I think I will spend a bit of time figuring which end is up, and then head out to the Flugzeugfabrik. Meanwhile...

From some of the other threads here in HBA, you may have seen that I am concerned about the lack of smaller size 6061 aluminum channel.

What I mainly need it for is the landing gear attachment to the fuselage bottom.

I could place a custom order for several hundred feet, or...

One option is to use 2 sections of aluminum "L" angle, one facing forwards and one backwards. The landing gear struts would then be bolted in between the two.

Another option is to use square tubing. But the problem with this is the tolerance on the dimensions. With a 1.25 inch square tube x 0.125 wall thickness, just what is the inside dimension? I will need to trim one side and insert the 1 inch OD gear struts. Will it fit? I doubt it, unless I happen to get lucky with the tolerances (or squash the end of the tubing, which I don't like.)

There are still a few places where a channel is called for, but using two angle pieces won't fit nicely. I'm still thinking about those.

It still bothers me that there are all those plans out there that call out smaller size U channels, when the stuff isn't available.
 

Aerowerx

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I did get a little bit done today.

First, I went over all the joints with a small magnifying glass.
005.jpg
This happens to show a good joint.

Then put on some "dikes", made of shiny packing tape.
006.jpg

Finally, mixed up some T-88 and tried to force it into the gaps. I also slopped enough on top so it would flow down into the gap.
007.jpg

I had enough T-88 mixed up that I went ahead and glued up my cross-cut sled.
008.jpg009.jpg
This will allow me to cut larger pieces accurately. It is hard to see in these pictures, being weighed down with the old cans of paint, but those long narrow pieces run in the miter slots on the table. There is one piece not shown here. That is the fence, which I haven't cut yet. It will have to be precisely aligned at a right angle to the blade.
 

Aerowerx

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No pictures today. My cell phone is not charging for some reason.

I did try it on for size again (fuselage, not cell phone:gig:).

This time I took careful measurements. 24 inches inside is plenty of room, and gave about 1.5 inches of elbow room with my arms resting on my knees. I tried 21 inches, and that would work, but I think it would be more enjoyable with 22 inches inside width.
 

Aerowerx

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Recently, I have only been able to spend a couple of hours a week on the project.

Most of that time has been spent working on a cross-cut sled for my table saw. Here it is under construction:
006.jpg
This will allow me to cut larger pieces that are too big for the miter gauge that came with the saw.

I did get this thing off of Amazon.com:
017.jpg015.jpg
It will help me drill holes in things that are too big or clumsy to fit on my table-top sized drill press.

This is how it works:
018.jpg
It can also be adjusted to drill holes at an angle, and can also be used with hole saws up to about 3 inches in diameter, which is why I got this particular one.

The first thing I used this for was drilling a pilot hole (yes, that is a pun:)) in the seat belt attachment block:
021.jpg
Why did I do this? Because there is going to be a gusset placed over this area, and then I would be unable to locate the center of the block.

Speaking of hole saws, I also picked this up on sale at Harbor Freight:
024.jpg
There are 13 sizes from 3/4 inch to 5 inch diameter. The 5 inch is big enough for an inspection plate.
 
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