Mein Duff

Ok ...what are we all voting on here?...and who's that guy eating spaghetti?...I though this was Japan?

abufletcher

I'm eating "yaki-soba" which I suppose is sort of like speghetti...if you used soy sauce and brown sugar instead of tomato sauce...and threw in some bits of cabbage and pork. And the guys are playing the Japanese group version of "rock, paper, scissors" to decide who gets to take home the leftover BBQ meat.

*****

I should have the second top panel covered tonight. Then it's on to the ailerons.

*****

At the 2:44 mark in the following video you can see some WWI vintage aerial footage of an Albatros CI crew "at work."

[youtube]http://www.youtube.com/watch?v=dwrIf_5gEEM&feature=context-vrec[/youtube]

abufletcher

Well, both top wings are covered. But I'm not a happy camper. It looks like the process managed to bow the carbon fiber LE on both panels. From the front it's straight but from above it's pulled back at least 1/4" inch...probably more. I don't think this existed before covering. I don't think this is something that can be fixed.

Note: There was no similar problem with the shorter, lower wings. I suspect it has to do with the fact that the TE doesn't go the full length of the top wings...however, the aileron cut-outs don't appear to be deformed in any way.

Note2: This is unfortunately, one of those things that could have nasty "knock-on" effects...for example, on the placement and alignment of the struts...which would in turn affect...

TFF

Cut it off and do it again. Try to creep up on the shrinking low temp to higher and stop. Do the whole wing in increments of temp.

abufletcher

I think I'd also have to be strategic about WHERE I apply the heat.

As I was just explaining to Tom in an email, the wings are still "flat" in that they haven't been bowed upwards, as is common when the top is tighten more than the bottom. My wings retain more or less the same built-in washout-twist that Chris designed into them. Remember that the wings were assembled on a glass building board with the rib elevating tabs CA'ed to the glass during construction. Rather, what has happened is that the LE is bowed backwards (that is to say, in the horizontal plane). I need to look at this more critically today and see how this was possible.

My tightening procedure was a bit complex. After getting the one-piece covering sealed to the LE, I partially tightened the bottom, then partially tightened the top. Then I attached some other areas, such as the wing tip and aileron area, then roughly tightened those areas. Then with the fabric more or less uniformly attached and with all the major wrinkles gone, I went back over for a second tightening.

abufletcher

Laid out against a large metal T-square and the edges of my building board cover, the warping seems less than it did last night. But it's still there. With the root ribs aligned parallel to the edge of the table, there is very little bowing visible on the scalloped portion of the wing. And in fact, everything is pretty much square and parallel in that area, including at the wire TE. However, at the tip of the meter-long panels, there is a measurable bowing rearwards of about 1/4 inch. I don't fully understand this as the cut-out for the aileron looks square to my eyes, measured against a small triangle. (You need to ignore some of the distortion introduced through the photography).

Cutting off and starting again is an option...one that would, however, require ordering more fabric thereby delaying the process by a month. The good news (or the "less bad news") is that both panels seem to be more or less the same.

Mein Duff

That is good news that they are both of equal bowing ....Probably irritating right now but probably less bothersome later... doubt any body would notice unless you pointed it out to them when it's all together.. The thought of redoing it for that little bend is indeed disheartening[]

abufletcher

Tom has found a way for me to save face despite those bowed leading edges! He points out that according to the datafile the wings were actually slanted back 1.7Ëš so I should be able to "hide" the fact.

Flying Fox

Now, that was very scary to read.
When I first read it I thought you were in serious trouble and would have to strip the covering...
It's always a huge scare when some kind of unexpected error creeps into the system so late in the build. Looks now like you will be okay with it though and able to disguise the mishap nicely into the swept wing effect. To your critical eye it will always be there but to the rest of us it will not be seen and so in effect be 'corrected'. I guess you will have to adjust the allignment and maybe the length of the outer interplane struts but that shouldn't be too big a problem.

It is kind of wierd to try to understand how this occured, have the ribs buckled or bent somewhat, perpendicular to the leading edge, as you move out to the wing tips?

Looks like you are going to be okay though!

Bri

abufletcher

Yes, I think I'm going to have to "finesse" the alignment of the four wing panels and hopefully I won't have to do anything to the struts. We'll see.

I'm also trying to understand this. First, I checked to see if the "missing TE" was the cause, so I measured the distances from the front of the root rib to the rib at the aileron cutout. Then I checked the same (from the rear of the root rib to the same rib on the TE) and, while it is 1/16" shorter, I don't think this in itself is enough to explain the 1/4" of bowing. Because I used hardwood diagonals and ply gussets to reinforce the ribs holding the ends of the TE wire, not much movement was possible so the TE held up reasonable well during the shrinkage. Second, I looked at the area of the wing with the aileron cut-out. The bowing doesn't seem any more pronounced in this area. So I think it's just a cumulative effect over the entire LE, not enough to be noticeable to the eye at any one rib. I've mounted one of the ailerons and it seems to fit just fine, with the hinge holes aligning perfectly with the previously drilled locations.

It may have been better, back when I was building the wings, to use 3mm CF rod instead of 3mm CF tube. (And, you know, I'm not absolutely certain, that there was no bowing BEFORE covering. Maybe I only just now noticed it.)

fliegertom

Hallo Don,

Alles wird gut....mach weiter so!

Tom

TFF

I think what did it was the cord change the ribs have at the ailerons. lightweight structure with size change and strong shrinking ability. Dacron for airplanes can shrink 6" over a 10' span; that is a lot of shrink.

abufletcher

I'm sure you're right. I suppose I could have used Solartex Natural on the outboard portion of the panels...but it's already been a very complex covering process...especially for my first time using Koverall. I still haven't mastered the details. Also, on the topic of Stix-it vs. dope, I'd say that the Stix-it was good for some things and not do good for others. At some stages it was nice to use the iron to "melt" the already applied and dried Stix-it. But the Stix-it doesn't seem to stick as strongly as dope...or maybe I didn't lay down thin enough coats before attaching. What is nice about the Stix-it is that it sticks more or less immediately, while the dope doesn't hold things in place until the dope dries. Anyway, it's all a learning process and I guess I would use both products again for the right job.

abufletcher

[PHOTO UPLOAD NOT WORKING, AGAIN]

abufletcher

I'm done with the Koverall part of the covering and it's nice to see the CI with its wings. I think I'll move on to covering the ailerons, fin/rudder, stab/elevators before I proceed with the next steps on the wings. In the second photo the LE bowing is exaggerated both by the downward hang of the unsupported wing and the effect of the camera lens. It looks quite unsightly in the photo, but should be better when all the struts and rigging is done.

Before I can cover the tail surfaces, I need to finish some construction details (as with the wings). I need to make and add some scale control horns and also finalize the attachment points for the supporting braces. I won't be using Koverall on the flight surfaces. It would almost certainly crush them. So instead I'll using either Solartex Natural or perhaps Polyspan (if I have enough to do the job). These will also get the silk treatment.

TFF

The trailing edge looks good.

Flying Fox

Yes the trailing edge looks fantastic! Maybe show us a closeup of just a few bays of the TE
1st photo really shows of the plane well.

I'm just going to ignore your 'bad' photo of a good thing!

Bri

abufletcher

The problem is that I really like this perspective/angle on the model so I hope the LE "bump" becomes less noticeable. [:'(]

abufletcher

Bri, here's that close-up photo you requested. I'm happy with how it looks but being perfect honest with myself it's off in two ways. First the scallops are too deep. They look neat and most people who see the model are going to think this looks neat. But on the original the scallops were much less pronounced. If I were to do this all over again (or if I were to decide to recover the wings), I would just use a straight wire (or cable) for the TE and let the Koverall do its thing. Pre-curving the aluminum soldering wire created too much curve. Even solartex might have had enough pull to the shallower scallops. Second, the tips of the ribs and my wire attachment points are unrealistically wide. The tips should be sharp points, not flat areas. Partly, this is the "non-scale knock-on effect" I'm always talking about. The ribs aren't scale thickness so the rib caps aren't scale thickness, so the rib tips aren't scale.

And, yes, just using the kit's ply TE with the scallops would actually a have been more accurate in terms of the depth of the scallops...but I figured I might only have this one opportunity to build a wing with a scalloped edge so I just couldn't pass on the chance to try one. And I'm glad I did it.

abufletcher

Each step forward brings with it a new set of questions, challenges, and problems. For now, I'm going to avoid the new issues with the wings (spacing of the panels, alignment of the struts, etc.) by working on the tail feathers. That should be fairly easy.

Nieuport nut

My Feedback: (10)

It may not be perfect but you are your own greatest critic!

I have thought about how to do scallops often, over the years, and following the original method has always seemed the best route. Perhaps the flat "points" are too wide, and maybe the scallops are a little deep, but the overall effect is terrific. Just think how good a job you can do on your next scalloped wing!

Martin

Teus

I agree with Martin,

It looks terrific Don [8D]

abufletcher

As I said, it's one of those things that everyone, even other scale modelers, is going to say looks great...partly because it's a feature we all like to see on WWI models. It's a "fun" feature and one that seems natural to exaggerate a bit, maybe like the exaggerated "pre-shading" that WWII modelers sometime use on panel lines. But it just doesn't match the photos or 3-views. The original "scalloping" (as an incidental feature) was very subtle and from a distance the TE looks essentially straight. But it would be really rather obsessively crazy to decide to redo it at this stage. As Martin says I'll just have to wait for when or if I do another scalloped wire TE. Of course, the Strutter had a "wire" edge but it was apparently rigid enough not to allow any scallop.

GianFrancesco

Hi Don
..... the Strutter had a ''wire'' edge but it was apparently rigid enough not to allow any scallop. [/quote]
The Strutter TE was made by a A&P No.121 oval steel tube; therefore no scallops on it!

abufletcher

First details on the tail feathers. First I added a scale flange at the front tip of the fin. This mirrors the two similar flanges on the stab tips. On the stab these flanges also allowed the incidence of the stab to be adjusted on the ground by attaching this flange to one of three bolts on the fuselage side. I've placed the top bolt at the same location that Chris' design has the stab tip because I didn't want to be messing with the basics of his decalage. In the DF photos the stab seems to be located most of the time on the top bolt, occasionally on the middle one, and never on the bottom one.

I'm also wondering about the size of the control horns provided with the kit. The rudder horn is approximately the right scale size. It's operated by a somewhat complex multi-bellcrank steup in the front. But the elevator horns seem way too big. The scale horns are about the size of the rudder horn and even from a modeling perspective the horns are much larger than the arms on the bellcranks operating them.