abufletcher

Further thought on the number of ridges that should appear on the radiator panels. The Flight and Woodman drawings are deceptive since each line isn't a ridge. Rather alternating lines represent peaks. This is visible in the serrated lines in the flight drawings but which have been "smoothed out" in the Woodman "re-drawings." So counted this way, there would appear to be about 40 ridges per panel. This is not so terribly different from the 28 ridges of the cardboard test panel that I made.

What this means is that the lines (representing peaks) on my custom knurling wheel need to about 2.4mm apart. So 20mm wide and a pitch (is this the right word?) of around 2.5mm. No doubt a metal knurling wheel is available but I haven't yet found an online purchase source.

The first step was to grind down the "crest" on the caster wheel. Then I glued the line guide onto the wheel. Now comes the tough part, and the part I'm not sure I have the skills for, namely cutting the lines and filing them to the 90Ëš edges.

abufletcher

Hmm...my brand new razor saw hardly even scratches the plastic! Guess it's time to try the hacksaw.

Wow! The hacksaw does even LESS!

*****

OK. Interesting experiment, but that's simply not going to work. Based on what I've done so far, it would be next to impossible to get all of the grooves precisely parallel and equal width by hand. And even if I could, my tests here show that rolling the wheel (over a soft support) won't produce deep enough indentations. About all I get is something that looks like scoring marks. You actually have to press the foil down INTO the grooves with something. And if you have to do that, there's no point using the wheel.

I strongly suspect I'd have the same problem with a metal knurling wheel.

abufletcher

OK. One more...just ONE more attempt. One more crazy, last-ditch idea: Dragging a comb (maybe with some teeth removed) across foil. It either works or it doesn't and I go with the corrugated cardboard method. But this will have to wait until tomorrow.

Trev

How about crafting some kind of a negative/positive profile in metal or hard wood that could be used in a small vice to stamp out the pattern on the alu?
All you would need are 2-3 ridges (and corresponding grooves) on two opposed surfaces to get the correct spacing.
It might solve your issues with the indentation depth.

Or for a very 'low-tech' option, have you tried simply scoring the aluminium with a razor and folding over in zig-zag?

abufletcher

Yes, I believe that would work, since that's pretty much the original manufacturing process. In fact, that would be my preferred solution. But I just can't imagine any way that I could machine the two press halves. I've tried hand cuts in wood and it comes out miserably. Metal might work but I just don't think I'm capable of hand-cutting the grooves in metal with sufficient precision to get a good look.

Yep. It might work if you could be absolutely precise but I haven't been able to achieve that in the tests I did. And the chances of being able to be this precise on a minimum of 20 sheets and preferably 80 is just mind-staggering. Let's see...80 folds times 80 sheets... This looks like a job for RoboBuilder!!!

abufletcher

Each of the finished, triple-layer cardboard panels weighs 1.5g. That's another reason to go with this approach. It's really ridiculous to waste this much modeling time on something like this.

Mein Duff

I admire your determination Don.....

abufletcher

Sometimes I wish I had less determination and more good sense.

BobH

My Feedback: (2)

Don. did you know that there is corrigated metal for the train guys?

http://www.walthers.com/

GianFrancesco

Don
following the suggestion of BobH I have given a look to the web site of Brawa Modelleisenbahn; to me it seems that item 2835 Riffelblech Silber could work.............

GianFrancesco

the image I have seen is this

abufletcher

Guys, guys...

abufletcher

Time to move on. And there's still so much to do on the radiators!!! [X(] What I'm working on at the moment is the actual setup of the H-Z on my prototype #C110. As I mentioned above, looks like there are 10 panels per side (two covered) and that the panels are arranged X(?)X-X-XXX-XX-XX (the dashes represent spacers). I've modified the Flight drawings to reflect this arrangement. I also need to determine where the radiators were placed on the fuselage. This appears somewhat variable on different CI aircraft however, on the C110 the radiator appears to be roughly between the cabane struts.

PS: Mods, there's a server problem with the photo upload.

abufletcher

My modified drawing for the H-Z on C110 seems too long in my mock-up.

abufletcher

I just made a vital observation! The mid-span flying wire, which is attached to a fitting on the fuselage at the rear wing spar, passes BETWEEN two of the panels. So this absolutely dictates the position of the radiators. And the good news is that's exactly where the separation falls in my mock-up! So why does it look different in the C110 photo? [sm=72_72.gif]

abufletcher

The following image was "assembled" part by part in Photoshop from the H.Z. pieces in the original Flight drawings. Not only did this yield what I think is an accurate 1/6 scale version of the H-Z radiator that I can use to build mine, but assembling it like this also gave me a good understanding of how it all went together. The only thing that might be slightly off is that the "gaskets" I've inserted between each part, may in practice, have been compressed down much thinner. Anyway, it seems to fit well on the model.

It really is interesting the way these radiators can be adjusted to suit almost any aircraft type just by re-arranging the parts. It's like playing with LEGO!

abufletcher

Next up: Figuring the lengths for the brackets that held the radiators away from the fuselage walls. Not only were the radiator panels welded on a about 10Ëš relative to the pipes (tipping towards the rear) but the brackets were longer the back.

abufletcher

Yikes! I hate to say it, but based on the new drawings, each side of the radiator would use 61 of the flanges! So a total of 122! Looks like I'll be watching more South Park!

Mein Duff

Don.. I have in my hands.....1mm thick hard pressed cardboard sheets from some calenders I got.
These actually have corrugations within the 1 mm... believe it or not !!!
I only have two sheets about 11 x 12 " if they are any use to you? they don't have ridges of any kind on the flat surface....though maybe you could sandwich them together for the end of the radiators you need...3mm I think you said?
Anyway hope all's well..enjoying your thread as ever..
Eric aka Mein Duff

summerwind

nope........you'll continue til it's done soldier......
you are like the rest of us...........too much time into now to stop. breathers are good for the soul though, if not ones sanity

abufletcher

Thanks, but I have the 1mm corrugated cardboard from the 100 yen shop "cake pans." I think I have enough for the 60 strips I'll need for the 20 panels. The procedure is this: Soak the material in thin CA and when hardened file to create a stronger "V-shape" to the corrugations. Then cut the strips using a sharp X-acto blade (to avoid crushing the ridges). After the strips are cut to their exact size, I laminate two together ridge to ridge to create the honeycomb. Then one more layer is added "back to back" to create the ridges on both sides (4 ridge to ridge strips would be better but would be too thick). Then, the laminated panel is primed, sanded, and primed again until smooth. I may also lightly score the finished panels to simulate the effect of the "riffeln" channels. But this takes considerable care and is only visible from certain angles.

abufletcher

Or did you mean that the corrugations are spaced about 1mm (ridge to ridge)? That might be good. The stuff I have is more like 2mm spacing. But then after my analysis of the original Flight drawings, I determined that what I need is about 39 ridges over 9cm. (Hmm...just remembered something else I need to check.) With the "cake pan" materials I'm getting 28 ridges as opposed to the scale 39 ridges. That's really not bad. By comparison the knurling method creates FAR to many ridges to be scale.

abufletcher

What I meant is that watching South Park while I endlessly file flanges makes the job go a lot faster!

summerwind

abufletcher

For the 20 radiator panels, I need 60 strips of the CA-saturated 1mm corrugated paper. Yesterday, while RCU was down, I saturated the cardboard (and left the house since the CA fumes were pretty powerful). Today, I cut the strips using a "tool" made just for the purpose. This piece of wood is exactly 16.5mm wide and two strips long. So I was able to cut out 60 strips of identical width.

Next I'll need to cut each one to an exact length (1 of the 3 laminated is one ridge shorter) and then start gluing them together. Then can start the long process of filing, sanding, priming, sanding...each one. The last photo shows what the finished panel will look like.