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Old Oct 20, 2012, 02:51 PM
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Yes, I think I saw it in New Scientist on line complete with video.

They may be engineers but someone miscalculated a bit. They launched with a catapult and had barely enough speed to stay airborne. Five seconds later they were fine.

Pete
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Old Oct 21, 2012, 02:35 PM
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I owe an on topic update.

The other night I was curious to see if I could print a "traditional" rib/spar style wing in a single print.

I decided to try out some old peanut scale plans that I've tried making in balsa before but had a lot of trouble with because of the abundance of curves.

I started by pulling the plans into Sketchup. I then scaled the plans so that 1/16" on the plans was equal to about 1.2mm (double the thinnest width my extruder can make). Rather than duplicate the wing ribs from the plan, I copied the shape of the largest rib at the wing root, used the Pull tool in Sketchup to stretch that shape out to the wing tip, then scaled the wing tip to achieve a nice taper.

Then I evenly spaced out 6 1mm thick slices along the span of the wing. I then turned those slices into ribs by intersecting the slices with the original solid taper.

Since I planned on printing the wing without and rafts or supports I had to sacrifice using any spars on the upper surface of the wing. This is why you see a full height spar from top to bottom.

The photos show it freshly printed. The trailing edge is obviously too thin - my print bed is calibrated a bit too high, so the entire wing is missing it's first layer.

Other than that it didn't have any issues. The weight is 2.7g - a bit heavier than I'd like. I think that most of the weight is in the leading edge and the main spar. I could probably also get away with thinner ribs as well, but I'd want to add some gussets to increase stiffness a bit.




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Old Oct 21, 2012, 07:36 PM
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now make the other one and cover it with tissue!
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Old Oct 21, 2012, 10:48 PM
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Quote:
Originally Posted by nemoskull View Post
now make the other one and cover it with tissue!
Tissue? No, film! We're in the 21st century now.

Seriously nice work. The TE probably should be wider but aside from that it looks great.

Flew this weekend rather than worked. Hope to get my installation finalized tomorrow. I'm going to cut clearance for the extruder umbilical into the self above the printer. Once I get that done I can print the full width of the table.

Got to do more test prints and see if I can get better quality.

Pete
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Old Oct 22, 2012, 12:30 AM
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Quote:
Originally Posted by PeteSchug View Post
Tissue? No, film! We're in the 21st century now.

Seriously nice work. The TE probably should be wider but aside from that it looks great.
Thanks - I've since printed a left a right wing that are a bit lighter and stronger with better trailing and leading edges. To lighten them up I cut the rib size in half. Essentially a single extruder pass for each rib in terms of width.

I gained some strength by adding rounded gussets to every joint.

I'll take some photos before I cover them.

As much as I want to use some of my Aerolite, I'm a bit concerned about the heat. I'll need to test to see if the delicate PLA frame can handle the heat from shrinking the film.

If the PLA has issues, it'll need to be tissue.

I also started designing the fuselage. It's a lot more challenging then the wings and probably impossible to print without support material if I want to keep it lightweight.

One idea I'll try is to print the fuse with the nose pointing straight down printing an empty shell with the thinnest possible walls - no formers. By itself, that'll be heavy, but I think I can get away with printing stringers as well. When finished printing I can use a blade or a Dremel to remove material between the stringers.

That said, I'll probably start a new build thread for the next update. Keep an eye out for it.
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Old Oct 22, 2012, 12:37 AM
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Quote:
Originally Posted by PeteSchug View Post
Got to do more test prints and see if I can get better quality.
I'm not sure if the Replicator 2 uses the same motherboard as the Replicator 1, but recently I changed from the stock Makerbot Firmware to an alternative firmware called Sailfish (you'll see earlier versions of this firmware called Jetty 4, Jetty 5.5, etc).

The difference is remarkable compared to the stock firmware. Not only do prints take about a quarter of the time, the machine is more quiet, and prints are much cleaner. I spent weeks fiddling with test prints on the stock firmware. With the Sailfish firmware I printed a single test cube and was stunned at how well it turned out.

If you can't use Sailfish then I suppose slow and steady will have to do.
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Old Oct 22, 2012, 05:38 AM
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Originally Posted by elbowdonkey View Post
I'm not sure if the Replicator 2 uses the same motherboard as the Replicator 1, but recently I changed from the stock Makerbot Firmware to an alternative firmware called Sailfish (you'll see earlier versions of this firmware called Jetty 4, Jetty 5.5, etc).

The difference is remarkable compared to the stock firmware. Not only do prints take about a quarter of the time, the machine is more quiet, and prints are much cleaner. I spent weeks fiddling with test prints on the stock firmware. With the Sailfish firmware I printed a single test cube and was stunned at how well it turned out.

If you can't use Sailfish then I suppose slow and steady will have to do.
I looked at Sailfish and it doesn't mention the Replicator 2.

I'll keep an eye on it though. The last upload was fairly recent so I have to assume that if its not mentioned its because it is not yet compatable.

Running models on my Rep 2. So far I haven't successfully made one using the fine setting in MakerWare. I releveled the build table and lowered it a hair. Works okay in the other two settings.

Here's a model, recently uploaded to Thingiverse that is printed directly on tissue. Interesting idea, but not suitable for a plane like your's

Pete
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Old Oct 25, 2012, 10:38 PM
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if you took two of those wings mounted one on top of the other and added a spar, you would have a very nice symetical airfoil.
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Old Oct 25, 2012, 11:10 PM
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Interesting thought. I'd change the wings a bit since the rounded tip might not join without wrinkling tissue. The Replicator 2 table is 11 by 6 and the amount of plastic would be relatively small so the print should be pretty fast. The problem would be not introducing twist when you glue the wing halves together,

If you print on one paper for the tops and another for the bottoms you could get a twenty-two inch span with an average chord of three inches, which would be sixty-six square inches with an aspect ratio a little over seven done in two colors of tissue.

Or, it might be possible to print on Mylar. If Mylar can take the heat in stride I've got some microfilm thickness stuff around here someplace.

Sounds doable!

Pete
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Old Dec 22, 2012, 01:50 AM
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Still struggling along with this thing.

Learning a lot just running it. Spent the last two or three hours trying to print a small boat. Kept failing. I cleaned this and that, took things apart, adjusted things. No help.

I was removing the filament to adjust the plunger that presses the fil. against the drive mechanism when I found the problem

The filament is lumpy! It's garbage, full of thick and thin spots.

Swapping filaments, trying again and will visit M'bot store tomorrow to exchange filament.

Pete
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Old Dec 22, 2012, 06:10 AM
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Sorry guys, I know this is an indoor and micro airplane forum and I will use my printer for airplane parts, but I just made a decent (half way) boat hull after a bunch of failed attempts due to screwed up filament. Gotta start someplace. No, I didn't design the hull, that comes next.

Pete
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Old Dec 22, 2012, 08:59 AM
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oooh, post that in the micro boat forum! they would love that.
that is really pretty
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Old Dec 22, 2012, 09:58 AM
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I did, I posted a side view.

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Old Dec 23, 2012, 08:11 AM
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Quote:
Originally Posted by PeteSchug View Post
I looked at Sailfish and it doesn't mention the Replicator 2.

I'll keep an eye on it though. The last upload was fairly recent so I have to assume that if its not mentioned its because it is not yet compatable.

Running models on my Rep 2. So far I haven't successfully made one using the fine setting in MakerWare. I releveled the build table and lowered it a hair. Works okay in the other two settings.

Here's a model, recently uploaded to Thingiverse that is printed directly on tissue. Interesting idea, but not suitable for a plane like your's

Pete
Just FYI, if you're interested in playing with printing PLA on tissue paper, I documented my process at http://www.instructables.com/id/3D-P...-Tissue-Paper/

Andrew.
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Old Dec 23, 2012, 08:23 AM
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Thanks.

Not right now since I'm bashing my head against hardware and software at the moment, but I will take a look when I feel a bit less like I'm drowning.

Pete
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