hayofstacks

you can convert any stl file extension for 3d printing. we use replicator g, but there are many other free and low cost options available.

RepRapper

I use Freecad to draw everything, but almost any 3d cad program that can save in an STL file should work. I use ReplicatorG to run my RepRap. (Replicating Rapid Prototype). Knowing G Code will certainly help, but it really isn't nessisary. The Host software is good enough I really don't use the G Code unless I want to tweek something. The new software that I hear a lot of good things about is Pronterface. There are programs that slice your stl file and make the G code for you. I use skienforge but I have heard good thing about Slicer also. All of the programs that I use are free.

pizzano

Here's a Rep Rap that's been around for awhile now:

http://reprapbook.appspot.com/

Know I guy who has built one....but it takes alot of tweeking and constant attention to alignment adjustment....the software he prefers on his Mac is Slic3r and Pronterface 4.3...there's a newer version of it on the market.....the beta had a few bugs that have been worked out....Mac is the prefered opperating system....will work on Windows XP, Vista and 7 but your processor better be real fast and all the latest drivers operating in sync!

RepRapper

Just a few observations, first the calibration really only needs to be done once. When the machine is first set up, and it really isn't that hard.
There is another calibration that sometimes has to be done when changes to the reprap are made and that takes a minute or two and I might go weeks between having to do that.

As far as operating systems are concerned the machine itself does not need a computer at all. Most of the newer versions work with out one. I do use a computer to start my print and then I can unplug my computer completely and the Micro Processoer does the actual printing. The printer runs completely from the Ardruino and the SD card from that point on.
With a minor upgrade I wouldn't need a computer to print. I just havent done that yet simply because I have extra laptops hanging around.

Now for the software, the Reprap project was actually done on Linux and has been ported to Windows and Mac. So I guess to get the best performance you would use Linux. I am running Window XP Pro and it works fine.

As far as processor speed does not matter since it runs independently from the computer. So when it gets right down to it the Arduino does the heavy lifting so why would the processer matter on the computer? And just to fix any mis-information I am using a very old laptop. with 256 megs of ram and I think it is around 1.3 gig a hertz not a state of the art machine by any means. As far as it getting out of sync that has never happened to me at all. If I try to run it to fast and yes I did see how fast I could run it when I was setting it up. And it lost a few steps so I slowed it down a bit and since then I have had no trouble.

All in all I say 3D printing is here to stay and I think we will all own one someday.

tr4252

Thanks for explaining this; it's a very interesting subject.

Tom

solentlife

I have a large 1650mm Cessna Skylane from CMC and they basically won't sort me a replacement cowl ... I've tried to find dealers who might help .... to no avail.

So back to square one - make it myself.

This is the front end of the model showing the bare firewall ...



The smaller broken cowl on the floor is from my parkflyer Cessna 182 ... shows the size difference !!

Anyway ... I first drew round the firewall onto sheet foam as a back former ... then using scaled up measurements from the small cowl - I then worked out the reduction of size from rear to front ... the height of the prop line ... the general profile. Cut two sections of foam sheet to create a CROSS of the profile ... then added front and back ...



Marked out the front air holes and prop circle ..



Matched up to the model as a check ..



It looks a bit long ... but that is an illusion created by the profile I believe ...

Then to check that length is ok for intended power plant ... (yes it's gasoline RCGF 15cc... but the ;point is the cowl construction method).



Just about right.

Next once all glues dry .. and formers can be worked on is to sheet in 3mm cheap foam .... create the bumps and bits that all cowls have as scoops etc. and then cover in Paper Maché. Creating a shell that can then be glassed over inside and out to create a strong but as light as possible cowl.

Next instalment when that's done.

Nigel

RepRapper

I want to see if I can help make a your cowl. I have actually been having fun doing it. Not to say what you are doing will not work. As I am sure that it will. And you won't want to wait for me to make it. Still if you could send me the dimentions I would be interested in an opinion of what you think of 3D printing. Keep in mind this is an experiment and may not work. But if it does I could put the files on thingiverse or upload them to shapeways or something then the next person to need a cowl and cant find one might have a few more options. If you decide to do it this is what would I would need. Some type of outline of your firewall. What I would do is take a peice of paper and a crayon and make a rubbing. This would show me where all the holes for the motor mount need to be and the edges would help me match the fusaloge. I would also need the distance from the firewall to where the engine thrust washer would need to be, or how tall you want the cowl. I would then have you scan the firewall rubbing and send it to me. I have not tried the PLA plastic with nitro fuel yet. If you choose not to do this I understand, and will not be offended in anyway. If you are curious I think the forum would like to hear what you think when you get it. I can draw up a cowl and print it the same day. Its just not that hard. Even if it doesn't work I wont be offended. Below are some pictures of the last cowling I made just for fun it doesnt even go to anything. I was just playing around.
The cowling was made in two pieces and just stacked for the picture not glued or anything.

solentlife

Reprapper ..... thanks for the offer .... but I'm 1/2way through the construction of the base cowl and to be honest - I'm a person who likes to achieve a result.

The time factor also would be prohibitive ... as I do not live in USA etc.

Nigel

RepRapper

Just trying to help, and trying to introduce 3D printing to the hobby. Good luck with your cowl/airplane and looking good!

solentlife

I do appreciate the offer ... and I hope that 3D printing does take off ... I've followed some blogs on it but I think it early days to be a general on everyones desk facility at this time ...

Nigel

Voyager2lcats

Nigel, you and I both know someone who is a wiz at forming cowls from soda/cider bottle plastic: Barry Hardman. check out this thread; http://www.wattflyer.com/forums/showthread.php?t=36104 the last post is very informative and leads to a heat-forming thread that is brilliant. Just saying.

Bob

RepRapper

Here is another 3D printed cowl this one is for a Cessna.





and at another angle there is a smudge on one side

solentlife

Hi Bob ...

Barry and I frequently chat via email ...

The problem with the Cessna cowl I want is too big for pop-bottle forming.

But I will be looking to create new J3 Cub cowl ... which is now on it's last legs !!

Nigel

Voyager2lcats

Nigel, not to make too fine a point on this, but you can cut a bottle in half, heat form each half and add a middle section to "bridge" the gap so to speak. I have not done this, but I think it is certainly within your abilities. I know your Cessna is pretty large, but I think this method would solve your problem. You're a clever fellow, so I know you are working on a solution! Take care.

Bob

solentlife

General small cowls :

Because we fly Electric - we do not need to worry about Fuel soaking into our cowls / parts. As long as they are capable of withstanding an odd rain shower - that's good enough ....

Layers of cheapest foam you can get ... create a shape of the cowl you require. I find it best to take a C/L view and cut the required profile and then build up layers to that ...
Sand it to shape and as smooth as you can ... with water based filler to fill in the grooves / pits and dings.
Get a lollypop stick (popsicle stick you US friends call it) and glue that into the mould as a handle.
Finally a good coat of gloss paint to create a shiny gloss surface ...

But this is NOT the finished product ... this is your mould that will stay on your bench to make more cowls later if needed.

Remember I said we do not have to worry about fuel ? Think back to early school days when you made paper-mache art forms ... that's what we'll do now.

Old newspaper, trash from the office paperwork, anything that is paper and can soak up the water mix ...

We'll use PVA + water as the laminating agent. 50-50 is good enough.

First we need to apply a light smear of baby-oil to the mould - to help us remove it from the final cowl we make.

So layer up paper with PVA / water mix till you have a reasonable cowl thickness. Final layer is going to be 'Kleenex' tissue .... this is nice and fine weave to give a nice surface ... We layer it up ... let it near dry and then give another coat of PVA / Water mix to finalise the fill.

Once dry - we sand till we achieve a good finish for painting with our favourite gloss or matt paint. Ease out the mould ...

I suggest you paint inside as well ... glue plastic sheet where screws will go as support.

Viola - a cowl that is made of materials that usually you would throw away ..

Nigel

solentlife

I may have another solution to my big Cessna ... the foam carcass cowl above is near finished (I spend too much time away from home and too many projects when home to finish one !!).

Wife uses 5ltr water containers ... now they are big enough to heat-form a cowl ... so my above foam cowl allied to the sand-box might just be the answer ...
I cannot use the foam cowl with heat.

Nigel

RepRapper

I just found a cowling for an RC Cessna on "Thingiverse"



http://www.thingiverse.com/thing:1003747/#files

It would take a 3d printer to make it or you could have it done for you. To find a 3d printer in your area try

http://www.makexyz.com

RepRapper

I just found an excellent source for cowls.
http://parkflyerplastics.com/cart/in...index&cPath=55