|Sep 05, 2013, 07:11 AM|
Boeing 777-200 LR 1:44 scale (B7 project)
Hi, everyone! Serge is here and I want to share with you my project - boeing 777-200LR(ER) in 1:44 scale. I've started my project in September 2011. Two years have passed and much has been done. Now it's time to sum the interim results and share the progress. This post will be a timeline of my project. One day, one post, one big stage.
09 First steps
10 First costs
11 Laser cut
11 Plaster filler
12 Keep going
12 First vacuum
01 Technology improved
02 Wind of changes
03 Garbage day
04 First cnc results
05 Keep going
06 One small step
07 Cnc progress
08 My wings are on fire
10 Airport planning
11 Maihe: the beginning
12 A little bit of MCU
02 Lost hope
03 Keep waiting
04..06 Maihe progress
07 It's just a holiday
08 First impression
09 I'm here
|Sep 05, 2013, 06:44 PM|
09 First steps
I'd like to fly but what could I buy? At that time, a choice of rc aircraft on the market was small. I could buy a foam plane for $ 300 from south Asia or fiberglass for $ 1,000 from Hong Kong. Both variant didn't fit me.
But there was one aircraft I was admired by - plane from Australia with superb detail and unaffordable price - more then $ 3000 (price without delivery).
It was too much for me so I've started looking for what it was made of. It turned out that it is made of plastic by vacuum forming method. Thus, the question was why not try to do it yourself?
Why 777? Because she (in russian it's most common to call a plane he) he is beautiful, he has only two engines, three landing gears and the size of engines is so huge that you can scale it down to 90 mm edf without any difficulties.
My first steps were to get the 3d model of a plane. I've made it via blender and flightgear. The first variant was scaled for 70mm edf (tutorials 1,2,3). The basic concept was to do everything cheap as possible and mostly by myself. I had to divide the whole plane into many small moulds, make contours and fill a space with some kind of filler. Next step was to heat a plastic at my home oven and use some forming device - wooden box and vaccum cleaner. Hence went limits on moulds dimensions - my oven was not big. So I've received a large number of moulds. For example, the right wing was divided into 6 parts.
Well, when the overall plan had been drawn it was time to start implementing.
source: 1, 2, 3
|Sep 05, 2013, 08:30 PM|
|Sep 06, 2013, 06:19 PM|
10 First costs
Till the 7th of october the entire 3d model of B7 was made and prepared for laser cutting. Whole set of details was laid in a five big groups prepared for working table with sides of 1000 x 600mm. Overall length of cutting exceeded 150 meters. Total cost of production was about $ 300.
|Sep 07, 2013, 06:17 PM|
11 Laser cut
I took a parts from the workshop at the end of october. I got mixed feelings because I've expected a bit more quality from the laser cutting. First of all the cut is not always 90 degrees, the feeling that the laser beam is like a cone - the vertex lies on the surface, a thicker part of the reverse side cuts the workpiece. And the quality of all miscellaneous, somewhere perfect 90 degrees at the cut and somewhere noticeable tilt. It turned over four hundred parts. Imagine what kind of complexity was for producers to mess with all of this trifle. Some parts, stabilizers tips for example, have only 3.6 mm size.
Another nuance - acrylic was cut without removing the protective film. The photo shows some parts are whitish - this is burnt film film is on them and it stinks. It will be necessary to further negotiate this point with the staff shop. Their logic is clear - they want to give the customer the item is in perfect quality, no scratches. In my case it means five hours to rip off the film from all details on both sides. There is no problem where parts are big, but it's terrible where they are weeny. All fingernails were scratched. I've finished messing at 1am
Next step is to put all together, glue the stitches, pour the plaster, putty to level, smooth out surface. I figured how much time is necessary to make these master models, given my schedule. It has turned around three hundred hours, or January twelfth year, omg.
I've tried to sort it out and collect some of the details. And here, in principle, I've realized that the direction (acrylic laser-cut) choosed correctly. I have thought about when designed - may be I should do details with a gap for better assembling in mutual slots. It turned out even easier and better. When the laser cuts it makes microscopic melts. Due to this items fit like a glove.
I've gathered some parts on a table - eye beauty. Do not feel like it should be poured with plaster - so pretty without it. Tried to glue it with superglue. It turned out too fragile. Then I've tried a soft glue. The adhesive layer is obtained relatively soft and the whole construction become more reliable
Overall, despite some my grumbling, I'm happy with the result. The volume of the future work is impressive, but I'm calm, like it's said in Russia "eyes are afraid but hands do"
|Sep 08, 2013, 05:21 PM|
11 Plaster filler
6 of november I tried my technology. I decided to use a plaster putty as a filler for the first try.
For the first time it was horrible. Little pallet (size was chosen by someone's advice) is absolutely uncomfortable, plaster spreads , all is dirty , it's just ***. I rolled half a tail section and the top two quarters of the wings. I was annoyed. Something needs to change. Or technology in general or my approach.
Maybe when I will take a normal bucket instead of small pallet, everything goes well. Now in this pallet I can mix only two small portions and it's too little. As a result - just you have prepared a composition, distributed it on the form, and you have to do it again and again.
The results were so so ... adhesion was feeble, and this was expected - plastic to plaster.
Today I've tested the material which I initially expected to use - building plaster. The first impression is mixed, I add it again and again in the bucket and it not thicken. But then the error happened provoked by experience with previous material. Since originally bought the trough with a small volume, I was constantly faced with the lack of a material in the process.
Because of this, despite all I've read on the Internet about working with plaster, I mixed the material for two parts in one time. But this plaster hardens very quickly. As a result, I smeared with the palster all that is possible and even broke the part.
Ok, for now I've tested gypsum plaster, gypsum (ala alabaster), gypsum putty. Last one I liked the most.
The part is difficult today. It has a negative angle bends and even dents under the wings - I do plan to cut it off. This is the front part of the center section, the geometry itself is difficult, let's see what will happen with the plaster.
The cavity had to be filled in two stages. The first time it is necessary to put a bit of material and fill all the cavity volume. That is why the item is now looks so horrible.
About alabaster - I think it's a complete garbage. Not only it crumbles, also I’ve made a mistake. Yesterday I broke part - the outer rail. I glued it and put it down on the balcony. But there was -4 at the night and substance increased in volume and finally broke everything that I've tried to fix at evening. So I had to take a chisel and break all gypsum.
source: 1, 2, 3, 4
|Sep 09, 2013, 10:26 AM|
Awesome technique! I can't help but think that expanding foam would work well instead of the plaster though? It could be sanded to match the profiles created by the acrylic
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