Welcome back for part three of the Me-109 construction series. In part two, we finished the plug. In this article, we will cover:
Before I get started, I would like to apologize for the delay in getting this article out. My wife recently had a baby and after that, my building time went almost to zero.
Before getting started on the mold, I waxed the plug 5 or 6 times with Part All. This helps to keep the resin from sticking to the plug just in case the PVA gets torn during layup.
Because the wing fillets come out to a thin edge, I wanted the mold to have a removable section for the bottom of the wing saddle. This would help with getting the parts out without breaking them. The mold would need a flange around that area so that the pieces could be clamped together, so I built a jig to support some clay and formed the flange up out of the clay. I also built flanges out of ¼" hardboard for the front and back of the removable saddle section.
I coated the area with tooling resin. This is a mix of epoxy, graphite powder and Cabosil. The tooling resin should be about like honey - just thin enough to flow so that air bubbles can float to the surface. The graphite powder just makes it black so that it is easier to see air bubbles when laying up the parts. After the tooling coat kicked, I laid up two layers of 3oz cloth, two layers of 17oz knitted double bias cloth, then one last layer of 3oz cloth to give the surface a smooth surface for handling purposes. The knitted double bias cloth forms around curved surfaces very easily and helps to bulk up the mold quickly.
Next comes the parting board. As you can see, I added some supports to keep the plug in the right position while claying.
I stuffed clay into the gap on the backside to help hold the plug, then filled in the gap on the front side and scraped away the excess with a razor blade.
I covered the particleboard with some shiny plastic tape just to give the parting board a smooth surface, then I sprayed the whole thing with PVA.
I laid up the first mold half in the same manner as the wing saddle.
I let the first half cure for a day, and then removed the parting board. I cleaned off the clay, and then used a 3/8" drill to make alignment buttons in the flange. These are not drilled through, just enough to make an indentation. The resin will form into these when the second half of the mold is laid up. Then I waxed the mold flange with Part All, and sprayed the whole thing with PVA. The second half of the mold was then laid up in the same way.
The next day came the moment of truth. I trimmed the flange with a jigsaw in preparation for parting the mold. Then using a couple of screwdrivers, I carefully worked my way around the flange, popping it loose. A few minutes later, the plug was out. Woohooo!!
Now that the mold is finished, it is time to make a part! My friend Vic Catalasan came by and helped me with laying up a part. We first waxed the mold with Part All and then sprayed it with PVA. Next, we mixed some epoxy and Cabosil and used that to fill the wing fillets, exhaust pipes, all the little scoops and any place where there were sharp corners such as the canopy.
We then laid up three layers of 6oz cloth.
To seam the fuselage in the mold, we left the glass long along opposing edges and trimmed the other edges. I have a better picture of this later in the supercharger intake section. We then aligned the mold halves and clamped them together. Once everything was clamped up, we reached in through the access holes and dabbed the seam down with an acid brush taped to the end of a stick.clamped.jpg
Here is the first part out of the mold.
The supercharger intake was made the same way. Here are a couple of shots. Notice how the glass has been trimmed and left long on opposing edges. This makes it easier to put the two mold halves together without disturbing the layup.
In order to keep the article reasonably short, I will not go into a lot of detail on the building of the wing and horizontal. I had these pieces ready to go by the time the mold was finished.
Another friend of mine told me that he uses Goop to hold his wings on, so I decided to try it on this plane. I had to let it dry over night, but it stuck very well. I just touched up around the wing fillet with a little lightweight body filler. The horizontal is glued in with 5-minute epoxy and Cabosil.
To mount the radio gear I made a servo tray so that I could mount the elevator servo up on blocks so that the pushrod would clear the aileron linkage.
I still needed to make the heat shield over the exhaust pipes. Then one night, my wife brought home a new microwave. Just by a stroke of luck, part of the packaging was a piece of molded cardboard that had a 45-degree bevel running down one edge. It looked like it would work perfectly, so I laid some shiny plastic tape over it and made a mold. Here you can see the pieces that I made from that mold. The right side is just a flat piece. I did quite a bit of research on this, and found many pictures and drawings of both sides. I finally concluded that only the left side had the heat shield to keep the hot exhaust from going into the supercharger intake. I put the flat piece on the right side to simulate the opening from which the exhaust pipes exit.
First came a few coats of scratch filler primer with wetsanding in between. I chose this scheme out of a book called Messerschmitt Me-109: From 1942 to1945
I sprayed the bottom with RLM 76. I also sprayed the sides of the fuselage and vertical with this color.
Before I did any masking, I sprayed the area of the rudder and spinner white and the area of the unit band red. Then I masked the rudder and the unit band. I also masked the spiral stripe on the spinner and then sprayed the rest of the spinner black. Finally, I masked around the whole spinner and sprayed the camouflage. The colors used on the top of the plane are RLM 74 and RLM 75. After I finished the camouflage, I masked the canopy and sprayed it with Ford and GM Engine Blue. I also mixed a small amount of this color with some Gloss White to make a slightly lighter shade and used that to add some highlights on the windows. With that, the basic scheme was done.
For a little weathering, I mixed up some Rust and Flat Black to make a dark, sooty brown. I used this color for the streaks in front of the guns and behind the exhaust pipes. I also sprayed it on all forward facing surfaces such as the front of the gun blisters and the front of all the little scoops.
The canopy frame needed some definition, so I also sprayed the sooty brown around the frame. I did not mask the windows because I wanted them to have a dirty look.
As always, the markings were a little tedious. In the past, I have used Frisket film to create the masks, but I have had problems with Frisket film not sticking well to the matte finish of the camouflage colors, so this time I used shelf paper. It sticks better, but will sometimes leave some of the sticky behind.
The rudder needed some detail, so I sketched some lines where the ribs would be and then sprayed some shading over them. I used Flat Gull Grey, but something more grayish and less brown may have worked better for the effect.
Finally, I added some panel lines, and she's done!
The total weight of the plane ended up at around 60oz. This put the wing loading at a modest 23oz per square foot. I flew the plane recently at Point Fermin in San Pedro, CA. On the first flight, it was a little tail heavy, but a couple of ounces of lead fixed that. The second flight went well, but the wind was not booming. On the third flight, the wind was blowing at around 20mph. I only had 8oz of lead so I stuck that onto the bottom of the plane and gave it a toss. It flew much better with a little more weight, but even at 68oz, the wing loading is still only at 27oz per square foot. I will probably load the plane up to around 85 or 90 ounces, which will put the wing loading at around 34oz per square foot. On a good day at Point Fermin, you can fly planes with wing loadings up into the 40's, but at that weight, they start getting tricky to launch.
There was some concern among some of my friends that the vertical would be too small. I wanted to keep it scale and did not enlarge it. My thinking was that the tail moment is long and the fuselage has large flat sides, both of which would help with stability. The plane does wag its tail a little when it is going slow or on the way back down from a stall turn, but it is not a big problem. I find I can minimize this by tapping the ailerons on the way down, and I usually do this anyway.
Overall, I am happy with the way the plane flies. It still is not punching quite as high as I would like in half-pipes, but I think loading it up a little more will fix that. A little more tweaking and it should be good to go.
This has been a great project. It took some time, but I am very happy with the result. I hope you enjoyed this series. Now, let's go hit the slopes!
Thanks Brad! I noticed the clamped.jpg was missing. A few other things got switched around from how I submitted it, so some of the pictures are a little out of synch with the text.
I also noticed that the link to the book that I chose the scheme from is there, but the image of the scheme I chose is not. Here is a link to that image on my site:
And here is the missing clamped.jpg. It just shows how I clamped the mold for the supercharger intake together.
I am new one on this DIY field.
I have built a canopy mold for my F3A plane
but I got problem that is not easy to pop off .
I notice that you sprayed something with PVA
can I know what is the "PVA" and what's something with exactly.
thanks in advance.
Im in the process of creating a mold from a plug at the moment for a 2m slope soarer/ds ship. Ive created my parting borad in the same way as yours however was wondering what the clay was that you used? Is it just normal craft clay that can be brought from craft supplie stores or is it a special kind of clay??
Also after you seal the gap between the plug and the parting board, do you attempt to wax the clay or just spay it with pvc when you spray the entire side of the plug and parting board??
Thanks, your help is much appreciated.
The stuff I use is just called modeling clay. I get it at South Bay Plastics in Torrance, CA, but they don't have a website. I did a search on the web and there seems to be lots of different varieties available. I think just about anything would work - maybe even Playdoh.
The clay is fairly soft, so you wouldn't want to try to rub wax on it. Just PVA over it.
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