Micro Mirage III

telnar1236

Elite member
I decided to take a bit of break from building my F-104 today and throw together a little Mirage III out of foam board using some electronics I had sitting around. The plane runs on a 40mm AEORC fan which outputs 240g of thrust to give the plane a TWR of 1.25 with a 1000 mAh 2s battery. It's a simple park-flyer, so there is no rudder and the elevons are run on lightweight 7g servos. The pink color is a lightweight filler material that really smooths out the contours and makes the surface less rough (it's drying in the photos and needs some sanding). It's not too scale, but I'm happy with how it turned out and it's a relief to do an easy 3-hour build after working on a complex balsa design for two months. If it flies well, I'll probably post some plans since I don't see too many sub-250g EDFs with decent performance and I pretty much had to make plans to build it in the first place. The build is similar in style to Steve Shumate's park jets, and the entire airframe with electronics can be built for about $40.
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Kam5691

New member
I decided to take a bit of break from building my F-104 today and throw together a little Mirage III out of foam board using some electronics I had sitting around. The plane runs on a 40mm AEORC fan which outputs 240g of thrust to give the plane a TWR of 1.25 with a 1000 mAh 2s battery. It's a simple park-flyer, so there is no rudder and the elevons are run on lightweight 7g servos. The pink color is a lightweight filler material that really smooths out the contours and makes the surface less rough (it's drying in the photos and needs some sanding). It's not too scale, but I'm happy with how it turned out and it's a relief to do an easy 3-hour build after working on a complex balsa design for two months. If it flies well, I'll probably post some plans since I don't see too many sub-250g EDFs with decent performance and I pretty much had to make plans to build it in the first place. The build is similar in style to Steve Shumate's park jets, and the entire airframe with electronics can be built for about $40.
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It looks really nice! One question, where do you find that light pink-looking filler? I was thinking of making one of these and I needed something to smoothen out the overall shape of the fuselage. Thanks!
 

telnar1236

Elite member
It looks really nice! One question, where do you find that light pink-looking filler? I was thinking of making one of these and I needed something to smoothen out the overall shape of the fuselage. Thanks!
It's Minwax color changing wood filler. If I remember right, I got it at Lowes, but I expect you could find it at most hardware stores. I mostly use it with balsa, but it seems to work fine with foam too. The color does change as it dries, as stated in the name, so the final result is tan, which I find preferable for painting.
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dap35

Elite member
It's Minwax color changing wood filler. If I remember right, I got it at Lowes, but I expect you could find it at most hardware stores. I mostly use it with balsa, but it seems to work fine with foam too. The color does change as it dries, as stated in the name, so the final result is tan, which I find preferable for painting. View attachment 195057 View attachment 195058
Looks really good! How much weight does the filler add?
 

telnar1236

Elite member
Looks really good! How much weight does the filler add?
I know this isn't that useful of an answer but it's very dependent on how much filler you add. The density is a bit higher than balsa, but it's still pretty light. That said, carelessness when shaping the plane can lead to a significant increase in weight, and the weight of the filler does need to be factored into the original design. It's also very important to sand the filler as thin as possible. In the Mirage III, the filler accounted for about 20 g of the 190 AUW. As the airplane gets larger, this fraction decreases if everything is done right. For example, in the 1 kg F-104 I am currently building, I expect the filler to only account for about 30-40 g.
 

dap35

Elite member
Thanks. That helps I'm looking for an alternative to the light weight spackle that I have used. Its OK, but it doesn't sand well.
 

telnar1236

Elite member
Thanks. That helps I'm looking for an alternative to the light weight spackle that I have used. Its OK, but it doesn't sand well.
Glad it helped. This is both lighter and easier to sand than the lightweight spackle I used in a hotwire model a while back.