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Scratch built 70mm EDF fighter jet

#1
I was inspired to attempt to create my own designs after finishing up an FT Viggen.
This is a model designed by me although I must admit it turned out very similar to an F-16 style aircraft.
I model the aircraft using blender in 3D and then utilize UV mapping and some plugins to "unfold" the 3D model into 2D blueprints.

3D model and corresponding 2D format

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small scale model for proof of concept (work out any issues folding)

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Large scale plans scaled and printed on several sheets of standard printer paper

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70mm EDF power pod and ESC

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First version constructed from Elmers foam board (extremely heavy and under powered)

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Minor mishap with the center of gravity

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Rebuilt using Adams Rediboard (dollar tree board) Made some modifications to wing design and tail section. I cannot believe how much lighter the air-frame is with this foam board.

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Its pouring rain today so whenever I get a chance to maiden her I will upload some images or videos of the flight

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While I wait to maiden I will be working on my next design the SU47

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Thanks everyone and any comments or recommendations are welcome!
 

DamoRC

Well-known member
Mentor
#2
Nice! I like how pointy it is and well done on the build.

One suggestion is to make the nose two-piece, a short piece at the front that you can cut off and replace if you have any more "mishaps"

What was the all up weight of the original heavier model and the current model and what battery did you use?

DamoRC
 
#3
Weight

The weight of the original wing (Ghostline foam board + Elmers foam board) was 1.16 lbs

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The weight of the fuselage + tail section (disassembled in the photo but the weight should remain the same) was 1.46 lbs

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So that is a total of 2.62 lbs and that is just the foam with no electronics, battery, or servos :eek::eek:

The EDF unit I have pushes 2.3 lbs thrust running a 14.8 lipo
So when adding in the servos (40g), battery (350g) and the EDF (130g) its clear that I was a long shot from a 1:1 thrust to weight.

Now with the Dollar Tree foam board the weight of the entire plane with servos and ESC (sorry they were glued on) was only 1.17lbs!!!

20170828_151041.jpg

with the EDF and a 3300 mah 14.8 lipo im looking at right around (480g) or 1.05 lbs or (330g) or 0.72 lbs (with the smaller 1800 mah lipo)

Grand total should be 2.22 lbs 3300 mah lipo
Grand total should be 1.89 lbs 1800 mah lipo

1.03:1 Thrust to weight 3300 lipo
1.21:1 Thrust to weight 1800 lipo

I might just be able to keep this thing in the air this time!!!

I will definitely take the sectioned nose into consideration. It appears the foremost few inches take the majority of the impact so it would make sense to have that bit removable.

Thank you for the suggestion and compliments!
 
#4
Weight of foam board

Just a little FYI here are a few samples of various foam board I currently have and their weights respectively.

samples are 2in x 2in with the measurement of weight in grams

Walmart Ghost line black foam
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Elmers foam
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Dollar Tree ( Adams Readi-board)
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Flite Test brown water resistant foam
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As you can see the Elmers and Ghostline are fairly heavy compared to the cheaper alternatives Dollar Tree and Flite Test

Hope this may save someone else the same mistake I made!!!
 

Namactual

Well-known member
#5
That is pretty cool, and it looks like the SU is coming along nicely as well.

I tried using blender on a few occasions and I just could not get past the user interface. It's so backwards from every other suite out there. It is very powerful though. The best 3D suite for the price, that's for sure! :p

Keep up the good work!