DIY 50mm EDF RC Aero L-39 V2

by grifflyer | January 1, 2020 | (11) Posted in Projects

Some of you may have seen the L-39 that I released a couple years ago. My main goals with that design were to make it a relatively simple build while still having it resemble the L-39, as well as giving the builder the ability to fly it with a 50mm EDF, or an equivalent to the FT F pack. After flying it for a year or so I started to notice how boxy everything was, and I found lots of little spots where I could make the design a little easier to build and more importantly, look quite a lot better.
For version two, my goal was simply to retain or improve the awesome flight characteristics of the original design, while getting the model to look more like the full size L-39. This is the end result!

Free Plans: Download Here

The biggest changes I've made are adding many more facets, and changing up the geometry of the intakes as well as other curves. Aside from a slightly bigger horizontal stabilizer the plane has the same wing and vertical stabilizer located in the same spot on the airframe so the flight characteristics of the original model are carried over into version two. The EDF power system has not changed so if you've built V1 as an EDF you can build version two, sadly the option to build the jet with a FT F pack equivalent is no longer available, although retrofitting one wouldn't be too difficult.

Top speed is great and slows down very well for landing. I was able to clock V1 doing 64 mph at Flite Fest and V2 definitely feels a tad faster, so I'll say it is the realm of around the 70 mph.
The L-39 tracks like an arrow and the controls are very smooth giving you the ability to fly like a pattern ship, but it can become "snappy" and abrupt when you really start banging the sticks around.
If your plane stalls it will likely drop a wing but it is nowhere near entering a spin, all you have to do is level the wings and then power out.
Since the plane lacks a rudder the aerobatic ability is limited to the basics such as, Loops, Rolls, Inverted, Split S's etc.
Take offs-
I like launching this plane by holding it right in front of the wing and giving it a really strong toss, you really need to give this bird a solid toss or else it won't have enough airspeed to sustain flight.
Landing this model is quite simple all you need to do is bleed almost all your airspeed and get it close enough to good 'ol terra firma to put ground effect to work, then right before to hid land, flare the plane and you'll "ride" a cushion of air to the ground.
Skill level-
I'd want to wait until I've flown at least one unforgiving plane that flies quite fast and taught you how to avoid stalling.


Test Fly RC on January 6, 2020
Good job! I hope to build this jet some time this year!
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mach1 rc on January 6, 2020
Great plane!!! I love jets
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Jackson T on January 7, 2020
That is one sweet looking plane!
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CrazyFastFlying on January 7, 2020
Awesome jet Grifflyer! I am definitely going to try to build one this year!
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CarolineTyler on January 7, 2020
Ok!! i'm sold - It looks super with it's new facets. I've downloaded and printed the plans, have the foam and just need to sort out a 50mm EDF (that FMS one for £20 and some change looks perfect). Any more pictures of the build process to help out with putting this model together - EDF location etc?
Thanks in advance, Caroline
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grifflyer on January 7, 2020
I didn't get any pictures of the build process for V2, everything is labeled in the plans so fitting everything together shouldn't be too difficult. You can look through the instructions for V1 They will give you a pretty good idea of how everything fits together. If you have any questions please don't hesitate to ask.
Good luck with your build!
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CarolineTyler on January 7, 2020
Great stuff! Thank you :)
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GremlinRC on January 7, 2020
That looks fantastic. Well done, definitely on my build list.
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elijahf111 on January 9, 2020
is there/ will there be tiled plans available?
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grifflyer on January 9, 2020
No not this time, but you can still print them with a regular household printer if you use Adobe Reader. All you have to do is open up the plans in Adobe Reader and select print. After the print window opens up there should be a section in the middle of the window labeled "Page Sizing & Handling" right below that there should be options to choose between "Size" "Poster" "Multiple" and "Booklet" You are going to want to select the "Poster" option. Next, ensure your tile scale is set to 100%, your overlap is set at 0.005 in. and that you have the "Tile only large pages" option selected. You can also select "Cut marks" which will make taping the sheets of paper together easier, but it will increase your page count from 8 to 12. Lastly, go down to the bottom of the print window and click print.
Note: If you do not have the poster option on your laptop you may need to upgrade to the latest version of Adobe Reader. It may even be old enough that looking in the program options for updates does not work. You will have to go to Adobe website to get new version.
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MiniacRC on January 16, 2020
Shucks that thing looks GORGEOUS! I remember putting your old L39 on my bucket list but this guy is an amazing replacement. Gotta figure out a way to fit props on it now!
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CarolineTyler on January 31, 2020
50mm EDF ordered, plans printed....looking forward to this!!!
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delli1221 on March 28, 2020
This looks awesome, great design! Any idea how the FMS 50mm 5400kv 3s motor would perform? Do you know how much thrust your 4s setup gives you?
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grifflyer on March 29, 2020
I don't really know how well it will perform, my 4s setup puts out about 800 grams of thrust, if you removed the internal paper and built light you might get it to work. If you don't want to take chances my Grunjet can fly off of the EDF you have.
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RodgeyD on April 3, 2020

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RodgeyD on April 3, 2020

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Llamaman197 on August 20, 2020
Hey so is there any instruction on how to put it together?
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grifflyer on August 21, 2020
Unfortunately there isn't, however you can look through the instructions for version 1. That will give you a pretty good idea of how V2 goes together
If you have any other questions feel free to let me know.
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DIY 50mm EDF RC Aero L-39 V2