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EL-39 - Semi scale RC jet for 120 mm EDF

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Creation's quality: 5.0/5 (19 votes)
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3D model description

EDIT -22.07.2021:

Added a new EDF housing that can use the HET motor without any heatsink because the heat sink can be hard to find now. EDF-housing04-Noheatsink.stl

It supports the motor all the way through and has a gap for air to pass around the motor. It should be printed from a more heat resistant material than PLA, and that goes for the impeller as well because the lack of an extra heatsink can raise the motor and axle temperature to where the PLA will start to soften.


EDIT:

Added a new canopy that is one main piece instead of two for printing in a very large printer (in addition to the front windshield part). The new files are Canopy01-onepiece and canopy02-onepiece.

The human is not included.


Specifications:
Length: 1858,5 mm
Wingspan: 1451 mm
All up weight: 7,2 kg (prototype #1), 8 kg (prototype #2), 7,5 kg (prototype #3)
CG: 83-103 mm from the leading edge at the wing joint with the gear in the up position. There is a protrusion on the top of each wing surface to indicate the safe 83mm/25% MAC position. Gear up or down should make little difference because of the low weight of the nose gear. The prototype maidened with CG at approximately 90 mm. 103 mm CG has been tested and flies very well.


Initial control throws:
Elevator: Up 18 mm / Down 16 mm
Ailerons: Up 20 mm / Down 15 mm
Rudder: 15mm / 15 mm

Use 30% exponential on all surfaces to reduce center sensitivity.

Appropriate pilot figure:
https://www.thingiverse.com/thing:2970724


Video of the prototype without flaps:
https://youtu.be/znbaBhUY25k

Maiden videos:
https://www.youtube.com/watch?v=9tShEHO5M5s
https://www.youtube.com/watch?v=Gp0sF1WKZ7w

High speed fly bys and landings compilation:
https://youtu.be/KzPiHn8WywE

Onboard videos:
https://www.youtube.com/watch?v=uDD7gKV2YSY
https://www.youtube.com/watch?v=_93jys9oADY

Various flight videos:
https://www.youtube.com/watch?v=VcE9QgbNThE
https://www.youtube.com/watch?v=jZJCof5v06M
https://www.youtube.com/watch?v=DpYUfhk2Kec
https://www.youtube.com/watch?v=E4S3TekVd6I
https://www.youtube.com/watch?v=JWw4-YrTFSI
https://www.youtube.com/watch?v=fBd4eTZwPW4
https://www.youtube.com/watch?v=LnProCnHUOs
https://www.youtube.com/watch?v=1EPln7NoYhA
https://www.youtube.com/watch?v=67ruv_F0Jjk


Build notes and BOM is moved to the text file BuildNotes.txt because of new limitations on Cults when i updated the page 17.11.2020.

3D printing settings

Most parts should be printed with one 0,4 mm perimeter only and no infill off course. The exceptions are hinge pieces, small parts and landing gear parts which should be printed with many walls or solid infill.

EDF-housing should be printedwith 100% infill and with three perimeters.

EDF-impeller should be printed with 6-8 top and bottom layers and 6-8 perimeters and 0% infill.

Fuselage-parts need 3 bottom layers and six top layers for the most part.

I recommend that Nose03 be printed with two perimeters for the first 120 mm so that the gear mounts are strengthened.

Fanrail01 need to be printed solid if you plan to drill them for an aftermarket EDF.

Maingearmounts01 should be printed with six perimeters and twenty top layers to give something for the retract mounting screws to grab on to. Bottom layers can be just four or five. Infill isn't important. Iuse zero infill.

Maingear01-02 should be eight 0,4 mm perimeters, twelve top and bottom layers and at least 50% infill. The same goes for the nose gear parts.

  • 3D file format: STL, TXT, and ZIP
  • Last update: 2021/07/22 at 16:08
  • Publication date: 2018/06/14 at 23:34

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Norwegian inventor/designer/cat owner.

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211 comments

Buy 1 time per 1 print, right?

You can print how many you want. You get the files to use over and over if you need to.

Hi, I bought the L39 Files and the Design looks great! I would like instead to print all parts, printing negative Molds of the fuselage but i'm unfortunately not skilled enough with fusion 360 to join the parts together to get one large piece, may you provide me the fuselage as one piece?
Please let me know what it will cost and thank you for your feedback
Best Regards
Zoran
zo.jevtic@gmail.com

Hi.
Sorry, but I don't have a single part fuselage in CAD. I designed it in multiple parts. I don't have time now to make it a solid single piece as it was made for printing from the ground up.

Too bad, this one won't fit on my printer after buying it!!

I've printed this on a Prusa MK2S. I split some of the parts into 2 pieces to fit on the build plate.

I have no plans for a smaller version. If anything I will make a bigger version.

Will you make an 80mm or 90mm version??

Will you make an 80mm or 90mm version??

If you want just the frames you need to print the regular canopy parts and cut the glass out. That's what I did to the one I did with separate glass.

Love the files, thanks for sharing! I'm working on printing it myself, the airframe is done and just working on the small bits now. One question on the canopy pieces, there's the complete pieces and the plugs, but is there a way to print just canopy frame to put clear vacu-formed parts in? Now sure what your CAD model of the solid canopy parts is like, but if it's easy to just remove that inset piece. If so, that would be awesome. Thanks!

Uhhhh, awesome plane, congratulations!!!! Wish I could make 3d desing as you do!!!

Hello, one more question, this time regarding the retracts. I bought those from hobby-china via the link in the build notes (JP Hobby Alloy Electric Retracts). Again, the dimensions seem to be off a little. Here is a photo of what I mean. I cannot fit it more in: https://snipboard.io/UlguS7.jpg
Also, in the main gear bay area, I cannot fit the retract cover as shown here: https://snipboard.io/ahCXG4.jpg, here: https://snipboard.io/CMnYOf.jpg and here: https://snipboard.io/hdbwCz.jpg The cover itself fits into the wing space but the retract seems to be too wide.
If I can ask, what are the supposed dimensions for the retracts? Also, may I ask what exactly is the nose/nose gear assembly supposed to be like (inside)?

Thanks again...

Hello, one more question, this time regarding the retracts. I bought those from hobby-china via the link in the build notes (JP Hobby Alloy Electric Retracts). Again, the dimensions seem to be off a little. Here is a photo of what I mean. I cannot fit it more in: https://snipboard.io/UlguS7.jpg
Also, in the main gear bay area, I cannot fit the retract cover as shown here: https://snipboard.io/ahCXG4.jpg, here: https://snipboard.io/CMnYOf.jpg and here: https://snipboard.io/hdbwCz.jpg The cover itself fits into the wing space but the retract seems to be too wide.
If I can ask, what are the supposed dimensions for the retracts? Also, may I ask what exactly is the nose/nose gear assembly supposed to be like (inside)?

Thanks again...

Here is a photo of the heatsink itself: https://snipboard.io/PXDWm7.jpg
And here: https://snipboard.io/ZhNtMn.jpg I attempt to fit it in, but I get this far, and then the friction/resistance is too high and I cannot push it more in with my hands. I suppose I could use some tools to get more force but I don't want to damage the motor, heatsink, or the housing.
I purchased specifically this heatsink: "Heat Sink 75mm for 50mm Motor and Ejets Jetfan 120 EDF" from turbines-rc.com as recommended in the build notes.

Can you post a picture of the heatsink to the RCGroups thread, imgur or another image hosting site?

Thread: https://www.rcgroups.com/forums/showthread.php?3054055-3D-printed-120mm-EDF-3D-printed-1-6-5-scale-L-39

The inside diameter is 54,4 mm by design, which usually ends up around 54 mm after printing. The heatsink should be 54 mm. Dimensions from a store that sells them: https://fanjetsusa.com/product/e-jets-jetfan-50mm-heat-sink/?v=4096ee8eef7d

Hello, I have a question regarding the EDF-housing. The motor with the heatsink installed does not fit it. I mean it barely starts going inside, but when I get it halfway in, I cannot push it more. When I measure the outer diameter of the motor with the heatsink attached, it is 55mm. And if I measure the diameter of where the motor should go in the STL file, it roughly equals 54mm. When printed and measured IRL the diameter is the same.

Yes. The inner panels stay attached to the fuselage and the outer panels are removeable. The flaps stay attached to the outer panels. This is done so that the plane will stand on the wheels without the wings attached.

are the wings detachable?

They don't need to open 90°, but if you can't get them to open far enough either move the bracket on the door slightly closer to the hinge point or extend the arm with a piece of plastic or fiberglass.

Different servos have different range.

Does anyone have a suggestion for FPV hardware that could be used/you use with this plane?

Whatever works when printing TPU. TPU printing is very individual to the printers. I have used many different variations of settings. 10% infill, one perimeter and 0,2 mm layers works fine. Two perimeters also works and gives stiffer tire. You'll probably need 4 bottom and 9 top layers for it to cap off the top and bottom with similar stiffness.

Whatever works when printing TPU. TPU printing is very individual to the printers. I have used many different variations of settings. 10% infill, one perimeter and 0,2 mm layers works fine. Two perimeters also works and gives stiffer tire. You'll probably need 4 bottom and 9 top layers for it to cap off the top and bottom with similar stiffness.

Hi, what settings should be used for printing the flexible parts (using TPU)? Mostly how much infill and shell thickness (perimeter count), bottom/top layer counts? Thanks...

Just a suggestion about the print times. I shortened the print times almost by half by printing with a 0,6mm nozzle at 0.37 height at a speed of 75. This creates a very strong print for the fuselage. Printing on a Anet A8 plus. I might go lighter on the wings, still testing.

I use Simplify 3D.

Have you tried printing? It might be fine in real life and only a preview artifact.Try turning off "Compensate Wall Overlaps" also un der the Shell. I don't use Cura but tried slicing now in Cura and it's fine.

Which slicing software would you suggest? I used Creality slicer for the most parts and it came well. I noticed the problem with the wings so I wanted to try Cura but it is the same.

I don't use Cura myself. Try the forum on RCGroups where. Something is wrong if there are holes with 0,4 mm extrusion. It's not a problem with the model. The material thickness there is 0,7 mm.

Each of the large parts of this plane can take two to three days to finish.

The problem still persists even with 0.2mm layer height. (print time over a day)
snipboard.io/Idunor.jpg

Why on earth would you use 0,4 mm layer height? Max 0,2 mm layer height.

If I use 0.4mm nozzle and print layer height 0.4mm and 1 wall line of 0.4mm, it is very similar: snipboard.io/N1FqxA.jpg
The print time is almost 17h with a print speed of 55mm/s (wall speed of 27.5mm/s and travel speed 150mm/s)

I use Print With Smile PLA now. It's very good. Just about any PLA will be good.

It's because you're extruding too wide. Don't extrude wider than 0,4 mm.

Do you guys know how to get rid of this problem (link below) when slicing? The surface is not seamless. I imported the STL file to Cura but it has these weird empty spaces. Here is the screenshot. I didn't notice this problem when printing nose/fuselage.

screenshot: snipboard.io/odfWz8.jpg

Do you guys know how to get rid of this problem (link below) when slicing? The surface is not seamless. I imported the STL file to Cura but it has these weird empty spaces. Here is the screenshot. I didn't notice this problem when printing nose/fuselage.
https://snipboard.io/LeUt9j.jpg

Which filament do you recommend?

2,5 mm or 3 mm self tapping is good. I use hex servo screws. Using just two screws is fine.

Hello, what screws should be used to screw fan intake to the fuselage-04? Also, I see there are three holes on the fan intake but only two on the fuselage-04? Should only two screws be used?

In simplify3D go to the Advanced tab in the print settings and select "Merge all outlines into a single model". This removes all internal structure and makes themempty solids. Use three or four perimeters to achieve 2 mm wall thickness.

hello.. would it be possible to give a solid file 0r stl file of the of the outer skin (2mm thick) only as we would like to make a mold for this model as the internal structures would be useless for us in the mold making process?

Rods are solid and tubes are hollow. You can off course use 4 mm tubes for the short joiner pieces. Try to figure out what the rods and tubes are there for any you will understand why they are as they are. Tubes are large diameter and hollow to save weight, or slide into each other, so outer and inner dimensions have to coincide.

And the 4x16 mm carbon rod? What should be the inner diameter? Should it be hollow or solid? (5mmx660 and 5mmx344 rods also)

yes (For all your questions)

Hello, where and what kind of rods should I order? I am a little confused by the dimensions. Everywhere I search I find: [External diameter]x[Internal diameter]x[Length]. Does 4x16 mm for fuselage mean 4mm external diameter and 16mm is the length? What is the internal diameter? And 9x11x576mm? Is external and internal diameter swapped? The same with the 11x13x576 carbon tubes.
Thanks for any help.

Glue in some wood blocks and you're set.

Hi, I was wondering how the flap servo is held ? Is it hot-glued ? There is a photo but I can't deduce from that.

Danke 🙏

Wo komme ich denn die cfk Bzw Carbon Rohre für die Tragflächen her ich finde im Netz keine 11x9 bzw 9x7 wer kann helfen? Wo bestellt man das?

I tryied the Nosegear04-Shockcap, but it broke when I screwed id, it was a little brittle. So, I decided to try to reduce the diameter of the metal shock cap with a drill press and a wood file as a poor man's lathe and it worked ! It was so satisfying when the shock fitted into Nosegear03 ! I think other people could like this trick...

Yes they changed it now I think. I haven't had that problem before.

Yes, it's there, thanks. It's too bad for the instructions to be in a .txt now.

Check if the new part is up for you now.

And the opening in Nosegear03 is 15 mm so it should fit after cleaning up the parts.IT should not be a loose fit. I will upload a 14,6 mm versio nfor you once an iccue with Cults is resolved. I am unable to edit the page now.

I measured both STL and Nosegear04 is 14.6mm and Nosegear04-Shockcap is 14.8mm diameter. If you can see the problem on your computer, can you re upload it please ?

Nosegear04-Shockcap is there to replace the too large aluminium shock cap. It's smaller than Nosegear03 by design, so it should fit in the hole with clean prints. Try cleaning up the hole in Nosegear03 with a file or sandpaper roll, or sand the outer surface of Nosegear04-shockcapulntil it will fit. If you open both parts in your slicer and move them over each other you will see that it fits.

Hi, what is the Nosegear04-shockcap for ? Because it's diameter is slightly bigger and doesn't fit into Nosegear03. Also, my shock caps are also a little bigger than Nosegear03, what can I do ? Here is the shock I bought: https://www.ebay.ca/itm/292727268666