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

3D model description

The human is not included.

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:

Video of the prototype without flaps:

Maiden videos:

High speed fly bys and landings compilation:

Onboard videos:

Various flight videos:

Safety warnings:
-The EDF is a very highly loaded assembly at high speed so it's important that you know what you are doing.
-Make sure the integrity of the printed impeller is good before trying to run it.
-Always wear protective glasses when test runnin the fan. Always protect your eyes.
-Do NOT run the fan at high power while holding in your hand.
-Keep your hands and any loose items away from the fan when running. It WILL shred your fingers if they get sucked in, and the suction force is very strong. If something gets sucked in it can damage the impeller and potentially shatter, throwing loose debris out.

Build notes. Most of the plane assembly is pretty self explanatary when you have the parts in front of you, but here are some explanations. Read carefully:

300x300 mm print area is required for the largest parts. Many parts fit on a 200x200 bed, and some even smaller printers. I use a JGAurora A5 with TMC2100 stepper drivers for the big parts and a Wanhao Duplicator i3 for the smaller parts.

Good quality PLA should be used for the entire model. I recommend PrimaValue PLA:
Main tires, nose tire, fanrubber and fanseals need to be printed from TPU or other rubber like filaments.

I recommend adding drum brakes. They only add ~14 g to the total weight of the plane and work extremely well. I have uploaded custom drum brakes for the plane in a different free listing:

Fuselage 01-07 should be glued together with CA and indexed with four 4x16 mm carbon rod pieces between each joint. I use thick CA and apply kicker to the edge after joining. The fuselage sections can be lightened by removing the bulk of the mating faces of each part. The example below shows the same part lightened and not lightened. It saved 30 g on this part alone, which adds up to a lot of weight on the finished plane. Make sure you leave a decent edge for glue to stick to when mating the parts, and make sure the different openings on the face are connected by solid material when you lighten them:

Fuselage02 and Fuselage03 have small hinge lines for the main gear doors. These should be drilled or checked with wire before they are glued together because it's hard to do after assembly. If you didn't check them in advance and they are tight, you can use a 1 mm piano wire in a drill and use it as a flexible drill bit to open them up.

Nose03-Nose05 should also be glued together with CA and 4x16 mm carbon rods like the fuselage pieces. Nose01 and Nose02 should be installed with M3 screws. These two need to be replaceable to aid with access to the nose components and for replacement in case of damage.

Wing01, or Wing01-flap if you want flaps, must be glued to the fuselage with the 9x11x576 and 11x13x576 carbon tubes. The outer wing panels slot into these carbon tubes.This is done so that the plane can stand on the wheels during service, storage and transport. Wing02 and 03 were updated with better internal structure on 07.04.2020.

Horizontal stabilizers should be joined and connected with the fuselage with 5mmx660 mm and 5mmx344 carbon rods or tubes. Glue the tubes in the stabilizer on one side and use screws on the other stabilizer to hold it all together. That way they can be removed to access to the servos.

All control surfaces use 3mm carbon rods and 3x6x2,5 mm ball bearings as hinges. Use two 3 mm split lock washers between the control surface and bearings to center each control surface, as shown in one illustration photo. Position them in slots that keep the control surface centered. The bottom of some control surfaces have tiny holes to indicate which side is the bottom, and to allow glue to be applied to the hinge rod through them.

The shock absorbers need to be modified with the 3D printed pistons Shockpiston02 and 10000CST differential oil in order to dampen the heavy airplane on landing impact. The springs can be stretched slightly to increase tension.They should be very heavy to compress. Shockpiston01 can be used with thicker oil than 10000CST or for tuning if lighter damping is needed. One should also install an O-ring or rubber grommet on the exposed shaft between the housing and bottom cup to work as a soft end stop. The main gear will most likely bottom out when sitting on the ground, but will stretch on take off and be ready to absorb the landing shock when you land. Airplane shock absorbers are not designed to give a good ride quality, but to absorb the huge impact of the landing.

Glue the 11x51 mm carbon tubes into Maingear02 and then attach the exposed end of the carbon tube in the retract units. To install Maingear01 to Maingear02 use two 3x6x2,5 mm ball bearings and two M3x10 mm screws:

Assemble the nose gear as shown in the illustration:

The main gear and nose gear carbon tubes (10, 11 or 12 mm) might need to be doubled up with a second internal tube to increase the wall thickness where they enter the retract units. The strength of these tubes will vary from manufacturer to manufacturer and some need to be doubled to be strong enough for very hard landings. None of mine have required this, but one has broken for one builder.

The ESC should ideally sit inside the compartment over the intake duct, with wires going forward to the receiver and battery. This ensures adequate cooling. Extra capacitors need to be installed in such a way that they fit in the cable tube inside the fuselage.

If the 3D printable fan is used, the recommended HET motor should also be used with the heatsink. The motor shaft should have a hole drilled half way through it for one of the M3-16 mm impeller grub screws, because heat soak from the motor can cause the impeller to come slightly loose if just a flat spot is used. The prototype fan pulls 83 A at full throttle on a fresh 12S charge when installed in the plane. I recommend that the PLA impeller is not used for extremely hot environments. Hotter materials may work but that's more experimental than using PLA, and there are other properties that come into play, like elasticity.

Here's how you open up the hinges for the wheel doors. Use the same piano wire you use as the hinge pins to open up the holes with a drill. Cut the end of the wire to make a flat spade shape before drilling for easier drilling:

Droptank01 is one tank. The alignment holes are designed for 1,75 mm filament and are offset so that the parts only go together one way. Droptank02 is the mounting brackets between the tanks and the wing weapon mounts. The tall one goes in the front and the short one in the back. Glue them to the tank and secure the tank to the wing with M3 screws.

Canopy latch: Make the latch from 50 mm long pieces of 3x5 tubing and 3 mm rod. Use a 4x0,3x20 mm spring and an M3 screw as the handle on top according to the illustration: When using a latch in the rear for the canopy, glue Canopy01 in place on the fuselage, and add a pin to the top of Canopy02 so that it slots into Canopy01 and then is locked in place i the rear by the latch. Add a hole to the rear of Canopy03 for the latch.

Part list. Some links have my affiliate code, which helps me pay for future project development:

3x Shock absorbers:
Springs 1.8x18x35 mm for the main gear:

10000 CST diff oil for the shocks:

M2x16 mm screws for the wheels.
Assorted M3 screws, cap head and countersunk head. 8-mm to 35mm length.
Assorted M3 grub screws.
Coutnersunk M4x38 mm screws for the main wheel axles.
#1 countersunk self tapping screws for the servo hatches.

Adjustable pushrod connectors for wheel doors:

24 3x6x2,5 mm ball bearings for control surface hinges and landing gear hinges:
4 4x8x3 mm ball bearings for the main wheels:
2x 12x18x4 mm ball bearings for nose wheel steering:
7x Nylon clevises for control surfaces:
7x M2 metal pushrods for control surfaces:
7x Snap link clevises for control servos:
1,5 mm piano wire for gear door links and hinges.

1x 5mmx500 mm carbon rod for horizontal stabs (rear rod)
1x 5mmx344 mm carbon rod for horizontal stabs (front rod)
Assorted short lengths of 4 mm carbon or bamboo rod for indexing when joining fuselage parts.

2x 3x225 mm carbon rods for aileron hinges
2x 3x340 mm carbon rods for flap hinges
2x 3x286 mm carbon rods for elevator hinges
1x 3x276 mm carbon rod for rudder hinge

2x 6x8x400 mm carbon wingtip tubes
2x 7x9x440 mm carbon wing tubes
1x 9x11x32 mm carbon tube for nose gear strut
2x 9x11x51 mm carbon tubes for main gear struts
2x 9x11x440 mm carbon wing tubes
1x 9x11x576 mm carbon wing tube
1x 11x13x576 mm carbon wing tube

-12S 5000+mAh lipos. I recommend at least XT90 connectors.
-7x Control surface servos. The prototype flies with these:
Other servos with a case profile of less than 30x15 mm will also fit.
-Optional servo reverser if you are unable to reverse one flap and one gear door servo by other means:
-4x Landing gear door servos and nose gear steering servos: 9-12 g servos with metal gear are recommended. Not SG92R servos as they go crazy when used with the sequencer.
-ESC: 12S 120A+ ESC. I recommend Castle Creations Talon 120 because it has a strong integrated BEC.
The prototype flies with an Aerostar Advance 120A:
-Extra capacitors with low ESR for the ESC because of extended battery wires. At least 660uF total extra capacitance:
-Retract and door sequencer:
-90° outward operating retracts with 11 mm strut clamp are required to use the 3D printable trailing link suspension. I use this (might require some adjustment to operate perfectly):
These are better and don't require a separate sequencer. Pick V2 and outward:
Other retract units will fit. The gear and wheel bays are roomy. The highest quality option is probably the Electron ER-30evo, which should fit with some adaption:
-Motor for the printable EDF:

File name descriptions:

Aileron01 - Ailerons.
Airbrake01 - Fake airbrake shapes for the bottom of the fuselage.
Canopy01 - Front part of the canopy.
Canopy02 - Middle part of the canopy.
Canopy02 - Rear part of the canopy.
Canopylatch01 - Scale non functional outside handle for opening the canopies.
Canopyplug01 - Plug for vacuum forming the front part of the canopy.
Canopyplug02 - Plug for vacuum forming the middle part of the canopy.
Canopyplug03 - Plug for vacuum forming the rear part of the canopy.
Droptank01 - Drop tanks.
Droptank02 - Drop tank mounting brackets.
EDF-housing01 - EDF ousing and motor mount.
EDF-Impeller01 - 11 blade EDF impeller for 8 mm shaft.
EDF-tailcone01 - Tailcone for the back end of a HET 800-motor.
Elevator01 - Inner elevator parts.
Elevator02 - Middle elevator parts.
Elevator03 - Outer elevator parts.
Fanintake01 - Tube to guide air from the fuselage duct towards the EDF housing.
Fanrail01 - Mounting rails for the engine compartment. Pre-made holes for the printable EDF and Changesun 120 mm fan with captive M3 nuts.
Fanrubber01 - Mounting grommets for EDF installation on the fanrails.
Fanseal01 - Flexible seal between the front of the EDF and the rear of Fanintake01.
Fanseal02 - Flexible duct between the rear of the EDF and the exhaust tube of the fuselage.
Flap01 - Innermost flap parts.
Flap02 - Outermost flap parts.
Flap03 - Hinge brackets for the flaps. Fits in Wing02-flap.
Flapfairing01 - Dummy inboard flap fairing for the top of the wing.
Flapfairing02 - Dummy outboard flap fairing for the top of the wing.
Flares01 - Flare discharge openings for the bottom right rear fuselage. Look up photos of the real L-39 to find it.
Fuselage01-07 - Fuselage sections, from forward to rear.
Fuselage01-Latch - Fuselage part with integrated channel for a canopy latch.
Fuselage03-bigESC - Fuselage section with larger ESC channel for bigger than normal ESCs.
Fuselage04-bigESC - Section with larger ESC channel for bigger than normal ESCs.
Headrest01 - Pilot headrest in case of populating the canopy with pilots.
Hstab01 - Inner parts of the horizontal stabilizer.
Hstab01 - Outer parts of the horizontal stabilizer.
Hstab02 - Tips of the horizontal stabilizer.
Intake01 - Intake lips for the air intakes. Separate to simplify painting in a separate color.
L-59-canopy02 - Middle part of L-59 style canopy.
L-59-canopy03 - Rear part of L-59 style canopy.
Maingear01 - The main landing gear trailing link assembly.
Maingear02-10mm - The main landing gear leg for 10 mm carbon tube.
Maingear02-11mm - The main landing gear leg for 11 mm carbon tube (Hobbyking retracts).
Maingear02-12mm - The main landing gear leg for 12 mm carbon tube (JP Hobby retracts).
Maingeardoor01 - Main gear doors to attach to the main landing gear.
Maingeardoor02 - Left inner main gear door.
Maingeardoor03 - Right inner main gear door.
Maingeardoor04 - Horns for the links to close Maingeardoor02 and 03.
Maingearmounts01-Hobbykingretracts - Heavy duty mounting beams for Hobbyking retracts in the inner wing parts.
Maingearmounts02-JPretracts - Heavy duty mounting beams for JP retracts in the inner wing parts. 3mm deeper mounting face.
Maintire01 - Main landing gear tire.
Mainwheel01 - Main landing gear wheel.
Mainwheel01-bb - Main landing gear wheel for 4x8x3 ball bearings.
Motorhatch01 - Hatch for the EDF compartment in the fuselage.
Nose01 - Tip of the nose.
Nose02 - Nose part and nose landing gear compartment.
Nose03-05 - Parts of nose under the cockpit area.
Nosegear01-03 - Nose gear trailing link assembly.
Nosegear04 - Internal part of the nose gear strut.
Nosegear04-shockcap - Some of the cheap chinese shocks have a shock cap that is too wide for the nose gear, and this part makes it all one piece and replaces the top of the shock.
Nosegear05 - Top bearing cap of the nose gear strut.
Nosegear06-10mm - Mounting and steering beam for the nose gear for 10 mm carbon tube.
Nosegear06-11mm - Mounting and steering beam for the nose gear for 11 mm carbon tube (Hobbyking retracts).
Nosegear06-12mm - Mounting and steering beam for the nose gear for 12 mm carbon tube (JP Hobby retracts).
Nosegear07 - Nose gear steering link eye.
Nosegeardoor01 - Nose gear door.
Nosegeardoor02 - Nose gear door hinges with intergrated link hole.
Nosetire01 - Nose landing gear tire.
Nosewheel01 - Nose landing gear wheel without bearings.
Nosewheel01-bb - Nose landing gear wheel for 3x6x2,5 mm ball bearings.
Pitot01 - Pitot tubes for the wings.
Retractcover01 - Covers for the main gear retract bays.
Rudder01 - Bottom part of the rudder.
Rudder02 - Top part of the rudder.
Rudderfence01 - Plate that goes under the top of the vertical stabilizer, over the rudder. Not all L-39 have this. Look up photos of the real L-39 to find it.
Sensors01 - Three rods that fit in the holes under Nose01.
Sensors02 - Antenna thingy on top of the fuselage. Look up photos of the real L-39 to find it.
Sensors03 - Ice accretion transmitter. Goes on the left side of the nose by the landing gear door. Look up photos of the real L-39 to find it.
Servohatchaileron01 - Aileron servo hatches. Install with #0 or #1 screws.
Servohatchrudder01 - Rudder servo hatch. Install with #0 or #1 screws.
Shockeyelet01 - Replacement shock eye end for the shocks to prevent the spring collar from slipping over them.
Shockpiston01 - Two slot shock piston for heavier than 10000 CST oil.
Shockpiston02 - One slot shock piston for 10000 CST oil and lighter weight.
Stand01 - Front stand part. Use a 16 mm Ø x 540 mm long tube or pipe to join them together.
Stand02 - Rear stand part.
Tiptank01 - Rear parts of wing tip tanks.
Tiptank02 - Middle parts of wing tip tanks.
Tiptank03 - Front parts of wing tip tanks.
Tiptank04 - Tip tank front light glass.
Vstab01 - Bottom front part of vertical stabilizer.
Vstab02 - Bottom rear part of vertical stabilizer.
Vstab03 - Middle part of vertical stabilizer.
Vstab04 - Middle part of vertical stabilizer.
Vstab05 - Top part of vertical stabilizer.
Weaponmount01 - Inner weapon mounting points for the wings.
Weaponmount02 - Outer weapon mounting points for the wings.
Wing01 - Inner part of the wings without flap.
Wing01-flap - Inner part of the wings with flap.
Wing02 - Middle part of the wings without flap.
Wing02-flap - Middle part of the wings with flap.
Wing03 - Outer parts of the wings.
Wing03-notank - Outer parts of the wings for wingtips without tip tanks.
Wingtip01 - Plain wingtip without tip tank.
JGAurora - Old Simplify 3D profile for fuselage sections with JGAurora A5 printer.

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 and ZIP



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Norwegian inventor/designer/cat owner.



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I also added 10 mm version of the nose and main gear parts in case you need them.

Thanks friend !
I've found it on yours files ! I gone made a second one ! :)

Maingear02-11mm is for 11 mm trunnions. Do you need 10 mm as well?

Hy plane fly's verry good.
Do you have files for the size opening 10 / 11 mm for retracks of JP ??

Reducing the layer to 0.16 mm eliminated the problem.

I use a layer height 0.2 mm

What layer height are you using when that happens? It slices normally in Simplify 3D for me at 0,12, 0,16, 0,2 and 0,24 mm

The new Canopy02 has another problem, from layer number 934, two peripheral layers will gradually appear instead of one. I don't know if this is a Simplify or .stl file problem.

Thanks for letting me know. I reuploaded a fixed Canopy02 now. You can redownload from your account.

Please check the Canopy02.stl file. It seems to be damaged. After slicing in Simplify3d, there are errors in it. Canopy01 and Canopy03 are OK with the same settings. I downloaded the file again for sure, the mistake is still there.

I order mine on Ebay or Amazon. Hobby King has almost all of them, if you can get a shipment from them.

It becomes a lot cheaper if you try to get the ones you need from a single seller. The shipping stacks up and becomes expensive.

Ebay sellers have often been the cheapest for me. Many sellers will create custom listings if you ask for 600 mm tubes for example.

This is reasonably priced. The seller has other dimensions too, in 500 mm, so he might be able to sell 576 mm or 600 mm long as well:

I know the tubes for this plane can be expensive so I'm trying to avoid these sizes in my other planes.

I was able to find them om Ebay, but quite expensive. Bur ordered now..

Regarding carbon tubes. Some of them are ok to get from elefun, but some tubes are hard to get and really expencive...
Any tips where to get them without paying a fortune?

I will start the build this weekend, and have got the standard rods so I can start building the fuselage.
All the other hardware (ball bearings, clevis...) are purchased.

Today I made the first flight with this model. It flies very well, I'm satisfied. Thank you, good job.

Go to your account, then click "Orders" and then click "View" next to the line with EL-39 and you come to a download page where you can redownload.

Yes I also was wondering if I could download the new improved wings without having to purchase the full file again but I do not see how it is possible

Jeg ser du har endret wing02 og Wing03. Må jeg kjøpe på ny, eller kan jeg laste ned endringene fra Cults?

To get decent clarity print with high temperature and high layer height (0,24 mm leyers works well). Then coat both sides with two or more layers of clear spray paint.

Hello, I wanted to know what product you used to clarify the canopy

Hi, yes you are right, I had skirt setup. I did not know that this had any influence before slicing. After removing this it fits fine. Thanks for the tip.I have not started on the wings yet. I am almost finished with the fuselage. I did the fuselage and nose parts with a 0.6mm extruder then extensive sanding and removing the matting. I also used Esun PLA+. The results of the 0.6mm and PLA+ is very strong but I will be doing the wings and stabs with 0.4mm to minimize the weight. The 0.6mm printed at 0.37 height is very fast as well. One more question, what is your opinion on replacing the carbon fiber tubes with aluminum tubing?

Wing01 model dimensions are 293,35x296,32x179,53, so there should be plenty of extra room on a 300x300 bed. If you have a brin or additional stuff added turn it off.

Hi, I am truly impressed by your design and build. I am very excited to do this project and now with lockdown I have a lot of time on my hands. I have come across a problem with printing the first wing part. It does not fit. I have tried everything. I bought a 300x300x350mm printer because you recommended it but now the file will not fit. As the file is now for wing01 with flaps, I would need a bed of 400x400mm to get to work in Cura. If I separate the two wing parts and then remove a piece of the wing I could get it to work but I have no other solution, am I missing something?

If that's not the problem then maybe you can add a shim under the outer mounting points of the retract unit to angle the retract slightly.

hello i have printed the
drum brakes on the LE-39, now do not close the gates as they hit the servo

hello i have printed the
drum brakes on the LE-39, now do not close the gates as they hit the servo

I bought and downloaded this jet of yours several months ago, but came around to start printing it just a couple a weeks ago.

I have printed ten different 3DPrintLab planes and one Eclipson Blackwing, but this is by far the best designed and most thoroughly thought out 3D printed plane I have ever owned. Well worth the price (acutally - I think it's bargain).

Great design, great STL files, looks majestic (in my living room for now :-D - I'm about 80% done with printing, and haven't even started on electronics and motor).


Typically 5 minutes from takeoff to touch down. 8 minutes is possible.

Done! Just wait for a suitable weather for the flight. What is approximately 12S 5000 mAh flight time?

Do you have in mind the next model you are going to design ?, a beautiful plane would be the f100 for edf 120mm

hello I wanted to know how he was able to drill the motor shaft. It has some illustration.
I also wanted to know if you have thought about doing a 90mm edf design

They slide into the inner wing panel and glue in plac with CA.

I'd like to have this is 80/90mm EDF version, is that possible? If so, do you know what the scale down should be if I were to purchase?

Thank you. Not reinforcement, but servo holder will be required. I cannot find any mounting surface for so oriented servo. There are only sharp edges to which nothing can be screwed.

I added a photo of a installed flap servo. If the mounting surface is too thin becaseu fo too few layers you can glue on a reinforcement on the surface.

I'm sorry, but I need to make it clear. Is the servo bolted directly to the lower surface of the wing perpendicular to it? Elsewhere there is not enough material for the screws.
In "Mainwheel01-bb", the bearing size of 4x7x3 is probably given incorrectly. The slot is for 4x8x3 bearings.

The flap servos mount in the root end of Wing02-flap and don't need a hatch.

Is there a "servohatchflap" or something else? How is the flap servo mounted in the wing? Is photo possible?

Hi, alu tubes have not the same stability like carbon tubes. The risk to loose the wings is much greater.

hi great model busy printing it, but there's one thing can I use alu tubes 13mm instead of carbon? just for the wings?

Hello, as first I would like to say thank you for perfect model. I have just one question. I have printed front and rear Vstab but Vstab02 - Bottom rear part of vertical stabilizer looks higher then front part approx 3-4 mm. Is it for some reason or I did something wrong?


That's great to hear. :)

I will try to use even dimensions in the future. Many people have requested this.

If i could say a wish, so please use even values mm for the big carbon tubes. The 9mm, 11mm and 13mm are extremely expensive.

Hello, yesterday the 23.10.2019 was my maiden fly, and it works great. only a little trim down and right. Then i fly full speed and 150m loop, immelman, rolls and .....
Perfekt handling from the first second! The landing with full flaps was even so wonderfull. I mixed 2mm elevator down to the full flaps. My cg is 93mm. The take off weight is 8050g. The fan is an 120mm Jetfan. The esc and motor are the like discription.

Thanks for the great constraction

OK, thank you

Printing Fuselage01. The "Canopy latch assembly" image shows the green part of the air inlet. It is not on the printed part. Is it printing separately? What is the file name? I couldn't find it. Thank you.

I bought your model today. What layer height do you use, 0.2 or 0.25 mm?

Ok thanks alot i will "save" the piece which ive already printed and print another one later.

You're right. I hadn't noticed. 3DS Max removed most of the internal when I created a new boolean modifier to cut out the latch. Thanks for letting me know. I reuploaded it.

Just a quick question regarding fuselage01-latch, in cura im missing the inner boxes in nose part, 3 on each side i think. Ive seen pics from you with them clearly visable. Can you verify the part being correct ?
Might be cura thats showing it wrong but dont think so. Ive printed it and it was no surprice it got a bit saggy without the inner boxes or beams,

All the best

I've printed two big parts of the plane and i must say realy nice job what you did ! Perfect design ! Thanks


If you downsixe it by 10% then the retract units, shocks carbon fiber tubes and rods won't fit so you'll have to figure out how to replace them. Should be doable but it will need some work.

The only parts you will not be able to print at 100% are Wing01-flap Fuselage01, Fuselage02 and Fuselage03. You can split them up in two pieces each in meshmixer for example which will work fine since you have a printer that's tall enough to print full height.

Hi, I have a printer with a build plate of x=300 y=220 z=300. Can I scale the parts down by 10% or is there any way of printing it at 100% with my build plate size?

man, is it possible to print it out on a 190mm by 190mm by 190mm printer?

Sorry. It requires a lot of design work to make that happen, and the largest parts will need to be cut into five to eight smaller pieces to fit on a smaller printer. Imagine a 30x30x30 cube being cut down to fit 200x200x200. It needs to be cut into eight pieces to fit the smaller size.

is it possible for you to do a download for me to split the larger parts to fit a printer with a 210mm by 210mm by 205mm thanks colin

Is it possible for you(the designer of the plane) to send me the STL files of the tail fin in a fewer number of pieces? please? Thanks

perdona aqui estan todos los archivos imprimibles para crear el avion

Wheel can be printed with maybe four perimeters and maybe 50% infill. Just make them strong.

For tires I use two perimeters and maybe 10% infill. It's very printer and filament dependent. I need a lot of top layers to close the tires.

How many perimeters did you us for the wheels and did you use any infill? Thanks

The canopyplugs are for fabricating plugs for vacuum forming canopy glass. They can also be used to print separate pieces for the glass so that you can make a cleaner looking printed glass than the one made along with the frame. You don't need to print them to finish the plane normally.

Do I need to print the "canopyplug" parts, and what are they for.

I haven't changed anything in a long time. You should get the newest revision if you download now.

There in my account have the option to recover the purchased files, are these files already up to date? Thanks in advance ... thanks !!!

Hello friend I did the previous purchase the updates, could you provide me the updated files?

One 0,4 mm perimeter and 0% infill for all the large parts.

Hi guys, I'm having trouble printing the fuselage. So i'm wondering what percent of infill did you use and how thick should I print the walls?

many thanks
i have find in your country good engine
Het Typhoon 800-68/685 on 12s (huge C) produced static thrust about 9,5 kg/ 6700W power
where i can buy it

There is no separate intake. The intake is integrated in the fuselage and adds to the structural integrity of the plane.

I have not found the file of the two input air in Y form to input air from outdoor to turbine

I have never flown turbines myself but I think it's possible if you can shield the plastic from the heat. There is a lot of room behind the cockpit for a custom tank or bladder tank.

Hi, I'm interested in your EL-39 rc plane. it is possible to adapt it for Gas turbine class 100?

Castle Creations 2028 probably won't fit because it's too big. 800kv is too high for 12S. Maybe with 8S, but the current draw will have to be 125-130 A to achieve the same power. It is also a much more expensive motor than the HET 800-73-590.

can you give me your opignon to introduce EDF castle 2028 in housing and fan 3d printing? in your L39 model ALBATROS
castle 2028 with manbaXL BEC
power 10ch
800kv max rpm 45000 length 113.2 mm diameter 57 mm axe 8mm lenght axe 30 mm
i want use blower for this motor it's with 2 fan lower motor temperature as much as 30 degrees
lenght 89mm width 60.5 mm height 57.5 mm
best regards

I have some interesting news. I figured out why the part was buckling, in Simplify3d under the ADVANCED tab in the lower right corner I had MERGE all outlines into a single solid model. That caused me a lot of issues with the buckling. So after unselecting it I did quite a number of tests today with both printers. I confirmed somethings very interesting. First I confirmed that with 0 infill and 0.4 layer height the models printed can be used per the author. The part I printed ( a single horizontal stabilizer ) using the settings just mentioned in PLA weighed in on the scale at 40 grams. However I did not give up on PETG, instead I printed the same part with 0.2 layer height and 8% infill - the part is MORE rigid than the PLA version and weighs also 40 grams.... So that was a big WOW moment for me.... I currently have another idea for PETG zero infill with double outside parameters and 0.4 layer height. So I'm trying that out now, and should have a weight on it soon. There is ZERO flex printing PETG with 8% infill and it looks AMAZING. It looks right now, as though I will be going the PETG route for my build due to the better heat tolerances for outdoors, plus it looks SUPER cool... One thing I have noticed though doing this is I need to get TL Smoothers for my drivers to get rid of the salmon skin. It would look cool if I was using a wood filament, but the PETG black I'm testing with looks like Carbon Fiber and the salmon skin / wood grain effect doesn't suit the plane.... =) Sorry about all the posts, I just wanted to share my experimentation with the community

I didn't weigh the parts so I don't know what they all weighed. The airfrane should be printed with 0% infill. If you get buckling you need to work on your settings. Probably too hot nozzle or bed.

If you could provide the weights that would be great. I did quite a number of test prints, with PLA and PETG. I had to use 4% infill on PLA with 0.2 layer height to get a structure I was happy with flying as well as 1 outside perimeter. With PETG I used 1 outside perimeter and 10% infill , 0.2 layer height - provides a REALLY nice finish. Here is where the interesting thing comes in, both weighed in exactly at 44 grams. The PETG at 10% was VERY stiff and firm, no flex at all... This was using budget refill PETG and PLA so nothing fancy.

I thought it was good results, I wish I knew the weights in grams on all the parts - it would make it easy to know how the infill affects overall weight, I can than scale it up to see how much the model will weigh in the end with this weight for PETG.

Right now, if the weight is on spec I will go with PETG for most of the build , the look of it as well as the stiffness I have achieved in the structure I am now happy with it. I am thinking about going to 8% infill for a test as well. I was not happy with 5% infill there was too much flex. I think 8% would be the lowest I would go with this part.

I printed only one side of part Hstab02.stl - I would be curious to know that one in grams right now to see if I'm on track. If the author could provide the weights to the parts that would be helpful. If the part stl file has two pieces, left and right side, if the weight could be broken down for one side, that would be also a HUGE help.

I am happy to provide my data to the community to help people decide if they want to print in PETG vs PLA as well. I will do up a video to show the group tomorrow and place it on youtube to show the difference in flex from 5% PETG, 10% PETG and if I print another this evening 8% PETG

I have PLA 4% here as well. I am not doing the one perimeter vase mode, the buckling in the stabilizer was horrible, no much support there for my piece of mind.

I can't find the weights in grams for each of your components - I thought I saw it somewhere, can you provide the link please...

Just finished single perimeter wall on PETG and PLA - PETG was way way way too flexible with single wall, the PLA was better however both prints of the same piece (horizaontal stabilizer) bowed inwards due to the fact there was no infill, there was nothing there to support the piece since it was printed basically in vase mode. Both the PETH and PLA did this, with PETG doing in more than PLA. I am currently redoing the print with 5% infill on both PETG and PLA. These tests today should show me which filament I will use for the build. I am still hoping for good things with PETG, I haven't given up, I will weigh the parts as well to get an idea how much they weigh vs the authors weight with the infill added to both types of filament.

I just started printing PETG on one printer and PLA on another, using the horizontal stabilizer as a test part (fairly small part) will show the difference to me in the materials for usage. I did a test print last night , but after checking my details I say it was .2 layer height not .4 so maybe that accounts for the flex and weakness in both prints I am seeing this morning, so I reset the print to go at .4 for both of them, I also changed top and bottom layers to 4 instead of 1, with a single perimeter wall in simplify3d. I should see my next test this afternoon. I needed to do this before I commit to buying many rolls of either pla or petg. Right not, things are not looking good for PETG. We shall see soon...

it's easy no problem for me to separe 2 parts only one
for fuselage 05 part i think good filament for resist in hight temperature is polycarbonate filament
i want tested this solution

Click "mesh" and then "Separate Connected Surfaces" in Simplify 3D. IT will split the parts up in all its unconnected pieces and you can move them around. Make sure that any internal objects that are separated also are moved when the main object is removed, as it will separate pockets as individual parts.

I made the files like they are to reduce confusion and keep the file count down. I arranged them in the same groups that I use to print myself.

I purchased the STL's but I'm noticing that all the stls when you open them up have two parts for example with the wings, it would be big benefit to have singular parts to make it easier to print. Can you do this as I cannot remove one from the slicer (Simplify3d), when I select either part and press delete it removes both...

i have transformed stl in G code with simplify 3D filament 6 kg and 620h print time
it's first result we can optimise certain part
time for print is not a problem for me i have 8 printer bigest is 600x600x600 other 320x320x400......

Four kg should be enough if all goes perfectly.

How many spools of PLA ( estimated if you don't remember ) did it take to print this aircraft ? Just purchased the stl's and I need to order spools for the build.

I haven't used a turbine in mine so I don't know what the xhaust temp would be. You can see many videos of my plane that demonstrate how the landing gear holds up to hard landings.

I am preparing the 3d printing of your L-39 model
can help me find a supplier of carbon tubes
do you know the temperature at the turbine outlet and its maximum operating temperature?
see the series of photos
I have some concerns about the performance of landing gear in 3d printing
I'm looking to equip the jet with a metal landing gear
thank you
kind regards

Translated with

Welcome !
My question would be how much 3D printing would cost me home. I have a CR10 S5 printer and I would like to print this model. But I do not know how much it would cost me and what material I would use because I want to try 3D printing for the first time. I like Challenges and Airplanes.
If you would please and help me in this I would thank you.
Welcome to Csanád Gál

Check the files for updates and you will find a new wheel with ball bearing pockets. :)

New update: test taxi runs have gone great! Found a little flaw. Going back and forth a few times at high speed, heats up the axle and melts the main strut after some long runs down the runway. I’ve fixed it since and finishing the gyro setup. Hopefully next week I can maiden it.



good afternoon I wanted to buy the files for the L39 my printer has an area of ​​210 * 210 * 205, can scale to this dimension, or sell the cad, wanted to use a 90mm EDF.

It's 1:6,5 size. I cut my own paint stencils with a vinyl cutter.

Got the retracts all working. I'm looking at some graphics, but what size is this? 1/6? I thought I saw on another site as 1/6.5. Thanks for the help as usual!

Ok, I'll try it out. I'm using a 6.6V LiFe. It's getting close!lol

No they don't need a sequencer. What voltage did you try them with? Try spinning the shaft a little first to bring the unit out from the end point.

One of mine had a tendency to stick on one end because the magnet in the moving beam was too far away from the circuit board. I pushed the magnet out and that fixed it. It shouldn't be necessary though.

Hey bud, I bought 3 of those retracts from HK that you linked too, and I tried to use a servo tester on them. They didn't work. Are these the type of servoless retracts that need a sequencer to work? I'm stumped. I even tried using three different servo testers.

Maingeardoor01 contains both parts attached to the main gear. Maingear02 and 03 are the inboard doors.

what's the name of the stl file that has the main gear covers? Not the main gear doors. Thanks!!

Everything is all printed up! Now just getting in the parts to finish it. All the guys fly at my field are turbines and 90mm this size, and no one has an extra 120mm edf laying around!!lol For now, I'm saving for Jetfan 1120 pro and the HET 800-72-590. At least that is the plan!!lol Servos are coming in soon as well as, the carbon fiber rods. Also have to wait for the servoless retracts to come in. Damn! So much stuff to buy, no time to wait!!lol

Thanks as always!


They should fit in the bay. The width should only just fit but there should be plenty of room for the diameter.

The 3D printed tires on my EL-39 are quite hard. It's a heavy plane.

I've tried using flexible filament before, but in the humidity of South Florida near Ft. Lauderdale, you can't get the same flex as you could being up north! To much moisture, unless you have a perfectly controlled room an temperature. I just ordered the same size from Tower hobbies. Robert wheels model ROBQ1534. They sure look like the same size!!lol

If you were going to choose a robart main wheel, which would you use? It's my only hiccup now.

It's possible to make Robart 669L and 669R spring struts fit. They need to be cut and bent to fit. Other struts may fit, but I don't have any to test with. The printed struts are very strong. Check out my videos. I make a few very hard landings and haven't had any failure of the main landing gear yet. The nose gear is more fragile, but should never be the first thing to hit the ground.

The nose wheel is 60x20 mm. That's the max size that will fit.

The main wheels are 85x22 mm. The biggest you can fit is ~85x24 mm

What size is the nose wheel, if I were to buy one, and what size main gear wheel?

It doesn't go inside Nosegear04. It goes inside Nosegear03, and then Nosegear04 goes inside 03 on top of the shock. I attached a photo in the Thread on RCGroups.

The hex nut is the same as the outside width of that cylinder it needs to go inside. I must be missing the step. The graphic shows how it goes together, but what does you hex nut look like? Is it in a file I'm missing?

I do have a question regarding the nose gear. I have printed most of the pieces for it and I'm not sure if the shock absorber goes into nosegear04. Because the shock you told me to get, doesn't fit in it. Any pictures, not the computer pic, that shows you doing it would be great!!!

Thanks again!


I added two photos now showing the inside of the nose and main wheel wells wher ethe door servos reside.

You know, after I wrote that, I thought that was what they were for!! Not technical!!!lol Are there any pics of how you attached the servo to the nose gear door/ main gear doors? And how you put the servo in and how the retract looks, up? Any pic that is a close up of major parts, would be perfect! Also, if I can't print the landing gear to be good enough, like yours, do you know of any links for ones that might be bought online? Thanks again!
Awesome jet!!!

Those are there to support the center piece as it's built from a tiny surface up. I could not get it to print without them. Just snip them off after printing that section. They will leave minimal spots to clean up.

Ask away. There are probably more people wondering about things, and I don't know about all the things that need explaining.

I am following that thread! Pictures are a big help for me. Not a very "technical" person. I've adopted the "keep it simple" approach!!LOL Now one more question and I'll be out of your hair, what are those 6 ovals, almost floating, in the air intakes? Did I skip something in the thread regarding them?
Thanks for all the help!

Thank you, sir! Now, if I can figure out your nose gear door, I should be ok.

Thanks again!

Thanks for the response! What is the name of the file for the top piece of the tail? In your picture above, it is the part above the purple section. I have the two tan/brown pieces, the red and the purple, but not the pink top. Sorry to be a pain!!

Hi, Larry. There is no third part of the rudder. It got added to the list of parts by mistake. :) The rudder only has two parts.

Awesome L-39! I bought the files, but it seems to be missing the rudder03 in the downloaded files. Last part I need to finish the tail!! Any way I can get that one?

Hi, really nice model and good idea. I have buy your plans, but it's a little difficult how to assembly, specially the nose gear. Could you upload one video explaning how it is the correct way to assembly and especially how work the nose gear steering system? I have to buy 3 units of 90 degree retract servos, with no integrated steering, right?



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