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
Appropriate pilot figure:
Video of the prototype without flaps:
High speed fly bys and landings compilation:
Various flight videos:
-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: https://www.e3printable.no/nettbutikk-norge/14-pla/539-pla-175mm-1kg-lys-graa/
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: https://files.cults3d.com/uploaders/12943812/illustration-file/5b7c37a2-fb2e-4132-8198-a63abb9d6e14/EL-39-84.jpg 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: https://rover.ebay.com/rover/1/711-53200-19255-0/1?ff3=4&toolid=11800&pub=5575353675&campid=5338226872&mpre=https%3A%2F%2Fwww.ebay.com%2Fitm%2F102004-Shock-Absorber-HSP-RC-On-Road-Car-02002-02175-Upgrade-Part-122004-1-10%2F264063176330
Springs 1.8x18x35 mm for the main gear:
10000 CST diff oil for the shocks: https://rover.ebay.com/rover/1/711-53200-19255-0/1?ff3=4&toolid=11800&pub=5575353675&campid=5338226872&mpre=https%3A%2F%2Fwww.ebay.com%2Fitm%2FTeam-Associated-Silicone-Diff-Oils-various-cst%2F153641530179
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: https://www.banggood.com/Corona-CS238MG-Thin-Metal-Wing-Analog-Servo-p-1049129.html?p=HD240528697332015103&custlinkid=367343
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. http://www.castlecreations.com/en/talon-hv/talon-hv-120-esc-010-0131-00
The prototype flies with an Aerostar Advance 120A: https://hobbyking.com/en_us/aerostar-advance-120a-esc-opto.html?affiliate_code=BSFWYBUNYWDKXJN&_asc=5830570510
-Extra capacitors with low ESR for the ESC because of extended battery wires. At least 660uF total extra capacitance: https://www.digikey.no/product-detail/en/63ZLH470MEFC12.5X25/1189-3033-ND/3564146
-Retract and door sequencer: https://hobbyking.com/en_us/turnigy-smart-retractable-landing-gear-gear-and-door-sequencer.html?affiliate_code=BSFWYBUNYWDKXJN&_asc=4305082623
-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): https://hobbyking.com/en_us/turnigy-90-degree-all-metal-servoless-outward-operating-retract-unit-90-size-1pc.html?affiliate_code=BSFWYBUNYWDKXJN&_asc=9928784058
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 Airplane.zip - Old Simplify 3D profile for fuselage sections with JGAurora A5 printer.
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.
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