Official Freewing 80mm EDF L-39 Albatros Thread

[steven gubala]

Thanks Monty500, will check into it

[pilot2fly]

Hi there, does anyone know the color code for the red on the red/white/blue version of the L-39? I'm trying to find a matching or almost matching spray paint. I want to paint the fuel tanks red and repaint the blue part of the wings red.

[Joehockey]

I am on my second fuselage and looking for some expert advice. I fly with Graphene 6 cell 5000 packs and they are heavy. I know that CG is CG so it’s up to me to make sure I get it correct. Considering I have to disassemble the model to replace the fuselage I am considering moving some things around.
Can anyone show or post a pic of what they feel is the ideal CG on this model ? Jets really really struggle at our field to take off, while its well maintained, jets are Legendary problems at my field. So , CG is not only critical for proper flight but its critical in relationship to a successful take off .

Most of us are forced to rush lift off in order to keep from running out of runway ( not good ) , also depending on the wind, one end of the runway is a cliff !

I am not sure that the Graphenes are simply too heavy for this bird and really inhibiting lift off but its been a crap shoot on take off runs !

[xviper]

I am on my second fuselage and looking for some expert advice. I fly with Graphene 6 cell 5000 packs and they are heavy. I know that CG is CG so it’s up to me to make sure I get it correct. Considering I have to disassemble the model to replace the fuselage I am considering moving some things around.
Can anyone show or post a pic of what they feel is the ideal CG on this model ? Jets really really struggle at our field to take off, while its well maintained, jets are Legendary problems at my field. So , CG is not only critical for proper flight but its critical in relationship to a successful take off .

Most of us are forced to rush lift off in order to keep from running out of runway ( not good ) , also depending on the wind, one end of the runway is a cliff !

I am not sure that the Graphenes are simply too heavy for this bird and really inhibiting lift off but its been a crap shoot on take off runs !

It is well known that HobbyKing Graphene (or any other Graphene) batteries are much heavier than other non-graphene type of battery. I've always bought Graphenes with that in mind. IE, if I'm after a 2200, I buy 1800; if I'm after a 3500, I buy 3000, etc. The 5000mah Graphene, 6s is more like a 5600 to 6000 mah non-graphene. However, I doubt that an extra 150g to 200g on THIS plane is going to make a huge difference in take off distance. Try a lighter battery just to see. If it does make a difference, then an option may be to put in a higher thrust EDF (like an inrunner from FMS if it doesn't have one already) and always use a high "C" rated battery.
As you say, CG is CG and I've stuck with the manual recommended CG for GeoTex, smooth grass and rough grass and the longest this plane takes to left off is about 200 to 250 feet on very plush, unmowed grass. Do you use 1/2 flaps for take off? This can help greatly for this plane. Do you use high rates on the ELE for better rotation? Sure, you could move the balance point further back to get it to rotate sooner, but then, you may be dealing with a tail heavier plane that becomes twitchy in the air. The old adage "A nose heavy plane will fly. A tail heavy plane may fly only once." may be true for this plane.

[Joehockey]

All good points and I appreciate the feedback. I do have the option of a lighter pack to test but obviously less flight time.
As far as flaps, 1/2 flaps was the reason for an early lift after two attempts. The president of our club is by far the most experienced pilot, having flown everything from 45lb birds to turbines.
I gave him a shot with a fresh lipo after two attempts on my own. He did everything possible to take off with 25% flaps, good clean straight run and this thing hugged the ground like a baby hugging his mommy on the first day of school !
I change out another pack and was determine to do my best to forces it into the air but attempt to keep control. Unfortunately it did what I wanted, lifted off but without proper airspeed, and my best efforts to prevent a stall failed.
The fuselage is repairable but at the cost of adding weight to a model that should not gain an oz in my opinion.
Based on my investment I may take your suggestion to increase the power via the ducted fan.
Viper do you have a Inrunner you suggest ?

[xviper]

I do have the option of a lighter pack to test but obviously less flight time.
Yes, it's just for "testing" to see if weight is a factor. If it is, then buy lighter packs that are still 5000mah. Most non-graphene LiPos are 150g+ less weight than HobbyKing Graphenes.


As far as flaps, 1/2 flaps was the reason for an early lift after two attempts. The president of our club is by far the most experienced pilot, having flown everything from 45lb birds to turbines.
I change out another pack and was determine to do my best to forces it into the air but attempt to keep control. Unfortunately it did what I wanted, lifted off but without proper airspeed, and my best efforts to prevent a stall failed.
This is where the "experienced" pilot should have known what to do. As soon as the plane leaves the ground, you must immediately level out and stop it from continuing to climb. This allows for more airspeed very quickly before you try to climb. I am surprised that your club president was not doing this.


Viper do you have a Inrunner you suggest ?
Yes, I have the FMS 80mm 2100kv inrunner in mine. I put that in after I had flown it stock for about 1/2 a season. I did it not to get off the ground any sooner but to get a little more speed in the air. It did shorten the take off run by about 50 feet. You can buy it via your local hobby shop from Horizon Hobby.

[Joehockey]

Thanks I will look into the upgrade considering I making another $100 investment in the new fueslage. The Club Pres is very experienced, I think everyone flying electric jets at our field, the model really took him by surprise.

[Radar-Guy]

Here's a take-off from grass, Wemotec 80mm Midi Fan Evo, HET 700-65-1865, 120A ESC, 8s 4500mAh

[xviper]

Thanks I will look into the upgrade considering I making another $100 investment in the new fueslage. The Club Pres is very experienced, I think everyone flying electric jets at our field, the model really took him by surprise.

Please note: The FMS fan unit doesn't mount perfectly flush. It' a couple mm larger in outer diameter, so you either have to shave off a little foam around the fan or you just mount it and deal with the small ridge due to the fan hatch not sitting flush. Since that area is red, I didn't bother with shaving foam. I just covered the seam with red tap. If that bothers you, then you'll need to do some shaving, but since you're dealing with a new fuse, it shouldn't be too much of an ordeal to work with it before everything else goes into it.

[xviper]

Here's a take-off from grass, Wemotec 80mm Midi Fan Evo, HET 700-65-1865, 120A ESC, 8s 4500mAh

Yup, mine with the FMS EDF takes off about 50% longer distance, still very short.

[Evan D]

It's about a mm all around. Instead of taking and sanding away a mm I sometimes just take my thumb and compress the foam a bit.

[Joehockey]

Thanks for the help guys , I ordered the FMS upgrade from RC Castle , so lets hope 2021 brings grass opp success

[Monty500]

Successfully maidened my Camo in-runner L-39 earlier today, with 3 flights in total. Started off with cg at the recommended 103mm and moved it back to 107mm for the second and third flights. I may move it back further as I get used to the model. Most of today’s flying was at mid throttle (~60%) and the L-39 seemed pretty quick and stable at this throttle setting. It accelerated well at full throttle with very good vertical performance.

Interestingly the all up weight including LiPo is 3.15kg, exactly the same as my Stinger 90 with the same LiPo (Turnigy Heavy Duty 60C 5,000mAh – 790 gms).

All flights were at mid rates which were in line with what posters like Herb have recommended:

Ailerons: 15mm
Elevator: 20mm
Rudder: 30mm
Flaps: 15/25 with elevator mix per the manual

I am using an AR7350 AS3X receiver and need to play some more with the rate gains but started off with two very conservative gyro settings and a gyro off setting.

• Low rate gains of 20 Ail, 25 Ele, 30 Rud and 160% priority
• Higher rate gains of 30 Ail, 35 Ele, 40 Rud and 160% priority

This morning’s flights were in dead calm conditions so will tune the gain settings over the next few flights. There was no oscillation at higher speeds so will increase the rate gains in future.

Mod’s include:

• RC Geeks afterburner
• Additional belly and dorsal strobes (bought the led lighting kit for the Freewing F-4 and utilised the double and triple flash connections in the blue box)
• Mesh grill over the cheater (thanks to Herb for his advice on this)
• Painted the servos and linkages to match the surface colours

I did have one assembly issue as the starboard landing light doesn’t work. I have rechecked the wing tank to wing connections and the connector at the center of the wing also looks fine. Maybe a dud led is the issue?

[steven gubala]

Monty500, where did you get the mesh grill for the cheater?

[Monty500]

Monty500, where did you get the mesh grill for the cheater?

Hi Steven,
I bought a cheap flour sieve from a homeware store and cutout the mesh. Then made a paper template and glued the mesh to the plastic cheater grill with UPU POR glue.

[steven gubala]

Thanks Monty500, will be making me a mesh grill for mine

[Sniper93]

I have the pnp camp version of the freewing L 39 the landing gear does not come down. Anyone else have this problem ?

[xviper]

I have the pnp camp version of the freewing L 39 the landing gear does not come down. Anyone else have this problem ?

There is a delay due to the sequencer. How long did you wait after you threw the switch? Is the lead for the gear plugged in with the proper polarity?

[pavcon]

ordered this on Sunday. can't wait for it to arrive. 2.5years without flying is too much.
hope it helps me get back to it soon.
couple of questions. how much time does it take for motionrc.eu to ship their products?
and I have ordered the 5100 70C packs. and they were a tad heavier than 6000mah 40C. I hope I have done well.
also ... I read around and see people swapping the stock EDF units. I know the wemos and used to own when I was flying . they do offer better efficiency, but I wonder how much better they are than the performance version of the plane.

[Radar-Guy]

ordered this on Sunday. can't wait for it to arrive. 2.5years without flying is too much.
hope it helps me get back to it soon.
couple of questions. how much time does it take for motionrc.eu to ship their products?
and I have ordered the 5100 70C packs. and they were a tad heavier than 6000mah 40C. I hope I have done well.
also ... I read around and see people swapping the stock EDF units. I know the wemos and used to own when I was flying . they do offer better efficiency, but I wonder how much better they are than the performance version of the plane.

Usually MRC EU ship within a day or two, but it might take longer due to the extra efforts caused by „Brexit“ these days.

70C packs take a lot of caution to keep (pre-heating, precise charging, correct storage) them 70c packs, otherwise you‘ll own „ordinary“ 35C packs soon.

The current 6s inrunner stock fans are absolutely sufficient for the L-39 to fly in a scale-like manner. I flew a Schübeler 6s and Wemotec 6s (2100kV motors) in my L-39, no noticeable performance change.