Aero L-39 Albatros V2 - EDF Jet

Grifflyer

WWII fanatic
The damage really wasn’t that bad. I glued it all back together and flew it again today. Went better this time. It’s fairly quick. And you have to keep the speed up when banked over pulling in a turn or it does a weird stall. My 50mm L-39 would do the same think but at a much lower speed. I’m sure it’s just the weight of my battery. It’s probably a little big for the plane.
Mine does that as well, I think it's just a flaw somewhere in the design. It's not too big of an issue for me, I just make sure I have long straight landing runs to avoid the weird stall
 

jfaleo1

Junior Member
The damage really wasn’t that bad. I glued it all back together and flew it again today. Went better this time. It’s fairly quick. And you have to keep the speed up when banked over pulling in a turn or it does a weird stall. My 50mm L-39 would do the same think but at a much lower speed. I’m sure it’s just the weight of my battery. It’s probably a little big for the plane.

That is interesting I had no notice a high speed stall or a banking stall on mine (50mm or 70mm) but that may be because i never had the position and speed combo to cause it. Or the different tips I am using change the wing a bit.

Glad to hear you are up and running again.
 

Grifflyer

WWII fanatic
That is interesting I had no notice a high speed stall or a banking stall on mine (50mm or 70mm) but that may be because i never had the position and speed combo to cause it. Or the different tips I am using change the wing a bit.

Glad to hear you are up and running again.
It only happens to me when I'm low speed coming in too land
 

Guy S.

Well-known member
That is interesting I had no notice a high speed stall or a banking stall on mine (50mm or 70mm) but that may be because i never had the position and speed combo to cause it. Or the different tips I am using change the wing a bit.

Glad to hear you are up and running again.
I've flown my 70mm 5-6 more times since i put it back together. its flying much better now. After i posted about the weird behavior, and the "stall" i gave it a closer look before i flew it again. Looks like i did a poor repair, and the wing had come unglued on one side. if i didnt keep the speed up, and thus the G's holding the wing on it was flying "weird" go figure. lol I properly attached the wing and it's all better. ;)
 

OliverW

Legendary member
The stall would make sense since the wing has no undercamper, but there's no way to put in undercamper and have the wing tanks
 

Cycle Pilot

Member
So, I just finished building my upscaled version of this plane. Just needs some paint. I've flown the heck out of my 50mm and it's one of my favorite airplanes. Flies beautifully! Here are the specs on my 70mm...

Empty Weight: 800g
Motor: FMS 1900kv 70mm 6S
ESC: Skywalker 80A
Thrust: 2600g
Battery: Spektrum 6S 3200mah (487g)

This plane should be WAY overpowered for the weight of it. Target power for this size of plane should be around 600W and this motor puts out 1500W at full power! I'm guessing it's going to haul butt. My only concern is hand launching this big of a plane. It took some practice but I got really good at hand launching the 50mm. We'll see how it goes. Here's a list of some changes I made to the design with the upscale:

- Embedded a skewer into horizontal stabilizer for strength. This plane is going to have much more load on the surfaces so I wanted some strength.
- Added skewers to the insides of the sides of the fuselage.
- Added some aero to the inside of the intake to make for smooth airflow into the motor.
- Upgraded all of the servos to 9g metal gear.
- I added a rudder to my 50mm and did the same to the 70mm.
- Going to add 3D printed skids to the bottom of the plane to protect the fuselage for belly landing. My 50mm is tore up!

Here are a couple of pictures...

PXL_20201215_083832006.jpg


Here's a picture of the skewers for the fuselage. I hot glued them in place and taped them. Much less flex in the nose now.

PXL_20201215_083739959.jpg
 

Grifflyer

WWII fanatic
So, I just finished building my upscaled version of this plane. Just needs some paint. I've flown the heck out of my 50mm and it's one of my favorite airplanes. Flies beautifully! Here are the specs on my 70mm...

Empty Weight: 800g
Motor: FMS 1900kv 70mm 6S
ESC: Skywalker 80A
Thrust: 2600g
Battery: Spektrum 6S 3200mah (487g)

This plane should be WAY overpowered for the weight of it. Target power for this size of plane should be around 600W and this motor puts out 1500W at full power! I'm guessing it's going to haul butt. My only concern is hand launching this big of a plane. It took some practice but I got really good at hand launching the 50mm. We'll see how it goes. Here's a list of some changes I made to the design with the upscale:

- Embedded a skewer into horizontal stabilizer for strength. This plane is going to have much more load on the surfaces so I wanted some strength.
- Added skewers to the insides of the sides of the fuselage.
- Added some aero to the inside of the intake to make for smooth airflow into the motor.
- Upgraded all of the servos to 9g metal gear.
- I added a rudder to my 50mm and did the same to the 70mm.
- Going to add 3D printed skids to the bottom of the plane to protect the fuselage for belly landing. My 50mm is tore up!

Here are a couple of pictures...

View attachment 186288

Here's a picture of the skewers for the fuselage. I hot glued them in place and taped them. Much less flex in the nose now.

View attachment 186289
Dang that thing is going to be an absolute rocket ship!!
 

Intashu

Elite member
Went to fly mine yesterday, I did a few things wrong which resulted in a lawn dart and needing repairs already. I stuffed a 2200mah 3s battery in there and I think that makes it a little too heavy for the power provided, I got a 4s ordered and on the way however! but most importantly I did not throw it nearly hard enough, so it never got the necessary lift to get going. Got it patched up later last night so it's ready to fly again, unfortunately in my repair the canopy does not sit as perfectly as it did before. But I got magnets to keep it in place.

Cold weather here in MN prevents me from flying too often this month, Hopefully I'll see a better day soon to get a proper maiden flight in!

All I got is a potato quality photo here pre-crash. post fix the nose is SLIGHTLY off center. and I noticed viewing this thread that I rounded out my canopy a lot more than other builders.

If I get a successful maiden out of it I may rebuild the nose and canopy entirely to straighten it out and make it a clear canopy with 3d printed interior.

I intentionally did NOT reinforce the nose parts yet because I figured I would likely crash it, and didn't want to cause major damage to the main fuselage parts. It's clear however that yes it absolutely needs a paint stick in it or something for normal use!
 

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Grifflyer

WWII fanatic
Went to fly mine yesterday, I did a few things wrong which resulted in a lawn dart and needing repairs already. I stuffed a 2200mah 3s battery in there and I think that makes it a little too heavy for the power provided, I got a 4s ordered and on the way however! but most importantly I did not throw it nearly hard enough, so it never got the necessary lift to get going. Got it patched up later last night so it's ready to fly again, unfortunately in my repair the canopy does not sit as perfectly as it did before. But I got magnets to keep it in place.

Cold weather here in MN prevents me from flying too often this month, Hopefully I'll see a better day soon to get a proper maiden flight in!

All I got is a potato quality photo here pre-crash. post fix the nose is SLIGHTLY off center. and I noticed viewing this thread that I rounded out my canopy a lot more than other builders.

If I get a successful maiden out of it I may rebuild the nose and canopy entirely to straighten it out and make it a clear canopy with 3d printed interior.

I intentionally did NOT reinforce the nose parts yet because I figured I would likely crash it, and didn't want to cause major damage to the main fuselage parts. It's clear however that yes it absolutely needs a paint stick in it or something for normal use!
Ugh that sucks, this thing has such a small wing that if you don't absolutely chuck it, it'll take a dirt nap. Yeah the nose needs some reinforcement. If you don't crash it's fine but after 30 or so nice landings,stress marks will start showing up. So I'm running one popsicle stick to strengthen the area.
 

Intashu

Elite member
Yeah, so 4s is ordered, figured I PROBABLY could fly it on a 3s full throttle.. It kinda flew... I know it WILL fly.

I also know I'm building a new nose this evening.
 

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Grifflyer

WWII fanatic
Yeah, so 4s is ordered, figured I PROBABLY could fly it on a 3s full throttle.. It kinda flew... I know it WILL fly.

I also know I'm building a new nose this evening.
Awwww not enough power I assume? That's too bad it was such a beautiful bird!
 

Intashu

Elite member
Awwww not enough power I assume? That's too bad it was such a beautiful bird!
Yeah, it had JUST enough power to level out.. attempting a turn it promptly lost the 10 feet of altitude I had and cartwheeled into the ground. I think the canards helped bounce it so the rudder/elevator didn't get damaged. It's wrinked but I'll build a new nose for it like I figured I was likely going to have to do, 4s lipo arrives early next week.

I looked back through this thread and found someone's stl's for a 70mm EDF... so I printed that to test out too.. havent even gotten this one to really fly and I'm already planning my next EDF jet...
 

Intashu

Elite member
Aha! I got it!

Light snow falling didn't stop me from trying again! Hit a rock on landing (no major damage fortunatly) but I got her to stay airborne finally! :)
 

Llamaman197

New member
Hey, saw that everyone is getting 70 mm plans. Could I get some? Also long time ago tried to scale up the original to 70mm but I couldnt figure how to put it together. Is there a tutorial or some way to figure it out?
 

Oldrover TJ

Active member
I've been flying the wings off my L 39, quite literally. I had some delamination along the wing root and when I started to repair it I noticed more delamination along the main spar. I decided to remake the whole wing. I wanted to add some winglets and change the camber profile of the wing.
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20210505_124733.jpg
 

dehager

Well-known member
My first L-39 has finally been retired, one of the best flying 50mm EDF's I have ever built. I was using an Aura 5 Lite in auto launch mode and oddly had no directional control. Here are the remains after retrieving her from the tree. I am cutting number two as I type... stay tuned.

IMG_6792.jpg
 

speedy7385

Active member
Thanks Grifflyer for both great flying planes.
Grunjet lost radio signal and nose dived.
L-39 battery came loose in mid flight and crash landed on rooftop.
Will rebuild both.
Grifflyer, will you be able to send me the files for the 70mm EDF plan, would like to try that one out. Thanks!
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