Check Out Grifflyers L-39 Albatros! (Free Plans)

by FliteTest | December 7, 2018 | (8) Posted in Just Fun

This week on Friday’s Community Spotlight, we’re taking a look at a community member’s jet build. 

If you’re a fan of foam board jets, this awesome looking foam board L-39 Albatros might be the next build for you. Grifflyer has been responsible for a number of great foam board designs and has even been featured here on the Spotlight once before with his P-39. So what does this new foam RC jet have to offer? 


Free Plans: Download Here



Specs at a Glance

There are two versions of the L-39 that you can build. These are the EDF version and the Prop Version. 

EDF Version

Wingspan- 26in. 660mm.

Length- 27in. 685mm.

Wing area- 143 sq. in. 9.2 sq. dm.

Wing loading- 17.4 oz/sq. ft. 52g/sq. dm.

Dry weight- 12 oz. 340 grams

All up weight- 17oz. 482 grams

CoG- 2 in. from leading edge 51mm. from leading edge

Prop Version

Wingspan- 26in. 660mm.

Length- 27in. 685mm.

Wing area- 143 sq. in. 9.2 sq. dm.

Wing loading- 15.8 oz/sq. ft. 48 g/sq. dm.

Dry weight- 10.2 oz. 289 grams

All up weight- 15.7 oz. 445 grams

CoG- 1.5 in. from leading edge 38mm. from leading edge


Flight Video

I find, to get a true idea of how a plane will perform, it’s best to see a video. Thankfully, Grifflyer has provided us with one! Take a look.


Flying Characteristics

Here’s the designer, Grifflyer himself, to explain how the L-39 flies and what you can expect when you take up the controls for the first time. 


This thing looks fast - but how fast is it?

“Top speed is great when built as an EDF and slows down very well for landing, if built as a pusher prop jet the top end speed drops but your static thrust is much higher giving the plane a more "trainer" like feel.”


How would you describe the handling?

“When built as an EDF it tracks like an arrow and the controls are very smooth giving you the ability to fly like a pattern ship, but can become "snappy" and abrupt when you really start banging the sticks around. If you chose to build it with a pusher prop you'll find that it handles similar to a park flyer, but faster and less forgiving.”


How does it stall?

“If your plane stalls it will likely drop a wing but it is nowhere near entering a spin, all you have to do is level the wings and then power out. Due to the fact that a prop jet has more static thrust your recovery will eat up less altitude compared to the EDF setup.”


Can the L-39 do aerobatics?

“The aerobatic ability of this plane limited to the basics, Loops, Rolls, Inverted, Split S's etc.”


How do you launch the model?

“The method of launching the jet differs depending on how you choose to power it. If you built it with a ducted fan I suggest holding it right behind the trailing edge of the wing and tossing it from there. Let me rephrase that, don't give this a light gentle toss you need to get up to flying speed, because the ducted fan doesn't have enough static thrust to get it up to adequate airspeed before it hits the ground (ask me how I knowpastedGraphic.png) On the contrary never launch it like this if you built it with a prop setup as you run the risk of the prop striking your hand, what I do is hold it right in front of the intakes and give it a nice underhand toss and let the motor do the rest.”


What does it take to land the plane?

“Landing this model is quite simple all you need to do is bleed almost all your airspeed and get it close enough to good 'ol terra firma to put ground effect to work, then right before to hid land flare the plane and you'll "ride" a cushion of air to the ground.”


What would you say the skill level is?

“This depends on which variant you'll be building if you want to go prop powered then I'd suggest being able to fly all four channels very comfortably, if you want to build it as an EDF then you'll want to learn how to fly faster planes.”


Closing Thoughts on the L-39

If you’re looking for an all-around fun and great looking EDF or pusher jet for your fleet, Grifflyer’s L-39 is an awesome choice. Its size and flying characteristics allow you to fly it in a park or small field whilst the optional pusher prop configuration empowers even relatively new RC pilots to have a go. Great job Grifflyer!


If you want to read more about other community projects, visit the Flite Test Forum or check out these articles:

Community Messerschmitt BF 109!

Community Stuka Dive Bomber!

Community Mini Mirage Jet!


Article by James Whomsley

Editor of FliteTest.com

Contact: james@flitetest.com

YouTube Channel: www.youtube.com/projectairaviation 

COMMENTS

DeValk on December 7, 2018
What edf fan does it use ?
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grifflyer on December 7, 2018
I use a 50mm 11 blade 4500kv unit.
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Jackson T on December 7, 2018
I am so building that! What motor do you recommend? I've only got F pack motors.
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grifflyer on December 7, 2018
I used an F pack motor with a 20 amp esc and a 2200mah lipo battery. You might not be able to use a smaller battery unless you add nose weight.
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Jackson T on December 8, 2018
Hmm, the biggest I've got is a 800mah 3s!
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grifflyer on December 8, 2018
How many 800mah do you have?

If you have two you can hook them up in parallel and use less extra nose weight that way.
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Jackson T on December 10, 2018
I've got 2, do you think that will be enough?
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grifflyer on December 10, 2018
Yes I think that will work very well, you might need to add a little bit of nose weight to get it to balance properly.
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Fred2510 on December 8, 2018
Great that someone is contributing with Free pans.
Was a bit taken aback by the Weights tho... for 26" span flyers these are 16 oz !! models... That seems as Really heavy!
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grifflyer on December 9, 2018
I agree that 16 0z. does seem heavy when I first weighed it I was nervous if it would fly, but it flies very well and doesn't feel all that heavy.

I think the reason is that the wing loading on the l-39 is 17.4 oz./sq. ft. while something like the FT X-29 has a wing loading of 21.3 oz./sq ft. so it's actually not super heavy for its size.
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Grackle FPV on December 13, 2018
i really want to build this! but how do i get the plans to scale for my paper?
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grifflyer on December 14, 2018
All you have to do is open up the plans in adobe reader and select print. After the print window opens up there should be a section in the middle of the window labeled "Page Sizing & Handling" right below that there should be options to choose between "Size" "Poster" "Multiple" and "Booklet" You are going to want to select the "Poster" option. Next, ensure your tile scale is set to 100%, your overlap is set at 0.005 in. and that you have the "Tile only large pages" option selected. You can also select "Cut marks" which will make tiling the plans after they printed easier, but it will increase your page count from 8 to 12. Lastly, go down to the bottom of the print window and click print.

Good luck with the build.
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Grackle FPV on December 15, 2018
thanks so much! i look forward to building it

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mesadad on November 14, 2019
If i take this to a print shop, how big does the shops printer/plotter have to handle? How many sheets of foam does this take? Are you planning to turn this into a speed build kit with a build video? I know, lots of questions, hahah
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grifflyer on November 14, 2019
Hi Mesadad,
Each sheet of paper is 30x20 inches so you would want your plotter to be able to handle at least that much. If I remember correctly, this plane only requires two sheets of foam. If FT is willing I'd love for this to become an SBK. Good luck with your build!!

One other thing, if you're building this as an EDF I suggest you check out V2 of this design, it's basically the same plane and it flies the same, but it looks a whole lot better, easier to build, and looks a lot more like the real thing. https://forum.flitetest.com/index.php?threads/aero-l-39-albatros-v2-edf-jet.60299/
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mesadad on November 17, 2019
Thank you. I’m going to try and print it at a print shop today
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Check Out Grifflyers L-39 Albatros! (Free Plans)