The Aero L-39 Albatros is a Czechoslovakian high performance jet trainer developed in the 1960's. The L-39 has served with over 30 air forces around the world, and is the one of the most widely used trainers. Today the L-39 is used in the Reno air races jet class, flown by demonstration teams such as the Breitling Jet Team of France, and are privately owned by jet enthusiasts.
With this in mind I wanted to create a relatively easy to fly jet the was versatile and had a wide flight envelope. So after four months of work I give you the Grifflyer Aero L-39, a sport jet built out of two sheets of foam board that can be built as an electric ducted fan jet or as a pusher prop jet using standard components found in the Flite Test F pack.
Video:
Overview-
Speed-
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.
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.
Stalls-
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.
Aerobatics-
The aerobatic ability of this plane limited to the basics, Loops, Rolls, Inverted, Split S's etc.
Take offs-
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 know
) 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.
Landing-
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.
Skill level-
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.
Specs:
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
Plans:
Aero L-39 Albatros Plans
Instructions:
Aero L-39 Build Instructions
Gallery:
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