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Old 05-17-2007 | 11:04 PM
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erbroens
 
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From: Curitiba, Parana, BRAZIL
Default RE: L-39 test flight

Well, again we checked everything and after fueling the plane , cycling the landing gear and taking a deep breath I flipped the switch , starting the led sequence and advanced the throttle .. as usual the P-120 started to life, then we closed the turbine hatch and canopy and taxied to the heading... the ground handling of the plane was good even in the strong wind.

Having a trailing edge nose gear I expected a good takeoff run, even in a crosswind.. The plane performed as expected, and it went straight as a arrow... however it showed a slight tendency to "dive" the nose as the speed was increasing on ground.. I started to compensate with "up" elevator and it rotated after 100 meters of run.. the rotation was not super smooth but it was not bad... then I needed to add 2 clicks of elevator and aleiron and the plane was flying well.

The plane was very good, it flies pretty much like the Savex L-39 but with a huge advantage on the visibility due to its size.. it also is very stable and the CG seems right at the factory setting... however I didn´t followed the instructions and didn´t dialed the 30% expo recommended in the elevator. I used 15% and the plane was slightly pitch sensitive around neutral.. however the plane was flying good enough to handle it to my friend to enjoy it a little while. After 1 or 2 minutes (about 4 from takeoff) I got the radio back to prepare to land the beast..already a bit nervous about the crosswind.

After bleeding some speed with the turbine running at about 40% trottle I flipped the gear switch and then the flaps.. almost no pitch trim happened and then advanced the stick to 50% to make a inspection pass.. and then things started to worry me. Just one wheel lowered !! then I cicled the gear again and It didn´t move anymore.. I has only one main gear wheel stuck down, without able to do a belly landing on the grass... After discussing the situation with the owner, (LOL) we decided not to land it on the grass, instead on the strip. Then I proceeded as it was a normal landing, trying to touch down it as smooth as I could avoiding wing damage. The procedure was as usual, a rectangular approach at about 40% of power reducing the throttle as needed to keep a nice descent rate without fiddling too much with the elevator.. then when the plane was about 30 meters before the runway heading the throttle was chopped down and flared it as well as I could.

The plane responded very well in this conditions. It didn´t dropped a wing or wobbled. It was very firm and it landed on it´s single wheel without bouncing. It runned a little on it and then the wing and nose started to drop, making a sickening noise on the strip of fiberglass
being sanded... the single wheel brake was also not working and the plane used about 100m of the strip when it stopped in the lawn.

However the noise, the damage was minimal, and the culprit was a defective air valve at the wing root. The air pressure went to zero when it failed and thus made impossible lower the gear..

this is a pic taken right after the landing .. the wing tip tank has a big hole and there is a small scratch.. seems that in this circunstances we decided the right thing to do..



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