Wednesday, October 14, 2009

Phoenix Flight Report

Josef Bostik and Jim Lee flew the big metal tube over to the Czech Republic to flight test the new Phoenix motorglider. We had visited the new factory in Usti nad Orlici earlier in the year to see the first prototype under construction, so we had already taken a close look at the construction of the aircraft. The prototype is mostly fiberglass construction for cost effectiveness. The production aircraft are carbon/aramid, with carbon being the predominant material, and aramid added to the cockpit area for crash protection. Here are Jim’s impressions:
Compared to the Lambada when viewed from the outside, four things are readily apparent. The fuselage is very streamlined, the canopy hinges at the front, the wings have a new shape, they are mounted low on the fuselage and there are full span flaperons. The low wing means that you step up onto the wing from the rear and then have an easy step down into the cockpit. The cockpit tapers back on the aft fuselage much further, so there isn’t the long skinny tailboom like on the Lambada. Also, the Phoenix uses two levers for the spoilers and flaps so that they can be used independently. The wing extensions are twice as long as the Lambada’s, hence the no wingtip span is around 36 feet.
Josef won the coin toss, and got to fly first. I got to take pictures as Josef and Martin taxied through the tall grass. This is one beautiful aircraft!

After they took off, and departed the area I looked at all of the unusual (to me) Czech and Russian built aircraft at the field. Amphibs, biplanes, gliders, motorgliders, towplanes and experimentals were all over the place. There were plenty of Sambas and Lambadas around too, including a tricycle Lambada. Every instrument panel on the field was rather spartan, without a single glass panel in any of them. (Am I a spoiled pilot or what?).
I headed for the end of the runway when I saw the Phoenix returning. There was a Lambda landing just ahead of the Phoenix, and I noticed a huge difference in wind noise between the two aircraft. The Phoenix has a light whistle to it much like a pure glider. It was a lot of fun watching the various angles of the Phoenix in the pattern, and I kept thinking, this is an awesome looking plane! After watching some boring landings it was my turn to hop in.
The first things you notice inside are the plush, black leather appointments, much like a luxury automobile. There are map pockets on the sides, and a large glove box on the panel. A stretched cockpit provides more leg and headroom than in the Lambada. For me, at six-one, it was nice to have a little more legroom. The center console which houses the flap, airbrake, and trim levers is very ergonomic, allowing easy access to these controls from both seats, and will allow an instructor to correct airbrake settings on final approach without excessive arm motions. These controls are far enough forward that the arm and elbow area is padded and comfortable. Just forward of the console on the floor is the tow release lever. The throttle, choke, and switches are positioned normally on the panel.
Starting the 100hp Rotax is straightforward. Throttle at idle, half choke if the engine is cold, no choke if the engine is warm. The Rotax cranks up immediately, as usual. With the forward hinged canopy, there are no worries about starting and taxiing with it open.
After securing the canopy, we advanced the throttle to full, and executed a no flap takeoff on the beautiful grass runway. We were off the ground in about 500 feet, even though the runway needed to be mowed, and climbed at 110kph, achieving 5m/s with two of us and half fuel. We climbed about 1000 meters, and then leveled off for cruise flight. 4700rpm resulted in a speed of 185kph. Slowing to 100kph, a few dutch rolls confirmed a roll authority slightly better than the aileron only Lambada. We shut down the engine and feathered the prop and using 0 degrees of flap we climbed at 2m/s. During the climb we intentionally slowed to the stall buffet (which is a little more pronounced than in the Lambada), and still had good aileron authority.
We headed for the next cloud about 4 miles away. Cruising at 95kph, the sink rate on the vario showed around 1m/s. When we hit the thermal, we again did not use the flaps initially, since I wanted to compare the flight characteristics with the Lambada. About the only change is the view out of the cockpit, with the low wing, and the out-of-sight cowling. Dropping the flaps 1 notch allowed us to slow the plane about 3-5kph with the same bank angle. The climb rate increased as is to be expected, and the roll authority remained good. There are two positive flap positions on the prototype, but this will be changed as explained later.
With the engine running again, we performed a full stall series with flaps up and down, and spoilers up and down, wings level and during turns, which all resulted in stable mushing stalls with no tendancies to spin, just like the Lambada.
Back into the pattern with a bunch of other aircraft, including a tow plane busy hauling gliders aloft, we entered downwind, and flew the approach without flaps. The spoilers rise higher out of the wing than the Lambada, and are more effective. Except for the different sight picture out of the cockpit, the landing went as expected. Full spoilers just before ground effect, and then just keep the plane flying until it touches down on three wheels. Full power, and we were off again in short order. The second landing was with full flaps (position 2 – about 20 degrees). The approach angle was a little steeper, but not much. But the flare angle of attack had a lower nose angle, meaning the mains touched first, then the tailwheel and I bounced it. Adding power, (I could almost hear Josef laughing), we went around for another go with flaps. Same result. OK, forget the flaps, in we came, and another nice 3 point landing. Conclusion; the Phoenix lands just like the Lambada without flaps, you could even call it autoland. Just pull back in the flare, and it lands three point. No special timing is required. But with flaps, the flare angle of attack is not a three point position, so it takes some special timing to pull it off. The second flap position isn’t really good for anything. A full spoiler approach with a slip is going to result in a higher sink rate than the flaps would produce. But one notch of flap is good for thermalling, and negative flap increases glide speed, so the final flap configuration will have this arrangement.
It was a warm day, and the canopy did not have opening side windows, so it got too hot in the cockpit. The vents will be reworked, and the canopy will have sliding windows as well, so that should help.
Much attention has been devoted to drag reduction. The cowling transitions into the canopy without an angle change. The lower bib cowling is also clean around the engine. The gear legs are flush with the bottom of the fuselage, and the legs themselves are cleaner, and stronger than the Lambada’s.
The wheelpants look extremely well designed, and since you don’t stand on the gear leg to get in, the pants should stay unblemished too. As mentioned, the aft cockpit area fairs back into the fuselage with a nice long recovery area, further reducing drag.

There were a lot of things to like about this new aircraft, and the only things we didn’t like (flap angle and air vents) will be changed for the production aircraft. The first production Phoenix is out of the molds, and when a composite junky like me sees all of that beautiful black carbon cloth everywhere, it makes my head swim (no it wasn’t the debrief Pilsners). The second production plane is being laminated in the molds, so epoxy is flying in the Phoenix shop.

The Lambada has always made a big impression among the crowds at airshows amidst the look-alike LSA’s (except for the Evektor SportStar, of course). But wait till the gang sees the new Phoenix; it is guaranteed to blow their minds! I know, it did that to me.