MBB Bo-209 Monsun: Few and Far Between
Text and Photos by Budd Davisson, Air Progress, Dec, 1990

Curious about those long wings and their adverse yaw, I put my feet flat on the floor and racked the stick from one side to the other. I had expected a reasonable amount of adverse yaw but got practically none, proving the machine could probably be flown with the feet removed from the control equation — a nasty way to go flying but indicative the airplane is well-designed.

Most of the ten Monsuns imported had a 150 fixed pitch and fixed nose gear. It's unknown how many are still registered.

While we were poking around in the airplane's envelope we were flying through one of the most picturesque skyscapes of big and little puffies which combined with the absolute unlimited visibility of the airplane, to give us one of the more beautiful days for flying that I've seen in the last few years. Every little nuance the air had to offer was fed through the controls to my right hand. I was impressed by the airplane's control feel, not only the response, but the relative balance between the three axis. Obviously the folks at Messerschmitt-Boelkow-Blohm had done their homework.

Pulling the, power back, I had expected the airplane to deaccelerate a little faster than it did but no big deal since dropping the nose gear out at 110 knots acted as a very effective speed brake. I held the nose several degrees above the horizon as I edged the stick back, patiently waiting for the airplane to stall. When it did stall, the edge of the stall was a little sharpish which, had I known the airfoil was a 64 series Laminar, would have surprised me. The airplane tried to roll right fairly briskly, so I tried an accelerated stall to the right from about 45 degrees and the airplane once again tried to tuck to the right. I did the same accelerated stall in a left turn and the airplane again (surprise!) wanted to tuck to the right. I think what we have here is a minor rigging problem.

Just for the hell of it, I flew the airplane down to the edge of the stall then increased the power and dropped the nose just enough to bring it a couple of knots out of the stall but leave it in hard buffet. I began making gentle turns left and right and then started making hard turns left and right — soon realizing if the wing was sitting on the right side of the lift curve it was perfectly willing to do anything asked. I spent more than the average amount of time slugging around at much less than 60 knots in bank angles as high as 45 degrees with absolutely no trouble. It was really impressive to see how positive and coordinated both the rudder and elevator were in this exercise since a lot of airplanes wouldn't have been anywhere near as kind as the 209.

It didn't take long before I began inventing reasons to keep the airplane in the air to fly a little bit longer. One of these reasons was to do a series of stability tests — the primary one being to pull the nose 15 knots off trim speed and let go. After four of five cycles, the Monsun had fairly well damped out, but wasstill searching up and down in a very long period phugoid that would eat up about 300 feet in both directions and showed no indications of damping out past that.

We were up high and close to the airport, so I glanced over at the airspeed noticing the red line was up in the 180 knot range with the yellow arc extending up to around 140 knots. With those kinds of numbers available, I just brought the power back, stuck the nose down and watched the vertical speed indicator wrap around to about 2500 feet a minute down — putting us back at pattern altitude in a fraction of the time it would have taken us in some sort of high-wing spam can. Those who haven't flown air-planes with aerobatic capabilities and, therefore, high red lines can't appreciate how nice it is to be able to simply poke the nose down and let the speed run up without worrying about overstressing the airplane in turbulence or overrunning the red line. This ability to maintain altitude until close to your destination is really handy and also enables you to stay up in the smooth air longer.

It took a little work to get the airplane down to 110 knots so we could throw the nosewheel out (which, from that point on, acted as a great drag brake). Flying downwind at about 90 knots. I chopped the power opposite the runway. bringing the speed down to the 75 knots indicated that Art recommended. I toggled the flaps about half way out, stopping them on the high side of the 15-degree extension mark on the indicator between the seats. I was reasonably certain those long wings would let the airplane glide like a Schwietzer sailplane, so I moved base leg out a little bit to give some room. Turning final, I ran the rest of the flaps out down to 35 degrees and found I had underestimated the effects of those big boards. The flaps not only added a lot of drag. but brought the airplane out of the air like an anchor.

Throughout the entire flight, I had been mindful of the elevator trim which is a wheel between the seats that was much more powerful than most aircraft. However, even in approach mode I found it no problem to just tweak the wheel a little one way or the other. During the entire flight, it's doubtful the trimwheel moved more than 30-45 degrees full travel because it is so powerful.

Walking around the airplane on the ground. I had noticed the spring loaded tailskid on the fuselage and Art had mentioned it's quite common for pilots to drag the tail on landing so, as we approached the numbers and flared, I was careful to notice where the nose was so I wouldn't overrotate once the mains touched. The airplane sat in ground effect and gave plenty of time to maintain an attitude as I held it off until the mains forcefully squeaked on and the nose stayed in the air. Lowering the nose for a go-around, Art said "watch this" and reached over and shoved in the throttle. As he did, we levitated off the ground in level attitude because the flaps were fully extended. The airplane didn't seem to care and just kept on trucking. We had only about 50 feet of altitude when Art reached over and toggled the flaps all the way up with a single motion, rather than milking them in slow-ly. The airplane was accelerating so fast that as the flaps came in, the Monsun gained the necessary speed. Even though I was flying the airplane, it did nothing to let me know they had been retracted. That's impressive. Subsequent landings confirmed what I had seen on the first landing — the Monsun's an absolute pussycat to land and capable of tremendous precision.

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