Takeoff Stability
Part 6
By Greg Gremminger
This may seem like a little thing, or an excuse for limited rotation angle on takeoff and landing. But, Some Magni “clones” have raised tails, presumably to be able to rotate to higher angles of attack on both takeoff and on landings. The intuitive and promoted advantage of being able to raise the nose further in a landing or takeoff stance is slower takeoffs and landings. But, some pilots have discovered that it takes proficient skills to apply this technique without getting into trouble. The ability to rotate too quickly to a high angle of attack can cause the gyro to jump out of ground effect losing airspeed and dropping back to the ground in a rough, nose high attitude. This has happened – with the associated roll‐over!
Magni gyros do not have raised tail booms, limiting the rotation angle on takeoff to an angle that prevents extreme jumps off the ground to get into this trouble.
Promoters of these high raised tail configurations also boast that they can land at slower airspeeds – higher disk angles of attack because they can touch down with a higher nose attitude. This is certainly true – can touch down at lower airspeeds and stop a bit shorter, maybe. But, that landing attitude also invites the ability for the rotor to strike the ground if the landing attitude is too severe. This has happened! Magni gyros do not encourage such tail low landings, but if you were to land on the tail wheel first, the tail forces the nose lower to avoid rotor strikes – maybe a bit rougher landing, but all the parts are still together!
Another reason that some gyro configurations have high tails is so that the horizontal stabilizer is in the propwash – to amplify the stability contribution of the horizontal stabilizer – when the prop is producing propwash. The propwash can have a nearly two to one effect on the power of the horizontal stabilizer. Actually, this is not necessary for Big Tails Way Back because they already have a strong leverage arm for dynamic damping effectiveness. With this horizontal stabilizer in the propwash arrangement, changes in power level can change the stability/handling characteristics of the whole machine between power on (best), and power off (not as much). Professional aircraft designers prefer that the control and handling properties, sensitivity to controls, does not change for any reason such as an abrupt power change. This is not such an issue for pilots experienced in this characteristic, but it can be an issue for more novice pilots expecting to penetrate wind gusts, for instance, with power off as well as they experienced with power on.
Magni may have the most extensive experience of gyroplane developers in these subtle variations and configuration issues. Over the years they have actually progressed through 24 (latest is the M24) configurations (many of these being non‐production prototype configurations to test various concepts). The production flock of Magni gyros today take advantage of these years of prototype and testing experience and Magni Gyro has only released configurations to the public upon extensive evolution to those production configurations. Discouragingly, some designers have simply taken an intuitive concept, applied it to an obvious beneficial configuration (Magni “clones”), and released production models without such extensive evolution and iteration with prototype models. In my opinion, this diligence to evolution and testing is the major “Magni Difference”.
