New Stuff from Martin Hollmann


Platinum Member
Nov 14, 2003
Seacoast New Hampshire, USA
Total Flight Time
Gyro - 2.5! FW, hundreds not thousands. Helo, 0 (some day!)
Guys, most of you probably know Martin Hollmann, one of the grand old men of gyro design. Martin was responsible for the first successful ultralight gyro, the Bumble Bee, and the first successful 2-seater gyro, the Sportster, but went on to work mostly in fixed-wing aircraft.

These days, Martin still promotes his Stallion kit, and does design and analysis work under contract. His son Eric has followed him as an aeronautical engineer. But both of them still have quite a taste for gyros.

Martin has new versions of his gyro book and software, and Eric has posted a paper on gyro stability that is of deepest interest to all of us. This is Martin's gyro page:

... and this is Eric's stability paper, which analyses gyro porpoising -- what we often dismiss as PIO. Two warnings: it is a VERY graphic intensive page, and you may not get through the math in one sitting, unless you are also an engineer. (I'm a safety and human factors guy -- compared to Eric and Martin, a mathematical lightweight. But I still benefited greatly from this).

(Eric put this up back in January, but the graphics weren't loading right, so I emailed Martin and waited for him to get it straightened out).

Much of the other gyro stuff on Martin's site is 2 years or more old (after all, his gyro designs date from the eighties) but that oscillation analysis is new and interesting.

Some people will not want to spend $220 for Martin's book and software. Uh-huh... I would hate to be tumbling out of the sky, out of ideas, airspeed, and rotor RPM (heck make that out of rotor blades) and suddenly think, "maybe I should have bought Martin's damn book!"