Whirly wrote:
I'll keep this brief as I don't really want to sabotage wibbly's thread. And I have far better things to do than argue with you anyway.
Somehow I doubt that; you're a woman, aren't you?
But nevermind that.
Dave Jackson is quite right. Quite right. But here's the deal: Let us all acknowlege that Dr. Igor ("that's EYE-gore") Bensen "invented" what we now call the gyrocopter. In fact, he even coined the term. Even the God-like Cmdr. Ken Wallis used a modified Bensen-type when he started tinkering with gyros (his had plainly tumbled) in 1957.
Ol' Dr. Bensen initially used a horrible little donk built by some American chainsaw company which the adverts said produced 70 horsepressure, a figure most of us think was a gross overstatement.
It was a toy - a sunny-day flivver, a poodle-jumper (German Shephards: out of the question!). It was never meant as a Serious Transportation Device. He knew it; we knew it...uhh, we were supposed to know it.
Well, leave it to the yanks. What is it they grunt all the time? MORE POWER! As light engine technology advanced, people began sticking more and more powerful (although in this case, "powerful" borders on hyperbole) motors in their gyros. The Rotax 447 must have seemed like a gift from heaven!
Along with more power came more speed, and so began the quest for a "...true, cross-country gyroplane!" as one manufacturer likes to (erroneously) claim.
Trouble was, the design was flawed. With a pusher prop and a high thrustline (necessary because of the bigger and bigger props), a dangerous condition could arise if the hapless pilot "unloaded" the rotor. Easy to do at the higher speeds or rates of climb that gyros were now attaining. With no drag now from the rotor and a thrust line well above the vertical centre of gravity...Wheeeee! Over we go, faster than it takes to say it.
The solution is to put the engine way down low in the frame. This results in gangly-looking ships (e.g. Dominator). Another solution is to put the dang donk out front like God and Juan de la Cierva intended it to be.
There are other problems with gyrocopter flight characteristics. Gust response can be confusing and dangerous. Structural rigidity comes into play too; some ships flex at the keel/mast attach point, which wreaks havoc with the control geometry. Dr. Bensen recognized this and added a cable between the rotor and the nose. But look at all the "modern" designs that eliminate it while trying to attack the problem from other angles. There's a lot to gyro design; it's not simply a matter of throwing a bunch of tubing together and going flying.
Maybe the real solution is to recognize that the "gyrocopter" is still just a calm, sunny-day, low-altitude toy...a toy that can kill you quick if you let it!