Comments on: Retreating blade stall

By: Michael

Michael — Mon, 10 Oct 2011 15:47:17 +0000

Nice Product, I Would Like to Have it,

Thanks For Information
See my Blade Helicopter MCX2 too

By: jjsiewertsen

jjsiewertsen — Mon, 22 Aug 2011 17:35:31 +0000

PS… servo-flap by KAMAN, vortex reducer by WESTLAND, mini tip jet engine by VORTECH, computer by YOU-NAME-IT
hollow mean-axle by me, (ray-input). Beam me up, Scotty!!!

By: jjsiewertsen

jjsiewertsen — Mon, 22 Aug 2011 14:28:59 +0000

To my knowledge the best solution to the problem of undesired stall is the use of an computer to control flaps to adjust the angle of attack and also the blade tip being equiped with boomerang-shaped vortex reducers, ciao, joja*

By: Jim Borger

Jim Borger — Wed, 17 Aug 2011 22:12:26 +0000

The only solution of going comparable airplane speeds in a helicopter is to slow the rotor. Check out Carter Copters. Their aircraft, a rotorcraft but not a helicopter, is currently flying as a gyrocopter but will later add wings and be a gyroplane capable of speeds up to 300 with a recip and 400 with a turbine with coast to coast non-stop range. One can only dream, for now.

By: Mike

Mike — Wed, 17 Aug 2011 01:06:11 +0000

Twin, counter rotating rotors, intermeshed or not, won’t eliminate retreating blade stall. You still have blades that are retreating….

In either case, the retreating blade still loses lift and flaps down increasing the angle of attack. Eventually the critical angle of attact will be exceeded and the blade will stall.

By: grumpy

grumpy — Sat, 13 Aug 2011 16:46:29 +0000

Intermeshing counter-rotating twin rotors, as in Anton Flettners’ wotld war II “Kolibri” helicopter, should aleviate the problem since the advancing blades are outboard of the fusalage. Comments?z2zf

By: Aero Guy

Aero Guy — Sat, 13 Aug 2011 14:05:35 +0000

The twin counter rotating blades would not solve the blade stall problem. If the blade stalls, you are less lift then you were before. If you were previously flying straight and level, and now you have less lift, you are either going to slow or drop altitude, or more likely both. You won’t start pitching up though, as the stalls pitching moment would be cancelled out by each other. Also – stalled blades produce much more drag requiring more power which may not be available.

The same design also does eliminate torque, but so does the tail rotor on a conventional helo, and for a given amount of power, the two provide approximately the same lift. If there was a huge benefit of using twin counter rotating rotors over tail rotor designs in terms of power required for a given weight, then the industry would have shifted that way quite a few years ago.

By: towser

towser — Sat, 13 Aug 2011 03:39:04 +0000

That’s why having twin counter rotating blades would do two things. Eliminate the blade stall problem, and the torque created by the single rotor. Is it the expense or the complicated engineering required that you don’t see it more often?

By: Tim

Tim — Fri, 12 Aug 2011 18:48:13 +0000

Mike….you’re a strange bird.

By: Mike Henry

Mike Henry — Fri, 12 Aug 2011 16:53:03 +0000

I once had a quarter horse named Blade whose stall became infested with ticks. I called Orkin to come treat the stall, which they did. After about a week I noticed there were still some ticks in Blade’s stall, so I called Orkin again and they came back out. When I drove by the barn, there they were, retreating blade’s stall.