The International Cessna^® 170 Association

Bruce, I got to fly one of PHI's 105s a few years ago... very rough (vibrations), going through translational lift just about shakes your fillings out. Great single engine characteristics and easy hover auto.
The Sikorski I flew was a fully articulated semi-rigid rotor system. I believe it could handle about -1 1/2 G. Much more negative than that and it would chop off the tail boom. I flew with one guy that just loved to do a semi-hammerhead/rotor-over... very uncomfortable in an old H-3. I didn't enjoy it very much.

I assumed that you might have BO 105 time since it is such a popular workhorse. I bet the BK 117 is very nice!
David

dacker wrote:The BO 105 is an amazing helicopter, old, but amazing. It has a rigid rotor system which allows it to make that sort of maneuver (As do most modern combat helicopters). For the uninitiated, many helicopters have teetering rotor systems that would snap off if subjected to negative G push overs like what was demonstrated. Not a pretty sight.
I bet Bruce has a little BO105 time!
David

The problem with the 2-bladed teetering rotor system (such as on the Robbie) is that when you do a negative push-over it unloads the rotor. The tail rotor then causes a right roll and if you try to correct the roll with left cyclic while the rotor is unloaded, the rotor head will bump the mast and cause mast/rotor separation - and as my heli instructor used to say: "You fall from the sky...."

regards

~Marc

Plummit wrote:
The problem with the 2-bladed teetering rotor system (such as on the Robbie) is that when you do a negative push-over it unloads the rotor. The tail rotor then causes a right roll and if you try to correct the roll with left cyclic while the rotor is unloaded, the rotor head will bump the mast and cause mast/rotor separation - and as my heli instructor used to say: "You fall from the sky...."

regards

~Marc

And yet one more reason not to get into a Helicopter.

Bill Hart wrote:
And yet one more reason not to get into a Helicopter.

Or a 170 if you intend to turn it upside down.

And the thread has come full circle.

N9149A wrote:

Bill Hart wrote:
And yet one more reason not to get into a Helicopter.

Or a 170 if you intend to turn it upside down.

And the thread has come full circle.

Maybe the FAA shoud do a SFAR on the 170!

regards

~Marc

And the thread has come full circle. Very Happy

I was always told that helicopters don't really fly, they just beat the air into submission

N2255D wrote:

And the thread has come full circle. Very Happy

I was always told that helicopters don't really fly, they just beat the air into submission

Naw. They make so much noise and vibration the earth rejects them. (Also one reason the earth rejects shakey Lycs so well.)

LOW FLIGHT

Oh! I have kinda slipped the surly bonds of earth
And danced the skies on laughter-silvered rotors;
Treeward I've climbed, and joined the tumbling mirth
Of sun-split branches- and done a hundred things
You have not dreamed of - hover turned and flew backward
Low in the sunlit raucus. Hov'ring there
I've chased the shouting wind along, and flung
My eager craft through footless halls of air.
Up (a little ways), the long delirous, burning blue,
I've topped the rotor-washed heights with easy grace
Where never lark, or even eagle dares fly (out of fear of being sucked into the rotors) -
And, while with external lifting mind I've hovered
The low uncontrolled sanctity of airspace'
Put my hand out and said "Thanks God!"

What Pilot Officer Gillespie Magee would have written had only he known the helicopter!

David