Confusion

[RockyMountainPilot]

Right, so what your saying is that once I push past the opposing wings stop, the wing I'm pushing will continue to travel upward and eventually fold onto the other wing?!?!?! All I meant was that the travel of the wing eventually stops and then you are bending the wing.

 

You can't lift one of the wings when its detatched? Wheaties bud.

After a few long months I will be in Torrance...then I'll be as smart as you.

 

You might want to start calling them blades, not wings. You aren't bending the blade at all. There are three hinges on the mast head. One is the teetering hinge, and a coning hinge for each blade. After you attend the safety course, then you will realize what I am talking about. And when did I ever say the blade was not attached? When you lift if at the root, you are lifting it from one end and it is much more difficult than lifting it at the middle.

 

Also, I would drop the attitude if you expect to go anywhere in aviation. Pilot's with attitudes get people killed.

[coanda]

You might want to start calling them blades, not wings. You aren't bending the blade at all. There are three hinges on the mast head. One is the teetering hinge, and a coning hinge for each blade. After you attend the safety course, then you will realize what I am talking about. And when did I ever say the blade was not attached? When you lift if at the root, you are lifting it from one end and it is much more difficult than lifting it at the middle.

 

Also, I would drop the attitude if you expect to go anywhere in aviation. Pilot's with attitudes get people killed.

Ok relax..this is turning into a personal battle and I'm still on the recovery from Iraq/Afghanistan. Blade, wing, stick, board, who cares, you know what i was talking about. AFTER the the wing/blade/ thing that makes it fly is past its last hinge, if you had the power, you would start to bend the blade. All I was saying. We obviously were mixed up on the weight issue. Of course its difficult to push up at the root of the blade I thought you were reffering to its static weight or weight out of the box. That is all...I didn't have an attitude...I just thought you had one..all is even I suppose. Sorry.

[RockyMountainPilot]

Ok relax..this is turning into a personal battle and I'm still on the recovery from Iraq/Afghanistan. Blade, wing, stick, board, who cares, you know what i was talking about. AFTER the the wing/blade/ thing that makes it fly is past its last hinge, if you had the power, you would start to bend the blade. All I was saying. We obviously were mixed up on the weight issue. Of course its difficult to push up at the root of the blade I thought you were reffering to its static weight or weight out of the box. That is all...I didn't have an attitude...I just thought you had one..all is even I suppose. Sorry.

 

You can lift those blades to about 70 degrees up if I remember correctly before the blade hub hits the mast hub. There is no up limit stop. There is simply no need for one.

[mountainchopper]

You can lift those blades to about 70 degrees up if I remember correctly before the blade hub hits the mast hub. There is no up limit stop. There is simply no need for one.

 

 

fact of the matter is that the blades, when off the helicopter, don't weight sh*t. second if you are refering to a R44 then you are also displacing the hydro fluid so it isn't the blade that is resisting you it is the hydrolic cylinders. third if you didn't have an attitude in the first place you wouldn't wan t to be a pilot you'd be a hairstylist. attitude doesn't kill anyone, impacting the ground does, the two while seen together often don't necessarily go together.

 

p.s. i'm not trying to be antagonistic or a dick, but lets stop the bickering and talk about some autos

[RockyMountainPilot]

fact of the matter is that the blades, when off the helicopter, don't weight sh*t. second if you are refering to a R44 then you are also displacing the hydro fluid so it isn't the blade that is resisting you it is the hydrolic cylinders. third if you didn't have an attitude in the first place you wouldn't wan t to be a pilot you'd be a hairstylist. attitude doesn't kill anyone, impacting the ground does, the two while seen together often don't necessarily go together.

 

p.s. i'm not trying to be antagonistic or a dick, but lets stop the bickering and talk about some autos

 

When you teeter the blades, you do not move the hydraulic actuators one bit because the blades will feather. This is the whole idea behind teetering. When you cone the blades up, they do not change any pitch because the coning hinge is inline with the pitchlink.

 

And attitude kills a lot of people.

[mountainchopper]

When you teeter the blades, you do not move the hydraulic actuators one bit because the blades will feather. This is the whole idea behind teetering. When you cone the blades up, they do not change any pitch because the coning hinge is inline with the pitchlink.

 

interesting, logically what you say makes sense now that i think about it as far as the mechanical aspects of teetering. but the coning thing makes total sense, also doesn't a lot of the coning angle come form blade bend also? I am under the impression that the blades actually move very little while in flight but those little movements are enough to create rather large reactions as far as control results go. i will have to check this out at work tomorrow a little more closely when moving the blades during preflight.

 

back on subject: i.e. autos so i was thinking today how the different speeds of the relative wind affect the ammount of "thrust" and lift being created on various portions of the blade, now my question is: does the total lift vector on the driven portion of the blade fall behind the axis of rotation because the resultant relative wind is closer to horizontal due to a higher velocity, or does the tip voriticies causeing induced drag have more of an effect. hopefully this makes some shred of sense.

[Tenacious T]

And attitude kills a lot of people.

 

Not if you keep a level attitude

[RockyMountainPilot]

interesting, logically what you say makes sense now that i think about it as far as the mechanical aspects of teetering. but the coning thing makes total sense, also doesn't a lot of the coning angle come form blade bend also? I am under the impression that the blades actually move very little while in flight but those little movements are enough to create rather large reactions as far as control results go. i will have to check this out at work tomorrow a little more closely when moving the blades during preflight.

 

back on subject: i.e. autos so i was thinking today how the different speeds of the relative wind affect the ammount of "thrust" and lift being created on various portions of the blade, now my question is: does the total lift vector on the driven portion of the blade fall behind the axis of rotation because the resultant relative wind is closer to horizontal due to a higher velocity, or does the tip voriticies causeing induced drag have more of an effect. hopefully this makes some shred of sense.

 

The blades on the Robinsons don't bend like on other two bladed systems. That is the reason behind the coning hinge. It allows for a much lighter blade since it doesn't not have to absorb bending moments.

 

I am not following you with the auto questions at all. What do you mean "fall behind the axis of rotation"?

[Eric Hunt]

Mountain Chopper asked:

"does the total lift vector on the driven portion of the blade fall behind the axis of rotation because the resultant relative wind is closer to horizontal due to a higher velocity, or does the tip voriticies causeing induced drag have more of an effect."

 

First part - YES. Second part, sort of.

 

The total reaction (TR) appears at about 120 degrees tilted back from the relative airflow, but the angle varies with angle of attack and other factors.

 

At the hub, with lots of upflow and little rotational flow, the RAF is almost vertical, but the angle of attack is huge and the blade is stalled - drag in this region.

 

Moving out along the span, more rotational flow, same vertical upflow, but blade is almost unstalled. Still drag.

 

Bit further out, RAF is moving more towards the horizontal, blade is developing lift, total reaction is pointed forward, so it is helping pull the blade around.

 

Bit further out, blade is going great guns, TR still slightly forward, helping pull the blades. This region is providing your auto force to retain and increase RRPM.

Then the critical bit, with more rotational flow and same upflow, the RAF is at the position where the TR is now vertical - lots of lift, but no help for RRPM.

Any further out, and TR is trying to slow the blades.

 

At the tips, a bit of vortex generation also adds drag, but it's a fair bet that the TR pointing backwards is a bigger influence.

 

If you pull pitch, all the regions move further out along the blade - more stalled area inboard, a little less backwards TR outboard, but overall the drag overcomes the driving force and RRPM decreases.