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Old 28th Jun 2012, 19:09
  #216 (permalink)  
Lonewolf_50
 
Join Date: Aug 2009
Location: Texas
Age: 64
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FH, I don't think you understand what terms are being used here, nor their relationship. "Inane" would apply to a few of your comments in this discussion.

If you are in helo mode, the torque on your proprotor, be it on the right or the left, is an indication of the thrust you are producing in the vertical direction. A change in torque will be an indication of a change in thrust.

Let's talk about something you know well: a helicopter.

Case 1 is hover at Gross Weight X, with 70 % Torque required to hover.
Case 2 is hover at Gross Weight Y, with 77 % Torque required to hover.

Which hover requires more thrust? Thrust is a vector. Your torque is indicated in the cockpit, hence the thrust / torque in my discussion, since there isn't a THRUST gauge in the cockpit.

A pilot would know this, right?

For John: thanks for further enlightenment on Blackhawk stab failures, and others. A point that might be related to the V-22 mishaps may be germane: control authority. If that linkage broke, so much for flight control authority.

Aside: we were warned in the Seahawk about the limits in pitch authority with the stab at various angles of 'down." There was a placard in the cockpit, and as well as typical NATOPS test questions on airspeed limts for various stab down positions. Loss of control authority in the pitch channel can be fatal. (Related note: If you check the news from last year, the Navy lost a T-45 due to loss in pitch control authority, pilot bailed out. Appears to be a cause similar to the hardware issue found in the Bragg crash.)

We had cautions in the Huey NATOPS about tail rotor control authority limits (IIRC due to the chain / sprocket) such that on a hot day, at the bottom of an auto, IIRC the TH-1E, you could hit the stops and not have the control authority you had expected. Jack Carson and I discussed this a while back, I think he remembers it better than I.

Might the Osprey team want to look at control authority limits?
I am not sure.
It's not like the control linkage to an aileron or a tail rotor control linkage.

From the AF 447 threads, I have learned that control laws in some modern planes limit the control authority, or the "throw" you can achieve with a max deflection. There was a passenger liner near New York that lost its Vertical Stab due to what I think was exceeding design stength via over control, or excessive control authority.

FBW systems have plenty of limiting features.

IIRC, V-22 has an FBW, or FBW type system. Is there enough control authority for the operating environment?

That's a hard question. See the airliner above. If you increase control authority X amount, you may risk Y or Z damage or fatigue in a given control channel.

Interesting point to ponder.
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