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Free-fall Autorotate?

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phr8dawg

Well-known member
Joined
Jan 15, 2006
Posts
181
So James Bombed and Jinx push the Hughes 500 Notar out of the Antonov and start it in freefall. It was more fun than the roach race in my room. So...

Without hydraulic boost, will a chopper autorotate?

Could you start one in freefall given the airloads?

Where can I get lessons?
 
So James Bombed and Jinx push the Hughes 500 Notar out of the Antonov and start it in freefall. It was more fun than the roach race in my room. So...

Without hydraulic boost, will a chopper autorotate?

Could you start one in freefall given the airloads?

Where can I get lessons?
Yes and Yes.
I don't know about the NOTAR, but the earlier McD versions (OH-6, H500, MD-500D/MD) had no hydraulics anyway. As long as you are flat pitch during startup, I don't see a problem other than trying to keep it from tumbling like a rock.

I went to my friendly Army recruiter to get my lessons.
 
I appreciate the legit answers. What would keep a notar machine in a straight line while autorotating? You'd think it would rotate opposite the main rotor having no counteracting tail rotor.

Aw,its just a movie. Anybody know where I can get a Star Wars speeder bike?
 
I appreciate the legit answers. What would keep a notar machine in a straight line while autorotating? You'd think it would rotate opposite the main rotor having no counteracting tail rotor.

Aw,its just a movie. Anybody know where I can get a Star Wars speeder bike?

Same reason an autogyro doesn't rotate opposite the blade direction; there's no power being applied to the blades.
 
Yup, until you pull pitch to arrest your descent you don't need to use the anti-torque pedals.
 
Yup, until you pull pitch to arrest your descent you don't need to use the anti-torque pedals.

Well, the TR drive shaft is still turning because it's connected to the transmission, right? Isn't the NOTAR the same except, intsead of a really long drive shaft and TR, it has a shorter shaft that drives a fan? The fan still turns so there is still thrust being generated, right?

Just some thoughts since I have never seen a real, live NOTAR before.

Just wondering, did the helicopter slide out nose or tail first? I still think with the high CG it would try to flip on its back. If it went out nose first it might porpoise nose up/down, but the nose would still be pointed downward. But what about the blades at that second that they hit the slipstream?

Sounds like a task for the Myth Busters!
 
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I believe thrust is being generated, but not sideways. If you look at the tail boom of a NOTAR helicopter, you will notice the end of the boom rotates to vector the thrust. So if thrust is not needed, it goes to a neutral, no-thrust position. (At least I think that's how that works, as I have no experience w/a NOTAR either.) Any one else have anything to add?
 
Well, the TR drive shaft is still turning because it's connected to the transmission, right? Isn't the NOTAR the same except, intsead of a really long drive shaft and TR, it has a shorter shaft that drives a fan? The fan still turns so there is still thrust being generated, right?
Not quite. There is neither a fan nor a rotor in the tail. Anti-torque is handled through a slit along the tail boom creating a low pressure area on one side (the Coandă effect).
 
Aside from the fact you would disintegrate into a massive mess of metal and plastic when falling vertically with no Nr... no, it would not work.

Please refer to most helicopter manuals that state the importance of maintaining rotor speed. Good movie... totally fake helo ending.
 

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