h a l f b a k e r yQuis custodiet the custard?
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Problem statement:
google for "helicopter crash tail rotor" and you will know.
Solution:
Add a jet just behind the cockpit as a substitute for the tail rotor. When the tail rotor fails, the tail jet should fires automatically. If it does not, the pilot must be able to fire it up manually too.
This
jet , due to fuel capacity limitations may burn for around 5 to 10 minutes only - just enough to take precautionary measures, finding a safe landing spot and landing.(This is not based on any data, this is my really wild guess. can anybody give me a more accurate estimate/solution?).
No Tail Rotor
http://www.mdhelico...TAR/About_Notar.htm
[AbsintheWithoutLeave, Oct 29 2005]
Werewolf helicopter gunship
http://www.centenni...y/Soviet/HE19G7.htm
Used counter-rotating rotor design. [Adze, Nov 03 2005]
[link]
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Auto-rotation is how they bring down a helicopter when the tail rotor fails. If the main rotor fails your screwed anyway. |
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Some helicopetes use engine exhaust to serve the function of a tail rotor. |
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The Hughes (or McDonnell-Douglas) NOTAR are tail-rotorless craft that use vectored exhaust for anti-torque. |
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Auto-rotation produces no torque so, during auto-rotation as long as some forward motion is maintained, no anti-torque is needed to maintain flight during an emergency descent. You do lose yaw control at the flare, though, so an idea for emergency secondary yaw control isn't such a bad idea. Having a large amount of lateral thrust so close to the center of rotation, "just behind the cockpit" isn't a great idea unless the whole tail boom is gone, too. |
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Jet: long-lasting, slow to run up, expensive, complex, heavy. |
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Rocket: short-burning, quick igniting, cheap, simple, light. |
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Otherwise, not such a bad idea. |
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Rockets aren't throttleable or really very controllable. |
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Liquid fuel rockets are ok, but then they are more complex and heavier than solid fuel. |
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With jet I did not mean the exact Jet engine. All I meant was some thing which will give a pressurised flow of steam/burning fuel ... beer? ;-) |
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Also, the thing can be right behind the Cockpit compared to the rotor. |
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Though there are rear - rotorless helicopters, what can we do about the thousands of helicopters that are already existing? |
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Simply fitting them with a jet/rocket will be a nice idea. |
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I just got another idea.. How about blowing off the main blades and deploying parachutes? |
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I do believe that there are helicopters that use exploding bolts to blow off the rotors. |
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I do not see a need for this idea. Because you can land a helicoptor that has lost its tail rotor, because of auto rotation. |
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If gas turbine fails and you lose power, your screwed anyway. |
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How long does it take for a jet engine to fire up? Isnt it a relatively slow process? Can it fire up in time to counteract the loss of the rear rotor? |
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It need not be exactly a jet.. as I said above, it could be anything that can let a controlled steam/pressurized gas that can couteract the force. |
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Apparently a small glowworm colony should fulfil these needs... |
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or, two main rotors rotating in opposite
directions. |
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I would think that in the event of a rotor failure, it would also destroy the systems that support the backup jet as well. |
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I would think that in the event of a rotor failure, it would also destroy the systems that support the backup jet as well. |
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...Thinking it twice doesn't help. |
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So my rotor is failing, looks like I might be in some trouble, no place to land in sight! |
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I should plaster myself against the ground even faster in a dramatic blaze of glory! |
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You haven't noted which way the jet faces; I'll assume it's not downward pointing as that would take a pretty strong powerplant. |
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If you have it replacing the tail-rotor's function then you will be imparting quite a sideways motion to your whirlybird if it's close to the main rotor's axis. |
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But If you have it rear-facing, you can now *fly* as an autogyro and have more control over where you're going to land in autorotation. |
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//If you have it replacing the tail-rotor then you will be imparting a sideways motion to your whirlybird// |
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...How would that be different to the original tail rotor? |
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//Also, the thing can be right behind the Cockpit compared to the rotor// - No it can't. It's a leverage thing. Maximum thrust/torque ratio will come from having it out on the end of the tail boom. |
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[custard] anno edited for clarity. |
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