Military helicopter tail rotor solutions?

Question

Is anyone working on solving loss of tail rotor function from RPG's as seen in the movie "Black Hawk Down"? I've wondered this for many years, whether or not it's possible to design a system whereby tail rotor loss of function could be minimized by some kind of emergency jet propulsion in the tail section to produce the necessary thrust for safe control of the helicopter or by directing engine exhaust in a sidewards manner much like an engine reverse thruster to minimize or eliminate torque thrust. I'm also wondering why the military does not employ the NOTAR system in combat zone helicopters to mitigate being brought down by RPG's. Any helicopter engineers or pilots wish to comment?

I envision a jet propulsion system built into the tail and properly armored that is controlled by computer to alter it's amount of thrust as necessary depending on inputs from the pilot for course correction. Or a system of thrust vectoring of the primary engine exhaust. Such a system would provide emergency backup manuevering in the event of tail rotor loss or malfunction to provide ample time for evasion and descent in a controlled manner for both civilian and military helicopters. If Kelley Johnson and his engineers could build the SR-22 in an era of slide rules, we should be able to do this as well.

Answer 1

Hey Paul....I have seen a ducted exhaust version of the Sikorsky with twin counter-rotating wings...I'm pretty sure the twin engine ,twin lift ducted turbo exhaust will show up someday...but when is pretty hard to say. ...The advances come and go so quickly if you blink you might miss it...Anyway the no tail rotor system still lacks the capacity to work well at highest forward velocity and the military will always use the wait and see method when they are not sure...Perhaps any directional means will always be a problem for rotating wings...But I'm on your side here 100% when i say that if they had a backup that would get them 25 miles in an awkward descent that might be better than screwing into the desert...
Perhaps in the next few years the ducted fan/exhaust system will just pop up on an new version of the side by sides....good luck and keep asking those kind of questions its good to see them from time to time....From the E..

Answer 2

Although the "Black Hawk Down" incident was a highly publicized event, the fact is, tail rotor malfunction is not a common occurrence in helicopter crashes. In the case of Black Hawk Down, the helicopter was brought down by an unguided RPG. The fact that the tail rotor was hit was purely luck. Had the RPG hit anywhere else, the helicopter would have still crashed. There is no way to make every vehicle perfectly safe. Do helicopters crash from tail rotor malfunctions, absolutely. But the majority of those are from mechanical malfunctions. With a NOTAR system, the probability of similar mechanical malfunctions would be about the same as with a tail rotor. A failure in the NOTAR system would have the same result as a failure in the tail rotor. Therefore, there really is no benefit in spending billions of dollars to design a fleet of helicopters because of tail rotor failure. However, it does make sense to include NOTAR in future designs, but those will take decades to get implemented in the field.

Answer 3

Maybe avoiding generating the resulting torque in the first place by using contra-rotating blades?
Think, in theory at least, that they allow greater efficiency, and an increase in manoeuvrability, therefore allows greater performance, for the same engine/helicopter mass. Trouble is it more complex. Also helicopter is possibly just as vulnerable to a RPG, hitting the main rotors, as they are to one hitting the tail rotor.

Think NOTOR isn't as efficient as conventional tail rotor. Maybe there's also problems in reducing the infra-red signature of a helicopter equipped with such a system.

As a supplementary emergency measure NOTOR might be useful, but added in parallel it would add weight, and reduce the combat survivability of the helicopter.

Some kind of small "Rocket booster" might be feasible to produce an emergency counter to torque thrust, but don't think it's easy to make them "controllable" (the required torque thrust is likely to vary, making it difficult to predict how hard it should push) they add a potential explosion risk to the tail boom. Weight would also need to considered.

Answer 4

hmm u have a good point. does that new helicopter used by the marines have one? i think its called a CV-22.