Are there silent helicopters

We could see that it was infact a helicopter and I have heard stories of these type of copters. Does anyone know the purpose of these things? I have an idea what there for but I wanted to get some more information and input from others.

Silent helicopters have been around for a while now. Developed for military use. I will look to see if I can find some info to post on it for you.

Here is a program NASA was working on. Link: arc. I just posted on my sighting of one taking off from a Coast Guard base Apparently, these are usually black, silenced Blackhawks, that are involved with anti-drug operations Been around for a long time. Its purpose is simple to be not heard while in operation makes perfect sense to me. As someone who lives in the flight plan for Sikorsky Aircraft, there were some programs to quiet helecopter engine noise.

One project took a sensor and sampled the 'sounds' the gas turbines made. By inverting the sound wave you can cancel out alot of the sound emissions. Look at the Navy - they have alot of pratical applications with sound.

Subs have to be quiet How quiet are they? Originally posted by Eternal Does anyone know of anything about silent helicopters? The main engine has some kind of sound suppresion system similar to the ones used on the stealth airplanes.

In that book it says the system was first tested on a modified special operations MH-6, which in tests could hover in visual range without being heard. I have see two of these. Flying at mph and silent. I cant recall the VNE, but the really goes I think VNE is knots or so. If your not looking for a noise complant I'd suggest going for a fenstrom tail system..

The Exposed tail rotor system is the sourse of much of the noise of the helicopter I also give props to the with it's 5 bladed main rotor Like comparing a jetranger to a I've worked around all the ones your talking about.

But the N is a beast. Quite by helicopter standards. Theres a considerable difference in an older Raven and Astro, versus a newer Raven or Raven 2 also.

The exhaust was redesigned I think in 04 to deflect up rather than down, as well as redesigned blades, which makes an enormous difference in the noise level. I was amazed when I first hear the difference.

With my Raven II at AGL and some blade slap, I still have difficulty getting the attention of those indoors who are not expecting me. You can post now and register later. If you have an account, sign in now to post with your account.

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