NOTAR

[horlick97]

Could I ask what's is the state of development of the NOTAR? I understand it was first instroduced by MD more than 10 years ago.

How does it compare with the conventional tail rotor helicopters in terms of the power taken away from lift by the internal fan to generate the compressed air in order to generate the Coanda effect?

In forward flight where counter torque is achieved by the vertical stabilizers, can the compressed air be directed totally rearwards to generate forward thrust? I note in the present MD models, this cannot be done.

Is this techology be scalable upward? Why so far there have not be larger helicopters designed with this technology? Is it due to limitations in the technology or patent protection?

Thanks in advance for any insights you may share.

[HeliHenri]

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Hello,

Some informations here : http://www.pprune.org/rotorheads/444591-why-hasnt-notar-taken-off-2.html

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[Vertical Freedom]

HuH is there really such a thing as a NOTAR :{

Mr Hiller had a similar concept loooong before Howie Hughes did :ooh:

The tail rotor/ anti torque device is hidden inside 520 boom doing the same jobie as the TR :8

Incoming :=

[RVDT]

Howie Hughes was long planted before the "NOTAR". :rolleyes:

[Ian Corrigible]

I understand it was first introduced by MD more than 10 years ago.
Reintroduced... :E

http://www.aviastar.org/foto/cierva_w9_2.jpg (http://www.aviastar.org/helicopters_eng/cierva_w9.php)

For its part MDHI still seems optimistic on the tech: there was a roadshow planned to "educate the masses" (http://www.aviationtoday.com/regions/usa/A-Modern-Love-Affair-Lynn-Tilton-and-U-S-Army-Aviation_75775.html) in 2012, while 2013 was apparently "the year of the NOTAR." (http://bit.ly/ZpYVFk)

I/C

[Vertical Freedom]

Hiller J-5 helicopter - development history, photos, technical data (http://www.aviastar.org/helicopters_eng/hiller_j-5.php)
Hiller J-10 The first NOTAR Helicopte built in America 1947. - YouTube

sorry to disappoint You guys but Guruji Hiller had the NOTAR in the bag long before Guru Hughes did :8
http://i1104.photobucket.com/albums/h338/rotors99/hiller_j-5.jpg

[helihub]

And the Cierva W9 (in Ian Corrigible's) pic first flew in 1945 before the Hiller - which did not take to the air until 1947...

[Vertical Freedom]

Hey Helihub

Yep Your right the W9 (notar) first flew in 1945 but the Hiller J5 flew in 46 just one year later :D Well that's what this site claims Hiller helicopters (http://www.aviastar.org/helicopters_eng/hiller.html)

Anways all this was before Hughie did his NOTAR :E

[horlick97]

I understand in NOTAR, it employs the principle of Coanda effect to generate the lateral force in the tail boom. So far in the MD models, the tail boom are all circular in its cross section.

My question is, why not make the tail boom a vertical wing, and employ the bernoulli principle to generate the lateral force from the downwash from the main rotor?

[Rotorbee]

I remember having seen this in a picture. Can't find it tough. It was a huge wing mounted vertically. About one meter high.
First: Boy that was ugly.
Second: I can only imagine that this thing would be hell to controll in an autorotation, since that wing would fly backwards with a lot of undesirable aerodynamic effects. The forces on that wing could be higher than what the pilot is capable of holding, because the center of lift would be way out of the normal range. Even if the pilot would be able to control zero lift, the "wing" would be dynamically instable and one would have to fight every single moment to keep the helicopter from spinning.
Third: In forward flight, there would be very little to no effect at all and therefore almost no yaw control, hence the ship would need another thing out there to keep it fly straight. How about a tiny tail rotor?
Forth: If one tried some fancy maneuvers like flying sideways a bit too fast, interesting things could happen.