PPRuNe Forums - The BIGGEST helico: the MI12!(rarely seen in flight)

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- - The BIGGEST helico: the MI12!(rarely seen in flight) (https://www.pprune.org/rotorheads/289897-biggest-helico-mi12-rarely-seen-flight.html)

It looks like the sort of thing Gerry Anderson would have dreamed up!

Brian;

The Mi-12 has a slightly Interleaving configuration, which can be seen on the plan view in page 82 of John Everett-Heath's book [above].

It looks like the higher thrust area of blades, which is near the tips, spend more time over the Mi-12 fuselage than over the fuselage of a tandem.

Just a guess.

Dave

http://nauka.relis.ru/25/9808/VINT-2.GIF

How little we know about Russian helicopters.

Earlier side-by-side helicopters;

In Russian; http://www.mai.ru/colleges/fac_1/kaf...es/prf_ipb.htm

Translated into English, hopefully; http://translate.google.com/translat...%3Den%26sa%3DN

Dave, the only real reason to do this now would be to get around the need to design a large rotor system. Even then MI-26 proves this is achievable. The biggest problem is the need for the MGB to handle a growth factor squared to the MUAW, while everything else is linear. This is due to the need to keep tip speeds below ~200 m/s, and handle same power so torque goes up.

Quote:

Originally Posted by Nick Lappos

It is a pickle that the tilt rotor folks solved using extremely stiff wings with composite materials. Most likely, these dynamic interactions created a real flight envelope problem that hampered the ability to put the aircraft into use. It is possible that modern computation could help the control system, and modern composite materials could help the stiffness.

Chinook LCT is an interesting example of the possibilities, although not used to overcome dynamic problems (from comments made here about Noth Sea ops maybe it should be). For something this big i imagine the rotor collective response time would be less than the stuctural period. The collective could trim to cancel out vertical accelerometer signals near hub, mixed in with pilot input. The whole thing starts to say FBW, which the MI-26 now is...

Mart,

Remember that the Side-by-Side Mi12 was intended to be a heavy lift transport craft, not a highly maneuverable attack helicopter.
______________________________________

In addition;

The world wants more fuel efficient vehicles.
Boeing is bringing out its 20% more efficient Dreamliner airplane.
Prouty says; "The overall airplane lift-to-drag ratio can be 10 to 30, depending on the configuration, whereas the maximum a helicopter can do is 4 to 6."
Prouty says, "... tail rotor absorbing 10 to 20 percent of the engine power".

One improvement is obvious;

http://www.unicopter.com/No_Tail_Rotor.gif

.... and there are many more to come from progressive manufacturers.

Dave

From your post, Dave, it seems we must get rid of rotorcrafts when we need an efficient aircraft!!! :mad: :ugh: :}