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A400M New Turboprop


Ryan130
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Bill

The aerial shot in the article made me look twice. I thought is was a \"Star Lizard\" for a second. Just needs the \"B\" model plug and it would pass for one.

I agree with ya, give it some time, it may be a good bird, then again it may not.

Herkeng

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Hi the reason the props rotate in opposite directions is quite simple; basically if all four props rotate the same way this makes the plane want to turn off in the opposite direction, a stability problem particularly if you have huge great engines like the A400M. Note that the only bigger turboprop engine ever is the Kuznetsov unit fitted to the Tu-95 Bear and some other less well known aircraft. These are fitted with a pair of contra-rotating props for the same reason. So Airbus opted for \"down between the engines\", with the inboard on each wing rotating clockwise and the outboard in the other direction. Someone was castigating the French for doing this under the assumption that there would have to be two types of engines, a clockwise and an counterclockwise variant, which would bring logistic and manufacturing problems. However the Frenchies (and Brits and Germans and Spanish and Italians in Airbus) thought of that, there is only one type of engine which rotates the prop in different directions depending on how it is geared.

Yrs GerryShaw

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It has been over 32 years since I was on 130\'s, but I think the T.O. 1-1 (C130)has a blurb that the vertical Stab is offset (L.E. to the right) a number of degrees to compensate for the torque pull. It\'s pretty \"hazy\", but it may be in the maintenance T.O.\'s. Can any one confirm this?

Glenn

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JoCrow wrote:

Vmca / P-factor - counter rotating props have a benefit.

C/R props enable the prop to rotate inboard on the downward side of the rotation. Props develop more lift while rotating down then when up.

This keeps the majority of the thrust working towards the inboard side of the aircraft and closer to the rudders.

At least this what all the books I have read on aerodynamics have stated.

The French appear to have found another reason to rotate the blades towards each other.

Testing and time will tell.

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When I went through Red Flag in \'83 were had a forum discussion on something. During the conversation we discussed the scenario of a flight of Hercs flying to Europe during a conflict in Europe, and the feasibility of protecting the formation. One suggestion was arming a few Hercs with missiles, Sidewinders, etc., and have them flying as part of the formation. The theory was that by them hiding with the formation that they could lock on and launch their missiles against any attacking aircraft. Guess it never caught on.

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